Estrogens and experimental atherosclerosis in the baboon (Papio cynocephalus).

Abstract

SUMMARY One hundred twenty-six adult female baboons (Papio cynocephalus) were hysterectomized and all except 18 were ovariectomized. The animals were fed a moderately atherogenic diet (40% calories from hydrogenated vegetable oil, 1.5 mg cholesterol/kcal) for two years. Ovariectomized-hysterectomized animals received estrone sulfate, ethynyl estradiol, or diethylstilbestrol orally in daily doses similar to those given humans. An ovariectomized-hysterectomized group and a hysterectomized group received no drug. The average total serum cholesterol concentration rose from 136 mg/dl to 223 mg/dl and declined to 186 mg/dl. Concentrations of cholesterol, THERE ARE CONFLICTING OBSERVATIONS on the relationship between estrogens and atherogenesis in both humans and experimental animals. Premenopausal white women consistently have a lower incidence and prevalence of myocardial infarctionl-' and a lessened extent of advanced atherosclerotic lesions in the coronary arteries5' 6 than do white men of the same age. However, some studies show that women ovariectomized before the natural menopause lose their relative immunity to coronary heart disease,7-9 while others find no effect of ovariectomy.0' 11 One study finds atherosclerosis more severe in ovariectomized women,'2 but another finds no difference." According to observations from The Framingham Study, postmenopausal women have a higher incidence of coronary heart disease than age-matched premenopausal women.'4 Despite a prevailing impression that the menopause increases risk of coronary heart disease, age and sex specific mortality rates do not increase after the menopause more than would be expected with age.3' 15 "16 Attempts to reduce the incidence of coronary heart disease in postmenopausal women by estrogen replacement therapy also have yielded conflicting results.'7 '9The results of animal experiments on the relationship between estrogens and atherogenesis are as inconsistent as those from human studies. Estrogens induced hyperlipidemia in chickens20 but inhibited coronary artery lipidosis in cockerels21; reduced the size of plaques in White Carneau pigeons in high doses22-24; produced a variety of triglyceride, and phospholipid in whole serum, low density lipoproteins and high density lipoproteins showed no consistent statistically significant differences among the groups. Triglyceride and phospholipid concentrations were higher in the estrogen-treated and intactovary groups than in the ovariectomized nonestrogen treated group, but not all pairwise comparisons were statistically significant. There were no consistent statistically significant differences in atherosclerotic lesions among the groups. Neither ovariectomy nor estrogen replacement influence diet-induced experimental atherosclerosis in the baboon within two years. changes in arteries of rats25 28; and augmented, inhibited, and failed to affect diet-induced hypercholesterolemia and atherosclerosis in rabbits.29 32In the hope of resolving some of these conflicting observations, this experiment was planned t...

Diet‐induced early‐stage atherosclerosis in baboons: Lipoproteins, atherogenesis, and arterial compliance

“…Aortic arch atherosclerosis is an independent risk factor for ischemic stroke and recurrent vascular events 24–26 ; atherosclerosis in the thoracic aorta is strongly predictive of generalized atherosclerosis 24 and coronary artery disease 27, 28 ; and the common iliac arteries are the second most frequently affected blood vessels (after the arteries of the thigh) in atherosclerotic peripheral artery disease 29 . These associations have been replicated in earlier studies of baboons from this same pedigreed breeding colony 30, 31 .…”

Oral Contraceptive Hypertension and Thromboembolism

“…Structural and histochemical vascular changes have also been noted at postmortem in women on OCs who died unexpectedly of thromboembolic disease. Atherosclerosis was not a common finding in these cases ( 41,43). Other changes, similar to those noted in animals, were found in the vascular intimae of these young victims of OC use.…”

Carrageenan: a review

“…Male and female infant baboons were reared from birth to 112 days of age on infant formula containing 0, 1, or 5% kappa/lambda-carrageenan derived from C. crispus. No effect was seen on organ or body weights, characteristics of the urine and faeces, gross findings, haematological or clinical chemical variables, or the gross or microscopic appearance of the gastrointestinal tract (McGill et al 1977). Groups of 10 male and 10 female Sprague-Dawley rats were fed 0 or 5% conventionally processed iota-carrageenan from E. spinosum and kappacarrageenan from E. cottonii in the diet for periods of over 90 days.…”