First Diagnostic Test for Long Covid, Detecting Spike Protein in Blood, to Launch in September. Or is it ‘Long Vaccine’?

Authors{ WILL JONES 3 SEPTEMBER 2022 

The first diagnostic designed to identify patients with Long Covid has received CE-IVD marking in Europe, meaning it is ready for its formal launch in countries accepting the designation this month. It works by looking for “patterns of inflammatory marker expression” in the blood, and in particular for the Covid spike protein persisting in white blood cells. Business Wire has the story.

The simple blood test can help to objectively diagnose patients suffering from Post-Acute Sequelae of COVID-19 (PASC), commonly known as Long Covid. Developed by IncellDx, the test will be available to prescribers and patients in September through one of the world’s largest providers of diagnostic services.

A CE Mark indicates that the incellKINE Long Covid In Vitro Diagnostic fulfills the requirements of relevant European product directives and meets all the requirements of the relevant recognised European harmonised performance and safety standards…

The CE marking is supported by data from a validation study conducted by one of the world’s largest providers of diagnostic services, showing the test provides greater than 90% accuracy across Covid strains. The test was developed based on clinical studies published in the peer reviewed journal Frontiers in Immunology, which showed that IncellDx researchers generated credible, objective disease scores for Long Covid using machine learning and artificial intelligence to measure and analyse sets of inflammatory markers called cytokines and chemokines. The studies also demonstrated that patients with previous COVID-19 infection and lingering symptoms were found to have a distinct immunologic profile characterised by patterns of inflammatory marker expression. In a subsequent publication, IncellDx found SARS CoV-2 S1 spike protein in monocytic reservoirs of Long Covid patients up to 15 months after acute infection. These papers can be found here and here.

Patterson added, “Long Covid presents a significant diagnostic and treatment challenge for patients. Many of the symptoms that are associated with long Covid, including fatigue, brain fog, shortness of breath, insomnia, and a wide range of cardiovascular issues, can easily be mistaken for other conditions like post-Lyme, ME-CFS, Fibromyalgia, or even the common cold. Having an effective – and importantly an objective – tool to diagnose the condition is absolutely essential. An objective test that can detect immune signatures specific to Long Covid is vital for effective diagnosis and to enable patients to seek effective treatment.”

Patients who have or think they may have Long Covid can learn more and register for a test here.

One question is how it will distinguish Long Covid from ‘Long Vaccine’. The same research team behind this test also investigated whether vaccination produced a similar syndrome characterised by lingering spike protein, immune inflammation and the typical symptoms. They found it did: spike protein persistence from vaccination appeared, they said, to be a “major contributor” of symptoms similar to Long Covid post-vaccination. Further, given that the spike protein “alone delivered by vaccination can cause similar pathologic features”, they concluded it may be a “major contributor” of Long Covid symptoms post-infection as well. In other words, Long Covid after infection may be being caused or prolonged by spike protein from the vaccine rather than the infection. It’s not clear if the new diagnostic test will distinguish between these causes (or if that’s possible).

A Key to Long Covid Is Virus Lingering in the Body, Scientists Say

Virus remaining in some people’s bodies for a long time may be causing longer-term complications, recent research suggests

Authors:  Sumathi Reddy Sept. 8, 2022 The Wall Street Journal

The virus that causes Covid-19 can remain in some people’s bodies for a long time.  A growing number of scientists think that lingering virus is a root cause of long Covid.

New research has found the spike protein of the SARS-CoV-2 virus in the blood of long Covid patients up to a year after infection but not in people who have fully recovered from Covid. Virus has also been found in tissues including the brain, lungs, and lining of the gut, according to scientists and studies 

The findings suggest that leftover reservoirs of virus could be provoking the immune system in some people, causing complications such as blood clots and inflammation, which may fuel certain long Covid symptoms, scientists say. 

A group of scientists and doctors are joining forces to focus research on viral persistence and aim to raise $100 million to further the search for treatments. Called the Long Covid Research Initiative, the group is run by the PolyBio Research Foundation, a Mercer Island, Wash., based nonprofit focused on complex chronic inflammatory diseases. 

“We really want to understand what’s at the root of [long Covid] and we want to focus on that,” says Amy Proal, a microbiologist at PolyBio and the initiative’s chief scientific officer. Dr. Proal has devoted her career to researching chronic infections after developing myalgic encephalomyelitis/chronic fatigue syndrome, an illness that shares similar symptoms with long Covid, in her 20s.  She has mostly recovered now but has symptoms she manages.

Three long Covid patients, frustrated at the lack of answers and treatments, have helped connect researchers. 

“Long Covid is this really incredible emergency,” says Henry Scott-Green, one of the patients, a 28-year-old in London who says brain fog, extreme fatigue and other debilitating long Covid symptoms prevented him from resuming full-time work as a product manager, though he plans to return soon. “We’re really trying to run really efficiently and cut out as many layers of bureaucracy as possible.”

So far, the group says it has received a pledge of $15 million from Balvi, an investment and direct giving fund established by Vitalik Buterin, the co-creator of the cryptocurrency platform Ethereum. een says debilitating long Covid symptoms have prevented him from resuming full-time work.

Among the strongest evidence of viral persistence in long Covid patients is a new study by Harvard researchers published Friday in the journal of Clinical Infectious Diseases. Researchers detected the spike protein of the SARS-CoV-2 virus in a large majority of 37 long Covid patients in the study and found it in none of 26 patients in a control group.

Patients’ blood was analyzed up to a year after initial infection, says David R. Walt, a professor of pathology at Brigham and Women’s Hospital in Boston and Harvard Medical School and lead researcher of the study. Dr. Walt isn’t currently involved with the long Covid initiative. 

A year after infection, some patients had levels of viral spike protein that were as high as they did earlier in their illness, Dr. Walt says. Such levels long after initial infection suggest that a reservoir of active virus is continuing to produce the spike protein because the spike protein typically doesn’t have a long lifetimehe adds.

Dr. Walt plans to test antivirals such as Paxlovid or remdesivir to see if the drugs help clear the virus and eliminate spike protein from the blood.  He says it’s possible that for some people, the normal course of medication isn’t enough to clear the virus. Such cases may require “a much longer exposure to these antivirals to fully clear,” says Dr. Walt.

One of the research group’s goals is to find a way for people to identify whether they continue to have the virus in their bodies. There is no easy way to determine this now. 

Long Covid patients experience such a wide range of long-term symptoms that scientists think there is likely more than one cause, however. Some cases may be fueled by organ damage, for instance. 

Yet consensus is growing around the idea that lingering virus plays a significant role in long Covid. Preliminary research from immunologist Akiko Iwasaki’s laboratory at Yale University documented T or B cell activity in long Covid patients’ blood, suggesting that patients’ immune systems are continuing to react to virus in their bodies. Dr. Iwasaki is a member of the new initiative. 

In a 58-person study published in the Annals of Neurology in March, University of California, San Francisco researchers also found SARS-CoV-2 proteins circulating in particles in long Covid patients’ blood, especially in those with symptoms such as fatigue and trouble concentrating.

Now, the group is completing a study using imaging techniques and tissue biopsies to detect persistent virus or reactivation of other viruses in tissue. It also is looking at T-cell immune responses in tissues and whether they correlate with symptoms. 

Some people may harbor the virus and don’t have long-term symptoms, says Timothy Henrich, an associate professor of medicine at UCSF involved with the study and a member of the long Covid initiative. For others, lingering virus may produce problems.

“I think there’s a real amount of mounting evidence that really suggests that there is persistent virus in some people,” says Dr. Henrich.

Vascular and organ damage induced by mRNA vaccines: irrefutable proof of causality

Authors: Michael Palmer, MD and Sucharit Bhakdi, MD August 19, 2022 Popular Science

This article summarizes evidence from experimental studies and from autopsies of patients deceased after vaccination. The collective findings demonstrate that

  1. mRNA vaccines don’t stay at the injection site by instead travel throughout the body and accumulate in various organs,
  2. mRNA-based COVID vaccines induce long-lasting expression of the SARS-CoV-2 spike protein in many organs,
  3. vaccine-induced expression of the spike protein induces autoimmune-like inflammation,
  4. vaccine-induced inflammation can cause grave organ damage, especially in vessels, sometimes with deadly outcome.

We note that the damage mechanism is which emerges from the autopsy studies is not limited to COVID-19 vaccines only but is completely general—it must be expected to occur similarly with mRNA vaccines against any and all infectious pathogens. This technology has failed and must be abandoned.

While clinical case reports (e.g. [1,2]) and statistical analyses of accumulated adverse event reports (e.g. [3,4]) provide valuable evidence of damage induced by mRNA-based COVID-19 vaccines, it is important to establish a causal relationship in individual cases. Pathology remains the gold standard for proof of disease causation. This short paper will discuss some key findings on autopsy materials from patients who died within days to several months after vaccination. For context, some experimental studies are briefly discussed as well.

1. Most of the evidence presented here is from the work of pathologist Prof. Arne Burkhardt, MD

  • Dr. Burkhardt was approached by the families of patients deceased after “vaccination”
  • Autopsy materials were examined by standard histopathology and immunohistochemistry
  • Based on the findings, most deaths were attributed to “vaccination” with a high to very high degree of likelihood

Prof. Burkhardt is a very experienced pathologist from Reutlingen, Germany. With the help of his colleague Prof. Walter Lang, he has studied numerous cases of death which occurred within days to several months after vaccination. In each of these cases, the cause of death had been certified as “natural” or “unknown.” Burkhardt became involved only because the bereaved families doubted these verdicts and sought a second opinion. It is remarkable, therefore, that Burkhardt found not just a few but the majority of these deaths to be due to vaccination.

While all four major manufacturers of gene-based vaccines were represented in the sample of patients studied by Burkhardt and Lang, most patients had received an mRNA vaccine from either Pfizer or Moderna. Some of the deceased patients had received both mRNA- and viral vector-based vaccines on separate occasions.

2. Pfizer’s own animal experiments show that the vaccine quickly distributes throughout the body

In order to cause potentially lethal damage, the mRNA vaccines must first distribute from the injection site to other organs. That such distribution occurs is apparent from animal experiments reported by Pfizer to Japanese authorities with its application for vaccine approval in that country [5]. Rats were injected intramuscularly with a radioactively labelled model mRNA vaccine, and the movement of the radiolabel first into the bloodstream and subsequently into various organs was followed for up to 48 hours.

The first thing to note is that the labelled vaccine shows up in the blood plasma after a very short time—within only a quarter of an hour. The plasma level peaks two hours after the injection. As it drops off, the model vaccine accumulates in several other organs. The fastest and highest rise is observed in the liver and the spleen. Very high uptake is also observed with the ovaries and the adrenal glands. Other organs (including the testes) take up significantly lower levels of the model vaccine. We note, however, that at least the blood vessels will be exposed and affected in every organ and in every tissue.

The rapid and widespread distribution of the model vaccine implies that we must expect expression of the spike protein throughout the body. For a more in-depth discussion of this biodistribution study, see Palmer2021b.

3. Expression of viral proteins can be detected with immunohistochemistry

While the distribution of the model vaccine leads us to expect widespread expression of the spike protein, we are here after solid proof. Such proof can be obtained using immunohistochemistry, which method is illustrated in this slide for the vaccine-encoded spike protein.

If a vaccine particle—composed of the spike-encoding mRNA, coated with lipids—enters a body cell, this will cause the spike protein to be synthesized within the cell and then taken to the cell surface. There, it can be recognized by a spike-specific antibody. After washing the tissue specimen to remove unbound antibody molecules, the bound ones can be detected with a secondary antibody that is coupled with some enzyme, often horseradish peroxidase. After another washing step, the specimen is incubated with a water-soluble precursor dye that is converted by the enzyme to an insoluble brown pigment. Each enzyme molecule can rapidly convert a large number of dye molecules, which greatly amplifies the signal.

At the top right of the image, you can see two cells which were exposed to the Pfizer vaccine and then subjected to the protocol outlined above. The intense brown stain indicates that the cells were indeed producing the spike protein.

In short, wherever the brown pigment is deposited, the original antigen—in this example, the spike protein—must have been present. Immunohistochemistry is widely used not only in clinical pathology but also in research; it could readily have been used to detect widespread expression of spike protein in animal trials during preclinical development. However, it appears that the FDA and other regulators never received or demanded such experimental data [6].

4. Expression of spike protein in shoulder muscle after vaccine injection

This slide (by Dr. Burkhardt) shows deltoid muscle fibres in cross section. Several (but not all) of the fibres show strong brown pigmentation, again indicating spike protein expression.

While the expression of spike protein near the injection site is of course expected and highly suggestive, we would like to make certain that such expression is indeed caused by the vaccine and not by a concomitant infection with the SARS-CoV-2 virus. This is particularly important with respect to other tissues and organs which are located far away from the injection site.

5. Coronavirus particles contain two prominent proteins: spike (S) and nucleocapsid (N)

To distinguish between infection and injection, we can again use immunohistochemistry, but this time apply it to another SARS-CoV-2 protein—namely, the nucleocapsid, which is found inside the virus particle, where it enwraps and protects the RNA genome. The rationale of this experiment is simple: cells infected with the virus will express all viral proteins, including the spike and the nucleocapsid. In contrast, the mRNA-based COVID vaccines (as well as the adenovirus vector-based ones produced by AstraZeneca and Janssen) will induce expression only of spike.

6. Infected persons express the nucleocapsid protein (and also the spike protein)

This slide simply illustrates that the method works: lung tissue or cells from a nasal swab of a person infected with SARS-CoV-2 stain positive for nucleocapsid expression, whereas cultured cells exposed to the vaccine do not (but they stain strongly positive for the spike protein; see inset at the top right of Slide 3).

7. Injected persons express only the spike protein, which implicates the vaccine

Here, we see immunohistochemistry applied to heart muscle tissue from an injected person. Staining for the presence of spike protein causes strong brown pigment deposition. In contrast, only very weak, non-specific staining is observed with the antibody that recognizes the nucleocapsid protein. The absence of nucleocapsid indicates that the expression of the spike protein must be attributed ot the vaccine rather than an infection with SARS-CoV-2.

We will see shortly that the strong expression of spike protein in heart muscle after vaccination correlates with significant inflammation and tissue destruction.

8. Expression of spike protein within the walls of small blood vessels

We see spike protein expression in arterioles (small arteries; left) as well as in venules (small veins) and capillaries (right). Expression is most prominent in the innermost cell layer, the endothelium. This makes the endothelial cells “sitting ducks” for an attack by the immune system.

9. Endothelial stripping and destruction of a small blood vessel after vaccination

We now turn to the evidence of immune attack on the endothelial cells which produce the spike protein. On the left, a normal venule, delimited by an intact endothelium and containing some red blood cells and few white blood cells (stained blue) inside.

The image on at the centre shows a venule that is being attacked and destroyed by the immune system. The outline is already dissolving, and the spindle-shaped (and swollen) endothelial cells have peeled off from the vessel wall. Furthermore, we see lymphocytes—the small cells with dark, round nuclei and with very little cytoplasm around them; a single lymphocyte (at much higher magnification) is shown on the right.

Lymphocytes are the backbone of the specific immune system—whenever antigens are recognized and antibodies are produced, this is done by lymphocytes. Also among the lymphocytes we find cytotoxic T cells and natural killer cells, which serve to kill virus-infected cells—or ones that look to them as if infected, because they have been forced to produce a viral protein by a so-called vaccine.

A crucial function of the endothelium is to prevent blood clotting. Thus, if the endothelium is damaged, as it is in this picture, and the tissues beyond it make contact with the blood, this will automatically set off blood clotting.

10. A crack in the wall of the aorta, lined by clusters of lymphocytes, leading to aortic rupture

On the left, a section through the wall of an aorta. This picture is taken at an even lower magnification than the one before; the lymphocytes now appear as just a cloud of tiny blue specks. To the left of this blue cloud, we see a vertical crack running through the tissue. Such a crack is also visible macroscopically in the excised specimen of an aorta shown on the right.

The aorta is the largest blood vessel of the body. It receives the highly pressurized blood ejected by the left ventricle of the heart, and it is thus exposed to intense mechanical stress. If the wall of the aorta is weakened by inflammation, as it is here, then it may crack and rupture. Aortic rupture is normally quite rare, but Prof. Burkhardt found multiple cases in his limited number of autopsies. Some of the affected aortas were also shown to have expressed the spike protein.

11. Healthy heart muscle tissue, and lymphocytic myocarditis

In Slide 7, we saw that heart muscle cells strongly expressed the spike protein after vaccine injection. Here, we see the consequences. The picture on the shows a sample of healthy heart muscle tissue, with regularly oriented and aligned heart muscle fibres. On the right, we see a heart muscle sample from one of the autopsies. The muscle fibres are disjointed and disintegrating, and they are surrounded by invading lymphocytes. Burkhardt found myocarditis in multiple of his deceased patients.

12. Lymphocytic infiltration and proliferative inflammation in lung tissue

On the left, we see healthy lung tissue, with air-filled spaces (the alveoli), delimited by delicate alveolar septa with embedded, blood-filled capillaries. We also see some larger blood vessels.

On the right hand side, we see lung tissue overrun by lymphocytes. The air-filled spaces have largely disappeared and been filled with scar (connective) tissue. This vaccine-injected patient would obviously have had very great trouble breathing.

Lymphocytic infiltration, inflammation and destruction were also observed in many other organs, including the brain, the liver, the spleen, and multiple glands. However, instead of illustrating them all, we will conclude the pathological evidence with another immunohistochemistry result, which strikingly shows the long duration of spike protein expression.

13. Vaccine-induced expression of spike protein in a bronchial biopsy nine months after vaccination

The slide shows a sample of bronchial mucous membrane, from a patient who is alive but has suffered respiratory symptoms ever since being vaccinated. We see several cells in the uppermost cell layer that strongly express spike protein—and this even nine months after his most recent vaccine injection! While this is indeed the most extreme case of long-lasting expression, there is evidence both from Burkhardt’s autopsies and from published studies on blood samples [7] or lymph node biopsies [8] to indicate that expression does last several months.

14. The Pfizer vaccine mRNA gets copied (“reverse-transcribed”) into DNA and inserted into the cellular genome

The official mRNA vaccine narrative maintains that the modified mRNA contained in the vaccine will not be replicated in vivo; expression of the spike protein should therefore cease once the injected RNA molecules have been degraded.

The limited experimental studies available [9,10] suggest that the injected modified mRNA should be degraded within days to a few weeks of the injection. This is obviously difficult to square with the observed long-lasting expression; in some form or other, the genetic information appears to be perpetuated in vivo.

A recent experimental study from Sweden [11] has shown that human-derived cells can copy the Pfizer mRNA vaccine into DNA and then insert it into their own chromosomal DNA. The image shows the key evidence from this study. The cells were exposed to the vaccine for the lengths of time indicated. Cellular DNA was then isolated, and inserted DNA copies of the vaccine mRNA detected by PCR amplification of a fragment 444 base pairs (bp) in length.

All samples labelled with “BNT” had been treated with the vaccine, and they all show a PCR product of the expected length, as is evident from comparison to a DNA fragment length standard (“L”). Samples labelled with “Ctrl n” were controls: Ctrl 1– 4 contained DNA from cells not incubated with vaccine, Ctrl 5 contained RNA (not DNA) from vaccine-treated cells; Ctrl 6 contained the same but was additionally treated with RNAse, which step was also performed in the purification of DNA samples. As expected, none of the control samples contain the PCR product.

Considering Aldén’s observation of DNA insertion in every single experimental sample, it seems highly likely that this will also occur in vivo. Beyond providing a plausible mechanism for perpetuating the expression of spike protein, DNA insertion also poses risks of genetic damage, leading to cancers and leukemias.

15. Summary

The evidence presented here clearly demonstrates a chain of causation from vaccine injection to

  • rapid distribution of the vaccine through the bloodstream,
  • widespread spike protein expression, prominently in blood vessels, and
  • autoimmune-like inflammation and organ damage.

Vaccine-induced vascular damage will promote blood clotting, and clotting-related diseases such as heart attack, stroke, lung embolism are very common in the adverse events databases [4,12].

In addition to autoimmune-like inflammation, other disease mechanisms, including prion-mediated CNS degeneration [13], aberrant vascular protein deposition (amyloidosis) [14,15], and lipid nanoparticle toxicity [16], are plausible but require further study and corroboration. Overall, these vaccines can no longer be considered experimental—the “experiment” has resulted in the disaster that many medical doctors and scientists predicted from the outset [17]. The vaccination must be stopped, and all approvals and authorizations of their use must be revoked.

References

  1. Bozkurt, B. et al. (2021) Myocarditis With COVID-19 mRNA Vaccines. Circulation 144:471-484
  2. Ehrlich, P. et al. (2021) Biopsy-proven lymphocytic myocarditis following first mRNA COVID-19 vaccination in a 40-year-old male: case report. Clinical research in cardiology official journal of the German Cardiac Society 110:1855-1859
  3. Rose, J. and McCullough, P.A. (2021) A Report on Myocarditis Adverse Events in the U.S. Vaccine Adverse Events Reporting System (VAERS) in Association with COVID-19 Injectable Biological Products. Current problems in cardiology p. 101011
  4. Shilhavy, B. (2022) 43,898 Dead, 4,190,493 Injured Following COVID Vaccines in European Database of Adverse Reactions.
  5. Anonymous, (2020) SARS-CoV-2 mRNA Vaccine (BNT162, PF-07302048) 2.6.4 Summary statement of the pharmacokinetic study [English translation].
  6. Latyopva, A. (2022) Did Pfizer Perform Adequate Safety Testing for its Covid-19 mRNA Vaccine in Preclinical Studies? Evidence of Scientific and Regulatory Fraud.
  7. Bansal, S. et al. (2021) Cutting Edge: Circulating Exosomes with COVID Spike Protein Are Induced by BNT162b2 (Pfizer-BioNTech) Vaccination prior to Development of Antibodies: A Novel Mechanism for Immune Activation by mRNA Vaccines. J. Immunol. 207:2405-2410
  8. Röltgen, K. et al. (2022) Immune imprinting, breadth of variant recognition and germinal center response in human SARS-CoV-2 infection and vaccination. Cell (preprint)
  9. Andries, O. et al. (2015) N1-methylpseudouridine-incorporated mRNA outperforms pseudouridine-incorporated mRNA by providing enhanced protein expression and reduced immunogenicity in mammalian cell lines and mice. J. Control. Release 217:337-344
  10. Pardi, N. et al. (2018) Nucleoside-modified mRNA vaccines induce potent T follicular helper and germinal center B cell responses. J. Exp. Med. 215:1571-1588
  11. Aldén, M. et al. (2022) Intracellular Reverse Transcription of Pfizer BioNTech COVID-19 mRNA Vaccine BNT162b2 In Vitro in Human Liver Cell Line. Curr. Issues Mol. Biol. 44:1115-1126
  12. Anonymous, (2021) OpenVAERS.
  13. Perez, J.C. et al. (2022) Towards the emergence of a new form of the neurodegenerative Creutzfeldt-Jakob disease: Twenty six cases of CJD declared a few days after a COVID-19 “vaccine” Jab. ResearchGate (preprint)
  14. Charnley, M. et al. (2022) Neurotoxic amyloidogenic peptides in the proteome of SARS-COV2: potential implications for neurological symptoms in COVID-19. Nat. Commun. 13:3387
  15. Nyström, S. and Hammarström, P. (2022) Amyloidogenesis of SARS-CoV-2 Spike Protein. J. Am. Chem. Soc. 144:8945-8950
  16. Palmer, M. and Bhakdi, S. (2021) The Pfizer mRNA vaccine: Pharmacokinetics and Toxicity.
  17. Bhakdi, S. et al. (2021) Urgent Open Letter from Doctors and Scientists to the European Medicines Agency regarding COVID-19 Vaccine Safety Concerns.

CDC Quietly Removes Statement that Says “mRNA and the Spike Protein Do Not Last Long in the Body” from Their Website

Authors: Jim Hoft Published August 14, 2022 

The US Center for Disease Control and Prevention (CDC) has taken down from its website the statement that states “mRNA and the spike protein do not last long in the body.”

On July 15, the CDC quietly modified its website, removing the section that suggested mRNA and spike protein do not last in human bodies.

Under this topic, it stated that “our cells break down mRNA from these vaccines and get rid of it within a few days after vaccination.”

“Scientists estimate that the spike protein, like other proteins our bodies create, may stay in the body up to a few weeks,” it continued.

The CDC’s decision to remove this information about mRNA and spike proteins from the public is still an open question.

Below is the updated information on the CDC website:

Source: CDC

Research conducted by a third party and linked to the CDC at the bottom of this page reveals the following:

How long mRNA lasts in the body

The Pfizer and Moderna vaccines work by introducing mRNA (messenger RNA) into your muscle cells. The cells make copies of the spike protein and the mRNA is quickly degraded (within a few days). The cell breaks the mRNA up into small harmless pieces. mRNA is very fragile; that’s one reason why mRNA vaccines must be so carefully preserved at very low temperatures.

How long spike proteins last in the body

The Infectious Disease Society of America (IDSA) estimates that the spike proteins that were generated by COVID-19 vaccines last up to a few weeks, like other proteins made by the body. The immune system quickly identifies, attacks and destroys the spike proteins because it recognizes them as not part of you. This “learning the enemy” process is how the immune system figures out how to defeat the real coronavirus. It remembers what it saw and when you are exposed to coronavirus in the future it can rapidly mount an effective immune response.

When you click on the link, a popup notification will appear that says, “CDC cannot attest to the accuracy of a non-federal website.”

“However, a peer-reviewed study by researchers at Stanford University finds that the spike protein created by the COVID vaccines remains in the body much longer than believed and at levels higher than those of severely ill COVID-19 patients,” Clark County Today reported.

“Dr. Robert Malone, the key developer of the mRNA technology in the Pfizer-BioNTech and Moderna vaccines, said the findings were “buried” in the study, which was published by the journal Cell. He described the results as a potential “health public policy nightmare” in an analysis on his Substack page,” the outlet added.

It should be clear by now that Americans were lied to about the vaccine and its effectiveness.

A study published in the New England Journal of Medicine and conducted in Israel found that the immunity against the delta variant of SARS-CoV-2 waned in all age groups a few months after receipt of the second dose of vaccine, as reported by The Gateway Pundit.

“These findings indicate that immunity against the delta variant of SARS-CoV-2 waned in all age groups a few months after receipt of the second dose of vaccine,” the study concluded.

And according to a study published by CDC in February this year, the Covid booster mRNA vaccine effectiveness wanes after 4 months during the omicron period.

“During the Omicron-predominant period, VE against COVID-19–associated ED/UC visits and hospitalizations was 87% and 91%, respectively, during the 2 months after a third dose and decreased to 66% and 78% by the fourth month after a third dose. Protection against hospitalizations exceeded that against ED/UC visits.” the CDC said.

The Centers for Disease Control and Prevention also quietly released new guidelines on the COVID vaccination last week, as reported by TGP.

In a news briefing on Thursday, Greta Massetti, chief of the CDC’s Field Epidemiology and Prevention Branch, said, “The current conditions of this pandemic are extremely different from those of the prior two years.”

Adverse effects of COVID-19 vaccines and measures to prevent them

Authors: Kenji Yamamoto Virol J. 2022; 19: 100. Published online 2022 Jun 5. doi: 10.1186/s12985-022-01831-0 PMCID: PMC9167431PMID: 35659687

Abstract

Recently, The Lancet published a study on the effectiveness of COVID-19 vaccines and the waning of immunity with time. The study showed that immune function among vaccinated individuals 8 months after the administration of two doses of COVID-19 vaccine was lower than that among the unvaccinated individuals. According to European Medicines Agency recommendations, frequent COVID-19 booster shots could adversely affect the immune response and may not be feasible. The decrease in immunity can be caused by several factors such as N1-methylpseudouridine, the spike protein, lipid nanoparticles, antibody-dependent enhancement, and the original antigenic stimulus. These clinical alterations may explain the association reported between COVID-19 vaccination and shingles. As a safety measure, further booster vaccinations should be discontinued. In addition, the date of vaccination should be recorded in the medical record of patients. Several practical measures to prevent a decrease in immunity have been reported. These include limiting the use of non-steroidal anti-inflammatory drugs, including acetaminophen to maintain deep body temperature, appropriate use of antibiotics, smoking cessation, stress control, and limiting the use of lipid emulsions, including propofol, which may cause perioperative immunosuppression. In conclusion, COVID-19 vaccination is a major risk factor for infections in critically ill patients.

COVID Vaccines Increase Adverse Events and Weaken The Immune System

The coronavirus disease (COVID-19) pandemic has led to the widespread use of genetic vaccines, including mRNA and viral vector vaccines. In addition, booster vaccines have been used, but their effectiveness against the highly mutated spike protein of Omicron strains is limited. Recently, The Lancet published a study on the effectiveness of COVID-19 vaccines and the waning of immunity with time [1]. The study showed that immune function among vaccinated individuals 8 months after the administration of two doses of COVID-19 vaccine was lower than that among unvaccinated individuals. These findings were more pronounced in older adults and individuals with pre-existing conditions. According to the European Medicines Agency’s recommendations, frequent COVID-19 booster shots could adversely affect the immune response and may not be feasible [2]. Several countries, including Israel, Chile, and Sweden, are offering the fourth dose to only older adults and other groups rather than to all individuals [3].

The decrease in immunity is caused by several factors. First, N1-methylpseudouridine is used as a substitute for uracil in the genetic code. The modified protein may induce the activation of regulatory T cells, resulting in decreased cellular immunity [4]. Thereby, the spike proteins do not immediately decay following the administration of mRNA vaccines. The spike proteins present on exosomes circulate throughout the body for more than 4 months [5]. In addition, in vivo studies have shown that lipid nanoparticles (LNPs) accumulate in the liver, spleen, adrenal glands, and ovaries [6], and that LNP-encapsulated mRNA is highly inflammatory [7]. Newly generated antibodies of the spike protein damage the cells and tissues that are primed to produce spike proteins [8], and vascular endothelial cells are damaged by spike proteins in the bloodstream [9]; this may damage the immune system organs such as the adrenal gland. Additionally, antibody-dependent enhancement may occur, wherein infection-enhancing antibodies attenuate the effect of neutralizing antibodies in preventing infection [10]. The original antigenic sin [11], that is, the residual immune memory of the Wuhan-type vaccine may prevent the vaccine from being sufficiently effective against variant strains. These mechanisms may also be involved in the exacerbation of COVID-19.

Some studies suggest a link between COVID-19 vaccines and reactivation of the virus that causes shingles [1213]. This condition is sometimes referred to as vaccine-acquired immunodeficiency syndrome [14]. Since December 2021, besides COVID-19, Department of Cardiovascular Surgery, Okamura Memorial Hospital, Shizuoka, Japan (hereinafter referred to as “the institute”) has encountered cases of infections that are difficult to control. For example, there were several cases of suspected infections due to inflammation after open-heart surgery, which could not be controlled even after several weeks of use of multiple antibiotics. The patients showed signs of being immunocompromised, and there were a few deaths. The risk of infection may increase. Various medical algorithms for evaluating postoperative prognosis may have to be revised in the future. The media have so far concealed the adverse events of vaccine administration, such as vaccine-induced immune thrombotic thrombocytopenia (VITT), owing to biased propaganda. The institute encounters many cases in which this cause is recognized. These situations have occurred in waves; however, they are yet to be resolved despite the measures implemented to routinely screen patients admitted for surgery for heparin-induced thrombocytopenia (HIT) antibodies. Four HIT antibody-positive cases have been confirmed at the institute since the start of vaccination; this frequency of HIT antibody-positive cases has rarely been observed before. Fatal cases due to VITT following the administration of COVID-19 vaccines have also been reported [15].

As a safety measure, further booster vaccinations should be discontinued. In addition, the date of vaccination and the time since the last vaccination should be recorded in the medical record of patients. Owing to the lack of awareness of this disease group among physicians and general public in Japan, a history of COVID-19 vaccination is often not documented, as it is in the case of influenza vaccination. The time elapsed since the last COVID-19 vaccination may need to be considered when invasive procedures are required. Several practical measures that can be implemented to prevent a decrease in immunity have been reported [16]. These include limiting the use of non-steroidal anti-inflammatory drugs, including acetaminophen, to maintain deep body temperature, appropriate use of antibiotics, smoking cessation, stress control, and limiting the use of lipid emulsions, including propofol, which may cause perioperative immunosuppression [17].

To date, when comparing the advantages and disadvantages of mRNA vaccines, vaccination has been commonly recommended. As the COVID-19 pandemic becomes better controlled, vaccine sequelae are likely to become more apparent. It has been hypothesized that there will be an increase in cardiovascular diseases, especially acute coronary syndromes, caused by the spike proteins in genetic vaccines [1819]. Besides the risk of infections owing to lowered immune functions, there is a possible risk of unknown organ damage caused by the vaccine that has remained hidden without apparent clinical presentations, mainly in the circulatory system. Therefore, careful risk assessments prior to surgery and invasive medical procedures are essential. Randomized controlled trials are further needed to confirm these clinical observations.

In conclusion, COVID-19 vaccination is a major risk factor for infections in critically ill patients.

References

1. Nordström P, Ballin M, Nordström A. Risk of infection, hospitalisation, and death up to 9 months after a second dose of COVID-19 vaccine: a retrospective, total population cohort study in Sweden. Lancet. 2022;399:814–823. doi: 10.1016/S0140-6736(22)00089-7. [PMC free article] [PubMed] [CrossRef] [Google Scholar]

2. European Centre for Disease Prevention and Control. Interim public health considerations for the provision of additional COVID-19 vaccine doses. https://www.ecdc.europa.eu/en/publications-data/covid-19-public-health-considerations-additional-vaccine-doses. Accessed 4 May 2022.

3. Mallapaty S. Fourth dose of COVID vaccine offers only slight boost against Omicron infection. Nature. 2022 doi: 10.1038/D41586-022-00486-9. [CrossRef] [Google Scholar]

4. Krienke C, Kolb L, Diken E, Streuber M, Kirchhoff S, Bukur T, et al. A noninflammatory mRNA vaccine for treatment of experimental autoimmune encephalomyelitis. Science. 2021;371:145–153. doi: 10.1126/science.aay3638. [PubMed] [CrossRef] [Google Scholar]

5. Bansal S, Perincheri S, Fleming T, Poulson C, Tiffany B, Bremner RM, et al. Cutting edge: circulating exosomes with COVID spike protein are induced by BNT162b2 (Pfizer–BioNTech) vaccination prior to development of antibodies: a novel mechanism for immune activation by mRNA vaccines. J Immunol. 2021;207:2405–2410. doi: 10.4049/jimmunol.2100637. [PubMed] [CrossRef] [Google Scholar]

6. BNT162b2 Module 2.4. Nonclinical Overview. FDA-CBER-2021-4379-0000681 JW-v-HHS-prod-3-02418.pdf (judicialwatch.org) Access 6 May 2022.

7. Ndeupen S, Qin Z, Jacobsen S, Bouteau A, Estanbouli H, Igyártó BZ. The mRNA-LNP platform’s lipid nanoparticle component used in preclinical vaccine studies is highly inflammatory. Science. 2021;24:103479. doi: 10.1016/j.isci.2021.103479. [PMC free article] [PubMed] [CrossRef] [Google Scholar]

8. Yamamoto K. Risk of heparinoid use in cosmetics and moisturizers in individuals vaccinated against severe acute respiratory syndrome coronavirus. Thromb J. 2021 doi: 10.1186/s12959-021-00320-8. [PMC free article] [PubMed] [CrossRef] [Google Scholar]

9. Lei Y, Zhang J, Schiavon CR, He M, Chen L, Shen H, et al. SARS-CoV-2 spike protein impairs endothelial function via downregulation of ACE 2. Circ Res. 2021;128:1323–1326. doi: 10.1161/CIRCRESAHA.121.318902. [PMC free article] [PubMed] [CrossRef] [Google Scholar]

10. Liu Y, Soh WT, Kishikawa JI, Hirose M, Nakayama EE, Li S, et al. An infectivity-enhancing site on the SARS-CoV-2 spike protein targeted by antibodies. Cell. 2021;184:3452–66.e18. doi: 10.1016/j.cell.2021.05.032. [PMC free article] [PubMed] [CrossRef] [Google Scholar]

11. Cho A, Muecksch F, Schaefer-Babajew D, Wang Z, Finkin S, Gaebler C, et al. Anti-SARS-CoV-2 receptor-binding domain antibody evolution after mRNA vaccination. Nature. 2021;600:517–522. doi: 10.1038/s41586-021-04060-7. [PMC free article] [PubMed] [CrossRef] [Google Scholar]

12. Desai HD, Sharma K, Shah A, Patoliya J, Patil A, Hooshanginezhad Z, et al. Can SARS-CoV-2 vaccine increase the risk of reactivation of Varicella zoster. Systematic review. J Cosmet Dermatol. 2021;20:3350–3361. doi: 10.1111/jocd.14521. [PMC free article] [PubMed] [CrossRef] [Google Scholar]

13. Barda N, Dagan N, Ben-Shlomo Y, Kepten E, Waxman J, Ohana R, et al. Safety of the BNT162b2 mRNA Covid-19 v in a nationwide setting. N Engl J Med. 2021;385:1078–1090. doi: 10.1056/NEJMOA2110475/SUPPL_FILE/NEJMOA2110475_DISCLOSURES.PDF. [PMC free article] [PubMed] [CrossRef] [Google Scholar]

14. Seneff S, Nigh G, Kyriakopoulos AM, McCullough PA. Innate immune suppression by SARS-CoV-2 mRNA vaccinations: the role of G-quadruplexes, exosomes, and MicroRNAs. Food Chem Toxicol. 2022;164:113008. doi: 10.1016/J.FCT.2022.113008. [PMC free article] [PubMed] [CrossRef] [Google Scholar]

15. Lee EJ, Cines DB, Gernsheimer T, Kessler C, Michel M, Tarantino MD, et al. Thrombocytopenia following Pfizer and Moderna SARS-CoV-2 vaccination. Am J Hematol. 2021;96:534–537. doi: 10.1002/AJH.26132. [PMC free article] [PubMed] [CrossRef] [Google Scholar]

16. Yamamoto K. Five important preventive measures against the exacerbation of coronavirus disease. Anaesthesiol Intensive Ther. 2021;53:358–359. doi: 10.5114/ait.2021.108581. [PubMed] [CrossRef] [Google Scholar]

17. Yamamoto K. Risk of propofol use for sedation in COVID-19 patient. Anaesthesiol Intensive Ther. 2020;52:354–355. doi: 10.5114/ait.2020.100477. [PubMed] [CrossRef] [Google Scholar]

18. Gundry SR. Observational findings of PULS cardiac test findings for inflammatory markers in patients receiving mRNA vaccines. Circulation. 2021;144(suppl_1):A10712–A10712. doi: 10.1161/circ.144.suppl_1.10712. [CrossRef] [Google Scholar]

19. Lai FTT, Li X, Peng K, Huang L, Ip P, Tong X, et al. Carditis After COVID-19 vaccination with a messenger RNA vaccine and an inactivated virus vaccine: a case-control study. Ann Intern Med. 2022;175:362–370. doi: 10.7326/M21-3700. [PMC free article] [PubMed] [CrossRef] [Google Scholar]

COVID-19 alters human genes, explaining mystery behind coronavirus ‘long haulers’

Authors: Chris Melore Published APRIL 28, 2021 Study Finds

For some COVID-19 patients, getting over their infection is just the beginning of the recovery. Over the last year, COVID “long haulers” have continued experiencing a variety of symptoms months after the virus clears. These include anything from skin problems, to shortness of breath, to losing the sense of taste or smell. Now, researchers say they may know why this is happening. A new study finds coronavirus actually causes long-term changes to an infected patient’s genes.

Specifically, scientists reveal the spike protein of SARS-CoV-2, the virus causing COVID-19, creates long-lasting changes to human gene expression. These tiny spikes cover the surface of coronavirus cells. They allow the virus to bind to certain receptors on human cells and hijack their functions — leading to COVID infection. Once the spike cuts into a patient’s cells, the virus releases its own genetic material into the cell so it can replicate.

“We found that exposure to the SARS-CoV-2 spike protein alone was enough to change baseline gene expression in airway cells,” explains Nicholas Evans, a master’s student at the Texas Tech University Health Sciences Center, in a media release. “This suggests that symptoms seen in patients may initially result from the spike protein interacting with the cells directly.”

Spikes make long-term changes to human lung cells

Researchers examined how exposure to spike protein impacts cultured human airway cells in lab experiments. They also compared the results to studies using cell samples from actual COVID-19 patients.

The team notes culturing human airway cells requires time and specific conditions which help the cells mature. This allows the lab cells to develop into the different cells living in a real human airway. To do this, study authors refined a culturing technique called air-liquid interface so they could more closely simulate the conditions in an actual patient’s lungs.

After culturing, scientists exposed the cells to low and high concentrations of purified spike protein. The results reveal differences in gene expression which remained in the cells even after the infection passed. The most affected genes include ones controlling the body’s inflammatory response.

“Our work helps to elucidate changes occurring in patients on the genetic level, which could eventually provide insight into which treatments would work best for specific patients,” Evans explains.

Study authors now plan to use this approach to examine how long these genetic changes last. They also hope to reveal what other long-term consequences a COVID infection will have on a patient’s health.

The team is presenting their findings at Experimental Biology (EB) 2021, a virtual meeting of the American Society for Biochemistry and Molecular Biology.

Worse Than the Disease? Reviewing Some Possible Unintended Consequences of the mRNA Vaccines Against COVID-19

Authors: Stephanie Seneff Computer Science and Artificial Intelligence Laboratory, MIT, Cambridge MA, 02139, USA, Greg Nigh Naturopathic Oncology, Immersion Health, Portland, OR 97214, USA International Journal of Vaccine Theory, Practice, and Research

Abstract

Operation Warp Speed brought to market in the United States two mRNA vaccines, produced by Pfizer and Moderna. Interim data suggested high efficacy for both of these vaccines, which helped legitimize Emergency Use Authorization (EUA) by the FDA. However, the exceptionally rapid movement of these vaccines through controlled trials and into mass deployment raises multiple safety concerns. In this review we first describe the technology underlying these vaccines in detail. We then review both components of and the intended biological response to these vaccines, including production of the spike protein itself, and their potential relationship to a wide range of both acute and long-term induced pathologies, such as blood disorders, neurodegenerative diseases and autoimmune diseases. Among these potential induced pathologies, we discuss the relevance of prion-protein-related amino acid sequences within the spike protein. We also present a brief review of studies supporting the potential for spike protein “shedding”, transmission of the protein from a vaccinated to an unvaccinated person, resulting in symptoms induced in the latter. We finish by addressing a common point of debate, namely, whether or not these vaccines could modify the DNA of those receiving the vaccination. While there are no studies demonstrating definitively that this is happening, we provide a plausible scenario, supported by previously established pathways for transformation and transport of genetic material, whereby injected mRNA could ultimately be incorporated into germ cell DNA for transgenerational transmission. We conclude with our recommendations regarding surveillance that will help to clarify the long-term effects of these experimental drugs and allow us to better assess the true risk/benefit ratio of these novel technologies.

Extensive thrombosis after COVID-19 vaccine: cause or coincidence

Authors: Luís Lourenço Graça ,1 Maria João Amaral ,2 Marco Serôdio,3 Beatriz Costa2

SUMMARY
A 62-year-old Caucasian female patient presented with abdominal pain, vomiting and fever 1 day after administration of COVID-19 vaccine. Bloodwork revealed anaemia and thrombocytosis. Abdominal CT angiography showed a mural thrombus at the emergence of the coeliac trunk, hepatic and splenic arteries, and extensive thrombosis of the superior and inferior mesenteric veins, splenic and portal veins, and the inferior vena cava, extending to the
left common iliac vein. The spleen displayed extensive areas of infarction. Etiological investigation included assessment of congenital coagulation disorders and acquired causes with no relevant findings. Administration of COVID-19 vaccine was considered a possible cause of the extensive multifocal thrombosis. After reviewing relevant literature, it was considered
that other causes of this event should be further investigated. Thrombosis associated with COVID-19vaccine is rare and an etiological relationship should only be considered in the appropriate context and after investigation of other, more frequent, causes.

BACKGROUND
During the COVID-19 pandemic, the pharmaceutical industry is under immense pressure to develop effective and safe vaccines, and as such clinical trials have been expedited in order to make them available to help fight this health crisis. In this context, timely communication between healthcare institutions and regulatory entities is especially important. Reports of thrombosis due to administration of these vaccines have been causing an important
discussion in the scientific community as well as social alarm. However, it is important to note that this is a rare complication and more frequent causes of extensive arterial and venous thrombosis should be considered and investigated.1

CASE PRESENTATION
A 62-year-old Caucasian female patient, with personal history of obesity (body mass index of
30kg/m2), asthma and rhinitis, presented to the emergency department with abdominal pain,
nausea, vomiting and fever (38°C) 1day after administration of the first dose of COVID-19 vaccine(from AstraZeneca). On physical examination, she presented epigastric and left iliac fossa tenderness as the only abnormal finding. The patient denied recent epistaxis and gastrointestinal or genitourinary blood loss.

INVESTIGATIONS
Blood tests revealed microcytic hypochromic anemia (hemoglobin 7g/L), thrombocytosis (780×109/L),increased levels of inflammatory parameters (leucocytes 13×109/L; C reactive protein 31.07mg/dL) and slightly increased levels of liver enzymes and function (AST 36, ALP 126U/L, GGT 72U/L, LDH 441U/L, total bilirubin 1.3mg/dL, direct bilirubin 0.5mg/dL). The patient was tested for COVID-19 with nasopharyngeal PCR tests at admission and on the fifth day of hospitalization. Both tests were negative. Abdominal CT angiography (CTA) showed a mural thrombus at the emergence of the coeliac trunk, with total occlusion (figure 1), as well as at the hepatic and splenic arteries. There was also extensive thrombosis of the superior and inferior mesenteric veins and its tributaries, splenic and portal veins, including the splenoportal confluent (figure 2). There was a filiform thrombus at the distal portion of the inferior vena cava, extending to the left common iliac vein, non-occlusive (figure 3). Spleen presented extensive areas of infarction (figure 1). Coeliac trunk occlusion due to paradoxical embolism was excluded by transthoracic echocardiogram. No interatrial communication was detected. Re-evaluation CTA 5days after the diagnosis was identical. Etiological investigation included assessment of congenital coagulation disorders and acquired causes. Regarding congenital disorders, personal and family history of important thrombotic events, thrombosis in unusual sites and abortions were assessed with no relevant findings. Molecular testing for factor V Leiden mutation and prothrombin gene20210 G/A mutation were both negative. Acquired causes of a coagulation disorder, such as neoplastic, infectious and autoimmune disorders, like antiphospholipid syndrome (APS), were also investigated. Thorax, abdomen, pelvic and brain CT did not detect any suspicious lesions. Tumor biomarkers—carcinoembryonic antigen, alpha fetoprotein, carbohydrate antigen 19-9, cancer antigen 125, cancer antigen 15-3, neuron-specific enolase and chromogranin A—were negative. The patient refused to undergo upper digestive endoscopy and colonoscopy. Despite increased levels of inflammatory parameters at admission (leukocytosis and C reactive protein), these values decreased during the hospitalization period. Blood and urine cultures were also negative. Anticardiolipin IgG and IgM and antibeta-2-glycoprotein IgG and IgM were negative, excluding APS.

DIFFERENTIAL DIAGNOSIS
In the presence of venous and arterial thrombosis, the etiological investigation should include

assessment of congenital and acquired coagulation disorders, as well as the presence of interatrial communication that could explain the coeliac trunk occlusion due to paradoxical embolism. As previously stated, these etiological factors were assessed with no specific findings, with the exception of digestive endoscopic study, which was refused by the patient. In this context, and given the fact that the presentation took place 1day after administration of the first dose of COVID-19 vaccine, we hypothesize that the vaccine might be the cause of the extensive arterial and venous thrombosis. This case was immediately reported to INFARMED, the Portuguese authority for drugs and health products. Vaccine-induced thrombotic thrombocytopenia (VITT) was also considered a differential diagnosis. However, the patient did
not present with thrombocytopenia, which is a key criteria for VITT, and therefore the presence of this syndrome was unlikely.COVID-19 tests at admission and on the fifth day of hospitalization were negative; however, she was not tested prior to the onset of the event and therefore it was not possible to exclude

recent COVID-19 infection, which may predispose to thrombosis, even during the convalescent phase.
TREATMENT
At presentation, there were no signs of organ ischemia that required revascularization procedure or intestinal resection. Considering the anemia, the patient was not a candidate for
fibrinolysis. The treatment was empiric endovenous antibiotherapy and transfusion of two units of red blood cells. Anticoagulation with low molecular weight heparin (LMWH) 1mg/kg
two times per day was initiated and maintained during hospitalisation, with monitoring of anti-Xa levels. After hospitalization,in an outpatient setting, the patient was initiated on edoxaban.

OUTCOME AND FOLLOW-UP
Re-evaluation CTA 28 days after presentation revealed a portal vein with a filiform caliber, with a cavernomatous transformation. There was only permeability of the left branch of the portal
vein, with venous collateralization in the hepatic hilum. Coeliac trunk was still occluded, with permeability of the gastroduodenal artery and the right hepatic artery, and apparent occlusion at the emergence of the left hepatic artery, although with distal repermeabilisation. Partial thrombus persisted in the lumen of the left common iliac vein and inferior infrarenal vena cava. At the follow-up consultation, 1month after discharge, the patient was clinically asymptomatic.

DISCUSSION
Venous and arterial thrombotic disorders have long been considered separate pathophysiological entities due to their anatomical differences and distinct clinical presentations. In particular, arterial thrombosis is seen largely as a phenomenon of platelet
activation, whereas venous thrombosis is mostly a matter of activation of the clotting system.2
There is increasing evidence regarding a link between venous and arterial thromboses. These two vascular complications share several risk factors, such as age, obesity, diabetes mellitus, blood Figure 1 CT angiography arterial phase, axial image: a mural thrombus is observed at the coeliac trunk emergence, with total occlusion. Splenic parenchyma without enhancement after contrast administration can also be observed, translating to extensive infarct areas.
Figure 2 CT angiography portal phase, coronal image: portal vein thrombosis (A) extending to the splenoportal confluent (B) can be observed. Figure 3 CT angiography portal phase, coronal image: a non-occlusive filiform thrombus at the distal portion of the inferior vena cava can be observed, extending to the left common iliac vein. on April 13, 2022 by guest. Protected by copyright. http://casereports.bmj.com/ BMJ Case Rep: first published as 10.1136/bcr-2021-244878 on 16 August 2021. Downloaded from Graça LL, et al. BMJ Case Rep 2021;14:e244878. doi:10.1136/bcr-2021-244878 3

Case report hypertension, hypertriglyceridaemia and metabolic syndrome.3 Moreover, there are many examples of conditions accounting for both venous and arterial thromboses, such as APS, hyperhomocysteinaemia, malignancies, infections and use of hormonal treatment.3 In this case, in accordance with the literature, the patient is 62 years old and obese, with no other findings. Hyperhomocysteinaemia and digestive tract malignancies were not excluded. Recent studies have shown that patients with venous thromboembolism are at a higher risk of arterial thrombotic complications than matched control individuals. Therefore, it is speculated that
the two vascular complications may be simultaneously triggered by biological stimuli responsible for activating coagulation and inflammatory pathways in both the arterial and the venous system.3 The modified adenovirus vector COVID-19 vaccines (ChAdOx1nCoV-19 by Oxford/AstraZeneca and Ad26.COV2.S by Johnson & Johnson/Janssen) and mRNA-based COVID-19 vaccines(BNT162b2 mRNA by Pfizer/BioNTech and mRNA-1273 by Moderna) have shown both safety and efficacy against COVID-19 in phase III clinical trials and are now being used in global vaccination programmes.4Rare cases of postvaccine-associated cerebral venous thrombosis(CVT) from use of COVID-19 vaccines which use a viral vector, including the mechanism of VITT, have emerged in real-worldvaccination.4 On the other hand, the incidence and pathogenesis of CVT after mRNA COVID-19 vaccines remain unknown. However Fan et al4
presented three cases and Dias et al5reported two cases of CVT in patients who took an mRNA vaccine (BNT162b2 mRNA by Pfizer/BioNTech). In both cases, causality has not been proven.
In a recent editorial, three independent descriptions of persons with a newly described syndrome, VITT, were highlighted, characterized by thrombosis and thrombocytopenia that developed 5–24 days after initial vaccination with ChAdOx1 nCoV-19 (AstraZeneca), a recombinant adenoviral vector encoding the spike protein of SARS-CoV-2.6VITT is also characterized by the presence of CVT, thrombosis in the portal, splanchnic and hepatic veins, as well as acute arterial thromboses, platelet counts of 20–30×109 /L, high levels of D-dimers and low levels of fibrinogen, suggesting systemic activation of coagulation.6 In our case, similarities were found with VITT regarding thrombosis in the portal, splanchnic and hepatic veins, as well as acute arterial thromboses and high levels of D-dimers. On the other hand, timing of the event (1day after vaccination), high levels of fibrinogen and absence of thrombocytopenia, which is a key criteria for VITT, point to a different direction. Moreover, the
presence of thrombocytosis allowed for a safe use of LMWH for anticoagulation, with monitoring of anti-Xa levels. Most of the cases reported so far of venous and arterial thrombosis as a complication of AstraZeneca’s COVID-19 vaccine have occurred in women under the age of 60 years, associated with thrombocytopenia, within 2weeks of receiving their first dose of the vaccine.7As for the mechanism, it is thought that the vaccine may trigger an immune response leading to an atypical heparin-induced thrombocytopenia-like disorder. In contrast with the literature, our patient presented with thrombocytosis, not thrombocytopaenia.7 Smadja et al8reported that between 13 December 2020 and
16 March 2021 (94 days), 361734967 people in the international COVID-19 vaccination data set received vaccination and795 venous and 1374 arterial thrombotic events were reported in
Vigibase on 16 March 2021. Spontaneous reports of thrombotic events are shared in 1197 for Pfizer/BioNtech’s COVID-19 vaccine,325 for Moderna’s COVID-19 vaccine and 639 for AstraZeneca’sCOVID-19 vaccine.7 The reporting rate for cases of venous (VTE) and arterial (ATE) thrombotic events during this time period among the total number of people vaccinated was 0.21 cases of thrombotic events per 1million person vaccinated-days.7For VTE and ATE, the rates were 0.075 and 0.13 cases per 1million persons vaccinated, respectively, and the timeframe between vaccinationand ATE is the same for the three vaccines (median of 2days),
although a significant difference in terms of VTE was identified between AstraZeneca’s COVID-19 vaccine (median of 6days) and both mRNA vaccines (median of 4days).8 The first paper addressing this issue was published in the New England Journal of Medicine and described 11 patients, 9 of themwomen.9 Nine patients had cerebral venous thrombosis, three had
splanchnic vein thrombosis, three had pulmonary embolism and four had other thromboses. All 11 patients, as well as another 17 for whom the researchers had blood samples, tested positive for antibodies against platelet factor 4 (PF4). These antibodies are also observed in people who develop heparin-induced thrombocytopenia. However, none of the patients had received heparin before their symptoms started.9Our patient did not present thrombocytopenia, so anti-PF4 antibodies were not tested. Thus, considering the anemia, thrombocytosis and thrombosis diagnosed 1day after the first dose ofCOVID-19 vaccine, it seems prudent to continue investigation for other causes of this event, such as hematological malignancies or others.

REFERENCES
1 Burch J, Enofe I. Acute mesenteric ischaemia secondary to portal, splenic and superior
mesenteric vein thrombosis. BMJ Case Rep 2019;12:e230145.
2 Singer DE, Albers GW, Dalen JE, et al. Antithrombotic therapy in atrial fibrillation:
American College of chest physicians evidence-based clinical practice guidelines (8th
edition). Chest 2008;133:546S–92.
3 Ageno W, Becattini C, Brighton T, et al. Cardiovascular risk factors and venous
thromboembolism: a meta-analysis. Circulation 2008;117:93–102.
4 Fan BE, Shen JY, Lim XR, et al. Cerebral venous thrombosis post BNT162b2 mRNA
SARS-CoV-2 vaccination: a black Swan event. Am J Hematol 2021. doi:10.1002/
ajh.26272. [Epub ahead of print: 16 Jun 2021].
5 Dias L, Soares-Dos-Reis R, Meira J, et al. Cerebral venous thrombosis after BNT162b2
mRNA SARS-CoV-2 vaccine. J Stroke Cerebrovasc Dis 2021;30:105906.
6 Cines DB, Bussel JB. SARS-CoV-2 vaccine-induced immune thrombotic
thrombocytopenia. N Engl J Med 2021;384:2254–6.
7 AstraZeneca’s COVID-19 vaccine: EMA finds possible link to very rare cases of unusual
blood clots with low blood platelets. Available: https://www.ema.europa.eu/en/news/
astrazenecas-covid-19-vaccine-ema-finds-possible-link-very-rare-cases-unusual-bloodclots-low-blood [Accessed Apr 2021].
8 Smadja DM, Yue Q-Y, Chocron R, et al. Vaccination against COVID-19: insight from
arterial and venous thrombosis occurrence using data from VigiBase. Eur Respir J
2021;58:2100956.
9 Wise J. Covid-19: rare immune response may cause clots after AstraZeneca vaccine, say
researchers. BMJ 2021;373:n954.

Intestinal Damage in COVID-19: SARS-CoV-2 Infection and Intestinal Thrombosis

Authors: Xiaoming Wu1Haijiao Jing1Chengyue Wang1Yufeng Wang1Nan Zuo1Tao Jiang2*Valerie A. Novakovic3 and Jialan Shi1,3,4* Front. Microbiol., 22 March 2022 | https://doi.org/10.3389/fmicb.2022.860931

The intestinal tract, with high expression of angiotensin-converting enzyme 2 (ACE2), is a major site of extrapulmonary infection in COVID-19. During pulmonary infection, the virus enters the bloodstream forming viremia, which infects and damages extrapulmonary organs. Uncontrolled viral infection induces cytokine storm and promotes a hypercoagulable state, leading to systemic microthrombi. Both viral infection and microthrombi can damage the gut–blood barrier, resulting in malabsorption, malnutrition, and intestinal flora entering the blood, ultimately increasing disease severity and mortality. Early prophylactic antithrombotic therapy can prevent these damages, thereby reducing mortality. In this review, we discuss the effects of SARS-CoV-2 infection and intestinal thrombosis on intestinal injury and disease severity, as well as corresponding treatment strategies.

Introduction

COVID-19 has become a worldwide pandemic causing widespread illness and mortality. SARS-CoV-2 mainly infects the respiratory tract through attachment to angiotensin-converting enzyme 2 (ACE2) receptors (Lan et al., 2020). ACE2 is also highly expressed on intestinal epithelial cells, allowing SARS-CoV-2 to infect the intestinal tract (Xiao et al., 2020a). Recent meta-analyses show that 48%–54% of fecal samples from COVID-19 patients have tested positive for viral RNA, and 15%–17% of patients have gastrointestinal (GI) symptoms (Cheung et al., 2020Mao et al., 2020Sultan et al., 2020). Additionally, live virus can be isolated from fecal samples of COVID-19 patients (Wang et al., 2020). Some studies have proposed fecal–oral transmission as the cause of intestinal infection (Guo et al., 2021). However, direct evidence for fecal–oral transmission is still lacking. Meanwhile, the virus has been detected in the blood of both symptomatic and asymptomatic patients (Chang et al., 2020), and disseminated virus could infect extrapulmonary organs (Jacobs and Mellors, 2020). Thus, the potential that intestinal infection occurs via blood transmission should be carefully considered.

Pulmonary infection triggers cytokine storm and induces a prothrombotic state (McFadyen et al., 2020Moore and June, 2020). Venous and arterial thrombosis are common in COVID-19 (Moore and June, 2020). Systematic reviews estimate that 14%–31% of in-hospital patients develop a clinically apparent thrombotic event (Suh et al., 2021Tan et al., 2021), while autopsy reports show a high prevalence of microthrombi in multiple organs, including lung, heart, liver, kidney, and gastrointestinal tract (Bradley et al., 2020Polak et al., 2020). A cohort study showed that COVID-19 patients with intestinal ischemia had markedly elevated D-dimer levels and poor outcomes (Norsa et al., 2020). Additionally, recent studies have shown that mesenteric thrombosis often results in intestinal resection and significantly increases mortality (Bhayana et al., 2020El Moheb et al., 2020). Therefore, it is essential to outline the mechanisms of intestinal thrombosis and its contribution to intestinal damage and disease progression.

In this review, we discuss blood transmission as a potential route for intestinal infection. We then summarize the characteristics and mechanism of intestinal thrombosis formation in COVID-19. Next, we focus on the effects of intestinal infection and thrombosis on intestinal damage and disease severity. Finally, we discuss therapeutic strategies to prevent intestinal damage.

Gastrointestinal Symptoms and SARS-CoV-2 Infection

Multiple studies have reported GI symptoms in COVID-19 patients, including diarrhea, nausea, vomiting, anorexia, and abdominal pain (Cheung et al., 2020Mao et al., 2020Sultan et al., 2020). According to a meta-analysis comprising 10,890 COVID-19 patients, the pooled prevalence estimates of GI symptoms were: diarrhea (7.7%), nausea or vomiting (7.8%), and abdominal pain (2.7%; Sultan et al., 2020) with 10% of these patients reporting GI symptoms as being their initial symptoms (Cheung et al., 2020). These data indicate potential gastrointestinal infection by SARS-CoV-2, which is reported to infect and replicate in epithelial cells of human small intestinal organoids (Zang et al., 2020). Both viral nucleocapsid proteins and viral particles have been detected in infected patient intestinal biopsies (Livanos et al., 2021). Additionally, SARS-CoV-2 RNA and live virus can be found in the stool of patients (Wang et al., 2020). More importantly, SARS-CoV-2 subgenomic mRNA is transcribed in actively replicating cells and has been detected in fecal samples (Wölfel et al., 2020). Further, rectal viral shedding persists for longer than that of the respiratory system (Zhao et al., 2020). All these data demonstrate that SARS-CoV-2 directly infects and replicates in intestinal epithelial cells of patients.

Intestinal Infection and Transmission Routes

With the deepening understanding of COVID-19, GI symptoms have been recognized as early signs of the disease. The high expression of ACE2 in the GI tract, isolation of live virus from fecal samples, and a subset of patients presenting with only GI symptoms seem to suggest fecal–oral transmission. However, problems with the feasibility of this mode of transmission remain. First, studies have shown that SARS-CoV-2 loses infectivity in simulated gastric acid within 10 min (Chan et al., 2020Zang et al., 2020Zhong et al., 2020). Secondly, SARS-CoV-2, as an enveloped virus, is largely unable to withstand the detergent effect of bile salts and the activity of digestive enzymes in the duodenum (Figure 1). Although some studies have suggested that highly viscous mucus in the gastrointestinal tract protects SARS-CoV-2, allowing the virus to retain its infectivity (Guo et al., 2021Zhang H. et al., 2021), there is still a lack of direct evidence. Bushman et al. (2019) had previously investigated the links between the structures of viruses and routes of transmission and found a strong association between fecal–oral transmission and the absence of a lipid envelope. Lastly, although some studies have isolated intact viruses from feces (Wang et al., 2020Zhang Y. et al., 2020Zhou et al., 2020Xiao et al., 2020b), most of them have not further confirmed the infectivity of these viruses (Wang et al., 2020Zhang Y. et al., 2020Xiao et al., 2020b). Zhou et al. (2020) confirmed viral propagation by RT-PCR, but only in a single fecal sample. Previous research has shown that SARS-CoV-2 is completely inactivated in simulated human colonic fluid over the course of 24 h, which may explain the sporadic detection of infection-active SARS-CoV-2 from feces samples.FIGURE 1

Figure 1. Intestinal infection and transmission routes. ① Direct evidence for fecal–oral transmission is still lacking. SARS-CoV-2 may be unable to enter the small intestine from the stomach due to gastric acid, bile and digestive enzymes. ② SARS-CoV-2 released from type II alveolar cells infects alveolar capillary endothelial cells (ECs). The virus replicates in ECs and is released into the blood to form viremia. ③ SARS-CoV-2 is released from infected ciliary cells of the nasal cavity and breaks through the basement membrane, infecting the vascular ECs and eventually entering circulation. ④ Blood transmission after alveolar or nasal infection is a potential route of intestinal infection. Eventually, SARS-CoV-2 is released into the gut and infects surrounding intestinal epithelial cells along the intestinal tract. ⑤ SARS-CoV-2 in the gut can also enter the capillaries and cause viremia, leading to recurrence of disease.

Several lines of evidence suggest that SARS-CoV-2 may infect the intestinal tract via the bloodstream. Deng et al. (2020) detected SARS-CoV-2 RNA in anal swabs from intratracheally but not intragastrically infected rhesus macaques, suggesting blood transmission. Indeed, SARS-CoV-2 RNA has been detected in blood and urine samples of patients (Wang et al., 2020). The virus can also be detected in multiple organs (including heart, brain, and kidney) and is associated with organ injury, indicating that the virus can reach and infect extrapulmonary organs (Puelles et al., 2020). Another study showed that SARS-CoV-2 viremia was associated with intestinal damage, independent of disease severity (Li Y. et al., 2021). Thus, blood transmission could be the cause of intestinal infection. Specifically, SARS-CoV-2 replicating in alveolar epithelial cells and capillary ECs is released into the bloodstream and infects new vascular ECs. The capillary network is then the main route by which the virus enters and infects extrapulmonary organs. The extensive surface area of intestinal capillaries makes intestinal epithelial cells more susceptible to infection than other extrapulmonary organs. Following infection of intestinal capillaries, SARS-CoV-2 is released into the gut and infects surrounding intestinal epithelial cells along the intestinal tract (Figure 1). Once established in the gut, SARS-CoV-2 can also reenter the capillaries, potentially leading to recurrence of disease. Consistent with this, in patients who experienced recurrence, the phylogenetic analysis of infection samples has shown that recurrent virus evolves from the original parent virus (Hu et al., 2020).

Additionally, SARS-CoV-2 RNA can also be detected in the blood and urine of asymptomatic patients, suggesting a second pathway to viremia through the nasal cavity (Chang et al., 2020Hasanoglu et al., 2021). The abundant blood vessels, thin mucous membrane, and higher levels of ACE2 (Huang et al., 2021) make it possible for the virus to initiate viremia from the nasal cavity. Specifically, SARS-CoV-2 is released from infected ciliary cells of the nasal cavity and breaks through the basement membrane, infecting the vascular ECs and eventually entering circulation (Figure 1). Blood transmission after nasal infection is therefore another potential route of intestinal infection.

Intestinal Damage, Malnutrition, and Poor Outcomes

A recent study has shown that a fecal sample positive for SARS-CoV-2 RNA at any time during hospitalization was associated with higher mortality [HR: 3.4 (1.2–9.9); Das Adhikari et al., 2021]. Similarly, another study showed that small-bowel thickening on CT was strongly associated with ICU admission (Wölfel et al., 2020). This relationship did not hold for colon or rectal thickening. These data indicates that small-bowel damage contributes to poor outcomes. As the main organ for nutrient absorption, damage to the small intestine will result in malabsorption and malnutrition, both of which commonly occur in COVID-19 patients (Di Filippo et al., 2021Lv et al., 2021) and are associated with disease severity (Luo et al., 2020Zhang P. et al., 2021). A fecal metabolome study showed that feces of COVID-19 patients were enriched with important nutrients that should be metabolized or absorbed, consistent with malabsorption (Lv et al., 2021). A prospective study showed that 29% of COVID-19 patients (31% of hospitalization patients and 21% of patients quarantined at home) had lost >5% of body weight [median weight loss, 6.5 (5.0–9.0) kg or 8.1 (6.1–10.9) %; Di Filippo et al., 2021]. Those patients with weight loss had greater systemic inflammation, impaired renal function and longer disease duration. A large, multicenter study (including 3,229 patients with GI symptoms) showed that 23% of patients had malnutrition, of whom 56.4% were unable to gain weight after 6 months follow-up (Rizvi et al., 2021). Studies also showed that malnutrition was associated with higher incidences of acute respiratory distress syndrome, acute myocardial injury, secondary infection, shock, and 28-day ICU mortality (Luo et al., 2020Zhang P. et al., 2021). Overall, malabsorption and malnutrition due to damaged small intestine increased disease severity and mortality.

Nutrient absorption in the small intestine is mainly through ATP-dependent active transport. Intestinal infection, hypoxemia, and intestinal ischemia contribute to malabsorption. SARS-CoV-2 adhesion depletes ACE2 levels on intestinal epithelial cells, which alters the expression of the neutral amino acid transporter B0AT1, reducing the intake of tryptophan and the production of nicotinamide (D’Amico et al., 2020). Meanwhile, uncontrolled viral replication consumes large amounts of ATP and nutrients, resulting in decreased nutrients entering the bloodstream. More importantly, anaerobic glycolysis caused by hypoxemia and intestinal ischemia significantly decreases ATP and active transport, leading to malabsorption. Additionally, hypoxemia and intestinal ischemia can also cause anorexia, nausea, vomiting, and enteral nutrition intolerance, reducing food intake. A prospective multicenter study showed that reduced food intake was associated with higher ICU admission and mortality (Caccialanza et al., 2021).

Intestinal Ischemia and Thrombosis

Intestinal ischemia is a common manifestation in COVID-19 patients. Autopsy results have shown that 31.6% of deceased patients had focal ischemic intestinal changes (Chiu et al., 2020). In a separate imaging study, bowel wall thickening and pneumatosis intestinalis, which indicate intestinal ischemia, were found on 38.1% (16 of 42) of abdominal CT images (Bhayana et al., 2020). Of these, 4 (9.5%) patients with pneumatosis intestinalis developed severe intestinal necrosis and needed resection. In another cohort study, 55.8% (58/104) of ICU patients developed an ileus (Kaafarani et al., 2020). Although mechanical factors cannot be ruled out, insufficient intestinal motility due to intestinal ischemia was more likely to be the cause of ileus in COVID-19 patients. In these patients with ileus, 4 (3.8%) developed severe intestinal ischemia and require emergency surgery. Both studies found microthrombi in these resected intestinal samples, which were the main cause of intestinal ischemia and increased mortality.

Additional intestinal ischemia and necrosis follows the formation of mesenteric thrombosis. However, there is currently relatively little data of mesenteric thrombus in COVID-19. Therefore, we have summarized the characteristics of 40 patients in 39 case reports published on PubMed (Supplementary Table 1). The median age of these patients was 50 (20–82) years, 26 (65%) were male, 38 (95%) developed bowel ischemia or necrosis, 30 (75%) needed bowel resection, 7 (17.5%) required no surgery, at least 3 (7.5%) developed sepsis, and 13 (32.5%) died. Other abdominal thrombotic events (such as celiac aortic thrombosis) leading to mesenteric ischemia can also result in severe intestinal necrosis and require intestinal resection (Zamboni et al., 2021).

Mild intestinal ischemia can lead to reduced diet and malabsorption. Severe intestinal ischemia or necrosis leads to the dissemination of gut bacteria, endotoxins, and microbial metabolites into the blood (Figure 2 bottom), aggravating hyperinflammation and the hypercoagulability state. Such patients need emergency excision of the necrotic bowel, which significantly increases mortality.FIGURE 2

Figure 2. Intestinal thrombosis leads to intestinal mucosal necrosis and dissemination of gut bacteria, endotoxins, and microbial metabolites in blood. (Top) Mesenteric vascular endotheliitis (initiated by viremia and accelerated by cytokines), hyperactivated platelets and high levels of phosphatidylserine (PS) promote a high rate of mesenteric thrombus in COVID-19 patients (mesenteric vein is shown in Supplementary Figure 1). (Bottom) Intestinal microthrombi and hypoxemia rapidly lead to intestinal mucosal ischemia and necrosis. The damaged gut–blood barrier leads to dissemination of gut bacteria, endotoxins, and microbial metabolites in blood.

Long-Term Gastrointestinal Sequelae

Long-term GI complications are common in recovering COVID-19 patients. In one systematic review of post-acute COVID-19 manifestations, diarrhea was among the top 10 most common complaints, with a prevalence of 6%. Other long-term GI symptoms include nausea, vomiting, abdominal pain, loss of appetite, and weight loss (Aiyegbusi et al., 2021Huang et al., 2021). The exact mechanisms of the GI sequelae remain unclear. Recently, persistent endotheliopathy, higher levels of thrombin (Fogarty et al., 2021), and residual SARS-CoV-2 viral antigens in the GI tract (Cheung et al., 2022) were described in convalescent COVID-19 patients. These data suggest that prolonged intestinal infection, persistent endothelial injury (abnormal intestinal–blood barrier), and microthrombi could be causes of the persistent GI symptoms.

The Mechanisms of Intestinal Thrombosis

Damaged Endothelial Cells

Resected bowel samples from COVID-19 patients routinely exhibit thrombi and endotheliitis, indicating the important role of EC injury in mesenteric thrombosis (Bhayana et al., 2020Chiu et al., 2020Kaafarani et al., 2020). SARS-CoV-2 infection (Varga et al., 2020) and elevated inflammatory cytokines (He et al., 2016) damage mesenteric vascular ECs. In response, EC cell margins retract, extending phosphatidylserine (PS) positive filopods and releasing endothelial microparticles (MPs; Figure 3BHe et al., 2016). The PS+ filopods and MPs can be co-stained by Xa and Va and support fibrin formation (Figures 3BD). The exposed PS then activates tissue factor on ECs, triggering the extrinsic coagulation pathway (Versteeg et al., 2013). Next, higher levels of FVIII and vWF released from damaged EC contribute to the hypercoagulable state and platelet aggregation, respectively (Goshua et al., 2020). Thrombomodulin is then released from ECs in its soluble form, which has an attenuated capacity to activate Protein C due to a lack of other cofactors on ECs, such as endothelial protein C receptor (Versteeg et al., 2013). Finally, upregulation of endothelial cell adhesion molecules recruits neutrophils and platelets and further contributes to thrombosis (Tong et al., 2020Li L. et al., 2021).FIGURE 3

Figure 3. Phosphatidylserine exposure on activated/apoptotic cells and microparticles (MPs) promotes fibrin formation. (A) Phosphatidylserine is usually confined to the inner leaflet of the cell membrane. This asymmetry is maintained through ATP-dependent inward transport of PS by flippases and outward transport of non-PS by floppases (left). Upon stimulation, calcium transients will inhibit ATP-dependent transport and stimulate the nonselective lipid transporter scramblase (ATP-independent), resulting in PS exposure (right). (B–D) Human umbilical vein ECs were treated with healthy human plasma and TNF-ɑ (our previous study; He et al., 2016). (B) ECs retracts the cell margins, extends PS positive filopods and releases endothelial-MPs. (C) The PS+ filopods and MPs can be co-stained by Xa and Va. (D) ECs (green) were incubated with MPs-depleted plasma (MDP) in the presence of calcium for 30 min and stained with Alexa Fluro 647-anti-fibrin for 30 min. Considerable fibrin stands among cultured ECs along with filopodia. (E) Confocal images showed PS expression on platelets of patients stained with Alexa 488 lactadherin (our previous study; Ma et al., 2017). MPs from the activated platelet (*) had formed at the margin area located between the distinct outlines. (F) MPs from plasma were co-stained by Xa and Va (or lactadherin and annexin V; our previous study; Gao et al., 2015). (G) MPs that were incubated with recalcified MDP for 30 min and stained with Alexa Fluro 647-anti-fibrin for 30 min. Converted fibrin networks were detected around MPs. The inset bars represent 5 μm in (B–D,G) and 2 μm in (E,F).

Hyperactivated Platelets and Phosphatidylserine Storm

Although COVID-19 patients exhibit mild thrombocytopenia, the remaining platelets are hyperactivated (Manne et al., 2020Taus et al., 2020Zaid et al., 2020). Studies have shown that platelets from COVID-19 patients have increased P-selectin and αIIbβ3 expression. P-selectin on activated platelets interacts with integrin αIIb3 on monocytes to form platelet-monocyte complexes, which induce monocyte tissue factor expression (Hottz et al., 2020). The activated platelets can also induce neutrophils to release neutrophil extracellular traps (NETs; Middleton et al., 2020). Furthermore, platelets from COVID-19 patients aggregate and adhere more efficiently to collagen-coated surfaces under flow conditions (Manne et al., 2020Zaid et al., 2020). Meanwhile, activated platelets release α- and dense-granule contents including FV, FXI, fibrinogen and vWF (Zaid et al., 2020). In addition, activated platelets also produce inflammatory cytokines, fueling cytokine storm (Taus et al., 2020Zaid et al., 2020). Most importantly, activated platelets expose higher levels of PS and release higher numbers of PS+ MPs (Figures 3EGZaid et al., 2020Althaus et al., 2021).

Phosphatidylserine is the most abundant negatively charged phospholipid in mammalian cells and is usually confined to the inner leaflet of the cell membrane (Versteeg et al., 2013). This asymmetry is maintained through ATP-dependent inward transport of PS by flippases and outward transport of other phospholipids by floppases (Figure 3A left). Upon stimulation, transiently increased calcium inhibits ATP-dependent transport and stimulates the nonselective lipid transporter scramblase (ATP-independent), resulting in PS exposure on the outer membrane (Figure 3A right). During this process, microvesicles derived from the budding of cellular membranes will be released. These MPs are typically <1 μm and express PS (Burnier et al., 2009). The exposure of PS on the surface of cells and MPs provides a catalytic surface for factor Xa and thrombin formation in vivo (Versteeg et al., 2013). We have previously demonstrated that PS mediates 90% of Xa and thrombin formation and significantly increases thrombosis in vivo (Shi and Gilbert, 2003).

Cytokines and virus infection can activate blood cells and ECs, resulting in higher levels of PS+ cells and MPs. As COVID-19 progresses, the developing cytokine storm activates more blood cells, leading to PS storm. Platelets are highly sensitive to circulating cytokines, releasing large amounts of cytokines and PS exposed MPs into the plasma (Taus et al., 2020Althaus et al., 2021) and thus are a major contributor to PS storm. Previous studies found an unusual elevation of FVa in severe COVID-19 patients (248 IU/dl, higher than any previous disease; Stefely et al., 2020von Meijenfeldt et al., 2021). The degree of FVa elevation in these patients may be the result of PS storm.

Collectively, SARS-CoV-2 infection is the initiating factor for injury of the intestinal vascular ECs, which is then aggravated by systemic cytokines, leading to endotheliitis. Subsequently, the hyperactivated platelets in circulation rapidly accumulate around the damaged ECs, inducing tissue factor expression, NET release, and activating the intrinsic/extrinsic coagulation pathways. Simultaneously, the high levels of PS expression in circulating cells and MPs further promote thrombin and fibrin formation (Figure 2 top).

Early Antithrombotic Treatment

Vaccines and antithrombotic therapy are effective measures to reduce intestinal damage and fight against the COVID-19 pandemic (Baden et al., 2021Chalmers et al., 2021). Vaccines induce adaptive immunity to clear the virus, reducing intestinal infection and intestinal damage. However, the usefulness of vaccines is limited by incomplete vaccine acceptance and viral mutations (Hacisuleyman et al., 2021Wang et al., 2021). Vaccines are also ineffective for already infected patients. Therefore, more attention should be paid to antithrombotic therapy. Studies had shown that thrombotic events mainly occurred within 7 days of COVID-19 diagnosis (both inpatients and outpatients; Mouhat et al., 2020Ho et al., 2021). Meanwhile, two large randomized controlled trials (RCTs) from the same platform showed that therapeutic anticoagulation reduced mortality in moderate cases but not in severe ones, suggesting that delayed anticoagulant therapy may lead to treatment failure (REMAP-CAP Investigators et al., 2021a,b). More importantly, a recent study reported three asymptomatic COVID-19 patients who developed abdominal (or intestinal) thrombosis leading to intestinal necrosis (Zamboni et al., 2021). All these data suggest that antithrombotic therapy should be initiated once COVID-19 is diagnosed (excluding patients with contraindications). Early prophylactic antithrombotic therapy can reduce the activation of vascular ECs and blood cells, preventing intestinal thrombosis, ensuring sufficient intestinal perfusion, maintaining the normal gut–blood barrier, avoiding malabsorption, malnutrition, and intestinal flora entering the bloodstream. Further, attenuated injury and decreased microthrombi in convalescent patients may lower the risk of long-term GI sequelae. Meanwhile, unobstructed systemic circulation can also accelerate the removal of SARS-CoV-2, inflammatory cytokines and damaged blood cells by the mononuclear phagocyte system.

Anticoagulation

Table 1 summarizes the RCTs of anticoagulant therapy in COVID-19 patients. For outpatients, early anticoagulant therapy reduced hospitalization and supplemental oxygen (Gonzalez-Ochoa). While, delayed treatment had no similar effect (ACTIV-4B and Ananworanich). Thus, oral anticoagulant therapy should be initiated in outpatients once COVID-19 is diagnosed. For non-critically ill patients, therapeutic doses of low molecular weight heparin (LMWH) reduced thrombotic events and mortality, and increased organ support-free days (REMAP-CAP, ACTIV-4a, ATTACC; RAPID; HEP-COVID). However, therapeutic doses of rivaroxaban did not improve clinical outcomes and increased bleeding (ACTION). This is potentially because novel oral anticoagulants do not share the anti-inflammatory and antiviral functions of heparin. Intestinal damage might also result in abnormal absorption of oral anticoagulants. Therefore, therapeutic LMWH should be the first choice for non-critically ill patients. For critically ill patients, RCTs showed that moderate and therapeutic doses were not superior to prophylactic ones. Results from several other studies suggest that the overwhelming thrombosis leads to failure of anticoagulant therapy at therapeutic doses (Leentjens et al., 2021Poor, 2021). Faced with this dilemma, an editorial in N Engl J Med argued that profibrinolytic strategies should be considered (Ten Cate, 2021). More studies are needed to explore optimal antithrombotic therapy in critically ill patients.TABLE 1

Table 1. Randomized clinical trials of anticoagulant therapy in COVID-19 patients.

Inhibition of Platelet Activation

As COVID-19 progresses, cytokine storm activates platelets, which not only participate in primary hemostasis, but also are the major components of PS storm. Autopsy results show a high prevalence of platelet-fibrin-rich microthrombi in lung and extrapulmonary organs, including the gastrointestinal tract (Bradley et al., 2020Polak et al., 2020). Early inhibition of platelet activation can reduce platelet activity and prevent PS storm, thus decreasing thrombosis and mortality. Several observational studies have shown that aspirin decreases mechanical ventilation, ICU admission, and mortality (Chow et al., 2020Santoro et al., 2022). The RCTs testing antiplatelet agents were still preliminary. A recent RCT suggested that aspirin was associated with an increase in survival and reduction in thrombotic events (RECOVERY Collaborative Group, 2022). In addition, anti-inflammatory therapy (e.g., dexamethasone, 6 mg once daily; RECOVERY Collaborative Group et al., 2020) inhibits cytokine storm, as well as platelet activation, reducing mortality. Overall, inhibition of platelet activation is also important to reduce mortality through the prevention of thrombosis and organs damage.

Factors Influencing Antithrombotic Treatment

Thrombotic Risk Factors or Co-morbidities

Studies have shown that obesity, hyperglycemia and diabetes are associated with increased thrombotic events (including intestinal thrombosis), COVID-19 severity, and mortality (Drucker, 2021Stefan et al., 2021). Other thrombotic risk factors include previous venous thromboembolism, active cancer, known thrombophilic condition, recent trauma or surgery, age ≥70 years, respiratory/cardiac/renal failure, and inflammatory bowel disease (Susen et al., 2020). These factors or co-morbidities heighten basal inflammatory levels and endothelial damage, leading to premature cytokine and PS storms, ultimately increasing thrombosis and mortality. Thus, more active antithrombotic therapy strategies should be adopted in these patients. For patients with mild COVID-19 with these factors, the French Working Group on Perioperative Hemostasis and the French Study Group on Thrombosis and Hemostasis recommend higher (intermediate) doses of anticoagulant therapy (Susen et al., 2020). For moderately ill patients, therapeutic doses of anticoagulant therapy should be initiated as soon as possible to prevent excessive microthrombus formation. The need for extended thromboprophylaxis in discharged patients remains controversial. However, a recent RCT showed that rivaroxaban (10 mg/day, 35 days) improved clinical outcomes in discharged COVID-19 patients with higher thrombotic risk factors (Ramacciotti et al., 2022), supporting extended thromboprophylaxis in patients with these risk factors or co-morbidities.

Vaccination

Although more than half the world population has received at least one dose of the vaccines, there are relatively little data of antithrombotic therapy in vaccinated patients. Studies of viral dynamics show that the viral loads of vaccinated patients are as high as that of unvaccinated patients, but drop significantly faster (Brown et al., 2021Klompas, 2021). Thus, vaccinated patients have shorter hospital stays, and are less likely to progress to critical illness and death (Tenforde et al., 2021Thompson et al., 2021). Nevertheless, antithrombotic therapy is still beneficial for the vaccinated patients. Firstly, heparin has anti-inflammatory and antiviral functions and can interfere with the binding of SARS-CoV-2 to ACE2 and shorten the duration of virus infection (Kwon et al., 2020Pereyra et al., 2021). Secondly, antithrombotic therapy protects cells from damage, PS exposure, and microthrombi formation, maintains unobstructed blood circulation, and facilitates virus clearance (by vaccine-induced adaptive immunity). Thirdly, thrombosis remains an important factor in disease progression. Antithrombotic therapy further reduces thrombosis and mortality, especially in vaccinated patients with high risk factors or co-morbidities. Lastly, although vaccines reduce the incidence, a subset of vaccinated patients will still develop long-term sequelae or Long Covid (Ledford, 2021Antonelli et al., 2022). Persistent viral infection and microthrombi are the primary causes (Ledford, 2021Xie et al., 2022), and early antithrombotic therapy is still needed to prevent them.

Conclusion and Future Research

During COVID-19 disease progression, SARS-CoV-2 infiltrates the blood stream from the initial respiratory tract infection, causing viremia, hyperactivated platelets and PS storm. The virus settles into the vascular beds of extrapulmonary organs, ultimately causing infection of intestinal epithelial cell. Damaged ECs, combined with hyperactivated platelets and PS storm, promote intestinal thrombosis, resulting in intestinal ischemia or necrosis. The damaged gut–blood barrier leads to malabsorption, malnutrition and intestinal flora entering the bloodstream, which significantly increase disease severity and mortality. Prolonged intestinal infection, persistent endothelial injury and microthrombi contribute to the long-term GI sequelae after discharge. Early prophylactic antithrombotic therapy can prevent microthrombi, ensuring sufficient intestinal perfusion, maintaining the normal intestinal function, and reducing the risk of long-term GI sequelae. More active antithrombotic therapy should be adopted in patients with other thrombotic risk factors or co-morbidities. Even in vaccinated COVID-19 patients, antithrombotic therapy is also important to decrease (intestinal) thrombosis, mortality and the risk of long-term GI sequelae.

With the Omicron pandemic, patients requiring hospitalization and ICU treatment decline rapidly. However, people are increasingly concerned about Long Covid. In terms of long-term GI sequelae, the detailed mechanisms of prolonged intestinal infection and persistent microthrombi remain unclear. And whether anticoagulant therapy can decrease GI symptoms in patients with long-term GI sequelae deserves further study. Finally, the impact of vaccines on long-term GI sequelae remains unclear in previously infected and breakthrough infected patients.

References

Aiyegbusi, O. L., Hughes, S. E., Turner, G., Rivera, S. C., McMullan, C., Chandan, J. S., et al. (2021). Symptoms, complications and management of long COVID: a review. J. R. Soc. Med. 114, 428–442. doi: 10.1177/01410768211032850

PubMed Abstract | CrossRef Full Text | Google Scholar

Althaus, K., Marini, I., Zlamal, J., Pelzl, L., Singh, A., Häberle, H., et al. (2021). Antibody-induced procoagulant platelets in severe COVID-19 infection. Blood 137, 1061–1071. doi: 10.1182/blood.2020008762

PubMed Abstract | CrossRef Full Text | Google Scholar

Ananworanich, J., Mogg, R., Dunne, M. W., Bassyouni, M., David, C. V., Gonzalez, E., et al. (2021). Randomized study of rivaroxaban vs. placebo on disease progression and symptoms resolution in high-risk adults with mild COVID-19. Clin. Infect. Dis. doi: 10.1093/cid/ciab813 [Epub ahead of print].

PubMed Abstract | CrossRef Full Text | Google Scholar

Antonelli, M., Penfold, R. S., Merino, J., Sudre, C. H., Molteni, E., Berry, S., et al. (2022). Risk factors and disease profile of post-vaccination SARS-CoV-2 infection in UK users of the COVID symptom study app: a prospective, community-based, nested, case-control study. Lancet Infect. Dis. 22, 43–55. doi: 10.1016/S1473-3099(21)00460-6

CrossRef Full Text | Google Scholar

Baden, L. R., El Sahly, H. M., Essink, B., Kotloff, K., Frey, S., Novak, R., et al. (2021). Efficacy and safety of the mRNA-1273 SARS-CoV-2 vaccine. N. Engl. J. Med. 384, 403–416. doi: 10.1056/NEJMoa2035389

CrossRef Full Text | Google Scholar

Bhayana, R., Som, A., Li, M. D., Carey, D. E., Anderson, M. A., Blake, M. A., et al. (2020). Abdominal imaging findings in COVID-19: preliminary observations. Radiology 297, E207–E215. doi: 10.1148/radiol.2020201908

PubMed Abstract | CrossRef Full Text | Google Scholar

Bradley, B. T., Maioli, H., Johnston, R., Chaudhry, I., Fink, S. L., Xu, H., et al. (2020). Histopathology and ultrastructural findings of fatal COVID-19 infections in Washington state: a case series. Lancet 396, 320–332. doi: 10.1016/S0140-6736(20)31305-2

PubMed Abstract | CrossRef Full Text | Google Scholar

Brown, C. M., Vostok, J., Johnson, H., Burns, M., Gharpure, R., Sami, S., et al. (2021). Outbreak of SARS-CoV-2 infections, including COVID-19 vaccine breakthrough infections, associated with large public gatherings – Barnstable County, Massachusetts, July 2021. MMWR Morb. Mortal. Wkly Rep. 70, 1059–1062. doi: 10.15585/mmwr.mm7031e2

PubMed Abstract | CrossRef Full Text | Google Scholar

Burnier, L., Fontana, P., Kwak, B. R., and Angelillo-Scherrer, A. (2009). Cell-derived microparticles in haemostasis and vascular medicine. Thromb. Haemost. 101, 439–451. doi: 10.1160/TH08-08-0521

CrossRef Full Text | Google Scholar

Bushman, F. D., McCormick, K., and Sherrill-Mix, S. (2019). Virus structures constrain transmission modes. Nat. Microbiol. 4, 1778–1780. doi: 10.1038/s41564-019-0523-5

PubMed Abstract | CrossRef Full Text | Google Scholar

Caccialanza, R., Formisano, E., Klersy, C., Ferretti, V., Ferrari, A., Demontis, S., et al. (2021). Nutritional parameters associated with prognosis in non-critically ill hospitalized COVID-19 patients: the NUTRI-COVID19 study. Clin. Nutr. doi: 10.1016/j.clnu.2021.06.020 [Epub ahead of print].

CrossRef Full Text | Google Scholar

Chalmers, J. D., Crichton, M. L., Goeminne, P. C., Cao, B., Humbert, M., Shteinberg, M., et al. (2021). Management of hospitalised adults with coronavirus disease 2019 (COVID-19): a European Respiratory Society living guideline. Eur. Respir. J. 57:2100048. doi: 10.1183/13993003.00048-2021

PubMed Abstract | CrossRef Full Text | Google Scholar

Chan, K. H., Sridhar, S., Zhang, R. R., Chu, H., Fung, A. Y., Chan, G., et al. (2020). Factors affecting stability and infectivity of SARS-CoV-2. J. Hosp. Infect. 106, 226–231. doi: 10.1016/j.jhin.2020.07.009

CrossRef Full Text | Google Scholar

Chang, L., Zhao, L., Gong, H., Wang, L., and Wang, L. (2020). Severe acute respiratory syndrome coronavirus 2 RNA detected in blood donations. Emerg. Infect. Dis. 26, 1631–1633. doi: 10.3201/eid2607.200839

PubMed Abstract | CrossRef Full Text | Google Scholar

Cheung, C. C. L., Goh, D., Lim, X., Tien, T. Z., Lim, J. C. T., Lee, J. N., et al. (2022). Residual SARS-CoV-2 viral antigens detected in GI and hepatic tissues from five recovered patients with COVID-19. Gut 71, 226–229. doi: 10.1136/gutjnl-2021-324280

PubMed Abstract | CrossRef Full Text | Google Scholar

Cheung, K. S., Hung, I. F. N., Chan, P. P. Y., Lung, K. C., Tso, E., Liu, R., et al. (2020). Gastrointestinal manifestations of SARS-CoV-2 infection and virus load in faecal samples from a Hong Kong cohort: systematic review and meta-analysis. Gastroenterology 159, 81–95. doi: 10.1053/j.gastro.2020.03.065

CrossRef Full Text | Google Scholar

Chiu, C. Y., Sarwal, A., Mon, A. M., Tan, Y. E., and Shah, V. (2020). Gastrointestinal: COVID-19 related ischemic bowel disease. J. Gastroenterol. Hepatol. 36:850. doi: 10.1111/jgh.15254

PubMed Abstract | CrossRef Full Text | Google Scholar

Chow, J. H., Khanna, A. K., Kethireddy, S., Yamane, D., Levine, A., Jackson, A. M., et al. (2020). Aspirin use is associated with decreased mechanical ventilation, ICU admission, and in-hospital mortality in hospitalized patients with COVID-19. Anesth. Analg. 132, 930–941. doi: 10.1213/ANE.0000000000005292

CrossRef Full Text | Google Scholar

Connors, J. M., Brooks, M. M., Sciurba, F. C., Krishnan, J. A., Bledsoe, J. R., Kindzelski, A., et al. (2021). Effect of antithrombotic therapy on clinical outcomes in outpatients with clinically stable symptomatic COVID-19: the ACTIV-4B randomized clinical trial. JAMA 326, 1703–1712. doi: 10.1001/jama.2021.17272

PubMed Abstract | CrossRef Full Text | Google Scholar

D’Amico, F., Baumgart, D. C., Danese, S., and Peyrin-Biroulet, L. (2020). Diarrhea during COVID-19 infection: pathogenesis, epidemiology, prevention, and management. Clin. Gastroenterol. Hepatol. 18, 1663–1672. doi: 10.1016/j.cgh.2020.04.001

PubMed Abstract | CrossRef Full Text | Google Scholar

Das Adhikari, U., Eng, G., Farcasanu, M., Avena, L. E., Choudhary, M. C., Triant, V. A., et al. (2021). Faecal SARS-CoV-2 RNA is associated with decreased COVID-19 survival. Clin. Infect. Dis. doi: 10.1093/cid/ciab623 Epub ahead of print

PubMed Abstract | CrossRef Full Text | Google Scholar

Deng, W., Bao, L., Gao, H., Xiang, Z., Qu, Y., Song, Z., et al. (2020). Ocular conjunctival inoculation of SARS-CoV-2 can cause mild COVID-19 in rhesus macaques. Nat. Commun. 11:4400. doi: 10.1038/s41467-020-18149-6

CrossRef Full Text | Google Scholar

Di Filippo, L., De Lorenzo, R., D’Amico, M., Sofia, V., Roveri, L., Mele, R., et al. (2021). COVID-19 is associated with clinically significant weight loss and risk of malnutrition, independent of hospitalisation: a post-hoc analysis of a prospective cohort study. Clin. Nutr. 40, 2420–2426. doi: 10.1016/j.clnu.2020.10.043

PubMed Abstract | CrossRef Full Text | Google Scholar

Drucker, D. J. (2021). Diabetes, obesity, metabolism, and SARS-CoV-2 infection: the end of the beginning. Cell Metab. 33, 479–498. doi: 10.1016/j.cmet.2021.01.016

CrossRef Full Text | Google Scholar

El Moheb, M., Naar, L., Christensen, M. A., Kapoen, C., Maurer, L. R., Farhat, M., et al. (2020). Gastrointestinal complications in critically ill patients with and without COVID-19. JAMA 324, 1899–1901. doi: 10.1001/jama.2020.19400

PubMed Abstract | CrossRef Full Text | Google Scholar

Fogarty, H., Townsend, L., Morrin, H., Ahmad, A., Comerford, C., Karampini, E., et al. (2021). Persistent endotheliopathy in the pathogenesis of long COVID syndrome. J. Thromb. Haemost. 19, 2546–2555. doi: 10.1111/jth.15490

CrossRef Full Text | Google Scholar

Gao, C., Xie, R., Yu, C., Ma, R., Dong, W., Meng, H., et al. (2015). Thrombotic role of blood and endothelial cells in uremia through phosphatidylserine exposure and microparticle release. PLoS One 10:e0142835. doi: 10.1371/journal.pone.0142835

PubMed Abstract | CrossRef Full Text | Google Scholar

Gonzalez-Ochoa, A. J., Raffetto, J. D., Hernández, A. G., Zavala, N., Gutiérrez, O., Vargas, A., et al. (2021). Sulodexide in the treatment of patients with early stages of COVID-19: a randomized controlled trial. Thromb. Haemost. 121, 944–954. doi: 10.1055/a-1414-5216

CrossRef Full Text | Google Scholar

Goshua, G., Pine, A. B., Meizlish, M. L., Chang, C. H., Zhang, H., Bahel, P., et al. (2020). Endotheliopathy in COVID-19-associated coagulopathy: evidence from a single-Centre, cross-sectional study. Lancet Haematol. 7, e575–e582. doi: 10.1016/S2352-3026(20)30216-7

CrossRef Full Text | Google Scholar

Guo, M., Tao, W., Flavell, R. A., and Zhu, S. (2021). Potential intestinal infection and faecal-oral transmission of SARS-CoV-2. Nat. Rev. Gastroenterol. Hepatol. 18, 269–283. doi: 10.1038/s41575-021-00416-6

CrossRef Full Text | Google Scholar

Hacisuleyman, E., Hale, C., Saito, Y., Blachere, N. E., Bergh, M., Conlon, E. G., et al. (2021). Vaccine breakthrough infections with SARS-CoV-2 variants. N. Engl. J. Med. 384, 2212–2218. doi: 10.1056/NEJMoa2105000

CrossRef Full Text | Google Scholar

Hasanoglu, I., Korukluoglu, G., Asilturk, D., Cosgun, Y., Kalem, A. K., Altas, A. B., et al. (2021). Higher viral loads in asymptomatic COVID-19 patients might be the invisible part of the iceberg. Infection 49, 117–126. doi: 10.1007/s15010-020-01548-8

PubMed Abstract | CrossRef Full Text | Google Scholar

He, Z., Si, Y., Jiang, T., Ma, R., Zhang, Y., Cao, M., et al. (2016). Phosphotidylserine exposure and neutrophil extracellular traps enhance procoagulant activity in patients with inflammatory bowel disease. Thromb. Haemost. 115, 738–751. doi: 10.1160/TH15-09-0710

CrossRef Full Text | Google Scholar

Ho, F. K., Man, K. K. C., Toshner, M., Church, C., Celis-Morales, C., Wong, I. C. K., et al. (2021). Thromboembolic risk in hospitalized and nonhospitalized COVID-19 patients: a self-controlled case series analysis of a nationwide cohort. Mayo Clin. Proc. 96, 2587–2597. doi: 10.1016/j.mayocp.2021.07.002

PubMed Abstract | CrossRef Full Text | Google Scholar

Hottz, E. D., Azevedo-Quintanilha, I. G., Palhinha, L., Teixeira, L., Barreto, E. A., Pão, C. R. R., et al. (2020). Platelet activation and platelet-monocyte aggregates formation trigger tissue factor expression in severe COVID-19 patients. Blood 136, 1330–1341. doi: 10.1182/blood.2020007252

PubMed Abstract | CrossRef Full Text | Google Scholar

Hu, F., Chen, F., Ou, Z., Fan, Q., Tan, X., Wang, Y., et al. (2020). A compromised specific Humoral immune response against the SARS-CoV-2 receptor-binding domain is related to viral persistence and periodic shedding in the gastrointestinal tract. Cell. Mol. Immunol. 17, 1119–1125. doi: 10.1038/s41423-020-00550-2

CrossRef Full Text | Google Scholar

Huang, N., Pérez, P., Kato, T., Mikami, Y., Okuda, K., Gilmore, R. C., et al. (2021). SARS-CoV-2 infection of the oral cavity and saliva. Nat. Med. 27, 892–903. doi: 10.1038/s41591-021-01296-8

PubMed Abstract | CrossRef Full Text | Google Scholar

INSPIRATION Investigators Sadeghipour, P., Talasaz, A. H., Rashidi, F., Sharif-Kashani, B., Beigmohammadi, M. T., et al. (2021). Effect of intermediate-dose vs. standard-dose prophylactic anticoagulation on thrombotic events, extracorporeal membrane oxygenation treatment, or mortality among patients with COVID-19 admitted to the intensive care unit: the INSPIRATION randomized clinical trial. JAMA 325, 1620–1630. doi: 10.1001/jama.2021.4152

PubMed Abstract | CrossRef Full Text | Google Scholar

Jacobs, J. L., and Mellors, J. W. (2020). Detection of SARS-CoV-2 RNA in blood of patients with COVID-19: what does it mean? Clin. Infect. Dis. doi: 10.1093/cid/ciaa1316 [Epub ahead of print].

CrossRef Full Text | Google Scholar

Kaafarani, H. M. A., El Moheb, M., Hwabejire, J. O., Naar, L., Christensen, M. A., Breen, K., et al. (2020). Gastrointestinal complications in critically ill patients with COVID-19. Ann. Surg. 272, e61–e62. doi: 10.1097/SLA.0000000000004004

CrossRef Full Text | Google Scholar

Klompas, M. (2021). Understanding breakthrough infections following mRNA SARS-CoV-2 vaccination. JAMA 326, 2018–2020. doi: 10.1001/jama.2021.19063

PubMed Abstract | CrossRef Full Text | Google Scholar

Kwon, P. S., Oh, H., Kwon, S. J., Jin, W., Zhang, F., Fraser, K., et al. (2020). Sulfated polysaccharides effectively inhibit SARS-CoV-2 in vitro. Cell Discov. 6:50. doi: 10.1038/s41421-020-00192-8

PubMed Abstract | CrossRef Full Text | Google Scholar

Lan, J., Ge, J., Yu, J., Shan, S., Zhou, H., Fan, S., et al. (2020). Structure of the SARS-CoV-2 spike receptor-binding domain bound to the ACE2 receptor. Nature 581, 215–220. doi: 10.1038/s41586-020-2180-5

CrossRef Full Text | Google Scholar

Ledford, H. (2021). Do vaccines protect against long COVID? What the data say. Nature 599, 546–548. doi: 10.1038/d41586-021-03495-2

CrossRef Full Text | Google Scholar

Leentjens, J., van Haaps, T. F., Wessels, P. F., Schutgens, R. E. G., and Middeldorp, S. (2021). COVID-19-associated coagulopathy and antithrombotic agents-lessons after 1 year. Lancet Haematol. 8, e524–e533. doi: 10.1016/S2352-3026(21)00105-8

PubMed Abstract | CrossRef Full Text | Google Scholar

Lemos, A. C. B., do Espírito Santo, D. A., Salvetti, M. C., Gilio, R. N., Agra, L. B., Pazin-Filho, A., et al. (2020). Therapeutic versus prophylactic anticoagulation for severe COVID-19: a randomized phase II clinical trial (HESACOVID). Thromb. Res. 196, 359–366. doi: 10.1016/j.thromres.2020.09.026

PubMed Abstract | CrossRef Full Text | Google Scholar

Li, L., Huang, M., Shen, J., Wang, Y., Wang, R., Yuan, C., et al. (2021). Serum levels of soluble platelet endothelial cell adhesion molecule 1 in COVID-19 patients are associated with disease severity. J. Infect. Dis. 223, 178–179. doi: 10.1093/infdis/jiaa642

PubMed Abstract | CrossRef Full Text | Google Scholar

Li, Y., Schneider, A. M., Mehta, A., Sade-Feldman, M., Kays, K. R., Gentili, M., et al. (2021). SARS-CoV-2 viremia is associated with distinct proteomic pathways and predicts COVID-19 outcomes. J. Clin. Invest. 131:e148635. doi: 10.1172/JCI148635

CrossRef Full Text | Google Scholar

Livanos, A. E., Jha, D., Cossarini, F., Gonzalez-Reiche, A. S., Tokuyama, M., Aydillo, T., et al. (2021). Intestinal host response to SARS-CoV-2 infection and COVID-19 outcomes in patients with gastrointestinal symptoms. Gastroenterology 16, 2435.e34–2450.e34. doi: 10.1053/j.gastro.2021.02.056

CrossRef Full Text | Google Scholar

Lopes, R. D., de Barros, E., Silva, P. G. M., Furtado, R. H. M., Macedo, A. V. S., Bronhara, B., et al. (2021). Therapeutic versus prophylactic anticoagulation for patients admitted to hospital with COVID-19 and elevated D-dimer concentration (ACTION): an open-label, multicentre, randomised, controlled trial. Lancet 397, 2253–2263. doi: 10.1016/S0140-6736(21)01203-4

CrossRef Full Text | Google Scholar

Luo, Y., Xue, Y., Mao, L., Yuan, X., Lin, Q., Tang, G., et al. (2020). Prealbumin as a predictor of prognosis in patients with coronavirus disease 2019. Front. Med. 7:374. doi: 10.3389/fmed.2020.00374

PubMed Abstract | CrossRef Full Text | Google Scholar

Lv, L., Jiang, H., Chen, Y., Gu, S., Xia, J., Zhang, H., et al. (2021). The faecal metabolome in COVID-19 patients is altered and associated with clinical features and gut microbes. Anal. Chim. Acta 1152:338267. doi: 10.1016/j.aca.2021.338267

PubMed Abstract | CrossRef Full Text | Google Scholar

Ma, R., Xie, R., Yu, C., Si, Y., Wu, X., Zhao, L., et al. (2017). Phosphatidylserine-mediated platelet clearance by endothelium decreases platelet aggregates and procoagulant activity in sepsis. Sci. Rep. 7:4978. doi: 10.1038/s41598-018-24187-4

PubMed Abstract | CrossRef Full Text | Google Scholar

Manne, B. K., Denorme, F., Middleton, E. A., Portier, I., Rowley, J. W., Stubben, C., et al. (2020). Platelet gene expression and function in patients with COVID-19. Blood 136, 1317–1329. doi: 10.1182/blood.2020007214

PubMed Abstract | CrossRef Full Text | Google Scholar

Mao, R., Qiu, Y., He, J. S., Tan, J. Y., Li, X. H., Liang, J., et al. (2020). Manifestations and prognosis of gastrointestinal and liver involvement in patients with COVID-19: a systematic review and meta-analysis. Lancet Gastroenterol. Hepatol. 5, 667–678. doi: 10.1016/S2468-1253(20)30126-6

PubMed Abstract | CrossRef Full Text | Google Scholar

Marcos-Jubilar, M., Carmona-Torre, F., Vidal Laso, R., Ruiz-Artacho, P., Filella, D., Carbonell, C., et al. (2022). Therapeutic versus prophylactic bemiparin in hospitalized patients with non-severe COVID-19 pneumonia (BEMICOP): an open-label, multicenter, randomized trial. Thromb. Haemost. 122, 295–299. doi: 10.1055/a-1667-7534

PubMed Abstract | CrossRef Full Text | Google Scholar

McFadyen, D. J., Stevens, H., and Karlheinz, P. (2020). The emerging threat of (micro)thrombosis in COVID-19 and its therapeutic implications. Circ. Res. 127, 571–587. doi: 10.1161/CIRCRESAHA.120.317447

CrossRef Full Text | Google Scholar

Middleton, E. A., He, X. Y., Denorme, F., Campbell, R. A., Ng, D., Salvatore, S. P., et al. (2020). Neutrophil extracellular traps contribute to immunothrombosis in COVID-19 acute respiratory distress syndrome. Blood 136, 1169–1179. doi: 10.1182/blood.2020007008

CrossRef Full Text | Google Scholar

Moore, J. B., and June, C. H. (2020). Cytokine release syndrome in severe COVID-19. Science 368, 473–474. doi: 10.1126/science.abb8925

CrossRef Full Text | Google Scholar

Mouhat, B., Besutti, M., Bouiller, K., Grillet, F., Monnin, C., Ecarnot, F., et al. (2020). Elevated D-dimers and lack of anticoagulation predict PE in severe COVID-19 patients. Eur. Respir. J. 56:2001811. doi: 10.1183/13993003.01811-2020

PubMed Abstract | CrossRef Full Text | Google Scholar

Norsa, L., Bonaffini, P. A., Indriolo, A., Valle, C., Sonzogni, A., and Sironi, S. (2020). Poor outcome of intestinal ischemic manifestations of COVID-19. Gastroenterology 159, 1595.e1–1597.e1. doi: 10.1053/j.gastro.2020.06.041

PubMed Abstract | CrossRef Full Text | Google Scholar

Perepu, U. S., Chambers, I., Wahab, A., Ten Eyck, P., Wu, C., Dayal, S., et al. (2021). Standard prophylactic versus intermediate dose enoxaparin in adults with severe COVID-19: a multi-center, open-label, randomized controlled trial. J. Thromb. Haemost. 19, 2225–2234. doi: 10.1111/jth.15450

PubMed Abstract | CrossRef Full Text | Google Scholar

Pereyra, D., Heber, S., Schrottmaier, W. C., Santol, J., Pirabe, A., Schmuckenschlager, A., et al. (2021). Low molecular weight heparin use in COVID-19 is associated with curtailed viral persistence: a retrospective multicenter observational study. Cardiovasc. Res. 117, 2807–2820. doi: 10.1093/cvr/cvab308

PubMed Abstract | CrossRef Full Text | Google Scholar

Polak, S. B., Van Gool, I. C., Cohen, D., von der Thüsen, J. H., and van Paassen, J. (2020). A systematic review of pathological findings in COVID-19: a pathophysiological timeline and possible mechanisms of disease progression. Mod. Pathol. 33, 2128–2138. doi: 10.1038/s41379-020-0603-3

CrossRef Full Text | Google Scholar

Poor, H. D. (2021). Pulmonary thrombosis and thromboembolism in COVID-19. Chest 160, 1471–1480. doi: 10.1016/j.chest.2021.06.016

CrossRef Full Text | Google Scholar

Puelles, V. G., Lütgehetmann, M., Lindenmeyer, M. T., Sperhake, J. P., Wong, M. N., Allweiss, L., et al. (2020). Multiorgan and renal tropism of SARS-CoV-2. N. Engl. J. Med. 383, 590–592. doi: 10.1056/NEJMc2011400

PubMed Abstract | CrossRef Full Text | Google Scholar

Ramacciotti, E., Barile Agati, L., Calderaro, D., Aguiar, V. C. R., Spyropoulos, A. C., de Oliveira, C. C. C., et al. (2022). Rivaroxaban versus no anticoagulation for post-discharge thromboprophylaxis after hospitalisation for COVID-19 (MICHELLE): an open-label, multicentre, randomised, controlled trial. Lancet 399, 50–59. doi: 10.1016/S0140-6736(21)02392-8

PubMed Abstract | CrossRef Full Text | Google Scholar

RECOVERY Collaborative Group (2022). Aspirin in patients admitted to hospital with COVID-19 (RECOVERY): a randomised, controlled, open-label, platform trial. Lancet 399, 143–151. doi: 10.1016/S0140-6736(21)01825-0

CrossRef Full Text | Google Scholar

RECOVERY Collaborative Group Horby, P., Lim, W. S., Emberson, J. R., Mafham, M., Bell, J. L., et al. (2020). Dexamethasone in hospitalized patients with Covid-19. N. Engl. J. Med. 384, 693–704. doi: 10.1056/NEJMoa2021436

PubMed Abstract | CrossRef Full Text | Google Scholar

REMAP-CAP Investigators ACTIV-4a Investigators ATTACC Investigators Goligher, E. C., Bradbury, C. A., McVerry, B. J., et al. (2021a). Therapeutic anticoagulation with heparin in critically ill patients with Covid-19. N. Engl. J. Med. 385, 777–789. doi: 10.1056/NEJMoa2103417

PubMed Abstract | CrossRef Full Text | Google Scholar

REMAP-CAP Investigators ACTIV-4a Investigators ATTACC Investigators Lawler, P. R., Goligher, E. C., Berger, J. S., et al. (2021b). Therapeutic anticoagulation with heparin in noncritically ill patients with Covid-19. N. Engl. J. Med. 385, 790–802. doi: 10.1056/NEJMoa2105911

PubMed Abstract | CrossRef Full Text | Google Scholar

Rizvi, A., Patel, Z., Liu, Y., Satapathy, S. K., Sultan, K., and Trindade, A. J. (2021). Gastrointestinal sequelae 3 and 6 months after hospitalization for coronavirus disease 2019. Clin. Gastroenterol. Hepatol. 19, 2438.e1–2440.e1. doi: 10.1016/j.cgh.2021.06.046

CrossRef Full Text | Google Scholar

Santoro, F., Nuñez-Gil, I. J., Vitale, E., Viana-Llamas, M. C., Reche-Martinez, B., Romero-Pareja, R., et al. (2022). Antiplatelet therapy and outcome in COVID-19: the health outcome predictive evaluation registry. Heart 108, 130–136. doi: 10.1136/thoraxjnl-2021-217561

PubMed Abstract | CrossRef Full Text | Google Scholar

Shi, J., and Gilbert, G. E. (2003). Lactadherin inhibits enzyme complexes of blood coagulation by completing for phospholipid binding sites. Blood 101, 2628–2636. doi: 10.1182/blood-2002-07-1951

PubMed Abstract | CrossRef Full Text | Google Scholar

Sholzberg, M., Tang, G. H., Rahhal, H., AlHamzah, M., Kreuziger, L. B., Áinle, F. N., et al. (2021). Effectiveness of therapeutic heparin versus prophylactic heparin on death, mechanical ventilation, or intensive care unit admission in moderately ill patients with covid-19 admitted to hospital: RAPID randomised clinical trial. BMJ 375:n2400. doi: 10.1136/bmj.n2400

CrossRef Full Text | Google Scholar

Spyropoulos, A. C., Goldin, M., Giannis, D., Diab, W., Wang, J., Khanijo, S., et al. (2021). Efficacy and safety of therapeutic-dose heparin vs. standard prophylactic or intermediate-dose heparins for thromboprophylaxis in high-risk hospitalized patients with COVID-19: the HEP-COVID randomized clinical trial. JAMA Intern. Med. 181, 1612–1620. doi: 10.1001/jamainternmed.2021.6203

PubMed Abstract | CrossRef Full Text | Google Scholar

Stefan, N., Birkenfeld, A. L., and Schulze, M. B. (2021). Global pandemics interconnected – obesity, impaired metabolic health and COVID-19. Nat. Rev. Endocrinol. 17, 135–149. doi: 10.1038/s41574-020-00462-1

CrossRef Full Text | Google Scholar

Stefely, J. A., Christensen, B. B., Gogakos, T., Cone Sullivan, J. K., Montgomery, G. G., Barranco, J. P., et al. (2020). Marked factor V activity elevation in severe COVID-19 is associated with venous thromboembolism. Am. J. Hematol. 95, 1522–1530. doi: 10.1002/ajh.25979

PubMed Abstract | CrossRef Full Text | Google Scholar

Suh, Y. J., Hong, H., Ohana, M., Bompard, F., Revel, M. P., Valle, C., et al. (2021). Pulmonary embolism and deep vein thrombosis in COVID-19: a systematic review and meta-analysis. Radiology 298, E70–E80. doi: 10.1148/radiol.2020203557

CrossRef Full Text | Google Scholar

Sultan, S., Altayar, O., Siddique, S. M., Davitkov, P., Feuerstein, J. D., Lim, J. K., et al. (2020). AGA institute rapid review of the gastrointestinal and liver manifestations of COVID-19, meta-analysis of international data, and recommendations for the consultative management of patients with COVID-19. Gastroenterology 159, 320.e27–334.e27. doi: 10.1053/j.gastro.2020.05.001

PubMed Abstract | CrossRef Full Text | Google Scholar

Susen, S., Tacquard, C. A., Godon, A., Mansour, A., Garrigue, D., Nguyen, P., et al. (2020). Prevention of thrombotic risk in hospitalized patients with COVID-19 and hemostasis monitoring. Crit. Care 24:364. doi: 10.1186/s13054-020-03000-7

CrossRef Full Text | Google Scholar

Tan, B. K., Mainbourg, S., Friggeri, A., Bertoletti, L., Douplat, M., Dargaud, Y., et al. (2021). Arterial and venous thromboembolism in COVID-19: a study-level meta-analysis. Thorax 76, 970–979. doi: 10.1136/thoraxjnl-2020-215383

PubMed Abstract | CrossRef Full Text | Google Scholar

Taus, F., Salvagno, G., Canè, S., Fava, C., Mazzaferri, F., Carrara, E., et al. (2020). Platelets promote thromboinflammation in SARS-CoV-2 pneumonia. Arterioscler. Thromb. Vasc. Biol. 40, 2975–2989. doi: 10.1161/ATVBAHA.120.315175

PubMed Abstract | CrossRef Full Text | Google Scholar

Ten Cate, H. (2021). Surviving Covid-19 with heparin? N. Engl. J. Med. 385, 845–846. doi: 10.1056/NEJMe2111151

PubMed Abstract | CrossRef Full Text | Google Scholar

Tenforde, M. W., Self, W. H., Adams, K., Gaglani, M., Ginde, A. A., McNeal, T., et al. (2021). Association between mRNA vaccination and COVID-19 hospitalization and disease severity. JAMA 326, 2043–2054. doi: 10.1001/jama.2021.19499

CrossRef Full Text | Google Scholar

Thompson, M. G., Burgess, J. L., Naleway, A. L., Tyner, H., Yoon, S. K., Meece, J., et al. (2021). Prevention and attenuation of Covid-19 with the BNT162b2 and mRNA-1273 vaccines. N. Engl. J. Med. 385, 320–329. doi: 10.1056/NEJMoa2107058

PubMed Abstract | CrossRef Full Text | Google Scholar

Tong, M., Jiang, Y., Xia, D., Xiong, Y., Zheng, Q., Chen, F., et al. (2020). Elevated expression of serum endothelial cell adhesion molecules in COVID-19 patients. J. Infect. Dis. 222, 894–898. doi: 10.1093/infdis/jiaa349

CrossRef Full Text | Google Scholar

Varga, Z., Flammer, A. J., Steiger, P., Haberecker, M., Andermatt, R., Zinkernagel, A. S., et al. (2020). Endothelial cell infection and endotheliitis in COVID-19. Lancet 395, 1417–1418. doi: 10.1016/S0140-6736(20)30937-5

PubMed Abstract | CrossRef Full Text | Google Scholar

Versteeg, H. H., Heemskerk, J. W., Levi, M., and Reitsma, P. H. (2013). New fundamentals in hemostasis. Physiol. Rev. 93, 327–358. doi: 10.1152/physrev.00016.2011

PubMed Abstract | CrossRef Full Text | Google Scholar

von Meijenfeldt, F. A., Havervall, S., Adelmeijer, J., Lundström, A., Magnusson, M., Mackman, N., et al. (2021). Elevated factor V activity and antigen levels in patients with Covid-19 are related to disease severity and 30-day mortality. Am. J. Hematol. 96, E98–E100. doi: 10.1002/ajh.26085

PubMed Abstract | CrossRef Full Text | Google Scholar

Wang, P., Nair, M. S., Liu, L., Iketani, S., Luo, Y., Guo, Y., et al. (2021). Antibody resistance of SARS-CoV-2 variants B.1.351 and B.1.1.7. Nature 593, 130–135. doi: 10.1038/s41586-021-03398-2

CrossRef Full Text | Google Scholar

Wang, W., Xu, Y., Gao, R., Han, K., Wu, G., and Tan, W. (2020). Detection of SARS-CoV-2 in different types of clinical specimens. JAMA 323, 1843–1844. doi: 10.1001/jama.2020.3786

PubMed Abstract | CrossRef Full Text | Google Scholar

Wölfel, R., Corman, V. M., Guggemos, W., Seilmaier, M., Zange, S., Müller, M. A., et al. (2020). Virological assessment of hospitalized patients with COVID-2019. Nature 581, 465–469. doi: 10.1038/s41586-020-2196-x

CrossRef Full Text | Google Scholar

Xiao, F., Sun, J., Xu, Y., Li, F., Huang, X., Li, H., et al. (2020a). Infectious SARS-CoV-2 in feces of patient with severe COVID-19. Emerg. Infect. Dis. 26, 1920–1922. doi: 10.3201/eid2608.200681

PubMed Abstract | CrossRef Full Text | Google Scholar

Xiao, F., Tang, M., Zheng, X., Liu, Y., Li, X., and Shan, H. (2020b). Evidence for gastrointestinal infection of SARS-CoV-2. Gastroenterology 158, 1831.e3–1833.e3. doi: 10.1053/j.gastro.2020.02.055

PubMed Abstract | CrossRef Full Text | Google Scholar

Xie, Y., Xu, E., Bowe, B., and Al-Aly, Z. (2022). Long-term cardiovascular outcomes of COVID-19. Nat. Med. doi: 10.1038/s41591-022-01689-3 [Epub ahead of print].

CrossRef Full Text | Google Scholar

Zaid, Y., Puhm, F., Allaeys, I., Naya, A., Oudghiri, M., Khalki, L., et al. (2020). Platelets can associate with SARS-CoV-2 RNA and are hyperactivated in COVID-19. Circ. Res. 127, 1404–1418. doi: 10.1161/CIRCRESAHA.120.317703

CrossRef Full Text | Google Scholar

Zamboni, P., Bortolotti, D., Occhionorelli, S., Traina, L., Neri, L. M., Rizzo, R., et al. (2021). Bowel ischemia as onset of COVID-19 in otherwise asymptomatic patients with persistently negative swab. J. Intern. Med. 291, 224–231. doi: 10.1111/joim.13385

CrossRef Full Text | Google Scholar

Zang, R., Gomez Castro, M. F., McCune, B. T., Zeng, Q., Rothlauf, P. W., Sonnek, N. M., et al. (2020). TMPRSS2 and TMPRSS4 promote SARS-CoV-2 infection of human small intestinal enterocytes. Sci. Immunol. 5:eabc3582. doi: 10.1126/sciimmunol.abc3582

CrossRef Full Text | Google Scholar

Zhang, Y., Chen, C., Zhu, S., Shu, C., Wang, D., Song, J., et al. (2020). Isolation of 2019-nCoV from a stool specimen of a laboratory- confirmed case of the coronavirus disease 2019 (COVID-19). China CDC Wkly 2, 123–124. doi: 10.46234/ccdcw2020.033

PubMed Abstract | CrossRef Full Text | Google Scholar

Zhang, P., He, Z., Yu, G., Peng, D., Feng, Y., Ling, J., et al. (2021). The modified NUTRIC score can be used for nutritional risk assessment as well as prognosis prediction in critically ill COVID-19 patients. Clin. Nutr. 40, 534–541. doi: 10.1016/j.clnu.2020.05.051

PubMed Abstract | CrossRef Full Text | Google Scholar

Zhang, H., Shao, B., Dang, Q., Chen, Z., Zhou, Q., Luo, H., et al. (2021). Pathogenesis and mechanism of gastrointestinal infection With COVID-19. Front. Immunol. 12:674074. doi: 10.3389/fimmu.2021.674074

CrossRef Full Text | Google Scholar

Zhao, F., Yang, Y., Wang, Z., Li, L., Liu, L., and Liu, Y. (2020). The time sequences of respiratory and rectal viral shedding in patients with coronavirus disease 2019. Gastroenterology 159, 1158.e2–1160.e2. doi: 10.1053/j.gastro.2020.05.035

CrossRef Full Text | Google Scholar

Zhong, P., Xu, J., Yang, D., Shen, Y., Wang, L., Feng, Y., et al. (2020). COVID-19-associated gastrointestinal and liver injury: clinical features and potential mechanisms. Signal Transduct. Target. Ther. 5:256. doi: 10.1038/s41392-020-00373-7

PubMed Abstract | CrossRef Full Text | Google Scholar

Zhou, J., Li, C., Liu, X., Chiu, M. C., Zhao, X., Wang, D., et al. (2020). Infection of bat and human intestinal organoids by SARS-CoV-2. Nat. Med. 26, 1077–1083. doi: 10.1038/s41591-020-0912-6

Review of Mesenteric Ischemia in COVID-19 Patients

Authors: Amit GuptaOshin SharmaKandhala SrikanthRahul MishraAmoli Tandon & Deepak Rajput  Indian Journal of Surgery (2022) Published: 

Abstract

The new coronavirus (COVID-19) infection, first detected in Wuhan, China in 2019 has become a pandemic that has spread to nearly every country in the world. Through October 11, 2021, more than 23 billion confirmed cases and 4.8 million fatalities were reported globally. The bulk of individuals afflicted in India during the first wave were elderly persons. The second wave, however, resulted in more severe diseases and mortality in even younger age groups due to mutations in the wild virus. Symptoms may range from being asymptomatic to fatal acute respiratory distress syndrome (ARDS). In addition to respiratory symptoms, patients may present with gastrointestinal symptoms such as stomach pain, vomiting, loose stools, or mesenteric vein thrombosis. The frequency of patients presenting with thromboembolic symptoms has recently increased. According to certain studies, the prevalence of venous thromboembolism among hospitalized patients ranges from 9 to 25%. It was also shown that the incidence is significantly greater among critically sick patients, with a prevalence of 21–31%. Although the exact origin of thromboembolism is unknown, it is considered to be produced by several altered pathways that manifest as pulmonary embolism, myocardial infarction, stroke, limb gangrene, and acute mesenteric ischemia. Acute mesenteric ischemia (AMI) is becoming an increasingly prevalent cause of acute surgical abdomen in both intensive care unit (ICU) and emergency room (ER) patients. Mesenteric ischemia should be evaluated in situations with unexplained stomach discomfort. In suspected situations, appropriate imaging techniques and early intervention, either non-surgical or surgical, are necessary to avert mortality. The purpose of this article is to look at the data on acute mesenteric ischemia in people infected with COVID-19.

Introduction

Aside from the respiratory system, the gastrointestinal system is the most common site of SARS-COV-2 infection. This might be because enterocyte and vascular endothelial membranes have large amounts of angiotensin-converting enzyme receptor 2, a membrane integral protein. As a result, the COVID virus induces direct enterocyte invasion as well as indirect endothelial injury-induced thrombosis/intestinal ischemia in the bowel [1]. ICU patients are more prone than non-ICU patients to suffer acute mesenteric ischemia. This might be because, in addition to the direct viral activity on vascular endothelium, ICU patients have extra persistent pro-inflammatory effects. Cases have been observed even among individuals who have recovered from infection [2]. A rising number of cases of acute mesenteric ischemia in COVID-19 patients have been reported in the literature since the outbreak of this pandemic (list of reported cases are summarized in the Table 1). AMI risk was shown to be increased with age, male sex, and comorbidities such as hypertension, obesity, and diabetes mellitus. Because of delayed clinical manifestation, AMI-related mortality is quite significant, with 60–80% [3].Table 1 Summary of the cases reported on mesenteric ischemia in COVID-19 patientsFull size table

Case summary

A 55 years old man with no known comorbidity presented to the emergency department of our institute with severe pain abdomen and multiple episodes of vomiting. He reported the recent recovery from the non-complicated COVID-related illness. He did not report any intake of anticoagulants. On clinical examination, abdomen was unremarkable. X-ray chest, x-ray erect abdomen, and ultrasound abdomen were unremarkable. Mesenteric ischemia was suspected and the patient was subjected to CT angiography abdomen, which revealed thrombus at the origin of the superior mesenteric artery and impending gangrene of the small bowel (Fig. 1). Emergency laparotomy was done and intraoperatively found the gangrenous bowel involving the distal jejunum and almost the entire ileum sparing the terminal ileum (Fig. 2). Resection of the gangrenous small bowel and end jejunostomy was done. Later, he was given ICU care, but unfortunately, the patient succumbed to multi-organ dysfunction syndrome.

figure 1
Fig. 1
figure 2
Fig. 2

Pathophysiology

Although the specific etiology of hypercoagulable state and subsequent mesenteric ischemia in COVID-19 patients is unknown, these thromboembolic events can be related to alterations in all three Virchow triad characteristics (vascular endothelial injury, hypercoagulability, and stasis). A variety of variables complicate the etiology of thrombus development, one of which is vascular endothelial injury. Capillary permeability, hemostasis, and fibrinolysis are all maintained by the vascular endothelium (Fig. 3). Direct invasion causes endothelial cells to be damaged and lysed, resulting in an imbalance between pro and anticoagulant states [4]. Furthermore, vascular endothelial cells displayed morphological changes such as cellular expansion, retraction, and intercellular connection breakage [5]. The elevated levels of pro-inflammatory markers, von Willebrand factor, tissue factor, fibrinogen, and circulating microvesicles in the COVID-19 patients explain their hypercoagulability [6]. Antiphospholipid antibodies are elevated in some situations [7]. Patients who are critically ill, on limited oxygen support, and mechanical breathing are less mobilized, which increases the risk of deep venous thrombosis [3].

figure 3
Fig. 3

These mesenteric vascular thromboses cause acute hypoxia in the intestinal wall, which stimulates the renin-angiotensin system, causing mesenteric vasospasm and an elevated risk of hypoxic injury. SARS-COV binds to ACE 2 receptors in intestinal cells, causing cell lysis [8]. As a result, both hypoxia and direct invasion can trigger intestinal cell death. The loss of this epithelial barrier function in the gut promotes increased contact with enteric bacteria/endotoxins and viral particle penetration into the circulation [5]. The hypoxia continues, resulting in transmural infarction, perforation, and peritonitis. In one example of mesenteric ischemia induced by invasive mucormycosis, the presence of fungal components in the mesenteric microcirculation was documented [2]. See the flow chart summarizing the pathophysiology of mesenteric ischemia in covid-19 infection.

Clinical Presentation

Patients with mesenteric ischemia may exhibit a range of symptoms, from nonspecific complaints to peritonitis-like symptoms. Most of the patients developed symptoms a few days after being discharged successfully with proper symptomatic inpatient care. Although the respiratory symptoms predominate mesenteric ischemia presents with nonspecific abdominal symptoms such as loose stools, abdominal pain, nausea, vomiting, abdominal distension, and bleeding per rectum may occur in addition to the usual clinical presentation with respiratory features [6]. When opposed to arterial thrombosis, venous thrombosis has a delayed onset of symptoms. At first, sudden onset pain in the abdomen may be the sole symptom, and it may develop after 5–14 days. Abdominal clinical examination is nonyielding in the majority of cases. Abdominal signs would not develop unless the bowel gangrene or bowel perforation with peritonitis occurs [9].

Investigations

Blood investigations

Despite extensive study on the subject of acute mesenteric ischemia, the associated biomarkers were shown to be neither sensitive nor selective [10]. Elevated lactic acid levels and fibrin degradation products like D-dimer have low specificity and remain elevated in severe COVID-19 without AMI. However, biomarkers associated with hypercoagulable conditions aid in the initiation of preventive treatment and, to a lesser extent, in the management of COVID-related thrombotic events. Increased biomarkers of inflammation and infection include leukopenia (due to corticosteroid usage) and other signs such as C-reactive protein, procalcitonin, and IL-6. D-dimer, ferritin, prothrombin time, and lactate dehydrogenase are additional significant markers. The severity of increased lactate dehydrogenase and ferritin levels is associated with high mortality[8].

Radiological imaging

In the emergency room, an X-ray of the abdomen and an ultrasound are helpful for early examinations. X-ray of the erect abdomen helps in initial assessment in cases presented with features of obstruction or perforation. Ultrasound in the early phase may show SMA occlusion and bowel spasm or ultrasound findings in the early stages of acute mesenteric ischemia may appear normal [11]. In the intermediate phase, USG is not useful because of the presence of a large amount of gas-filled intestinal loops. In the late phase, USG may reveal fluid-filled lumen, bowel wall thinning, evidence of extra-luminal fluid, decreased or absent peristalsis. Therefore, USG may be helpful in the diagnosis of advanced bowel obstruction, gangrene, and perforation with peritoneal collection [12]. Ultrasonography revealed some other important features with distended and sludge-filled gall bladder with bile stasis. Portal venous gas also can be detected on ultrasonography which can be better characterized with the help of computed tomography [13].

Computed tomography

The gold standard investigation is CT angiography. CT observations commonly encountered in acute mesenteric ischemia secondary to COVID-19 includes thrombus in the aorta/SMA/portal circulation, augmentation of the bowel wall, thickness of the bowel wall with distention(> 3 cm), edema, and stranding of the mesentery, pneumatosis intestinalis or portal venous gas suggesting bowel wall ischemia, and non-enhancing thick bowel wall seen in bowel infarction, bowel perforation secondary to bowel infarction may present discontinuity of bowel wall with localized air collection. One should remember that pneumatosis intestinalis may also occur due to mechanical ventilation. Pneumoperitoneum occurs when there is severe intestinal necrosis and perforation. There were additional reports of nonspecific features such as a dilated gut with a fluid-filled lumen, distended gallbladder with bile stasis, features of solid organ ischemia, and pancreatitis [14]. MRI, despite its accessibility, has drawbacks such as a longer acquisition time and lower resolution than CT angiography [12].

Management

A summary of cases of acute mesenteric ischemia has been tabulated (Table 1). Management of acute mesenteric ischemia in COVID-19 includes the following:

  • Supportive measures: Crystalloid rehydration and empirical antibacterial treatment should begin before angiography or any surgical resection. Comorbidity management, hemodynamic support in unstable patients, and electrolyte balance correction are all critical components of patient care [10].
  • Anticoagulation: There is insufficient data in 19 patients to warrant thromboprophylaxis. According to the Tang et al. study, low-dose heparin prophylaxis decreased thrombotic events and mortality in those with D-dimer levels over 3 mg/ml. Despite the increased risk of bleeding, mesenteric ischemia should be treated with intraoperative and postoperative anticoagulation [15].
  • Revascularisation: Revascularization with catheter-directed thrombolysis and thrombectomy by percutaneous/surgical intervention can be explored in instances where there is no indication of significant intestinal ischemia. Catheter-directed thrombolysis with unfractionated heparin and recombinant tissue plasminogen activators can accomplish this. Because of the increased risk of re-thrombosis, vascular clearance is not indicated in instances of superior mesenteric vein thrombus [15].
  • Resection of the gangrenous bowel: Depending on clinical suspicion, a CT angiography examination of mesenteric vasculature and bowel health can be performed, and an emergency exploration call should be placed. Intraoperatively, if the patient is normotensive, has no sepsis or peritonitis, and the remaining bowel viability is unquestionable, the gangrenous bowel is to be removed, and the remaining bowel can be considered for re-anastomosis. In unfavorable circumstances, a stoma should be created following gangrenous bowel resection [11]. The margin dissection in venous thrombosis should be broader than in arterial thrombosis. To assure the bowel’s survivability, abdominal closure should be temporary, and a relook laparotomy should be done 48 h later. Histopathological examination of the resected intestine may indicate patchy or widespread necrotic changes from mucosa to transmural thickness. In the submucosal vasculature, fibrin-containing microthrombi with perivascular neutrophilic infiltration is observed.
  • Management of short bowel syndrome: The therapy varies depending on the length of colon left after excision of infarcted bowel caused by mesenteric ischemia.
  • Medical- In severe diarrhea, fluid and electrolyte loss must be replaced. TPN for feeding and histamine-2 receptor antagonists or PPIs for stomach acid secretion reduction. Loperamide and diphenoxylate are anti-motility medicines that delay small intestine transit whereas Octreotide reduces the volume of gastrointestinal secretions.
  • Non-transplant surgical therapy- Done to improve the absorption capacity of the remaining intestine by restoring intestinal continuity. Increased nutrient and fluid absorption is the goal. Segmental reversal of the small bowel, fabrication of small intestinal valves, and electrical pacing of the small bowel are all procedures used to delay intestinal transit. Longitudinal intestinal lengthening and tailoring technique (LILT) and serial transverse arthroplasty process are two intestinal lengthening procedures (STEP).
  • Intestinal transplantation- Life-threatening problems such as liver failure, thrombosis of major central veins, frequent episodes of severe dehydration, and catheter-related sepsis are reasons for intestinal transplantation [16].

Prognosis

Acute mesenteric ischemia has a poor prognosis, and life is reliant on prompt diagnosis and treatment. If detected within 24 h, the likelihood of survival is 50%, but it declines to 30% beyond that [17].In operated cases, COVID infection acts as an independent risk factor and is responsible for higher mortality [18].

Conclusion

SARS-COV-2 infection even though initially thought to be respiratory infection; later cases detected presenting with multisystem involvement. The presentation may vary from asymptomatic or mildly symptomatic to severe respiratory distress syndrome or thromboembolic phenomenon requiring ICU care. The exact mechanism of thromboembolism is not established. However, the increasing number of acute mesenteric ischemia is quite alarming. The treating physician should be overcautious in patients presenting with abdominal symptoms either currently affected or recovered from COVID-related illness. In high-risk patients, early start of prophylactic anticoagulation may be beneficial. Earlier intervention is known acute mesenteric ischemia cases with operative or minimally invasive procedures may give higher survival benefits. It mandates more research to determine the causes of thromboembolism, as well as preventive and therapeutic anticoagulation in these individuals.

References

  1. Jin B, Singh R, Ha SE, Zogg H, Park PJ, Ro S (2021) Pathophysiological mechanisms underlying gastrointestinal symptoms in patients with COVID-19. World J Gastroenterol. Baishideng Publishing Group Co 27:2341–52CAS Article Google Scholar 
  2. Jain M, Tyagi R, Tyagi R, Jain G (2021) Post-COVID-19 gastrointestinal invasive mucormycosis. Indian J Surg 22:1–3
  3. Kerawala AA, Das B, Solangi A (2021) Mesenteric ischemia in COVID-19 patients: a review of current literature. World J Clin Cases 9(18):4700–4708Article Google Scholar 
  4. Kichloo A, Dettloff K, Aljadah M, Albosta M, Jamal S, Singh J et al (2020) COVID-19 and hypercoagulability: a review. Clin Appl Thromb 26
  5. Parry AH, Wani AH, Yaseen M (2020) Acute mesenteric ischemia in severe Coronavirus-19 (COVID-19): possible mechanisms and diagnostic pathway. Acad Radiol 27(8):1190Article Google Scholar 
  6. Cheung S, Quiwa JC, Pillai A, Onwu C, Tharayil ZJ, Gupta R (2020) Superior mesenteric artery thrombosis and acute intestinal ischemia as a consequence of COVID-19 infection. Am J Case Rep 21:1–3Google Scholar 
  7. Zhang Y, Xiao M, Zhang S, Xia P, Cao W, Jiang W et al (2020) Coagulopathy and antiphospholipid antibodies in patients with Covid-19. N Engl J Med. 382(17):e38Article Google Scholar 
  8. Al Mahruqi G, Stephen E, Abdelhedy I, Al WK (2021) Our early experience with mesenteric ischemia in COVID-19 positive patients. Ann Vasc Surg 73:129–132Article Google Scholar 
  9. Karna ST, Panda R, Maurya AP, Kumari S (2020) Superior mesenteric artery thrombosis in COVID-19 Pneumonia: an underestimated diagnosis—first case report in Asia. Indian J Surg 82(6):1235–1237Article Google Scholar 
  10. Singh B, Kaur P (2021) COVID-19 and acute mesenteric ischemia: a review of literature. Hematol Transfus Cell Ther 43(1):112–116Article Google Scholar 
  11. Janež J, Klen J (2021) Multidisciplinary diagnostic and therapeutic approach to acute mesenteric ischaemia: a case report with literature review. SAGE Open Med Case Rep 9:2050313X2110048Article Google Scholar 
  12. Mc W (2010) Acute mesenteric ischemia: diagnostic approach and surgical treatment. Semin Vasc Surg 23(1):9–20Article Google Scholar 
  13. Bhayana R, Som A, Li MD, Carey DE, Anderson MA, Blake MA et al (2020) Abdominal imaging findings in COVID-19: Preliminary observations. Radiology 297(1):E207–E215
  14. Keshavarz P, Rafiee F, Kavandi H, Goudarzi S, Heidari F, Gholamrezanezhad A (2021) Ischemic gastrointestinal complications of COVID-19: a systematic review on imaging presentation. Clin Imaging 73:86–95Article Google Scholar 
  15. Bergqvist D, Svensson PJ (2010) Treatment of mesenteric vein thrombosis. Semin Vasc Surg 23(1):65–68Article Google Scholar 
  16. Seetharam P, Rodrigues G (2011) Short bowel syndrome: a review of management options. Saudi J Gastroenterol 17(4):229–235Article Google Scholar 
  17. Krothapalli N, Jacob J (2021) A rare case of acute mesenteric ischemia in the setting of COVID-19 infection. Cureus 13(3):0–4Google Scholar 
  18. Haffner MR, Le HV, Saiz AM, Han G, Fine J, Wolinsky P et al (2021) Postoperative In-hospital morbidity and mortality of patients with COVID-19 infection compared with patients without COVID-19 infection. JAMA Netw Open 4(4):10–13Article Google Scholar 
  19. Ucpinar BA, Sahin C (2020) Superior mesenteric artery thrombosis in a patient with COVID-19: a unique presentation. J Coll Physicians Surg Pak 30(10):S112–S114Google Scholar 
  20. Khesrani LS, Chana k, Sadar FZ, Dahdouh A, Ladjadj Y, Bouguermouh D (2020) Intestinal ischemia secondary to Covid-19. J Pediatr Surg Case Rep 61:101604Article Google Scholar 
  21. Norsa L, Valle C, Morotti D, Bonaffini PA, Indriolo A, Sonzogni A (2020) Intestinal ischemia in the COVID-19 era. Dig Liver Dis 52(10):1090–1091CAS Article Google Scholar 
  22. Rodriguez-Nakamura RM, Gonzalez-Calatayud M, Martinez Martinez AR (2020) Acute mesenteric thrombosis in two patients with COVID-19. Two cases report and literature review. Int J Surg Case Rep 76:409–14Article Google Scholar 
  23. VartanogluAktokmakyan T, Tokocin M, Meric S, Celebi F (2021) Is mesenteric ischemia in COVID-19 patients a surprise? Surg Innov 28(2):236–238Article Google Scholar 
  24. Levolger S, Bokkers RPH, Wille J, Kropman RHJ, de Vries JPPM (2020) Arterial thrombotic complications in COVID-19 patients. J Vasc Surg Cases Innov Tech 6(3):454–459Article Google Scholar 
  25. Thuluva SK, Zhu H, Tan MML, Gupta S, Yeong KY, Wah STC et al (2020) A 29-year-old male construction worker from india who presented with left-sided abdominal pain due to isolated superior mesenteric vein thrombosis associated with SARS-CoV-2 infection. Am J Case Rep 21:1–5Article Google Scholar 
  26. Lari E, Lari A, AlQinai S, Abdulrasoul M, AlSafran S, Ameer A et al (2020) Severe ischemic complications in Covid-19—a case series. Int J Surg Case Rep 75(June):131–135Article Google Scholar 
  27. Singh B, Mechineni A, Kaur P, Ajdir N, Maroules M, Shamoon F et al (2020) Acute intestinal ischemia in a patient with COVID-19 infection. Korean J Gastroenterol 76(3):164–166Article Google Scholar 
  28. De Roquetaillade C, Chousterman BG, Tomasoni D, Zeitouni M, Houdart E (2020) Since January 2020 Elsevier has created a COVID-19 resource centre with free information in English and Mandarin on the novel coronavirus COVID- 19. The COVID-19 resource centre is hosted on Elsevier Connect , the company ’ s public news and information. (January)
  29. Sehhat S, Talebzadeh H, Hakamifard A, Melali H, Shabib S, Rahmati A et al (2020) Acute mesenteric ischemia in a patient with COVID-19: a case report. Arch Iran Med 23(9):639–643Article Google Scholar 
  30. Beccara LA, Pacioni C, Ponton S, Francavilla S, Cuzzoli A (2020) Arterial mesenteric thrombosis as a complication of SARS-CoV-2 infection. Eur J Case Rep Intern Med 7(5).
  31. Ignat M, Philouze G, Aussenac-belle L (2020) Since January 2020 Elsevier has created a COVID-19 resource centre with free information in English and Mandarin on the novel coronavirus COVID- 19 . The COVID-19 resource centre is hosted on Elsevier Connect , the company ’ s public news and information. (Jan)
  32. Farina D, Rondi P, Botturi E, Renzulli M, Borghesi A, Guelfi D et al (2021) Gastrointestinal: bowel ischemia in a suspected coronavirus disease (COVID-19) patient. J Gastroenterol Hepatol 36(1):41CAS Article Google Scholar 
  33. Azouz E, Yang S, Monnier-Cholley L, Arrivé L (2020) Systemic arterial thrombosis and acute mesenteric ischemia in a patient with COVID-19. Intensive Care Med 46(7):1464–1465CAS Article Google Scholar 
  34. Vulliamy P, Jacob S, Davenport RA (2020) Acute aorto-iliac and mesenteric arterial thromboses as presenting features of COVID-19. Br J Haematol 189(6):1053–1054CAS Article Google Scholar 
  35. Bianco F, Ranieri AJ, Paterniti G, Pata F, Gallo G (2020) Acute intestinal ischemia in a patient with COVID-19. Tech Coloproctol 24(11):1217–1218CAS Article Google Scholar 
  36. Filho A do C, Cunha B da S (2020) Case report – inferior mesenteric vein thrombosis and COVID-19. 2020060282
  37. Mitchell JM, Rakheja D, Gopal P (2021) SARS-CoV-2-related hypercoagulable state leading to ischemic enteritis secondary to superior mesenteric artery thrombosis. Clin Gastroenterol Hepatol 19(11):e111CAS Article Google Scholar 
  38. English W, Banerjee S (2020) Coagulopathy and mesenteric ischaemia in severe SARS-CoV-2 infection. ANZ J Surg 90(9):1826Article Google Scholar 
  39. de Barry O, Mekki A, Diffre C, Seror M, El Hajjam M, Carlier RY (2020) Arterial and venous abdominal thrombosis in a 79-year-old woman with COVID-19 pneumonia. Radiol Case Rep 15(7):1054–1057Article Google Scholar 
  40. Kraft M, Pellino G, Jofra M, Sorribas M, Solís-Peña A, Biondo S, Espín-Basany E (2021) Incidence, features, outcome and impact on health system of de-novo abdominal surgical diseases in patients admitted with COVID-19. Surg J R Coll Surg Edinb Irel 19:e53–e58Google Scholar 
  41. Besutti G, Bonacini R, Iotti V, Marini G, Riva N, Dolci G et al (2020) Abdominal visceral infarction in 3 patients with COVID-19. Emerg Infect Dis 26(8):1926–1928CAS Article Google Scholar 
  42. Kielty J, Duggan WP, O’Dwyer M (2020) Extensive pneumatosis intestinalis and portal venous gas mimicking mesenteric ischaemia in a patient with SARS-CoV-2. Ann R Coll Surg Engl 102(6):E145–E147CAS Article Google Scholar 
  43. Pang JHQ, Tang JH, Eugene-Fan B (2021) A peculiar case of small bowel stricture in a coronavirus disease 2019 patient with congenital adhesion band and superior mesenteric vein thrombosis. Ann Vasc Surg 70:286–289Article Google Scholar 
  44. Osilli D, Pavlovica J, Mane R, Ibrahim M, Bouhelal A, Jacob S (2020) Case reports: mild COVID-19 infection and acute arterial thrombosis. J Surg Case Rep (9):1–3