Combination of Estrogen Replacement and Exercise Protects Against HDL Oxidation in Post-Menopausal Women
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The incidence of atherosclerosis and cardiovascular disease (CVD) in women increases following menopause and has been associated with a reduction in circulating estrogen. Increased CVD risk is also perpetuated by sedentary lifestyle. Growing evidence indicates that oxidation of lipoproteins leads to a powerful immune response, disruption of normal lipoprotein function, and deposition of atherosclerotic plaques. For example, once high-density lipoproteins (HDL) are oxidized, they lose the ability to a) participate in reverse transport of cholesterol to the liver, and b) protect low-density lipoproteins (LDL) against oxidation. The purpose of this study was to determine the effects of combining estrogen replacement and exercise upon lipid peroxidation of the HDL fraction (HDL-ox). Blood samples were drawn from 34 post-menopausal women from four groups: women who were not receiving estrogen replacement and who were sedentary (NSD) (n = 9); women who were not receiving estrogen replacement and who were participating in regular exercise (NEX) (n = 8); women who were receiving estrogen replacement and who were sedentary (ESD) (n = 8); and women who were receiving estrogen replacement and who were participating in regular exercise (EEX) (n = 9). Total-HDL cholesterol was significantly higher (p<0.05) in EEX when compared with NEX, NSD, and ESD. HDL-ox was assessed via malondialdehyde (MDA). Mean (+/- SEM) values for HDL MDA expressed in nM are as follows: NSD = 903.3 +/- 118.4; NEX = 1226.7 +/- 247.7; ESD = 876.7 +/- 116.3; EEX = 537.4 +/- 74.8. EEX lipid peroxidation was significantly (p = 0.02) lower than NEX. Lipid peroxidation tended to be lower in EEX than in NSD and ESD (p = 0.07). These data indicate that the combination of estrogen replacement and regular exercise in post-menopausal women may be most effective in reducing oxidation of HDL in vivo.
author list (cited authors)
Lawler, J. M., Hu, Z., Green, J. S., Crouse, S. F., Grandjean, P. W., & Bounds, R. G.