Serum microRNA‑122 for assessment of acute liver injury in patients with extensive skeletal muscle damage

Background Serum level of microRNA-122 (miR-122) has been reported as a sensitive diagnostic biomarker for detecting liver injury, comparable to the aminotransferases. Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities are increased in other conditions, such as acute skeletal muscle injury (ASMI). We determined whether miR-122 is nonspecifically increased in patients suffering from ASMI. Methods We measured ALT, AST, creatine kinase (CK), and miR-122 in 3 groups: healthy controls (n = 24), patients with ASMI (total n = 29, 11 with recreational drug use and 18 without recreational drug use), and patients with acute liver injury (ALI; n = 14). Results Levels of ALT, AST, and CK increased 83%, 97%, and 100% for patients with ASMI and 100% for all 3 enzymes in ALI patients. In contrast, miR-122 increased in 34% of patients with ASMI (44.4% with recreational drug use and 18.2% without recreational drug use) and 100% of ALI patients. In 2 drug-induced liver injury cases, miR-122 increased about 12-24 hours before ALT and AST. Conclusion Recreational drug misuse is associated with both rhabdomyolysis and drug-induced liver injury (DILI). The traditional liver function markers AST and ALT were nonspecifically increased in the majority of patients with ASMI. miR-122 is only increased in patients at risk for DILI and demonstrates superior specificity for liver injury.