Comparison of the antioxidant effects of equine estrogens, red wine components, vitamin E, and probucol on low-density lipoprotein oxidation in postmenopausal women
Bibliographic record
Abstract
OBJECTIVE: Oxidized low-density lipoprotein (LDL) seems to play an important role in the etiology of atherosclerosis. To further study this, we performed two studies: (1) we determined the ability of 10 estrogen components of the drug, conjugated equine estrogen (CEE), trans-resveratrol (t-resveratrol) and quercetin (red wine components), trolox (vitamin E analog), and probucol (a serum cholesterol-lowering drug) to delay or prevent the oxidation of plasma LDL isolated from untreated postmenopausal women, and (2) we assessed the effect of long-term (>1 year) estrogen replacement therapy and hormone replacement therapy on LDL oxidation by ex vivo methods. DESIGN: For the in vivo study, three groups of postmenopausal women were selected based on whether they were on long-term CEE therapy (group A: 0.625 mg CEE; n = 21), on combination CEE plus progestogen therapy (group B: 0.625 mg CEE + 5.0 mg medroxyprogesterone acetate, 10 days; n = 20), or not on any hormone therapy (group C; n = 37). For the in vitro study, only LDL samples obtained from group C were used. The kinetics of LDL oxidation were measured by continuously monitoring the formation of conjugated dienes followed by determination of the lag time. RESULTS: All compounds tested protected the LDL from oxidative damage. The relative antioxidant potency of estrogen components was generally greater than that of the other compounds. The minimum dose (nmoles) required to double the lag time from the control lag time of 57 +/- 2 min was 0.47 for 17beta-dihydroequilenin, 17alpha-dihydroequilenin, Delta 8 -estrone; 0.6 to 0.7 for Delta 8 -17beta-estradiol, equilenin, and quercetin; 0.9 for 17beta-dihydroequilin and 17alpha-dihydroequilin; 1.3 for equilin, estrone, 17beta-estradiol, 17alpha-estradiol; 1.4 for trolox; 1.9 for probucol; and 3.0 for t-resveratrol. The data from the in vivo study indicate that after long-term estrogen replacement therapy (group A) and hormone replacement therapy (group B), the LDL was significantly ( p < 0.01) protected (higher lag time) against oxidation compared with the control (group C). There was no difference between groups A and B. CONCLUSIONS: The oxidation of LDL isolated from postmenopausal women is inhibited differentially by various estrogens and other antioxidants. The unique ring B unsaturated estrogen components of CEE were the most potent, and t-resveratrol, the red wine component, was the least potent. Long-term CEE or CEE + medroxyprogesterone acetate administration to postmenopausal women protects the LDL against oxidation to the same extent. These combined data support the hypothesis that some of the cardioprotective benefits associated with CEE therapy and perhaps red wine consumption may be due to the ability of their components to protect LDL against oxidative modifications.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.002 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".