INCREASED SERUM ANGIOTENSIN-CONVERTING ENZYME-ACTIVITY IN TYPE-T INSULIN-DEPENDENT DIABETES-MELLITUS - ITS RELATION TO METABOLIC CONTROL AND DIABETIC COMPLICATIONS
Dj. Vandyk et al., INCREASED SERUM ANGIOTENSIN-CONVERTING ENZYME-ACTIVITY IN TYPE-T INSULIN-DEPENDENT DIABETES-MELLITUS - ITS RELATION TO METABOLIC CONTROL AND DIABETIC COMPLICATIONS, European journal of clinical investigation, 24(7), 1994, pp. 463-467
Serum angiotensin-converting enzyme (ACE) was measured in 150 insulin-
dependent diabetes mellitus (IDDM) patients and 72 healthy subjects by
radioassay, using [H-3]-hippuryl-glycyl-glycine as a substrate. Mean
(SD) serum ACE activity in diabetic patients was 120 +/- 33 nmol ml(-1
) min(-1) (range 46-215) and was significantly increased by 56% compar
ed to control values (77+/-23 nmol ml(-1) min(-1), range 46-125, P < 0
.001). ACE activity > 125 nmol ml(-1) min(-1) was observed in 60 of 15
0 IDDM patients. 96 IDDM patients were normoalbuminuric (< 22 mg 24 h(
-1)) and 49 patients were micro- or macroalbuminuric (range 22-6010 mg
24 h(-1)). Micro- and macroalbuminuric IDDM patients were found to ha
ve significantly greater ACE activity values than normoalbuminuric pat
ients (128+/-36 vs. 115+/-30 nmol ml(-1) min(-1), P=0.025). Metabolica
lly well-controlled IDDM patients (glycosylated haemoglobin less than
or equal to 8%) had lower ACE activity values than the patients with g
lycosylated haemoglobin greater than 8% (109+/-20 vs. 127+/-32 nmol ml
(-1) min(-1), P < 0.02), A significant correlation between degree of m
etabolic control and ACE activity was found (r=0.435, P<0.001) so that
an increase in one glycosylated quartile unit is accompanied by an in
crease in ACE activity of 10.5 nmol ml(-1) min(-1). Thus ACE activity
in the serum of IDDM patients was increased by 56% in 40% of the patie
nts. It was increased in IDDM patients without complications and in pa
tients with retinopathy or nephropathy. In diabetic patients with neph
ropathy, ACE activity was greater than in diabetic patients without ne
phropathy. ACE activity was positively correlated with metabolic contr
ol. The role of increased ACE activity in the development of diabetic
nephropathy remains to be established.