Principal researcher Instituto Mexicano Del Seguro Social Mexico, Distrito Federal, Mexico
Background: The Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) disease known as COVID-19, which has presented in a mild, moderate or severe form, has sequelae that extend with persistent symptoms for weeks to months in referred patients, reducing their quality of life. Currently there is not effective treatment for long COVID. Abnormalities of the blood coagulation system have been detected in some patients, with persistent functional and structural abnormalities in the vascular endothelium, this suggest thrombotic status. We have previously demonstrated persistent abnormalities in endothelial colony-forming cells (ECFCs) from patients recovered from COVID-19.
Aims: Determine whether the ECFCs of patients with VTD after recovery from COVID-19 are dysfunctional.
Methods: Human mononuclear cells (MNCs) were obtained from peripheral blood from 25 recovered COVID-19 patients, 16 months after disease with schedule of 3 vaccines with a healthy lifestyle prior to infection and 10 healthy human volunteers (controls), matched by age. All were men (25−50 years). We assayed the frequency, morphological characteristics, proliferation and expression of molecules related to endothelial dysfunction in ECFCs. The study was approved by the Scientific and Ethical Committee of the IMSS (number IMSS-R-2020-785-167). Informed written consent was obtained from all subjects before enrollment.
Results: ECFCs were detected in average on day 10 of culture in recovered COVID-19 patients and day 21 in controls respectively. In recovered COVID-19 patients, ECFCs show abnormalities in size with elongations, large cytoplasm with prominent nuclei, similar to senescent state with no proliferative capacity when they were sub-cultured. The molecules CD-36, CD-62P CD-106, CD141, CD142 analyzed by flow cytometry are overexpressed.
Conclusion(s): We demonstrate for the first time that previously patients recovered from COVID-19 and vaccination schedule show VTD as a long-term sequel of long-COVID. ECFCs show morphological characteristics and overexpression of adhesion molecules, suggesting chronic dysfunction of the ECFCs.
