Arterial cholesterol content and collagen metabolism in cynomolgus monkeys

The activity of prolyl hydroxylase and the rate of collagen synthesis were examined in two anatomically different arterial segments of cholesterol-fold cynomolgus monkeys. In the aortic arch vessels the activity of prolyl hydroxylase was increased after six months on a high fat and high cholesterol diet. In this tissue the enzyme activity showed positive correlation with the levels of plasma and tissue cholesterol content. By contrast in the abdominal aortas of the same animals no significant increase of arterial tissue cholesterol or prolyl hydroxylase activity was seen. Despite the elevation of prolyl hydroxylase activity in the arch vessels of hyper cholesterolemic animals, no concomitant increase of collagen synthesis was seen. Neither cholesterolemia nor arterial cholesterol showed a positive correlation with the rate of arterial collagen synthesis. No significant changes of the rate of collagen metabolism were detected at the end of an 18 months intervention phase when the cholesterol content both in plasma and in the arterial tissue was substantially reduced.