Dipeptidyl peptidase-4 inhibitor linagliptin improves fibrosis, apoptosis, and cardiac function in a large animal model of chronic myocardial ischemia.

Interest is increasing in using novel diabetic medications, such as glucagon-like peptide 1 (GLP-1) receptor agonists, to manage coronary artery disease. Dipeptidyl peptidase-4 (DPP-4) inhibitors enhance GLP-1 activity through the same pathway as GLP-1 agonists; however, DPP-4 inhibitors have not been fully evaluated in the setting of ischemic heart disease. We chose to study the DPP-4 inhibitor linagliptin (LIN) in a porcine model of chronic coronary ischemia. Seventeen Yorkshire swine underwent left thoracotomy and ameroid constrictor placement over the left circumflex coronary artery at age 11 weeks. Two weeks thereafter, swine received either vehicle without drug (n = 9) or LIN 2.5 mg (n = 8). Following the elapse of 5 weeks of treatment, swine underwent terminal harvest. LIN significantly increased stroke volume, ejection fraction, cardiac output, and ischemic myocardial perfusion, while decreasing Tau (all P < .05). Trichrome staining showed a marked reduction in ischemic myocardial interstitial and perivascular fibrosis, accompanied by decreased levels of transforming growth factor-β (all P < .05). Apoptosis, measured by terminal deoxynucleotidyl transferase-mediated digoxigenin-deoxyuridine nick-end labeling staining, was significantly reduced, and accompanied by decreases in apoptosis-inducing factor, BCL2-associated agonist of cell death, caspase-9, and cleaved caspase-9 (all P < .05). Additionally, there were significant increases in phosphoinositide 3-kinase, phospho-protein kinase B, 5' adenosine monophosphate-activated protein kinase, phospho-5' adenosine monophosphate-activated protein kinase, and endothelial nitric oxide synthase, and significant reductions in collagen 18 and angiostatin (all P < .05). LIN significantly improved left ventricular function, cellular survival, and attenuated adverse remodeling, all likely secondary to augmented perfusion ischemic myocardial perfusion. Given that this increased perfusion occurred independently of changes in vascular density, treatment likely resulted in enhanced microvascular reactivity. These benefits warrant further investigation of LIN to fully understand its potential as a therapy for ischemic heart disease. SIGNIFICANCE STATEMENT: Linagliptin significantly improved cardiac cellular survival, left ventricular function, and attenuated adverse myocardial remodeling in a clinically relevant, large animal model of chronic ischemic cardiomyopathy. This warrants further investigation of linagliptin to fully understand its therapeutic potential.