••• CHAPTER 33^ Menopause^319
❍ What contributes to cardioprotection in women?
Higher HDLs, 10 mg/dL higher than in men, an effect of estrogen.
❍ What are the changes in cholesterol fractions at the age of menopause?
HDL decreases, LDL increases, and the average cholesterol increases to levels higher than in men.
❍ What is estrogen’s effect upon lipids and lipoproteins?
It increases HDL and decreases total cholesterol and LDL.
❍ What lipoprotein-independent mechanisms of estrogen may protect against cardiovascular disease?
Vasodilatation, decreased platelet aggregation, decreased smooth muscle cell proliferation of arterial vessels, direct
inotropic actions on the heart, antioxidant activity, favorable impact on clotting mechanisms, inhibition of intimal
thickening, inhibition of macrophage foam cell formation, improved glucose metabolism, and decreased insulin
levels.
❍ Are estrogen and progesterone receptors present in the vascular tree?
Yes. In the endothelium and smooth muscles of arterial vessels.
❍ How does estrogen exert a cardioprotective effect through the vasculature?
Vasodilatation and decreased peripheral resistance.
❍ How does estrogen exert cardioprotection via endothelium-dependent mechanisms?
Augmentation of nitric oxide and prostacyclin leading to vasodilation and decreased platelet aggregation.
❍ What direct effects does estrogen have on the heart?
Increases left ventricular diastolic filling and stroke volume, delaying age-related decreases in compliance.
❍ What effect does acute administration of estradiol have on myocardial ischemia in women with coronary
artery disease?
Signs of ischemia on electrocardiograms are delayed and exercise tolerance is increased.
❍ How does estrogen decrease LDL levels?
It increases hepatic LDL catabolism and increases LDL receptors.
❍ How does estrogen increase HDL levels?
It inhibits hepatic lipase activity.
❍ How does estrogen replacement therapy exert an antioxidant cardioprotective effect?
It inhibits LDL oxidation and resultant endothelial vasospasm.
❍ What other antioxidants may decrease the risk of coronary artery disease?
Vitamin E and b-carotene (the prohormone of vitamin A).