Microvascular effects of the inhibition of dipeptidylpeptidase IV by linagliptin in nondiabetic hypertensive patients

Abstract

Recent studies suggest vascular benefits of dipeptidylpeptidase IV (DPP-IV) inhibition in patients with diabetes mellitus. Only little is known about potential vascular effects of DPP-IV inhibitors in nondiabetic individuals. The aim of this study was to investigate the effect of DPP-IV inhibition in a nondiabetic hypertensive population. This was a double-blinded, randomized, placebo-controlled, mechanistic study, comparing microvascular effects of the DPP-IV inhibitor linagliptin with placebo in nondiabetic individuals with a history of arterial hypertension. Twenty-one patients received 5 mg linagliptin (5 women; age 67.6 ± 6.0 years; mean ± SD), whereas 22 patients were randomized to placebo (5 women; age 64.8 ± 7.1 years). At baseline, after 6 and 12 weeks, retinal microcirculation and arterial blood pressure profiles were assessed. Moreover, blood samples were taken for the measurement of HbA1c, asymmetric dimethylarginine, C-reactive peptide, cyclic guanosinmonophosphate, transforming growth factor beta (TGF-ß1) and cystatin C. Retinal capillary perfusion increased by 23.7 ± 10.3% (mean ± SEM; P < 0.05), retinal arterial flow by 7.6 ± 0.6 (P < 0.05) and the retinal hyperemic response by 290 ± 263% (P < 0.05) during treatment with linagliptin. No change in retinal blood flow was found in the placebo group. Although blood pressure declined in both groups, a significant decline in TGF-ß1 by 9.3 ± 4.5% (P < 0.05) could only be observed in the linagliptin group. No significant change in other laboratory parameters could be observed in both groups. Our study suggests microvascular and antifibrotic effects of linagliptin in a nondiabetic, hypertensive population.