ABSTRACT
The effects of estrogen and progestins on the vascular wall have drawn major medical attention, and significant controversy over various studies has been developed. Several experimental and observational studies have shown cardioprotective effects; however, prospective randomized trials showed an increase in cardiovascular events in postmenopausal women on estrogen/ medroxyprogesterone acetate treatment. The most significant parameter for cardiovascular benefit of estrogen seems to be the interval since the onset of menopause. In the early postmenopausal years, estrogen has beneficial effects on the vascular wall by inhibition of atherosclerosis progression, whereas in the late postmenopause, adverse effects like upregulation of the plaque inflammatory processes and plaque instability may develop. The effects of progestins on the cardiovascular system are not as clear and may differ according to the choice of progestins that is used. The aim of this review is to summarize the effects of estrogen and progestins on the vascular wall and their clinical implications.
Subject(s)
Coronary Artery Disease/prevention & control , Estrogen Replacement Therapy/methods , Nitric Oxide/blood , Age Factors , Coronary Artery Disease/blood , Coronary Artery Disease/pathology , Coronary Vessels/drug effects , Coronary Vessels/pathology , Drug Administration Schedule , Endothelium, Vascular/drug effects , Endothelium, Vascular/pathology , Female , Humans , PostmenopauseABSTRACT
OBJECTIVES: The aim of this study is to evaluate oxidative protein damage (OPD) by investigating protein carbonyl (PCO) and nitrotyrosine (NT) levels, oxidative stress by total thiol (T-SH), erythrocyte glutathione (GSH) and nitric oxide (NO) levels in women receiving hormone replacement therapy (HRT). MATERIALS AND METHODS: To examine the influence of oxidative stress on OPD, we studied 12 postmenopausal women who had received HRT for 6 months, and 13 postmenopausal women who did not receive HRT, as the control group. All subjects were non-smokers. Blood samples were drawn in the fasting state and processed within 1 h of collection. For NT and NO, serum samples were stored at -70 degrees C until analysis; all other parameters were determined on the same day of collection. RESULTS: After 6 months, plasma PCO and T-SH levels were decreased, GSH and NO levels were increased, and NT levels were not changed in 12 postmenopausal women receiving HRT. Except the NT levels, the rest of the parameters did not significantly change in the control group. Interestingly, mean NT levels in the control group increased significantly. CONCLUSIONS: A crucial part of the protective effect of HRT on the cardiovascular system arises secondary to the interaction between estrogen and vessel wall. Our results suggest that an important component of the mechanism underlying this interaction may depend on estrogen's antioxidant effect and its preventive role in OPD.
Subject(s)
Estrogen Replacement Therapy , Oxidative Stress , Postmenopause , Tyrosine/analogs & derivatives , Blood Proteins/metabolism , Case-Control Studies , Cholesterol , Cholesterol, HDL , Cholesterol, LDL , Estrogens, Conjugated (USP)/administration & dosage , Female , Glutathione/blood , Humans , Medroxyprogesterone Acetate/administration & dosage , Middle Aged , Nitric Oxide/blood , Sulfhydryl Compounds/blood , Triglycerides , Tyrosine/bloodABSTRACT
OBJECTIVES: The aim of this study is to evaluate the relationship between plasma nitric oxide (NO) and beta-endorphin levels in women using hormone replacement therapy (HRT) for 12 months. MATERIAL AND METHODS: Our study group was composed of 55 patients who were in at least their second postmenopausal year. Of the 55 patients, 25 were in the control group. All 30 women in the study group received 2 mg 17beta-estradiol + 1 mg norethisterone acetate tablets daily for 12 months. Plasma NO and beta-endorphin levels were measured both before and after the study period and possible relationships were analyzed. RESULTS: There was a significant increase in both beta-endorphin (p = 0.0001, 10.93 +/- 2.25 vs. 14.85 +/- 2.49) and NO (p = 0.0001, 19.79 +/- 4.01 vs. 27.83 +/- 10.27) levels measured after the study in the HRT group. A correlation was seen between the increments in beta-endorphin and NO levels in the HRT group. CONCLUSION: Continuous combined HRT raises both plasma NO and beta-endorphin levels and a close relationship was found between the two molecules after therapy. We postulate that the increment in these molecules may explain some of the beneficial effects of HRT on cognitive function and mood.
