Bile microRNAs as postmortem indicators of liver histopathology in forensic autopsy cases

Assessment of antemortem liver condition is often challenging in forensic autopsy, particularly when macroscopic findings are inconclusive and conventional postmortem biochemical markers are unreliable. MicroRNAs (miRNAs) are relatively resistant to degradation and may remain detectable in postmortem samples. Bile, a hepatocyte-derived biological fluid, represents an attractive but underexplored matrix for postmortem molecular analysis. In this study, bile samples were collected during forensic autopsy from cases with normal liver, fatty liver, and liver cirrhosis. MicroRNA expression profiles were first explored using next-generation sequencing, followed by differential expression analysis with TCC-GUI. Based on these exploratory results, selected miRNAs were quantitatively validated using quantitative real-time PCR. Distinct bile miRNA expression patterns were observed among the three histopathological groups. Quantitative PCR analysis demonstrated significantly reduced expression levels of miR-17, miR-29a, miR-29c, miR-194, and miR-200a in fatty liver and liver cirrhosis compared with normal liver, and miR-126 expression was significantly lower in liver cirrhosis cases. These findings indicate that bile miRNA expression profiles vary according to liver histopathological status in forensic autopsy cases. The present data support a preliminary, group-level association and suggest that bile miRNAs may provide supplementary information on morphological liver pathology, although controlled postmortem stability studies and larger age-matched cohorts are required before diagnostic or cause-of-death applications can be established.