IMPROVEMENT IN ENDOTHELIAL FUNCTION BY ANGIOTENSIN-CONVERTING ENZYME-INHIBITION IN INSULIN-DEPENDENT DIABETES-MELLITUS

We postulated that nitric oxide (NO)-mediated endothelial function wou ld be improved by acute and short-term treatment with an angiotensin c onverting enzyme (ACE) inhibitor in patients with type I diabetes mell itus, in whom endothelial function is depressed, Nine type I diabetic patients and eight healthy subjects underwent forearm blood flow measu rement using strain gauge plethysmography during intraarterial infusio n of incremental doses of endothelium-dependent (acetylcholine [ACh]) and endothelium-independent (sodium nitroprusside [SNP]) vasodilators. Pretreatment ACh responses were depressed in diabetic patients relati ve to the normal subjects (P < 0.05), No difference between the groups was evident in response to SNP, Acute ACE inhibition (with intrabrach ial enalaprilat) enhanced ACh responses in the diabetic patients (P < 0.005), with a further improvement evident after 1 mo of oral therapy with enalapril (P < 0.001) when ACh responses were normalized, ACE inh ibition did not affect SNP responses, We conclude that acute administr ation of the ACE inhibitor, enalaprilat, enhances NO-mediated endothel ial function in type I diabetic patients, with further improvement evi dent after 4 wk of enalapril therapy.