Post-mortem viral dynamics and tropism in COVID-19 patients in correlation with organ damage

Abstract

The persistence of SARS-CoV-2 after death of infected individuals is unclear. The aim of this study was to investigate the presence of SARS-CoV-2 RNA in different organs in correlation with tissue damage and post-mortem viral dynamics in COVID-19 deceased. Twenty-eight patients (17 males, 11 females; age 66-96 years; mean 82.9, median 82.5 years) diagnosed with COVID-19 were studied. Swabs were taken post-mortem during autopsy (N = 19) from the throat, both lungs, intestine, gallbladder, and brain or without autopsy (N = 9) only from the throat. Selective amplification of target nucleic acid from the samples was achieved by using primers for ORF1a/b non-structural region and the structural protein envelope E-gene of the virus. The results of 125 post-mortem and 47 ante-mortem swabs were presented as cycle threshold (Ct) values and categorized as strong, moderate, and weak. Viral RNA was detected more frequently in the lungs and throat than in the intestine. Blood, bile, and the brain were negative. Consecutive throat swabs were positive up to 128 h after death without significant increase of Ct values. All lungs showed diffuse alveolar damage, thrombosis, and infarction and less frequently bronchopneumonia irrespective of Ct values. In 30% the intestine revealed focal ischemic changes. Nucleocapsid protein of SARS-CoV-2 was detected by immunohistochemistry in bronchial and intestinal epithelium, bronchial glands, and pneumocytes. In conclusion, viral RNA is still present several days after death, most frequently in the respiratory tract and associated with severe and fatal organ damage. Potential infectivity cannot be ruled out post-mortem.

Pathophysiological mechanisms of liver injury in COVID‐19

“…[166][167][168] Recently, viral nucleocapsid protein could be demonstrated within enterocytes by immunohistochemistry. 24 The Human Protein Atlas database further corroborates these observations, with intestinal cells exhibiting the highest pattern of ACE2 expression across the whole human cell type repertoire (data available at https://www.prote inatl as.org/ENSG0 00001 30234 -ACE2/ tissue). Moreover, human intestinal organoids have been shown to be permissive to SARS-CoV and SARS-CoV-2 infection.…”

“…24,49 These discrepancies might rely on the fact that the positive-tested bile sample has been obtained during surgical resolution of bile duct obstruction, 76 whereas the negatively tested bile was obtained from 48h post-mortem autopsies. 24,49 Tight junctions allow cholangiocytes to act as a protective barrier The negative regulation of these hepatobiliary transporters may impair bile acid sensing/signalling by cholangiocytes and bicarbonate secretion, eventually contributing to biliary changes observed in COVID-19 infection. 49 Furthermore, cholangiocytes infected with SARS-CoV-2 virus upregulated inflammatory pathways, depicting the induction of a reactive cholangiocyte phenotype.…”

“…Nevertheless, the pro-inflammatory milieu generated by direct or detection of viral protein by immunohistochemistry. 24,86 However, a histopathologic assessment of ACE2 tissue distribution showed no staining in Kupffer cells and other hepatic immune cells, 56 although Kupffer cell proliferation is typically observed in livers of COVID-19 diseased. 40,49 The recent COVID-19 pandemic further prompted more in-detail investigations on ACE2 expression and de novo single-cell RNAseq analyses, 54 as also in silico evaluations of RNAseq databases 87,88 proved that Kupffer cells do not express ACE2.…”

“…RNA and viable virions have been identified in stool samples of infected patients and post-mortem. 24,[159][160][161][162] Hepatic and gastrointestinal manifestations appear more frequently in severe forms of COVID-19 infections. [3][4][5][163][164][165] Interestingly, a recent study by Jin and colleagues showed that individuals with pre-existing liver diseases are more susceptible to develop an intestinal phenotype upon SARS-CoV-2 infection.…”

“…On the other hand, COVID-19 with fatal outcome seems to be associated with severe damage of lung tissue, whereas the intestines are only mildly altered, most commonly by focal ischaemic changes in the intestinal mucosa. 24 Whether biliary tropism and requirement of bile/bile acids for viral attachment and entry into cholangiocytes and enterocytes 171,172 also play a role for SARS-CoV-2 remains to be determined. Given the functional and physiological similarities between bile ducts and ducts of the exocrine pancreas, and the observations concerning a potential pancreatic involvement in COVID-19 infection, 49,173,174 the research of a common mechanism allowing infection of the two tissues might help in uncovering further determinants of SARS-CoV-2 tropism.…”