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J Thromb Haemost ; 18(9): 2103-2109, 2020 09.
Article in English | MEDLINE | ID: covidwho-1096903


The COVID-19 pandemic has become an urgent issue in every country. Based on recent reports, the most severely ill patients present with coagulopathy, and disseminated intravascular coagulation (DIC)-like massive intravascular clot formation is frequently seen in this cohort. Therefore, coagulation tests may be considered useful to discriminate severe cases of COVID-19. The clinical presentation of COVID-19-associated coagulopathy is organ dysfunction primarily, whereas hemorrhagic events are less frequent. Changes in hemostatic biomarkers represented by increase in D-dimer and fibrin/fibrinogen degradation products indicate the essence of coagulopathy is massive fibrin formation. In comparison with bacterial-sepsis-associated coagulopathy/DIC, prolongation of prothrombin time, and activated partial thromboplastin time, and decrease in antithrombin activity is less frequent and thrombocytopenia is relatively uncommon in COVID-19. The mechanisms of the coagulopathy are not fully elucidated, however. It is speculated that the dysregulated immune responses orchestrated by inflammatory cytokines, lymphocyte cell death, hypoxia, and endothelial damage are involved. Bleeding tendency is uncommon, but the incidence of thrombosis in COVID-19 and the adequacy of current recommendations regarding standard venous thromboembolic dosing are uncertain.

Blood Coagulation Disorders/blood , COVID-19/epidemiology , Disseminated Intravascular Coagulation/blood , Anticoagulants , Blood Coagulation , Blood Coagulation Disorders/complications , Blood Coagulation Tests , COVID-19/complications , Cytokines/metabolism , Disseminated Intravascular Coagulation/complications , Fibrin/chemistry , Fibrin Fibrinogen Degradation Products/metabolism , Fibrinogen/chemistry , Fibrinolysis , Hemorrhage , Hemostasis , Humans , Inflammation , Lung/metabolism , Lung/virology , Lymphocytes/metabolism , Partial Thromboplastin Time , Protease Inhibitors , Prothrombin Time , Sepsis , Thrombosis/metabolism
Med Hypotheses ; 144: 110030, 2020 Nov.
Article in English | MEDLINE | ID: covidwho-612684


Novel Coronavirus (SARS CoV-2), the etiological agent for the highly contagious Corona virus disease-2019 (COVID-19) pandemic has threatened global health and economy infecting around 5.8 million people and causing over 359,200 deaths (as of 28th May 2020, The clinical manifestations of infected patients generally range from asymptomatic or mild to severe illness, or even death. The ability of the virus to evade the host immune response have been major reasons for high morbidity and mortality. One of the important clinical observations under conditions of critical illness show increased risk of developing disseminated intravascular coagulation. Molecular mechanisms of how SARS CoV-2 induces such conditions still remain unclear. This report describes the presence of two unique motifs in the SARS CoV-2 nucleocapsid phosphoprotein (N-protein) that can potentially interact with fibrinogen and possibly prothrombin. This is based on an established function of secretory proteins in Staphylococcus aureus (S. aureus)-coagulase, Efb (Extracellular fibrinogen binding) and vWBP (von Willebrand factor Binding Protein), which are known to regulate the blood clotting cascade and the functions of host immune response. It is hypothesized that having protein interaction motifs that are homologous to these S. aureus proteins, the N-protein of this virus can mimic their functions, which may in turn play a crucial role in formation of blood clots in the host and help the virus evade host immune response. However, this hypothesis needs to be tested in vitro. Considering the overwhelming increase in the incidence of SARS CoV-2 infection globally, this information may be useful for further investigation and could help in deducing new therapeutic strategies to combat advanced stages of this disease.

Bacterial Proteins/chemistry , COVID-19/virology , Coronavirus Nucleocapsid Proteins/chemistry , Fibrinogen/chemistry , Host-Pathogen Interactions/immunology , SARS-CoV-2 , Amino Acid Motifs , COVID-19/metabolism , Humans , Immune System , Models, Theoretical , Peptides/chemistry , Phosphoproteins/chemistry , Protein Binding , Protein Domains , Staphylococcus aureus/enzymology , von Willebrand Factor/chemistry