Introduction
Estrogen is a female sex hormone that has important metabolic functions. The level of this hormone decreases after menopause, and the cardioprotective effect of estrogen is reduced and shows menopausal symptoms. Short-term effects like hot flashes following menopause are due to changes in hormone levels. Atherosclerosis, plaque accumulation, and other cardiovascular diseases commonly occur in women after menopause. Hormonal replacement therapy is important to reduce the symptoms and increase the cardioprotective.
What Is Hormone Replacement Therapy?
After menopause in females, the body no longer produces estrogen and progesterone. The changes in hormone levels can cause the following symptoms.
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Night sweat.
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Hot flashes.
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Pain during sex.
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Insomnia.
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Mood swings.
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Depression.
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Irritability.
Through hormone replacement therapy, the hormones are given and help boost the hormone levels, and the symptoms of menopause are relieved. There are two types of hormone replacement therapy.
1. Estrogen Therapy:
The hormone estrogen alone is taken at prescribed low doses in the form of pills or patches. Also, estrogen in the form of cream and vaginal spray is used to avoid vaginal dryness. This helps prevent the symptoms of menopause.
2. Estrogen Progesterone or Progestin Hormone Therapy:
Similar to estrogen replacement, estrogen-progesterone combination therapy is done. Progestin is a synthetic form of progesterone that is also used in EPT.
What Is the Role of Estrogen and Progesterone in Females?
Estrogen:
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Influence on body calcium utilization.
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Maintain cholesterol level.
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Maintains vaginal health.
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Prevent osteoporosis.
Progesterone:
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Maintains pregnancy.
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Regulation of blood pressure.
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Enhances mood.
What Are the Effects of Hormone Replacement Therapy on the Cardiovascular System?
Coronary Heart Disease:
The disease of the blood vessels of the heart causing thinning and reduced blood flow is called coronary heart disease and is a leading cause of mortality. The factors that contribute to coronary heart disease are smoking, physical inactivity, and diet. Genetics and environmental factors also can be major causes.
Females develop coronary heart disease at a later age than males. Women at premenopausal age have a very low risk of developing coronary heart disease due to the cardioprotective action of estrogen. After attaining menopause, decreases in the level of estrogen increase the risk for heart disease.
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After HRT, the level of low-density lipoprotein particles and the clearance from circulation also increase. Thua reduces the chances of their retention in the arterial wall.
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Estrogen also increases the level of high-density lipoprotein, which is called good cholesterol.
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The effect depends on the route of administration and dose.
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Triglycerides are increased in the oral administration of estrogen and reduced with the addition of androgenic progestins.
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The triglyceride level is reduced in the transdermal application, and the risk of coronary heart disease is reduced.
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The risk for coronary heart disease increases with tissue resistance to insulin. Estrogen has a beneficial effect on the reduction of insulin resistance.
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Hormone replacement therapy results in a reduction of central fat accumulation and reduces an important risk factor for cardiovascular disease.
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Hormone replacement therapy increases coagulation activation and reduces the risk of Venous thromboembolism.
Effect of Estrogen on Vascular Function:
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Estrogen increases the level of a potent vasodilator called nitric oxide, which helps in the regulation of blood pressure and platelet function. Oral and transdermal estrogen have anti-inflammatory effects on blood vessels.
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Improves vasodilation and arterial function.
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Reduces the level of angiotensin-converting enzyme, which positively affects the cardiovascular system.
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Abnormal deposition and remodeling is an important factor in developing atherosclerosis. In HRT, the low doses of estrogen increase the production of matrix metalloproteinase (MMPs) and regulate the remodeling mechanism. High levels of estrogen can cause increased production of MMPs and result in excessive remodeling. So, the dose of estrogen is also an essential factor.
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The renin-angiotensin aldosterone (RAA) system helps in the regulation of blood pressure, and estrogen has a positive role in the regulation of the RAA system.
Athero-protective Effect of Hormone Therapy:
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Women who received hormone therapy should reduce the incidence of common carotid artery intima-media thickness.
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Age and time since they started the hormone therapy, are important, and underlying healthy endothelium is needed for hormone therapy to have an athero-protective effect.
What Is Called the Estrogen Cardioprotective Hypothesis?
Randomized controlled trials demonstrated three important points.
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Hormone therapy reduces the mortality rate and potentially reduces heart disease in younger and not in the postmenopausal age group.
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Duration of hormone therapy is crucial in expressing the benefits of total mortality and heart diseases.
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The risk of hormone replacement therapy is rare in postmenopausal women compared to those who received prevention therapies for coronary heart diseases.
What Are the Effects of Age and Time of Hormone Therapy?
The other major factors that help in the cardioprotective function of the heart are the time of initiation of hormone therapy and the time since menopause. The duration of the therapy is also an important factor. The risks associated with cardiovascular diseases are rare in women who initiate the therapy below 60 years of age or within five years of menopause.
Having a healthy endothelium is important for its response to estrogen. The vasodilatory effects decrease with increasing age. In a patient with atherosclerosis, the impact of estrogen will be very low, or the hormonal therapy is too late to have the cardioprotective effect.
What Are the Risks Associated With Hormonal Replacement Therapy?
The risks associated with HRT are very low and depend on the type of hormone replacement and duration of therapy.
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Breast Cancer: In combined HRT, there is a very low risk of breast cancer, and there is no or little associated risk with estrogen-only HRT.
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Blood Clots: Using HRT patches or gels will not cause any risk of blood clots. HRT tablets can increase the risk of blood clots, but very less.
In total, the benefits outweigh the risks associated with hormonal replacement therapy.
Conclusion
The possible beneficial effect of estrogen on the cardiovascular system includes the regulation of blood pressure, the production of good cholesterol, and reducing the level of bad cholesterol. The effects include improving peripheral glucose metabolism, insulin resistance, vasodilation, and antiplatelet action. Hormonal replacement therapy has an important role in the regulation of various hormone levels and the prevention of coronary heart disease.
