[Increase of activity of angiotensin-converting enzyme in insulin-dependent diabetic patients with permanent microalbuminuria].

Angiotensin I Converting Enzyme (ACE), which is synthesized by vascular endothelial cells, can be elevated in some diabetic subjects. To study if serum ACE can be elevated in subjects with high risk for malignant microangiopathy, 34 normotensive type I, insulin-dependent diabetic subjects with persistent microalbuminuria (30-300 mg/24 h) were compared for serum ACE activity (Liebermann's method) with 30 normotensive, normoalbuminuric type I, insulin-dependent diabetic subjects of same age (33 +/- 15 (M +/- SD) vs 39 +/- 14 years), sex (13 F/21 M vs 15 F/15 M), stage of retinopathy (14 vs 16 nil/11 vs 7 background/6 vs 4 preproliferative/3 vs 3 proliferative), HbA1c (7.7 +/- .9 vs 8.2 +/- 1.0%). Serum ACE activity of diabetic subjects were also compared with 120 age and sex related healthy controls. Serum ACE activity was higher in type I, insulin-dependent diabetic subjects with microalbuminuria than in those with normoalbuminuria (406 +/- 114 vs 359 +/- 97 IU/l; p = 0.05), or in controls (307 +/- 95 IU/l; p = 0.0001). Normoalbuminuric subjects also had higher ACE activity than controls (p = 0.02). In diabetic subjects, serum ACE activity was not related to diabetes duration (r = 0.1; ns), stage of retinopathy (r = 0.06; ns), HbA1c (r = 0.02; ns), or to blood pressure (r = 0.03; ns), but was related to urinary albumin excretion (r = 0.28; p = 0.03) in diabetic subjects. However, stage of retinopathy was related to diabetes duration (r = 0.74; p = 0.0004) and to age (r = 0.42; p = 0.003) in these subjects.(ABSTRACT TRUNCATED AT 250 WORDS)