Pathophysiology and molecular mechanisms of liver injury in severe forms of COVID-19: An integrative review

BACKGROUND AND AIMS: SARS-CoV-2 has primary pulmonary impairment, but other organs such as the liver can also be affected. This implies a worsening of patient's prognosis and an increase in morbidity and mortality. The metabolic pathways and molecular factors involved in the genesis of this injury are still unknown. Therefore, we aimed to carry out an integrative review about the pathophysiology and possible molecular mechanisms of liver injury by COVID-19. METHODS: We carried out an integrative literature review in the following databases: PubMed, Scopus, and Embase from December 2020 to March 2021 using the following descriptors: # 1 “COVID-19” (MeSH) AND / OR # 2 “Liver injury” (MeSH) AND / OR # 3 “Pathophysiology” (MesH). RESULTS: The data were extracted and divided into two main themes, for heuristic purposes: “Hepatotropism and SARS-CoV-2”, and “Pathophysiological hypotheses for liver injury associated with SARS-CoV-2”. CONCLUSIONS: The virus seems to promote liver damage through five mechanisms: direct injury, humoral and cellular inflammatory response, hypoxemia caused by a decrease in the effective circulating volume, reinfection through the portal system, and use of drugs in the treatment. The literature also points out that the expression of the angiotensin-converting enzyme II and transmembrane serine protease 2 receptors is expressive in cholangiocyte and is present in hepatocytes, which is a risk factor for the virus to enter these cells. Finally, patients with previous liver disease appear to be more susceptible to liver injury by COVID-19.