Estrogen/progesterone replacement versus pravastatin and their sequential association in hypercholesterolemic postmenopausal women

Objectives: The objectives of this study were to assess serum lipid changes in response to an oral estrogen combined with progesterone (Group A) as compared with pravastatin (Group B) and to evaluate the additive effects of the sequential addition of statin to hormonal replacement therapy (HRT) and of HRT to statin. Methods: Thirty-seven of 63 hypercholesterolemic menopausal women initially submitted to a 4-month diet were randomised to oral conjugated estrogens (0.625 mg)/micronised progesterone (200 mg) or to pravastatin (40 mg). After 6 months, each group received both medications for another 6 months. Results: Nineteen percent of women corrected their lipids below decision levels with diet alone. Low density lipoprotein-cholesterol (LDL-C) decreased by 8±5% with HRT and by 26±3% (P<0.001) with the statin. These single medications increased high density lipoprotein-cholesterol (HDL-C) by 13±5% (P<0.01) and 11±7%, respectively. Combined interventions produced cumulative LDL-C reductions of 40±2 and 42±3% (P<0.001) and additive HDL-C augmentations of 16±4 and 23±5% (P<0.01) with proportional changes in apolipoprotein (Apo)B-100 and ApoA-1. These combined effects brought the atherogenic index (C/HDL-C) for Groups A and B, respectively, from a moderate (5.18±0.25 and 5.87±0.18) to a reduced (3.35±0.20 and 3.52±0.19) risk category. Triglycerides (TG) which were increased by HRT and decreased by the statin returned to baseline during combined treatments. No changes in diet, physical activity or anthropomorphometric measurements explained the lipid modifications. Conclusions: In menopausal patients with elevated C not responding to diet, pravastatin was most effective to decrease LDL-C, and oral estrogen–micronised progesterone most effective to increase HDL-C. Marked reduction of the atherogenic index is achieved by sequential combinations of medications resulting from beneficial cumulative effects on both C-LDL and C-HDL.     

Plasma leptin levels in obese and non-obese postmenopausal women before and after hormone replacement therapy

Objective: the aim of this study was to investigate the effect of hormone replacement therapy (HRT) on plasma leptin levels in postmenopausal women, and the relationship between the plasma leptin levels and obesity. Methods: premenopausal women with normal cycles (n=30; mean ages, 35.4±8.3 years) and postmenopausal women (n=45; mean ages, 49.5±4.7 years) were randomly selected. Women were classified as obese (BMI>27 kg/m²) and as non-obese (BMI<27 kg/m²). Blood samples were obtained from the premenopausal women at the beginning of cycle, and from the postmenopausal women before and 6 months after HRT. Plasma leptin levels were measured by radioimmunassay. Results: plasma leptin levels were significantly higher in premenopausal women than in postmenopausal women (18.60±5.0; 3.67±2.44 ng/ml, respectively, P<0.001). Obese premenopausal women (n=15) had significantly higher plasma leptin levels (24. 60±7.81 ng/ml) in comparison with the levels of the non-obese premenopausal women (n=15; 12.50±4. 63 ng/ml) (P<0.001). Although there was no significant difference in the plasma leptin levels between obese (n=25) and non-obese (n=20) postmenopausal women before HRT, plasma leptin levels were significantly elevated in both obese and non-obese postmenopausal women after HRT (P<0.001), and the obese women had significantly higher plasma leptin levels than the non-obese (29.05±10.53; 14.78±6.76 ng/ml, respectively, P<0.001). Conclusion: HRT is effective in the elevation of the plasma leptin levels in postmenopausal women, and in obese women the increase of the plasma leptin levels are more marked than the non-obese women after HRT.     

Change in body weight after hormone replacement therapy in postmenopausal women is dependent on basal circulating leptin

Objective: To address the effect of leptin in the modulation of change in body weight after hormone replacement therapy (HRT), we prospectively examined the responses of body weight and serum leptin after estrogen–progestin replacement in postmenopausal women. Patients: Subjects consisted of 63 postmenopausal women aged 54–82 years on HRT for osteoporosis. Design: Thirty three of the subjects received 0.3 mg of conjugated equine estrogen (CEE) (group 1) while 30 were on 0.625 mg of CEE daily (group 2). All subjects also took 5 mg of medrogestone acetate and 750 mg elemental calcium supplement daily. Measurements: Fasting serum leptin was measured by RIA at baseline, 1 and 3 months after treatment. Data were expressed as mean±S.E.M. Results: Serum leptin was highly related to body weight both at baseline (r=0.40, P<0.001) and after 3 months of HRT (r=0.42, P<0.001). When divided the subjects into three equal groups according to baseline leptin levels, it was found that serum leptin significantly decreased in subjects with high baseline leptin at 3 months (−9.4±5.7%, P<0.05) while it increased in subjects whose baseline leptin levels were in the lowest tertile at 1 month (33.2±8.3%, P<0.001) and 3 month (27.8±8.3%, P<0.01). In regards to body weight, those with leptin in the highest tertile demonstrated a reduction of body weight at 3 (−1.9±0.6%, P<0.05) and 12 months (−3.2±0.5%, P<0.05) after HRT while those whose serum leptin levels were in the lowest and middle tertiles did not demonstrate change in body weight. By repeated measured analysis of variance, it was found that the decrease in body weight in subjects with high serum leptin was independent of the doses of estrogen. Conclusion: Postmenopausal hormone replacement does not cause weight gain. However, it results in a small reduction in body weight particularly in subjects with higher basal leptin concentrations.     

Effects of estrogen on susceptibility to oxidation of low-density and high-density lipoprotein in postmenopausal women

Objective: To investigate the effects of estrogen on the susceptibility to oxidation of low-density lipoprotein (LDL) and high-density lipoprotein (HDL) in postmenopausal women. Methods: A total of 23 postmenopausal women were treated with 0.625 mg of conjugated equine estrogen daily for 3 months. Blood samples were obtained before and after therapy. Plasma levels of total cholesterol and triglyceride and the concentrations of cholesterol, triglyceride, phospholipid in LDL and HDL were determined enzymatically and the levels of apolipoprotein A-I, A-II in HDL and apolipoprotein B in LDL were measured by turbidimetric immunoassay. The isolated LDL and HDL were incubated at 37°C for 24 h with CuSO₄ 5 μmol/l and the lipid peroxide concentration of LDL and HDL was measured. Results: Estrogen significantly reduced the plasma level of total cholesterol and significantly increased the plasma level of triglyceride. The LDL concentrations of cholesterol, phospholipid and apolipoprotein B were significantly decreased following estrogen therapy. The triglyceride level of LDL did not change significantly. The HDL concentrations of cholesterol, triglyceride, phospholipid and apolipoprotein A-I and A-II were all significantly elevated after estrogen therapy. Estrogen significantly inhibited the peroxidation of LDL at 50–2000 μg of LDL protein (14.17±4.17–11.49±1.42 nmol/200 μg of LDL protein, P<0.001) and of HDL (4.49±1.74–3.37±1.24 nmol/200 μg of HDL protein, P<0.03) induced by their incubation in the presence of CuSO₄. Conclusions: Estrogen inhibited the susceptibility of LDL and HDL to oxidative modification and favorably affected lipid metabolism by reducing the number of LDL particles and increasing the number of HDL particles in plasma that were resistant to oxidation.     

Effects of bezafibrate and simvastatin on plasma lipoproteins in hypercholesterolemia resistant to hormone replacement therapy

Objectives: Estrogen replacement therapy has favorable effects on serum lipoprotein levels in postmenopausal women with hypercholesterolemia. However, there are some patients who fail to respond to hormone replacement therapy (HRT) to lower the serum cholesterol level. In these cases, a conventional lipid-lowering therapy will be applied in addition to HRT, while the effects of these drugs are not well understood. In this study, we studied the effects of simvastatin and bezafibrate administered in addition to HRT. Methods: Patients who were hypercholesterolemic even after HRT were randomly assigned to three treatment groups: HRT only (control group, n=10), HRT+simvastatin (10 mg/day, n=10), or HRT+bezafibrate (400 mg/day, n=10). Serum lipids and lipoprotein levels were measured throughout 12 weeks. Results: The serum triglyceride levels were decreased by 24±28 and 38±13% in the HRT+simvastatin and HRT+bezafibrate groups, respectively. HRT+simvastatin decreased the total cholesterol (21±10%) and low-density lipoprotein cholesterol (28±12%) levels without affecting the high-density lipoprotein cholesterol (HDL-C) level, while HRT+bezafibrate increased the HDL-C level (12±11%). Conclusions: Treatment with simvastatin or bezafibrate in addition to HRT should be considered in cases of postmenopausal hypercholesterolemia in which HRT alone fails to lower the serum lipoprotein levels.     

Effects of menopause and hormone replacement therapy on plasma lipids, lipoproteins and LDL-receptor activity

A cross-sectional study of ninety six women was conducted to examine the effect of menopause and hormone replacement therapy (HRT) on plasma lipids, lipoproteins and oxidation of low density lipoproteins. The sample consisted of 26 premenopausal women, 26 postmenopausal women taking no replacement hormones and 43 postmenopausal women on hormone replacement therapy. Postmenopausal women not taking replacement hormones had significantly higher plasma cholesterol, low density lipoprotein (LDL) cholesterol and lipoprotein[a] (Lp[a]) levels compared to premenopausal women or postmenopausal women on HRT [6.00±0.15, 5.36±0.17 (P<0.01), 5.63±0.13 (P<0.05) mmol/l, respectively for total cholesterol; 4.13±0.15, 3.64±0.15 (P<0.05), 3.82±0.12 (P<0.05) mmol/l, respectively for LDL-cholesterol; 48.19±9.90, 26.59±5.53 (P<0.03), 25.12±4.62 (P<0.03) mg/dl, respectively for Lp[a]]. The differences in LDL cholesterol concentrations were inversely related to changes in LDL receptor activity (r=−0.27, P<0.01). HRT use was found to be associated with a significantly smaller LDL particle size. Plasma triglyceride was significantly higher in women on HRT (1.16±0.07 mmol/l) than in the premenopausal group (0.96±0.07) or postmenopausal group not using HRT (0.87±0.06). There were no differences in LDL oxidation between the groups when LDL was oxidised in the presence of copper. Nor was there any difference in the uptake of copper-oxidised or macrophage-modified LDL into J774 macrophages. These results confirm the effect of menopause and exogenous hormones on plasma lipids and lipoproteins, and suggest that HRT modifies the activity of the LDL receptor. Hormone replacement did not appear to protect LDL from oxidation.     

Progestins used in hormonal replacement therapy display different effects in coronary arteries from New Zealand white rabbits

Objectives: The aim of this study was in an animal model to assess the vascular effects of different progestins commonly used in hormonal replacement treatment. Methods: Fifty-six non-atherosclerotic, ovariectomized New Zealand white rabbits were randomized into seven groups: (1) medroxyprogesterone acetate (MPA), (2) norethisterone acetate (NETA), (3) conjugated equine estrogens (CEE), (4) 17-β-estradiol (E2), (5) MPA+CEE, (6) NETA+E2, (7) or placebo (n=8) and given hormonal treatment through the diet for 4 weeks. Ring segments from the left proximal coronary artery and from the distal part of the left anterior descending coronary artery were microdissected and mounted for isometric tension recordings in a myograph. The vasoconstrictory responses induced by potassium, endothelin-1, calcium and N_w-nitro- -arginine methyl ester, and the vasodilatory response induced by acetylcholine and sodiumnitroprusside were investigated. The maximum contraction/relaxation (E_max) and the concentration required to induce half the maximum response (EC₅₀) were determined. EC₅₀ values were expressed as the negative logarithm to the molar concentration, pD₂=−log EC₅₀. Results: Treatment with MPA alone caused when compared to treatment with NETA an increase in tension development in the distal coronary artery after the addition of potassium (6.36±0.36 versus 4.31±0.42 P<0.005) (single dose response, mN/mm, mean±S.E.M.) and endothelin-1 (9.41±0.82 versus 6.43±0.73 P<0.05) (E_max, mN/mm, mean±S.E.M.). Treatment with MPA compared to placebo caused an endothelin-1 induced increase of E_max in the distal coronary artery (9.21±0.87 versus 6.51± 0.65 P<0.05) and a calcium induced increase of pD₂ in both coronary arteries (2.98±0.19 versus 2.42±0.12 P<0.05, proximal coronary artery) (3.26±0.09 versus 2.9±0.1 P<0.05, distal coronary artery) (pD₂, mean±S.E.M.). Treatment with NETA compared to placebo in the proximal coronary artery, after the addition of sodiumnitroprusside caused a decrease of pD₂ (5.33±0.19 versus 5.94±0.13 P<0.05). Treatment with E2 compared to treatment with CEE in the proximal coronary artery caused a decrease of pD₂ after the addition of sodiumnitroprusside (5.00±0.16 versus 5.77±0.28 P<0.05). No significant differences were found between MPA+CEE and NETA+E2. Conclusion: Treatment with MPA alone seems to enhance the contractile response to potassium and endothelin-1 in the distal coronary artery compared to NETA, indicating that different progestins used in hormonal replacement treatment may display different effects on contractile functions of coronary arteries.     

Effect of menopause on low-density lipoprotein oxidation: is oestrogen an important determinant?

Objectives: Significantly increased risk for developing cardiovascular disease in post-menopausal women is linked with the fall of oestrogen. Although supraphysiological levels of oestrogen may inhibit oxygen free radical mediated low-density lipoprotein (LDL) oxidation, the effect of physiological level of oestrogen on LDL oxidation is unknown. Methods: The present study compared oxidizability of LDL in healthy pre- and post-menopausal women by using a commonly employed copper ion-dependent method. Results: Pre-menopausal women (n=20, mean age 27) had significantly higher serum oestradiol level (576±109 pmol/l) in comparison to post-menopausal women (n=23, mean age 51, oestradiol 64±18 pmol/l, P<0.001). The oxidation of LDL in two groups was not different by measuring either the lag phase of conjugated dienes formation (54±12 vs. 55±14 min, P>0.05) or the generation of thiobarbituric acid reactive substances over 4 h of oxidation. The major lipid soluble antioxidant in LDL, vitamin E (determined as -tocopherol) is similar in two groups (2.34±0.48 vs. 2.40±0.56 nmol/mg LDL, pre- and post-menopausal subjects, respectively, P>0.05). Linear regression analysis found a weak but significant correlation between LDL vitamin E level and oxidizability of LDL in both groups but did not show effect of serum oestradiol levels. Conclusion: The results suggest that physiological levels of oestrogen may not be able to affect in vitro LDL oxidation.     

Value of C-reactive protein levels and IL-6 in predicting events levels in women at increased cardiovascular risk

Background: Elevated C-reactive protein (CRP) levels due to of heightened vascular inflammatory state in vascular conditions are often associated with elevated interleukin-6 (IL-6) levels since during inflammation CRP production in the liver is induced by IL-6. It has been suggested that CRP may be a predictors of unfavourable outcome in postmenopausal women (PMW) receiving hormone replacement therapy. Because of the possible metabolic effect of hormone replacement therapy (HRT) on CRP, the relative predictive importance of CRP and IL-6 levels in PMW receiving HRT remains to be elucidated. Methods: We measured plasma levels of CRP and IL-6 levels in 346 consecutive PMW (mean age 66±9 years) with cardiovascular risk >20 in 10 years followed during a 36 month period. Women underwent measurement of inflammatory cytokines at baseline and were allocated to two groups according to the willingness to take hormone replacement therapy. All women underwent a further measurement of CRP and IL-6 at 3 and 6 months. Health status was assessed by out patient visits and hospital charts. Results: During 1 year follow up, three patient died, four had a major cardiovascular event, three had a unstable angina, two had a transient ischemic attack and two patients underwent PTCA. PMW with events had higher CRP levels compared with patients with no events (1.94±0.61 versus 1.43±0.21, P<0.05) but still within the limits of normal. Also baseline IL-6 plasma levels were significantly higher in PMW with events than in those without events (0.87±0.23 versus 0.54±0.18, P<0.05). The increase in CRP and IL-6 with HRT was significantly higher in patients with events than in those with no events (CRP: 81±12% versus 76±21%, P<0.05; IL-6 9±3% versus −14±7%, P<0.05). In a stepwise multivariate analysis, IL-6 levels resulted a stronger predictor of outcome than CRP. CRP levels were predictors of future events only after removal of IL-6 levels and presence of cardiovascular symptoms from the analysis. CRP levels were associated with an unfavourable outcome only when IL-6 levels were also elevated. The increase in CRP with HRT during follow up was not associated to an increased event rate. Conclusion: Our study showed that CRP levels are increased in PMW receiving HRT. Elevated IL-6 levels may identify those PMW at increased 1 year risk. CRP levels predict events only when they are coupled with elevated IL-6 levels.     

The age and symptomatology of natural menopause among United Arab Emirates women

Objectives: To determine the median age of natural menopause in United Arab Emirates women, the factors affecting that age and the prevalence of climacteric symptoms amongst those women. Methods: A population-based survey was conducted on a community sample of United Arab Emirates women who had had natural menopause defined as cessation of menstruation for at least 6 months at the end of reproductive years. A total of 742 women aged 40 years and above were recruited from both urban and rural areas of the country using the multi-stage stratified cluster sampling technique. Data were collected using a structured questionnaire and face to face interviews and included a number of familial, reproductive and life-style variables. Results: The median age of the menopause in the United Arab Emirates is 48 years (mean=47.3±3.29, range 40–59). This is significantly lower than the median age reported from the West (50.3 years). The subject median age of the menopause was significantly related to that of the mother (P<0.001), older sister (P<0.001), parity (P<0.0001) and the previous use of oral contraceptive pills for more than 1 year (P<0.001). Hot flushes were the commonest feature of the menopause occurring in 45% of women. Conclusion: The age of natural menopause in United Arab Emirates women, as in other developing countries, is less than in Western women and may be influenced by genetic factors, parity and previous use of oral contraceptives. Climacteric symptomatology, however, is similar in the different patient groups.     

Bone turnover and its relationship with bone mineral density in pre- and postmenopausal women with or without fractures

Objective: This work was carried out in order to investigate possible relationships between bone turnover rate, as evaluated by bone biomarkers and skeletal mass, as evaluated by bone mineral density (BMD). Method: Fifty-eight normal women and 30 female patients with osteoporotic fractures were enrolled. Three groups were defined: (1) fertile subjects (n=24), mean age 33.7±8.1 years; (2) postmenopausal women (n=32, including 11 patients with fractures) whose BMD values, in terms of T score, were less than −2.5 S.D. below the young adult mean obtained in our laboratory (mean age 61.7±7.9 years; and years since menopause (ysm), 12.6±8.3); (3) postmenopausal women (n=32, including 19 patients with fractures) whose BMD values in terms of T score, were below −2.5 S.D. (mean age 62.9±8.6 years; and ysm 15.9±9.0). Groups II and III characterised, by inclusion criteria, by significant different mean BMD values, were similar as far as chronological and menopausal age were considered. Metabolic tests included a short urine collection to determine calcium, hydroxyproline, cross-linked N-telopeptides of type I collagen (NTx) and creatinine (Cr); half-way through this collection, a blood sample was taken for the measurement of total alkaline phosphatase activity (ALP) and tartrate-resistant acid phosphatase activity (TRAP). BMD at lumbar spine was evaluated. Results: There were significant differences amongst the three groups in mean ALP (P<0.001, by analysis of variance) TRAP (P<0.006) and NTx/Cr (P<0.001) values, but not as far as mean values of calcium/Cr or hydroxyproline/Cr ratios were concerned. Considering the group as a whole, there were significant inverse correlations between NTx/Cr, ALP, TRAP and BMD controlling for both age (r=−0.392, P<0.001; r=−0.447, P<0.001 and r=−0.327, P<0.002, respectively) and ysm (r=−0.374, P<0.001; r=−0.474, P<0.001 and r=−0.333, P<0.002). Conclusions: Our results indicate, that, even after controlling for both ageing and oestrogen status, there is an inverse relationship between bone mass (that at a given time represents the balance of all previous metabolic events) and a biochemical marker (which reflects bone turnover at the time of examination). These findings are in line with the belief that increased bone turnover should be regarded as a risk factor for osteoporosis. Furthermore, our results indicate that, unless there is no increase of hepatic isozyme, total ALP still maintains a possible role as a first analysis to evaluate bone turnover before requesting markers with greater specificity, sensitivity but also more expensive and whose analysis is sometimes time-consuming.     

Increased (E)-4-hydroxy-2-nonenal and asymmetric dimethylarginine concentrations and decreased nitric oxide concentrations in the plasma of patients with major depression

Background: (E)-4-Hydroxy-2-nonenal (HNE) is a highly electrophilic end-product of lipid peroxidation. Asymmetric dimethylarginine (ADMA) is an endogenous inhibitor of endothelial nitric oxide synthase (NOS). ADMA is metabolised by dimethylarginine dimethylaminohydrolase (DDAH). DDAH contains a nucleophilic cysteine residue in its active site. There is an increase in lipid peroxidation in major depression. Major depression is associated with the development of coronary heart disease (CHD) and greatly increases morbidity and mortality. There is an increase in circulating ADMA in CHD and vascular risk factors. Objectives: To determine plasma HNE, ADME and nitric oxide (NO) concentrations in patients with major depression compared to normal volunteers and to examine the effect of HNE on ADMA formation and DDAH activity in cultured endothelial cells. Methods: The study was conducted in 25 patients with major depression (DSM-IV criteria) and 25 healthy control subjects. Plasma concentrations of HNE were determined as the O-pentafluorylbenzyl oxime using capillary column GC–MS and deuterated HNE as the internal standard; ADME by LC–MS–MS using ¹³C⁶- -arginine as the internal standard; and NO by GC–MS following reduction to nitrate and nitrite and derivatisation to the pentafluorobenzyl derivative using [¹⁵N]nitrate and [¹⁵N]nitrite as the internal standards. Human umbilical vein endothelial cells were incubated in serum-free medium in the presence of HNE. The concentration of ADMA in the medium was determined by LC–MS–MS. DDAH activity was determined by measuring -citrulline in endothelial cell lysates using LC–MS. Results: There was a significant increase in the plasma concentration of HNE (P<0.0001) and ADMA (P<0.0002) in patients with major depression. There was a significant decrease in the plasma concentration of NO (P<0.0001). A significant positive correlation was found between the plasma concentrations of HNE and ADMA (r=0.63, P<0.0001). A significant negative correlation was detected between the plasma concentrations of ADMA and NO (r=−0.595, P<0.0001). HNE significantly increased ADMA formation (P<0.0001) and significantly decreased DDAH activity (P<0.0001) in cultured endothelial cells. The effects of HNE on DDAH activity were significantly attenuated by the addition of glutathione (P<0.0001). Limitations: No allowance was made for the phase of the menstrual cycle which could influence plasma nitric oxide concentrations. Conclusions: There is an increase in circulating HNE in major depression. HNE inactivates the cysteine residue in the active site of endothelial DDAH leading to the accumulation of ADMA in the circulation. The ADMA then decreases the production of eNOS. This could reduce the amount of NO diffusing from cerebral blood vessels to nearby neurons and influence the release of neurotransmitters. ADMA also constricts cerebral blood vessels and may contribute to the decreased regional perfusion in major depression. The accumulation of ADMA could explain the increased risk of CHD in major depression. The preservation of DDAH activity and the reduction of ADMA accumulation may represent a novel therapeutic approach to the treatment of major depression.     

Triglyceride and lipoprotein (a) are markers of coronary artery disease severity among postmenopausal women

Objective: After menopause, some women manifest coronary artery disease (CAD) with highly variable angiographic severity. For these women, postmenopausal appearing of some CAD risk factors may have differently influenced the CAD risk and severity. In this study, we attempt to unravel differences in the frequency or intensity of CAD risk factors among postmenopausal women with different angiographic severity. Methods: We studied 182 postmenopausal women (64±6 years) who underwent coronary angiography to investigate thoracic pain. Subjects with no detectable coronary lesions at angiography were recruited to the non-obstructive group and patients with CAD were grouped in one-vessel or multi-vessel groups. We compared clinical variables as the body mass index (BMI), age at menopause, age, hypertension, diabetes and cigarette smoking, and lipid measurements as plasma levels of total cholesterol, triglyceride, low-density lipoprotein cholesterol, very low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, apolipoprotein (apo) A1, apo B and lipoprotein(a) (Lp(a)). Results: Comparing to the non-obstructive group, Lp(a) was twofold higher in the one-vessel group and threefold higher in the multi-vessel group and triglycerides were 34% higher in the one-vessel group and 50% higher in the multi-vessel group. No further difference was found among the three groups. After multivariate logistic regression analysis, triglyceride (odds ratio: 1.01; P=0.0013) and Lp(a) (odds ratio: 1.006; P<0.0001) were independently indicative of the presence of obstructive CAD. Conclusion: We found that both Lp(a) and triglycerides constitute useful markers of CAD severity among postmenopausal women.     

Bone density patterns after normal and premature menopause

Objectives: The investigation of the effect of time and type of menopause on bone mineral density (BMD) at different ages. Methods: Five hundred and fourteen women, who had never received any hormonal substitution were studied in a cross-sectional design: 177 with normal (NMP), 210 with surgical (SUMP) and 127 with premature natural (EMP) menopause. Age at menopause was 49.1±3.9, 38.3±4.7 and 38.1±4.2 years (mean±1 S.D.), respectively. BMD was measured at L2–L4 vertebrae and proximal femur by the DEXA method. Results: EMP women presented significantly lower vertebral BMD than NMP women in the 45–55-years segments (P<0.001), but did not differ from SUMP women. This group exhibited lower vertebral BMD than NMP between 45 and 50 years (P<0.001). Regarding femoral neck, EMP women exhibited lower values than SUMP in the 45–50 and 55–65 age segments (P<0.001) whereas SUMP women presented significantly higher BMD values than NMP women after 55 years of age (P<0.001). The percentages of women with vertebral BMD (T-score values) in the osteoporotic range were significantly greater in EMP compared with either NMP or SUMP groups (both P<0.001) whereas in femoral neck lower in SUMP than the other two categories. Conclusions: Women with either natural or surgical premature menopause exhibit lower BMD of trabecular bone compared with normal menopause women at the age segments 45–55 and 45–50, respectively. However, surgical menopause women exceed normal menopause women in their mixed bone BMD values after 60 years as well as premature natural menopause women at almost all age segments.     

Anti-ischemic effect of chronic oestrogen replacement therapy alone or in combination with medroxyprogesterone acetate in different replacement schemes

Background: Oestrogen replacement therapy in postmenopausal women has a protective effect upon the cardiovascular system and improves exercise-induced myocardial ischemia. Although in hormone replacement schemes progestins are required to reduce the likelihood of uterine malignancies, little is known on the cardiovascular effect of progestins. The purpose of this study was to evaluate the effect of oestrogen replacement alone and two different estrogen–progestin replacement therapy schemes upon exercise induced myocardial ischemia. Material and method: The study population included 18 female menopausal patients with coronary artery disease. After a baseline exercise test patients received conjugated equine estrogens (CEE) 0.625 mg alone for 30 days when they underwent a second exercise test and were randomized to receive in a cross-over design medroxyprogesterone acetate (MPA) either in continuous combined therapy (2.5 mg/daily) for 28 days or in cyclical therapy (10 mg o.d. from day 16 to day 28). Results: After CEE alone two patients with a previously positive exercise test showed a negative exercise test. CEE increased time to 1 mm ST compared to baseline (352±185 vs 265±133 s, P<0.01). In the 2 pts in whom the exercise test was negative after CEE the test remained negative during continuous combined MPA therapy while become positive during cyclical MPA. CEE+continuous combined MPA increased both time to 1 mm ST and exercise time compared to baseline (386±165 vs 265±133 s, P<0.01 and 545±198 vs 465±186 s, P<0.05, respectively). No difference was found between baseline and CEE+cyclical MPA in either time to 1 mm ST or exercise time (268±164 vs 265±133 s, P=NS and 455±223 vs 465±186 s, P=NS, respectively). Conclusion: Continuous combined therapy with CEE+MPA improves exercise-induced myocardial ischemia in female patients with coronary artery disease while the beneficial effect of CEE is reduced by cyclical therapy.     

Glutamate transport in rat cerebellar granule cells is impaired by inorganic epileptogenic agents

There is evidence that extracellular glutamate levels are elevated in certain brain regions immediately prior to and during induction and propagation of seizures. There appears to be a correlation between the capacity of removing released glutamate and the genesis of epileptiform activity. Some models make use of metals, such as Co²⁺ and Ni²⁺, to induce epilepsy. We used patch-clamp recordings to measure the electrogenic glutamate transport in neuronal cells. The present results indicate that Co²⁺ (1 mM) and Ni²⁺ (5 mM) blocked glutamate transport by 17.6±3.9% (n=5, P<0.05) and by 31.8±6.2% (n=7, P<0.05), respectively. Ni²⁺ inhibited glutamate uptake in a dose-dependent manner. The IC₅₀ value obtained was 66.6 μM and the maximum inhibition was 40%. We conclude that one mechanism that may explain the seizures induced by exposure to those divalent cations is inhibition of the glutamate transporter.     

Comparison of the long-term effects of oral estriol with the effects of conjugated estrogen on serum lipid profile in early menopausal women

Objective: We investigated the long-term effects of oral estriol (E₃) on serum levels of total cholesterol (t-Cho), high-density lipoprotein cholesterol (HDL-Cho), low-density lipoprotein cholesterol (LDL-Cho), and triglycerides in early menopausal women. Methods: We studied 67 healthy early menopausal women who were treated for 48 months with 2.0 mg of E₃ plus 2.5 mg of medroxyprogesterone acetate daily (E₃ group, n=21), 0.625 mg of conjugated estrogen plus 2.5 mg of medroxyprogesterone acetate daily (CE group, n=19), or 1.0 μg of 1-hydroxyvitamin D₃ daily or 1.8 g of calcium lactate containing 250 mg of elemental calcium daily (control group, n=27). The serum levels of t-Cho, HDL-Cho, LDL-Cho, and triglycerides were evaluated at baseline and every 6 months. Results: After 48 months of treatment, the t-Cho decreased significantly by 4.3±2.1% (mean±SE) from baseline in the E₃ group, did not change in the CE group (−1.9±2.1%), and significantly increased (5.4±3.4%) in the control group. The HDL-Cho significantly increased in the CE group (10.7±2.4%), but not in the E₃ group (3.8±3.3%) or in the control group (−3.6±3.0%). The LDL-Cho significantly decreased in the CE group (−11.4±4.0%), did not change in the E₃ group (−5.2±3.6%), and significantly increased in the control group (11.8±6.3%). The triglyceride level decreased significantly in the E₃ group (−6.7±4.9%), whereas it significantly increased in the CE group (17.6±11.4%), and did not change in the control group (6.1±6.4%). Conclusions: Oral E₃ prevented a postmenopausal rise in the t-Cho. Oral estriol did not induce the hypertriglyceridemia that was seen after treatment with conjugated estrogen. Oral E₃ may be a useful alternative therapy in women with hypertriglyceridemia and in women who are reluctant to continue conventional hormone replacement therapy because of uterine bleeding.     

Relaxation responses of aortic rings from salt-loaded high calcium fed rats to potassium chloride, calcium chloride and magnesium sulphate

The relaxation responses of aortic rings of rats fed either normal rat feed, 8% salt diet, 8% salt+2.5% Ca diet or 2.5% Ca diet for 6–8 weeks has been investigated. The mean arterial pressure of salt loaded rats (148.63±8.54 mmHg) was higher (P<0.05) than those of control (108.36±7.81 mmHg), salt-loaded Ca-fed (101.62±7.38) and Ca fed (98.54±8.72) rats. The maximum KCl-induced relaxation of the aortic rings was least (55.5±3.5%, P<0.05) in salt loaded rats when compared to the maximum KCl-induced relaxation of control (70.76±3.65%), salt+Ca fed (73.12±3.46%) and Ca fed (79.3±3.68%) rats. Salt loading attenuated the maximum relaxation to CaCl₂ (P<0.05) when compared to the maximum relaxation responses of control rats, salt+Ca fed and Ca fed rats. The Mg-induced relaxation was lower (P<0.05) in salt loaded rats than any other group. Increasing the extracellular fluid calcium concentration to 2.61 and 5.1 mmol l⁻¹ significantly (P<0.05) increased the relaxation responses to MgSO₄ in aortic rings from all the groups. The result of this study indicates that salt-loading caused significant increase in the blood pressure of the rats and also reduced the relaxation responses of the aortic rings to KCl, MgSO₄ and CaCl₂ which suggest altered Na⁺,K⁺-ATPase activity and resistance of the vascular smooth muscle membrane to calcium-induced membrane stabilization. These defects were reversed by dietary calcium supplement.     

The impact of hormonal therapy for infertility on the age at menopause

Objectives: To look for possible association between past history of ovulation induction and age at menopause. Design: Women attending our postmenopausal outpatient clinic were asked to fill questionnaires with demographic data, obstetrical history (including treatment for infertility), and medical details related to menopause. Patients: The study group (n=31) consisted of women with a history of ovulation induction, and a control group (n=200) included women who did not experience such intervention. Results: The age at the final menstrual bleeding was 46.4±5 in the study group, and 50±4 for the control group (P<0.001). This difference was most prominent for women who had induction of ovulation prior to age 35 years: they entered menopause at age 43.8±5 years. Smoking had a weak effect on the age at menopause (48.5±4 for current, vs. 49.9±4 for non- or past-smokers; P<0.03). Conclusions: This retrospective and preliminary study raises the question whether hormonal manipulations and ovarian over-stimulation during fertility treatments could be a risk factor for premature menopause.     

Plasma androstenedione and oestrone levels in the climacteric syndrome

Plasma androstenedione (A) and oestrone (E₁) levels were measured by radioimmunoassay in a group of 78 healthy women who had undergone a natural menopause. Of this total, 23 were symptomless (Group 1), 39 presented with a moderate climacteric syndrome (Group 2) and 16 had a severe climacteric syndrome (Group 3). The average body weight was found to be significantly higher in Groups 2 (P < 0.01) and 3 (P < 0.05), than in Group 1, but the age distribution and number of years since the menopause were similar in all three groups. Nevertheless, significantly lower levels of A (0.75± 0.06 ng/ml, P < 0.01, in Group 2; 0.24 ± 0.05 ng/ml, P < 0.001, in Group 3) and E₁ (20.80 ± 2.18 pg/ml, P < 0.05, in Group 2; 12.22 ± 1.65 pg/ml, P < 0.001, in Group 3) were observed in the women with climacteric symptoms than in those with no symptoms (A = 1.08 ± 0.08 ng/ml, E₁ = 27.73 ± 2.22 pg/ml in Group 1).

Since, after the menopause, the concentrations of A and E₁ in the plasma represent the most important source of oestrogens, these results suggest that climacteric symptoms are related to oestrogen deficiency which is secondary to low A production.