Drug-induced reversal of early diabetic microangiopathy.

We performed three oral glucose-tolerance tests and three muscle biopsies over a period of approximately three years in 41 asymptomatic patients with chemical diabetes. At base line, 13 (32 per cent) had an increased capillary basement-membrane width in muscle. Twenty-three patients received glipizide, a new oral hypoglycemic compound, and 18 received placebo. In the patients receiving placebo the mean width of the muscle capillary basement membrane increased from 135.9 +/- 9.0 nm (S.E.M.) to 169.3 +/- 9.5 nm (P = 0.01), but in those receiving glipizide the value decreased to a level no different from that in subjects without diabetes: from 152.9 +/- 2.9 to 127.5 +/- 5.1 nm (P = 0.01). These findings suggest that microangiopathy, as indicated by an increased capillary basement-membrane width in muscle, may be present in a considerable number of patients with asymptomatic diabetes and that the changes can be reversed by early drug treatment.