Circulating microRNAs in predicting fibrosis in hypertrophic cardiomyopathy: A systematic review.

Background: Hypertrophic cardiomyopathy (HCM) is characterized by left ventricular hypertrophy and interstitial fibrosis, which contribute to adverse outcomes such as heart failure and sudden cardiac death. While cardiac magnetic resonance (CMR) imaging is commonly used to detect myocardial fibrosis, circulating microRNAs (miRNAs) have emerged as promising noninvasive biomarkers for this condition due to their stability in blood plasma and resistance to pH and temperature variance.

Aim: To explore the role of specific circulating miRNAs in identifying myocardial fibrosis in patients with HCM.

Methods: Using PubMed/MEDLINE and Google Scholar, we reviewed studies from 2014 to 2024 examining the link between circulating miRNAs and myocardial fibrosis in HCM. We included studies measuring miRNA expression in blood samples from HCM patients and assessing fibrosis via imaging, mostly CMR. Data extraction concentrated on the population, methodology, and findings related to the correlation between miRNA levels and fibrosis.

Results: Seven studies involving 365 HCM patients with a mean age of 49.37 ± 10.5 years, 116 (31.78%) females, and one animal study identified miR-21, miR-29a, miR-133, miR-4454, and miR-221 as frequently dysregulated markers associated with fibrosis. Elevated levels of miR-21 and miR-29a correlated with more extensive fibrosis, as assessed by late gadolinium enhancement in CMR imaging, with miR-29a consistently linked to both fibrosis and hypertrophy across the studies.

Conclusion: Circulating miRNAs, particularly miR-21, miR-29a, and miR-221, show significant potential as biomarkers for myocardial fibrosis in HCM. Further research should validate these findings and investigate the clinical application of miRNA-based diagnostics in HCM.