Dipeptidyl peptidase 4 inhibitor reduces intimal hyperplasia in rabbit autologous jugular vein graft under poor distal runoff

Abstract

Dipeptidyl peptidase 4 inhibitors are widely used in patients with type 2 diabetes mellitus to accomplish glycemic control through an increase in the blood glucagon-like peptide 1 (GLP-1) concentration. These agents also inhibit vascular inflammation (eg, in atherosclerosis). This study was undertaken to determine whether and how vildagliptin (a potent dipeptidyl peptidase 4 inhibitor) might reduce intimal hyperplasia in vein grafts. Twelve rabbits were randomly divided into two groups; one group received vildagliptin orally (10mg/kg/d; n= 6), whereas the control group (n= 6) did not. Vildagliptin administration was started 7days before rabbits underwent interposition reversed autologous jugular vein grafting and ended at graft harvesting (28days after the operation). Histochemical changes in the vascular wall were examined, as were changes in the acetylcholine-induced effects on the endothelial Ca(2+) concentration ([Ca(2+)]i) and endothelium-dependent relaxation. Under fasting conditions, vildagliptin increased the plasma GLP-1 concentration, without affecting plasma glucose or insulin. Acetylcholine induced endothelium-dependent relaxation only in the vildagliptin group, and this was blocked by the nitric oxide synthase inhibitor N(ω)-nitro-l-arginine. Acetylcholine did not modify the endothelial [Ca(2+)]i in either the control or vildagliptin group. Intimal hyperplasia was significantly less in the vildagliptin group (0.11± 0.02mm, n= 5) than in the controls (0.31± 0.06mm, n= 4; P< .01). Vildagliptin increased the plasma GLP-1 concentration. It also enhanced acetylcholine-induced [Ca(2+)]i-independent endothelial nitric oxide release and reduced vein graft intimal hyperplasia, independently of any glycemic control action.