Patients with COVID-19 may be at risk for liver injury, but mechanisms of damage remain unclear, according to investigators.
Proposed mechanisms include direct virus-induced effects, immune-induced damage due to excessive inflammatory responses, and drug-induced injury, reported lead author Ling Xu of Huazhong University of Science and Technology, Wuhan, China, and colleagues.
“From a clinical perspective, in addition to actively dealing with the primary disease caused by coronavirus infection, attention should also be paid to monitor the occurrence of liver injury, and to the application of drugs which may induce liver damage,” the investigators wrote in Liver International. “Patients with liver damage are advised to be treated with drugs that could both protect liver functions and inhibit inflammatory responses, such as ammonium glycyrrhizinate, which may, in turn, accelerate the process of disease recovery.”
The review of liver injury associated with major pathogenic coronaviruses included severe acute respiratory syndrome coronavirus (SARS-CoV), the Middle East respiratory syndrome coronavirus (MERS-CoV), and the newly emergent SARS-CoV-2, which causes COVID-19.
In cases of COVID-19, reported incidence of liver injury ranges from 15% to 53%, based on elevations of alanine transaminase (ALT) and aspartate aminotransferase (AST), along with slightly elevated bilirubin levels. In severe cases, albumin decreases have also been documented.
Liver injury appears to be significantly more common among those with severe infection. In one cohort of 82 patients who died from COVID-19, the incidence of liver injury was 78%, while another study of 36 nonsurvivors reported a rate of 58%.
According to the investigators, both bile duct epithelial cells and liver cells express angiotensin converting enzyme II (ACE2), which is an entry receptor for SARS-CoV-2; however, expression of ACE2 in bile duct cells is “much higher” than in liver cells, and comparable with alveolar type 2 cells in the lungs.
“Bile duct epithelial cells are known to play important roles in liver regeneration and immune response,” the investigators noted.
Beyond direct- and immune-induced effects of COVID-19, postmortem findings suggest that drug-induced liver injury may also be a possibility, with a number of theoretical culprits, including antibiotics, steroids, and antivirals. Although the investigators emphasized that data are insufficient to pinpoint an exact agent, they highlighted a recent preprint study, which reported a significantly higher rate of lopinavir/ritonavir administration among patients with abnormal liver function, compared with those who had normal liver function (56.1% vs. 25%; P = .009).
“Drug-induced liver injury during the treatment of coronavirus infection should not be ignored and needs to be carefully investigated,” the investigators concluded.
Fundamental Research Funds for the Central Universities supported the work. The investigators reported no conflicts of interest.
SOURCE: Xu L et al. Liver Int. 2020 Mar 14.