Nonhuman Primate Models of Menopause (Part 15)
Cynomolgus monkey. Surgically postmenopausal cyno-molgus monkeys on an atherogenic diet, like postmenopausal women, had elevated LDL cholesterol, reduced HDL cholesterol, and increased vasoconstrictor response and coronary artery atherosclerosis relative to control, intact monkeys fed the same diet for the same time. Using continuous exposure to physiologic amounts of estrogen, with or without cyclically administered progestin, over 30 mo, coronary artery atherosclerosis was reduced to approximately half in animals treated with steroid hormone, largely independently of plasma lipid changes. The LDL cholesterol accumulation within coronary and other arteries in ovariectomized cynomolgus monkeys was significantly decreased by estrogen plus progestin treatment. my canadian pharmacy online
In studies focused on vascular reactivity, surgically menopausal monkeys with no ovarian hormone replacement showed coronary artery vasoconstriction after an acetylcholine infusion, whereas their counterparts with physiologic replacement of estradiol had vasodilation after the acetylcholine infusion. Coadministration of progestin attenuated this effect.
Physiologic effects of dietary interventions are more easily studied in NHPs, in which access to diet and environmental conditions are more rigorously controlled than in community-dwelling women. Either soy phytoestrogens or conjugated equine estrogens administered to ovariecto-mized cynomolgus monkeys on a moderately atherogenic diet decreased atherosclerotic plaque progression relative to controls; the conjugated equine estrogen was more effective.
In attempts to make the ovariectomized cynomolgus monkey an even better model for human menopause, an-drostenedione implants will be used to more closely replicate hormonal profiles of postmenopausal women.