Introduction Coagulation dysfunction and thromboembolism emerge as strong comorbidity factors in severe COVID‐19. However, it is unclear when particularly platelet activation markers and coagulation factors dysregulated during the pathogenesis of COVID‐19. Here, we sought to assess the levels of coagulation and platelet activation markers at moderate and severe stages of COVID‐19 to understand the pathogenesis. Methods To understand this, hospitalized COVID‐19 patients with (severe cases that required intensive care) or without pneumonia (moderate cases) were recruited. Phenotypic and molecular characterizations were performed employing basic coagulation tests including prothrombin time (PT), activated partial thromboplastin time (APTT), D‐Dimer, and tissue factor pathway inhibitor (TFPI). The flow cytometry‐based multiplex assays were performed to assess FXI, anti‐thrombin, prothrombin, fibrinogen, FXIII, P‐selectin, sCD40L, plasminogen, tissue plasminogen activator (tPA), plasminogen activator inhibitor‐1 (PAI‐1), and D‐Dimer. Results The investigations revealed induction of plasma P‐selectin and CD40 ligand (sCD40L) in moderate COVID‐19 cases, which were significantly abolished with the progression of COVID‐19 severity. Moreover, a profound reduction in plasma tissue factor pathway inhibitor (TFPI) and FXIII were identified particularly in the severe COVID‐19. Further analysis revealed fibrinogen induction in both moderate and severe patients. Interestingly, an elevated PAI‐1 more prominently in moderate, and tPA particularly in severe COVID‐19 cases were observed. Particularly, the levels of fibrinogen and tPA directly correlated with the severity of the disease. Conclusions In summary, induction of soluble P‐selectin, sCD40L, fibrinogen, and PAI‐1 suggests the activation of platelets and coagulation system at the moderate stage before COVID‐19 patients require intensive care. These findings would help in designing better thromboprophylaxis to limit the COVID‐19 severity.

Severe coronavirus (SARS-COV-2) infection often leads to systemic inflammation accompanied by cardiovascular complications including venous thromboembolism (VTE). However, it is largely undefined if inflammatory markers such as lipocalin-2 (LNC2), calprotectin (S100A8/A9), and cystatin C (CST3), previously linked with VTE, play roles in cardiovascular complications and advancement of COVID-19 severity. To investigate the same, hospitalized moderate and severe (presented pneumonia and required intensive care) COVID-19 patients were recruited. The levels of plasma LNC2, S100A8/A9, CST3, myoglobin, and cardiac Troponin I (cTnI) were assessed through enzyme-linked immunosorbent assay (ELISA). The investigation revealed a significantly upregulated level of plasma LNC2 at the moderate stage of SARS-CoV-2 infection. In contrast, the levels of S100A8/A9 and CST3 in moderate patients were comparable to healthy controls; however, a profound induction was observed only in severe COVID-19 patients. The tissue injury marker myoglobin was unchanged in moderate patients; however, a significantly elevated level was observed in the critically ill COVID-19 patients. In contrast, cTnI level was unchanged both in moderate and severe patients. Analysis revealed a positive correlation between the levels of S100A8/A9 and CST3 with myoglobin in COVID-19. In silico analysis predicted interactions of S100A8/A9 with toll-like receptor 4 (TLR-4), MyD88 LY96, and LCN2 with several other inflammatory mediators including MMP2, MMP9, TIMP1, and interleukins (IL-6, IL-17A, and IL-10). In summary, early induction of LCN2 likely plays a role in advancing the COVID-19 severity. A positive correlation of S100A8/A9 and CST3 with myoglobin suggests that these proteins may serve as predictive biomarkers for thromboembolism and tissue injury in COVID-19.

Cardiomyopathy is an irreparable loss and novel strategies are needed to induce resident cardiac progenitor cell (CPC) proliferation in situ to enhance the possibility of cardiac regeneration. Here, we sought to identify the potential roles of glycogen synthase kinase‐3β (GSK‐3β), a critical regulator of cell proliferation and differentiation, in CPC proliferation post‐myocardial infarction (MI). Cardiomyocyte‐specific conditional GSK‐3β knockout (cKO) and littermate control mice were employed and challenged with MI. Though cardiac left ventricular chamber dimension and contractile functions were comparable at 2 weeks post‐MI, cKO mice displayed significantly preserved LV chamber and contractile function versus control mice at 4 weeks post‐MI. Consistent with protective phenotypes, an increased percentage of c‐kit‐positive cells (KPCs) were observed in the cKO hearts at 4 and 6 weeks post‐MI which was accompanied by increased levels of cardiomyocyte proliferation. Further analysis revealed that the observed increased number of KPCs in the ischemic cKO hearts was mainly from a cardiac lineage, as the majority of identified KPCs were negative for the hematopoietic lineage marker, CD45. Mechanistically, cardiomyocyte‐GSK‐3β profoundly suppresses the expression and secretion of growth factors, including basic‐fibroblast growth factor, angiopoietin‐2, erythropoietin, stem cell factor, platelet‐derived growth factor‐BB, granulocyte colony‐stimulating factor, and vascular endothelial growth factor, post‐hypoxia. In conclusion, our findings strongly suggest that loss of cardiomyocyte‐GSK‐3β promotes cardiomyocyte and resident CPC proliferation post‐MI. The induction of cardiomyocyte and CPC proliferation in the ischemic cKO hearts is potentially regulated by autocrine and paracrine signaling governed by dysregulated growth factors post‐MI. A strategy to inhibit cardiomyocyte‐GSK‐3β could be helpful for the promotion of in situ cardiac regeneration post‐ischemic injury.

Coagulation dysfunction and thromboembolism emerge as strong comorbidity factors in severe COVID-19. However, the underlying pathomechanisms are largely undefined. Here, we sought to identify the potential underlying molecular mechanisms of SARS-CoV-2 mediated coagulopathy and thromboembolism. In this series, 30 hospitalized COVID-19 patients presenting elevated D-dimer with (severe cases that required intensive care) or without pneumonia (moderate cases) were included in the study. Patients with anticoagulant/ antiplatelet therapy or with a history of cardiovascular diseases were excluded. Phenotypic and molecular characterizations were carried out employing basic coagulation tests, flow cytometry-based multiplex assays, and ELISA. The findings revealed slightly higher prothrombin and activated partial thromboplastin times (aPTT) with normal platelet counts. Elevated levels of plasma P-selectin and CD40 ligand (CD40L), markers of platelet activation, were observed in the moderate COVID-19 cases which were significantly abolished with the progression of COVID-19 severity. Moreover, analysis of the coagulation pathways revealed comparable FIX, prothrombin, and anti-thrombin levels, and a significantly higher level of fibrinogen was observed in both the moderate and severe patients vs. control group. Interestingly, the levels of plasma tissue factor pathway inhibitor (TFPI) and FXIII, a regulator of stable thrombus formation, were significantly lower particularly in the severe COVID-19 cases. Moreover, a dysregulated fibrinolysis was indicated by elevated tissue plasminogen activator (tPA), plasminogen activator inhibitor (PAI), and D-dimer levels in COVID-19 cases. In summary, SARS-CoV-2 infection-mediated endothelial cell lining damage potentially enhances soluble P-selectin and CD40L levels inducing platelet activation. Furthermore, in severe COVID-19, a decreased level of TFPI possibly contributes to additional thrombin generation through activation of the TF pathway and provides positive feedback to platelet activation and thrombus formation. FXIII deficiency plays a key role in thrombus instability which most likely promotes thromboembolism in the severe COVID-19.

Coagulation dysfunction and thromboembolism emerge as strong comorbidity factors in severe COVID-19 patients. However, the underlying pathomechanisms are largely undefined. Here, we sought to identify the potential molecular mechanisms of SARS-CoV-2 mediated coagulopathy and thromboembolism. A broader investigation was conducted including hospitalized COVID-19 patients with (severe cases that required intensive care) or without pneumonia (moderate cases). Phenotypic and molecular characterizations were performed employing basic coagulation tests, flow cytometry-based multiplex assays, and ELISA. The investigations revealed induction of plasma P-selectin and CD40 ligand (sCD40L) in moderate COVID-19 cases which were significantly abolished with the progression of COVID-19 severity. Moreover, a profound reduction in plasma tissue factor pathway inhibitor (TFPI) and FXIII were identified particularly in the severe COVID-19. Further analysis revealed a profound induction of fibrinogen in both moderate and severe patients. Interestingly, an elevated plasminogen activator inhibitor-1 more prominently in moderate, and tissue plasminogen activator (tPA) particularly in severe COVID-19 cases were observed. Particularly, the levels of fibrinogen and tPA directly correlated with the severity of COVID-19. In summary, SARS-CoV-2 infection induces the levels of platelet activation markers soluble P-selectin and sCD40L in hospitalized COVID-19 patients. Furthermore, an attenuated level of TFPI indicates TF pathway activation and, acquired FXIII deficiency likely plays a key role in thrombus instability and promotes thromboembolism in severe cases. The progression of COVID-19 severity could be limited with anti-platelet in combination with recombinantTFPI treatment. Furthermore, thromboembolic events in severe COVID-19 patients could be minimized if treated with recombinantFXIII in combination with LMW heparin.

Cardiomyopathy is an irreparable loss and novel strategies are needed to induce resident cardiac progenitor cell (CPC) proliferation in situ to enhance the possibility of cardiac regeneration. Here we identify a potential role for glycogen synthase kinase-3β (GSK-3β), a critical regulator of cell proliferation and differentiation, in CPC proliferation that occurs after myocardial infarction (MI). Cardiomyocyte-specific conditional GSK-3β knockout (cKO) and littermate control mice were employed and challenged with MI. Though cardiac left ventricular chamber dimension (LVID) and contractile functions were comparable at two week post-MI, cKO mice displayed significantly preserved LV chamber and contractile function vs. control mice at four-weeks post-MI. Consistent with protective phenotypes, an increased percentage of c-kit positive cells (KPCs) were observed in the cKO hearts at four and six weeks post-MI which was accompanied by increased levels of cardiomyocyte proliferation. Further analysis revealed that the observed increased number of KPCs in the ischemic cKO hearts was mainly from a cardiac lineage as the majority of identified KPCs were negative for the hematopoietic marker, CD45. Mechanistically, cardiomyocyte-GSK-3β profoundly suppresses the expression of growth factors (GFs), including basic-FGF angiopoietin-2, erythropoietin, stem cell factor (SCF), PDGF-BB, G-CSF, and VEGF, post-hypoxia. In conclusion, our findings strongly suggest that loss of cardiomyocyte-GSK-3β promotes cardiomyocyte and resident CPC proliferation post-MI. The induction of cardiomyocytes and CPC proliferation in the ischemic cKO hearts is potentially regulated by autocrine and paracrine signaling governed by dysregulated growth factors post-MI. A strategy to inhibit cardiomyocyte GSK-3β could be helpful for promotion of in-situ cardiac regeneration post-MI injury.