Figure: Pathology of endothelial ce

Figure: Pathology of endothelial cell dysfunction in COVID-19(A, B) Electron microscopy of kidney tissue shows viral inclusion bodies in a peritubular space and viral particlesin endothelial cells of the glomerular capillary loops. Aggregates of viral particles (arrow) appear with densecircular surface and lucid centre. The asterisk in panel B marks peritubular space consistent with capillarycontaining viral particles. The inset in panel B shows the glomerular basement membrane with endothelial celland a viral particle (arrow; about 150 nm in diameter). (C) Small bowel resection specimen of patient 3,stained with haematoxylin and eosin. Arrows point to dominant mononuclear cell infiltrates within the intimaalong the lumen of many vessels. The inset of panel C shows an immunohistochemical staining of caspase 3 insmall bowel specimens from serial section of tissue described in panel D. Staining patterns were consistent withapoptosis of endothelial cells and mononuclear cells observed in the haematoxylin-eosin-stained sections,indicating that apoptosis is induced in a substantial proportion of these cells. (D) Post-mortem lung specimenstained with haematoxylin and eosin showed thickened lung septa, including a large arterial vessel withmononuclear and neutrophilic infiltration (arrow in upper inset). The lower inset shows animmunohistochemical staining of caspase 3 on the same lung specimen; these staining patterns wereconsistent with apoptosis of endothelial cells and mononuclear cells observed in the haematoxylin-eosinstainedsections. COVID-19=coronavirus disease 2019.