Tissue MicroRNAs in Arrhythmogenic Cardiomyopathy: A Systematic Review of Studies in Human Myocardium and Animal Models with Implications for Post-Mortem Molecular Diagnostics.

Arrhythmogenic cardiomyopathy (ACM/ARVC) is an inherited myocardial disease characterized by progressive fibro-fatty replacement, ventricular arrhythmias, and an increased risk of sudden cardiac death. In addition to mutations in desmosomal genes, growing evidence suggests that microRNAs (miRNAs) actively contribute to disease pathogenesis by regulating key processes such as fibrosis, cell adhesion, and cardiac remodeling. This systematic review analyzed the main miRNAs identified in studies of human cardiac tissue and animal models of ARVC. MATERIALS AND METHODS: Studies based on human myocardial tissue analysis (including autopsy and biopsy samples) and animal models of arrhythmogenic cardiomyopathy were included, using RNA sequencing, small RNA sequencing, miRNA arrays, and RT-qPCR. Studies on circulating miRNAs and narrative reviews were excluded. miRNAs were analyzed in relation to their functional pathways and their role in disease pathogenesis. RESULTS: The synthesis of studies on human and animal cardiac tissue reveals a consistent miRNA signature associated with arrhythmogenic cardiomyopathy. MiR-21-5p and miR-29b-3p are associated with fibrosis and extracellular matrix remodeling, whereas miR-133a-b and miR-130a are linked to cardiomyocyte integrity loss and desmosomal dysfunction. A second group of miRNAs, including miR-217-5p, miR-708-5p, and miR-135b, regulates key pathways such as Wnt/β-catenin and Hippo signaling, contributing to structural remodeling and loss of cellular identity. Furthermore, downregulation of miR-499-5p is associated with mitochondrial dysfunction and cellular vulnerability, while the miR-142-3p, miR-182-5p, and miR-183-5p clusters contribute to differential molecular signatures compared with other cardiomyopathies. Overall, miRNAs converge on three main pathogenic axes: myocardial fibrosis, desmosomal impairment, and remodeling of cellular signaling pathways. CONCLUSIONS: The available evidence indicates that arrhythmogenic cardiomyopathy is regulated by a coordinated network of miRNAs that actively drives myocardial damage progression. These miRNAs represent not only biomarkers but also functional mediators of disease, suggesting potential diagnostic and therapeutic applications based on tissue-specific molecular signatures, including in post-mortem settings.