Diet and vasectomy: effects on atherogenesis in cynomolgus macaques.

We report here the effect of a moderately atherogenic diet on the progression of atherosclerosis among cynomolgus macaques that were either vasectomized or sham vasectomized. Both groups were compared to sham vasectomized monkeys fed a control Monkey Chow diet. As expected, slight hyperlipoproteinemia induced by the moderately atherogenic diet increased endothelial cell replication rates and resulted in the development of intimal lesions among sham vasectomized monkeys. Unexpectedly, vasectomy resulted in reduced leukocyte adherence to arterial surfaces, reduced endothelial cell replication rates in response to the moderately atherogenic diet, and at most arterial sites, smaller intimal lesions were produced. These data suggest that with slight hyperlipoproteinemia vasectomy may result in a small protective effect against atherosclerosis, while other studies have shown that marked hyperlipoproteinemia in cynomolgus macaques along with vasectomy results in exacerbation of atherogenesis.