Effect of raloxifene -- a selective oestrogen receptor modulator -- on kidney function in post-menopausal women with Type 2 diabetes: results from a randomized, placebo-controlled pilot trial

Greb1 Transiently Accelerates Pancreatic β-Cell Proliferation in Diabetic Mice Exposed to Estradiol

Decrease of pancreatic β cells leads to diabetes. In an inducible cAMP early suppressor (ICER-Iγ) transgenic mouse model of severe type 2 diabetes with reduced insulin production and depleted β cells, supplementation with high concentrations of 17β-estradiol (E2) markedly enhances β-cell proliferation and normalizes glucose levels. The current study explored the underlying mechanisms leading to a dynamic increase of β cells and pathologic changes in diabetic mice exposed to E2. Gene expression profiling of pancreatic islets of 6-month-old ICER-transgenic mice recovering from diabetes due to elevated E2 levels identified growth regulation by estrogen in breast cancer 1 (Greb1) as a gene significantly up-regulated during the recovery phase. To substantiate this, β-cell-specific Greb1-deficient mice were generated, and Greb1 was shown to be essential for recovery of depleted β cells in diabetic mice. Graft growth and glucose lowering were observed in 50 islets with increased Greb1 expression transplanted adjacent to E2 pellets beneath the kidney capsule of streptozotocin-induced diabetic mice. Greb1 expression due to a drastic increase in exogenous or endogenous E2 was transient and closely correlated with changes in E2-related and some cell cycle-related genes. These findings provide new insights into in vivo proliferation of deficient β cells and suggest the possibility of new therapeutic approaches targeting pancreatic β cells that could revolutionize the concept of diabetes treatment, which has been considered difficult to cure completely.

Role of Sex Hormones in Prevalent Kidney Diseases

Chronic kidney disease (CKD) is a constantly growing global health burden, with more than 840 million people affected worldwide. CKD presents sex disparities in the pathophysiology of the disease, as well as in the epidemiology, clinical manifestations, and disease progression. Overall, while CKD is more frequent in females, males have a higher risk to progress to end-stage kidney disease. In recent years, numerous studies have highlighted the role of sex hormones in the health and diseases of several organs, including the kidney. In this review, we present a clinical overview of the sex-differences in CKD and a selection of prominent kidney diseases causing CKD: lupus nephritis, diabetic kidney disease, IgA nephropathy, and autosomal dominant polycystic kidney disease. We report clinical and experimental findings on the role of sex hormones in the development of the disease and its progression to end-stage kidney disease.

Role of sex hormones in diabetic nephropathy

Diabetic nephropathy (DN) is the most common microvascular complication in diabetes and one of the leading causes of end-stage renal disease. The standard treatments for patients with classic DN focus on blood glucose and blood pressure control, but these treatments can only slow the progression of DN instead of stopping or reversing the disease. In recent years, new drugs targeting the pathological mechanisms of DN (e.g., blocking oxidative stress or inflammation) have emerged, and new therapeutic strategies targeting pathological mechanisms are gaining increasing attention. A growing number of epidemiological and clinical studies suggest that sex hormones play an important role in the onset and progression of DN. Testosterone is the main sex hormone in males and is thought to accelerate the occurrence and progression of DN. Estrogen is the main sex hormone in females and is thought to have renoprotective effects. However, the underlying molecular mechanism by which sex hormones regulate DN has not been fully elucidated and summarized. This review aims to summarize the correlation between sex hormones and DN and evaluate the value of hormonotherapy in DN.

Sex and Gender Related Differences in Diabetic Kidney Disease

Diversity in sex and gender are important considerations in the pathogenesis, prognostication, research, and management of diabetic kidney disease (DKD). Sex and gender differences in the disease risk, disease-specific mechanisms, and outcomes in DKD may be attributed to biological differences between males and females at the cellular and tissue level, inconsistencies in the diagnostic and assessment tools used in chronic kidney disease and DKD, as well societal differences in the way men, women, and gender-diverse individuals self-manage and interact with health care systems. This review outlines key considerations related to the impact of sex on DKD, specifically elaborating on how they contribute to observed differences in disease epidemiology, pathogenesis, and treatment strategies. We also highlight the effect of gender on DKD progression and care.

Raloxifene in the Treatment of Osteoporosis in Postmenopausal Women with End-Stage Renal Disease: A Systematic Review and Meta-Analysis

As a selective estrogen receptor modulator (SERM), raloxifene is used in healthy postmenopausal women to prevent bone loss and reduce fractures. However, the benefit of raloxifene is uncertain in the treatment of osteoporosis among patients with end-stage renal disease (ESRD) or those who require maintenance dialysis. We assessed the safety and efficacy of raloxifene in this particular population. Studies were selected from PubMed, Springer, CNKI (Chinese National Knowledge Infrastructure) and Wanfang Database. Randomized controlled trials (RCTs) and prospective studies with control/placebo groups were included. Five studies were included with a total of 244 participants (121 patients in the raloxifene group and 123 patients in the placebo/control group). The median duration of treatment was 12 months. The incidence rate of side effects of raloxifene was 0/121 (0%). There was a significant improvement of lumbar spine bone mineral density (BMD) levels in the raloxifene group compared with the placebo group (MD: 33.88, 95% CI: 10.93, 56.84, p=0.004). There was no significant difference concerning the improvement of femoral neck BMD (MD: 8.42, 95% CI: -10.21, 27.04, p=0.38), intact parathyroid hormone (iPTH) (MD: -12.62, 95% CI: -35.36, 10.13, p=0.28), calcium (MD: -0.08, 95% CI: -0.61, 0.44, p=0.76), phosphorus (MD: 0.18, 95% CI: -0.12, 0.48, p=0.23) or bone alkaline phosphatase (BAP) (MD: -4.33, 95% CI: -14.44, 5.79, p=0.40). Raloxifene seems to be effective in improving the lumbar spine BMD in postmenopausal women with ESRD. More large RCTs are necessary to evaluate the long-term safety of raloxifene in uremic patients.

The Effect of Raloxifene Treatment on Lipid Profile in Elderly Individuals: A Systematic Review and Meta-analysis of Randomized Clinical Trials

PURPOSE

To perform a systematic review and meta-analysis of randomized clinical trials (RCTs) to elucidate the effects of raloxifene on the lipid profile in elderly individuals.

METHODS

A systematic review and meta-analysis of RCTs was performed following the PRISMA statement. Data on triglycerides (TGs), total cholesterol (TC), HDL-C, and LDL-C were extracted. Relevant publications up to October 2020 were detected through searches in the PubMed/MEDLINE, Web of Science, Scopus, and Embase databases. Changes were reported as weighted mean differences (WMDs) and 95% CIs using random-effects models.

FINDINGS

Nine studies were selected, with a duration of intervention ranging from 2 and 12 months and a raloxifene dose of 60 to 120 mg/d. Studies were performed in healthy individuals and in those with disorders, such as osteoporosis, type 2 diabetes, and kidney disease required long-term hemodialysis. Overall, TG (WMD, -6.50 mg/dL; 95% CI, -34.18 to 21.20 mg/eL; P = 0.646), LDL-C (WMD, -17.86 mg/dL; 95% CI, -42.44 to 6.72 mg/dL; P = 0.154), and HDL-C (WMD, 2.35 mg/dL; 95% CI, -1.14 to 5.84 mg/dL; P = 0.187) levels did not change significantly after the administration of raloxifene. In contrast, TC levels decreased after raloxifene therapy (WMD, -6.59 mg/dL; 95% CI, -13.13 to -0.05 mg/dL; P = 0.048).

IMPLICATIONS

Raloxifene therapy decreased TC levels but did not alter TG, HDL-C, and LDL-C concentrations in elderly individuals. Regarding the LDL-C levels, although the finding lacked statistical significance, we believe that there was a mean reduction that deserves further clinical attention as much as TC.

Gender Differences in Diabetic Kidney Disease: Focus on Hormonal, Genetic and Clinical Factors

Diabetic kidney disease (DKD) is one of the most serious complications of both type 1 (T1DM) and type 2 diabetes mellitus (T2DM). Current guidelines recommend a personalized approach in order to reduce the burden of DM and its complications. Recognizing sex and gender- differences in medicine is considered one of the first steps toward personalized medicine, but the gender issue in DM has been scarcely explored so far. Gender differences have been reported in the incidence and the prevalence of DKD, in its phenotypes and clinical manifestations, as well as in several risk factors, with a different impact in the two genders. Hormonal factors, especially estrogen loss, play a significant role in explaining these differences. Additionally, the impact of sex chromosomes as well as the influence of gene-sex interactions with several susceptibility genes for DKD have been investigated. In spite of the increasing evidence that sex and gender should be included in the evaluation of DKD, several open issues remain uncovered, including the potentially different effects of newly recommended drugs, such as SGLT2i and GLP1Ras. This narrative review explored current evidence on sex/gender differences in DKD, taking into account hormonal, genetic and clinical factors.

Sex-related differences in diabetic kidney disease: A review on the mechanisms and potential therapeutic implications

Sexual dimorphism may play a key role in the pathogenesis of diabetic kidney disease (DKD) and explain differences observed in disease phenotypes, responses to interventions, and disease progression between men and women with diabetes. Therefore, omitting the consideration of sex as a biological factor may result in delayed diagnoses and suboptimal therapies. This review will summarize the effects of sexual dimorphism on putative metabolic and molecular mechanisms underlying DKD, and the potential implications of these differences on therapeutic interventions. To successfully implement precision medicine, we require a better understanding of sexual dimorphism in the pathophysiologic progression of DKD. Such insights can unveil sex-specific therapeutic targets that have the potential to maximize efficacy while minimizing adverse events.

Raloxifene has favorable effects on the lipid profile in women explaining its beneficial effect on cardiovascular risk: A meta-analysis of randomized controlled trials

There is robust evidence that the appropriate treatment of dyslipidaemia substantially reduces cardiovascular disease-related morbidity and mortality. Raloxifene is a selective oestrogen receptor modulator that also interferes with the lipid metabolism and may be of aid in the management of lipid abnormalities in females. Therefore, we conducted a systematic review and meta-analysis of the available randomized clinical trials (RCTs) exploring the effect of raloxifene on the lipid profile in women. The Scopus, Web of Science, PubMed/Medline and EMBASE databases were systematically and independently searched by two assessors from inception until 20 November 2020 without time and language restrictions. The overall findings were generated from 30 eligible RCTs. As compared to controls, raloxifene resulted in a significant elevation of the high-density lipoprotein-cholesterol (HDL-C) (WMD: 2.41 mg/dL, 95% CI: 0.84-3.97, P = 0.003) and a significant reduction of the total cholesterol (TC) (WMD:-14.84 mg/dL, 95% CI: -20.37 to -9.317, P = 0.000) and of the low-density lipoprotein-cholesterol (LDL-C) (WMD: -17 mg/dL, 95% CI: -25.77, -8.22, P = 0.000). In the stratified analysis, a significant decrease of serum triglycerides (TG) (WMD: -22.06 mg/dL) was achieved in the RCTs with a duration of ≤ 26 weeks (WMD -8.70 mg/dL) and with baseline TG concentrations of ≥ 130 mg/dL (WMD: -23.02 mg/dL). In conclusion, raloxifene treatment can increase HDL-C and lower LDL-C and TC. In terms of TG, a significant decrease can be observed if the administration of raloxifene lasts ≤ 26 weeks and if the baseline TG concentrations are ≥ 130 mg/dL.

Sex-specific associations of insulin resistance with chronic kidney disease and kidney function: a bi-directional Mendelian randomisation study

AIMS/HYPOTHESIS

Reasons for the sexual disparity in chronic kidney disease (CKD) are unclear. To provide insight we contextualised these differences within evolutionary biology, and explored sex-specific effects of insulin resistance because it may have sex-specific effects on the reproductive axis. Impaired kidney function may also cause insulin resistance. We assessed these possibilities using bi-directional, sex-specific, two-sample Mendelian randomisation (MR).

METHODS

Given that fasting insulin, fasting glucose and HbA_1c are related, we used MR-Bayesian model averaging (MR-BMA) to identify the best-fitting model and most influential exposure. Genetic associations with glycaemic traits were obtained from genome-wide association studies (GWAS) in Europeans without diabetes (n = 108,557 for fasting insulin, as a proxy for insulin resistance, and for fasting glucose, n = 123,665 for HbA_1c in the Meta-Analyses of Glucose and Insulin-related traits Consortium [MAGIC]), and applied to GWAS of 480,698 Europeans for overall associations with CKD (cases n = 41,395) and eGFR. We also used sex-specific individual information in white British (179,917 men, 6016 CKD cases; 212,079 women, 5958 CKD cases) from the UK Biobank. Univariable or multivariable MR was used to assess the role of glycaemic trait(s) selected by MR-BMA in CKD and kidney function. Genetic variants predicting eGFR were used to assess the role of kidney function in the most influential exposure(s).

RESULTS

Fasting insulin was selected as the most likely exposure by both overall and sex-specific MR-BMA. It increased CKD in men (OR 7.23 per pmol/l higher fasting insulin [95% CI 2.46, 21.2]) but not in women (OR 1.05 [95% CI 0.21, 5.21]), and reduced eGFR in men (-0.04 [95% CI -0.07, -0.01]) but not in women (0.01 [95% CI -0.02, 0.03]). Genetically predicted eGFR was unrelated to fasting insulin.

CONCLUSIONS/INTERPRETATION

Genetically predicted fasting insulin was sex-specifically associated with CKD and unhealthier kidney function but was not affected by kidney function. Graphical abstract.

Bazedoxifene improves renal function and increases renal phosphate excretion in patients with postmenopausal osteoporosis

INTRODUCTION

Because aging is a predictor of renal insufficiency in the general population, renal function is a concern in postmenopausal patients undergoing treatment for osteoporosis. Although high serum phosphate concentration is a predictor of renal insufficiency, the effect of selective estrogen receptor modulator (SERM) on renal function and phosphate homeostasis remains to be established.

MATERIALS AND METHODS

We administered 20 mg/day bazedoxifene to 48 postmenopausal osteoporotic women who had been taking alfacalcidol for ≥ 6 months, and assessed lumbar spine bone mineral density (LS-BMD), renal function (by calculating estimated glomerular filtration rate using serum cystatin-C levels [eGFRcys] [range 38.0-98.2 mL/min/1.73 m²]), and phosphate homeostasis.

RESULTS

LS-BMD was significantly higher 6 months after the initiation of bazedoxifene administration. eGFRcys had increased by 3 months after initiation and was stable until 12 months. Serum phosphate gradually decreased after initiation, reaching statistical significance at 6 months. The changes in serum phosphate were also significant when the maximum tubular reabsorption rate of phosphate was normalized to glomerular filtration rate (TmP/GFR), indicating that bazedoxifene treatment reduces serum phosphate by increasing the urinary excretion of phosphate. The change in eGFRcys after the initiation of bazedoxifene was significantly negatively correlated with the change in serum phosphate, suggesting that a reduction in serum phosphate improves renal function.

CONCLUSION

Bazedoxifene improves renal function, possibly by increasing renal phosphate excretion, in postmenopausal osteoporotic women without severe renal insufficiency.

Sex Differences in Diabetic Kidney Disease

While the global prevalence of both type 1 and type 2 diabetes mellitus is similar in men and women, the consequences of diabetes on associated end-organ complications, including diabetic kidney disease appear to be more sex-specific. Particularly, women with diabetes have higher mortality rates for diabetes-related deaths, and higher prevalence of diabetic kidney disease risk factors such as hypertension, hyperglycemia, obesity, and dyslipidemia. However, the evidence for the impact of sex on diabetic kidney disease prevalence and disease progression is limited and inconsistent. Although most studies agree that the protective effect of the female sex against the development of kidney disease is diminished in the setting of diabetes, the reasons for this observation are unclear. Whether or not sex differences exist in the risk of diabetic kidney disease is also unclear, with studies reporting either higher risk in men, women, or no sex differences. Despite the remaining controversies, some of the factors that associate with sex differences in the risk of diabetic kidney disease are age at onset, and type and duration of diabetes. There is growing appreciation of the importance of sex hormones in the regulation of renal function, with estrogens generally considered to be renoprotective. Although some progress has been made towards better understanding of the mechanisms by which sex hormones play a role in the pathophysiology of diabetic kidney disease, the translational potential of this knowledge is still underappreciated. A better understanding of sex differences in diabetic kidney disease may provide basis for personalized and sex-specific treatment of diabetic kidney disease.

Effect of age at menarche on microvascular complications among women with Type 1 diabetes

AIM

To test the hypothesis that delayed menarche is associated with an increased microvascular complication risk among women with Type 1 diabetes.

METHODS

We studied the female participants of an ongoing prospective study of childhood-onset Type 1 diabetes diagnosed during the period 1950-1980. Of 325 women, we included data from 315 who had reached menarche by the study baseline (1986-1988) and who self-reported their age at menarche. Both cross-sectional and prospective analyses over the 25-year follow-up were used to assess the relationship of age at menarche with the prevalence, incidence and cumulative incidence of microvascular complications, comprising overt nephropathy, proliferative retinopathy and confirmed distal symmetric polyneuropathy.

RESULTS

In cross-sectional analyses at baseline, the odds of overt nephropathy increased 1.24 times (P=0.02) with each annual increase in age at menarche, and 3.2 times (P=0.009) in those with delayed menarche compared with women with normal menarche onset, after adjustment. Similarly, the cumulative incidence of overt nephropathy increased 1.16 times (P=0.01) with each older year of menarche and women with delayed menarche were at twofold increased risk of overt nephropathy (hazard ratio 2.30, P=0.001) compared with women with normal menarche onset. However, age at menarche was not significantly associated with either proliferative retinopathy or confirmed distal symmetric polyneuropathy after adjusting for covariates.

CONCLUSIONS

Age at menarche was significantly associated with the prevalence and cumulative incidence of overt nephropathy, but not with proliferative retinopathy or confirmed distal symmetric polyneuropathy in Type 1 diabetes. Women with delayed menarche may therefore be targeted for early screening and timely interventions to prevent the development of nephropathy.

Type 2 Diabetes and Osteoporosis: A Guide to Optimal Management

CONTEXT

Both type 2 diabetes (T2D) and osteoporosis are affected by aging and quite often coexist. Furthermore, the fracture risk in patients with T2D is increased. The aim of this article is to review updated information on osteoporosis and fracture risk in patients with T2D, to discuss the effects of diabetes treatment on bone metabolism, as well as the effect of antiosteoporotic medications on the incidence and control of T2D, and to provide a personalized guide to the optimal management.

EVIDENCE ACQUISITION

A systematic literature search for human studies was conducted in three electronic databases (PubMed, Cochrane, and EMBASE) until March 2017. Regarding recommendations, we adopted the grading system introduced by the American College of Physicians.

EVIDENCE SYNTHESIS

The results are presented in systematic tables. Healthy diet and physical exercise are very important for the prevention and treatment of both entities. Metformin, sulfonylureas, dipeptidyl peptidase-4 inhibitors, and glucagon-like peptide-1 receptor agonists should be preferred for the treatment of T2D in these patients, whereas strict targets should be avoided for the fear of hypoglycemia, falls, and fractures. Insulin should be used with caution and with careful measures to avoid hypoglycemia. Thiazolidinediones and canagliflozin should be avoided, whereas other sodium-dependent glucose transporter 2 inhibitors are less well-validated options. Insulin therapy is the preferred method for achieving glycemic control in hospitalized patients with T2D and fractures. The treatment and monitoring of osteoporosis should be continued without important amendments because of the presence of T2D.

CONCLUSIONS

Patients with coexisting T2D and osteoporosis should be managed in an optimal way according to scientific evidence.

Adjusting the 17β-Estradiol-to-Androgen Ratio Ameliorates Diabetic Nephropathy

Diabetes is manifested predominantly in males in experimental models, and compelling evidence suggests that 17β-estradiol (E2) supplementation improves hyperglycemia in humans. We previously generated a severely diabetic transgenic (Tg) mouse model by β-cell–specific overexpression of inducible cAMP early repressor (ICER) and found that male but not female ICER-Tg mice exhibit sustained hyperglycemia and develop major clinical and pathologic features of human diabetic nephropathy (DN). Thus, we hypothesized that differences in circulating hormone levels have a key role in determining susceptibility to diabetes. Here, we examined whether DN in male ICER-Tg mice is rescued by adjusting the androgen-to-E2 ratio to approximate that in normoglycemic female ICER-Tg mice. We treated hyperglycemic male ICER-Tg mice with orchiectomy (ORX), E2 pellet implantation, or both. E2 pellet implantation at an early stage of DN with or without ORX caused a rapid drop in blood glucose and a dramatic increase in β-cell number, and it markedly inhibited DN progression [namely, E2 reduced glomerulosclerosis, collagen 4 deposition and albuminuria, and prevented hyperfiltration]. Furthermore, E2 pellet implantation was more effective than ORX alone and induced a remarkable improvement, even when initiated at advanced-stage DN. In contrast, induction of normoglycemia by islet transplant in ICER-Tg mice eliminated albuminuria but was less effective than E2 + ORX in reducing glomerulosclerosis, collagen 4 deposition, and hyperfiltration. These findings indicate that E2 treatment is effective, even after establishment of DN, whereas glucose normalization alone does not improve sclerotic lesions. We propose that E2 intervention is a potential therapeutic option for DN.

RAS and sex differences in diabetic nephropathy

The incidence and progression of kidney diseases are influenced by sex. The renin-angiotensin system (RAS) is an important regulator of cardiovascular and renal function. Sex differences in the renal response to RAS blockade have been demonstrated. Circulating and renal RAS has been shown to be altered in type 1 and type 2 diabetes; this enzymatic cascade plays a critical role in the development of diabetic nephropathy (DN). Angiotensin converting enzyme (ACE) and ACE2 are differentially regulated depending on its localization within the diabetic kidney. Furthermore, clinical and experimental studies have shown that circulating levels of sex hormones are clearly modulated in the context of diabetes, suggesting that sex-dependent RAS regulation may be also be affected in these individuals. The effect of sex hormones on circulating and renal RAS may be involved in the sex differences observed in DN progression. In this paper we will review the influence of sex hormones on RAS expression and its relation to diabetic kidney disease. A better understanding of the sex dimorphism on RAS might provide a new approach for diabetic kidney disease treatment.

Raloxifene, a selective estrogen receptor modulator, is renoprotective: a post-hoc analysis

Estrogens have a protective effect on kidney fibrosis in several animal models. Here, we tested the effect of raloxifene, an estrogen receptor modulator, on the change in serum creatinine or estimated glomerular filtration rate (eGFR) and incident kidney-related adverse events. We performed a post-hoc analysis of the multiple outcomes of raloxifene evaluation trial, a double-masked, placebo-controlled randomized clinical trial encompassing 7705 post-menopausal women (aged 31-80 years) with osteoporosis. Participants were randomized to either of two doses of raloxifene, 60 or 120 mg/day, or placebo. Serum creatinine was measured at a central laboratory at baseline and annually. Adverse events were assessed every 6 months and uniformly categorized. Compared with those in the placebo group, participants on raloxifene had a slower yearly rate of increase in creatinine (significant at the low dose) and a significantly slower yearly rate of decrease in eGFR for both doses over 3 years of follow-up. Raloxifene was associated with significantly fewer kidney-related adverse events compared with placebo. Thus, treatment with raloxifene was safe and renoprotective. Clinical trials of raloxifene in post-menopausal women with kidney disease designed to look at kidney outcomes are needed to confirm these findings.

Sex, diabetes and the kidney

The incidence and the rate of progression of nondiabetic renal disease is generally greater in men compared with age-matched women, suggesting that the female sex is protective and/or that the male sex is a risk factor for the development and progression of nondiabetic renal disease. In diabetes, even though the male sex still appears to be a risk factor, this relationship is not as strong as it is in nondiabetic renal disease. Experimental evidence suggests that both estrogens and androgens play an important role in the pathophysiology of renal disease. Thus one of the potential mechanisms for the absence of a clear sex difference in the setting of diabetes may be alterations in sex hormone levels. Indeed, studies suggest that diabetes is a state of an imbalance in sex hormone levels; however, whether these changes correlate with the decline in renal function associated with diabetes is unclear. Furthermore, diabetic renal disease rarely develops before puberty, and the onset of puberty accelerates microalbuminuria, supporting the idea of the involvement of sex hormones in the development and progression of the disease. However, other than a handful of experimental studies indicating that treatment with or removal of sex hormones alters the course of diabetic renal disease, very few studies have actually directly examined the correlation between sex hormones and the disease development and progression. Further studies are necessary to determine the precise contribution of sex hormones in the pathophysiology of diabetic renal disease to develop novel and potentially sex-specific therapeutic treatments.

Estrogens and the diabetic kidney

BACKGROUND

Across all ages, the incidence and rate of progression of most nondiabetic renal diseases are markedly higher in men compared with age-matched women. These observations suggest that female sex may be renoprotective. In the setting of diabetes, however, this female protection against the development and progression of renal disease is diminished.

OBJECTIVE

This review aimed to summarize our current understanding of sex differences in the development and progression of diabetic renal disease, and of the contribution of sex hormones, particularly estrogens, to the pathophysiology of this disease. We also attempted to answer why female sex does not protect the diabetic kidney.

METHODS

Using terms such as gender, sex, diabetes, diabetic nephropathy, estrogens, and sex hormones, the PubMed database was searched for English-language articles; targeted searches were conducted using terms such as gender/sex differences in diabetic renal disease. No restrictions were imposed on publication dates.

RESULTS

Although the existing data regarding the sex differences in the incidence and progression of diabetic renal disease are inconclusive, the undisputed fact is that women with either type 1 or type 2 diabetes mellitus exhibit a much higher incidence of renal disease compared with nondiabetic women. It is conceivable that the loss of female sex as a renoprotective factor in diabetes may be related to the abnormal regulation of sex hormone concentrations. Both clinical and experimental data suggest that diabetes may be associated with an imbalance in estradiol concentrations. Supplementation with 17beta-estradiol or administration of selective estrogen receptor modulators reduces the incidence of diabetes and attenuates the progression of diabetic renal disease.

CONCLUSIONS

Serum concentrations of ovarian hormones may provide a new means for predicting future risk of renal complications in diabetes. Exogenous steroid hormones may be an effective treatment for attenuating the progression of diabetic nephropathy.

Gender and human chronic renal disease

BACKGROUND

Gender affects the incidence, prevalence, and progression of renal disease. In animal models of the disease, female sex appears to modify the course of progression. Hormonal manipulation by male or female castration also changes the course of renal disease progression, suggesting direct effects of sex hormones in influencing the course of these maladies.

OBJECTIVE

This review examines the pertinent animal and human studies assessing the role of gender, and strives to shed light on the possible physiologic mechanisms underlying the effect of gender, on renal disease progression.

METHODS

A summary and evaluation of past and recent studies describing the rate of renal disease progression in animal models and humans as it pertains to gender is provided. In addition, studies elucidating the factors involved in the more modest renal progression rate in females are reviewed and conclusions drawn. Relevant English-language publications were identified by searching the PubMed database from January 1990 until November 2007 using the search terms gender, sex, renal disease, and kidney.

RESULTS

In polycystic kidney disease, membranous nephropathy, immunoglobulin A nephropathy, and "chronic renal disease of unknown etiology," men progress at a faster rate to end-stage renal failure than do women. In type 1 diabetes mellitus, there is evidence that males are more likely to manifest signs of renal disease, such as proteinuria. The factors involved in this gender disparity may include diet, kidney and glomerular size, differences in glomerular hemodynamics, and the direct effects of sex hormones. In many, but not all, animal models of renal disease, estrogens slow progression rate. Several studies have recently evaluated the effect of selective estrogen receptor modulators on renal function in humans.

CONCLUSION

Further studies assessing the factors involved in the gender disparity in renal disease progression and the effects of hormonal treatments are warranted.