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.

Sex Differences in Renal Function: Participation of Gonadal Hormones and Prolactin

Kidney pathophysiology is influenced by gender. Evidence suggests that kidney damage is more severe in males than in females and that sexual hormones contribute to this. Elevated prolactin concentration is common in renal impairment patients and is associated with an unfavorable prognosis. However, PRL is involved in the osmoregulatory process and promotes endothelial proliferation, dilatation, and permeability in blood vessels. Several proteinases cleavage its structure, forming vasoinhibins. These fragments have antagonistic PRL effects on endothelium and might be associated with renal endothelial dysfunction, but its role in the kidneys has not been enough investigated. Therefore, the purpose of this review is to describe the influence of sexual dimorphism and gonadal hormones on kidney damage, emphasizing the role of the hormone prolactin and its cleavage products, the vasoinhibins.

Analysis of Factors Influencing Kidney Function of Recipients After Renal Transplantation in Southwestern China: A Retrospective Study

Background: Factors influencing the kidney function of patients after renal transplantation include both recipient-related factors and donor-related factors. To gain a better understanding of these factors and to improve clinical decision-making, we performed a retrospective study of southwestern Chinese people receiving kidney transplantation.

Methods: In this retrospective analysis, a total of 2,462 recipients receiving allogeneic kidney transplantation in West China Hospital of Sichuan University from December 13, 2008 to January 10, 2018 were included. Data on recipient and donor characteristics were extracted from the Transplant Center Database and stratified by discrete time points after kidney transplantation. Univariate and multivariate logistic regression analyses were carried out on the study variables, and kidney function of postoperative patients was monitored using cystatin C (CysC) as the outcome indicator.

Results: From the univariate analysis, several factors showed statistically significant short-term impact on kidney function based on CysC after kidney transplantation, including age, ethnicity, body mass index (BMI), and HLA A-B-DR-DQ loci mismatch. Gender of recipients and gender-consistency between donors and recipients revealed both short-term and long-term influence. Younger donors had significantly better medium-and-long-term influence on kidney function. From the multivariate logistic regression analysis, recipient gender, ethnicity, BMI, and donor age were independent factors affecting postoperative CysC recovery at discrete time points.

Conclusion: Several factors of recipients related to renal function after kidney transplantation, such as gender, ethnicity, BMI and donor's age should be paid more attention to. Moreover, female and non-Han recipients decreased the risk of poor outcome during postoperative kidney function recovery while large BMI of recipients and higher donor age increased the risk. It is useful to predict the postoperative renal function earlier according to corresponding factors, and improve the patient's quality of life.

Sex-dependent mechanisms involved in renal tolerance to ischemia-reperfusion: Role of inflammation and histone H3 citrullination

Ischemia-reperfusion (I/R) injury, an inevitable result of kidney transplantation, triggers early inflammatory events that affect graft viability. Evidence from human transplantation and preclinical models of I/R suggests that a female hormonal environment positively influences the ability to recover from ischemic injury. However, the mechanisms behind these effects remain mostly unexplored. Here, we studied the influence of sex on pro-inflammatory mediators involved in the pathophysiology of acute I/R injury in male, female, and female ovariectomized (OVX) Wistar rats that underwent unilateral renal ischemia for 45 min, followed by 24 h of reperfusion. We found improved renal function, reduced cytokine expression, and decreased infiltration of myeloperoxidase-positive cells in females after I/R, when compared to their male and female OVX counterparts. Remarkably, citrullination of histone H3 was exacerbated in serum and renal tubules of females after I/R. In contrast, we observed lower levels of citrullinated histone H3 in male and female OVX rats in response to I/R, mostly in neutrophil extracellular traps. Our results demonstrate that female sex promotes renal I/R tolerance by attenuating pro-inflammatory mediators involved in I/R-induced damage.

Perioperative Considerations Regarding Sex in Solid Organ Transplantation

Sex plays a role in all stages of the organ transplant process, including listing, sex/size matching of organs, complications, graft survival, and mortality. Sex-related differences in organ transplantation are likely multifactorial related to biological and social characteristics. More information is needed to determine how sex-related differences can lead to improved outcomes for future donors and recipients of solid organs. This article provides an overview on the impact of sex on various types of solid organ transplant, including kidney, pancreas, liver, lung, and heart transplants.

Finasteride-Induced Inhibition of 5α-Reductase Type 2 Could Lead to Kidney Damage-Animal, Experimental Study

In the pharmacological treatment of prostate cancer, benign prostatic hyperplasia and androgenetic alopecia finasteride is commonly used. This drug inhibits 5α-reductase type 2, which is why finasteride affects androgen homeostasis, since testosterone (T) cannot be reduced to dihydrotestosterone (DHT). As studies on sex-related renal injuries suggest a high probability of androgen-induced renal dysfunction, the aim of this study was to determine the potential harmful effects of finasteride on the kidneys of rats. The study was performed on sexually mature male Wistar rats given finasteride. Histological sections of the kidneys were used for immunohistochemical visualization of the androgen receptor (AR), junctional proteins (occluding (Occ); E-cad, N-cad, E-/N-cadherin; β-cat, β-catenin; connexin 43 (Cx43)), proliferating cell nuclear antigen (PCNA), IL-6, and lymphocyte markers (CD3 for T cell, CD19 for B cell). The TUNEL method was used for cell apoptosis identification, and picro sirius red staining was used to assess collagen fibers thickness. The levels of T, DHT and estradiol (E2) were determined in blood serum. It was shown that finasteride treatment affected steroid hormone homeostasis, altered the expression of AR and intracellular junction proteins, changed the ratio between cell apoptosis and proliferation, and caused lymphocyte infiltration and an increase of IL-6. The thickening of collagen fibers was observed as tubular fibrosis and glomerulosclerosis. Summarizing, finasteride-induced hormonal imbalance impaired the morphology (i.e., dysplastic glomeruli, swollen proximal convoluted tubules) and physiology (changed level of detected proteins/markers expression) of the kidneys. Therefore, it is suggested that patients with renal dysfunction or following renal transplantation, with androgen or antiandrogen supplementation, should be under special control and covered by extended diagnostics, because the adverse negative effect of DHT deficiency on the progression of kidney disease cannot be ignored.

Male kidney allograft recipients at risk for urinary tract infection?

Background

Urinary tract infection (UTI) is the most common infection after renal transplantation (RTx). Although female sex is a well-known risk factor for the development of UTI after RTx, the role of the donor sex in this context remains unclear.

Methods

In this case control study 6,763 RTx cases were screened for UTI when presenting at our transplant outpatient clinics. 102 different RTx patients fulfilled the inclusion criteria and were compared to 102 controls. Data on renal function was prospectively followed for 12 months. Results were compared to a previous RTx cohort from our transplant center. Additionally, we assessed the immunological response of leukocytes from 58 kidney recipients and 16 controls to lipopolysaccharide stimulation.

Result

After identification by univariate analysis, multivariate logistic regression analysis indicated female sex, minor height, advanced age and male kidney allograft sex to be associated with the occurrence of UTI after RTx. Female recipients who received male grafts had the best renal function 12 months after presentation. However, leukocyte response of recipients to lipopolysaccharide was impaired irrespective of donor and recipient sex to the same extend.

Conclusions

We conclude from our data that male kidney allografts are associated with the occurrence of UTI after RTx but did not influence the response of leukocytes to lipopolysaccharide. Further prospective studies are needed to identify the underlying mechanisms of higher male kidney donor dependent UTI.

TFOS DEWS II Sex, Gender, and Hormones Report

One of the most compelling features of dry eye disease (DED) is that it occurs more frequently in women than men. In fact, the female sex is a significant risk factor for the development of DED. This sex-related difference in DED prevalence is attributed in large part to the effects of sex steroids (e.g. androgens, estrogens), hypothalamic-pituitary hormones, glucocorticoids, insulin, insulin-like growth factor 1 and thyroid hormones, as well as to the sex chromosome complement, sex-specific autosomal factors and epigenetics (e.g. microRNAs). In addition to sex, gender also appears to be a risk factor for DED. "Gender" and "sex" are words that are often used interchangeably, but they have distinct meanings. "Gender" refers to a person's self-representation as a man or woman, whereas "sex" distinguishes males and females based on their biological characteristics. Both gender and sex affect DED risk, presentation of the disease, immune responses, pain, care-seeking behaviors, service utilization, and myriad other facets of eye health. Overall, sex, gender and hormones play a major role in the regulation of ocular surface and adnexal tissues, and in the difference in DED prevalence between women and men. The purpose of this Subcommittee report is to review and critique the nature of this role, as well as to recommend areas for future research to advance our understanding of the interrelationships between sex, gender, hormones and DED.

Identification of patients at risk for renal impairment after living donor kidney transplantation

PURPOSE

Outcome after living donor kidney transplantation is highly relevant, since recipient and donor were exposed to notable harm. Reliable identification of risk factors is necessary.

METHODS

Three hundred sixty-six living donor kidney transplants were included in this observational retrospective study. Relevant risk factors for renal impairment 1 year after transplantation and delayed graft function were identified with univariable and multivariable binary logistic regression and ordinal regression analysis.

RESULTS

Eighty-four patients (26.6 %) suffered from renal impairment KDIGO stage ≥4 1 year post-transplant; median estimated glomerular filtration rate was 35.3 ml/min. In multivariable ordinal regression, male recipient sex (p < 0.001), recipient body mass index (p = 0.006), donor age (p = 0.002) and high percentages of panel reactive antibodies (p = 0.021) were revealed as independent risk factors for higher KDIGO stages. After adjustment for post-transplant data, recipient male sex (p < 0.001), donor age (p = 0.026) and decreased early renal function at the first post-transplant outpatient visit (p < 0.001) were identified as independent risk factors. Delayed graft function was independently associated with long stay on the waiting list (p = 0.011), high donor body mass index (p = 0.043), prolonged warm ischemic time (p = 0.016) and the presence of preformed donor-specific antibodies (p = 0.043).

CONCLUSIONS

Broadening the donor pool with non-blood related donors seems to be legitimate, although with respect to careful medical selection, since donor age in combination with male recipient sex were shown to be risk factors for decreased graft function. Warm ischemic time and waiting time need to be kept as short as possible to avoid delayed graft function. Transplantation across HLA and ABO borders did not affect outcome significantly.

Improved renal ischemia tolerance in females influences kidney transplantation outcomes

Experimentally, females show an improved ability to recover from ischemia-reperfusion injury (IRI) compared with males; however, this sex-dependent response is less established in humans. Here, we developed a series of murine renal ischemia and transplant models to investigate sex-specific effects on recovery after IRI. We found that IRI tolerance is profoundly increased in female mice compared with that observed in male mice and discovered an intermediate phenotype after neutering of either sex. Transplantation of adult kidneys from either sex into a recipient of the opposite sex followed by ischemia at a remote time resulted in ischemia recovery that reflected the sex of the recipient, not the donor, revealing that the host sex determines recovery. Likewise, renal IRI was exacerbated in female estrogen receptor α-KO mice, while female mice receiving supplemental estrogen before ischemia were protected. We examined data from the United Network for Organ Sharing (UNOS) to determine whether there is an association between sex and delayed graft function (DGF) in patients who received deceased donor renal transplants. A multivariable logistic regression analysis determined that there was a greater association with DGF in male recipients than in female recipients. Together, our results demonstrate that sex affects renal IRI tolerance in mice and humans and indicate that estrogen administration has potential as a therapeutic intervention to clinically improve ischemia tolerance.

The effect of donor-recipient gender mismatch on short- and long-term graft survival in kidney transplantation: a systematic review and meta-analysis

BACKGROUND

There is no limitation of gender matching in renal transplantation. This study was intended to evaluate its effect on short- and long-term graft survival.

METHODS

PubMed, the Web of Knowledge, Medline, the Cochrane Library, and two additional Chinese databases were searched. The data were then abstracted and meta-analyzed.

RESULTS

14 studies involving 445 279 patients were included. Each study reported data on the four gender matches (male donor-male recipient, MDMR; male donor-female recipient, MDFR; female donor-male recipient, FDMR; female donor-female recipient, FDFR). The pooled risk ratios (RRs) for 0.5-, 1-, 2-, 3-, 5-, and 10-yr graft survival rates showed that the FDMR group had the worst outcomes, and when recipients were female, short-term graft survival was worse, but long-term graft survival was better. The differences between groups changed with time.

CONCLUSIONS

FDMR patients showed poor graft survival. The female recipients had worse short-term graft survival but the best long-term graft survival. This study introduces an important consideration into donor-recipient matching in renal transplantation.

Urinary proteomic analysis of chronic allograft nephropathy

The pathogenesis of progressive renal allograft injury, which is termed chronic allograft nephropathy (CAN), remains obscure and is currently defined by histology. Prospective protocol-biopsy trials have demonstrated that clinical and standard laboratory tests are insufficiently sensitive indicators of the development and progression of CAN. The study aim was to determine if CAN could be characterized by urinary proteomic data and identify the proteins associated with disease. The urinary proteome of 75 renal transplant recipients and 20 healthy volunteers was analyzed using surface enhanced laser desorption and ionization MS. Patients could be classified into subgroups with normal histology and Banff CAN grades 2-3 with a sensitivity of 86% and a specificity of 92% by applying the classification algorithm Adaboost to urinary proteomic data. Several urinary proteins associated with advanced CAN were identified including α1-microglobulin, β2-microglobulin, prealbumin, and endorepellin, the antiangiogenic C-terminal fragment of perlecan. Increased urinary endorepellin was confirmed by ELISA and increased tissue expression of the endorepellin/perlecan ratio by immunofluoresence analysis of renal biopsies. In conclusion, analysis of urinary proteomic data has further characterized the more severe CAN grades and identified urinary endorepellin, as a potential biomarker of advanced CAN.

Orchiectomy attenuates kidney fibrosis after ureteral obstruction by reduction of oxidative stress in mice

BACKGROUND/AIMS

Men are generally more prone to chronic kidney disease and progression to end-stage renal disease than women. However, the underlying mechanisms remain unclear. In this study, we investigated the role of reactive oxygen species and testosterone in the progression of renal fibrosis in mice with unilateral ureteral obstruction (UUO).

METHODS

Mice were subjected to either orchiectomy or sham operation 14 days before either UUO or sham surgery. Harvesting of the kidney was performed 7 days after the UUO surgery to measure the production of reactive oxygen species and expression of antioxidants such as catalase, copper-zinc superoxide dismutase, and manganese superoxide dismutase, as well as fibrosis markers including α-smooth muscle actin (α-SMA) and collagen.

RESULTS

UUO resulted in increased expression of α-SMA and collagen deposition in the kidneys of both female and male mice. These increases were significantly greater in males than females. Orchiectomy significantly reduced increases in α-SMA expression and collagen deposition when compared with intact male. UUO increased the production of hydrogen peroxide and lipid peroxidation along with the decreases in expression of manganese superoxide dismutase, copper-zinc superoxide dismutase, and catalase. These changes induced by UUO were significantly attenuated by orchiectomy.

CONCLUSION

Males are more susceptible to UUO-induced kidney fibrosis compared with females, and the higher susceptibility of males is obviated by orchiectomy along with reduction in oxidative stress.

Testosterone exacerbates obstructive renal injury by stimulating TNF-alpha production and increasing proapoptotic and profibrotic signaling

Upper urinary tract obstruction is a common cause of renal dysfunction in children and adults. While there is clinical evidence of an increased male incidence and mortality rate with acute renal failure, the effect of gender and testosterone on obstructive renal injury has not previously been evaluated. We hypothesized that testosterone exacerbates proinflammatory TNF-alpha production and proapoptotic and profibrotic signaling during renal obstruction, resulting in increased apoptotic cell death and tubulointerstitial fibrosis. To study this, male, female, castrated male, and testosterone-treated oophorectomized female rats were subjected to sham operation or 3 days of unilateral ureteral obstruction (UUO). Renal cortical tissue was then analyzed for TNF-alpha production; proapoptotic caspase-8, -9, and -3 activity; apoptotic cell death; profibrotic transforming growth factor-beta1 production; and alpha-smooth muscle actin expression. In a separate arm, glomerular filtration rate (inulin clearance) was measured in rats pre- and post-UUO. Male and testosterone-treated oophorectomized female rats demonstrated a significant increase in TNF-alpha production, caspase activity, apoptotic cell death, tubulointerstitial fibrosis, and renal dysfunction during UUO compared with castrated males and normal female rats subjected to the same time course of obstruction. These results demonstrate that endogenous testosterone production in normal male rats and testosterone exogenously administered to oophorectomized females significantly increases TNF production and proapoptotic and profibrotic signaling during renal obstruction, resulting in increased apoptotic cell death, tubulointerstitial fibrosis, and renal dysfunction.

Gender differences in the renin-angiotensin and nitric oxide systems: relevance in the normal and diseased kidney

Female gender is associated with better renal function and resistance to renal injury, suggesting that an oestrogen-based effect or increased androgenic effects are responsible. Studies in rodents have confirmed a biological basis for this, based on the differential effects of androgens and oestrogens on the normal and diseased kidney. Many researchers in the field believe that the pre-menopausal levels of oestrogen are key to the protection observed in females. The key pressor effects of the renin-angiotensin (RA) system are due to both direct vasoconstrictory properties and alterations in renal control of extracellular fluid volume. Additionally, the RA has been shown to promote diverse aspects of renal injury. RA activity is positively modulated by androgens and antagonized by oestrogens. Nitric oxide (NO) is a potent vasorelaxant with a key role in renal control of extracellular fluid homeostasis. NO can variously have both protective and deleterious effects on renal injury. Endogenous oestrogen has an anti-hypertensive effect as well as protective effects against cell and organ damage, many of which are mediated via increases in NO generation. We examine how the RA- and NO-generating systems may underpin key aspects of gender differences in normal renal function and renal disease.

Gender differences in renal nuclear receptors and aryl hydrocarbon receptor in 5/6 nephrectomized rats

This study was aimed at delineating molecular pathways essential in gender-different pathogenesis of chronic kidney diseases (CKD). Renal transcripts of nuclear receptors and metabolic enzymes in male and female kidneys from 5/6 nephrectomized (Nx) rats 7 weeks post-Nx were examined using branched DNA signal amplification assay. Nx-males had marked kidney injury coupled with anemia and malnutrition. Nx-females had moderate renal injury, and were free of albuminuria, anemia, and malnutrition. Nx-males had systemic and renal inflammation, which were largely absent in Nx-females. Blood 17beta-estradiol, testosterone, and corticosterone did not change, whereas urinary testosterone decreased in both genders. Compared to males, female kidneys had higher androgen receptor (AR) and aryl hydrocarbon receptor (AhR) but lower estrogen receptor alpha (ERalpha). Compared to Nx-males, female remnant kidneys had less decreases in ERalpha and peroxisome proliferator-activated receptor alpha (PPARalpha), had no induction of AR and decrease of acyl-CoA oxidase, whereas had induction of cytochrome P450 4a1 (Cyp4a1) but decrease of AhR. Renal protein expression of a 52-kDa isoform of Wilm's tumor 1 (WT1), transcription factor critical in nephrogenesis, decreased dramatically in Nx-males but largely preserved in Nx-females. In conclusion, gender divergences in basal expression and alteration of ERalpha, AR, AhR, WT1, and PPARalpha/Cyp4a1 during CKD may explain gender differences in CKD progression and outcome of renal transplantation.

17beta-Estradiol supplementation reduces tubulointerstitial fibrosis by increasing MMP activity in the diabetic kidney

We previously reported that supplementation with 17beta-estradiol (E2) attenuates albuminuria, glomerulosclerosis, and tubulointerstitial fibrosis in diabetic nephropathy. The present study examined the mechanisms by which E2 regulates extracellular matrix (ECM) metabolism, a process that contributes to the development of glomerulosclerosis and tubulointerstitial fibrosis. The study was performed in female nondiabetic (ND), streptozotocin-induced diabetic (D), and diabetic with E2 supplementation (D+E2) Sprague-Dawley rats for 12 wk. Diabetes was associated with an increase in the renal expression of collagen alpha type IV [ND, 0.22 +/- 0.02; D, 0.99 +/- 0.09 relative optical density (ROD); P < 0.05] and fibronectin protein (ND, 0.36 +/- 0.08; D, 1.47 +/- 0.08 ROD; P < 0.05), as measured by Western blot analysis. E2 supplementation partially attenuated this increase in collagen alpha type IV (D+E2, 0.47 +/- 0.10 ROD) and fibronectin (D+E2, 0.71 +/- 0.16 ROD) protein expression associated with D. Diabetes was also associated with a decrease in the expression of matrix metalloproteinase (MMP) isoform MMP-2 (ND, 0.79 +/- 0.01; D, 0.62 +/- 0.06 ROD; P < 0.05) and MMP-9 protein (ND, 0.49 +/- 0.02; D, 0.33 +/- 0.03 ROD; P < 0.05). E2 supplementation restored MMP-2 and MMP-9 protein to levels similar or even greater than in the ND kidneys (MMP-2, 0.75 +/- 0.06; MMP-9, 0.73 +/- 0.01 ROD). The activities of MMP-2 (ND, 7.88 +/- 0.44; D, 5.60 +/- 0.54 ROD; P < 0.05) and MMP-9 (ND, 29.9 +/- 1.8; D, 12.9 +/- 2.3 ROD; P < 0.05), as measured by zymography, were also decreased with D. E2 supplementation restored MMP-2 and MMP-9 activity to levels similar to that in ND kidneys (MMP-2, 7.66 +/- 0.35; MMP-9, 21.4 +/- 2.9 ROD). We conclude that E2 supplementation is renoprotective by attenuating glomerulosclerosis and tubulointerstitial fibrosis by reducing ECM synthesis and increasing ECM degradation.

Sex differences and the role of sex steroids in renal injury

PURPOSE

There is growing evidence that significant sex differences exist in the response of the kidney to injury. In this review we explored the cumulative clinical knowledge and experimental evidence of this phenomenon.

MATERIALS AND METHODS

The current clinical evidence of increased male susceptibility to acute and chronic renal injury, and experimental data elucidating potential mechanisms of this phenomenon were reviewed.

RESULTS

Renal damage induced by nephron reduction, patient age and renal ischemia is tolerated differently by the sexes. Sex differences in disease susceptibility have historically been attributed to the protective effects of estrogen but recent evidence suggests that male hormones also have an important role in these differences. Vascular mediators, such as endothelin, nitric oxide and angiotensin II, appear to be influenced by sex and sex steroids. Additionally, inflammatory mediators, such as transforming growth factor-beta1, tumor necrosis factor-alpha and p38 mitogen activating protein kinase, similarly show differential expression and activity based on sex and the presence of sex steroids. These mediators have a significant impact on the kidney response to inflammation and injury.

CONCLUSIONS

Greater understanding of the specific role of sex steroids in renal injury may provide new therapeutic strategies to protect against inflammatory injury and renal damage in the future.

Gender hormones and the progression of experimental polycystic kidney disease

BACKGROUND

Male gender is a risk factor for progression of autosomal-dominant polycystic kidney disease (ADPKD), clinically and in the Han:SPRD rat model. Orchiectomy limits progression, but mechanisms of the detrimental effect of androgen, and/or beneficial effects of estrogen, are not known. This protocol tested the hypothesis that male gender (intact androgen status) promotes progression, while female gender (intact estrogen status) is protective; and that these disease-modifying effects are due to changes in expression of known fibrotic mediators.

METHODS

Studies were performed in male and female noncystic control (+/+) and cystic (+/-) rats subjected to orchiectomy, ovariectomy, or sham operation. At 12 weeks of age, renal function was measured. Blood and kidneys were taken for measurement of plasma and renal renin, endothelin (ET-1), endothelial nitric oxide synthase (eNOS), and vascular endothelial growth factor (VEGF), using biochemical, protein expression, and immunohistochemical methods.

RESULTS

Cystic male rats exhibited significantly reduced glomerular filtration (GFR) and effective renal plasma flow (ERPF) rates, with suppression of plasma and renal renin, up-regulation of renal ET-1 and eNOS, and down-regulation of renal VEGF expression. Orchiectomy attenuated the fall in GFR and ERPF, while numerically limiting changes in eNOS and VEGF. Female rats exhibited less cystic growth, with normal renin status, lesser elevation of renal ET-1, and proportionately lesser changes in VEGF and eNOS. Ovariectomy led to higher blood pressure and reduced GFR and ERPF, with a trend toward upregulation of ET-1, and significant down-regulation of VEGF and eNOS.

CONCLUSION

Female gender is protective, but ovariectomy attenuates the protective effect of female gender, in association with changes in renal expression of ET-1, VEGF, and eNOS. The accelerated disease in male rats can be attenuated by orchiectomy and consequent changes in expression of disease mediators.

Free Androgen Index Is Superior to Total Testosterone for Short-Term Assessment of the Gonadal Axis after Renal Transplantation

OBJECTIVE

Recent studies have assessed gonadal function in association with different immunosuppressive drugs in transplanted patients mainly relying on the measurement of total testosterone. It is the aim of this study to assess the short-term changes of the hypothalamic-pituitary-gonadal axis following renal transplantation using the free androgen index (FAI).

PATIENTS AND METHODS

The sequential changes in total testosterone, sex hormone-binding globulin (SHBG), gonadotropin and prolactin concentrations were measured in 22 male patients before and after 1-3 days, and 1, 2 and 3 weeks following renal transplantation.

RESULTS

Total testosterone and SHBG concentrations dropped significantly after transplantation (total testosterone: baseline: 15.2 +/- 1.6 nmol/l vs. 1 week: 7.9 +/- 0.8 nmol/l vs. 2 weeks: 9.8 +/- 0.9 nmol/l, SHBG: baseline: 29.9 +/- 3.2 nmol/l vs. 1 week: 19.9 +/- 2.1 nmol/l, 2 weeks: 18.9 +/- 2.4 nmol/l, p < 0.01). FAI decreased significantly after day 1-3 returning to values near baseline thereafter (baseline: 60 +/- 9% vs. day 1-3: 38 +/- 6%, 2 weeks: 61 +/- 7%; p < 0.01). There was a significant positive correlation between FAI and renal function.

CONCLUSION

Measurement of the free androgen index is superior to total testosterone for assessment of the pituitary-gonadal axis in the first weeks after renal transplantation.

Effects of progesterone and selective oestrogen receptor modulators on chronic allograft nephropathy in rats

BACKGROUND

We recently demonstrated that oestrogens ameliorate the progression of chronic allograft nephropathy (CAN). In our present study, we investigated the role of progesterone and selective oestrogen receptor modulators (SERMs) in this process.

METHODS

Female Fisher (F344) kidneys were orthotopically transplanted into intact or ovariectomized female Lewis recipients. Ovariectomized recipients were divided into four groups and were treated with either progesterone alone or in combination with oestradiol, oestradiol alone or vehicle. Intact recipients were divided into three groups and were treated with SERMs such as tamoxifen and one of its new derivatives, droloxifene or vehicle. Animals were harvested 24 weeks after transplantation for histological and immunohistological studies as well as for molecular analysis.

RESULTS

Administration of progesterone resulted in increased urinary protein excretion as well as profound glomerulosclerosis and mononuclear cell infiltration. The combined treatment had similar detrimental effects on the development of CAN. In contrast, oestradiol treatment alone improved graft function, reduced glomerulosclerosis and diminished cellular infiltration. SERMs again impaired allograft function and promoted the development of CAN. Renal allograft damage paralleled intragraft mRNA expression of transforming growth factor-beta1 in all groups.

CONCLUSIONS

Our results suggest that addition of progesterone diminishes the beneficial effects of oestrogens on the development of CAN in rats. Similarly to progesterone, SERMs worsened long-term renal allograft outcome.

Selective estrogen receptor modulators prevent neointima formation after vascular injury

Exploitation of estrogen's vasculoprotective properties in drug design is difficult due to its adverse effects on endometrium and breast. Selective estrogen receptor modulators (SERM) act as estrogen agonists in some tissues but are anti-estrogenic in others. We investigate here whether tamoxifen, raloxifene, and two novel SERMs, ospemifene and fispemifene, preserve estrogen's beneficial effects on the ovariectomized rat vascular wall, and correlate their effects with natural estrogen (17beta-E2) and a pure anti-estrogen ICI 182,780. All compounds dose-dependently (0.0025-25 mg/kg/day) inhibited neointimal thickening at 7 days after aorta denudation injury. At 28 days, tamoxifen and ospemifene (2.5 mg/kg/day) reduced intimal nuclei number and intimal area equal to 17beta-E2, while raloxifene and fispemifene had no effect. Replacing the drug at 14 days with vehicle did not induce any rebound effect at 28 days, and furthermore, resulted in a smaller neointima with raloxifene and fispemifene. 17beta-E2 and the SERMs also significantly enhanced reendothelialization. All compounds inhibited replication and all but fispemifene inhibited migration of vascular SMC and cells from cultured aortic explants in vitro. Finally, only 17beta-E2 increased the weight of the uterus above that of normal rats. Interestingly, ICI 182,780 also weakly inhibited neointima formation and SMC proliferation at 7 days, suggesting that non-estrogen receptor mediated effects may have also played a role. In conclusion, SERMs have beneficial estrogen agonist effects in the injured vascular wall through their regulation of vascular SMC function and reendothelialization. Early intervention is of particular importance in preventing the injury-response.

Estrogen regulates insulin-like growth factor 1, platelet-derived growth factor A and B, and their receptors in the vascular wall

BACKGROUND

Peptide growth factors induce vascular smooth muscle cell (SMC) proliferation and migration after vascular injury, leading to arterial stenosis. Estrogen provides vasculoprotective effects by regulating endothelial and vascular SMC function.

METHODS

We performed aortic denudations in male Wistar rats. One group received 17beta-estradiol, 0.25 mg/kg per day subcutaneously, and the other group vehicle. Growth factor and receptor mRNA in the aorta wall was quantitated at 15 minutes, 3 days, and 7 days after denudation. Western blotting and immunohistochemistry were used to quantify and localize the protein.

RESULTS

Aortic injury caused SMC proliferation in the intima and media, indicated by an increase in the number of intimal nuclei and area. Quantitative reverse-transcriptase polymerase chain reaction and Western blotting showed concomitant up-regulation of insulin-like growth factor (IGF)-1, platelet-derived growth factor (PDGF)-B, and PDGF-receptor (R)alpha. 17beta-estradiol significantly inhibited SMC proliferation and intimal thickening. Similarly, estrogen administration completely suppressed IGF-1 mRNA (P=0.004) and protein but had no effect on IGF-1R. Estrogen had virtually no effect on PDGF-A mRNA or protein levels; however, on day 7, it inhibited PDGF-Ralpha mRNA by 74% (P=0.005) and protein by 67%. On day 7, it also inhibited PDGF-B mRNA expression by 36% (P=0.04) but had little effect on protein. PDGF-Rbeta expression was unaffected by estrogen. Estradiol treatment reduced immunoreactivity of IGF-1, PDGF-A, PDGF-Ralpha, and PDGF-B in vascular lesions, whereas no changes were seen with respect to IGF-1R and PDGF-Rbeta.

CONCLUSIONS

Our findings demonstrate that estrogen regulates IGF-1, PDGF-A, PDGF-B, and PDGF-Ralpha, which may be related to the vasculoprotective effect of estrogen, but has no effect on IGF-1R or PDGF-Rbeta.