MicroRNA-34a and tert act as epi-drivers of cardiac telomere length and polygenic cardiac hypertrophy

Cardiac hypertrophy is one of the main risk factors forheart failure. Here we aimed to investigate whether cardiactelomere length contributes to polygenic cardiac hypertro-phy independent of blood pressure. We also investigatedwhether changes in telomere length were due to the telomereregulators microRNA-34a,Ppp1r10(also known asPnuts)and telomerase. We used the hypertrophic heart rat (HHR),a normotensive model of polygenetic cardiac hypertrophy,and compared it to age-matched controls. Telomere length, microRNA levels, gene expression and telomerase activitywere measured in isolated cardiomyocytes and left ventricletissue using real-time PCR. Telomere length was significantlylonger in 2-day and 38-week-old HHR, but shorter at 4-and 13-week HHR. In the HHR, telomere length becameshorter early in development, while in the control straintelomere shortening was only observed in late adulthood.Telomere length was the main determinant of cardiac mass