Alogliptin, a Dipeptidyl Peptidase-4 Inhibitor, Alleviates Atrial Remodeling and Improves Mitochondrial Function and Biogenesis in Diabetic Rabbits

Background-There is increasing evidence implicating atrial mitochondrial dysfunction in the pathogenesis of atrial fibrillation. In this study, we explored whether alogliptin, a dipeptidyl peptidase-4 inhibitor, can prevent mitochondrial dysfunction and atrial remodeling in a diabetic rabbit model. Methods and Results-A total of 90 rabbits were randomized into 3 groups as follows: control group (n=30), alloxan-induced diabetes mellitus group (n=30), and alogliptin-treated (12.5 mg/kg per day for 8 weeks) diabetes mellitus group (n=30). Echocardiographic and hemodynamic assessments were performed in vivo. The serum concentrations of glucagon-like peptide-1, insulin, and inflammatory and oxidative stress markers were measured. Electrophysiological properties of Langendorff-perfused rabbit hearts were assessed. Mitochondrial morphology, respiratory function, membrane potential, and reactive oxygen species generation rate were assessed. The protein expression of transforming growth factor beta 1, nuclear factor kappa B p65, and mitochondrial biogenesis-related proteins were measured by Western blot analysis. Diabetic rabbits exhibited left ventricular hypertrophy and left atrial dilation without obvious hemodynamic abnormalities, and all of these changes were attenuated by alogliptin. Compared with the control group, higher atrial fibrillation inducibility in the diabetes mellitus group was observed, and markedly reduced by alogliptin. Alogliptin decreased mitochondrial reactive oxygen species production rate, prevented mitochondrial membrane depolarization, and alleviated mitochondrial swelling in diabetic rabbits. It also improved mitochondrial biogenesis by peroxisome proliferator-activated receptor-gamma coactivator 1 alpha/nuclear respiratory factor-1/mitochondrial transcription factor A signaling regulated by adiponectin/AMP-activated protein kinase. Conclusions--Dipeptidyl peptidase-4 inhibitors can prevent atrial fibrillation by reversing electrophysiological abnormalities, improving mitochondrial function, and promoting mitochondrial biogenesis.