Sex, diabetes and the kidney

Temporal and regional trends in adults with diabetics kidney disease in the US from 1999 to 2020

AIMS

We aim to analyze trends in mortality rates among adults with diabetic kidney disease (DKD) in the US from 1999 to 2020.

METHODS

We queried the Centers for Disease Control Wide-Ranging Online Data for Epidemiologic Research database for mortality statistics from 1999 to 2020 associated with DKD in adults aged ≥25 years. Age-adjusted mortality rates (AAMRs) were calculated and trends were analyzed using the Joinpoint Regression Program.

RESULTS

From 1999 to 2020, a total of 528,430 deaths were reported among adults with DKD. The mortality rates increased over time with males consistently exhibiting higher AAMR than females. NH American Indian or Alaska Native individuals had the highest AAMR, followed by NH Blacks, Hispanics, NH Whites, and NH Asians. The West region had the highest AAMR, followed by the Midwest, South, and Northeast. Rural regions had higher AAMR than urban areas, and mortality rates increased with age.

CONCLUSIONS

This study reveals notable disparities in DKD mortality rates across demographic groups and geographic regions. NH American Indians or Alaska Natives, males, elderly individuals, rural residents, and those in the West region were disproportionately affected. Understanding these trends is crucial for developing targeted interventions to reduce DKD-related mortality and address healthcare disparities.

Multiomics analysis investigating the impact of a high-fat diet in female Sprague-Dawley rats: alterations in plasma, intestinal metabolism, and microbial composition

Introduction

With improvements in living conditions, modern individuals exhibit a pronounced inclination towards a high-fat diet, largely because of its distinctive gustatory appeal. However, the association between high-fat diets and metabolic complications has largely been ignored, and metabolic diseases such as obesity and non-alcoholic fatty liver disease now constitute a major public health concern. Because high-fat diets increase the risk of metabolic diseases, a thorough investigation into the impact of high-fat diets on gut microbiota and metabolism is required.

Methods

We utilize 16S rRNA sequencing and untargeted metabolomics analysis to demonstrate that SD rats fed a high-fat diet exhibited marked alterations in gut microbiota and plasma, intestinal metabolism.

Results

Changes in gut microbiota included a decreased abundance at phylum level for Verrucomicrobiota, and a decreased abundance at genus level for Akkermansia, Ralstonia, Bacteroides, and Faecalibacterium. Additionally, significant changes were observed in both intestinal and plasma metabolite levels, including an upregulation of bile acid metabolism, an upregulation of glucose-lipid metabolism, and increased levels of metabolites such as norlithocholic acid, cholic acid, D-fructose, D-mannose, fructose lactate, and glycerophosphocholine. We also investigated the correlations between microbial communities and metabolites, revealing a significant negative correlation between Akkermansia bacteria and cholic acid.

Discussion

Overall, our findings shed light on the relationship between symbiotic bacteria associated with high-fat diets and metabolic biomarkers, and they provide insights for identifying novel therapeutic approaches to mitigate disease risks associated with a high-fat diet.

Gender Differences in the Incidence of Nephropathy and Changes in Renal Function in Patients with Type 2 Diabetes Mellitus: A Retrospective Cohort Study

Purpose

This research aims to examine and scrutinize gender variations in the incidence of diabetic nephropathy (DN) and the trajectory of renal function in type 2 diabetes mellitus (T2DM) patients.

Patients and Methods

We conducted a retrospective cohort study that enrolled 1549 patients diagnosed with T2DM from May 2015 to July 2023. We separately compared the clinical characteristics of male and female participants with and without DN. We utilized the Kaplan-Meier method to examine the cumulative incidence of DN among T2DM patients of varying genders. Hazard ratios (HR) and 95% confidence intervals (CI) were calculated using univariable and multivariable Cox proportional hazards regression analysis to evaluate the correlation between various factors and the risk of DN incidence. Multiple linear regression was utilized to investigate the relationship between ΔeGFR% and each factor. Logistic regression with cubic spline function and smooth curve fitting was employed to analyze the nonlinear link between ΔeGFR% and the risk of DN among participants of different genders.

Results

The prevalence of DN was higher in female participants (17.31%) than in male participants (12.62%), with a significant cumulative risk ratio (1.33 [1.02-1.73], P = 0.034). Multiple linear regression analysis revealed that creatinine, female gender, blood urea nitrogen, alkaline phosphatase, and total cholesterol had a significant impact on ΔeGFR% in T2DM patients, with standardized β coefficients of -0.325, -0.219, -0.164, -0.084, and 0.071, respectively. The restricted cubic spline analysis demonstrated a strong negative association between ΔeGFR% and the risk of developing DN (P < 0.001).

Conclusion

Both male and female patients with T2DM had a higher prevalence of DN over the 5-year follow-up period. However, women had a greater risk of developing DN and a faster decline in renal function compared to men.

Sex-Related Aspects in Diabetic Kidney Disease-An Update

Differences between the sexes exist in many diseases, and in most cases, being a specific sex is considered a risk factor in the development and/or progression. This is not quite so clear in diabetic kidney disease (DKD), the development and severity of which depends on many general factors, such as the duration of diabetes mellitus, glycemic control, and biological risk factors. Similarly, sex-specific factors, such as puberty or andro-/menopause, also determine the microvascular complications in both the male and female sex. In particular, the fact that diabetes mellitus itself influences sex hormone levels, which in turn seem to be involved in renal pathophysiology, highlights the complexity of the question of sex differences in DKD. The major objective of this review is to summarize and simplify the current knowledge on biological sex-related aspects in the development/progression but also treatment strategies of human DKD. It also highlights findings from basic preclinical research that may provide explanations for these differences.

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 hormone influence on female-biased autoimmune diseases hints at puberty as an important factor in pathogenesis

The majority of autoimmune diseases affect more women than men, suggesting an important role for sex hormones in regulating immune response. Current research supports this idea, highlighting the importance of sex hormones in both immune and metabolic regulation. Puberty is characterized by drastic changes in sex hormone levels and metabolism. These pubertal changes may be what forms the gulf between men and women in sex bias towards autoimmunity. In this review, a current perspective on pubertal immunometabolic changes and their impact on the pathogenesis of a select group of autoimmune diseases is presented. SLE, RA, JIA, SS, and ATD were focused on in this review for their notable sex bias and prevalence. Due to both the scarcity of pubertal autoimmune data and the differences in mechanism or age-of-onset in juvenile analogues often beginning prior to pubertal changes, data on the connection between the specific adult autoimmune diseases and puberty often relies on sex hormone influence in pathogenesis and established sex differences in immunity that begin during puberty.

Association of healthy lifestyles on the risk of hypertension, type 2 diabetes mellitus, and their comorbidity among subjects with dyslipidemia

Background

Adherence to a healthy lifestyle could reduce the risk of hypertension and diabetes in general populations; however, whether the associations exist in subjects with dyslipidemia remains unclear. This study aimed to investigate the integrated effect of lifestyle factors on the risk of hypertension, type 2 diabetes mellitus (T2DM), and their comorbidity among subjects with dyslipidemia.

Methods

In total of 9,339 subjects with dyslipidemia were recruited from the baseline survey of the Guangzhou Heart Study. A questionnaire survey and medical examination were performed. The healthy lifestyle score (HLS) was derived from five factors: smoking, alcohol drinking, diet, body mass index, and leisure-time physical activity. Odds ratios (ORs) with 95% confidence interval (95% CI) were calculated by using the logistic regression model and the multinomial logistic regression after adjusting for confounders.

Results

The prevalence of hypertension, T2DM, and their comorbidity was 47.65, 16.02, and 10.10%, respectively. Subjects with a higher HLS were associated with a lower risk of hypertension, T2DM, and their comorbidity. In comparison to the subjects with 0–2 HLS, the adjusted ORs for subjects with five HLS was 0.48 (95% CI: 0.40–0.57) and 0.67 (95% CI: 0.54–0.84) for hypertension and T2DM. Compared with subjects with 0-2 HLS and neither hypertension nor T2DM, those with five HLS had a lower risk of suffering from only one disease (OR: 0.48, 95% CI: 0.40–0.57) and their comorbidity (OR: 0.35, 95% CI: 0.26–0.47).

Conclusions

The results suggest that the more kinds of healthy lifestyle, the lower the risk of hypertension, T2DM, and their comorbidity among subjects with dyslipidemia. Preventive strategies incorporating lifestyle factors may provide a more feasible approach for the prevention of main chronic diseases.

Analysis of the Association between Metabolic Syndrome and Renal Function in Middle-Aged Patients with Diabetes

This study investigated the effects of metabolic syndrome on the estimated glomerular filtration rate in middle-aged participants with diabetes to provide basic data to enable the development of education programs for middle-aged people to prevent diabetic kidney disease. This cross-sectional descriptive study analyzed data obtained in the 2nd year of the 8th Korea National Health and Nutrition Examination Survey in 2020 and enrolled 279 participants aged 40-65 years who were diagnosed with diabetes. Multilevel stratified cluster sampling was used to improve the representativeness of the samples and the accuracy of parameter estimation. The risk factors of metabolic syndrome and the risk of elevated eGFR were analyzed using regression analysis and the correlation between the variables was determined using Pearson's correlation analysis. Middle-aged participants with diabetes whose eGFR was <90 showed a significant difference in their risk for metabolic syndrome based on sex, age, disease duration, and total cholesterol concentrations. Systolic blood pressure and waist circumference in men, and waist circumference and HDL cholesterol level in women were identified as risk factors that contribute to the increasing prevalence of metabolic syndrome.

Sex-specific differences in early renal impairment associated with arsenic, lead, and cadmium exposure among young adults in Taiwan

Exposure to a single metal has been reported to damage renal function in humans. However, information regarding the association between multiple-metal exposure and markers for early renal impairment in different sexes among the young adult Taiwanese population is scarce. We assessed the association between exposure to arsenic (As), cadmium (Cd), and lead (Pb), and early renal impairment markers using urinary microalbumin (MA), β2-microglobulin (β2MG), and N-acetyl-beta-D-glucosaminidase (NAG) by analyzing 157 young adults aged 20‒29 years, in Taiwan. Inductively coupled plasma mass spectrometry was used to determine urinary As, Cd, and Pb levels. Regression models were applied to different sex groups. The results showed that after adjusting for potential confounding factors and each metal, urinary Cd levels were significantly positively associated with urinary MA (β = 0.523, 95% CI: 0.147-0.899) and β2MG (β = 1.502, 95% CI: 0.635-2.370) in males. However, the urinary Cd level was significantly positively associated with only urinary NAG (β = 0.161, 95% CI: 0.027-0.296) in females. This study thus indicates that the effect of exposure to metals (especially Cd) on early renal impairment among young adults in Taiwan is sex-specific. Our study results could contribute toward developing early intervention programs for decreasing the incidence of renal dysfunction. Further studies are warranted to confirm our findings and clarify the potential mechanisms involved.

Association of Blood Heavy Metal Levels and Renal Function in Korean Adults

This study aimed to investigate the association between the levels of lead, mercury, cadmium, and nickel in the blood and renal function and to provide basic data for the development of health programs for the prevention of renal failure. This study included 1984 participants aged 19 and older who participated in the Korean National Health and Nutrition Examination Survey from 2019. Differences in values according to general characteristics and the estimated glomerular filtration rate (eGFR) stage were analyzed using a chi-square test, t-test, ANOVA, and the influencing factors were analyzed through multiple regression analysis. The concentrations of lead, mercury, cadmium, and nickel, and the risk of elevated eGFR were analyzed using linear regression. The correlation between the variables was determined using Pearson’s correlation analysis. Analysis of the correlation between blood lead, mercury, cadmium, and nickel levels and blood eGFR levels revealed that blood eGFR levels were significantly negatively correlated with blood lead, cadmium, and nickel levels (p ≤ 0.001). This study is significant in that it found a significant association between decreased eGFR and heavy metal levels and provided meaningful basic data on the association between heavy metals and renal function.

Intact mitochondrial substrate efflux is essential for prevention of tubular injury in a sex-dependent manner

The importance of healthy mitochondrial function is implicated in the prevention of chronic kidney disease (CKD) and diabetic kidney disease (DKD). Sex differences also play important roles in DKD. Our previous studies revealed that mitochondrial substrate overload (modeled by homozygous deletion of carnitine acetyl-transferase [CrAT]) in proximal tubules causes renal injury. Here, we demonstrate the importance of intact mitochondrial substrate efflux by titrating the amount of overload through the generation of a heterozygous CrAT-KO model (PT-CrATHET mouse). Intriguingly, these animals developed renal injury similarly to their homozygous counterparts. Mitochondria were structurally and functionally impaired in both sexes. Transcriptomic analyses, however, revealed striking sex differences. Male mice shut down fatty acid oxidation and several other metabolism-related pathways. Female mice had a significantly weaker transcriptional response in metabolism, but activation of inflammatory pathways was prominent. Proximal tubular cells from PT-CrATHET mice of both sexes exhibited a shift toward a more glycolytic phenotype, but female mice were still able to oxidize fatty acid-based substrates. Our results demonstrate that maintaining mitochondrial substrate metabolism balance is crucial to satisfying proximal tubular energy demand. Our findings have potentially broad implications, as both the glycolytic shift and the sexual dimorphisms discovered herein offer potentially new modalities for future interventions for treating kidney disease.

Diabetic nephropathy and proton pump inhibitors – Pilot case-control study

Introduction:

Methods:

Results:

Conclusion:

Therapeutic potential of pro-resolving mediators in diabetic kidney disease

Renal microvascular disease associated with diabetes [Diabetic kidney disease - DKD] is the leading cause of chronic kidney disease. In DKD, glomerular basement membrane thickening, mesangial expansion, endothelial dysfunction, podocyte cell loss and renal tubule injury contribute to progressive glomerulosclerosis and tubulointerstitial fibrosis. Chronic inflammation is recognized as a major pathogenic mechanism for DKD, with resident and circulating immune cells interacting with local kidney cell populations to provoke an inflammatory response. The onset of inflammation is driven by the release of well described proinflammatory mediators, and this is typically followed by a resolution phase. Inflammation resolution is achieved through the bioactions of endogenous specialized pro-resolving lipid mediators (SPMs). As our understanding of SPMs advances 'resolution pharmacology' based approaches using these molecules are being explored in DKD.

eIF2A-knockout mice reveal decreased life span and metabolic syndrome

Eukaryotic initiation factor 2A (eIF2A) is a 65 kDa protein that functions in minor initiation pathways, which affect the translation of only a subset of messenger ribonucleic acid (mRNAs), such as internal ribosome entry site (IRES)-containing mRNAs and/or mRNAs harboring upstream near cognate/non-AUG start codons. These non-canonical initiation events are important for regulation of protein synthesis during cellular development and/or the integrated stress response. Selective eIF2A knockdown in cellular systems significantly inhibits translation of such mRNAs, which rely on alternative initiation mechanisms for their translation. However, there exists a gap in our understanding of how eIF2A functions in mammalian systems in vivo (on the organismal level) and ex vivo (in cells). Here, using an eIF2A-knockout (KO) mouse model, we present evidence implicating eIF2A in the biology of aging, metabolic syndrome and central tolerance. We discovered that eIF2A-KO mice have reduced life span and that eIF2A plays an important role in maintenance of lipid homeostasis, the control of glucose tolerance, insulin resistance and also reduces the abundance of B lymphocytes and dendritic cells in the thymic medulla of mice. We also show the eIF2A KO affects male and female mice differently, suggesting that eIF2A may affect sex-specific pathways. Interestingly, our experiments involving pharmacological induction of endoplasmic reticulum (ER) stress with tunicamycin did not reveal any substantial difference between the response to ER stress in eIF2A-KO and wild-type mice. The identification of eIF2A function in the development of metabolic syndrome bears promise for the further identification of specific eIF2A targets responsible for these changes.

Systematic investigation of the pharmacological mechanism for renal protection by the leaves of Eucommia ulmoides Oliver using UPLC-Q-TOF/MS combined with network pharmacology analysis

Bark is the traditional medicinal component of Eucommia ulmoides Oliver (E. ulmoides). However, the demand for E. ulmoides medicinal materials seriously limits their sustainability. To alleviate resource constraints, the bioactivity of E. ulmoides leaves and its pharmacodynamic basis were investigated. In the present study, extracts of E. ulmoides leaves were found to display potential renal protective properties in rat glomerular mesangial (HBZY-1) cells treated with high levels of glucose, suggesting that they possess potential factors capable of treating diabetic nephropathy. Ultra-performance liquid chromatography tandem quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) was used to comprehensively characterize the chemical components of E. ulmoides leaves. A total of 83 possible chemical components, including 12 iridoids, 13 flavonoids, 14 lignans, 20 phenylpropanoids, 14 phenolic acids, and 10 additional components, were identified in E. ulmoides leaves. Network pharmacology was used for a preliminary exploration of the potential mechanism of action of renal protection afforded by E. ulmoides leaves towards diabetic nephropathy. The network pharmacology results were verified using a series of biological experiments. The present study provided the basis for the comprehensive development and utilization of E. ulmoides leaves and the discovery of potential drugs.

Associations Between Obesity and Kidney Disease in Chinese Men and Women With Type 2 Diabetes: A Retrospective Cohort Study

BACKGROUND

Our aim in this study was to explore the risk factors for kidney disease in Chinese men and women with type 2 diabetes (T2D) and to clarify the relationship between obesity and the risk of chronic kidney disease (CKD).

METHODS

This retrospective study included 3,194 patients with T2D. Among 2,574 T2D patients without CKD at baseline, 753 with follow-up records of at least 12 months were included in the retrospective cohort. Logistic regression and Cox regression were used to evaluate the risk for CKD in men and women. A restricted cubic spline model was used to analyze the association of body mass index (BMI) and waist circumference (WC) with CKD risk.

RESULTS

Multivariate logistic regression analysis suggested that obesity was a risk factor for T2D with CKD in men but not in women. After a median follow-up period of 2.8 years, the incidence of CKD in men with obesity was significantly higher than that in men with obesity with T2D (p=0.039), but there was no statistically significant difference between women with obesity and women without obesity with T2D (p=0.825). In the restricted cubic spline model analysis, BMI and WC were associated with CKD risk in a nonlinear fashion in males and females. The risk of CKD was higher in males with a BMI of ≥29.5 kg/m² or a WC of ≥100 cm, whereas there was no difference observed in females.

CONCLUSIONS

Obesity was strongly related to T2D with CKD in men. Male diabetes patients with obesity, especially abdominal obesity, are more likely to develop CKD.

Sex differences in the magnitude of diabetic ocular surface complications: Role of serum OGF

Diabetes is associated with dysregulation of the Opioid Growth Factor (OGF) - OGF receptor (OGFr) regulatory pathway leading to elevated OGF levels in serum and tissues. This study was designed to investigate the role of sex on the magnitude of ocular surface complications by direct comparison of male and female type 1 diabetic (T1D) rats. Male and female adult Sprague-Dawley rats were rendered T1D; a cohort of T1D male and female rats received insulin (=T1D-INS). Tear production, corneal surface sensitivity, as well as serum levels of estrogen, testosterone, OGF and OGFr were measured. Multivariate analyses were performed for correlations between sex, condition and magnitude of ocular surface alterations. Significant differences were noted in all parameters tested between male and female Normal, T1D, and T1D-INS animals over the 8-week observation period. Multivariate analyses revealed that the magnitude of complications is greater in female T1D rats and has a strong negative correlation with serum estrogen and OGF. Ocular surface complications associated with T1D have an earlier onset and greater magnitude in female T1D rats than male diabetic animals, and are related to elevated levels of OGF.

Sex Differences in Kidney Function and Metabolism Assessed Using Hyperpolarized [1-13C]Pyruvate Interleaved Spectroscopy and Nonspecific Imaging

Metabolic sex differences have recently been shown to be particularly important in tailoring treatment strategies. Sex has a major effect on fat turnover rates and plasma lipid delivery in the body. Differences in kidney structure and transporters between male and female animals have been found. Here we investigated sex-specific renal pyruvate metabolic flux and whole-kidney functional status in age-matched healthy Wistar rats. Blood oxygenation level–dependent and dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) were used to assess functional status. Hyperpolarized [1-¹³C]pyruvate was used to assess the metabolic differences between male and female rats. Female rats had a 41% ± 3% and 41% ± 5% lower absolute body and kidney weight, respectively, than age-matched male rats. No difference was seen between age-matched male and female rats in the kidney-to-body weight ratio. A 56% ± 11% lower lactate production per mL/100 mL/min was found in female rats than in age-matched male rats measured by hyperpolarized magnetic resonance and DCE MRI. Female rats had a 33% ± 11% higher glomerular filtration rate than age-matched male rats measured by DCE MRI. A similar renal oxygen tension (T2*) was found between age-matched male and female rats as shown by blood oxygenation level–dependent MRI. The results were largely independent of the pyruvate volume and the difference in body weight. This study shows an existing metabolic difference between kidneys in age-matched male and female rats, which indicates that sex differences need to be considered when performing animal experiments.

Impairment of renal steroidogenesis at the onset of diabetes

Accumulating evidence indicates the association between changes in circulating sex steroid hormone levels and the development of diabetic nephropathy. However, the renal synthesis of steroid hormones during diabetes is essentially unknown. Male Wistar rats were injected with streptozotocin (STZ) or vehicle. After one week, no changes in functional or structural parameters related to kidney damage were observed in STZ group; however, a higher renal expression of proinflammatory cytokines and HSP70 was found. Expression of Steroidogenic Acute Regulatory protein (StAR) and P450scc (CYP11A1) was decreased in STZ kidneys. Incubation of isolated mitochondria with 22R-hydroxycholesterol revealed a marked inhibition in CYP11A1 function at the medullary level in STZ group. The inhibition of these first steps of renal steroidogenesis in early STZ-induced diabetes led to a decreased local synthesis of pregnenolone and progesterone. These findings stimulate investigation of the probable role of nephrosteroids in kidney damage associated with diabetes.

Sex Differences in Biopsy-Confirmed Diabetic Kidney Disease

BACKGROUND

To investigate the association between sex differences and end-stage kidney disease (ESKD) in patients with biopsy-confirmed diabetic kidney disease (DKD).

METHOD

We performed a retrospective cohort study. A total of 336 patients with biopsy-confirmed DKD who were followed up for at least 12 months were enrolled. Baseline clinical and pathological data at the time of biopsy were collected. ESKD was defined by an estimated glomerular filtration rate of <15 ml/min/1.73 m² or initiation of renal replacement therapy. The association between sex differences and ESKD was assessed using the log-rank test and Cox regression.

RESULT

There were 239 (71%) male and 97 (29%) female patients in our cohort. Female patients had higher systolic blood pressure, total cholesterol and low-density lipoprotein cholesterol levels compared with male. There were a lower proportion of female patients in the very high risk grade according to the chronic kidney disease categories (37% of female vs. 44% of male). During a median follow-up time of 20 months, 101 (57.7%) male and 43 (44.3%) female entered into ESKD, with no significant difference by the log-rank test (P >0.05). Univariate [male: hazard ratio (HR) [95% confidence interval (CI)], 1.005, (0.702-1.439)] and multivariable ([male: HR (95%CI), 1.164, (0.675-2.007)]. Cox regression further showed that sex difference was not significantly associated with ESKD.

CONCLUSION

Female patients had the higher systolic blood pressure, total cholesterol, LDL-C, compared with male patients. However, there was no significant association observed between sex difference and ESKD in our study.

A Nomogram Model that Predicts the Risk of Diabetic Nephropathy in Type 2 Diabetes Mellitus Patients: A Retrospective Study

OBJECTIVE

To construct a novel nomogram model that predicts the risk of diabetic nephropathy (DN) incidence in Chinese patients with type 2 diabetes mellitus (T2DM).

METHODS

Questionnaire surveys, physical examinations, routine blood tests, and biochemical index evaluations were conducted on 1095 patients with T2DM from Guilin. A least absolute contraction selection operator (LASSO) regression and multivariable logistic regression analysis were used to screen out DN risk factors. A logistic regression analysis incorporating the screened risk factors was used to establish a predictive nomogram model. The performance of the nomogram model was evaluated using the C-index, an area under the receiver operating characteristic curve (AUC), calibration plots, and a decision curve analysis. Bootstrapping was applied for internal validation.

RESULTS

Independent predictors for DN incidence risk included gender, age, hypertension, medicine use, duration of diabetes, body mass index, blood urea nitrogen level, serum creatinine level, neutrophil to lymphocyte ratio, and red blood cell distribution width. The nomogram model exhibited moderate prediction ability with a C-index of 0.819 (95% confidence interval (CI): 0.783-0.853) and an AUC of 0.813 (95%CI: 0.778-0.848). The C-index from internal validation reached 0.796 (95%CI: 0.763-0.829). The decision curve analysis displayed that the DN risk nomogram was clinically applicable when the risk threshold was between 1 and 83%.

CONCLUSION

Our novel and simple nomogram containing 10 factors may be useful in predicting DN incidence risk in T2DM patients.

Sex Differences in Diabetes- and TGF-β1-Induced Renal Damage

While females are less affected by non-diabetic kidney diseases compared to males, available data on sex differences in diabetic nephropathy (DN) are controversial. Although there is evidence for an imbalance of sex hormones in diabetes and hormone-dependent mechanisms in transforming growth factor β1 (TGF-β1) signaling, causes and consequences are still incompletely understood. Here we investigated the influence of sex hormones and sex-specific gene signatures in diabetes- and TGF-β1-induced renal damage using various complementary approaches (a db/db diabetes mouse model, ex vivo experiments on murine renal tissue, and experiments with a proximal tubular cell line TKPTS). Our results show that: (i) diabetes affects sex hormone concentrations and renal expression of their receptors in a sex-specific manner; (ii) sex, sex hormones and diabetic conditions influence differences in expression of TGF-β1, its receptor and bone morphogenetic protein 7 (BMP7); (iii) the sex and sex hormones, in combination with variable TGF-β1 doses, determine the net outcome in TGF-β1-induced expression of connective tissue growth factor (CTGF), a profibrotic cytokine. Altogether, these results suggest complex crosstalk between sex hormones, sex-dependent expression pattern and profibrotic signals for the precise course of DN development. Our data may help to better understand previous contradictory findings regarding sex differences in DN.

The prevalence of diabetic chronic kidney disease in adult Greek subjects with type 2 diabetes mellitus: A series from hospital-based diabetes clinics

AIMS

To examine the prevalence of diabetic chronic kidney disease (DCKD) and its risk factors in adult Greek subjects with type 2 diabetes mellitus (T2DM) in a population from hospital-based diabetes clinics.

METHODS

This is a cross-sectional multicentre study based on data collected from Greek hospital-based diabetes clinics from June 2015 to March 2016. DCKD severity was defined according to the Kidney Disease: Improving Global Outcomes (KDIGO) 2012 guidelines. Multivariate analyses assessed the associations between DCKD and its potential risk factors.

RESULTS

Among the entire population (n = 1759), the overall prevalence of DCKD was 45% including mild, moderate and severe CKD. Older age, male gender, body-mass index, lack of exercise and diabetes duration were significantly associated with DCKD.

CONCLUSIONS

In Greece, DCKD in T2DM is highly prevalent. It is significantly associated with demographic and lifestyle parameters, as well as T2DM complications, suggesting that further efforts to prevent DCKD should be addressed to subjects with specific characteristics.

Sex differences in redox homeostasis in renal disease

Sex differences in redox signaling in the kidney present new challenges and opportunities for understanding the physiology and pathophysiology of the kidney. This review will focus on reactive oxygen species, immune-related signaling pathways and endothelin-1 as potential mediators of sex-differences in redox homeostasis in the kidney. Additionally, this review will highlight male-female differences in redox signaling in several major cardiovascular and renal disorders namely acute kidney injury, diabetic nephropathy, kidney stone disease and salt-sensitive hypertension. Furthermore, we will discuss the contribution of redox signaling in the pathogenesis of postmenopausal hypertension and preeclampsia.

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.

Kidney Transplantation in Transgender Patients

PURPOSE OF REVIEW

Kidney transplantation and gender affirmation treatments are becoming increasingly more prevalent due to advances in technology. However, there is a paucity of data regarding kidney transplantation in transgender patients. Interesting considerations must be made in this patient population, since there are many hormonal interactions with kidney function and the transplantation process.

RECENT FINDINGS

The diagnosis of estimated glomerular filtration rate (eGFR), preoperative assessment/counseling, decreased testosterone levels in a transgender male to female patient, increased estrogen/progesterone in a female to male patient, and drug side effects all have important and unique implications for kidney transplant recipients. Kidney transplantation can be safely and effectively managed in transgender patients with special considerations in eGFR calculations, mental health/lifestyle counseling, and drug interactions.

Novel associations between sex hormones and diabetic vascular complications in men and postmenopausal women: a cross-sectional study

Background

Associations between sex hormones and vascular remodeling have been extensively studied, but the results vary widely among different races and sex. We aimed to investigate whether total testosterone (TT), estrogen (E2), and dehydroepiandrosterone (DHEA) associate with macrovascular complications and diabetic kidney disease (DKD) among community-dwelling patients with diabetes.

Methods

A total of 4720 participants with type 2 diabetes were recruited from Shanghai, China. Common carotid artery (CCA) plaques and diameter were assessed by ultrasound. Cardiovascular disease (CVD) was defined by prior diagnosis of coronary heart disease, myocardial infarction or stroke. DKD was defined according to the ADA Guidelines.

Results

(1) In men, TT was negatively associated with CCA diameter (regression coefficient (β) − 0.044, 95% CI − 0.087, 0). E2 levels were positively associated with CVD and CCA plaque prevalence (OR 1.151, 95% CI 1.038, 1.277 and OR 1.13, 95% CI 1.017, 1.255, respectively). DHEA was negatively associated with CVD (OR 0.809, 95% CI 0.734, 0.893). In postmenopausal women, TT levels were negatively associated with CCA diameter (β − 0.046, 95% CI − 0.083, − 0.010) and positively associated with CVD (OR 1.154, 95% CI 1.038, 1.284). (2) In both men and postmenopausal women, TT levels were negatively associated with the albumin/creatinine ratio and DKD (β − 0.098, 95% CI − 0.154, − 0.043 and OR 0.887, 95% CI 0.790, 0.997 vs. β − 0.084, 95% CI − 0.137, − 0.031 and OR 0.822, 95% CI 0.731, 0.924, respectively) and DHEA levels were positively associated with DKD (OR 1.167, 95% CI 1.038, 1.313 vs. OR 1.251, 95% CI 1.104, 1.418, respectively).

Conclusions

Our study indicates that macrovascular complications were associated with low TT, DHEA and high E2 in men and with high TT in postmenopausal women. DKD was associated with low TT and high DHEA levels in both genders. Sex hormone replacement therapy requires careful and comprehensive consideration.

Trial registration ChiCTR1800017573, http://www.chictr.org.cn. Registered 04 August 2018

Electronic supplementary material

The online version of this article (10.1186/s12933-019-0901-6) contains supplementary material, which is available to authorized users.

Hepatitis B Vaccination Status in Chronic Kidney Disease: Experience at Pakistan Institute of Medical Sciences

Objective To know the status of vaccination against hepatitis B in chronic kidney disease patients, and to see the association of vaccination status with various factors. Materials and Methods A cross-sectional observational study was conducted in the Department of Nephrology, Pakistan Institute of Medical Sciences, Islamabad, from December 2015 to May 2016. Patients reporting in the outpatient department or admitted with the diagnosis of chronic kidney disease, whether on dialysis or not, were included in the study. Patient's information like the status of hepatitis B vaccination, age, gender, socioeconomic status, education and duration of chronic kidney disease were collected on a specially designed proforma. Results A total of 451 patients were included in the study, 57.43% were male and 42.57% were female. Mean age was 43.76±17.12 years. About 69% of the patients were from low socioeconomic class, 31% from the middle or higher middle class. Most of the patients were either uneducated (32.59%) or only had eight years of school education (33.04%). Only 19.9% of patients were vaccinated against hepatitis B virus. Conclusion Status of vaccination against hepatitis B virus in chronic kidney disease patients is not satisfactory. It is strongly associated with socioeconomic class.

Sex differences in diabetes and kidney disease: mechanisms and consequences

Type 1 and type 2 diabetes, along with their accompanying hyperglycemia, are associated with a multitude of comorbidities including the development of diabetic kidney disease. Although the hallmarks of these metabolic disorders have been well characterized in population and animal studies, it is becoming increasingly apparent that diabetes manifests itself differently in men and women. This review summarizes the recent diabetic literature with a focus on known sex differences in clinical and preclinical studies. It explores the physiological differences of glucose handling and the development of diabetes between men and women. This review also uncovers potential mechanisms for these differences, honing in on the vital role that sex hormone signaling plays in the progression of diabetes and renal complications.

Heavy metals, welding fumes, and other occupational exposures, and the risk of kidney cancer: A population-based nested case-control study in three Nordic countries

OBJECTIVES

To determine whether occupational exposure to heavy metals (chromium (VI), iron, nickel, lead) and welding fumes is associated with the risk of kidney cancer and to describe whether other occupational exposures included in the Job Exposure Matrix of the Nordic Occupational Cancer (NOCCA) study are associated with the risk.

MATERIALS AND METHODS

Nested case-control study among individuals registered in population censuses in Finland, Iceland, and Sweden in 1960-1990. A total of 59,778 kidney cancer cases, and 298,890 controls matched on sex, age, and country. Cumulative occupational exposures to metals (chromium (VI), iron, nickel, lead), welding fumes, and 24 other occupational exposure covariates, lagged 0, 10, and 20 years.

RESULTS

Overall, there was no or very little association between kidney cancer and exposures studied. The risk was elevated in individuals with high exposure to asbestos (OR 1.19, 95%CI 1.08-1.31). The risk was significantly decreased for individuals characterized with high perceived physical workload (OR 0.86, 95%CI 0.82-0.91), high exposure to ultraviolet radiation (OR 0.85, 95%CI 0.79-0.92), and high exposure to wood dust (OR 0.82, 95%CI 0.71-0.94). The risk of kidney cancer under the age of 59 was elevated in individuals with high exposure to nickel (OR 1.49, 95%CI 1.03-2.17). The risk of kidney cancer in age 59-74 years was elevated for individuals with high exposure to iron (OR 1.41, 95%CI 1.07-1.85), and high exposure to welding fumes (OR 1.43, 95%CI 1.09-1.89).

CONCLUSIONS

The only markedly elevated risks of kidney cancer were seen for the highest exposures of nickel and iron/welding fumes in specific age strata.

Lipoprotein lipase in mouse kidney: effects of nutritional status and high-fat diet

Activity of lipoprotein lipase (LPL) is high in mouse kidney, but the reason is poorly understood. The aim was to characterize localization, regulation, and function of LPL in kidney of C57BL/6J mice. We found LPL mainly in proximal tubules, localized inside the tubular epithelial cells, under all conditions studied. In fed mice, some LPL colocalized with the endothelial markers CD31 and GPIHBP1 and could be removed by perfusion with heparin, indicating a vascular location. The role of angiopoietin-like protein 4 (ANGPTL4) for nutritional modulation of LPL activity was studied in wild-type and Angptl4^-/- mice. In Angptl4^-/- mice, kidney LPL activity remained high in fasted animals, indicating that ANGPTL4 is involved in suppression of LPL activity on fasting, like in adipose tissue. The amount of ANGPTL4 protein in kidney was low, and the protein appeared smaller in size, compared with ANGPTL4 in heart and adipose tissue. To study the influence of obesity, mice were challenged with high-fat diet for 22 wk, and LPL was studied after an overnight fast compared with fasted mice given food for 3 h. High-fat diet caused blunting of the normal adaptation of LPL activity to feeding/fasting in adipose tissue, but in kidneys this adaptation was lost only in male mice. LPL activity increases to high levels in mouse kidney after feeding, but as no difference in uptake of chylomicron triglycerides in kidneys is found between fasted and fed states, our data confirm that LPL appears to have a minor role for lipid uptake in this organ.

Impact of diabetes and sex in heart failure with reduced ejection fraction patients from the ASIAN-HF registry

AIMS

To examine sex differences in clinical characteristics, echocardiographic features, quality of life and 1-year death or heart failure (HF) hospitalization outcomes in patients with/without diabetes mellitus (DM).

METHODS AND RESULTS

Utilizing the Asian Sudden Cardiac Death in HF (ASIAN-HF) registry, 5255 patients (mean age 59.6 ± 13.1, 78% men) with symptomatic HF with reduced ejection fraction (HFrEF) were stratified by DM status to address the research aims. Despite similar prevalence of DM between Asian men (43%) and women (42%), the odds of DM increased at lower body mass index in women vs. men (≥ 23 vs. ≥ 27.5 kg/m² , P_interaction  = 0.014). DM was more strongly related to chronic kidney disease in women vs. men [adjusted odds ratio (OR) 1.85, 95% confidence interval (CI) 1.33-2.57 vs. OR 1.32, 95% CI 1.11-1.56, P_interaction  = 0.009]. Sex also modified the relationship between DM and left ventricular geometry (P_interaction  = 0.003), whereby DM was associated with a more concentric left ventricular geometry in women than men. Women had lower quality of life than men (P < 0.001), in both DM and non-DM groups. DM was associated with worse composite outcomes at 1 year in women vs. men [hazard ratio (HR) 1.79, 95% CI 1.24-2.60 vs. HR 1.32, 95% CI 1.12-1.56; P_interaction  = 0.005).

CONCLUSIONS

Asian women with HFrEF were more likely to have DM despite a lean body mass index, a greater burden of chronic kidney disease and more concentric left ventricular geometry, compared to men. Furthermore, DM confers worse quality of life, irrespective of sex, and a greater risk of adverse outcomes in women than men. These data underscore the need for sex-specific approaches to diabetes in patients with HF.

Sex-Related Disparities in CKD Progression

BACKGROUND

In the United States, incidence of ESRD is 1.5 times higher in men than in women, despite men's lower prevalence of CKD. Prior studies, limited by inclusion of small percentages of minorities and other factors, suggested that men have more rapid CKD progression, but this finding has been inconsistent.

METHODS

In our prospective investigation of sex differences in CKD progression, we used data from 3939 adults (1778 women and 2161 men) enrolled in the Chronic Renal Insufficiency Cohort Study, a large, diverse CKD cohort. We evaluated associations between sex (women versus men) and outcomes, specifically incident ESRD (defined as undergoing dialysis or a kidney transplant), 50% eGFR decline from baseline, incident CKD stage 5 (eGFR<15 ml/min per 1.73 m²), eGFR slope, and all-cause death.

RESULTS

Participants' mean age was 58 years at study entry; 42% were non-Hispanic black, and 13% were Hispanic. During median follow-up of 6.9 years, 844 individuals developed ESRD, and 853 died. In multivariable regression models, compared with men, women had significantly lower risk of ESRD, 50% eGFR decline, progression to CKD stage 5, and death. The mean unadjusted eGFR slope was -1.09 ml/min per 1.73 m² per year in women and -1.43 ml/min per 1.73 m² per year in men, but this difference was not significant after multivariable adjustment.

CONCLUSIONS

In this CKD cohort, women had lower risk of CKD progression and death compared with men. Additional investigation is needed to identify biologic and psychosocial factors underlying these sex-related differences.

Effects of l-Carnitine on the Follicle-Stimulating Hormone, Luteinizing Hormone, Testosterone, and Testicular Tissue Oxidative Stress Levels in Streptozotocin-Induced Diabetic Rats

The present study was designed to investigate the antioxidant property of l-carnitine (LC) on serum levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH), testosterone (TH) and testis oxidative stress in streptozotocin (STZ)-induced diabetic rats. The rats were divided into the following groups: group I, control; group II, LC 100 mg/kg/d; group III, diabetic; and groups IV to VI, diabetic rats treated with 50, 100, and 200 mg/kg/d of LC, respectively. Daily injections were given intraperitoneally for 7 weeks. At the end of experimental period, after sacrificing the rats, FSH, LH, TH, total antioxidant capacity (TAC), malondialdehyde (MDA), glutathione (GSH), catalase (CAT), mitochondrial function (MTT), protein carbonyl (PC), and reactive oxygen species (ROS) levels were measured. STZ caused an elevation of MDA, ROS, and PC (P < .001) with reduction of GSH, CAT, TAC, and MTT (P < .001) in the serum levels. Group VI had significantly increased FSH, LH, and TH levels versus the untreated diabetic group (P < .001). Although groups V and VI significantly decreased MDA (P < .001), PC (P < .01), and ROS (P < .01) compared with the untreated diabetic group; only in group VI, the activity of GSH (P < .001), CAT (P < .01), TAC (P < .001), and MTT (P < .001) significantly increased. The results of the present study suggest that LC decreased diabetes-induced oxidative stress complications and also improved serum level of FSH, LH, and TH by reducing levels of lipid peroxidation and increasing antioxidant enzymes.

Testosterone Therapy and Glucose Homeostasis in Men with Testosterone Deficiency (Hypogonadism)

Since the early 1990s, it has been recognized that testosterone (T) levels are lower in men with type 2 diabetes mellitus (T2DM) compared with nondiabetic men (controls). Hypogonadism has been reported in approximately 50% of men with T2DM with robust correlations with measures of obesity, such as waist circumference and body mass index (BMI). In longitudinal studies, hypogonadism has been identified as a predictor of incident T2DM. Experimental withdrawal of T led to acute decreased insulin sensitivity, which can be reversed by normalization of T concentrations. Androgen deprivation therapy, commonly used in men with advanced prostate cancer, increases the risk of incident T2DM significantly.While short-term studies of T therapy in hypogonadal men with T2DM show only minor effects, long-term administration of T leads to meaningful and sustained improvements of glycemic control with parallel reductions in body weight and waist circumference. The more insulin-resistant and obese a patient is at the time of initiation of T therapy, the more improvements are noted. The observed effects are likely mediated by the increase in lean body mass invariably achieved by T therapy, as well as the improvement in energy and motivation, referred to as the psychotropic effects of T. As recommended by various guidelines, measuring T levels and, if indicated, restoring men's T levels into the normal physiological range can have a substantial impact on ameliorating T2DM in hypogonadal men.

Women and renal replacement therapy in Europe: lower incidence, equal access to transplantation, longer survival than men

In 2018, World Kidney Day (WKD) and International Women's Day coincide. The WKD editorial focuses on women's kidney health. The European Renal Association-European Dialysis and Transplant Association (ERA-EDTA) Registry Annual Report 2015 summary provides an excellent snapshot of renal replacement therapy (RRT) epidemiology and women in Europe. The WKD editorial reports a lower incidence of RRT in women in major registries and potential limitations to women's access to transplantation. What is the situation in Europe? In Europe, the incidence of RRT is also lower in women: 38% of incident RRT patients are women. Does it represent milder chronic kidney disease (CKD) in women or barriers to RRT access? The question arises from the higher prevalence of CKD Stages G3-G5 in women than in men. However, in some European countries, such as Spain, non-dialysis CKD Stages G4-G5 is less frequent in women than in men, recapitulating the difference in RRT incidence. In the ERA-EDTA Registry, the incidence of transplantation as a first modality on Day 1 was slightly higher for women and survival on RRT was similar for women and men in the first 3 months, but an intergender gap favouring women increased as RRT vintage increased. However, women on RRT are worse off regarding survival when compared with women in the general population than men on RRT compared with men in the general population. In conclusion, the ERA-EDTA Registry Annual Report 2015 and European epidemiology data suggest a lower incidence of end-stage kidney disease in women, no gender differences in access to transplantation and better RRT survival in women.

Gender Difference in the Association of Early- vs. Late-Onset Type 2 Diabetes with Non-Fatal Microvascular Disease in China: A Cross-sectional Study

BACKGROUND

This study aimed to test whether early-onset (defined as <40 years of age) type 2 diabetes mellitus (T2DM) imparted different risks of microvascular disease to Chinese men and women.

METHODS

222,537 Chinese patients with T2DM were recruited in 630 hospitals from 106 cities in 30 provinces of China in 2012 using a cross-sectional design. Logistic regression analysis was performed to obtain odds ratios (ORs) of male vs. female for diabetic retinopathy (DR) and diabetic nephropathy (DN). Additive interaction was used to test whether male gender and early-onset T2DM had interactive effects for DR and DN.

RESULTS

More men than women with T2DM had DN (4.5 vs. 3.0%, P < 0.0001), DR (5.3 vs. 5.1%, P < 0.0001), and microvascular disease (either DN or DR) (8.4 vs. 7.1%, P < 0.0001). After adjustment for age and levels of hospitals, the effect sizes of early-onset T2DM for microvascular disease were higher in men than in women, with a 2.67 [95% confidence intervals (CI): 2.51-2.85] fold risk in men and a 2.53 (95% CI: 2.35-2.72) fold risk in women. The risk effect sizes were greatly attenuated by further adjusting for diabetes durations and other traditional risk factors, with a 1.28 (95% CI: 1.19-1.37) fold risk in men and a 1.07 (95% CI: 0.99-1.16) fold risk in women. After adjustment for diabetes durations and other traditional risk factors, using women with late-onset T2DM as the reference, co-presence of early-onset and male gender significantly enhanced the ORs of either early-onset alone (1.10, 95% CI: 1.03-1.19) or male gender alone (0.96, 95% CI: 0.93-0.99) to 1.32 (95% CI: 1.24-1.41), with significant additive interaction. Kaplan-Meier analysis showed that in early-onset T2DM, DN developed 5 years earlier in men than in women.

CONCLUSION

Early-onset T2DM increased more risk of microvascular complications in Chinese men than in women, most of increased risks being attributable to longer diabetes durations.

High glucose impaired estrogen receptor alpha signaling via β-catenin in osteoblastic MC3T3-E1

Diabetic Mellitus is a risk factor for osteoporosis. It has been suggested that altered estrogen or estrogen receptor α/β (ERα/β) signaling may be involved in diabetic osteoporosis. The present study is to investigate the effects of high glucose on ERα/β signaling in osteoblastic MC3T3-E1 and how the altered signaling of ERα/β affect osteoblastic bone formation. ERα/β signaling was demonstrated as ERα/β protein expression (Western Blotting) and ER transcription activity (Luciferase Reporter assays). Proliferation (WSK-1 assaying), differentiation (ALP staining) and mineralization (Alizalard Red staining) of MC3T3-E1 were examined to evaluate bone formation function. It has been found that high glucose increased ERα/β expression dose-dependently and time-dependently, but high glucose (33mM) decreased ERα transcription activity. 17β-estradiol increased the ERα/β expression dose-dependently in normal medium, but decreased the ERα/β expression dose-dependently in medium with high glucose (33mM). High glucose decreased bone formation and also decreased the osteogenic effects of 17β-estradiol (10^-8M). High glucose decreased β-catenin expression dose-dependently and time-dependently. LiCl, an inhibitor of β-catenin degradation, decreased ERα expression but increased ERα transcription activity. When compared with high glucose treatment, LiCl (5mM) increased ALP activity and calcified nodes. Besides, high glucose also decreased the protein expression PI-3K, pAKT/AKT, GSK-3β. In conclusion, the present study suggested that high glucose may impair ERα transcription activity by inhibiting β-catenin signaling in osteoblastic MC3T3-E1, leading decreased bone formation ligand-dependently or ligand-independently.

Sex difference in the risk for exercise-induced albuminuria correlates with hemoglobin A1C and abnormal exercise ECG test findings

BACKGROUND

Albuminuria is an established marker for endothelial dysfunction and cardiovascular risk in diabetes and prediabetes. Exercise induced albuminuria (EiA) appears earlier and may be a more sensitive biomarker for renal endothelial damage. We sought to examine the association between EiA, parameters of the metabolic syndrome, A1C levels, exercise ECG test results and sex related differences in a large cohort of healthy, pre-diabetic and diabetic subjects.

METHODS

A total of 3029 participants from the Tel-Aviv Medical Center Inflammation Survey cohort (mean age 46 years, 73% men) were analyzed. Multiple physiologic and metabolic parameters including A1C were collected and albuminuria was measured in all subjects before and immediately after completing an exercise ECG test.

RESULTS

Exercise increased urinary albumin to creatinine ratio (ΔEiA) by 2.8 (0-13.6) mg/g for median (IQR) compared to rest albuminuria (p < 0.001). An increase in ΔEiA was observed with accumulating parameters of the metabolic syndrome. ΔEiA showed significant interaction with sex and A1C levels; i.e. women with A1C > 6.5% had an increased risk of higher ΔEiA (p < 0.001). Using a cutoff of ΔEiA > 13 mg/g (top quartile) we found that women with ΔEiA > 13 mg/g were at greater risk for abnormal exercise ECG findings, (OR = 2.7, p = 0.001).

CONCLUSION

Exercise promotes excessive urinary albumin excretion in dysmetabolic patients. In women, a significant correlation exists between ΔEiA and A1C levels. A cutoff of ΔEiA > 13 mg/g in women may be used to identify populations at risk for abnormal exercise ECG test findings and perhaps increased cardiovascular risk. Future studies will be needed to further validate the usefulness of ΔEiA as a biomarker for cardiovascular risk in women with and without diabetes.

Anti-fibrotic actions of relaxin

Fibrosis refers to the hardening or scarring of tissues that usually results from aberrant wound healing in response to organ injury, and its manifestations in various organs have collectively been estimated to contribute to around 45-50% of deaths in the Western world. Despite this, there is currently no effective cure for the tissue structural and functional damage induced by fibrosis-related disorders. Relaxin meets several criteria of an effective anti-fibrotic based on its specific ability to inhibit pro-fibrotic cytokine and/or growth factor-mediated, but not normal/unstimulated, fibroblast proliferation, differentiation and matrix production. Furthermore, relaxin augments matrix degradation through its ability to up-regulate the release and activation of various matrix-degrading matrix metalloproteinases and/or being able to down-regulate tissue inhibitor of metalloproteinase activity. Relaxin can also indirectly suppress fibrosis through its other well-known (anti-inflammatory, antioxidant, anti-hypertrophic, anti-apoptotic, angiogenic, wound healing and vasodilator) properties. This review will outline the organ-specific and general anti-fibrotic significance of exogenously administered relaxin and its mechanisms of action that have been documented in various non-reproductive organs such as the cardiovascular system, kidney, lung, liver, skin and tendons. In addition, it will outline the influence of sex on relaxin's anti-fibrotic actions, highlighting its potential as an emerging anti-fibrotic therapeutic.

LINKED ARTICLES

This article is part of a themed section on Recent Progress in the Understanding of Relaxin Family Peptides and their Receptors. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.10/issuetoc.

Epochs in the depressor/pressor balance of the renin-angiotensin system

The renin-angiotensin system (RAS) plays a commanding role in the regulation of extracellular fluid homoeostasis. Tigerstadt and Bergman first identified the RAS more than two centuries ago. By the 1980s a voyage of research and discovery into the mechanisms and actions of this system led to the development of drugs that block the RAS, which have become the mainstay for the treatment of cardiovascular and renal disease. In the last 25 years new components of the RAS have come to light, including the angiotensin type 2 receptor (AT2R) and the angiotensin-converting enzyme 2 (ACE2)/angiotensin-(1-7) [Ang(1-7)]/Mas receptor (MasR) axis. These have been shown to counter the classical actions of angiotensin II (AngII) at the predominant angiotensin type 1 receptor (AT1R). Our studies, and those of others, have demonstrated that targeting these depressor RAS pathways may be therapeutically beneficial. It is apparent that the evolution of both the pressor and depressor RAS pathways is distinct throughout life and that the depressor/pressor balance of the RAS vary between the sexes. These temporal patterns of expression suggest that therapies targeting the RAS could be optimized for discrete epochs in life.

Kidney disease and venous thromboembolism: Does being woman make the difference?

The risk of venous thromboembolism (VTE) is increased across the spectrum of chronic kidney disease (CKD), from mild to more advanced CKD, and typically characterizes nephrotic syndrome (NS). VTE risk in patients with kidney disease may be due to underlying hemostatic abnormalities, including activation of pro-thrombotic factors, inhibition of endogenous anticoagulation systems, enhanced platelet activation and aggregation, and decreased fibrinolytic activity. The mechanisms involved differ depending on the cause of the kidney impairment (i.e. presence of NS or CKD stage). Sex and gender differences, as well as, environmental factors or comorbidities may play a modulating role; however, specific sex and gender data on this topic are still rare. The aim of the present review is to discuss the VTE risk associated with impairment of kidney function, the potential mechanism accounting for it and the impact of sex differences in this clinical setting.

[Sex- and gender-aspects in regard to clinical practice recommendations for pre-diabetes and diabetes]

Metabolic diseases dramatically affect life of men and women from infancy up to old age and are a major challenge for clinicians. Health professionals are confronted with different needs of women and men. This article aims at an increase of gender awareness and the implementation of current knowledge of gender medicine in daily clinical practice with regard to pre-diabetes and diabetes. Sex and gender affect screening and diagnosis of metabolic diseases as well as treatment strategies and outcome. Impaired glucose and lipid metabolism, regulation of energy balance and body fat distribution are related to steroid hormones and therefore impose their influence on cardiovascular health in both men and women. Furthermore, education, income and psychosocial factors relate to development of obesity and diabetes differently in men and women. Males appear to be at greater risk of diabetes at younger age and at lower BMI compared to women, but women feature a dramatic increase of their cardiometabolic risk after menopause. The estimated future years of life lost owing to diabetes is somewhat higher in women than men, with higher increase of vascular death in women, but higher increase of cancer death in men. In women pre-diabetes or diabetes are more distinctly associated with a higher number of vascular risk factors, such as inflammatory parameters, unfavourable changes of coagulation and blood pressure. Pre-diabetic and diabetic women are at much higher relative risk for vascular disease. Women are more often obese and less physically active, but may even have greater benefit from increased physical activity than males. Whereas men predominantly feature impaired fasting glucose, women often show impaired glucose tolerance. A history of gestational diabetes or the presence of a PCOS or increased androgen levels in women, on the other hand the presence of erectile dysfunction (ED) or decreased testosterone levels in men are sex specific risk factors for diabetes development. ED is a common feature of obese men with the Metabolic Syndrome and an important predictor of cardiovascular disease. Diabetic women also feature sexual dysfunctions much more frequently than non-diabetic women which should be addressed in clinical care. Several studies showed that diabetic women reach their targets of metabolic control (HbA1c), blood pressure and LDL-cholesterol less often than their male counterparts, although the reasons for worse treatment outcome in diabetic females are not clear. Furthermore, sex differences in action, pharmacokinetics, and side effects of pharmacological therapy have to be taken into account.

Stable Isotope Labeling with Amino Acids (SILAC)-Based Proteomics of Primary Human Kidney Cells Reveals a Novel Link between Male Sex Hormones and Impaired Energy Metabolism in Diabetic Kidney Disease

Male sex predisposes to many kidney diseases. Considering that androgens exert deleterious effects in a variety of cell types within the kidney, we hypothesized that dihydrotestosterone (DHT) would alter the biology of the renal tubular cell by inducing changes in the proteome. We employed stable isotope labeling with amino acids (SILAC) in an indirect spike-in fashion to accurately quantify the proteome in DHT- and 17β-estradiol (EST)-treated human proximal tubular epithelial cells (PTEC). Of the 5043 quantified proteins, 76 were differentially regulated. Biological processes related to energy metabolism were significantly enriched among DHT-regulated proteins. SILAC ratios of 3 candidates representing glycolysis, N-acetylglucosamine metabolism and fatty acid β-oxidation, namely glucose-6-phosphate isomerase (GPI), glucosamine-6-phosphate-N-acetyltransferase 1 (GNPNAT1), and mitochondrial trifunctional protein subunit alpha (HADHA), were verified in vitro. In vivo, renal GPI and HADHA protein expression was significantly increased in males. Furthermore, male sex was associated with significantly higher GPI, GNPNAT1, and HADHA kidney protein expression in two different murine models of diabetes. Enrichment analysis revealed a link between our DHT-regulated proteins and oxidative stress within the diabetic kidney. This finding was validated in vivo, as we observed increased oxidative stress levels in control and diabetic male kidneys, compared with females. This in depth quantitative proteomics study of human primary PTEC response to sex hormone administration suggests that male sex hormone stimulation results in perturbed energy metabolism in kidney cells, and that this perturbation results in increased oxidative stress in the renal cortex. The proteome-level changes associated with androgens may play a crucial role in the development of structural and functional changes in the diseased kidney. With our findings, we propose a possible link between diabetic and non-diabetic kidney disease progression and male sex hormone levels. Data are available via ProteomeXchange (https://www.ebi.ac.uk/pride/archive/) with identifier PXD003811.

Transcriptional Profile of Kidney from Type 2 Diabetic db/db Mice

Diabetic nephropathy (DN), a common diabetic microvascular complication, is characterized by progressive glomerular sclerosis and tubulointerstitial fibrosis. However, the underlying mechanisms involved in DN remain to be elucidated. We explored changes in the transcriptional profile in spontaneous type 2 diabetic db/db mice by using the cDNA microarray. Compared with control db/m mice, the db/db mice exhibited marked increases in body weight, kidney weight, and urinary albumin excretion. Renal histological analysis revealed mesangial expansion and thickness of the basement membrane in the kidney of the db/db mice. A total of 355 differentially expressed genes (DEGs) were identified by microarray analysis. Pathway enrichment analysis suggested that biological oxidation, bile acid metabolism, and steroid hormone synthesis were the 3 major significant pathways. The top 10 hub genes were selected from the constructed PPI network of DEGs, including Ccnb2 and Nr1i2, which remained largely unclear in DN. We believe that our study can help elucidate the molecular mechanisms underlying DN.

Diabetes mellitus as a risk factor for incident chronic kidney disease and end-stage renal disease in women compared with men: a systematic review and meta-analysis

Diabetes mellitus is a strong risk factor for chronic kidney disease and end-stage renal disease. Whether sex differences in chronic kidney disease and end-stage renal disease incidence exist among diabetic patients remains unclear. This systematic review and meta-analysis was conducted to evaluate the relative effect of diabetes on chronic kidney disease and end-stage renal disease risk in women compared with men. We systematically searched Embase, PubMed, and the Cochrane Library for both cohort and case-control studies until October 2015. Studies were selected if they reported a sex-specific relationship between diabetes mellitus and chronic kidney disease or end-stage renal disease. We generated pooled estimates across studies using random-effects meta-analysis after log transformation with inverse variance weighting. Ten studies with data from more than 5 million participants were included. The pooled adjusted risk ratio of chronic kidney disease associated with diabetes mellitus was 3.34 (95 % CI 2.27, 4.93) in women and 2.84 (95 % CI 1.73, 4.68) in men. The data showed no difference in diabetes-related chronic kidney disease risk between the sexes (pooled adjusted women-to-men relative risk ratio was 1.14 [95 % CI 0.97, 1.34]) except for end-stage renal disease-the pooled adjusted women-to men relative risk ratio was 1.38 (95 % CI 1.22, 1.55; p = 0.114, I² = 38.1 %). The study found no evidence of a sex difference in the association between diabetes mellitus and chronic kidney disease. However, the excess risk for end-stage renal disease was higher in women with diabetes than in men with the same condition, from which we assume that the female gender could accelerate the disease progression. Further studies are needed to support this notion and elucidate the underlying mechanisms.

The Gomez' equations and renal hemodynamic function in kidney disease research

Diabetic kidney disease (DKD) remains the leading cause of end-stage renal disease. A major challenge in preventing DKD is the difficulty in identifying high-risk patients at an early, pre-clinical stage. Albuminuria and eGFR as measures of renal function in DKD research and clinical practice are limited by regression of one-third of patients with microalbuminuria to normoalbuminuria and eGFR is biased and imprecise in the normal-elevated range. Moreover, existing methods that are used to assess renal function do not give detailed insight into the location of the renal hemodynamic effects of pharmacological agents at the segmental level. To gain additional information about the intrarenal circulation in-vivo in humans, mathematical equations were developed by Gomez et al in the 1950s. These equations used measurements of GFR, renal blood flow (RBF), effective renal plasma flow (ERPF), renal vascular resistance (RVR), hematocrit and serum protein to calculate afferent and efferent arteriolar resistances, glomerular hydrostatic pressure and filtration pressure. Although indirect and based on physiological assumptions, these techniques have the potential to improve researchers' ability to identify early pre-clinical changes in renal hemodynamic function in patients with a variety of conditions including DKD, thereby offering tremendous potential in mechanistic human research studies. In this review, we focus on the application of Gomez' equations and summarize the potential and limitations of this technique in DKD research. We also summarize illustrative data derived from Gomez' equations in patients with type 1 (T1D) and type 2 diabetes (T2D) and hypertension.