Hepatic angiotensin-converting enzyme 2 expression in metabolic dysfunction-associated steatotic liver disease and in patients with fatal COVID-19

Figure 4 Angiotensin-converting enzyme 2 protein levels are increased in post-mortem livers of patients who died with severe coronavirus disease 2019. A: Computational quantification of hepatic angiotensin-converting enzyme 2 (ACE2) protein immunostaining in post-mortem tissue sections from the coronavirus disease-19 ‘Exploration of Critical Aspects of Pathogenesis’ (ICECAP) patient cohort with and without histopathological evidence of liver injury (LI) (ICECAP + LI and ICECAP no LI), including steatosis and/or fibrosis. Groups were compared by one-way ANOVA with Bonferroni’s post-hoc test (Normal vs ICECAP + LI: P < 0.05, comparison of Normal vs ICECAP no LI not statistically significant); B: Correlation between histological fibrosis (picrosirius red-positive area) and hepatic ACE2 protein levels (ACE2-positive area) assessed by Spearman’s correlation coefficient: r_s = 0.29, P = 0.39, not statistically significant; C: Correlation between lipid droplet content (lipid droplet positive-area) and hepatic ACE2 protein levels (ACE2-positive area) assessed by Spearman’s correlation coefficient: r_s = 0.04, P = 0.89, not statistically significant; D: Representative image showing granular ACE2 immunostaining pattern (arrowhead) in the cytoplasm of hepatocytes in pericentral areas of the liver lobule (central vein) in a steatotic post-mortem liver. Scale bar: 50 µm; E: Representative image showing a bile duct is shown with strong and specific staining localised to the apical membrane of cholangiocytes (arrowhead). Scale bar: 20 µm. ACE2: Angiotensin-converting enzyme 2; LI: Liver injury. CV: Central vein; BD: Bile duct.