Levels of serum angiotensin-converting enzyme before and after forearm venous stasis in diabetic microangiopathy.

The levels of angiotensin-converting enzyme and Factor VIII-related antigen, 2 endothelial synthesized glycoproteins, were measured in basal conditions and after forearm venous stasis in 12 healthy controls and 12 patients with diabetic microangiopathy. Angiotensin-converting enzyme levels were similar in the controls and in the patients both basally (185 +/- 17 nm/ml/min (SEM) and 192 +/- 15, respectively) and after stasis (238 +/- 17 and 220 +/- 15), whereas Factor VIII-related antigen was lower in the former basally (101 +/- 13% vs 184 +/- 16%, p less than 0.001) and after stasis (140 +/- 21% and 243 +/- 21%, p less than 0.01). It is concluded that Factor VIII-related antigen is a more sensitive indicator of endothelial cell damage in diabetic microangiopathy than angiotensin-converting enzyme.