Association between COVID-19 and chronic liver disease: Mechanism, diagnosis, damage, and treatment

Table 1 Summary of the mechanism, diagnosis, damage, and treatment of coronavirus disease 2019 in chronic liver disease patients

Feature	Conclusion of each part
Mechanism	SARS-CoV-2 can bind to the host ACE2 receptor, allowing the virus to enter cells and actively replicate in the liver. Severe disease outcomes depend on the high affinity of the virus to ACE2. In addition, SARS-CoV-2 infection can lead to severe host hyperimmunity in the lungs, triggering a life-threatening cytokine storm[21,22], a systemic inflammatory response syndrome driven by viral infection. This leads to tissue damage and multiple organ damage or failure. In addition, symptoms due to COVID-19 complications are underlying pathological mechanisms of extensive liver injury
Diagnosis	Liver biochemical abnormalities are common in COVID-19-related CLD patients. The main manifestations of patients with COVID-19-related CLDs are moderately elevated serum transaminase activity and elevated LDH levels. The severity of CLD during the COVID-19 course can be effectively judged by detecting serum transaminase, LDH, bilirubin levels, and albumin concentrations
Damage	Invasion of SARS-CoV-2 may lead to significant systemic disease; some can even develop severe lung disease, leading to respiratory compromise, which in turn may progress to multiple organ failure, coagulopathy, and death. Typically, COVID-19 patients are more vulnerable and susceptible to underlying metabolic diseases. In addition, SARS-CoV-2 can cause CLD by direct cytopathies, immune-mediated, hypoxia/ischemia, and microvascular thrombosis
Treatment	Immunosuppression therapy is meaningful for both COVID-19 and CLD. Therefore, immunosuppressive drugs should be evaluated during the co-occurrence of both disorders
	Common immunosuppressive drugs include calcineurin inhibitors and mTOR inhibitors. Medication side effects need to be considered during treatment, including increasing susceptibility to SARS-CoV-2 infection and secondary bacterial or fungal infection and prolonged viral clearance. In addition, currently prescribed drugs for COVID-19 are all metabolized in the liver, and these antiviral drugs may lead to abnormal liver function. Therefore, it is necessary to balance the management of immunosuppressive therapy and drug interactions in patients with CLD infected with COVID-19 and minimize the use and dosage of immunosuppressants to reduce the impact of liver damage

SARS-CoV-2: Severe acute respiratory syndrome coronavirus 2; ACE2: Angiotensin-converting enzyme 2; COVID-19: Coronavirus disease 2019; CLD: Chronic liver disease; LDH: Lactate dehydrogenase.