The effects of transdermal estradiol alone or with cyclical dydrogesterone on markers of cardiovascular disease risk in postmenopausal women with type 2 diabetes: a pilot study

Reproductive Life Span and Severe Hypoglycemia Risk in Postmenopausal Women with Type 2 Diabetes Mellitus

BACKGROUND

Estrogen promotes glucose homeostasis, enhances insulin sensitivity, and maintains counterregulatory responses in recurrent hypoglycemia in women of reproductive age. Postmenopausal women with type 2 diabetes mellitus (T2DM) might be more vulnerable to severe hypoglycemia (SH) events. However, the relationship between reproductive factors and SH occurrence in T2DM remains unelucidated.

METHODS

This study included data on 181,263 women with postmenopausal T2DM who participated in a national health screening program from January 1 to December 31, 2009, obtained using the Korean National Health Insurance System database. Outcome data were obtained until December 31, 2018. Associations between reproductive factors and SH incidence were assessed using Cox proportional hazards models.

RESULTS

During the mean follow-up of 7.9 years, 11,279 (6.22%) postmenopausal women with T2DM experienced SH episodes. A longer reproductive life span (RLS) (≥40 years) was associated with a lower SH risk compared to a shorter RLS (<30 years) (adjusted hazard ratio [HR], 0.74; 95% confidence interval [CI], 0.69 to 0.80; P for trend <0.001) after multivariable adjustment. SH risk decreased with every 5-year increment of RLS (with <30 years as a reference [adjusted HR, 0.91; 95% CI, 0.86 to 0.95; P=0.0001 for 30-34 years], [adjusted HR, 0.80; 95% CI, 0.76 to 0.84; P<0.001 for 35-39 years], [adjusted HR, 0.74; 95% CI, 0.68 to 0.81; P<0.001 for ≥40 years]). The use of hormone replacement therapy (HRT) was associated with a lower SH risk than HRT nonuse.

CONCLUSION

Extended exposure to endogenous ovarian hormone during lifetime may decrease the number of SH events in women with T2DM after menopause.

Diabetes in Menopause: Risks and Management

The aim of this review is to present, critically appraise and qualitatively synthesize current evidence on the risk of type 2 diabetes mellitus (T2DM) development during menopause, the management of climacteric symptoms in women with T2DM and the management of T2DM in postmenopausal women. Menopause represents the end of reproductive life in women, as a result of ovarian aging. It is characterized by substantial decrease in the endogenous oestrogen concentrations and it is accompanied by alterations in body weight, adipose tissue distribution and energy expenditure, as well as insulin secretion, insulin sensitivity and activity that can predispose to the development of T2DM, independently of, and additively to, aging. Many women in midlife experience climacteric symptoms, including hot flushes and night sweats, resulting in an indication to receive Hormone Replacement Treatment (HRT). HRT has a favourable effect on glucose homeostasis both in women without and with T2DM. The latter was considered in the past as a cardiovascular disease (CVD) equivalent, which would suggest that women with the disease should not receive HRT. However, nowadays evidence exists to support an individualized approach of women based on their CVD risk, as some women with T2DM may be excellent candidates for HRT. Regarding T2DM management for women in menopause, lifestyle intervention, including diet and exercise, constitutes its cornerstone. However, most of these women will eventually require pharmacologic therapy. The most suitable agents should be selected according to their metabolic, cardiovascular and bone effects, taking into consideration the specific characteristics and comorbidities of each postmenopausal woman.

Diabetes: a metabolic and reproductive disorder in women

Reproductive dysfunction is a common but little studied complication of diabetes. The spectrum of reproductive health problems in diabetes is broad, and encompasses delayed puberty and menarche, menstrual cycle abnormalities, subfertility, adverse pregnancy outcomes, and potentially early menopause. Depending on the age at diagnosis of diabetes, reproductive problems can manifest early on in puberty, emerge later when fertility is desired, or occur during the climacteric period. Historically, women with type 1 diabetes have frequently had amenorrhoea and infertility, due to central hypogonadism. With the intensification of insulin therapy and improved metabolic control, these problems have declined, but do persist. Additional reproductive implications of contemporary diabetes management are now emerging, including polycystic ovary syndrome and hyperandrogenism, which are underpinned by insulin action on the ovary. The sharp rise in type 2 diabetes incidence in youth suggests that more women of reproductive age will encounter diabetes-related reproductive problems in their lifetimes. With an ever increasing number of young women living with diabetes, clinicians need to be aware of and equipped for the challenges of navigating reproductive health concerns across the lifespan.

Impact of menopause and diabetes on atherogenic lipid profile: is it worth to analyse lipoprotein subfractions to assess cardiovascular risk in women?

Cardiovascular disease is the leading cause of death in women at advanced age, who are affected a decade later compared to men. Cardiovascular risk factors in women are not properly investigated nor treated and events are frequently lethal. Both menopause and type 2 diabetes substantially increase cardiovascular risk in the female sex, promoting modifications on lipid metabolism and circulating lipoproteins. Lipoprotein subfractions suffer a shift after menopause towards a more atherogenic lipid profile, consisted of hypertriglyceridemia, lower levels of both total high density lipoprotein (HDL) and its subfraction HDL2, but also higher levels of HDL3 and small low-density lipoprotein particles. This review discusses the impact of diabetes and menopause to the lipid profile, challenges in lipoprotein subfractions determination and their potential contribution to the cardiovascular risk assessment in women. It is still unclear whether lipoprotein subfraction changes are a major driver of cardiometabolic risk and which modifications are predominant. Prospective trials with larger samples, methodological standardizations and pharmacological approaches are needed to clarify the role of lipoprotein subfractions determination on cardiovascular risk prediction and intervention planning in postmenopausal women, with or without DM.

Menopause, hormone therapy and diabetes

Over the past three decades, the prevalence of diabetes has increased four-fold. Coupled with the global obesity epidemic and aging of the world's population, a perfect metabolic storm is brewing. The influence of menopause and exogenous estrogen and progestogens must be included in this equation. In this review, criteria for diagnosing diabetes and recommendations for screening are described. The reported effects of menopause on diabetes risk in healthy women are reviewed as well as the relationship between established diabetes and the timing of menopause. The effects of menopausal hormone therapies (MHT) on glucose control in women with diabetes and the effect of MHT on diabetes risk in menopausal women without diabetes are described. Evidence-based strategies to prevent diabetes in midlife women are highlighted. The augmenting effect of diabetes on chronic health concerns of aging women, such as cardiovascular disease, osteoporosis, and cancer, along with current recommendations for screening and prevention are presented. Given the current demographics of today's world, the content of this review may apply to as many as one-third of the average practitioner's postmenopausal patient population.

Soy isoflavone supplementation could reduce body weight and improve glucose metabolism in non-Asian postmenopausal women--a meta-analysis

OBJECTIVE

The objective of this study was to conduct a systematic review and a meta-analysis to confirm the effects of soy isoflavone supplementation on body weight, fasting glucose, and insulin level in non-Asian postmenopausal women.

METHODS

We searched the PubMed, EMBASE, and Cochrane databases up to October 2010 for randomized controlled trials regarding the effects of isoflavone supplementation on body weight, fasting glucose, and insulin level. Pooled estimates and 95% confidence intervals (CIs) were calculated by the fixed-and-random-effects model.

RESULTS

Nine studies with 528 participants for body weight, 11 studies with 1182 participants for fasting glucose, and 11 studies with 1142 participants for fasting insulin were included, respectively. Significant reductions were found in body weight [weighted mean difference (WMD), -0.515; 95%CI: -0.895 to -0.134; P = 0.008), glucose level (WMD, -0.189; 95%CI: -0.344 to -0.033), and fasting insulin level (WMD, -0.940; 95%CI: -1.721 to -0.159) with soy isoflavone supplementation compared with placebo control group in non-Asian postmenopausal women after adjusted by unpublished studies. Furthermore, isoflavone supplementation in shorter duration (<6 mo) could significantly reduce body weight (WMD, -0.506; 95%CI: -0.888 to -0.124; P = 0.009) and longer duration (≥ 6 mo) could significantly reduce blood glucose in postmenopausal women (WMD, -0.270; 95%CI: -0.430 to -0.110; P = 0.001). Meanwhile, more reduction in body weight was observed in the lower dose subgroup (dose < 100 mg). Moreover, it is more effective to reduce body weight and fasting insulin level with soy isoflavone supplementation in normal weight (body mass index < 30) than obese (body mass index ≥ 30) women.

CONCLUSIONS

This meta-analysis showed soy isoflavone supplementation could be beneficial for body weight reduction, glucose, and insulin control in plasma. Large and well-designed studies are recommended to confirm this conclusion.

Metabolic and hormonal parameters in post-menopausal women 10 years after transdermal oestradiol treatment, alone or combined to micronized oral progesterone

BACKGROUND

In the post-Women's Health Initiative Study era few post-menopausal women complete long term hormonal treatment (HT).

OBJECTIVE

To analyse metabolic/hormonal parameters and frequency of the metabolic syndrome (METS) in post-menopausal women after 10 years of HT.

METHODS

Retrospective data from parallel cohorts of post-menopausal women receiving HT for 10 years was analysed. Regimens included: transdermal oestradiol (50 microg) (n=22), sequential cyclic HT with transdermal oestradiol (50 microg) plus 200 mg/day micronized oral progesterone (cycle days 12-25) (n=83), or continuous combined HT with transdermal oestradiol (50 microg) plus 100 mg/day micronized oral progesterone (n=46). A group of women who elected not to use HT served as a control group (n=35).

RESULTS

Frequency of the METS did not significantly increase after 10 years of HT. Oestradiol and sex hormone binding globulin (SHBG) levels displayed a significant increase compared to baseline after 10 years of HT (all regimens). These values were significant higher when compared to the control group. Glucose levels were significantly higher after 10 years in women receiving the sequential cyclic regimen. Although not reaching statistical significance, there was a trend for transdermal oestradiol alone to increase HDL-C and decrease triglyceride levels.

CONCLUSION

Serum oestradiol and SHBG levels were significantly higher after 10 years of transdermal oestradiol, alone or combined with micronized oral progesterone, without differences observed in serum metabolic parameters. More research through randomised clinical trials is required.

Lipoprotein a: where are we now?

PURPOSE OF REVIEW

To provide an update of the literature describing the link between lipoprotein a and vascular disease.

RECENT FINDINGS

There is evidence that elevated plasma lipoprotein a levels are associated with coronary heart disease, stroke and other manifestations of atherosclerosis. Several mechanisms may be implicated, including proinflammatory actions and impaired fibrinolysis.

SUMMARY

Lipoprotein a potentially represents a useful tool for risk stratification in the primary and secondary prevention setting. However, there are still unresolved methodological issues regarding the measurement of lipoprotein a levels. Targeting lipoprotein a in order to reduce vascular risk is hampered by the lack of well tolerated and effective pharmacological interventions. Moreover, it has not yet been established whether such a reduction will result in fewer vascular events. The risk attributed to lipoprotein a may be reduced by aggressively tackling other vascular risk factors, such as low-density lipoprotein cholesterol.

Serum High-Sensitivity C-Reactive Protein and Homocysteine Changes During Hormonal Therapy in Women With Polycystic Ovary Syndrome: A Prospective, Matched Study

The study evaluated the effect of 5 hormonal regimes on serum levels of high-sensitivity C-reactive protein (hsCRP) and homocysteine (Hcy) in women with polycystic ovary syndrome (PCOS). Women with PCOS received (1) conjugated estrogens and cyproterone acetate (n = 22), (2) 17β-estradiol and cyproterone acetate (n = 17), (3) ethinyl-estradiol and cyproterone acetate (high dose; n = 20), (4) ethinyl-estradiol plus cyproterone acetate (low dose; n = 12), or (5) ethinyl-estradiol plus desogetrel (n = 12). Both hsCRP and Hcy levels were measured at baseline and after 4, 7, and 12 months. The 17β-estradiol/cyproterone acetate regime resulted in significant reduction of both hsCRP and Hcy levels (P < .001). The other 4 regimes only resulted in a reduction of Hcy levels (P < .001). In conclusion, the 17β-estradiol/cyproterone acetate regime had the most favorable effects in women with PCOS regarding serum levels of hsCRP and Hcy.

High C‐reactive protein levels are associated with oral hormonal menopausal therapy but not with intrauterine levonorgestrel and transdermal estradiol

OBJECTIVE

Oral hormone replacement therapy (HRT) has been linked to increased cardiovascular (CVD) morbidity. HRT causes a sustained increase in C-reactive protein (CRP), an excellent marker of subclinical inflammation and CVD. The aim of the study was to support our hypothesis that CRP, which is synthesized in the liver, is not increased in association with transdermal/intrauterine HRT.

MATERIAL AND METHODS

A case-control study was performed in which CRP measurements in women receiving levonorgestrel intrauterine system combined with transdermal estradiol (LNG/TDE, n=27) were followed for 9 months or longer. CRP concentrations in these women were compared with those of either oral HRT users (n=20) or controls (n=19).

RESULTS

No significant differences were found in CRP concentrations between the LGN/TDE and control groups (1.8+/-1.2 and 1.8+/-1.8 mg/L, respectively). However, CRP was significantly increased in the oral HRT group (5.5+/-2.9 mg/L, p<0.001).

CONCLUSIONS

CRP is significantly increased by oral HRT but not by the LNG/TDE combination after 9 months of treatment. This trend may explain the preponderance of some menopausal women on HRT being at increased risk for the development of CVD. Therefore, the use of LNG/TDE is acceptable for relief of severe climacteric symptoms possibly not imposing an increased CVD risk documented upon oral HRT.

Effect of 6 months of exercise and isoflavone supplementation on clinical cardiovascular risk factors in obese postmenopausal women: a randomized, double-blind study

OBJECTIVE

To investigate whether 6 months of exercise combined with isoflavone supplementation could improve clinical risk factors that predispose to cardiovascular disease in obese postmenopausal women.

DESIGN

This was a randomized, double-blind, controlled trial in which 50 healthy obese postmenopausal women were divided into two groups and assigned to isoflavone supplementation (n=25) or a placebo (n=25) for 1 year. For the last 6 months, both groups participated in an exercise program (three times per week), at the end of which cardiovascular disease risk factors were compared between groups. Body composition (using dual-energy x-ray absorptiometry), metabolic profile (blood lipids, fasting insulin, fasting glucose, sex hormone-binding globulin, C-reactive protein) were determined at baseline and at 6 and 12 months.

RESULTS

We observed a significant effect of exercise and isoflavone supplementation on body weight, total and abdominal fat mass (kilograms and percentage), body mass index, appendicular fat-free mass, fat-free mass/fat mass ratio, and sex hormone-binding globulin, but not with exercise alone. No difference was observed for other biochemical characteristics, although the quantitative insulin sensitivity check index increased equally in both groups. Conversely, although not significant, we observed a tendency for a treatment effect on body mass index (P=0.07) and on absolute (kilograms) (P=0.07) and percentage of (P=0.053) abdominal fat mass, whereas no effect of treatment was found for other variables using the Mann-Whitney test.

CONCLUSIONS

Compared to an aerobic exercise program alone, 70 mg/day of isoflavones combined with exercise may promote significant improvements in body composition parameters that are known to influence cardiovascular disease risk in postmenopausal women.

Estrogen and hypertension

Menopause is accompanied by a dramatic rise in the prevalence of hypertension in women, suggesting a protective role of endogenous estradiol on blood pressure (BP). Both animal experimental and human clinical investigations suggest that estrogen engages several mechanisms that protect against hypertension, such as activation of the vasodilator pathway mediated by nitric oxide and prostacyclin and inhibition of the vasoconstrictor pathway mediated by the sympathetic nervous system and angiotensin. However, emerging evidence from recent clinical trials indicates a small increase, rather than decrease, in systolic BP with oral estrogen administration in postmenopausal women, without any detectable effect on diastolic BP. Mechanisms underlying this selective rise in systolic BP in postmenopausal women and oral contraceptive-induced hypertension in premenopausal women remain unknown, but the rise may be related to supraphysiologic concentration of estrogen in the liver. To date, transdermal delivery of estrogen, which avoids the first-pass hepatic metabolism of estradiol, appears to have a small BP-lowering effect in postmenopausal women and may be a safer alternative in hypertensive women.

Hormone replacement therapy is associated with increased C-reactive protein in women with Type 2 diabetes in the Diabetes Heart Study

AIMS

Increased levels of inflammatory biomarkers, especially C-reactive protein (CRP), are associated with increased risk for cardiovascular disease (CVD) events, such as myocardial infarction, stroke, peripheral vascular disease, and sudden cardiac death. Medical interventions that increase CRP levels, such as hormone replacement therapy (HRT) in post-menopausal women, are under increasing scrutiny. The effect of HRT on CRP levels in women with Type 2 diabetes (T2DM) is not well documented, and conflicting conclusions have been reported. The aim of this study was to determine the influence of HRT on women with diabetes in a large cross-sectional study.

METHODS

Three hundred and twenty-seven post-menopausal women with T2DM from the Diabetes Heart Study participated. Current use of HRT was determined and serum CRP levels were measured using a high-sensitivity ELISA kit. Generalized estimating equation methods were used to assess the relationship of multiple clinical and lifestyle (e.g. smoking) measures on CRP levels including differences between women taking HRT (HRT+) and not taking HRT (HRT-).

RESULTS

Overall serum CRP levels were strongly associated with body mass index (P < 0.0001) and age (P < 0.0001). Of the women, 243 were not using HRT and 84 were using HRT. HRT+ and HRT- women did not differ significantly in measures of clinical traits, with the exception of higher mean low-density lipoprotein cholesterol in HRT- women (P = 0.004). In all models tested, HRT+ women had significantly higher circulating CRP levels, with P-values ranging from 0.0045 to 0.010.

CONCLUSIONS

In this study of serum CRP concentration as a function of HRT in women with Type 2 diabetes, there was consistent evidence for increased circulating CRP levels in women receiving oestrogen-containing HRT. Whether HRT-induced increases in CRP can account for the adverse cardiovascular effects of HRT remains to be established; however, based on these data, there is little reason to believe that diabetic women would be spared from such an effect.

The effect of continuous combined HRT on glucose homeostasis and plasma lipids

BACKGROUND

Hyperandrogenicity in women is a risk factor for cardiovascular disease and noninsulin-dependent diabetes mellitus (NIDDM). Estradiol alone decreases hyperandrogenicity and have beneficial effects on glucose metabolism and plasma lipids in postmenopausal women with type 2 diabetes.

OBJECTIVES

To analyse effects on glucose homeostasis and plasma lipids by 2 mg estradiol and 1mg norethisterone acetate (NETA) given as a daily tablet during 6 months in postmenopausal women with type 2 diabetes.

DESIGN

Randomised, double-blind, placebo-controlled, cross-over design.

MATERIAL AND METHODS

Thirty-one postmenopausal women with type 2 diabetes, glycosylated haemoglobin (HbA1c) of 6% or more and sex hormone-binding globulin (SHBG) values of 60 nmol/L or less were included. Anthropometric variables, blood pressure, sex steroid hormones, HbA1c, serum and lipoprotein lipids, plasminogen activator inhibitor 1 (PAI-1) and insulin-like growth factor 1 (IGF-1) were measured. An oral glucose tolerance test (OGTT) was performed and blood glucose, insulin and C-peptide were analysed. All measurements were taken at baseline and after each 6-month period.

RESULTS

An increase of SHBG and a decrease in free testosterone and PAI-1 levels was induced by the estradiol/NETA treatment compared with placebo. Lipoprotein(a) decreased but otherwise lipid metabolism was unaffected. No differences were recorded in glucose homeostasis between active treatment and placebo.

CONCLUSION

Estradiol/NETA therapy decreased hyperandrogenicity in postmenopausal women with type 2 diabetes. Lipoprotein(a) and PAI-1 which are independent risk factors for coronary heart disease decreased. No changes in glucose homeostasis were found.

Effects of Transdermal Estrogen Replacement Therapy on Cardiovascular Risk Factors

The prevalence of hypertension and cardiovascular disease increases dramatically after menopause in women, implicating estrogen as having a protective role in the cardiovascular system. However, recent large clinical trials have failed to show cardiovascular benefit, and have even demonstrated possible harmful effects, of opposed and unopposed estrogen in postmenopausal women. While these findings have led to a revision of guidelines such that they discourage the use of estrogen for primary or secondary prevention of heart disease in postmenopausal women, many investigators have attributed the negative results in clinical trials to several flaws in study design, including the older age of study participants and the initiation of estrogen late after menopause.Because almost all clinical trials use oral estrogen as the primary form of hormone supplementation, another question that has arisen is the importance of the route of estrogen administration with regards to the cardiovascular outcomes. During oral estrogen administration, the concentration of estradiol in the liver sinusoids is four to five times higher than that in the systemic circulation. This supraphysiologic concentration of estrogen in the liver can modulate the expression of many hepatic-derived proteins, which are not observed in premenopausal women. In contrast, transdermal estrogen delivers the hormone directly into the systemic circulation and, thus, avoids the first-pass hepatic effect.Although oral estrogen exerts a more favorable influence than transdermal estrogen on traditional cardiovascular risk factors such as high- and low-density lipoprotein-cholesterol levels, recent studies have indicated that oral estrogen adversely influences many emerging risk factors in ways that are not seen with transdermal estrogen. Oral estrogen significantly increases levels of acute-phase proteins such as C-reactive protein and serum amyloid A; procoagulant factors such as prothrombin fragments 1+2; and several key enzymes involved in plaque disruption, while transdermal estrogen does not have these adverse effects.Whether the advantages of transdermal estrogen with regards to these risk factors will translate into improved clinical outcomes remains to be determined. Two ongoing clinical trials, KEEPS (Kronos Early Estrogen Prevention Study) and ELITE (Early versus Late Intervention Trial with Estradiol) are likely to provide invaluable information regarding the role of oral versus transdermal estrogen in younger postmenopausal women.

Prevention and treatment of the metabolic syndrome

The prevalence of the metabolic syndrome is increasing owing to lifestyle changes leading to obesity. This syndrome is a complex association of several interrelated abnormalities that increase the risk for cardiovascular disease and progression to diabetes mellitus (DM). Insulin resistance is the key factor for the clustering of risk factors characterizing the metabolic syndrome. The National Cholesterol Education Program (NCEP) Adult Treatment Panel (ATP) III defined the criteria for the diagnosis of the metabolic syndrome and established the basic principles for its management. According to these guidelines, treatment involves the improvement of the underlying insulin resistance through lifestyle modification (eg, weight reduction and increased physical activity) and possibly by drugs. The coexistent risk factors (mainly dyslipidemia and hypertension) should also be addressed. Since the main goal of lipid-lowering treatment is to achieve the NCEP low-density lipoprotein cholesterol (LDL-C) target, statins are a good option. However, fibrates (as monotherapy or in combination with statins) are useful for the treatment of the metabolic syndrome that is commonly associated with hypertriglyceridemia and decreased high-density lipoprotein cholesterol (HDL-C) levels. The blood pressure target is < 140/90 mm Hg. The effect on carbohydrate homeostasis should possibly be taken into account in selecting an antihypertensive drug. Patients with the metabolic syndrome commonly have other less well-defined metabolic abnormalities (eg, hyperuricemia and raised C-reactive protein levels) that may also be associated with an increased cardiovascular risk. It seems appropriate to manage these abnormalities. Drugs that beneficially affect carbohydrate metabolism and delay or even prevent the onset of DM (eg, thiazolidinediones or acarbose) could be useful in patients with the metabolic syndrome. Furthermore, among the more speculative benefits of treatment are improved liver function in nonalcoholic fatty liver disease and a reduction in the risk of acute gout.

17beta-Estradiol replacement improves renal function and pathology associated with diabetic nephropathy

The protective factor of female gender appears to be lost in diabetes; the incidence of diabetes and its complications, including diabetic nephropathy, are equal in women and men. This study examined the effects of estrogen deficiency by ovariectomy (OVX) and replacement with 17beta-estradiol (OVX+E2) on renal function and pathology in the nondiabetic (ND) and streptozotocin (STZ)-induced diabetic (D) rat kidneys for 12 wk. Diabetes was associated with an increase in urine albumin excretion (UAE; ND, 0.39 +/- 0.03; D, 5.9 +/- 0.8 mg/day; P < 0.001), decrease in creatinine clearance (CrCl; ND, 0.69 +/- 0.03; D, 0.43 +/- 0.09 mg x min(-1) x 100 g body wt(-1); P < 0.05), increase in the index of glomerulosclerosis [GSI; ND, 0.01 +/- 0.01; D, 0.15 +/- 0.04 arbitrary units (AU); P < 0.01], tubulointerstitial fibrosis (TIFI; ND, 0.04 +/- 0.04; D, 0.68 +/- 0.2 AU; P < 0.01), and transforming growth factor-beta (TGF-beta) protein expression (ND, 0.61 +/- 0.02; D, 1.25 +/- 0.07 AU; P < 0.01). In the D group, the severity of these changes was augmented with OVX (UAE, 8.1 +/- 0.6 mg/day; CrCl, 0.40 +/- 0.04 mg x min(-1) x 100 g body wt(-1); GSI, 0.29 +/- 0.04 AU; TIFI, 0.90 +/- 0.06 AU; TGF-beta, 1.26 +/- 0.10 AU), whereas E2 replacement attenuated these changes (UAE, 6.3 +/- 0.8 mg/day; CrCl, 0.66 +/- 0.03 mg x min(-1) x 100 g body wt(-1); GSI, 0.06 +/- 0.02 AU; TIFI, 0.36 +/- 0.08 AU; TGF-beta, 0.57 +/- 0.08 AU). We conclude that E2 deficiency increases the severity of renal disease in a diabetic animal model and that E2 replacement is renoprotective by attenuating the decline in renal function and pathology associated with diabetes.

Estrogens, lipoproteins, and cardiovascular risk factors: an update following the randomized placebo-controlled trials of hormone-replacement therapy

PURPOSE OF REVIEW

The effects of hormone-replacement therapy on cardiovascular risk factors are examined. In an attempt to explain the results of recent randomized controlled trials in which no benefit of hormone-replacement therapy for postmenopausal women has been observed,

RECENT FINDINGS

Changes in lipoproteins in response to hormone-replacement therapy have now been analysed for both primary and secondary prevention studies. In none of the large randomized controlled trials was there any effect of hormone-induced changes in low-density lipoprotein, high-density lipoprotein, or triglyceride on clinical outcome. Further detailed studies of lipoprotein metabolism have not revealed any adverse effect of hormone-replacement therapy. Recent analysis of the Heart Estrogen/Progestin-Replacement Study data suggests hormone-replacement therapy reduces the risk of developing diabetes. The effect of hormone-replacement therapy on inflammatory markers and on flow-mediated dilatation is largely beneficial, although the effect on flow-mediated dilatation is modulated according to endothelial function, which is adversely affected by known risk factors, including age and presence of atherosclerosis. In this respect the work on polymorphisms of estrogen receptor-alpha may in due course help to define those women who would benefit most from use of estrogen. Crucially, oral but not transdermal hormone-replacement therapy increases activated protein C resistance independently of the presence of factor V Leiden. This effect increases the risk of venous thromboembolic events, which is reflected in the results of a hospital case control study of thromboembolism.

SUMMARY

Despite the outcome of the hormone-replacement therapy trials, recent work has confirmed the putative antiatherogenic effects of hormone-replacement therapy on lipoprotein metabolism. Metabolic differences of route of administration of estrogen, particularly on haemostatic variables, may explain this clinical paradox, which continues to be an important research area.