COVID-19 and the Liver: A 2021 Update

Catherine W. Spearman; Alessio Aghemo; Luca Valenti; Mark W. Sonderup

Disclosures

Liver International. 2021;41(9):1988-1998. 

In This Article

Liver Histopathology in COVID-19

Few liver histology-based COVID-19 case series have been published. Histopathological changes ranging from moderate micro-vesicular steatosis with mild, mixed lobular and portal inflammation to focal necrosis have been described.[42–44] Sinusoidal dilatation is noted, but no bile duct injury has been documented.[45] SARS-CoV-2 RNA has been isolated from liver tissue through RT-PCR, and the virus has been detected on electron microscopy.[44,46] In a USA post-mortem series, SARS-CoV-2 viral RNA was detectable by PCR in 55% of liver samples tested.[43] An Italian autopsy series of 48 post-mortem wedge liver biopsies revealed focal portal and lobular lymphocytic infiltrates and also diffuse intra-hepatic vascular abnormalities with partial or complete acute portal vein and sinusoidal thrombosis.[47] It is uncertain as to whether this represents a direct effect of SARS CoV-2 infection or is consequent to overwhelming systemic complications of COVID-19. Proteomic assessment of post-mortem liver tissue from 19 patients who died from COVID-19 showed upgregulated profibrotic pathways, dysregulated fatty acid oxidation, oxidative phosphorylation and immune activation, but little evidence of active viral replication.[23,48] This proteomic dysregulation of liver proteins was associated with multiorgan dysfunction, hepatic steatosis and coagulative hepatocyte necrosis.[23,48]

A recent systemic review and meta-analysis of liver histopathological findings determined the following pooled prevalence estimates: hepatic steatosis 55.1% [95% CI: 46.2–63.8], congestion of hepatic sinuses 34.7% [95% CI: 7.9–68.4], vascular thrombosis 29.4% [95% CI: 0.4–87.2], fibrosis 20.5% [95% CI: 0.6–57.9], Kupffer cell hyperplasia 13.5% [95% CI: 0.6–54.3], portal inflammation 13.2% [95% CI: 0.1–48.8] and lobular inflammation 11.6% [95% CI: 0.3–35.7].[50]

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