Fig. 2

Circulating biomarkers of endothelial function in individuals with ME/CFS and long COVID compared with matched sedentary healthy controls. Representative box plot analysis of eight endothelial proteins showing statistically significant differences in plasma levels of ET-1, TSP-1, VCAM-1, ICAM-1, serpin E1 (PAI-1), E-selectin, adiponectin, and nitric oxide (NOx) at baseline from ME/CFS patients, individuals with long COVID, and matched sedentary healthy controls, as described in the Methods section (panel A-H). Each dot represents a single participant in each group. Values are expressed as mean ± standard error of the mean (SEM) of duplicated assays and are representative of two independent experiments. The box extends from the 25th to 75th percentiles, the line represents the mean, and the whiskers indicate the range of minimum and maximum values within SEM. P-values were calculated using the non-parametric Kruskal-Wallis test with Dunn’s post-hoc multiple comparison test. Significance level was set at *p < 0.05, **p < 0.01, and ***p < 0.001