Serum microRNAs 122, 1275, 21, 222, and 181A are not differentially expressed in dogs with idiopathic or copper-associated chronic hepatitis.

Abstract

OBJECTIVE: To determine whether microRNAs 122, 1275, 21, 222, and 181A serve as noninvasive biomarkers of canine chronic hepatitis (CH); can distinguish between dogs with idiopathic CH (iCH) and copper-associated CH (CuCH); and correlate with serum ALT activity, grade of inflammation, fibrosis, and degree of copper accumulation. METHODS: From May 2019 through October 2023, dogs with CH, histologically characterized as either iCH or CuCH, and healthy control (HC) dogs without liver biopsies were enrolled in this prospective uncontrolled study. Serum samples were collected, and serum microRNAs were quantified by real-time quantitative PCR. Differences in gene fold expression between groups were calculated. Correlations between microRNA gene fold expression and serum ALT, hepatic copper quantification, grade of necroinflammatory activity, fibrosis, and histological copper score were assessed. RESULTS: A total of 18 dogs with iCH, 14 dogs with CuCH, and 42 HC dogs were enrolled. No differences between iCH and CuCH dogs were observed for any microRNA. Differences between HC and overall CH dogs were observed for microRNAs 122, 1275, and 21. Positive correlations with serum ALT activity between microRNAs 122 and 21 were observed. CONCLUSIONS: None of the studied microRNAs were able to differentiate iCH from CuCH and only correlated with ALT activity. Serum microRNAs 122, 1275, and 21 appear to be nonspecific makers of hepatocellular injury. CLINICAL RELEVANCE: Our results do not support the utility of these microRNAs as markers for distinguishing between iCH and CuCH in dogs.