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Ramatroban, a Thromboxane A2/TPr and PGD2/DPr2 receptor antagonist for Acute and Long haul COVID-19
Author: Ajay Gupta, MD
From: “Gupta, Ajay” <ajayg1@hs.uci.edu> Date: Wednesday, July 7, 2021 at 1:10 PM To: Aviva Lev-Ari <AvivaLev-Ari@alum.berkeley.edu> Cc: “Dr. Saul Yedgar” <saulye@ekmd.huji.ac.il> Subject: Ramatroban, a Thromboxane A2/TPr and PGD2/DPr2 receptor antagonist for Acute and Long haul COVID-19
While corticosteroids may have a role in about 5% of hospitalized patients who have the cytokine storm, currently there is no effective treatment for mild or moderate COVID and long haul COVID. Massive increase in respiratory and plasma thromboxane A2 (TxA2) plays a key role in thromboinflammation and microvascular thrombosis, while an increase in respiratory and plasma PGD2 potentially suppresses innate interferon response, and acquired Th1 anti-viral response, while promoting a maladaptive type 2, anti-helminthic like immune response. Ramatroban is a potent dual receptor antagonist of Thromboxane A2/TPr and PGD2/DPr2 that has been used in Japan for the treatment of allergic rhinitis for past 20 years (Baynas®, Bayer Japan). We first disclosed use of ramatroban for COVID in a provisional patent application filed on 31st March, 2020; followed by the publication Gupta et al, J Mol Genet Med, 2020
Several experts, as outlined below in yellow highlighted text, have supported the idea of using ramatroban as an anti-thrombotic and immunomodulator in COVID-19.
1. Prof. Louis Flamand, Nicolas Flamand, Eric Boilard Laval Univ. Quebec, Canada: There is a lipid-mediator storm in COVID-19 characterized by massive increases in thromboxane A2 and PGD2 in the lungs and plasma. “Blocking the deleterious effects of PGD2 and TxA2 with the dual DPr2/TPr antagonist Ramatroban might be beneficial in COVID-19Archambault et al, FASEB, June 2021, doi: https://doi.org/10.1096/fj.202100540R
2. Prof. Garret A FitzGerald, Univ. Of Pennsylvania, Member National Academy of Sciences.https://en.wikipedia.org/wiki/Garret_A._FitzGerald “In the current pandemic there may be utility in targeting eicosanoids with existing drugs. These approaches would likely be most effective early in the disease before the development of ARDS, where cytokines and chemokines dominate. Dexamethasone limits COX-2 expression and might diminish COVID-19 severity and mortality at least in part, by diminishing COX metabolites… Dexamethasone might improve severe COVID-19 by diminishing the prostaglandins / thromboxane storm in the lungs”. “Treatment with a PGD2/DPr2 inhibitor decreased viral load and improved morbidity by upregulating IFN-lambda expression. ….. Antagonism of the thromboxane receptor (TPr) prevents ARDS…. Early administration of well-tolerated TPr antagonists may limit progress to severe COVID-19 (Theken and FitzGerald, Science, 2021)
4. Prof. Simon Phipps, Univ. of Queensland, Brisbane Australia “It has been hypothesized that DP2 antagonists be repurposed as a novel immunotherapy for the treatment of COVID-19, and this may be appropriate in mild to moderate cases where Th1 immunity is impaired.” (Ullah et al, Mucosal Immunology, 2021)
5. Prof. Bruce D. Hammock, Distinguished Professor, Univ of California Davis, Member US National Academy of Sciences and National Academy of Inventors; April 25, 2021. https://www.entsoc.org/fellows/hammock “I find your idea of blocking specific thromboxane receptors in preventing or reducing some of the devastating co-morbidity of COVID-19 very compelling. … A DPr2 receptor blocker is conceptually attractive in offering the potential of effective therapy and low risk due to a high therapeutic index.” E mail dated April 25, 2021.(https://ajp.amjpathol.org/action/showPdf?pii=S0002-9440%2820%2930332-1 and http://ucanr.edu/sites/hammocklab/files/328012.pdf)
6. Ann E Eakin, PhD, Senior Scientific Officer, NIH-NIAID “very compelling data supporting potential benefits of ramatroban in both reducing viral load as well as modulating host responses” E Mail dated Nov 20, 2020
Ramatroban is expected to reduce lung fibrosis in COVID-19 and therefore diminish clinical manifestations of Long haul COVID. Pang et al, 2021 “examined the effect of Ramatroban, a clinical antagonist of both PGD2 and TXA2 receptors, on treating silicosis using a mouse model. The results showed that Ramatroban significantly alleviated silica-induced pulmonary inflammation, fibrosis, and cardiopulmonary dysfunction compared with the control group.” https://www.thno.org/v11p2381.htm
Unfortunately, the animal models of COVID-19 are harsh, lack microvascular thrombosis and immune perturbations characteristic of human disease. These models may be good for testing antivirals but not for testing immunomodulators or anti-thrombotics. There is highly positive anecdotal experience with use of ramatroban in moderately severe COVID-19 (https://www.researchsquare.com/article/rs-474882/v1
Reporter and Curator: Mr. Srinjoy Chakraborty (Junior Research Felllow) and Dr. Sudipta Saha, Ph.D.
Coronavirus disease 2019 (COVID-19), which is caused by the novel severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), has emerged as a serious global health issue with high transmission rates affecting millions of people worldwide. The SARS-CoV-2 is known to damage cells in the respiratory system, thus causing viral pneumonia. The novel SARS-CoV-2 is a close relative to the previously identified severe acute respiratory syndrome-coronavirus (SARS-CoV) and Middle East respiratory syndrome-coronavirus (MERS-CoV) which affected several people in 2002 and 2012, respectively. Ever since the outbreak of covid-19, several reports have poured in about the impact of Covid-19 on pregnancy. A few studies have highlighted the impact of the viral infection in pregnant women and how they are more susceptible to the infection because of the various physiological changes of the cardiopulmonary and immune systems during pregnancy. It is known that SARS-CoV and MERS-CoV diseases have influenced the fatality rate among pregnant women. However, there are limited studies on the impact of the novel corona virus on the course and outcome of pregnancy.
Figure: commonly observed clinical symptoms of COVID-19 in the general population: Fever and cough, along with dyspnoea, diarrhoea, and malaise are the most commonly observed symptoms in pregnant women, which is similar to that observed in the normal population.
The WHO and the Indian Council of Medical Research (ICMR) have proposed detailed guidelines for treating pregnant women; these guidelines must be strictly followed by the pregnant individual and their families. According to the guidelines issued by the ICMR, the risk of pregnant women contracting the virus to that of the general population. However, the immune system and the body’s response to a viral infection is altered during pregnancy. This may result in the manifestation of more severe symptoms. The ICMR guidelines also state that the reported cases of COVID-19 pneumonia in pregnancy are milder and with good recovery. However, by observing the trends of the other coronavirus infection (SARS, MERS), the risks to the mother appear to increase in particular during the last trimester of pregnancy. Cases of preterm birth in women with COVID-19 have been mentioned in a few case report, but it is unclear whether the preterm birth was always iatrogenic, or whether some were spontaneous. Pregnant women with heart disease are at highest risk of acquiring the infection, which is similar to that observed in the normal population. Most importantly, the ICMR guidelines highlights the impact of the coronavirus epidemic on the mental health of pregnant women. It mentions that the since the pandemic has begun, there has been an increase in the risk of perinatal anxiety and depression, as well as domestic violence. It is critically important that support for women and families is strengthened as far as possible; that women are asked about mental health at every contact.
With the available literature available on the impact of SARS and MERS on reproductive outcome, it has been mentioned that SARS infection did increase the risk of miscarriage, preterm birth and, intrauterine foetal growth restriction. However, the same has not been demonstrated in early reports from COVID-19 infection in pregnancy. According to a study that included 8200 participants conducted by the centre for disease control and prevention, pregnant women may be at a higher risk of acquiring severe infection and need for ICU admissions as compared to their non-pregnant counterparts. However, a detailed and thorough study involving a larger proportion of the population is needed today.
Reporter and Original Article Co-Author: Amandeep Kaur, B.Sc. , M.Sc.
Abstract Since its inception in late 2019, SARS-CoV-2 has evolved resulting in emergence of various variants in different countries. These variants have spread worldwide resulting in devastating second wave of COVID-19 pandemic in many countries including India since the beginning of 2021. To control this pandemic continuous mutational surveillance and genomic epidemiology of circulating strains is very important. In this study, we performed mutational analysis of the protein coding genes of SARS-CoV-2 strains (n=2000) collected during January 2021 to March 2021. Our data revealed the emergence of a new variant in West Bengal, India, which is characterized by the presence of 11 co-existing mutations including D614G, P681H and V1230L in S-glycoprotein. This new variant was identified in 70 out of 412 sequences submitted from West Bengal. Interestingly, among these 70 sequences, 16 sequences also harbored E484K in the S glycoprotein. Phylogenetic analysis revealed strains of this new variant emerged from GR clade (B.1.1) and formed a new cluster. We propose to name this variant as GRL or lineage B.1.1/S:V1230L due to the presence of V1230L in S glycoprotein along with GR clade specific mutations. Co-occurrence of P681H, previously observed in UK variant, and E484K, previously observed in South African variant and California variant, demonstrates the convergent evolution of SARS-CoV-2 mutation. V1230L, present within the transmembrane domain of S2 subunit of S glycoprotein, has not yet been reported from any country. Substitution of valine with more hydrophobic amino acid leucine at position 1230 of the transmembrane domain, having role in S protein binding to the viral envelope, could strengthen the interaction of S protein with the viral envelope and also increase the deposition of S protein to the viral envelope, and thus positively regulate virus infection. P618H and E484K mutation have already been demonstrated in favor of increased infectivity and immune invasion respectively. Therefore, the new variant having G614G, P618H, P1230L and E484K is expected to have better infectivity, transmissibility and immune invasion characteristics, which may pose additional threat along with B.1.617 in the ongoing COVID-19 pandemic in India.
Study: Emergence of a new SARS-CoV-2 variant from GR clade with a novel S glycoprotein mutation V1230L in West Bengal, India
Start Quote from European Medicines Agency document
Meeting highlights from the Pharmacovigilance Risk Assessment Committee (PRAC) 3-6 May 2021
News 07/05/2021
This month EMA’s safety committee (PRAC) reviewed a number of safety signals related to COVID-19 vaccines. The evaluation of safety signals is a routine part of pharmacovigilance and is essential to ensuring that regulatory authorities have a comprehensive knowledge of a medicine’s benefits and risks.
PRAC concludes review of signal of facial swelling with COVID-19 vaccine Comirnaty
PRAC has recommended a change to Comirnaty’s product information. After reviewing all the available evidence, including cases reported to the European database for suspected side effects (EudraVigilance) and data from the scientific literature, PRAC considered that there is at least a reasonable possibility of a causal association between the vaccine and the reported cases of facial swelling in people with a history of injections with dermal fillers (soft, gel-like substances injected under the skin). Therefore, PRAC concluded that facial swelling in people with a history of injections with dermal fillers should be included as a side effect in section 4.8 of the summary of product characteristics (SmPC) and in section 4 of the patient information leaflet (PIL) for Comirnaty. The benefit-risk balance of the vaccine remains unchanged.
PRAC concludes review of unusual blood clots with low blood platelets1 with Janssen’s COVID-19 vaccine
PRAC has now concluded its review of COVID-19 Vaccine Janssen and confirmed, as previously communicated, that the benefits of the vaccine in preventing COVID-19 outweigh the risks of side effects. In finalising the review, the Committee recommended on 20 April further refinement of the warning about thrombosis (formation of blood clots in the vessels) with thrombocytopenia (low blood platelets) syndrome, which was listed previously in the product information for COVID-19 Vaccine Janssen. The product information will now also include advice that patients who are diagnosed with thrombocytopenia within three weeks of vaccination should be actively investigated for signs of thrombosis. Similarly, patients who present with thromboembolism within three weeks of vaccination should be evaluated for thrombocytopenia. Lastly, thrombosis with thrombocytopenia syndrome will be added as an ‘important identified risk’ in the risk management plan for the vaccine. Furthermore, the marketing authorisation holder will provide a plan to further study the possible underlying mechanisms for these very rare events.
PRAC continues to closely review Comirnaty and COVID-19 Vaccine Moderna for unusual blood clots with low blood platelets2
The PRAC is closely monitoring whether mRNA vaccines might also be linked to cases of rare, unusual blood clots with low blood platelets, a side effect that has been reported in Vaxzevria and COVID-19 vaccine Janssen. Following a review of reports of suspected side effects, the PRAC considers at this stage that there is no safety signal for the mRNA vaccines. Only few cases of blood clots with low blood platelets have been reported. When seen in the context of the exposure of people to the mRNA vaccines, these numbers are extremely low, and their frequency is lower than the one occurring in people who have not been vaccinated. In addition, these cases do not seem to present the specific clinical pattern observed with Vaxzevria and COVID-19 Vaccine Janssen. Overall, the current evidence does not suggest a causal relation.
EMA will continue to monitor this issue closely and communicate further if necessary.
Topics of interests from enhanced monitoring of COVID-19 vaccines
Enhanced safety monitoring in the form of pandemic summary safety reports is one of the commitments required from the marketing authorisation holders in the context of the conditional marketing authorisation. Marketing authorisation holders are required to submit pandemic summary safety reports to EMA on a monthly basis. These reports are reviewed by the PRAC and any areaof concern further investigated, if needed.
PRAC assessing reports of Guillain-Barre syndrome with AstraZeneca’s Covid-19 vaccine
As part of the review of the regular pandemic summary safety reports for Vaxzevria, AstraZeneca’s Covid-19 vaccine, the PRAC is analysing data provided by the marketing authorisation holder on cases of Guillain-Barre syndrome (GBS) reported following vaccination. GBS is an immune system disorder that causes nerve inflammation and can result in pain, numbness, muscle weakness and difficulty walking. GBS was identified during the marketing authorisation process as a possible adverse event requiring specific safety monitoring activities. PRAC has requested the marketing authorisation holder to provide further detailed data, including an analysis of all the reported cases in the context of the next pandemic summary safety report.
PRAC will continue its review and will communicate further when new information becomes available.
PRAC assessing reports of myocarditis with Comirnaty and COVID-19 Vaccine Moderna
EMA is aware of cases of myocarditis (inflammation of the heart muscle) and pericarditis (inflammation of the membrane around the heart) mainly reported following vaccination with Comirnaty. There is no indication at the moment that these cases are due to the vaccine. However, PRAC has requested the marketing authorisation holder to provide further detailed data, including an analysis of the events according to age and gender, in the context of the next pandemic summary safety report and will consider if any other regulatory action is needed. Additionally, the PRAC has requested the marketing authorisation holder for COVID-19 Vaccine Moderna– also an mRNA vaccine – to monitor similar cases with their vaccine and to also provide a detailed analysis of the events in the context of the next pandemic summary safety report. EMA will communicate further when new information becomes available.
1Thrombosis with thrombocytopenia syndrome 2Thrombosis with thrombocytopenia syndrome
Nir Hacohen and Marcia Goldberg, Researchers at MGH and the Broad Institute identify protein “signature” of severe COVID-19
Curator and Reporter: Aviva Lev-Ari, PhD, RN
Longitudinal proteomic analysis of plasma from patients with severe COVID-19 reveal patient survival-associated signatures, tissue-specific cell death, and cell-cell interactions
16% of COVID-19 patients display an atypical low-inflammatory plasma proteome
Severe COVID-19 is associated with heterogeneous plasma proteomic responses
Death of virus-infected lung epithelial cells is a key feature of severe disease
Lung monocyte/macrophages drive T cell activation, together promoting epithelial damage
Summary
Mechanisms underlying severe COVID-19 disease remain poorly understood. We analyze several thousand plasma proteins longitudinally in 306 COVID-19 patients and 78 symptomatic controls, uncovering immune and non-immune proteins linked to COVID-19. Deconvolution of our plasma proteome data using published scRNAseq datasets reveals contributions from circulating immune and tissue cells. Sixteen percent of patients display reduced inflammation yet comparably poor outcomes. Comparison of patients who died to severely ill survivors identifies dynamic immune cell-derived and tissue-associated proteins associated with survival, including exocrine pancreatic proteases. Using derived tissue-specific and cell type-specific intracellular death signatures, cellular ACE2 expression, and our data, we infer whether organ damage resulted from direct or indirect effects of infection. We propose a model in which interactions among myeloid, epithelial, and T cells drive tissue damage. These datasets provide important insights and a rich resource for analysis of mechanisms of severe COVID-19 disease.
The quest to identify mechanisms that might be contributing to death in COVID-19: Why do some patients die from this disease, while others — who appear to be just as ill do not?
Researchers at Massachusetts General Hospital (MGH) and the Broad Institute of MIT and Harvard have identified the protein “signature” of severe COVID-19
Interest was to develop methods for studying human immune responses to infections, which they had applied to the condition known as bacterial sepsis. The three agreed to tackle this new problem with the goal of understanding how the human immune system responds to SARS-CoV-2, the novel pathogen that causes COVID-19.
How scientists launched a study in days to probe COVID-19’s unpredictability
Collecting these specimens required a large team of collaborators from many departments, which worked overtime for five weeks to amass blood samples from 306 patients who tested positive for COVID-19, as well as from 78 patients with similar symptoms who tested negative for the coronavirus.
Credit : Alexandra-Chloé VillaniResearch associates at Mass General who worked countless hours to process blood samples for the COVID Acute Cohort Study (from left to right: Anna Gonye, Irena Gushterova, and Tom Lasalle)By Leah Eisenstadt
As the COVID-19 surge began in March, Mass General and Broad researchers worked around the clock to begin learning why some patients fare worse with the disease than others
The study found that most patients with COVID-19 have a consistent protein signature, regardless of disease severity; as would be expected, their bodies mount an immune response by producing proteins that attack the virus. “But we also found a small subset of patients with the disease who did not demonstrate the pro-inflammatory response that is typical of other COVID-19 patients,” Filbin said, yet these patients were just as likely as others to have severe disease. Filbin, who is also an assistant professor of emergency medicine at Harvard Medical School (HMS), noted that patients in this subset tended to be older people with chronic diseases, who likely had weakened immune systems.
Among other revelations, this showed that the most prevalent severity-associated protein, a pro-inflammatory protein called interleukin-6 (IL-6) rose steadily in patients who died, while it rose and then dropped in those with severe disease who survived. Early attempts by other groups to treat COVID-19 patients experiencing acute respiratory distress with drugs that block IL-6 were disappointing, though more recent studies show promise in combining these medications with the steroid dexamethasone.
Hacohen, who is a professor of medicine at HMS and director of the Broad’s Cell Circuits Program:
“You can ask which of the many thousands of proteins that are circulating in your blood are associated with the actual outcome,” he said, “and whether there is a set of proteins that tell us something.”
Goldberg, who is a professor of emergency medicine at HMS:
They are highly likely to be useful in figuring out some of the underlying mechanisms that lead to severe disease and death in COVID-19,” she said, noting her gratitude to the patients involved in the study. Their samples are already being used to study other aspects of COVID-19, such as identifying the qualities of antibodies that patients form against the virus.
Thriving Vaccines and Research: Weizmann Institute Coronavirus Research Development
Reporter:Amandeep Kaur, B.Sc., M.Sc.
In early February, Prof. Eran Segal updated in one of his tweets and mentioned that “We say with caution, the magic has started.”
The article reported that this statement by Prof. Segal was due to decreasing cases of COVID-19, severe infection cases and hospitalization of patients by rapid vaccination process throughout Israel. Prof. Segal emphasizes in another tweet to remain cautious over the country and informed that there is a long way to cover and searching for scientific solutions.
A daylong webinar entitled “COVID-19: The epidemic that rattles the world” was a great initiative by Weizmann Institute to share their scientific knowledge about the infection among the Israeli institutions and scientists. Prof. Gideon Schreiber and Dr. Ron Diskin organized the event with the support of the Weizmann Coronavirus Response Fund and Israel Society for Biochemistry and Molecular Biology. The speakers were invited from the Hebrew University of Jerusalem, Tel-Aviv University, the Israel Institute for Biological Research (IIBR), and Kaplan Medical Center who addressed the molecular structure and infection biology of the virus, treatments and medications for COVID-19, and the positive and negative effect of the pandemic.
The article reported that with the emergence of pandemic, the scientists at Weizmann started more than 60 projects to explore the virus from different range of perspectives. With the help of funds raised by communities worldwide for the Weizmann Coronavirus Response Fund supported scientists and investigators to elucidate the chemistry, physics and biology behind SARS-CoV-2 infection.
Prof. Avi Levy, the coordinator of the Weizmann Institute’s coronavirus research efforts, mentioned “The vaccines are here, and they will drastically reduce infection rates. But the coronavirus can mutate, and there are many similar infectious diseases out there to be dealt with. All of this research is critical to understanding all sorts of viruses and to preempting any future pandemics.”
The following are few important projects with recent updates reported in the article.
Mapping a hijacker’s methods
Dr. Noam Stern-Ginossar studied the virus invading strategies into the healthy cells and hijack the cell’s systems to divide and reproduce. The article reported that viruses take over the genetic translation system and mainly the ribosomes to produce viral proteins. Dr. Noam used a novel approach known as ‘ribosome profiling’ as her research objective and create a map to locate the translational events taking place inside the viral genome, which further maps the full repertoire of viral proteins produced inside the host.
She and her team members grouped together with the Weizmann’s de Botton Institute and researchers at IIBR for Protein Profiling and understanding the hijacking instructions of coronavirus and developing tools for treatment and therapies. Scientists generated a high-resolution map of the coding regions in the SARS-CoV-2 genome using ribosome-profiling techniques, which allowed researchers to quantify the expression of vital zones along the virus genome that regulates the translation of viral proteins. The study published in Nature in January, explains the hijacking process and reported that virus produces more instruction in the form of viral mRNA than the host and thus dominates the translation process of the host cell. Researchers also clarified that it is the misconception that virus forced the host cell to translate its viral mRNA more efficiently than the host’s own translation, rather high level of viral translation instructions causes hijacking. This study provides valuable insights for the development of effective vaccines and drugs against the COVID-19 infection.
Like chutzpah, some things don’t translate
Prof. Igor Ulitsky and his team worked on untranslated region of viral genome. The article reported that “Not all the parts of viral transcript is translated into protein- rather play some important role in protein production and infection which is unknown.” This region may affect the molecular environment of the translated zones. The Ulitsky group researched to characterize that how the genetic sequence of regions that do not translate into proteins directly or indirectly affect the stability and efficiency of the translating sequences.
Initially, scientists created the library of about 6,000 regions of untranslated sequences to further study their functions. In collaboration with Dr. Noam Stern-Ginossar’s lab, the researchers of Ulitsky’s team worked on Nsp1 protein and focused on the mechanism that how such regions affect the Nsp1 protein production which in turn enhances the virulence. The researchers generated a new alternative and more authentic protocol after solving some technical difficulties which included infecting cells with variants from initial library. Within few months, the researchers are expecting to obtain a more detailed map of how the stability of Nsp1 protein production is getting affected by specific sequences of the untranslated regions.
The landscape of elimination
The article reported that the body’s immune system consists of two main factors- HLA (Human Leukocyte antigen) molecules and T cells for identifying and fighting infections. HLA molecules are protein molecules present on the cell surface and bring fragments of peptide to the surface from inside the infected cell. These peptide fragments are recognized and destroyed by the T cells of the immune system. Samuels’ group tried to find out the answer to the question that how does the body’s surveillance system recognizes the appropriate peptide derived from virus and destroy it. They isolated and analyzed the ‘HLA peptidome’- the complete set of peptides bound to the HLA proteins from inside the SARS-CoV-2 infected cells.
After the analysis of infected cells, they found 26 class-I and 36 class-II HLA peptides, which are present in 99% of the population around the world. Two peptides from HLA class-I were commonly present on the cell surface and two other peptides were derived from coronavirus rare proteins- which mean that these specific coronavirus peptides were marked for easy detection. Among the identified peptides, two peptides were novel discoveries and seven others were shown to induce an immune response earlier. These results from the study will help to develop new vaccines against new coronavirus mutation variants.
Gearing up ‘chain terminators’ to battle the coronavirus
Prof. Rotem Sorek and his lab discovered a family of enzymes within bacteria that produce novel antiviral molecules. These small molecules manufactured by bacteria act as ‘chain terminators’ to fight against the virus invading the bacteria. The study published in Nature in January which reported that these molecules cause a chemical reaction that halts the virus’s replication ability. These new molecules are modified derivates of nucleotide which integrates at the molecular level in the virus and obstruct the works.
Prof. Sorek and his group hypothesize that these new particles could serve as a potential antiviral drug based on the mechanism of chain termination utilized in antiviral drugs used recently in the clinical treatments. Yeda Research and Development has certified these small novel molecules to a company for testing its antiviral mechanism against SARS-CoV-2 infection. Such novel discoveries provide evidences that bacterial immune system is a potential repository of many natural antiviral particles.
Resolving borderline diagnoses
Currently, Real-time Polymerase chain reaction (RT-PCR) is the only choice and extensively used for diagnosis of COVID-19 patients around the globe. Beside its benefits, there are problems associated with RT-PCR, false negative and false positive results and its limitation in detecting new mutations in the virus and emerging variants in the population worldwide. Prof. Eran Elinavs’ lab and Prof. Ido Amits’ lab are working collaboratively to develop a massively parallel, next-generation sequencing technique that tests more effectively and precisely as compared to RT-PCR. This technique can characterize the emerging mutations in SARS-CoV-2, co-occurring viral, bacterial and fungal infections and response patterns in human.
The scientists identified viral variants and distinctive host signatures that help to differentiate infected individuals from non-infected individuals and patients with mild symptoms and severe symptoms.
In Hadassah-Hebrew University Medical Center, Profs. Elinav and Amit are performing trails of the pipeline to test the accuracy in borderline cases, where RT-PCR shows ambiguous or incorrect results. For proper diagnosis and patient stratification, researchers calibrated their severity-prediction matrix. Collectively, scientists are putting efforts to develop a reliable system that resolves borderline cases of RT-PCR and identify new virus variants with known and new mutations, and uses data from human host to classify patients who are needed of close observation and extensive treatment from those who have mild complications and can be managed conservatively.
Moon shot consortium refining drug options
The ‘Moon shot’ consortium was launched almost a year ago with an initiative to develop a novel antiviral drug against SARS-CoV-2 and was led by Dr. Nir London of the Department of Chemical and Structural Biology at Weizmann, Prof. Frank von Delft of Oxford University and the UK’s Diamond Light Source synchroton facility.
To advance the series of novel molecules from conception to evidence of antiviral activity, the scientists have gathered support, guidance, expertise and resources from researchers around the world within a year. The article reported that researchers have built an alternative template for drug-discovery, full transparency process, which avoids the hindrance of intellectual property and red tape.
The new molecules discovered by scientists inhibit a protease, a SARS-CoV-2 protein playing important role in virus replication. The team collaborated with the Israel Institute of Biological Research and other several labs across the globe to demonstrate the efficacy of molecules not only in-vitro as well as in analysis against live virus.
Further research is performed including assaying of safety and efficacy of these potential drugs in living models. The first trial on mice has been started in March. Beside this, additional drugs are optimized and nominated for preclinical testing as candidate drug.
Why wait for more info? A new case of cerebral sinus venus thrombosis was reported in a 25 year old man who became critically ill from a cerebral hemorrhage. And for women age 20-50, CSVT occurred in 1 in 13,000, or 4-15X higher than background.
UPDATED on 4/14/2021
How UK doctor linked rare blood-clotting to AstraZeneca Covid jab
We have put together the following mechanism for thrombosis including central vein sinus thrombosis as a complication of both J&J and the AstraZeneca vaccines. This unifying mechanism explains the predilection of cerebral veins and higher risk in younger women. Please share your thoughts on the proposed mechanism.
We have submitted the attached manuscript to SSRN. Sharing this promptly considering the public health significance.
Thanks
Figure 1. AstraZeneca or Janssen COVID-19 vaccine induced thromboinflammation and cerebral venous sinus thrombosis (CVST)-Proposed Mechanisms: Adenovirus carrier delivers SARS-CoV-2 DNA encoding the Spike (S) protein to the lung megakaryocytes via the coxsackie-adenovirus receptor (CAR). Spike protein induces COX-2 expression in megakaryocytes leading to megakaryocyte activation, biogenesis of activated platelets that express COX-2 and generate thromboxane A2 (TxA2). Cerebral vein sinus endothelial cells express podoplanin, a natural ligand for CLEC2 receptors on platelets. Platelets traversing through the cerebral vein sinuses would be further activated by TxA2 dependent podoplanin-CLEC2 signaling, leading to release of extracellular vesicles, thereby promoting CLEC5A and TLR2 mediated neutrophil activation, thromboinflammation, CVST, and thromboembolism in other vascular beds. Young age and female gender are associated with increased TxA2 generation and platelet activation respectively, and hence increased risk of thromboembolic complications following vaccination.
Best regards,
Ajay
Ajay Gupta, M.B.,B.S., M.D.
Clinical Professor,
Division of Nephrology, Hypertension and Kidney Transplantation
University of California Irvine
President & CSO, KARE Biosciences (www.karebio.com)
Title: SARS-CoV-2 vaccination induced thrombosis: Is chemoprophylaxis with antiplatelet agents warranted?
Guest Authors:
Kate Chander Chiang1
Ajay Gupta, MBBS, MD1,2
Affiliations
(1) KARE Biosciences, Orange, CA 92869
(2) Department of Medicine, University of California Irvine (UCI) School of Medicine, Orange, CA 92868
*Corresponding author:
Ajay Gupta, MBBS, MD
Clinical Professor of Medicine,
Division of Nephrology, Hypertension and Kidney Transplantation
University of California Irvine (UCI) School of Medicine,
Orange, CA 92868
Tel: +1 (562) 412-6259
E-mail: ajayg1@hs.uci.edu
Word Count
Abstract: 359
Main Body: 1,648
Funding: No funding was required.
Conflict of Interest: AG and KCC have filed a patent for use of Ramatroban as an anti-thrombotic and immune modulator in SARS-CoV-2 infection. The patents have been licensed to KARE Biosciences. KCC is an employee of KARE Biosciences.
Author Contributions: AG and KCC conceptualized, created the framework, wrote and reviewed the manuscript.
The COVID-19 vaccines, Vaxzevria® (AstraZeneca) and the Janssen vaccine (Johnson & Johnson) are highly effective but associated with rare thrombotic complications. These vaccines are comprised of recombinant, replication incompetent, chimpanzee adenoviral vectors encoding the Spike (S) glycoprotein of SARS-CoV-2. The adenovirus vector infects epithelial cells expressing the coxsackievirus and adenovirus receptor (CAR). The S glycoprotein of SARS-CoV-2 is expressed locally stimulating neutralizing antibody and cellular immune responses, which protect against COVID-19. The immune responses are highly effective in preventing symptomatic disease in adults irrespective of age, gender or ethnicity. However, both vaccines have been associated with thromboembolic events including cerebral venous sinus thrombosis (CVST). Megakaryocytes also express CAR, leading us to postulate adenovirus vector uptake and expression of spike glycoprotein by megakaryocytes. Spike glycoprotein induces expression of cyclooxygenase -2 (COX-2), leading to generation of thromboxane A2 (TxA2). TxA2 promotes megakaryocyte activation, biogenesis of activated platelets and thereby increased thrombogenicity. Cerebral vein sinus endothelial cells express podoplanin, a natural ligand for CLEC2 receptors on platelets. Platelets traversing through the cerebral vein sinuses would be further activated by TxA2 dependent podoplanin-CLEC2 signaling, leading to CVST. The mechanisms proposed are consistent with the following clinical observations. First, a massive increase in TxA2 generation promotes platelet activation and thromboinflammation in COVID-19 patients. Second, TxA2 generation and platelet activation is increased in healthy women compared to men, and in younger mice compared to older mice; and, younger age and female gender appear to be associated with increased risk of thromboembolism as a complication of adenoviral vector based COVID-19 vaccine. The roll out of both AstraZeneca and Janssen vaccines has been halted for adults under 30-60 years of age in many countries. We propose that antiplatelet agents targeting TxA2 receptor signaling should be considered for chemoprophylaxis when administering the adenovirus based COVID-19 vaccines to adults under 30-60 years of age. In many Asian and African countries, only adenovirus-based COVID-19 vaccines are available at present. A short course of an antiplatelet agent such as aspirin could allow millions to avail of the benefits of the AstraZeneca and Janssen COVID-19 vaccines which could be otherwise either denied to them or put them at undue risk of thromboembolic complications.
COVID-19 disease is caused by a novel positive-strand RNA coronavirus (SARS-CoV-2), which belongs to the Coronaviridae family, along with the severe acute respiratory syndrome (SARS) and the Middle East respiratory syndrome (MERS) coronaviruses.1 The genome of these viruses encodes several non-structural and structural proteins, including spike (S), envelope (E), membrane (M), and nucleocapsid (N) proteins.2 The majority of the vaccines for COVID-19 that employ administration of viral antigens or viral gene sequences aim to induce neutralizing antibodies against the viral spike protein (S), preventing uptake through the ACE2 receptor, and thereby blocking infection.3
The Janssen COVID-19 vaccine (Johnson & Johnson) is comprised of a recombinant, replication- incompetent Ad26 vector, encoding a stabilized variant of the SARS-CoV-2 Spike (S) protein. The ChAdOx1 nCoV-19 vaccine (AZD1222, Vaxzevria®) was developed at Oxford University and consists of a replication-deficient chimpanzee adenoviral vector ChAdOx1, encoding the S protein.4 In US Phase III trials, Vaxzevria has been demonstrated to have 79% efficacy at preventing symptomatic COVID-19, and 100% efficacy against severe or critical disease and hospitalization, with comparable efficacy across ethnicity, gender and age.5 However, Vaxzevria has been associated with thrombotic and embolic events including disseminated intravascular coagulation (DIC) and cerebral venous sinus thrombosis (CVST), occurring within 14 days after vaccination, mostly in people under 55 years of age, the majority of whom have been women.6 Data from Europe suggests that the event rate for thromboembolic events may be about 10 per million vaccinated. Antibodies to platelet factor 4/heparin complexes have been recently reported in a few patients.7 However, the significance of this finding remains to be established. As of April 12, 2021, about 6.8 million doses of the Janssen vaccine have been administered in the U.S.8 CDC and FDA are reviewing data involving six reported U.S. cases of CVST in combination with thrombocytopenia.8 All six cases occurred among women between the ages of 18 and 48, and symptoms occurred 6 to 13 days after vaccination.8
SARS-CoV-2 is known to cause thromboinflammation leading to thrombotic microangiopathy, pulmonary thrombosis, pedal acro-ischemia (“COVID-toes”), arterial clots, strokes, cardiomyopathy, coronary and systemic vasculitis, deep venous thrombosis, pulmonary embolism, and microvascular thrombosis in renal, cardiac and brain vasculature.9-14 Cerebral venous sinus thrombosis (CVST) has also been reported in COVID-19 patients.15 Amongst 34,331 hospitalized COVID-19 patients, CVST was diagnosed in 28.16 In a multicenter, multinational, cross sectional, retrospective study of 8 patients diagnosed with CVST and COVID-19, seven were women.17 In another series of 41 patients with COVID-19 and CVST, the average age was about 50 years (SD, 16.5 years).17 The pathobiology of thrombotic events associated with the AstraZeneca vaccine should be viewed in the context of mechanisms underlying thromboinflammation that complicates SARS-CoV-2 infection and COVID-19 disease.
A. Role of COX-2 and thromboxane A2 in thromboinflammation complicating adenovirus based COVID-19 vaccine encoding the Spike protein of SARS-CoV-2
Thromboinflammation in COVID-19 seems to be primarily caused by endothelial, platelet and neutrophil activation, platelet-neutrophil aggregates and release of neutrophil extracellular traps (NETs).13,18 Platelet activation in COVID-19 is fueled by a lipid storm characterized by massive increases in thromboxane A2 (TxA2) levels in the blood and bronchoalveolar lavage fluid.19,20 Cyclooxygenase (COX) enzymes catalyze the first step in the biosynthesis of TxA2 from arachidonic acid, and COX-2 expression is induced by the spike (S) protein of coronaviruses.21 We postulate that an aberrant increase in TxA2 generation induced by the spike protein expression from the AstraZeneca vaccine leads to thromboinflammation, thromboembolism and CVST. 4
The support for the above proposed mechanism comes from the following observations. First, when mice of different age groups were infected with SARS-CoV virus, the generation of TxA2 was markedly increased in younger mice compared to middle aged mice.22 Furthermore, in children with asymptomatic or mildly symptomatic SARS-CoV-2 infection, microvascular thrombosis and thrombotic microangiopathy occur early in infection.20 These observations are consistent with the higher risk for thrombosis in adults under 60 years of age, compared with the older age group.6,7 Second, platelets from female mice are much more reactive than from male mice.23 Furthermore, TxA2 generation, TxA2-platelet interaction and activation is increased in women compared to men.24,25 These observations are consistent with disproportionately increased risk of thrombosis in women following AstraZeneca and Janssen COVID-19 vaccines.
The adenoviral vector ChAdOx1, containing nCoV-19 spike protein gene, infects host cells through the coxsackievirus and adenovirus receptor (CAR).26 CAR-dependent cell entry of the viral vector allows insertion of the SARS-CoV-2 spike protein gene and expression of Spike protein by host cells (Figure 1). CAR is primarily expressed on epithelial tight junctions.27 CAR expression has also been reported in platelets,28 and since platelets are anucleate cells CAR expression by megakaryocytes can be inferred. Therefore, AstraZeneca and Janssen vaccines would be expected to induce expression of Spike protein in megakaryocytes and platelets (Figure 1).
Spike protein of coronaviruses in known to induce COX-2 gene expression.21,29 COX-2 expression is induced during normal human megakaryopoiesis and characterizes newly formed platelets.30 While in healthy controls <10% of circulating platelets express COX-2, in patients with high platelet generation, up to 60% of platelets express COX-2.30 Generation of TxA2 by platelets is markedly suppressed by COX-2 inhibition in patients with increased megakaryopoiesis versus healthy subjects.30 Therefore, we postulate that expression of Spike protein induces COX-2 expression and generation of thromboxane A2 by megakaryocytes. TxA2 promotes biogenesis of activated platelets expressing COX-2. Platelet TxA2 generation leads to platelet activation and aggregation, and thereby thromboinflammation (Figure 1).
Extravascular spaces of the lungs comprise populations of mature and immature megakaryocytes that originate from the bone marrow, such that lungs are a major site of platelet biogenesis, accounting for approximately 50% of total platelet production or about 10 million platelets per hour.31 More than 1 million extravascular megakaryocytes have been observed in each lung of transplant mice.31 Following intramuscular injection of the AstraZeneca and Janssen vaccines, the adenovirus vector will traverse the veins and lymphatics to be delivered to the pulmonary circulation thereby exposing lung megakaryocytes in the first pass. Interestingly, under thrombocytopenic conditions, haematopoietic progenitors migrate out of the lung to repopulate the bone marrow and completely reconstitute blood platelet counts.31
B. Predilection of cerebral venous sinuses for thrombosis following vaccination
Recent studies have demonstrated that arterial, venous and sinusoidal endothelial cells in the brain uniquely express markers of the lymphatic endothelium including podoplanin.32 Podoplanin serves as a ligand for CLEC2 receptors on platelets.33 Thromboxane A2 dependent CLEC2 signaling leads to platelet activation (Figure 1), while a TxA2 receptor antagonist nearly abolish CLEC2 signaling and platelet activation.33 TxA2 dependent CLEC2 signaling promotes release of exosomes and microvesicles from platelets, leading to activation of CLEC5A and TLR2 receptors respectively on neutrophils, neutrophil activation and release of neutrophil extracellular traps (NETs) (Figure 1).34 Neutrophil activation, more than platelet activation, is associated with thrombotic complications in COVID-19.13,18,35 As proposed above, the expression of podoplanin, a unique molecular signature of cerebral endothelial cells, may be responsible for the predilection of brain vascular bed to thromboinflammation and CVST as a complication of COVID-19 vaccines. 5
C. Chemoprophylaxis with antiplatelet agents
In animal models of endotoxin mediated endothelial injury and thromboinflammation, antagonism of TxA2 signaling prevents ARDS, reduces myocardial damage and increases survival.36-38
Considering the key role played by platelets in thromboinflammation, we propose consideration of antiplatelet agents, either aspirin or TxA2 receptor antagonists, as chemoprophylactic agents when the AstraZeneca vaccine is administered to adults between 18 and 60 years of age.39 High bleeding risk because of another medical condition or medication would be contraindications to use of antiplatelet agents.39 Medical conditions that increase bleeding risk include previous gastrointestinal bleeding, peptic ulcer disease, blood clotting problems, and kidney disease.39 Medications that increase bleeding risk include nonsteroidal anti-inflammatory drugs, steroids, and other anticoagulants or anti-platelet agents.39 Aspirin appears to be safe in COVID-19. In a retrospective observational study in hospitalized patients with COVID-19, low-dose aspirin was found to be effective in reducing morbidity and mortality; and was not associated with any safety issues including major bleeding.40 Therefore, aspirin is likely to be safe as an adjunct to COVID-19 vaccines even in the event of a subsequent infection with SARS-CoV-2 virus.
Can aspirin influence the host immune response to the COVID-19 vaccines? This issue merits further investigation. When healthy adults > 65 years of age were given influenza vaccine and randomized to receive 300 mg aspirin or placebo on days 1, 2, 3, 5 and 7, the aspirin group showed 4-fold or greater rise in influenza specific antibodies.41 The risk-benefit analysis, based on above information, suggests that a one to three week course of low-dose aspirin merits consideration in order to prevent the thromboembolic events associated with the AstraZeneca vaccine.
SUMMARY
Thromboembolic disease including disseminated intravascular coagulation and cerebral venous sinus thrombosis have been reported in association with AstraZeneca and Janssen COVID-19 vaccines. Many countries have halted use of these vaccines either entirely or for adults under 30 to 60 years of age. European and North American countries generally have access to mRNA vaccines. However, in Asian and African countries the choices are limited to adenovirus based COVID-19 vaccines. The governments in such countries are forging ahead with vaccinating all adults, including those under 60 years of age, with Vaxzevria, Covishield (the version of Vaxzevria manufactured by the Serum Institute of India) or the Janssen vaccines. This has led to grave concern and anxiety amongst the citizens and medical professionals. Considering the profound global public health implications of limiting the use of these vaccines, it is critical to understand the pathobiology of vaccination induced thrombotic events in order to guide strategies aimed at prevention. In this regard, studies are urgently needed to examine lipid mediators and thromboxane A2 – platelet axis following vaccination with these vaccines, compared with mRNA vaccines. The risk-benefit analysis based on information presented here suggests that chemoprophylaxis using a short course of low-dose aspirin in adults under 60 years of age may be justified in conjunction with adenovirus based COVID-19 vaccines in order to prevent thromboembolic events and enhance safety. 6
Figure 1. AstraZeneca or Janssen COVID-19 vaccine induced thromboinflammation and cerebral venous sinus thrombosis (CVST)-Proposed Mechanisms: Adenovirus carrier delivers SARS-CoV-2 DNA encoding the Spike (S) protein to the lung megakaryocytes via the coxsackie-adenovirus receptor (CAR). Spike protein induces COX-2 expression in megakaryocytes leading to megakaryocyte activation, biogenesis of activated platelets that express COX-2 and generate thromboxane A2 (TxA2). Cerebral vein sinus endothelial cells express podoplanin, a natural ligand for CLEC2 receptors on platelets. Platelets traversing through the cerebral vein sinuses would be further activated by TxA2 dependent podoplanin-CLEC2 signaling, leading to release of extracellular vesicles, thereby promoting CLEC5A and TLR2 mediated neutrophil activation, thromboinflammation, CVST, and thromboembolism in other vascular beds. Young age and female gender are associated with increased TxA2 generation and platelet activation respectively, and hence increased risk of thromboembolic complications following vaccination.
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Subject: APRIL 13. 2021 – J&J Statement – Out of an abundance of caution, the CDC and FDA have recommended a pause in the use of our vaccine. ->> Are there relations between these FINDINGS?
Johnson & Johnson Statement on COVID-19 Vaccine
NEW BRUNSWICK, N.J., April 13, 2021– The safety and well-being of the people who use our products is our number one priority. We are aware of an extremely rare disorder involving people with blood clots in combination with low platelets in a small number of individuals who have received our COVID-19 vaccine. The United States Centers for Disease Control (CDC) and Food and Drug Administration (FDA) are reviewing data involving six reported U.S. cases out of more than 6.8 million doses administered. Out of an abundance of caution, the CDC and FDA have recommended a pause in the use of our vaccine.
In addition, we have been reviewing these cases with European health authorities. We have made the decision to proactively delay the rollout of our vaccine in Europe.
We have been working closely with medical experts and health authorities, and we strongly support the open communication of this information to healthcare professionals and the public.
The CDC and FDA have made information available about proper recognition and management due to the unique treatment required with this type of blood clot. The health authorities advise that people who have received our COVID-19 vaccine and develop severe headache, abdominal pain, leg pain, or shortness of breath within three weeks after vaccination should contact their health care provider.
For more information on the Janssen COVID-19 vaccine, click here.
Please All send me your Expert Opinion on the relations between these FINDINGS?
Linking Thrombotic Thrombocytopenia to ChAdOx1 nCov-19 Vaccination, AstraZeneca | Leaders in Pharmaceutical Business Intelligence (LPBI) Group
Linking Thrombotic Thrombocytopenia to ChAdOx1 nCov-19 Vaccination, AstraZeneca
Reporter: Aviva Lev-Ari, PhD, RN
UPDATED on 4/13/2021
“Right now, these adverse events appear to be extremely rare,” Anne Schuchat, MD, principal deputy director of the CDC, and Peter Marks, MD, PhD, director of the FDA’s Center for Biologics Evaluation and Research, said in a joint statement from the two agencies. “COVID-19 vaccine safety is a top priority for the federal government, and we take all reports of health problems following COVID-19 vaccination very seriously.”
STATEMENT BY J&J
Johnson & Johnson Statement on COVID-19 Vaccine
NEW BRUNSWICK, N.J., April 13, 2021– The safety and well-being of the people who use our products is our number one priority. We are aware of an extremely rare disorder involving people with blood clots in combination with low platelets in a small number of individuals who have received our COVID-19 vaccine. The United States Centers for Disease Control (CDC) and Food and Drug Administration (FDA) are reviewing data involving six reported U.S. cases out of more than 6.8 million doses administered. Out of an abundance of caution, the CDC and FDA have recommended a pause in the use of our vaccine.
In addition, we have been reviewing these cases with European health authorities. We have made the decision to proactively delay the rollout of our vaccine in Europe.
We have been working closely with medical experts and health authorities, and we strongly support the open communication of this information to healthcare professionals and the public.
The CDC and FDA have made information available about proper recognition and management due to the unique treatment required with this type of blood clot. The health authorities advise that people who have received our COVID-19 vaccine and develop severe headache, abdominal pain, leg pain, or shortness of breath within three weeks after vaccination should contact their health care provider.
For more information on the Janssen COVID-19 vaccine, click here.
Thrombotic Thrombocytopenia after ChAdOx1 nCov-19 Vaccination, AstraZeneca
Several cases of unusual thrombotic events and thrombocytopenia have developed after vaccination with the recombinant adenoviral vector encoding the spike protein antigen of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) (ChAdOx1 nCov-19, AstraZeneca).
This study found that vaccination with ChAdOx1 nCov-19 can result in the rare development of immune thrombotic thrombocytopenia mediated by platelet-activating antibodies against PF4, which clinically mimics autoimmune heparin-induced thrombocytopenia (aHIT).
This study also found that the addition of immune globulin in doses that are readily achieved clinically was effective in inhibiting platelet activation by patients’ antibodies.
Clinician reluctance to start anticoagulation may be tempered by administering high-dose intravenous immune globulin to raise the platelet count, especially when a patient presents with severe thrombocytopenia and thrombosis, such as cerebral venous thrombosis.
Given the parallels with autoimmune heparininduced thrombocytopenia, anticoagulant options should include nonheparin anticoagulants used for the management of heparin-induced thrombocytopenia, unless a functional test has excluded heparin-dependent enhancement of platelet activation.
Finally, this paper suggest naming this novel entity vaccine-induced immune thrombotic thrombocytopenia (VITT) to avoid confusion with heparin-induced thrombocytopenia.
Subject: Fwd: Vaccination thrombotic events clinically mimics Heparin-induced thrombocytopenia | CD8+ Memory T Cell Responses against Viral Variants
Thrombotic Thrombocytopenia after ChAdOx1 nCov-19 Vaccination
This article was published on April 9, 2021, at NEJM.org. DOI: 10.1056/NEJMoa2104840
BACKGROUND Several cases of unusual thrombotic events and thrombocytopenia have developed after vaccination with the recombinant adenoviral vector encoding the spike protein antigen of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) (ChAdOx1 nCov-19, AstraZeneca). More data were needed on the pathogenesis of this unusual clotting disorder. METHODS We assessed the clinical and laboratory features of 11 patients in Germany and Austria in whom thrombosis or thrombocytopenia had developed after vaccination with ChAdOx1 nCov-19. We used a standard enzyme-linked immunosorbent assay to detect platelet factor 4 (PF4)–heparin antibodies and a modified (PF4-enhanced) platelet-activation test to detect platelet-activating antibodies under various reaction conditions. Included in this testing were samples from patients who had blood samples referred for investigation of vaccine-associated thrombotic events, with 28 testing positive on a screening PF4–heparin immunoassay. RESULTS Of the 11 original patients, 9 were women, with a median age of 36 years (range, 22 to 49). Beginning 5 to 16 days after vaccination, the patients presented with one or more thrombotic events, with the exception of 1 patient, who presented with fatal intracranial hemorrhage. Of the patients with one or more thrombotic events, 9 had cerebral venous thrombosis, 3 had splanchnic-vein thrombosis, 3 had pulmonary embolism, and 4 had other thromboses; of these patients, 6 died. Five patients had disseminated intravascular coagulation. None of the patients had received heparin before symptom onset. All 28 patients who tested positive for antibodies against PF4–heparin tested positive on the platelet-activation assay in the presence of PF4 independent of heparin. Platelet activation was inhibited by high levels of heparin, Fc receptor–blocking monoclonal antibody, and immune globulin (10 mg per milliliter). Additional studies with PF4 or PF4–heparin affinity purified antibodies in 2 patients confirmed PF4-dependent platelet activation. CONCLUSIONS Vaccination with ChAdOx1 nCov-19 can result in the rare development of immune thrombotic thrombocytopenia mediated by platelet-activating antibodies against PF4, which clinically mimics autoimmune heparin-induced thrombocytopenia. (Funded by the German Research Foundation.)
SOURCE
Thrombotic Thrombocytopenia after ChAdOx1 nCov-19 Vaccination
Andreas Greinacher, M.D., Thomas Thiele, M.D., Theodore E. Warkentin, M.D., Karin Weisser, Ph.D., Paul A. Kyrle, M.D., and Sabine Eichinger, M.D.
Author Affiliations
From Institut für Immunologie und Transfusionsmedizin, Universitätsmedizin Greifswald, Greifswald (A.G., T.T.), and the Division of Safety of Medicinal Products and Medical Devices, Paul-Ehrlich-Institut (Federal Institute for Vaccines and Biomedicines), Langen (K.W.) — both in Germany; the Departments of Pathology and Molecular Medicine and of Medicine, McMaster University, Hamilton, ON, Canada (T.E.W.); and the Department of Medicine I, Division of Hematology and Hemostaseology, Medical University of Vienna, Vienna (P.A.K., S.E.).
Address reprint requests to Dr. Greinacher at Institut für Immunologie und Transfusionsmedizin, Abteilung Transfusionsmedizin, Sauerbruchstrasse, 17487 Greifswald, Germany.
Mechanistic link between SARS-CoV-2 infection and increased risk of stroke using 3D printed models and human endothelial cells
Reporter: Adina Hazan, PhD
Kaneko, et al. from UCLA aimed to explore why SARS-CoV-2 infection is associated with an increased rate of cerebrovascular events, including
ischemic stroke and
intracerebral hemorrhage
While some suggested mechanisms include an overall systemic inflammatory response including increasing circulating cytokines and leading to a prothrombotic state, this may be only a partial answer. A SARS-CoV-2 specific mechanism could be likely, considering that both angiotensin-converting enzyme-2 (ACE2), the receptor necessary for SARS-CoV-2 to gain entry into the cell, and SARS-CoV-2 RNA have been reportedly detected in the human brain postmortem.
One of the difficulties in studying vasculature mechanisms is that the inherent 3D shape and blood flow subject this tissue to different stressors, such as flow, that could be critically relevant during inflammation. To accurately study the effect of SARS-CoV-2 on the vasculature of the brain, the team generated 3D models of the human middle cerebral artery during intracranial artery stenosis using data from CT (computed tomography) angiography. This data was then exported with important factors included such as
shear stress during perfusion,
streamlines, and
flow velocity to be used to fabricate 3D models.
These tubes were then coated with endothelial cells isolated and sorted from normal human brain tissue resected during surgery. In doing so, this model could closely mimic the cellular response of the vasculature of the human brain.
Surprisingly, without this 3D tube, human derived brain endothelial cells displayed very little expression of ACE2 or, TMPRSS2 (transmembrane protease 2), a necessary cofactor for SARS-COV-2 viral entry.
Interestingly,
horizontal shear stress increased the expression of ACE2 and
increased the binding of spike protein to ACE2, especially within the stenotic portion of the 3D model.
By exposing the endothelial cells to liposomes expressing the SARS-CoV-2 spike protein, they also were able to explore key upregulated genes in the exposed cells, in which they found that
“binding of SARS-CoV-2 S protein triggered 83 unique genes in human brain endothelial cells”.
This included many inflammatory signals, some of which have been previously described as associated with SARS-COV-2, and others whose effects are unknown. This may provide an important foundation for exploring potential therapeutic targets in patients susceptible to cerebrovascular events.
Overall, this study shows important links between the
mechanisms of SARS-CoV-2 and the
increase in ischemic events in these patients. It also has important implications for
treatment for SARS-CoV-2, as high blood pressure and atherosclerosis may be increasing ACE2 expression in patients, providing the entry port for viral particles into brain endothelia.
Detecting SARS-COV-2 antibodies in serum and plasma samples
Reporter: Irina Robu, PhD
Convalescent plasma therapy is a possible treatment under investigation where antibodies from recovered patients are transfused to current COVID-19 patients with the intent to help them fight the infection and buy time until their immune system can produce antibodies. Yet, not all recovered patients have the same quantity of antibody titers suitable for such transfusions. In some patients it will minimize the severity of the disease length.
The U.S. Food and Drug Administration authorized convalescent plasma therapy for patients with coronavirus disease 2019 and it permitted to be used during the pandemic because there is no approved treatment for COVID-19. The donated blood is processed to remove cells, leaving behind liquid and antibody.
Companies like Forte Bío are developing instruments such as Octet HTX Instrument, Octet RED384 Octet RED96e Instrument and Octet K2 Instrument to detect SARS-COV-2 antibodies in serum and plasma samples. The Octet technology allows quantification with high resolution comparable to an HPLC . The instrument utilizes BLI enabling label-free detection for protein quantitation and kinetic characterization at unmatched speed and throughput. The instrument can measure up to 96 samples simultaneously allowing both unlimited characterization capacity for various applications and custom assay tailoring to maximize analytical throughput or sensitivity and preventing bottlenecks.
How are antibodies tested ?
Immobilize a virus protein such as the receptor binding domain (RBD) of the SARS CoV-2 spike protein.
Dip the coronavirus biosensor into diluted patient plasma or serum samples.
Block the biosensor with non-relevant serum or blocking buffer if needed to prevent non-specific binding.
Even the researchers believe that the risk to donors is low, there are additional risks such as allergic reactions, lung damage, difficulty breathing or infections such as HIV, hepatitis B and Donated blood must be tested for safety prior to administering to patients.
What to expect ? It is up to the doctor treating the patient, if convalescent plasma therapy is an option. Even though data from clinical trials suggest that convalescent plasma may diminish the severity or duration of the COVID19, more research is needed to determine if convalescent plasma therapy is an effective treatment.
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