Exosomal microRNAs Drive Thrombosis in COVID-19

Thrombotic and thromboembolic complications have been shown to play a critical role in the clinical outcome of COVID-19. Emerging evidence has shown that exosomal miRNAs are functionally involved in a number of physiologic and pathologic processes. However, neither exosomes nor miRNAs have been hitherto investigated in COVID-19. To test the hypothesis that exosomal miRNAs are a key determinant of thrombosis in COVID-19, we enrolled patients positive for COVID-19. Circulating exosomes were isolated from equal amounts of serum and levels of exosomal miRNAs were quantified. We divided our population in two groups based on the serum level of D-dimer on admission. Strikingly, we found that exosomal miR-424 was significantly upregulated whereas exosomal miR-103a, miR-145, and miR-885 were significantly downregulated in patients in the high D-dimer group compared to patients in the low D-Dimer group (p<0.0001).