Into The Heart was originated July 2007 to help individuals nurture their cardiovascular health and prevent cardiovascular disease.
A section of this blog provides contemporary insight in menopausal hormone replacement, and postmenopausal estrogen replacement options as these therapies effect women’s cardiovascular risk factors such as hypertension, arterial stiffness, glucose regulation, cholesterol metabolism, inflammatory mediators, and oxidative stress. Cardiac contractile function, atrial fibrillation, endothelial function, ischemia and coronary perfusion are also discussed, as these mechanisms are also affected by diminished estrogen and . . . choice of hormone replacement.
The Effects of Estrogen on the Cardiovascular System
Estrogen is a potent cardiovascular agent. Estrogen maintains endothelial cell integrity, decreases expression of adhesion molecules, lowers systemic blood pressure, promotes vasodilation, decreases platelet aggregation, inhibits vascular smooth muscle cell proliferation, decreases circulating ACE activity, possess antioxidant and calcium antagonist activities, inhibits adrenergic responses and down regulates platelet and monocyte reactivity.
Estrogen increases the expression of genes for important vasodilatory enzymes such as prostacyclin synthase and nitric oxide synthase. Prostacyclin is a profound inhibitor of platelet aggregation (build-up). Nitric oxide is a vascular-protective molecule produced by the endothelial cells that line the artery walls. Nitric oxide helps regulate blood pressure and blood flow, and is also anti-atherogenic (lessens fatty buildup in the arteries). Nitric oxide helps to inhibit the proliferation of (arterial) smooth muscle cells in the artery.
Keep in mind . . . oral (pill) hormone replacement, oral estrogen replacement and transdermal (patch, cream or gel) estrogen replacement each have different effects on cholesterol metabolism, inflammatory mediators and other cardiovascular risk factors.
As such, the timing of initiation, the type and mode of hormonal treatment, age and preexisting cardiovascular condition are important factors to be considered when using hormone replacement during the menopausal transition and postmenopausal years.
Below is a listing of scientific studies that explore the mechanisms of action regarding estrogen, estrogen receptors A and B, estrogen metabolites and estrogen replacement on vascular and cardiac function. Keep in mind you can review the content of these studies though an internet search.
1) Mechanisms of Estrogenic Vascular Protection.
Am J Physiology Heart Circ Physiology 290: H507-508, 2006.
2) Medroxyprogesterone Acetate but not Drospirenone
Ablates the Protective Function of 17B Estradiol in Aldosterone Salt Treated Rats.
Hypertension 48:994; 2006.
3) Estrogen Modulation of Endothelial Nitric Oxide Synthase.
Endocrine Review 23 (5): 665-686, 2002.
4) Estrogen Causes Dynamic Alterations in Endothelial Estrogen Receptor Expression.
Circulation Research 91: 814: 2002.
5) Estrogen Receptors Activate Atrial Natriuretic Peptide in the Rat Heart.
PNSA, Sept 2001, Vol.98, No 20, 11765-11770
6) Effects of Estrogen on Aortic Function in Postmenopausal Women.
Am J Physiology Heart Circ Physiology 276: H658-662, 1999.
7) The Protective Effects of Estrogen on the Cardiovascular System.
NEJM Volume 340:1801-1811 Number 23, 1999.
8) Estrogen Replacement Therapy and Cardiovascular Protection.
Gyno Endo 12(1):43-59; Feb 1998.
9) Relationship between Serum Estradiol Levels and the Increases in HDL Levels in Postmenopausal Women Treated with Oral Estrogen.
Journal of Clinical Endocrinology & Metabolism Vol 84. No. 3 985-989
10) Effects of Estrogen Replacement Therapy on Endothelial Function in Peripheral Resistance Arteries in Normotensive and Hypertensive Postmenopausal Women.
Hypertension 2001; 37:651
11) Regular Exercise, Hormone Replacement Therapy and the Age-related Decline in Carotid Arterial Compliance in Healthy Women
Douglas R Seals MD
Cardiovascular Research 2003 57(3):861-868
12) Sex Hormones as Potential Modulators of Vascular Function in Hypertension
Raouf A Khalil MD, PhD
Hypertension 2005;46:249
13) Hormone Replacement Therapy Improves Arterial Stiffness in Normotensive Postmenopausal Women
M Ohmichi MD
Maturitas 45 (4); 293-298. Aug 20, 2003
