📰 SARS-CoV2 virus hidden in blood platelets predicts entry into critical phase of COVID-19

© Morgane Bomsel

In a study published in the journal Cellular and Molecular Life Science, scientists show that the presence of the infectious SARS-CoV-2 virus in platelets is a predictive blood marker of a critical form of COVID-19. The platelets are then able to transfer the infection to the cells of innate immunity. This process can be blocked by a medication (A drug is a substance or composition presented as possessing…) anti-platelet agent used in cardiology (Cardiology is the medical specialty that studies the heart and its…): l’Abciximab.

Despite the vaccination (Vaccination is a process of introducing an external agent (the…) and the development of symptomatic treatments approximately 5 to 10% of people with Covid-19 progress to a severe or critical form. These patients mainly develop pneumonia (A pneumopathy is a pathology of the lung tissue. Etymologically, it is a…) severe that progresses to syndrome (A syndrome is a set of clinical signs and symptoms that a patient is susceptible to…) acute respiratory distress accompanied by the spread of virus (A virus is a biological entity that requires a host cell, which it uses…) airways to other sites, targeting innate immune cells such as macrophages. Respiratory aggravation usually occurs during second (Second is the feminine of the adjective second, which comes immediately after the first or which…) week after the first symptoms appear. It coincides with coagulation disorders including episodes of micro-aggregation of poorly understood platelets, particularly in the lungs, even in people with no history of sickness (Disease is an alteration of the functions or health of a living organism, animal…) cardiovascular. However, the treatment anticoagulant (An anticoagulant is a chemical substance having the property of inhibiting the…) of COVID-19 patients is of limited effectiveness.

To their essential role in haemostasis, platelets combine well-established immunological functions contributing to theinflammation (Inflammation is a stereotypical immune defense reaction of the…) and can in certain viral pathologies, harbor and transport viruses. In addition, recent studies have shown that megakaryocytes, the precursor cells of platelets, are able to migrate from bone marrow (The bone marrow is tissue located in the center of the bones. There are two forms: the yellow marrow…) where they originate, to the lungs where they locally produce platelets. These end their short vie (Life is the name given 🙂 captured by innate immune cells (macrophages) which they activate. Platelets could therefore be involved in the pathophysiology of severe COVID in several ways: in the genesis of hemostasis disorders (thromboses); by promoting viral dissemination during their circulation (Road traffic (Anglicism: road traffic) is the movement of motor vehicles…) ubiquitous; finally in “thethunderstorm (A storm, from the old French ore which meant wind, is a disturbance…) cytokinique” sets off (A triggered (or snap roll) is an aerobatic figure.) by the macrophages that they will have activated.

How to predict that a patient (In the field of medicine, the term patient commonly refers to a person receiving…) with COVID-19 is at risk of a fatal outcome? To answer this decisive question in taking into account charge (The payload represents what is actually…) individual and the prognosis of patients, the scientists hypothesized that platelets, derived from megakaryocytes infected with SARS-CoV-2 in the marrow or lungs, could carry viruses contributing to hemostasis disorders and dissemination observed in COVID-19 and could contribute to the critical development of the disease. In fact, in seriously ill patients, the researchers were able to show that in the autopsy tissues, the megakaryocytes of the marrow and of the pulmonary capillaries were infected. These infected megakaryocytes are capable of producing infected platelets which reach the lungs where, by interacting with the pulmonary macrophages, they trigger a cytokine storm rich in factors affecting the integrity of the vessels and in inflammatory molecules.

The detection of these infected platelets in the sang (Blood is a liquid connective tissue made up of free cell populations, including the…) of patients with severe COVID-19 in the first two weeks after the onset of the first symptoms, is a predictive marker of fatal outcome in almost all patients (in 19 out of 20 cases analyzed). In addition, the viruses contained in the platelets retain their infectious character. Once captured by macrophages, infected platelets transmit the infection to them in vitro according to a process that is blocked by targeting the protein (A protein is a biological macromolecule composed of one or more…) GPIIbIIIa at the surface (A surface generally refers to the superficial layer of an object. The term a…) of the platelet by the antiplatelet agent Abciximab.

Scientists point to the immunological role of platelets and their major involvement in severe COVID-19 at three levels: i) everything (The all-inclusive as the whole of what exists is often interpreted as the world or…) first in hemostasis disorders with the formation of the thrombus (clot blocking the vessels), ii) in viral dissemination where platelets are a cheval (Le cheval (wild horse or horse horse) is a grand mammifer herbivore and… Trojan for the infectious virus, protecting it from being destroyed by the immune system (The immune system of an organism is a coordinated set of elements of…) and iii) la storm (A storm is a violent weather phenomenon with broad…) exacerbated by cytokines. These adverse effects could be clinically targeted all at once using specific anti-platelet drugs, which would increase the chances of patient survival. The researchers’ results also make it possible to predict the fatal prognosis early enough to anticipate appropriate medical management.

Platelets infected with SARS-CoV-2 are a therapeutic target towards which convergent (in astronautics, convergent in mathematics, convergent sequence convergent series…) the multiple clinical manifestations of critical COVID-19.
1- In the marrow, SARS-CoV-2 infects megakaryocytes and accelerates their differentiation. These migrate to the lungs where they produce virus-containing platelets in the circulation pulmonary (The lungworts are plants of the Boraginaceae family belonging to the genus…).
2- These infectious platelets disseminate the virus to other sites by infecting the cells of innate immunity.
3- Overactivated platelets contribute to inflammation systemic (The systemic – from the Greek “systema”, “together…) and to thrombus formation seen in complications of severe COVID-19.
4- The cytokine storm enriched with inflammatory molecules and cytokines affecting the integrity of the surface of the pulmonary vessels and alveoli, allows platelets to penetrate the pulmonary tissue and infect the alveolar macrophages.
© Morgane Bomsel Fernando Real.

To know more:

Infection of lung megakaryocytes and platelets by SARS-CoV-2 anticipate fatal COVID-19
Zhu A, Real R; Capron C, Rosenberg A, Zhu J, Cottignies-Calamarte A, Massé JM, Moine P, Bessis S, Godement M, Geri G, Chiche JD, Valdebenito S, Belouzard S, Dubuisson J Lorin de la Grandmaison G, Eugenin E, Chevret S, Annane D, Cramer-Bordé E, Bomsel M.
Cell Mol Life Sciences 16 juin 2022. https://doi.org/10.1007/s00018-022-04318-x

Entrée mucosa (The mucous membranes (from the Latin mucus) are thin layers of tissue of ectodermal origin…) of HIV and mucosal immunity (Institut Cochin/CNRS/Inserm/University of Paris (Paris is a French city, capital of France and the capital of the region…) Cité). 22 rue (The street is a circulation space in the city that serves housing and places…) Mechain. 75014 Paris.

Morgane Bomsel – Director of research (Scientific research designates in the first place all the actions undertaken with a view to…) CNRS (The National Center for Scientific Research, better known by its acronym CNRS, is the largest…) at theinstitut (An institute is a permanent organization created for a certain purpose. It is…) Cochin – morgane.bomsel at inserm.fr

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