ABSTRACT
BACKGROUND. COVID-19 is a prothrombotic disease, characterized by endotheliopathy, hypercoagulability, and thromboembolic complications. We hypothesized that the pathogenesis of thromboembolism associated with COVID-19 might differ from thromboembolism in patients without COVID-19. In this study, we sought to evaluate the proteomic signatures of plasma from patients with venous thromboembolism with and without COVID-19. METHODS. Between December 17, 2020 and February 25, 2021 blood was collected from 48 hospitalized patients. Of these 24 had a confirmed diagnosis of COVID-19 infection (COVID+) and radiologic confirmation of arterial or venous thromboembolism (TE+);17 had COVID-19 infection with absence of arterial thrombosis clinically and absence of venous thromboembolism on lower extremity Doppler ultrasound or chest CT angiography (COVID+/TE-), while 7 were arterial or venous thromboembolism in the absence of COVID-19 (COVID-/TE+). Blood was collected in sodium citrate tubes and centrifuged at 4000 rpm for 20 minutes, with resulting plasma supernatant used for protein profiling performed at Eve Technologies (Calgary, Alberta, Canada). Institutional Review Board approval was obtained for this study. Statistical analysis was performed using GraphPad Prism (v9.1, GraphPad Software, San Diego, CA) and R (v4, R Core Team). P values <0.05 were considered statistically significant. A heatmap was generated using Heatmapper (heatmapper.ca) to represent the concentrations of proteins. RESULTS. The median age was 63 years;overall 25 (52%) were men (13 [54%] among COVID+/TE+, 11 [65%] among COVID+/TE-, and 1 [14%] among COVID-/TE+). In COVID-19 patients who developed thromboembolic events, several proteins associated with inflammation, complement activation, and hemostasis were present at higher levels than in non-COVID-19 patients who developed thromboembolic events (Fig. 1). These included complement factors C2 and C5a, pentraxin-3 (PTX-3), lipocalin-2 (LCN2), resistin (RETN), platelet endothelial cell adhesion molecule-1 (Pecam1), serum amyloid A (SAA), and tissue factor (TF). The heatmap indicates relative protein levels detected in each subject (columns) for proteins (rows) that had statistically significant differences between groups (Fig. 2). Heatmap revealed relatively lower levels of all proteins in patients with thromboembolism without COVID-19 and relatively higher levels of proteins in patients with COVID-19, and especially in ICU patients with COVID-19 and thromboembolism. CONCLUSIONS. Thromboembolic complications in patients with COVID-19 are associated with increased levels of various proteins involved in complement activation and immunothrombotic cascades, compared to thrombotic events in the absence of COVID-19. Activation of the classical complement pathway as evidenced by a relative increase in complement factor C2 may lead to increased TF activation, reflecting more substantial endothelial damage in COVID-19 patients. Higher levels of Pecam1, SAA, LCN2, and RETN all point to increased endotheliopathy, inflammation, and tissue damage in COVID-19 compared to non-COVID-19 thrombosis. These findings may offer insights into novel therapeutic strategies to treat immunothrombotic complications of COVID-19. [Formula presented] Disclosures: No relevant conflicts of interest to declare.
ABSTRACT
Objective: Early reports suggest an increased risk of ischemic stroke during COVID-19 infection. We aimed to identify patients with COVID-19 and ischemic stroke and explore markers of endotheliopathy, inflammation, and hypercoagulability. Background: Novel coronavirus-19 disease (COVID-19) is associated with a diverse array of neurologic complications, including ischemic stroke. Suspected mechanisms include hypercoagulability and endothelial injury, although evidence is sparse in stroke patients. Design/Methods: This was a retrospective, observational cohort study of patients with acute ischemic stroke and COVID-19 (n=21) compared to non-COVID-19 acute ischemic stroke patients (n=11). Timing of stroke onset during COVID-19 course, acute phase reactant levels, cytokine levels, endothelial activation, and hypercoagulability were evaluated with respect to stroke onset and etiology. Results: Twenty-one ischemic stroke patients were diagnosed with COVID-19 during the study period. Both groups had a similar age and burden of vascular risk factors. COVID-19 patients had significantly higher levels of endothelial activation around the time of stroke when compared to controls. The mean Factor VIII level was 332% of normal in the COVID-19 group and 49% in the control group, while von Willebrand Factor antigen and activity were 330% and 285% in the COVID-19 group and 213% and 152% in the control group, respectively. Cytokine storming and a strong inflammatory responses are defining features of severe COVID-19. We demonstrated a temporal correlation between stroke onset and the peak of acute phase reactants. Elevated cytokine levels, IL-6 and soluble IL-2 receptor levels in particular, were significantly associated with embolic stroke of undetermined source (ESUS) in COVID-19 patients when compared with other etiologies. Conclusions: We provide emerging evidence that endotheliopathy and the systemic inflammatory response in patients with vascular risk factors and COVID-19 is associated with ischemic stroke. Further research is needed. Understanding the mechanism of stroke in COVID- 19 patients will be critical in providing primary stroke prevention and treatment.