COVID-19 is frequently associated with a coagulopathy with severe consequences. The mechanisms leading to a pro-coagulant state in these patients is multifactorial, including tissue destruction and inflammatory mechanisms. Based on the analysis of publicly available interactomes, we propose that SARS-CoV-2 infection causes a deficiency in C1 esterase inhibitor (C1-INH), a pathogen-specific mechanism that may help explain the pro-coagulant state in COVID-19 patients.

COVID-19 induces coagulopathy at the base of SIC (sepsis-induced coagulopathy) and it is an important cause of death in the patients. Cytokine storm causes imbalance in coagulation and fibrinolytic system. A combination of hypercoagulability state, decrease or inhibition of fibrinolytic and endothelialopathy causes thromboembolic events. Underlined disease with a high rate of mortality in COVID-19 like diabetes, hypertension and some conditions like aging and obesity are the main disorders with hemostatic disturbance and increase of coagulopathy. Therefore, it seems that the combination of COVID-19 infection and these risk factors increase the risk of thromboembolic all together.

Background: Uncontrolled hemorrhage is a major preventable cause of death in patients with trauma. However, the majority of large animal models of hemorrhage have utilized controlled hemorrhage rather than uncontrolled hemorrhage to investigate the impact of immunopathy and coagulopathy on multi-organ failure (MOF) and mortality. This study evaluates these alterations in a severe porcine-controlled and uncontrolled hemorrhagic shock (HS) model. Methods: Anesthetized female swine underwent controlled hemorrhage (22 ml/kg) and uncontrolled hemorrhage by partial splenic resection followed with or without lactated Ringer solution (LR) or Voluven® resuscitation. Blood chemistry, physiologic variables, systemic and tissue levels of complement proteins and cytokines, coagulation parameters, organ function, and damage were recorded and assessed. Results: HS resulted in systemic and local complement activation, cytokine release, metabolic acidosis, hyperkalemia, MOF, and no animal survival. Resuscitation with LR and Voluven® after HS improved hemodynamic parameters (MAP and SI), metabolic acidosis, hyperkalemia, and survival but resulted in increased complement activation and worse coagulopathy. Compared with the LR group, the HS animal treated with Voluven® had worse dilutional anemia, coagulopathy, renal and hepatic dysfunction, increased myocardial complement activation and renal damage, and decreased survival rate. Conclusions: Hemorrhagic shock triggers early immunopathy and coagulopathy that appear associated with MOF and death. This study indicates that immunopathy and coagulopathy are therapeutic targets that may be addressed with a high-impact adjunctive treatment to conventional resuscitation.

Since the first description of COVID-19 infection, among clinical manifestations of the disease including fever, dispnea, cough, fatigue, it was observed a high incidence of thromboembolic events potentially evolving towars ARDS and COVID-associated-coagulopathy (CAC).The hypercoagulation state is based on an interaction between thrombosis and inflammation. The so-called CAC represents a key aspect in the genesis of organ damage from SARS-CoV-2. The prothrombotic status in COVID-19 disease can be explained by the increase of coagulation levels of D-dimer, lymphocytes, fibrinogen, IL-6 and prothrombin time. Several mechanisms have been hypothesized to explain this hypercoagulable process such as inflammatory cytokine storm, platelet activation, endothelial dysfunction and stasis for a long time. The purpose of this narrative review is to provide an overview of the current knowledge on the pathogenic mechanisms of coagulopathy that may characterize COVID-19 infection and inform on new areas of research. New vascular therapeutic strategies are also reviewed.

COVID-19-associated coagulopathy (CAC) and ICU admissions were recognized as critical health issues that contributed to the morbidity and mortality in SARS-CoV-2-infected patients. Here, we analyzed publicly available data from the Yale IMPACT cohort to address immunological misfiring and sex differences in early COVID-19 ICU patients by taking various biological variables into account that were not considered. In 2020, SARS-CoV-2 was considered far more pathogenic and lethal than other circulating respiratory viruses, and it is thus surprising that published studies failed to confirm whether all patients were indeed SARS-CoV-2+ at least by one method, thereby confounding many findings/conclusions. Several key findings were further missed or misinterpreted due to lack of consideration of several important biological variables such as days from symptoms onset (DFSO), risk factors, including obesity, and treatments that influence the immunological measures evaluated. The immune profile in the early phase of infection will differ vastly from mid-to-late phases of infection, which likely coincides with recovery or is the tipping point for progression to severe illness, and thus grouping patients from different phases/DFSO into one single group is not the right approach. Taken together, our analysis shows that interferon responses were dampened and none of the early treatments were effective in reducing levels of IL6, and that obese patients exhibited highest mortality and worst clinical scores. The opportunity to understand the contribution of biological sex, risk factors, and early treatments with respect to COVID-19-related ICU admission and progression to morbidity and mortality was missed.

COVID-19 has rapidly spread worldwide since December 2019. During the pandemic, SARS-CoV-2 repeatedly mutated from Alpha to Omicron. The severity and mortality are related to age, sex, and underlying diseases (respiratory, cerebrovascular, cardiovascular, metabolic, cancer, and immune diseases). We retrospectively studied 44 hospitalized stroke patients infected with the SARS-CoV-2 Omicron variant. The mortality rate of hospitalized stroke patients with COVID-19 was 6 (13.6%). The cause of death was coagulopathy in 3 cases of ischemic stroke. High modified Rankin Scale score（mRS）of stroke patient was correlated with severity of COVID-19. The timing of vaccination is inversely correlated with COVID-19 severity. In conclusion, stroke patients with COVID-19 have high mortality rates attributed to coagulopathy. Stroke patients with high mRS scores are more likely to develop severe COVID-19. In high mRS scores, therapy for severe COVID-19 should be administered.

Coronavirus 19 disease (COVID-19) may be complicated by thrombotic events, particularly venous thromboembolism (VTE), which have been reported both in critically ill hospitalized patients and in individuals with mild symptoms. It is known that the chronic use of oral contraceptive pills (OCPs) is associated with higher risk of VTE. To date, there are only few reports concerning the association of OCPs and VTE/pulmonary embolism (PE) in COVID-19 patients. Given that during the convalescent phase of disease, a state of endothelial dysfunction, hypercoagulability and a low-grade inflammation may be persistent, the occurrence of thromboembolic events following acute COVID-19 infection may be not surprising. Herein, we report a case of high-risk PE detected in a post-COVID-19 young woman under hormonal contraception, which required thrombolytic treatment. A number of prothrombotic phenomena, such as overweight, hormonal contraceptive therapy, recent COVID-19 infection and prolonged immobilization, might have synergically contributed to the development of a sublethal thromboembolic event.

COVID-19, the infectious disease caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), is frequently associated with pulmonary thrombotic events, especially in hospitalised patients. Severe SARS-CoV-2 infection is characterized by a proinflammatory state and an associated disbalance in hemostasis. Immune pathology analysis supports the inflammatory nature of pulmonary arterial thrombi composed by white blood cells, especially neutrophils, CD3+ and CD20+ lymphocytes, fibrin, red blood cells and platelets. Immune cells, cytokines, chemokines and the complement system are key drivers of immunothrombosis, as they induce the damage of endothelial cells and initiate pro-inflammatory and pro-coagulant positive feedback loops. Neutrophil extracellular traps induced by COVID-19-associated “cytokine storm”, platelets, red blood cells, and coagulation pathways close the inflammation-endotheliopathy-thrombosis axis, contributing to SARS-CoV-2 associated pulmonary thrombotic events. The hypothesis of immunothrombosis is also supported by the minor role of venous thromboembolism, chest CT imaging data showing peripheral blood clots associated with inflammatory lesions and the high incidence of thrombotic events despite routine thromboprophylaxis. Understanding the complex mechanisms behind COVID-19-induced pulmonary thrombosis will lead to future combination therapies for hospitalised patients with severe disease, that would target the crossroads of inflammatory and coagulation pathways.

Neutrophils are the principal trouper of innate immune system. Activated neutrophils undergo a noble cell death termed NETosis and release a mesh-like structure called neutrophil extracellular traps (NETs) as a part of their defensive strategy against microbial pathogen attack. This web-like architecture includes a DNA backbone embedded with antimicrobial proteins like myeloperoxidase (MPO), neutrophil elastase (NE), histones etc. and deploys in the entrapment and clearance of encountered pathogens. Thus NETs play an inevitable beneficial role in the host's protection. However, recent accumulated evidence shows that dysregulated and enhanced NET formation has various pathological aspects including promotion of sepsis, pulmonary, cardiovascular, hepatic, nephrological, thrombotic, autoimmune, pregnancy, cancer diseases etc. and the list is increasing gradually. In this review, we summarize NETs mediated pathophysiology of different diseases, focus on some updated potential therapeutic approaches against NETs and share our future perspectives.

Although most cases of COVID-19 are paucisymptomatic, severe disease is characterized by immune dysregulation, with a decreased type I interferon response, increased inflammatory indicators, surging IL-6, IL-10 and TNFα suggestive of cytokine storm, progressive lymphopenia, and abnormal blood clotting. Factors determining susceptibility to severe disease are poorly understood, although mortality correlates with increasing age and co-morbidities including diabetes and cardiovascular disease (CVD). Pyridoxal 5'-phosphate (PLP) tends to be insufficient in populations particularly vulnerable to COVID-19, including the elderly, the institutionalized, and people with diabetes and CVD, and PLP becomes further depleted during infection and inflammation. In turn, low PLP results in immune imbalance, as PLP is an essential cofactor in pathways regulating cytokine production, in particular type I interferons and IL-6, and in lymphocyte trafficking and endothelial integrity. Furthermore, normalizing PLP levels attenuates abnormalities in platelet aggregation and clot formation. Finally, PLP insufficiency induces excess secretion of renin and angiotensin, and hypertension. In inflammatory disease, pharmacological doses of PLP decrease circulating TNFα, IL-6 and D-dimer, and animal studies demonstrate that supplemental PLP shortens the duration and severity of viral pneumonia. Severe COVID-19 manifests as an imbalance in the immune response and the clotting system. Pharmacological PLP supplementation may therefore mitigate COVID-19 symptoms by alleviating both the immune suppression underlying viral spread and the pathological hypersecretion of inflammatory cytokines, as well as directly bolstering endothelial integrity and preventing hypercoagulability.

The article describes the rational for inhibition of the angiotensin-converting enzyme 2 (ACE2) pathways as specific targets in patients infected by SARS-CoV-2 in order to prevent the establishment of positive feedback loops triggered by COVID-19 in some predisposed subjects. Making use of a large quantity of published reports in which human/rodent ACE2 pathway inhibitors were administered in vivo, it is hypothesized a possible therapeutic pharmacological intervention through an inhibition strategy of the zinc metalloprotease ACE2 and its downstream pathway for SARS-CoV-2 patients. Of even more interest, metal (zinc) chelators and renin inhibitors (both FDA approved drugs) may also work alone or in combination in inhibiting the positive feedback loops, initially triggered by COVID-19 and subsequently sustained by hypoxia independently on viral trigger, when both arms of renin-angiotensin system (ACE2 and ACE) are upregulated, leading to critical, advanced and untreatable stages of the disease.