Continuous combined hormone replacement therapy with oral 17beta-estradiol and norethisterone acetate improves homocysteine metabolism in postmenopausal women

The effect of 17beta-estradiol plus norethisterone acetate on anthropometric indices: A systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

Little evidence exists on the effect of 17beta-estradiol plus norethisterone acetate on all the anthropometric indices. Hence, this systematic review and meta-analysis of Randomized Controlled Trials was conducted to give an evidence-based report on the effect of 17beta-estradiol plus norethisterone acetate on anthropometric indices.

METHODS

The literature search was executed in databases including PubMed/Medline, Web of Science, Scopus, Embase, and Google Scholar to recognize clinical trials that examined the influence of 17beta-estradiol plus norethisterone acetate on obesity indices from database inception to Jan 2023.

RESULTS

Combined findings were generated from 20 eligible articles. The meta-analysis showed that body weight (Weighted Mean Difference (WMD): -0.47 kg, 95% CI: -1.32, 0.37, p = 0.274), body fat (WMD: 0.16 kg, 95% CI: -1.26, 1.59, p = 0.821), WHR (WMD: 0.001 kg, 95% CI: -0.006, 1.15, p = 0.872), and LBM (WMD: -0.02 kg, 95% CI: -1.19, 1.15, p = 0.970) were not modified in DHEA group compared to the control, but BMI levels were significantly reduced in 17beta-estradiol plus norethisterone acetate group (WMD: -0.15 kg/m2, 95% CI: -0.30, -0.008, p = 0.039). Moreover, based on intervention duration (months), a more significant reduction in BMI was found in trials that were performed on studies with ˃3 months duration (WMD: -0.176 kg/m2) than studies with ≤ 3 months (WMD: 0.05 kg/m2).

CONCLUSION

Administration of 17beta-estradiol plus norethisterone acetate for more than 3 months results in a decrease in BMI, which helps to reduce cardiovascular disease risk.

The influence of 17β-estradiol plus norethisterone acetate treatment on markers of glucose and insulin metabolism in women: a systematic review and meta-analysis of randomized controlled trials

Objective

Despite the fact that some evidence suggests that the administration of 17β-estradiol plus norethisterone acetate influences glucose and insulin metabolism in women, these findings are still contradictory. Thus, we aimed to examine the impact of the co-administration of 17β-estradiol and norethisterone acetate on glycated haemoglobin (HbA1c), fasting glucose, insulin and C-peptide concentrations in females by means of a systematic review and meta-analysis of randomized controlled trials (RCTs).

Methods

We searched four databases (PubMed/MEDLINE, Scopus, Embase, and Web of Science) using specific keywords and word combinations. The random-effects model (DerSimonian and Laird model) was employed to compute the weighted mean difference (WMD) and 95% confidence intervals (CIs) for the variations from baseline of HbA1c, fasting glucose, insulin, and C-peptide concentrations.

Results

In total, 14 RCTs were entered into the quantitative synthesis. The combined administration of 17β-estradiol and norethisterone acetate decreased HbA1c (WMD: -0.65%, 95% CI: -1.15 to -0.15; P=0.011), fasting glucose (WMD: -11.05 mg/dL, 95% CI: -16.6 to -5.5; P<0.001) and insulin (WMD: -1.35 mIU/L, 95% CI: -2.20 to -0.50; P=0.001) levels. C-peptide concentrations' declined only in females diagnosed with overweight/obesity or diabetes.

Conclusion

Evidence to date points out that the administration of 17β-estradiol and norethisterone acetate has a positive impact on glucose metabolism in women by reducing fasting glucose, HbA1c, and insulin values. Future studies need to confirm the potential benefits of this drug combination in the prevention and/or management of cardiometabolic disorders.

Protecting the aging eye with hydrogen sulfide

Research demonstrates that senescence is associated with tissue and organ dysfunction, and the eye is no exception. Sequelae arising from aging have been well defined as distinct clinical entities and vision impairment has significant psychosocial consequences. Retina and adjacent tissues like retinal pigmented epithelium and choroid are the key structures that are required for visual perception. Any structural and functional changes in retinal layers and blood retinal barrier could lead to age-related macular degeneration, diabetic retinopathy, and glaucoma. Further, there are significant oxygen gradients in the eye that can lead to excessive reactive oxygen species, resulting in endoplasmic reticulum and mitochondrial stress response. These radicals are source of functional and morphological impairment in retinal pigmented epithelium and retinal ganglion cells. Therefore, ocular diseases could be summarized as disturbance in the redox homeostasis. Hyperhomocysteinemia is a risk factor and causes vascular occlusive disease of the retina. Interestingly, hydrogen sulfide (H₂S) has been proven to be an effective antioxidant agent, and it can help treat diseases by alleviating stress and inflammation. Concurrent glutamate excitotoxicity, endoplasmic reticulum stress, and microglia activation are also linked to stress; thus, H₂S may offer additional interventional strategy. A refined understanding of the aging eye along with H₂S biology and pharmacology may help guide newer therapies for the eye.

Homocysteine, estrogen and cognitive decline

BACKGROUND

Factors that contribute to cognitive decline in women from midlife remain poorly understood. There are circumstantial data indicating a positive association between homocysteine and cognitive decline and that endogenous and exogenous estrogen may influence homocysteine levels. The aim of this review was to establish what is known of the relationships between cognitive change and homocysteine levels, and the impact of the menopause transition and exogenous estrogen on homocysteine levels.

METHODS

We reviewed the recent published literature from 1993 to 2005 pertaining to the current understanding of the relationship(s) between plasma homocysteine levels and cognitive functioning and endogenous hormone levels and exogenous estrogen use in women.

RESULTS

Hyperhomocysteinemia is consistently associated with cognitive decline. Dietary supplementation with vitamins may assist in normalizing homocysteine levels; however, there is no evidence that this results in favorable effects on cognition. Changes in endogenous estrogen levels are inversely associated with changes in serum homocysteine. Consistent with this, estrogen therapy is associated with reductions in plasma homocysteine, with the greatest effects reported in women with higher levels of homocysteine at baseline. Limited data indicate that tibolone is associated with little change in homocysteine. The use of raloxifene, the most studied selective estrogen receptor modulator, is associated with a modest reduction in homocysteine.

CONCLUSIONS

There are data to suggest an underlying link between homocysteine levels and cognitive decline. There is also evidence for a link between both the menopause transition and use of exogenous estrogen therapy and homocysteine levels. Clinical data do not support a role for exogenous estrogen in the prevention of dementia in older women; however, the 'window of opportunity' theory suggests that there is a need for randomized controlled trials to evaluate the role of estrogen in the early postmenopausal years to protect against cognitive decline in later life.

Effects of low- or high-dose hormone therapy on fasting and post-methionine homocysteine levels in postmenopausal women

OBJECTIVE

To evaluate the effect of two different hormone therapy (HT) doses on fasting and post-methionine homocysteine levels, an independent risk factor for cardiovascular and thromboembolic diseases.

METHODS

Forty-eight women in natural postmenopause randomly received calcium 1 mg/day (control group; n = 12) or calcium plus low dose (1 mg estradiol plus 0.5 mg norethisterone; n = 18) or high dose (2 mg estradiol plus 1 mg norethisterone; n = 18) HT in a 6-month randomized, controlled, prospective study.

RESULTS

Folate levels did not vary in any group, while levels of vitamin B12 significantly decreased after low- (-12.2 +/- 6.6%; p < 0.04) or high-dose HT (-13.9 +/- 6.1%; p < 0.01). Fasting homocysteine was reduced by either HT dose in a way that was inversely related to pretreatment homocysteine levels (-0.675x; r = 0.644; p < 0.0001). Modification of post-load homocysteine increase was influenced by the HT dose and inversely related to the homocysteine response to methionine observed at baseline. The regression slope observed with the low-dose HT (-1.637x; r = 0.57; p < 0.02) was significantly steeper (p < 0.001) than that observed with the high-dose HT (-0.304x; r = 0.554; p < 0.03) dose.

CONCLUSIONS

Low- or high-dose HT similarly influences fasting homocysteine levels. Low-dose HT seems to be more effective than high-dose HT in reducing the post-methionine homocysteine increase.

The effect of postmenopausal hormone therapy with or without folic acid supplementation on serum homocysteine level

OBJECTIVE

To evaluate the effects of postmenopausal hormone therapy (HT) with or without the addition of folic acid (FA) on serum homocysteine levels in a randomized, placebo-controlled design. Additionally, a non-randomized control group with no treatment was included.

METHODS

Forty non-hysterectomized healthy postmenopausal women were randomly allocated to receive either oral continuous combined HT (0.625 mg conjugated equine estrogen with 2.5 mg medroxyprogesterone acetate daily) and oral folic acid (5 mg/day, n = 20) or HT and placebo (n = 20) for 3 months. A control group (n = 15) did not receive any study medication and was followed in the same manner. The fasting total serum homocysteine level was measured by fluorescence polarization immunoassay with a sensitivity of < 0.5 micromol/l. Serum levels of folate, estrogen and lipid profile were also followed.

RESULTS

The mean age of the postmenopausal women was 52 +/- 6 years. Baseline homocysteine level was the highest in the HT + FA group (9.96 +/- 2.82 micromol/l), compared to HT + placebo (9.64 +/- 1.89 micromol/l) and control groups (9.01 +/- 1.83 micromol/l) (ANCOVA, p = 0.022). Low baseline folate and vitamin B12 levels contributed significantly to the high level of baseline homocysteine in the HT + FA group. The addition of FA to HT led to a significant decrease in the serum homocysteine level from the baseline level of 9.96 +/- 2.82 micromol/l to the final level of 8.92 +/- 2.53 micromol/l (p = 0.023). On the other hand, HT alone (HT + placebo group) significantly increased the serum homocysteine level from 9.64 +/- 1.89 micromol/l to 10.22 +/- 1.77 micromol/l without a decline in serum folate level (p = 0.045). The serum homocysteine level in the control group did not change significantly (from 9.01 +/- 1.83 micromol/l to 9.58 +/- 2.05 micromol/l, p = 0.29).

CONCLUSIONS

Three months of oral continuous combined HT increased the fasting total serum homocysteine level without affecting the serum folate level. Lowering the homocysteine level in postmenopausal woman on HT is achievable by folic acid supplementation.

A comparison of the effects of sequential transdermal versus continuous orally administered hormone replacement therapies on plasma total homocysteine levels in postmenopausal women: A randomized, placebo-controlled study

OBJECTIVE

The objective was to determine the effects of transdermal and oral hormone replacement therapies on plasma total homocysteine levels in postmenopausal women.

MATERIAL AND METHODS

One hundred and ten postmenopausal patients were enrolled in the study. Participants were randomized into three groups: in Group A (n = 31) oral continuous combined therapy and in Group B (n = 30) transdermal sequential hormone replacement therapy were given for 6 months. A placebo was administered orally to the control group (Group C, n = 30). Serum homocysteine levels were studied prior to and after 6 months of treatment in all groups.

RESULTS

There were no statistical significant differences in mean serum homocysteine levels among the groups prior to the study. The mean homocysteine levels after 6 months in Groups A-C were also similar.

CONCLUSIONS

Serum homocysteine levels alter with neither oral continuous nor sequential transdermal hormone replacement therapy.

Hyperhomocysteinemia and cardiovascular risk in postmenopausal women: the role of folate supplementation

In the postmenopausal period, cardiovascular diseases are a frequent chronic condition leading to high risk of myocardial infarction and death. Recently hyperhomocysteinemia and even mildly elevated plasma concentrations of homocysteine have been recognized as independent risk factors for vascular damage predisposing to arteriosclerosis. Elevated plasma levels of homocysteine induce vascular endothelial damage and are frequently associated with low folate levels.

In this review we evaluate literature data on some aspects related to menopause and homocysteine metabolism. In particular, we show the effect of folic acid supplementation on homocysteine concentrations and on homocysteine-related thiols, such as cysteine and cysteine-glycine, as well as the relationship with glucose, insulin, and lipidic metabolism in postmenopausal women. We also analyze the influence of folate supplementation on endothelial function, by brachial artery flow-mediated dilatation (endothelium-dependent) and nitroglycerine-induced dilatation (endothelium-independent) before and after a methionine load.

Folate administration in postmenopausal women is able to reduce high plasma homocysteine levels and to modify impaired endothelial function induced by hyperhomocysteinemia.

Clin Chem Lab Med 2007;45:130–5.

Meta-analysis: effect of hormone-replacement therapy on components of the metabolic syndrome in postmenopausal women

AIM

To quantify the effects of hormone-replacement therapy (HRT) on components of the metabolic syndrome in postmenopausal women.

METHODS

Comprehensive searches of electronic databases were performed from April 1966 to October 2004. We included randomized controlled trials that were of at least 8 weeks duration and evaluated the effect of HRT on metabolic, inflammatory or thrombotic components. Insulin resistance was calculated by homeostasis model assessment (HOMA-IR). Subgroup analysis evaluated the effects for transdermal and oral treatment and for diabetic and non-diabetic women.

RESULTS

Pooled results of 107 trials showed that HRT reduced abdominal fat [-6.8% (CI, -11.8 to -1.9%)], HOMA-IR [-12.9% (CI, -17.1 to -8.6%)] and new-onset diabetes [relative risk 0.7 (CI, 0.6-0.9)] in women without diabetes. In women with diabetes, HRT reduced fasting glucose [-11.5% (CI, -18.0 to -5.1%)] and HOMA-IR [-35.8% (CI, -51.7 to -19.8%)]. HRT also reduced low-density lipoprotein/high-density lipoprotein cholesterol ratio [-15.7% (CI, -18.0 to -13.5%)], lipoprotein(a) [Lp(a)] [-25.0% [CI, -32.9 to -17.1%)], mean blood pressure [-1.7% (CI, -2.9 to -0.5%)], E-selectin [-17.3% (CI, -22.4 to -12.1%)], fibrinogen [-5.5% (CI, -7.8 to -3.2%)] and plasminogen activator inhibitor-1 [-25.1% (CI, -33.6 to -15.5%)]. Oral agents produced larger beneficial effects than transdermal agents, but increased C-reactive protein (CRP) [37.6% (CI, 17.4-61.3%)] and decreased protein S [-8.6% CI, -13.1 to -4.1%)], while transdermal agents had no effect.

CONCLUSIONS

HRT reduces abdominal obesity, insulin resistance, new-onset diabetes, lipids, blood pressure, adhesion molecules and procoagulant factors in women without diabetes and reduced insulin resistance and fasting glucose in women with diabetes. Oral agents adversely affected CRP and protein S, while transdermal agents had no effects.

Hormone replacement therapy and cognitive performance in postmenopausal women—a review by cognitive domain

Laboratory, animal and neuroimaging evidences suggest that hormone replacement therapy (HRT) may be beneficial to human cognition. This systematic review includes 26 studies on the association between HRT and cognition and 17 studies on HRT and risk of dementia. It was hypothesised that HRT would have a positive association with cognitive speed and verbal memory and possibly visual memory but not with executive functioning, and would be associated with a decreased risk of dementia. Evidence for HRT's neuroenhancing and neuroprotective properties was also evaluated. There was significant statistical and clinical heterogeneity among studies precluding meta-analysis. Results showed no consistent relationship between HRT and performance in any cognitive domain. Cross-sectional studies tended to report more positive results than longitudinal studies and randomised-controlled trials, particularly in the areas of verbal memory and executive functioning. HRT was associated with decreased risk of dementia in observational studies, but with increased risk in one randomised-controlled trial. Cognitive improvement or maintenance are not secondary benefits of HRT.

Intranasal 17β-estradiol treatment and Vitamin B12, folate and homocysteine in menopause

OBJECTIVE

This study assessed the effect of intranasal administration of 17beta-estradiol (Aerodiol) on plasma levels of homocysteine, Vitamin B12 and folate in postmenopausal women.

METHODS

In all, 26 symptomatic postmenopausal women who had undergone hysterectomy and oophorectomy at least 12 months previously participated in this 6-month randomized prospective clinical study. Menopause was determined by serum FSH level >30 microIU/ml and serum estradiol concentration <30 pg/ml. Intranasal 17beta-estradiol treatment was given once daily at a standard daily dose of 300 microg to 16 women, and 10 did not receive any treatment.

RESULTS

In the group receiving intranasal 17beta-estradiol, mean (+/-S.D.) plasma homocysteine level decreased significantly from pre-treatment values (from 16.68+/-4.33 to 14.15+/-1.18 nmol/ml, p=0.029) and the mean folate level increased (from 4.11+/-0.80 to 5.64+/-1.87 ng/ml, p=0.012). Vitamin B12 levels showed a tendency towards increasing. In the treated group, significant negative correlations were observed between homocysteine and folate values (r=-0.586, p=0.017) and between homocysteine and Vitamin B12 values (r=-0.672, p=0.004). No significant changes were observed in the untreated group.

CONCLUSION

The reduction in plasma homocysteine levels observed after 6 months' treatment with intranasal 17beta-estradiol may reflect an alteration in folate and Vitamin B12 homeostasis.

The effect of hormone therapy on plasma homocysteine levels: a randomized clinical trial*

OBJECTIVE

An elevated plasma homocysteine level is a risk factor for cardiovascular diseases. Hormone therapy (HT) may reduce fasting plasma homocysteine levels. We studied 80 postmenopausal women to determine the effect of medroxyprogesterone acetate (MPA) combined with conjugated equine estrogens (CEE) on fasting plasma homocysteine levels.

DESIGN

In a randomized, double blind, prospective, placebo-controlled study, we randomly assigned 80 healthy postmenopausal women between CEE 0.625 mg/d combined with MPA 2.5 mg/d (n = 20), CEE 0.625 mg/d combined with MPA 5 mg/d (n = 20), unopposed CEE 0.625 mg/d (n = 20), and placebo (n = 20) all given for a duration of 6 months. Fasting plasma homocysteine levels were measured before and at the end of the treatment.

RESULTS

Before treatment, plasma homocysteine concentrations were similar in all groups. After 6 months of unopposed CEE, the mean fasting plasma homocysteine levels decreased by 19.02% when compared with baseline levels (P < 0.05). The mean fasting plasma homocysteine concentrations decreased by 17.63% and 19.56% from baseline in both the CEE plus MPA 2.5 mg/d and CEE plus MPA 5 mg/d groups, respectively (P < 0.05 for each group). In contrast, plasma homocysteine levels increased by 11.66% in the placebo group. The homocysteine lowering effect did not differ significantly among the three groups of women receiving unopposed CEE alone and CEE plus MPA at two different doses.

CONCLUSION

Six months of estrogen therapy (ET) and combined estrogen-progestogen therapy (EPT) significantly lower fasting plasma homocysteine levels in healthy postmenopausal women with equal efficacy.

Hormone replacement influences homocysteine levels in the methionine-loading test: a randomized placebo controlled trial in postmenopausal women

OBJECTIVE

To investigate the mechanism by which exogenous oestrogen influences the homocysteine metabolism in postmenopausal women.

STUDY DESIGN

A randomized placebo controlled trial in which a methionine-loading test was performed, in 25 healthy postmenopausal women, before and after a 12-week oral treatment with placebo or daily 4 mg 17beta-estradiol with (HRT) or without (ERT) 10 mg dydrogesterone. Fasting and post-load homocysteine as well as Vitamins B(6), B(12) and folate were determined.

RESULTS

In both treatment groups a significant 12% decrease in fasting homocysteine was observed. This decrease was accompanied by a post-load homocysteine increase of more than 20%. Vitamin B(6) values were decreased by more than 25%.

CONCLUSION

The hormone therapy induced lowering of fasting homocysteine and Vitamin B(6) levels and an increase in post-load homocysteine, supporting the hypothesis that homocysteine-methionine metabolism is modulated by hormone therapy in postmenopausal women.

Mortality associated with hormone replacement therapy in younger and older women: a meta-analysis

OBJECTIVE

To assess mortality associated with hormone replacement in younger and older postmenopausal women.

DESIGN

A comprehensive search of MEDLINE, CINAHL, and EMBASE databases was performed to identify randomized controlled trials of hormone replacement therapy from 1966 to September 2002. The search was augmented by scanning selected journals through April 2003 and references of identified articles. Randomized trials of greater than 6 months' duration were included if they compared hormone replacement with placebo or no treatment, and reported at least 1 death.

MEASUREMENTS

Outcomes measured were total deaths and deaths due to cardiovascular disease, cancer, or other causes. Odds ratios (OR) for total and cause-specific mortality were reported separately for trials with mean age of participants less than and greater than 60 years at baseline.

MAIN RESULTS

Pooled data from 30 trials with 26,708 participants showed that the OR for total mortality associated with hormone replacement was 0.98 (95% confidence interval [CI], 0.87 to 1.12). Hormone replacement reduced mortality in the younger age group (OR, 0.61; CI, 0.39 to 0.95), but not in the older age group (OR, 1.03; CI, 0.90 to 1.18). For all ages combined, treatment did not significantly affect the risk for cardiovascular or cancer mortality, but reduced mortality from other causes (OR, 0.67; CI, 0.51 to 0.88).

CONCLUSIONS

Hormone replacement therapy reduced total mortality in trials with mean age of participants under 60 years. No change in mortality was seen in trials with mean age over 60 years.

Effects of oral and transdermal 17 beta-estradiol combined with progesterone on homocysteine metabolism in postmenopausal women: a randomised placebo-controlled trial

Mild hyperhomocysteinemia is a risk factor for both ischaemic heart disease and venous thromboembolism. The effects of transdermal estrogen replacement therapy (ERT) on homocysteine metabolism in postmenopausal women have scarcely been investigated. This clinical trial aimed to estimate the effects of combined hormone replacement therapy on the fasting total homocysteine levels according to the estrogen route of administration. We enrolled 196 postmenopausal women, who were randomly allocated to receive on a continuous basis either 1mg of 17 beta-estradiol orally (n = 63) or 50 microg transdermally (n = 68) per day, both combined with a daily intake of 100 mg progesterone, or placebo (n = 65) over a period of 6 months. Neither oral nor transdermal ERT significantly affected total plasma homocysteine levels or red-blood cell folate levels. However, oral ERT significantly decreased plasma vitamin B12 levels compared to placebo (mean relative variation difference over 6 months between oral ERT and placebo: -11.7% (95%CI, -21 to -2%) whereas transdermal ERT did not display any significant effects. Our data show that transdermal ERT as well as low dose of oral ERT does not significantly affect the homocysteine metabolism. This finding does not support a role for transdermal estrogen in the prevention of ischaemic heart disease in postmenopausal women.

Effect of hormone replacement therapy and tibolone on serum total homocysteine levels in postmenopausal women

OBJECTIVE

To assess the effect of continuous combined hormone replacement therapy (HRT) or tibolone on serum total homocysteine (tHcy) levels in postmenopausal women.

STUDY DESIGN

Ninety-five postmenopausal women aged 41-68 years were included in the study. Seventy-three women with climacteric complaints, osteopenia or osteoporosis received either conjugated equine estrogens 0.625 mg combined with medroxyprogesterone acetate 5 mg (CEE/MPA, n=31) or tibolone 2.5 mg (n=42). Twenty-two healthy women, matched for chronological and menopausal age, served as controls. Serum tHcy levels were assessed at baseline, 6, 12 and 18 months.

RESULTS

No difference was recorded between groups regarding demographic characteristics or mean baseline serum tHcy. Serum tHcy levels decreased significantly in the CEE/MPA compared to baseline (change at 18 months: -3.9%, P<0.05). The magnitude of the decrease was higher in the subgroup of women with baseline tHcy levels above the median (change at 18 months: -15.0%, P<0.01). No change in tHcy levels was detected in the tibolone group throughout the study period, either in the whole group (change at 18 months: 1.9%, NS) or in the subgroup with baseline tHcy levels above the median (change at 18 months: -3.23%, NS).

CONCLUSION

Continuous CEE/MPA reduces tHcy especially in women with high pretreatment tHcy levels. Tibolone has no effect on serum tHcy levels at least during the first 18 months of therapy. Larger studies with longer follow-up are required to confirm these results.

Comparison of the effect of oral and transdermal hormone therapy on fasting and postmethionine homocysteine levels

OBJECTIVE

To compare the modifications on basal and post-methionine homocysteine (Hcy) levels induced by transdermal vs. oral continuous combined hormone therapy (HT).

DESIGN

Prospective randomized study.

SETTING

Outpatient service at university hospital.

PATIENT(S)

Twenty-four healthy postmenopausal women.

INTERVENTION(S)

Six-month administration of transdermal (50 microg/d of E(2) and 140-170 microg/d of norethisterone [NET] acetate; n = 12) or oral (2 mg of E(2) and 1 mg of NET acetate; n = 12) HT.

MAIN OUTCOME MEASURE(S)

Fasting levels of Hcy, cysteine (Cys), folate, and vitamin B12. Post-methionine Hcy concentrations.

RESULT(S)

During HT, a slight decrease of fasting Hcy (8.9 [6.7; 15.2] micromol/L vs. 8.3 [4.9; 12.0] micromol/L) and fasting Hcy/Cys, a possible index of Hcy trans-sulfuration (0.061 [0.039; 0.107] micromol/L vs. 0.048 [0.032; 0.093] micromol/L) was observed. Modifications were similar in the transdermal and oral group. Net decreases of Hcy and Hcy/Cys observed during HT were related linearly to pretreatment values (r = 0.821 and r = 0.775, respectively), and were significant for Hcy above, but not below, 9 micromol/L. Transdermal (33.5 [27.5; 75.9] micromol/L vs. 28.4 [17.4; 48.9] micromol/L) or oral HT (36.1 [17.7; 74.8] micromol/L vs. 29.9 [17.5; 50.3] micromol/L), decreased, similarly, post-methionine Hcy levels.

CONCLUSION(S)

Similarly to oral, transdermal HT reduces post-methionine Hcy and fasting Hcy when it is elevated.

Estrogens, homocysteine, vasodilatation and menopause: basic mechanisms, interactions and clinical implications

Estrogens influence the independent cardiovascular risk factor homocysteine as well as vasodilatation. Homocysteine alone also influences vasodilatation, indicating a relational triangle that seems important in interpreting the isolated effects of estrogens on homocysteine metabolism and vasoreactivity. This paper gives an overview of the current understanding regarding vasoreactivity, homocysteine metabolism and the role of estrogens. This is placed against the background of the clinical trials on the effect of postmenopausal hormone replacement therapy on homocysteine levels and addresses the importance of the interaction between homocysteine, estrogens and vasoreactivity.

A randomized placebo-controlled study of the effect of transdermal vs. oral estradiol with or without gestodene on homocysteine levels

OBJECTIVE

To assess the effect of transdermal vs. oral administration of E2 on plasma homocysteine levels and to evaluate the impact of adding a progestogen to these regimens.

DESIGN

Prospective, double-blind, double-dummy, placebo-controlled study.

SETTING

Outpatient clinics in two university hospitals and two teaching hospitals in The Netherlands.

PATIENT(S)

One hundred fifty-two healthy hysterectomized postmenopausal women.

INTERVENTION(S)

Thirteen 28-day treatment cycles with placebo (n = 49); transdermal 17beta-E2, 50 microg (n = 33), oral E2, 1 mg (n = 37), or oral E2, 1 mg, plus gestodene, 25 microg (n = 33), followed by four cycles of placebo in each group.

MAIN OUTCOME MEASURE(S)

Fasting plasma total homocysteine concentrations at baseline and cycle 4, 13, and 17.

RESULT(S)

Mean (+/-SD) homocysteine concentrations in the oral E2 group decreased from baseline to cycle 4 (9.0 +/- 2.5 micromol/L vs. 8.2 +/- 2.0 micromol/L; mean change, -7.6%). Homocystine values in the oral E2 plus gestodene group did not change substantially from baseline to cycle 4 (8.9 +/- 1.6 micromol/L vs. 8.6 +/- 2.0 micromol/L; mean change, -4.4%). No significant changes were observed in the transdermal E2 group. After four washout cycles, the homocysteine concentration had returned to baseline values in all groups.

CONCLUSION(S)

Oral E2 therapy reduced the homocysteine concentration more than did therapy with transdermal E2 or oral E2 plus gestodene. This finding may indicate a role of liver metabolism and suggests that gestodene has a negative effect on these changes.

Effects of low-dose 17-β-estradiol plus norethisterone acetate and tibolone on fasting plasma homocysteine levels in postmenopausal women

BACKGROUND

Many postmenopausal women currently receive hormone replacement therapy. The use of low-dose 17beta-estradiol plus norethisterone acetate and tibolone for hormone replacement therapy is not uncommon in postmenopausal women. Homocysteine, which is known to be an independent risk factor for the development of cardiovascular disease, is found in increased levels postmenopause. This study compared the effects of low-dose 17beta-estradiol plus norethisterone acetate and tibolone on the fasting plasma homocysteine level in healthy postmenopausal women.

METHODS

Healthy postmenopausal women (n = 44) were enrolled in the study. Women randomly assigned received 1 mg of 17beta-estradiol plus 0.5 mg of norethisterone acetate or 2.5 mg tibolone during a period of 12 weeks. Fasting plasma homocysteine levels were measured at baseline, the 4th week, and the 12th week of therapy.

RESULTS

In the 4th week there were no significant changes in plasma homocysteine levels in both groups (p > 0.05). However at the end of the 12th week the plasma homocysteine levels were reduced significantly in both groups (p < 0.05).

CONCLUSION

Low-dose 17beta-estradiol plus norethisterone acetate and tibolone lower the fasting plasma homocysteine levels in healthy postmenopausal women.

Effects of tibolone on plasma homocysteine levels in postmenopausal women

OBJECTIVE

To investigate the effects of tibolone on levels of plasma homocysteine, an independent risk factor for cardiovascular disorders, in postmenopausal women.

DESIGN

Prospective, randomized clinical study.

SETTING

University hospital.

PATIENT(S)

Postmenopausal healthy women.

INTERVENTION(S)

Tibolone (2.5 mg/d) or calcium (1250 mg/d) and conjugated equine estrogens (0.625 mg/d) plus medroxyprogesterone acetate (5 mg/d) were administered orally for 6 months. Blood samples were collected at the start and the end of therapy.

MAIN OUTCOME MEASURE(S)

Plasma homocysteine levels.

RESULT(S)

Administration of tibolone and calcium caused only a 4% decrease in plasma homocysteine levels compared with initial levels. In contrast, conjugated equine estrogens plus medroxyprogesterone acetate caused a 29% decrease in plasma homocysteine levels.

CONCLUSION(S)

Despite the reported beneficial effect of tibolone on the serum lipid profile, tibolone had no statistically significant effect on serum homocysteine levels in postmenopausal women. The possible cardiovascular protective role of tibolone might be unrelated to its effects on homocysteine levels.