Endothelial dysfunction of conduit arteries in insulin-dependent diabetes mellitus without microalbuminuria

Previous studies have shown that endothelial dysfunction, an early sign of atherosclerosis, occurs in animal models of diabetes mellitus and in resistance vessels of patients with insulin-dependent diabetes. In the present study we examined whether young patients with insulin-dependent diabetes without microalbuminuria present abnormal endothelial function of large peripheral arteries.

Twenty-six patients with insulin-dependent diabetes without microalbuminuria were compared with 26 normal controls and 5 patients with insulin-dependent diabetes with microalbuminuria. Brachial artery diameter was measured at rest, during reactive hyperaemic flow (endothelium-dependent dilatation) and after sublingual isosorbide dinitrate (endothelium-independent dilatation).

Baseline artery diameter and flow as well as the degree of reactive hyperaemia were similar in all groups compared to controls. Flow-mediated dilatation was lower in patients with diabetes without microalbuminuria (5.8 +/- 7 vs 11 +/- 7%. P = 0.01) as well as in patients with diabetes without microalbuminuria (0.75 +/- 2.5 vs 11 +/- 7%, P = 0.003); nitrate-induced dilatation was normal in patients without microalbuminuria and attenuated in patients with microalbuminuria. In the group of diabetes patients without microalbuminuria, those with disease duration > 10 years and HbAlc > 6% had the worse endothelial function.

Our results demonstrate that endothelial dysfunction of conduit arteries can be detected in patients with insulin-dependent diabetes mellitus without microalbuminuria, probably contributing to the high prevalence of atherosclerosis in these patients.