Mechanisms of Cardioprotection by Estrogens

Subbiah, M.T.R.

doi:10.3181/00379727-217-44201

Cited by 92 publications

(43 citation statements)

References 60 publications

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“…Epidemiological and case-controlled studies strongly suggest that postmenopausal women have about a 50% reduction in cardiovascular disease with estrogen administration (2,3). At least part of the cardiovascular benefits of estrogens are mediated through changes in lipoproteins (4,5), particularly by increases in high density lipoproteins (HDL); however, there is a strong feeling (6, 7) that as much as 50-75% of the beneficial effect of postmenopausal estrogen therapy is not explained by improvements in circulating lipid levels, but may involve other mechanisms including antioxidant protection (8). Recent studies have shown that a number of estrogens inhibit oxidation of low density lipoproteins (LDL) in vitro and protect against oxidative damage to DNA induced by hydrogen peroxide and arachidonic acid (9)(10)(11)(12).…”

Section: Introductionmentioning

confidence: 99%

Evidence for the role of high density lipoproteins in mediating the antioxidant effect of estrogens

Abplanalp

Scheiber

Moon

et al. 2000

European Journal of Endocrinology

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Estrogens possess strong antioxidant effects in vitro, but in vivo studies in humans have yielded conflicting results. Little is known regarding factors that mediate the antioxidant effect of estrogens in vivo. In this study the potential role of high density lipoprotein (HDL) was examined. The antioxidant effect of estradiol-17b (E2) added to low density lipoprotein (LDL) was lost after dialysis. In contrast, the antioxidant effect of E2 added to HDL was conserved after dialysis, suggesting that E2 was bound to HDL. Binding of E2 to LDL increased after esterification (especially to long chain fatty acids). In the presence of HDL, an increased amount of E2 was transferred to LDL. E2-17 ester was as potent as E2 in preventing LDL oxidation in vitro, but 3,17-diesters were not as effective (E2 = E2-17 ester > E2-3 ester > E2-3,17 diester). This was also supported by experiments which showed that estrogens with masked 3-OH groups were not effective as antioxidants. These studies provide evidence that HDL could facilitate the antioxidant effect of E2 through initial association, esterification and eventual transfer of E2 esters to LDL. Therefore it is critical that HDL peroxidation parameters be evaluated in subjects receiving estrogen replacement therapy.

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Section: Introductionmentioning

confidence: 99%

Evidence for the role of high density lipoproteins in mediating the antioxidant effect of estrogens

Abplanalp

Scheiber

Moon

et al. 2000

European Journal of Endocrinology

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“…Estrogen therapy is well known to result in favourable changes in plasma lipid profiles (for a review see ref. 11 ). In the present study, total Figure 4 Liver (A), heart (B), and adrenal glands (C), weight (WT) relative to 100 g of body weight (BW) in sham-operated rats (SHAM), ovariectomized rats with placebo replacement (OVX), and OVX rats with estrogen replacement (OVXE2) studied under sedentary (SED; solid, grey, or open bars) or trained (TR; hatched and crosshatched bars) conditions.…”

Section: Physical Training and Estrogen Replacementmentioning

confidence: 99%

“…Estrogen therapy is well known to reduce food intake, body weight and fat deposition 2 -4 and to result in favourable changes in plasma lipid profiles. 11 Estrogens are also known to induce adenohypophyseal hypertrophy. 12,13 The sparse existing studies on the interaction of exercise training and estrogen replacement have been mainly aimed at the prevention of bone loss.…”

Section: Introductionmentioning

confidence: 99%

Effects of physical training on body composition and organ weights in ovariectomized and hyperestrogenic rats

Shinoda

2002

Int J Obes

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OBJECTIVE:To investigate whether regular endurance-type exercise can benefit rats submitted to a model of ovariectomy (OVX)-induced obesity with or without estrogen replacement. SUBJECTS: OVX Sprague-Dawley rats were compared to an ovariectomized-estradiol-treated group (OVXE2) and a Shamoperated (Sham) group. Each of these groups were subdivided into a sedentary and a treadmill-trained (8 wk) group. DESIGN AND MEASUREMENTS: An experimental study in which various parameters, including fat depots, blood lipids and several organ weights were measured. RESULTS: Plasma levels of 17b-estradiol and uterus weights were significantly (P < 0.05) lower in OVX compared to Sham and significantly (P < 0.01) higher in OVXE2 (hyperestrogenic) compared to Sham rats. Body weights were significantly (P < 0.01) different among groups, in the following decreasing order: OVX, Sham and OVXE2. The average daily food intake and food efficiency were significantly (P < 0.01) increased in OVX compared to Sham, whereas estradiol treatment diminished this effect (P < 0.01). Exercise training did not alter any of the above-mentioned variables in any of the three estrogen groups. Mesenteric and subcutaneous fat weights were significantly (P < 0.01) increased by OVX. This increase was abolished by estrogen replacement or by exercise training. Exercise training also decreased fat weights in OVXE2 and Sham rats. OVX resulted in a decrease in the weights of several other tissues (femur, heart, lungs, liver and adrenal glands) while hyperestrogenic replacement resulted in an increase in weight of all measured tissues. Aside from fat depots, exercise training did not affect any of the tissue weights with the exception for an increase in the weight of the plantaris muscle and adrenal glands and a decrease in lung weight in all three estrogen groups. CONCLUSION: In OVX animals, exercise training may bring about positive changes in body composition (ie reduction in fat weights) despite an ovariectomy-induced increase in body weight.

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“…In addition, estrogen therapy is well known to reduce body weight and fat deposition and result in favorable changes in plasma lipid profiles. [42][43][44] Estrogen has been reported as a beneficial factor in preventing cardiovascular diseases, like atherosclerosis, by keeping cholesterol levels low in premenopausal women. Menopausal women lose this protection because of a dramatic decrease in estrogen levels as a result of natural atrophy of the ovaries.…”

Section: Discussionmentioning

confidence: 99%

Effects of Asparagus racemosus Root Extracts on Serum Lipid Profiles, Lipid Peroxidation and Superoxide Dismutase in Ovariectomized Rat

Taepongsorat¹,

Phadungkit²

2018

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Background: Once rats have been ovariectomized they have a high risk of cardiovascular disease due to changes in the blood cholesterol and lipid profile. Objective: To investigate the effects of Asparagus racemosus (AR) root extract on the serum lipid profiles, lipid peroxidation and antioxidant levels in ovariectomized rats. Methods: Twenty-five, two month-old female Wistar rats were randomly divided into five groups: SH, OVX,OEE, OAAR and OEAR. The daily doses of 500 mg/KgBW of the AR root extracts for five weeks.The levels of serum TG, TC, HDL, LDL, the liver, kidney and uterine tissue lipid peroxidation and SOD levels were determined. Results: Serum TC and LDL showed no significant differences in any groups. Serum TG of the OAAR and OEAR groups were not significantly different. The serum HDL of the OAAR and OEAR groups were significantly lower than the OEE group. The liver MDA levels of the OAAR and OEAR groups were significantly decreased compared with the OVX and OEE groups while the SOD level of the OAAR group was significantly increased. The MDA levels in the kidney and uterine of the treated group showed no significant difference. The SOD levels in the kidney of the treated group were not different but the SOD levels in uterine were significantly decreased. Conclusion: It can be believed that the lipid profiles were maybe regulated via estrogen.The AR extract has low effects on the lipid profiles at this dose and duration of treatment. The capacity of the extracts to decrease the MDA level and increase the SOD level in this study clearly reflected the antioxidant efficiency of these substances. or sam-roi-rak. The extracts of the roots of AR have in the last few years been determined to have a phytoestrogenic effect and help with neurodegenerative disorders, in addition to effects on antidiarrheal, antidyspepsia, adaptogenic, cardioprotective, antibacterial, immunoadjuvant and antitussive.5 There are two major forms in which the root extracts of AR have been used (methanolic and aqueous extracts) as tablets, powders in tablets or a syrup form. 6 In addition, there have been reports of activities related to immunostimulant, antihepatotoxic or antioxytocic. 5 In laboratory animals, there have been recent reports the extracts of AR roots have antioxidant and antidiarrheal effects. [7][8] In rats, the lipid peroxidation (malondialdehyde: MDA) decreased while there were increases in superoxide dismutase (SOD), catalase and ascorbic acid by the methanolic root extracts.

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Mechanisms of Cardioprotection by Estrogens

Cited by 92 publications

References 60 publications

Evidence for the role of high density lipoproteins in mediating the antioxidant effect of estrogens

Evidence for the role of high density lipoproteins in mediating the antioxidant effect of estrogens

Effects of physical training on body composition and organ weights in ovariectomized and hyperestrogenic rats

Effects of Asparagus racemosus Root Extracts on Serum Lipid Profiles, Lipid Peroxidation and Superoxide Dismutase in Ovariectomized Rat

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