Skeletal muscle capillaries in diabetics. A quantitative analysis

Capillary sizes, the amounts of endothelium, pericytes, basal lamina (BL), and lumina were measured with planimeter on electron micrographs of 20 capillary cross sections from each of 40 skeletal muscle specimens obtained from any of eight specific body sites of 20 diabetics. While the capillaries in the distal abdomen and the proximal thigh do not have thickened BL, those in the muscles of mid-abdomen, chest wall, hand, mid-thigh, mid-lower leg, and foot have significantly increased amounts of BL. The remaining parameters differ among body sites, generally following a pattern established earlier for the skeletal muscle capillaries of nondiabetics. Because of the focal and regional distribution of BL thickening and because it occurs also in nondiabetics, it is concluded that BL thickening is a common but not characteristic feature of diabetes mellitus. A possible mechanism which may lead to BL thickening is proposed and discussed.