Hepatocyte-derived canine familiaris-microRNAs as serum biomarkers of hepatic steatosis or fibrosis as implicated in the pathogenesis of canine cholecystolithiasis

Abstract

Background: Hepatic cholesterol accumulation in small breed dogs is a leading risk factor for hepatic fatty changes, gallbladder hypomotility, and cholelith development, which, if not discovered early, could lead to life-threatening choledocholithiasis and acute pancreatitis.

Objective: This study proposed to assess the use of hepatocyte-derived canine familiaris (cfa)-microRNAs (miRNA-122, -34a, and -21) as new diagnostic serum biomarkers of liver steatosis or fibrosis, for which both processes have been implicated in canine cholecystolithiasis.

Methods: Forty client-owned dogs diagnosed with cholecystolithiasis and hepatic steatosis (C+HS) or fibrosis (C+HF) based on ultrasonographic, biochemical, and histopathologic findings, and 20 healthy dogs used as controls were included in the study. Serum cfa-miRNA expression was determined using a real-time polymerase chain reaction assay.

Results: Serum cfa-miRNA-122 and -34a expression was significantly upregulated in the C+HS (P < .001) and C+HF (P < .01) groups compared with the control group and showed a positive correlation with alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin (TBIL), alkaline phosphatase (ALP), γ-glutamyl transferase (GGT), total cholesterol (TC), and triglycerides (TG) levels in the C+HS group. Cfa-miRNA-122 and -34a expression discriminated the diseased groups from the control group better than traditional serum-derived liver biomarkers, as evidenced by areas under the receiver operating characteristic (AUC-ROC) curve of 0.99 and 0.97 for cfa-miRNA-122 expression in the C+HS and C+HF groups, and 1.0 and 0.96 for cfa-miRNA-34a in the C+HS and C+HF groups, respectively. Cfa-miRNA-21 expression was upregulated only in the C+HF group compared with the C+HS (P < .01) and control (P < .001) groups and showed a positive correlation with serum ALT, AST, TBIL, ALP, and GGT and negative correlation with serum TC and TG levels. Cfa-miRNA-21 expression could also differentiate the C+HF group from the control and C+HS groups with a diagnostic performance superior to that of the conventional serum biochemical variables as evidenced by AUCs of 1.0 and 0.98, respectively.

Conclusions: Serum cfa-miRNA-122, -34a, and -21 expression was significantly upregulated in dogs with cholecystolithiasis with hepatic steatosis or fibrosis compared with control dogs. These miRNAs could serve as novel biomarkers for hepatic steatosis or fibrosis, which have been implicated in the pathogenesis of cholecystolithiasis.

Keywords: Cholelith; cfa-miRNAs; dogs; hyperlipidemia; liver.