Small vessel disease in vasectomized diabetic monkeys: light microscopic study.

The following four groups of rhesus monkeys were studied for small vessel pathology of the heart, kidney and retina: sham-vasectomized, vasectomized, sham-vasectomized diabetic and vasectomized diabetic. A significant increase was observed in the frequency of pathological changes in small vessels (less than 60 micron diameter), of the heart muscle of nondiabetic vasectomized monkeys, and in sham-vasectomized and vasectomized diabetic monkeys. Further, the thickness of the glomerular capillary basement membrane was also significantly increased in the three experimental groups. In vasectomized diabetic monkeys, the vascular lesions were much greater than in the other two groups. Moreover, in this group one animal had a microaneurysm of a retinal vessel and another had distortion of retinal veins. The monkeys subjected to vasectomy or diabetes alone did not develop these changes. However, the ratio of mural to endothelial cells in retinal vessels was markedly altered in vasectomized and nonvasectomized diabetic monkeys.