Angiotensin converting enzyme inhibition and arterial endothelial functionin adults with Type 1 diabetes mellitus

Aims. Arterial endothelial dysfunction is a key early event in atherogenesi s, and occurs in asymptomatic adults with Type I diabetes mellitus (DM). As angiotensin converting enzyme (ACE) inhibitors have been reported to rever se microvascular endothelial dysfunction acutely, we assessed the longer te rm effect of ACE inhibition on large vessel endothelial physiology in a ran domized, crossover double-blind controlled clinical trial. Methods. Flow-mediated arterial dilatation (FMD), which is largely due to e ndothelial release of nitric oxide, was assessed by vascular ultrasound in to Type I DM subjects with known endothelial dysfunction. These subjects, a ged 28 +/- 5 years, were studied before and after It weeks oral therapy wit h either the ACE inhibitor perindopril 4 mg daily or the diuretic hydrene ( triamterene 50 mg with hydrochlorothiazide 25 mg) daily. Results. Although perindopril lowered both systolic and diastolic blood pre ssure by 2.7/3.2 mmHg, respectively (F-3.78 = 4.7, P = 0.006; F-3.78 = 3.2, P = 0.03), there was no significant effect of either perindopril or hydren e on FMD (baseline FMD before perindopril 4.6 +/- 2.5%, after 4.1 +/- 3.4%, baseline FMD before hydrene 5.4 +/- 3.6%, after 6.0 +/- 3.3%; F-3.78 = 1.9 , P = 0.1). Glycaemic control deteriorated slightly on hydrene whilst lipid levels, heart rate, resting blood flow and the arterial responses to nitro glycerine, a smooth muscle dilator, were unaffected by the treatment given. Conclusion. ACE inhibitor therapy for 3 months did not improve arterial end othelial function in Type I DM subjects.