Fig. 1

Evaluation of ACE2 protein and endothelial cells in cerebral thrombi. A ACE2 expression in thrombi of COVID-19 patients and controls. Representative images of a thrombus of a COVID-19 and a control patient with ACE2 immunohistochemical staining (staining in brown, the inset displays a magnification of the dashed box area and arrowheads highlight some positive cells). Histogram showing the ACE2⁺ area as percentage of the total thrombus area, *p = 0.04, Mann–Whitney. B. Endothelial cells (CD34⁺ area) in cerebral thrombi of COVID-19 patients and controls. Representative images of a thrombus of a COVID-19 and control patient with CD34 immunohistochemical staining (in blue, arrowheads highlight CD34⁺ cells). Histogram of the CD34⁺ area as percentage of the total thrombus area; p = 0.86, Mann–Whitney. C. Characterization of ACE2-expressing cells. Representative images of double-immunohistochemistry with ACE2 (in either purple or blue) and either CD34 (in blue), CD68 (in brown), CD3 (in blue), or MPO (in blue). The inset displays a magnification of the dashed box area and arrowheads highlight double positive cells. A donut graph showing the percentage of cells expressing ACE2 out of the total of ACE2⁺ cells. The graphs represent the median and IQR, each dot in the scatter plot represents the thrombus of one patient (n = 7 COVID-19 patients and n = 23 controls); scale bar A- C, 50 µm