The Effect of Diabetic Control on the Width of Skeletal-Muscle Capillary Basement Membrane in Patients with Type I Diabetes Mellitus

We studied the relation between the control of blood glucose and the width of skeletal-muscle capillary basement membrane in 23 insulin-dependent (Type I) diabetic patients. After initial measurement of levels of glycosylated hemoglobin and width of skeletal-muscle capillary basement membrane, the patients were divided into two groups: an experimental group of 13 patients who were treated with continuous subcutaneous insulin infusion, and a control group of 10 patients who continued to receive conventional treatment — usually two injections of insulin daily. After two years, the experimental group had a significant decrease in glycosylated hemoglobin levels as compared with base-line values (mean±S.E.M., 7.6±0.4 vs. 10.2±0.7 per cent; P<0.001), reflecting improved control of blood glucose, and a significant reduction in the width of skeletal-muscle capillary basement membrane (1293±68 vs. 1717±182 Å; P<0.05). The control group of patients had no significant change in their levels of glycosylated hemoglobin or in the width of their skeletal-muscle capillary basement membranes. If changes in the capillaries in skeletal muscle parallel those in the capillaries in retinal or renal tissue, then meticulous control of blood glucose may be beneficial over time in preventing the microvascular complications of diabetes. (N Engl J Med 1983; 309:1546–50). The relation between the microvascular complications of diabetes mellitus and blood glucose control is unknown,¹ although this issue has been the subject of long-standing theoretical controversy.^2,3 The inability to identify the relation is a function of the inability to achieve long-term normalization of blood glucose levels in most diabetic patients. Over the past few years the development of new technology and the use of innovative treatment programs has made possible long-term maintenance of nearly normal levels of glycemia in many insulin-dependent diabetic patients.^{4 5 6} In most tissues affected by diabetic microvascular disease, especially the eye and kidney, a characteristic finding is.