Abstract Body: Hypertension-induced ventricular remodeling contributes significantly to the progression of heart failure (HF). The global increase in HF prevalence results in heightened cardiovascular morbidity and mortality, yet treatment options remain limited. The gut microbiota ferments indigestible dietary fibers, producing essential metabolites such as short-chain fatty acids (SCFAs), amino acids metabolites. We hypothesize that direct oral administration of SCFAs modulates mucosal immune cells, thereby ameliorating the heart failure with preserved ejection fraction (HFpEF) phenotype in the double-transgenic rat (dTGR) model.
Four-week-old male rats, double-transgenic for human renin and angiotensinogen (dTGRs), were utilized. These dTGR rats exhibit classical symptoms of HFpEF, including hypertension, inflammation, and fibrosis in the heart and kidneys.
The rats were randomized into five experimental groups: healthy non-transgenic vehicle-treated controls (wild type), vehicle-treated dTGR, and dTGR treated with either acetate, propionate, or butyrate. Following a 3-week treatment period, comprehensive phenotyping was conducted, including echocardiography, Millar-tip catheterization, gene expression analysis, and histological examination.
SCFA administration improves diastolic function, as evidenced by alterations in the end-diastolic pressure-volume relationship measured via Millar-tip catheter. Notably, butyrate treatment had the most pronounced effect on alleviating diastolic dysfunction and reducing blood pressure. Additionally, gene expressions such as atrial natriuretic peptide, connective tissue growth factor, and myosin heavy chain alpha and beta showed improvement in SCFA-treated dTGR HFpEF rats compared to vehicle-treated counterparts. Furthermore, SCFA treatment ameliorated cardiac inflammation.
Our data suggest that SCFAs, particularly butyric acid, enhance hypertensive diastolic dysfunction and cardiac gene expression in dTGR rats, underscoring their therapeutic potential in HF.