Epigenetic Therapy for the Treatment of Hypertension-Induced Cardiac Hypertrophy and Fibrosis

The development of heart failure is associated with changes in the size, shape, and structure of the heart that has a negative impact on cardiac function. These pathological changes involve excessive extracellular matrix deposition within the myocardial interstitium and myocyte hypertrophy. Alterations in fibroblast phenotype and myocyte activity are associated with reprogramming of gene transcriptional profiles that likely requires epigenetic alterations in chromatin structure. The aim of our work was to investigate the potential of a currently licensed anticancer epigenetic modifier as a treatment option for cardiac diseases associated with hypertension-induced cardiac hypertrophy and fibrosis. Methods and Results: The effects of DNA methylation inhibition with 5-azacytidine (5-aza) were examined in a human primary fibroblast cell line and in a spontaneously hypertensive rat (SHR) model. The results from this work allude to novel in vivo antifibrotic and antihypertrophic actions of 5-aza. Administration of the DNA methylation inhibitor significantly improved several echocardiographic parameters associated with hypertrophy and diastolic dysfunction. Myocardial collagen levels and myocyte size were reduced in 5-aza-treated SHRs. These findings are supported by beneficial in vitro effects in cardiac fibroblasts. Collagen I, collagen III, and a-smooth muscle actin were reduced in a human ventricular cardiac fibroblast cell line treated with 5-aza. Conclusion: These findings suggest a role for epigenetic modifications in contributing to the profibrotic and hypertrophic changes evident during disease progression. Ther- apeutic intervention with 5-aza demonstrated favorable effects highlighting the potential use of this epigenetic modifier as a treatment option for cardiac pathologies associated with hypertrophy and fibrosis. Keywords