Inverse associations between androgens and renal function: the Young Men Cardiovascular Association (YMCA) study

X-chromosome and kidney function: evidence from a multi-trait genetic analysis of 908,697 individuals reveals sex-specific and sex-differential findings in genes regulated by androgen response elements

X-chromosomal genetic variants are understudied but can yield valuable insights into sexually dimorphic human traits and diseases. We performed a sex-stratified cross-ancestry X-chromosome-wide association meta-analysis of seven kidney-related traits (n = 908,697), identifying 23 loci genome-wide significantly associated with two of the traits: 7 for uric acid and 16 for estimated glomerular filtration rate (eGFR), including four novel eGFR loci containing the functionally plausible prioritized genes ACSL4, CLDN2, TSPAN6 and the female-specific DRP2. Further, we identified five novel sex-interactions, comprising male-specific effects at FAM9B and AR/EDA2R, and three sex-differential findings with larger genetic effect sizes in males at DCAF12L1 and MST4 and larger effect sizes in females at HPRT1. All prioritized genes in loci showing significant sex-interactions were located next to androgen response elements (ARE). Five ARE genes showed sex-differential expressions. This study contributes new insights into sex-dimorphisms of kidney traits along with new prioritized gene targets for further molecular research.

The role of serum testosterone and dehydroepiandrosterone sulfate in kidney function and clinical outcomes in chronic kidney disease: a systematic review and meta-analysis

OBJECTIVE/DESIGN

Testosterone might mediate sex differences in kidney function and chronic kidney disease (CKD). However, few studies analyzing the association between testosterone and kidney function showed conflicting results. Therefore, we performed a systematic review and meta-analysis.

METHODS

Six electronic databases were searched from inception to March 4, 2020, for studies that investigated the association of (i) testosterone status with kidney function in the general population or (ii) testosterone status with clinical outcomes (kidney function decline, kidney failure, cardiovascular (CV) events, and cardiovascular and all-cause mortality) in CKD patients. We used random and fixed-effect models to obtain pooled effect estimates with 95% confidence intervals (CIs).

RESULTS

No randomized-controlled trials that met the inclusion criteria were identified. One study was conducted in the general population and reported an increased risk of incident CKD with low vs normal testosterone (hazard ratio (HR): 1.38, 95% CI: 1.05;1.80). Seven studies were conducted in men with CKD and included testosterone as determinant, of which six could be meta-analyzed. Low testosterone was associated with an increased risk of all-cause mortality and CV events (pooled HR: 1.98, 95% CI: 1.36;2.89; pooled HR of 2.40, 95% CI: 1.22;4.71, respectively). Two studies showed an increased risk of all-cause mortality with decreased dehydroepiandrosterone sulfate (DHEAS) in men with CKD; results regarding CV events were conflicting.

CONCLUSIONS

Although literature is scarce, evidence suggests that lower testosterone may increase CKD risk in the general population and risk of all-cause mortality and CV events in men with CKD. Whether testosterone supplementation could prevent these potential detrimental outcomes should be determined in future intervention studies.

Associations of endogenous androgens and sex hormone-binding globulin with kidney function and chronic kidney disease

INTRODUCTION

The role of endogenous androgens in kidney function and disease has not been extensively explored in men and women.

RESEARCH DESIGN AND METHODS

We analyzed data from the observational KORA F4 study and its follow-up examination KORA FF4 (median follow-up time 6.5 years) including 1293 men and 650 peri- and postmenopausal women, not using exogenous sex hormones. We examined the associations between endogenous androgens (testosterone [T], dihydrotestosterone [DHT], free T [fT], free DHT [fDHT], and T/DHT), with estimated glomerular filtration rate (eGFR) at baseline and follow-up, prevalent, and incident chronic kidney disease (CKD) adjusting for common CKD risk factors.

RESULTS

At baseline, 73 men (5.7%) and 54 women (8.4%) had prevalent CKD. Cross-sectionally, no significant associations between androgens and kidney function were observed among men. In women, elevated T (β=-1.305, [95% CI -2.290; -0.320]) and fT (β=-1.423, [95% CI -2.449; -0.397]) were associated with lower eGFR. Prospectively, 81 men (8.8%) and 60 women (15.2%) developed incident CKD. In women, a reverse J-shaped associations was observed between DHT and incident CKD (P_non-linear=0.029), while higher fDHT was associated with lower incident CKD risk (odds ratio per 1 standard deviation=0.613, [95% CI 0.369; 0.971]. Among men, T/DHT (β=-0.819, [95% CI -1.413; -0.226]) and SHBG (P_non-linear=0.011) were associated with eGFR at follow-up but not with incident CKD. Some associations appeared to be modified by type 2 diabetes (T2D).

CONCLUSION

Suggestive associations are observed of androgens and SHBG with kidney impairment among men and women. However, larger well-phenotyped prospective studies are required to further elucidate the potential of androgens, SHBG, and T2D as modifiable risk factors for kidney function and CKD.

Low Serum Dehydroepiandrosterone Is Associated With Diabetic Kidney Disease in Men With Type 2 Diabetes Mellitus

BACKGROUND

The associations of dehydroepiandrosterone (DHEA) and dehydroepiandrosterone sulfate (DHEAS) with diabetic kidney disease (DKD) remained unclear. Thus, this cross-sectional study aimed to explore the associations of DHEA and DHEAS with the risk of DKD in patients with T2DM.

METHODS

The information of 1251 patients with T2DM were included in this study. Serum DHEA and DHEAS were quantified using liquid chromatography-tandem mass spectrometry assays. Multivariate logistic regression analyses were used to assess the associations of DHEA and DHEAS with DKD as well as high urine albumin to creatinine ratio (ACR).

RESULTS

In men with T2DM, the risk of DKD decreased with an increasing DHEA concentration after adjustment for traditional risk factors; the fully adjusted OR (95% CI) for tertile3 vs tertile1 was 0.37 (0.19-0.70; P = 0.010 for trend). Similarly, when taking high ACR as the outcome, low DHEA levels were still significantly associated with increased odds of high ACR (OR, 0.37; 95% CI, 0.19-0.72 for tertile3 vs tertile1; P = 0.012 for trend). The restricted cubic spline showed that the risk of DKD gradually decreased with the increment of serum DHEA levels (P-overall = 0.007; P-nonlinear = 0.161). DHEAS was not independently associated with the risk of DKD in men. In contrast, no significant relationships were found between DHEA and DHEAS and the risk of DKD in women (all P > 0.05).

CONCLUSIONS

In men with T2DM, low serum DHEA levels were independently related to the risk of DKD after adjustment for traditional risk factors. Our finding highlights the potential role of DHEA in the development of DKD in men with T2DM.

The impact of long-term Testosterone Therapy (TTh) in renal function (RF) among hypogonadal men: An observational cohort study

OBJECTIVES

Testosterone therapy (TTh) is the main treatment for elderly men with hypogonadism. No evidence of the long-term effectiveness of TTh on renal function is reported to date.

METHODS

In this study, we evaluated the long-term TTh of testosterone undecanoate (TU) administration on renal function parameters in 496 symptomatic hypogonadal men, with T levels ≤350 ng/dL. The treatment group (T-group) consisted of 312 patients and obtained TU 1000 mg for 12 weeks followed by 6-week intervals and for up to 8 years. The remaining 184 hypogonadal men, who opted against TTh, served as a control group (C-group). The two groups were similar in criteria prior to treatment. We evaluated renal function by calculating serum creatinine, urea, uric acid, and glomerular filtration rate (GFR) according to Mayo Clinic guidelines for 8 years. This study obeys the ethical guidelines of German medical association according to Section 15 of the Professional Code, document for AY- Ref. EK/CH/AU signed on Jun 2015.

RESULTS

During the study period, the T-group exhibited lower levels of urea (47.0 ± 11.8 to 34.0 ± 13.9 mg/dL), uric acid (6.57 ± 1.2 to 5.49 ± 1.5 mg/dL), serum creatinine (0.90 ± 0.10 to 1.12 ± 0.9 mg/dL), and higher-level in GFR (87.0 ± 12.9 to 98.0 ± 8.0 mL/min/1.73 m2), which were significant. Alternatively, the C-group exhibited an increase in their serum creatinine (1.16 ± 0.31 to 1.19 ± 0.58 mg/dL), an increase in uric acid (5.54 ± 1.2 to 5.44 ± 1.7 mg/dL), and a decrease in GFR (92.0 ± 20.1 to 87.0 ± 26.1 mL/min/1.73 m2). A total of 25 deaths (7.8%) was recorded in the T-group, among them 11 (44%) were cardiovascular. On the other hand, 28 patients (15.2%) died in C-group and all deaths (100%) were found to cardiovascular causes.

CONCLUSION

The results suggest that long-term TTh could improve renal function in hypogonadal men comparing to slight deterioration observed in patients without intervention. In addition to reduce mortality in cardiovascular patients, almost to the half.

Androgens, the kidney, and COVID-19: an opportunity for translational research

Coronavirus disease 2019 (COVID-19) has reached pandemic proportions, affecting millions of people worldwide. Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is the causative agent of COVID-19. Epidemiological reports have shown that the severity of SARS-CoV-2 infection is associated with preexisting comorbidities such as hypertension, diabetes mellitus, cardiovascular diseases, and chronic kidney diseases, all of which are also risk factors for acute kidney injury (AKI). The kidney has emerged as a key organ affected by SARS-CoV-2. AKI is associated with increased morbidity and mortality in patients with COVID-19. Male sex is an independent predictor for AKI, and an increased death rate has been reported in male patients with COVID-19 worldwide. The mechanism(s) that mediate the sex discrepancy in mortality due to COVID-19 remain(s) unknown. Angiotensin-converting enzyme (ACE)2 is the receptor for SARS-CoV-2. Alterations in the ACE-to-ACE2 ratio have been implicated in renal diseases. This perspective aims to discuss data that suggest that androgens, via alterations in the intrarenal renin-angiotensin system, impair renal hemodynamics, predisposing patients to AKI during COVID-19 infection, which could explain the higher mortality observed in men with COVID-19. Clinicians should ensure early and effective cardiometabolic control for all patients to ameliorate the compensatory elevation of ACE2 and alterations in the ACE-to-ACE2 ratio. A better understanding of the role of androgens in SARS-CoV-2-associated AKI and mortality is imperative. The kidney could constitute a key organ that may explain the sex disparities of the higher mortality and worst outcomes associated with COVID-19 in men.

Urine Metabolomics for Renal Cell Carcinoma (RCC) Prediction: Tryptophan Metabolism as an Important Pathway in RCC

Renal cell carcinoma (RCC) is the second most lethal urinary cancer. RCC is frequently asymptomatic and it is already metastatic at diagnosis. There is an urgent necessity for RCC specific biomarkers selection for diagnostic and prognostic purposes. In present study, we applied liquid chromatography-mass spectrometry (LC-MS) based metabolomics to analyze urine samples of 100 RCC, 34 benign kidney tumors and 129 healthy controls. Differential metabolites were analyzed to investigate if urine metabolites could differentiate RCC from non-RCC. A panel consisting of 9 metabolites showed the best predictive ability for RCC from the health controls with an area under the curve (AUC) values of 0.905 for the training dataset and 0.885 for the validation dataset. Separation was observed between the RCC and benign samples with an AUC of 0.816. RCC clinical stages (T1 and T2 vs. T3 and T4) could be separated using a panel of urine metabolites with an AUC of 0.813. One metabolite, N-formylkynurenine, was discovered to have potential value for RCC diagnosis from non-RCC subjects with an AUC of 0.808. Pathway enrichment analysis indicated that tryptophan metabolism was an important pathway in RCC. Our data concluded that urine metabolomics could be used for RCC diagnosis and would provide candidates for further targeted metabolomics analysis of RCC.

Sex Steroid Hormones Regulate Leptin Transcript Accumulation and Protein Secretion in 3T3-L1 Cells

Leptin is an adipokine produced by fat cells that regulates food consumption and metabolic activity. Sexual dimorphism in leptin and fat stores have been observed in humans and rodents with females having more leptin and greater levels of subcutaneous fat than males. One potential mechanism leading to this dimorphism is steroid hormone regulated synthesis of transcripts encoding leptin. Identification of direct regulatory mechanisms is difficult in animals or primary adipocytes due to these intertwined dimorphisms. We used well-characterized 3T3-L1 murine adipocytes to demonstrate that dihydrotestosterone (DHT) reduced Leptin (Lep) transcript abundance and cytosolic and secreted leptin protein. The magnitude of this effect was greatest on secreted leptin, which was decreased by DHT to 30% of the control. In contrast, 17β-estradiol significantly increased the abundance of transcripts encoding leptin and increased secreted leptin to 230% of the control. Treatment with estrogen and androgen receptor antagonists had opposite effects on Lep transcript abundance to steroid treatments, indicating that these transcriptional effects are mediated through the canonical steroid hormone signaling pathways. These results indicate that short-term treatments with steroid hormones are sufficient to alter both Lep transcript accumulation and leptin protein secretion, and may play a role in the sexual dimorphism of this adipokine.

[Andrologic consequences of chronic renal failure: State of the art for the yearly scientific report of the French National Association of Urology]

OBJECTIVE

To describe the state of the art of current knowledge regarding gonadal consequences of end-stage chronic kidney disease (CKD) and renal transplantation.

MATERIAL AND METHOD

A systematic review of the literature search was performed from the databases Medline (NLM, Pubmed) and Embase, focused on the following keywords: "chronic kidney disease"; "chronic renal failure"; "hypogonadism"; "kidney transplantation"; "testicular dysfunction"; "testosterone". Publications obtained were selected based on methodology, language, date of publication (last 10 years) and relevance. Prospective and retrospective studies, in English or French, review articles; meta-analysis and guidelines were selected and analyzed. This search found 383 articles. After reading titles and abstracts, 51 were included in the text, based on their relevance.

RESULTS

The prevalence of hypogonadism in CKD is reported between 24 % and 66 %, and decreases partially after renal transplantation. This is a hypogonadotropic hypogonadism whose pathophysiology is multifactorial, involving mainly a primitive testicular deficit, a hypothalamic-pituitary dysregulation, and an hyperprolactinemia. The consequences of this hypogonadism are not only sexual but also contribute to anemia, sarcopenia, atherosclerosis, and potentially in the progression of CKD. Hypogonadism is an independent risk factor for mortality in CKD patients.

CONCLUSIONS

CKD is frequently associated with an hypogonadism whose correction is validated only in the setting of erectile dysfunction treatment. The other benefits of the correction of hypogonadism in the CKD patients, including overall survival, needs to be evaluated.

Sex differences in hypertension-related renal and cardiovascular diseases in Italy: the I-DEMAND study

AIM

The aim of this study is to evaluate the differences in the prevalence of chronic kidney disease (CKD) and of cardiovascular risk factors and diseases between men and women participating in the Italy Developing Education and awareness on MicroAlbuminuria in patients with hyperteNsive Disease (I-DEMAND) study.

METHODS

This is an observational, cross-sectional, multicenter study aimed at assessing prevalence and correlates of CKD among Italian hypertensive patients attending out-patient referral clinics. CKD was defined as glomerular filtration rate (GFR) less than 60 ml/min per 1.73 m(2) [Modification of Diet in Renal Disease (MDRD) study equation and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation] and/or urine albumin-to-creatinine ratio of at least 2.5 mg/mmol in men and of at least 3.5 mg/mmol in women or both. Left-ventricular hypertrophy (LVH) was diagnosed by either ECG or echocardiography.

RESULTS

A total of 3558 study patients with renal data available were considered for this analysis: mean age was 61 ± 4 years and 37% had diabetes mellitus. Female patients (n = 1636, 46%) were older, with a greater prevalence of obesity and lower prevalence of smoking. The prevalence of concomitant coronary artery and peripheral artery diseases, but not of hypertension, diabetes mellitus, or heart failure, was lower in women than in men. The overall prevalence of albuminuria (21 vs. 32%; P = 0.001) and of microalbuminuria (16 vs. 23%; P = 0.001) was lower in women than in men. In women the prevalence of a reduced GFR estimated by both MDRD (33 vs. 21%; P = 0.001) and CKD-EPI equations (32 vs. 23%; P = 0.001) was higher than in men. CKD prevalence was similar in women and men (44 vs. 41%; P = 0.095 and 43 vs. 43%; P = 0.475, respectively, when MDRD and CKD-EPI eGFR estimations were used). The prevalence of LVH (diagnosed by either ECG or echocardiography) was similar in men and women (18 vs. 20%; P = 0.12).The main independent determinants of CKD were age, glycemia, uricemia, pulse pressure, hypertension duration, and previous cardiovascular diseases in men, and increasing age, glycemia, uricemia, pulse pressure, and a lower BMI in women.

CONCLUSION

Renal abnormalities are present in a significant number of female hypertensive patients attending hypertension clinics. Prevalence of reduced eGFR and of microalbuminuria, associated risk factors, and clinical conditions are different between men and women, suggesting the need to develop specific therapeutic strategies to prevent renal dysfunction and reduce associated morbidity and mortality.

The effect of dehydroepiandrosterone (DHEA) on renal function and metabolism in diabetic rats

Dehydroepiandrosterone (DHEA) is an endogenous steroid hormone involved in a number of biological actions in humans and rodents, but its effects on renal tissue have not yet been fully understood. The aim of this study is to assess the effect of DHEA treatment on diabetic rats, mainly in relation to renal function and metabolism. Diabetic rats were treated with subcutaneous injections of a 10mg/kg dose of DHEA diluted in oil. Plasma glucose and creatinine, in addition to urine creatinine, were quantified espectophotometrically. Glucose uptake and oxidation were quantified using radioactive glucose, the urinary Transforming Growth Factor β(1) (TGF-β(1)) was assessed by enzyme immunoassay, and the total glutathione in the renal tissue was also measured. The diabetic rats displayed higher levels of glycemia, and DHEA treatment reduced hyperglycemia. Plasmatic creatinine levels were higher in the diabetic rats treated with DHEA, while creatinine clearance was lower. Glucose uptake and oxidation were lower in the renal medulla of the diabetic rats treated with DHEA, and urinary TGF-β(1), as well as total gluthatione levels, were higher in the diabetic rats treated with DHEA. DHEA treatment was not beneficial to renal tissue, since it reduced the glomerular filtration rate and renal medulla metabolism, while increasing the urinary excretion of TGF-β(1) and the compensatory response by the glutathione system, probably due to a mechanism involving a pro-oxidant action or a pro-fibrotic effect of this androgen or its derivatives. In conclusion, this study reports that DHEA treatment may be harmful to renal tissue, but the mechanisms of this action have not yet been fully understood.

Stimulation of Sigma-1 receptor by dehydroepiandrosterone ameliorates hypertension-induced kidney hypertrophy in ovariectomized rats

The incidence of chronic renal disease in women increases with aging, especially after menopause, suggesting that loss of sex hormones contributes to the development and progression of renal diseases. Recent studies revealed that decreased dehydroepiandrosterone (DHEA) levels are associated with endothelial dysfunction, renal injury and increased cardiovascular mortality in postmenopausal women. We here investigate the role of DHEA, also known as Sigma-1 receptor (Sigma-1R) agonist, on kidney injury induced by pressure overload (PO) after ovariectomy (OVX) and defined mechanisms underlying its protective action. Wistar rats subjected to bilateral OVX were further treated with abdominal aortic stenosis between the right and left renal arteries. DHEA (15 and 30 mg/kg) was administered orally once a day for 14 days starting from two weeks after aortic banding. Time course study indicated that the right kidney (RK) weight-to-body weight (BW) ratio increases time-dependently from one to four weeks along with increased mean arterial blood pressure (MABP) after banding in the abdominal aorta with no change in the left kidney (LK) weight-to-BW ratio. Similarly, we found significant time-dependent decrease in Sigma-1R expression in the RK with no changes in the LK. Administration of the Sigma-1R agonist, DHEA, significantly inhibited hypertension-induced increases in the RKW-to-BW ratio and increased expression of Sigma-1R in the RK. DHEA also attenuated PO-induced disturbance of heart rate and MABP. DHEA administration significantly restored PO-induced impaired endothelial nitric oxide synthase (eNOS) activity with concomitant increased phosphorylation of eNOS (Ser1179) and Akt activity with increased phosphorylation at Ser 473 and at Thr 308 in the RK. We here documented, for the first time, the potential role of Sigma-1R to protect the kidney from PO-induced injury in ovariectomized rats. DHEA administration protects hypertension-induced kidney injury via upregulation of Sigma-1R and stimulation of Akt-eNOS signaling in ovariectomized rats.