Convalescent COVID-19 patients are susceptible to endothelial dysfunction due to persistent immune activation

• Main Authors: Chioh, Florence Wen Jing, Fong, Siew-Wai, Young, Barnaby Edward, Wu, Kan Xing, Siau, Anthony, Krishnan, Shuba, Chan, Yi-Hao, Carissimo, Guillaume, Teo, Louis L. Y., Gao, Fei, Tan, Ru San, Zhong, Liang, Koh, Angela S., Tan, Seow-Yen, Tambyah, Paul A., Renia, Laurent, Ng, Lisa F. P., Lye, David C., Cheung, Christine
• Other Authors: Lee Kong Chian School of Medicine (LKCMedicine)
• Format: Article
• Language: English
• Published: 2021
• Subjects: Science::Medicine; COVID-19; Endothelial Cells
• Online Access: https://hdl.handle.net/10356/151759
• Institution: Nanyang Technological University

Numerous reports of vascular events after an initial recovery from COVID-19 form our impetus to investigate the impact of COVID-19 on vascular health of recovered patients. We found elevated levels of circulating endothelial cells (CECs), a biomarker of vascular injury, in COVID-19 convalescents compared to healthy controls. In particular, those with pre-existing conditions (e.g., hypertension, diabetes) had more pronounced endothelial activation hallmarks than non-COVID-19 patients with matched cardiovascular risk. Several proinflammatory and activated T lymphocyte-associated cytokines sustained from acute infection to recovery phase, which correlated positively with CEC measures, implicating cytokine-driven endothelial dysfunction. Notably, we found higher frequency of effector T cells in our COVID-19 convalescents compared to healthy controls. The activation markers detected on CECs mapped to counter receptors found primarily on cytotoxic CD8+ T cells, raising the possibility of cytotoxic effector cells targeting activated endothelial cells. Clinical trials in preventive therapy for post-COVID-19 vascular complications may be needed.