Endothelial dysfunction in post-COVID-19 syndrome: a question of circulating regenerative cell viability?

Background: The distressing impacts of COVID-19 and long-COVID syndrome underscore the profound extent to which the virus has disrupted societies on a global scale. COVID-19 is associated with endothelial dysfunction, which can lead to multi-organ injury. While circulating progenitor cells (CPC) have the potential to regenerate the endothelium and circulating endothelial cells (CEC) dislodge from damaged vessel walls, they are considered valid cell-based biomarkers to assess the health status of the vascular endothelium. The apoptosis of CPC/CEC shows the functionality of these cells.
Methods: Blood samples were taken from 18 months post-COVID-19 patients (n = 12) and healthy subjects (n = 4) with no COVID-19 history. After cell isolation and cell count were performed, a comparison between the two groups was made to reveal potential significant differences.
Results: The analysis of total, viable and necrotic CPC and CEC count revealed no statistically significant differences between patients and control subjects. Notably, significant elevated levels of apoptotic CECs (p = 0.03) were observed within the control group. However, no significant difference was found regarding apoptotic CPCs between the two groups.
Conclusions: The comprehensive analysis of CPCs and CECs between post-COVID-19 patients and healthy subjects provides valuable insights into the aftermath of COVID-19. While no significant differences were observed in total, viable and necrotic CPC and CEC count, the elevated apoptotic CECs levels within the control group suggests a disruption of apoptotic mechanisms in post-COVID-19 patients. Further research is needed to enhance the under-standing of the long-term consequences of COVID-19.