Quadriceps and myocardial capillary basal laminae. Their comparison in diabetic patients.

Quadriceps and myocardial biopsy specimens were obtained from 24 patients undergoing elective coronary arterial bypass grafting. Patients were divided into those with chemical diabetes (CD) (with incidentally discovered elevated glucose levels when stressed), overt diabetes (OD) (who required insulin support), and euglycemic nondiabetics (ND). Specimens from the quadriceps femoris and left anterior apical segment of the heart were examined ultrastructurally, with particular attention to the evaluation of capillary basal laminar thickness, using morphometric techniques. Results indicate (1) an increased, though statistically insignificant, thickening of capillary basal laminae in the quadriceps of CD and OD patients, in contrast with statistically significant laminar thickening in the diabetic myocardium; (2) early, mild laminar thickening in quadriceps and myocardium of the asymptomatic CD group; and (3) two characteristic patterns of basal laminar contours, homogeneous and lamellated, the latter being seen prominently in the quadriceps of diabetic patients in frequent association with pericapillary edema. These findings support the concept that basal laminar thickening in the diabetic is associated with deranged carbohydrate metabolism.