Estrogens and the diabetic kidney

Women's health and kidney protective medications

PURPOSE OF REVIEW

We discuss the sex-based differences in the pharmacokinetics and pharmacodynamics of kidney protective medications and their implications on women's health.

RECENT FINDINGS

A critical examination of adverse drug reactions highlights the underrepresentation of women in clinical trials for kidney and cardiovascular protective drugs, such as SGLT2 inhibitors, ACE inhibitors, and endothelin receptor antagonists. This underscores the need for sex-specific analyses in clinical studies to accurately assess medication efficacy and safety.

SUMMARY

The research demonstrates that women are more likely to experience adverse events and less likely to benefit from certain treatments, emphasizing the urgent need for healthcare providers to adopt a sex-informed approach in prescribing practices. Future research should prioritize sex differences from the outset to enhance understanding and improve clinical outcomes for women with chronic kidney disease and cardiovascular conditions.

Whole transcriptome mapping reveals the lncRNA regulatory network of TFP5 treatment in diabetic nephropathy

BACKGROUND

TFP5 is a Cdk5 inhibitor peptide, which could restore insulin production. However, the role of TFP5 in diabetic nephropathy (DN) is still unclear.

OBJECTIVE

This study aims to characterize the transcriptome profiles of mRNA and lncRNA in TFP5-treated DN mice to mine key lncRNAs associated with TFP5 efficacy.

METHODS

We evaluated the role of TFP5 in DN pathology and performed RNA sequencing in C57BL/6J control mice, C57BL/6J db/db model mice, and TFP5 treatment C57BL/6J db/db model mice. The differentially expressed lncRNAs (DElncRNAs) and mRNAs (DEmRNAs) were analyzed. WGCNA was used to screen hub-gene of TFP5 in treatment of DN.

RESULTS

Our results showed that TFP5 therapy ameliorated renal tubular injury in DN mice. In addition, compared with the control group, the expression profile of lncRNAs in the model group was significantly disordered, while TFP5 alleviated the abnormal expression of lncRNAs. A total of 67 DElncRNAs shared among the three groups, 39 DElncRNAs showed a trend of increasing in the DN group and decreasing after TFP treatment, while the remaining 28 showed the opposite trend. DElncRNAs were enriched in glycosphingolipid biosynthesis signaling pathways, NF-κB signaling pathways, and complement activation signaling pathways. There were 1028 up-regulated and 1117 down-regulated DEmRNAs in the model group compared to control group, and 123 up-regulated and 153 down-regulated DEmRNAs in the TFP5 group compared to the model group. The DEmRNAs were involved in PPAR and MAPK signaling pathway. We confirmed that MSTRG.28304.1 is a key DElncRNA for TFP5 treatment of DN. TFP5 ameliorated DN maybe by inhibiting MSTRG.28304.1 through regulating the insulin resistance and PPAR signaling pathway. The qRT-PCR results confirmed the reliability of the sequencing data through verifying the expression of ENSMUST00000211209, MSTRG.31814.5, MSTRG.28304.1, and MSTRG.45642.14.

CONCLUSION

Overall, the present study provides novel insights into molecular mechanisms of TFP5 treatment in DN.

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.

Correlation of Urinary Neutrophil Gelatinase with the Histopathological Extent of Kidney Damage in Patients with Diabetic Nephropathy

Diabetic nephropathy (DN), a leading cause of chronic kidney disease, is known to develop in around 40% of patients with diabetes. NGAL, a biomarker expressed by the tubular epithelium, has been evaluated in both acute and chronic kidney injury. However, kidney damage revealed by the histology of renal tissue core biopsies has not been quantified by morphometry and its correlation with urinary NGAL (uNGAL) has not been studied. Our objective was to compare levels of uNGAL with the extent of kidney damage in the histopathological results of morphometry in patients with DN. This prospective analytical study was conducted in a tertiary hospital. Urine samples of 42 patients were collected and freeze-dried. uNGAL was estimated through a chemiluminescent microparticle immunoassay. Pearson's correlation coefficients between kidney damage quantified by morphometry and NGAL values were examined. The correlation of uNGAL with the percentage of acute tubular injury assessed by morphometry in the renal core was 7.35% (P = 0.64). uNGAL had the highest correlation with inflammation (r = 54.2%; P = 0.002). Another parameter with a significant correlation was glomerular sclerosis with r = 35.6% (95% confidence interval: 10%-60%) and an associated P = 0.02. UNGAL was strongly correlated with inflammatory kidney damage in patients with DN.

Selective Modulation of the Keratoconic Stromal Microenvironment by FSH and LH

Keratoconus (KC) affects the corneal structure, with thinning and bulging outward into a conelike shape. Irregular astigmatism and decreased visual acuity appear during puberty and progress into the mid-30s, with unpredictable disease severity. The cause of KC is recognized as multifactorial, but remains poorly understood. Hormone imbalances are a significant modulator of the onset of KC. This study sought to investigate the role of gonadotropins, follicle-stimulating hormone (FSH), and luteinizing hormone (LH) in KC, using a three-dimensional, self-assembled matrix in vitro model. Healthy corneal fibroblasts and human KC cells in the corneal stroma were isolated, cultured, and stimulated with stable vitamin C to promote extracellular matrix assembly. Cultures were further stimulated with 2.5 or 10 mIU/mL FSH and 5 or 35 mIU/mL LH. Samples were evaluated for cell proliferation and morphology via BrdU assay and imaging; protein expression was assessed via Western blot analysis. Proliferation was significantly greater in human KC cells compared to healthy corneal fibroblasts with LH stimulation, but no changes were found with FSH stimulation. Additionally, in sex hormone receptors, fibrotic markers, proteoglycans, and members of the gonadotropin signaling pathway were significantly changed, largely driven by exogenous LH. The impact of exogenous FSH/LH in the KC stromal microenvironment was demonstrated. These results highlight the need to further examine the role of FSH/LH in KC and in human corneal homeostasis.

Development of diabetic macular oedema shows associations with systemic medication - An epidemiological study

PURPOSE

To identify associations between systemic drugs and the incidence of diabetic macular oedema (DME). Of interest was to find beneficial and/or deleterious associations of used drugs.

METHODS

A historic cohort design based on administrative data. Study population consisted of 150 353 individuals with diabetes. Endpoint event was the development of DME (ICD-10 H36.01), censoring events were death or study end December 2017. The follow-up started between 1997 and 2010. The systemic medication consisted of 95 substances. We constructed a nested case-control study design comparing 2630 cases with DME to 13 144 age- and sex-matched controls without DME. Results are reported as odds ratios (ORs) with 95% confidence intervals (CIs) based on conditional logistic regression models.

RESULTS

Incidence rate for DME was 1.80 per 1000 person-years (95% CI 1.73-1.87). In all, we observed a lower incidence rate of DME in females (IRR 0.57; 95% CI 0.52-0.62) compared to males. Exposure to hormone replacement therapy estradiol (OR 0.42; 0.25-0.68), temazepam (0.23; 0.08-0.62) and allopurinol (0.61; 0.43-0.86) were associated with lower risk of DME, while use of insulin or insulin analogue (3.30; 2.99-3.64), sulfonylureas (1.21; 1.05-1.40), diuretic furosemide (1.90; 1.61-2.24), calcium channel blocker amlodipine (1.53; 1.34-1.75), ACE inhibitors ramipril (1.66; 1.46-1.89) and enalapril (1.38; 1.16-1.64) were associated with an increased risk of DME.

CONCLUSIONS

Large-scale studies examining the incidence of DME are lacking. Our findings suggest that associations of systemic medications with the incidence of DME may shed light on the pathogenesis of complex DME, encouraging further studies.

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

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

Role of Sex Hormones in Prevalent Kidney Diseases

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

Identification and validation of immune-related biomarkers and potential regulators and therapeutic targets for diabetic kidney disease

BACKGROUND

Diabetic kidney disease (DKD) is a major complication of diabetes and the leading cause of end-stage renal disease worldwide. Renal inflammation and infiltration of immune cells contribute to the development and progression of DKD. Thus, the aim of the present study was to identify and validate immune-related biomarkers and analyze potential regulators including transcription factors (TFs), microRNAs (miRNAs), and drugs for DKD.

METHODS

Immune-related genes from the ImmPort database and glomeruli samples from GSE1009 and GSE30528 were used to identify differentially expressed immune-related genes (DEIRGs) of DKD. The expression level and clinical correlation analyses of DEIRGs were verified in the Nephroseq database. Murine podocytes were cultured to construct the high glucose-induced podocyte injury model. The reliability of the bioinformatics analysis was experimentally validated by RT-qPCR in podocytes. Networks among DEIRGs, regulators, and drugs were constructed to predict potential regulatory mechanisms for DKD.

RESULTS

DKD-associated DEIRGs were identified. CCL19 and IL7R were significantly upregulated in the DKD group and negatively correlated with glomerular filtration rate (GFR). GHR, FGF1, FYN, VEGFA, F2R, TGFBR3, PTGDS, FGF9, and SEMA5A were significantly decreased in the DKD group and positively correlated with GFR. RT-qPCR showed that the relative mRNA expression levels of GHR, FGF1, FYN, TGFBR3, PTGDS, FGF9, and SEMA5A were significantly down-regulated in the high glucose-induced podocyte injury group. The enriched regulators for DEIRGs included 110 miRNAs and 8 TFs. The abnormal expression of DEIRGs could be regulated by 16 established drugs.

CONCLUSIONS

This study identified immune-related biomarkers, regulators, and drugs of DKD. The findings of the present study provide novel insights into immune-related diagnosis and treatment of DKD.

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.

Single and combined effect of bisphenol A with high sucrose diet on the diabetic and renal tubular dysfunction phenotypes in Drosophila melanogaster

In the present study, effect of exposure of bisphenol A (BPA) and combined exposure of BPA + HSD has been investigated on the glucose homeostasis and associated renal complications in Drosophila. Exposure of 1.0 mM BPA alone induced type 2 diabetes like condition (T2D) in adult male D. melanogaster via oxidative stress. Elevated TGF-β signaling was evident by increased expression of baboon (babo) in BPA exposed organism that stimulated the modulation of extracellular matrix (ECM) component collagen IV resulting in the fibrosis of the Malpighian tubules (MTs). Combined exposure of BPA + HSD (high sucrose diet) resulted in the increased magnitude of T2D and MTs dysfunction parameters. Taken together, the study illustrates that BPA has diabetogenic potential in exposed Drosophila that caused adverse effects on their MTs and combined exposure with BPA and HSD could aggravate the renal tubular dysfunction. The study further suggests the use of Drosophila model to study the environmental chemicals induced diabetes mediated renal dysfunction.

Incidence rate patterns, cumulative incidence, and time trends for moderate and severe albuminuria in individuals diagnosed with type 1 diabetes aged 0-14 years: a population-based retrospective cohort study

BACKGROUND

The incidence and temporal trends of moderate and severe albuminuria during recent decades are poorly described in type 1 diabetes. We aimed to assess diabetes duration-specific incidence rates, cumulative incidence, and secular trends of albuminuria in type 1 diabetes in Finland.

METHODS

We conducted a population-based, retrospective cohort study of a stratified random sample (n=1500) of all individuals diagnosed with type 1 diabetes before age 15 years during 1970-99 in Finland. The sampling frame was the database of the Finnish Institute for Health and Welfare. Individuals with an atypical clinical course, presentation of non-diabetic kidney disease, insufficient albumin excretion rate measurements, or unavailable medical records were excluded (final sample n=1430). Study participants were followed up until death, the event of interest (moderate or severe albuminuria or kidney failure), or the most recent event-free date. Medical records retrieved up to Dec 31, 2020 were systematically reviewed for albuminuria determinations. Moderate and severe albuminuria were categorised on the basis of international reference limits (two of three consecutive urine samples). Kidney failure was defined as dialysis treatment or kidney transplant. Cohorts defined by calendar year of diabetes diagnosis (1970-79, 1980-89, and 1990-99) were assessed. Patterns of duration-specific incidences were evaluated by fitting generalised additive models to the data, which were split into multiple observations of half-year duration. Cumulative incidences were calculated with Kaplan-Meier analysis. In analyses with kidney failure as the endpoint, competing risk for mortality was incorporated.

FINDINGS

In our stratified random sample, 462 individuals were diagnosed with diabetes in 1970-79, 481 were diagnosed in 1980-89, and 487 were diagnosed in 1990-99. The incidence rate pattern of severe albuminuria changed over time; a peak at 15-19 years since diabetes onset in the 1970-79 cohort was not replicated in those diagnosed later. In the combined 1980-99 diagnosis-year cohorts, the incidence rate rose during the first 14 years after diabetes onset, after which it levelled off to a plateau. Between the 1970-79 and 1980-89 diabetes diagnosis cohorts, the cumulative incidence of severe albuminuria had approximately halved (hazard ratio [HR] 0·55 [95% CI 0·42-0·72] with the 1970-79 cohort as reference, p<0·0001), whereas, between the 1980-89 and 1990-99 cohorts, no further decrease was observed (HR 0·83 [0·54-1·26] with the 1980-89 cohort as reference, p=0·38). The 25-year cumulative incidence for severe albuminuria was 26·8% (22·6-30·8) in the 1970-79 diagnosis cohort, 12·0% (9·0-15·0) in the 1980-89 cohort, and 10·8% (6·7-14·6) in the 1990-99 cohort. 15 years after onset of severe albuminuria, cumulative progression rate from severe albuminuria to kidney failure was 35·2% (27·4-43·0) in the 1970-79 cohort and 35·6% (24·3-47·0) in the 1980-99 cohorts combined (Gray's test p=0·37). In the cohorts with data on moderate albuminuria (1980-89 and 1990-99), cumulative incidence of moderate albuminuria showed no calendar effect between the earlier and later cohorts (HR 0·99 [0·78-1·28] with the 1980-89 cohort as reference, p=0·97). The incidence rate of moderate albuminuria increased until 10 years after diabetes onset, then remained mostly stable until starting to decrease at around 25 years after diabetes onset.

INTERPRETATION

Our analyses show that the cumulative incidence of severe albuminuria has decreased between 1970-79 and 1980-99; however, whether this decrease solely denotes a delay in albuminuria, or also a true prevention of albuminuria, needs to be investigated further. Nevertheless, diabetic kidney disease remains a significant complication of type 1 diabetes. Due to the robust association of diabetic kidney disease with premature mortality, novel therapies to improve prognosis are needed.

FUNDING

Folkhälsan Research Foundation, Medical Society of Finland, Wilhelm and Else Stockmann Foundation, Finnish Diabetes Research Foundation, Waldemar von Frenckell Foundation, Liv och Hälsa Society, Academy of Finland, and Novo Nordisk Foundation.

TRANSLATIONS

For the Finnish and Swedish translations of the abstract see Supplementary Materials section.

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.

Mitochondrial Regulation of Diabetic Kidney Disease

The role and nature of mitochondrial dysfunction in diabetic kidney disease (DKD) has been extensively studied. Yet, the molecular drivers of mitochondrial remodeling in DKD are poorly understood. Diabetic kidney cells exhibit a cascade of mitochondrial dysfunction ranging from changes in mitochondrial morphology to significant alterations in mitochondrial biogenesis, biosynthetic, bioenergetics and production of reactive oxygen species (ROS). How these changes individually or in aggregate contribute to progression of DKD remain to be fully elucidated. Nevertheless, because of the remarkable progress in our basic understanding of the role of mitochondrial biology and its dysfunction in DKD, there is great excitement on future targeted therapies based on improving mitochondrial function in DKD. This review will highlight the latest advances in understanding the nature of mitochondria dysfunction and its role in progression of DKD, and the development of mitochondrial targets that could be potentially used to prevent its progression.

Renal function decline in older men and women with advanced chronic kidney disease-results from the EQUAL study

INTRODUCTION

Understanding the mechanisms underlying the differences in renal decline between men and women may improve sex-specific clinical monitoring and management. To this end, we aimed to compare the slope of renal function decline in older men and women in chronic kidney disease (CKD) Stages 4 and 5, taking into account informative censoring related to the sex-specific risks of mortality and dialysis initiation.

METHODS

The European QUALity Study on treatment in advanced CKD (EQUAL) study is an observational prospective cohort study in Stages 4 and 5 CKD patients ≥65 years not on dialysis. Data on clinical and demographic patient characteristics were collected between April 2012 and December 2018. Estimated glomerular filtration rate (eGFR) was calculated using the CKD Epidemiology Collaboration equation. eGFR trajectory by sex was modelled using linear mixed models, and joint models were applied to deal with informative censoring.

RESULTS

We included 7801 eGFR measurements in 1682 patients over a total of 2911 years of follow-up. Renal function declined by 14.0% [95% confidence interval (CI) 12.9-15.1%] on average each year. Renal function declined faster in men (16.2%/year, 95% CI 15.9-17.1%) compared with women (9.6%/year, 95% CI 6.3-12.1%), which remained largely unchanged after accounting for various mediators and for informative censoring due to mortality and dialysis initiation. Diabetes was identified as an important determinant of renal decline specifically in women.

CONCLUSION

In conclusion, renal function declines faster in men compared with women, which remained similar after adjustment for mediators and despite a higher risk of informative censoring in men. We demonstrate a disproportional negative impact of diabetes specifically in women.

Sexual dimorphism in the progression of type 2 diabetic kidney disease in T2DN rats

Diabetic kidney disease (DKD) is a common complication of diabetes, which frequently leads to end-stage renal failure and increases cardiovascular disease risk. Hyperglycemia promotes renal pathologies such as glomerulosclerosis, tubular hypertrophy, microalbuminuria, and a decline in glomerular filtration rate. Importantly, recent clinical data have demonstrated distinct sexual dimorphism in the pathogenesis of DKD in people with diabetes, which impacts both severity- and age-related risk factors. This study aimed to define sexual dimorphism and renal function in a nonobese type 2 diabetes model with the spontaneous development of advanced diabetic nephropathy (T2DN rats). T2DN rats at 12- and over 48-wk old were used to define disease progression and kidney injury development. We found impaired glucose tolerance and glomerular hyperfiltration in T2DN rats to compare with nondiabetic Wistar control. The T2DN rat displays a significant sexual dimorphism in insulin resistance, plasma cholesterol, renal and glomerular injury, urinary nephrin shedding, and albumin handling. Our results indicate that both male and female T2DN rats developed nonobese type 2 DKD phenotype, where the females had significant protection from the development of severe forms of DKD. Our findings provide further evidence for the T2DN rat strain's effectiveness for studying the multiple facets of DKD.

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

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

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.

Diabetic kidney disease in type 2 diabetes: a review of pathogenic mechanisms, patient-related factors and therapeutic options

The global prevalence of diabetic kidney disease is rapidly accelerating due to an increasing number of people living with type 2 diabetes. It has become a significant global problem, increasing human and financial pressures on already overburdened healthcare systems. Interest in diabetic kidney disease has increased over the last decade and progress has been made in determining the pathogenic mechanisms and patient-related factors involved in the development and pathogenesis of this disease. A greater understanding of these factors will catalyse the development of novel treatments and influence current practice. This review summarises the latest evidence for the factors involved in the development and progression of diabetic kidney disease, which will inform better management strategies targeting such factors to improve therapeutic outcomes in patients living with diabetes.

Renoprotective effects of estrogen on acute kidney injury: the role of SIRT1

Acute kidney injury (AKI) is a common syndrome associated with high morbidity and mortality, despite progress in medical care. Many studies have shown that there are sex differences and different role of sex hormones particularly estrogens in kidney injury. In this regard, the incidence and rate of progression of kidney diseases are higher in men compared with women. These observations suggest that female sex hormone may be renoprotective. Silent information regulator 2 homolog 1 (SIRT1) is a histone deacetylase, which is implicated in multiple biologic processes in several organisms. In the kidneys, SIRT1 inhibits renal cell apoptosis, inflammation, and fibrosis. Studies have reported a link between SIRT1 and estrogen. In addition, SIRT1 regulates ERα expression and inhibition of SIRT1 activity suppresses ERα expression. This effect leads to inhibition of estrogen-responsive gene expression. In this text, we review the role of SIRT1 in mediating the protective effects of estrogen in the onset and progression of AKI.

Diabetes, Hypertension, and Incidence of Chronic Kidney Disease: Is There any Multiplicative or Additive Interaction?

BACKGROUND

The burden of chronic kidney disease (CKD) is on the rise worldwide; diabetes and hypertension are mentioned as the main contributors.

OBJECTIVES

The current study aimed to investigate the multiplicative and additive interaction of diabetes and hypertension in the incidence of CKD.

METHODS

In this population-based cohort study, 7342 subjects aged 20 years or above (46.8% male) were divided into four groups: no diabetes and hypertension; diabetes and no hypertension; hypertension and no diabetes; and both diabetes and hypertension. The multivariable Cox regression was used to determine the effect of diabetes, hypertension, and their multiplicative interaction on CKD. The following indices were used to determine the additive interaction of diabetes and hypertension: the relative excess risk of interaction, the attributable proportion due to interaction, and the synergism index.

RESULTS

Diabetes and hypertension had no significant multiplicative interaction in men (hazard ratio of 0.93, P value: 0.764) and women (hazard ratio of 0.79, P value: 0.198); furthermore, no additive interaction was found in men (relative excess risk due to interaction of 0.79, P value: 0.199; attributable proportion due to interaction of 0.22, P value: 0.130; synergy index of 1.44, P value: 0.183) and women (relative excess risk due to interaction of -0.26, P value: 0.233, attributable proportion due to interaction of -0.21, P value: 0.266; synergy index of 0.48, P value: 0.254).

CONCLUSIONS

This study demonstrated no synergic effect between diabetes and hypertension on the incidence of CKD.

Sex differences in renal mitochondrial function: a hormone-gous opportunity for research

Sex differences (biological distinctions between males and females) present a complex interplay of genetic, developmental, biological, and environmental factors. More and more studies are shedding light on the importance of sex differences in normal physiology and susceptibility to cancer, cardiovascular and renal conditions, and neurodegenerative diseases. This mini-review is devoted to the role of sex dimorphisms in renal function, with a focus on the distinctions between male and female mitochondria. Here, we cover the aspects of renal mitochondrial bioenergetics where sex differences have been reported to date, for instance, biogenesis, reactive oxygen species production, and oxidative stress. Special attention is devoted to the effects of sex hormones, such as estrogen and testosterone, on mitochondrial bioenergetics in the kidney in physiology and pathophysiology.

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.

High sucrose diet induces morphological, structural and functional impairments in the renal tubules of Drosophila melanogaster: A model for studying type-2 diabetes mediated renal tubular dysfunction

Continuous feeding of high dietary sugar is strongly associated with type 2 diabetes (T2D) and its secondary complications. Diabetic nephropathy (DN) is a major secondary complication that leads to glomerular and renal tubular dysfunction. The present study is aimed to investigate the effects of chronic exposure of high sugar diet (HSD) on renal tubules. Malpighian tubules (MTs), a renal organ of Drosophila, were used as a model in the study. Feeding of HSD develops T2D condition in Drosophila. The MTs showed structural abnormalities in 20 days of HSD fed flies. Impaired insulin signaling, oxidative stress, enhanced levels of AGE-RAGE and induction of apoptosis were observed in the MTs of these flies. Further, altered expression of transporters, enhanced uric acid level and reduced fluid secretion rate confirmed the impaired function of MTs in these flies. RNA-seq and RT-PCR analyses in the MTs of HSD fed-and control-flies revealed the altered expression of candidate genes that regulate several important pathways including extracellular matrix (ECM), advanced glycation end products-receptor for advanced glycation end products (AGE-RAGE), transforming growth factor β (TGF-β), galactose, starch and sucrose metabolism that are well known mediators of renal tubular dysfunction in DN patients. Disruption of insulin signaling in the MTs also causes renal tubular dysfunction similar to HSD fed flies. Overall, the study suggests that phenotypes observed in the MTs of HSD fed flies recapitulate several hallmarks of renal tubular dysfunction in DN patients. Therefore, we conclude that MTs of HSD fed flies may be used for deciphering the underlying mechanisms of T2D mediated renal tubular dysfunction.

Level of hormones in menopause in relation to diabetic retinopathy among type 2 diabetic women

Hormonal transition among middle-aged women with type 2 diabetes may exert an impact in the development of diabetic retinopathy (DR). In this cross-sectional study, we aimed to assess the levels of estradiol, follicle-stimulating hormone (FSH), and luteinizing hormone (LH) in the presence of DR and their relationship with risk factors for DR among pre- and post-menopausal women with type 2 diabetes. Serum levels of estradiol, FSH, and LH were measured using the immunoassay technique. All statistical analysis was performed using SPSS software. From the 255 participants, diabetes duration-matched, 35 premenopausal, and 57 postmenopausal women were selected for analysis. The levels of estradiol, LH, and FSH were found to be similar in participants with and without DR among pre- and post-menopausal women with diabetes. Estradiol level was not found to be related with the risk factors of DR among women with type 2 diabetes. In conclusion, female sex hormone, estradiol is not related to the presence of DR. Further prospective studies are necessary to reveal the mechanistic role of this hormone in the development of DR.

Diabetes Mellitus and Gender Have a Negative Impact on the Outcome of Hip Fracture Surgery-A Pilot Study

Diabetes mellitus (DM) is associated with an elevated risk of post-operative complications. The impact it has on patients living with DM following hip fracture surgery (HFS) is not completely understood and may represent a predictor of increased mortality. This study investigates the impact of DM, gender, American Society of Anaesthesiologists (ASA) grade, and fracture location, on the outcome of HFS in Ireland. The Hospital Inpatient Enquiry (HIPE) database records all fragility hip fractures within Galway University Hospital. Retrospective data collection was performed over a 3-year period. Data collected included patient age, gender, date of HFS, anatomical fracture location, type of operation, ASA grade, DM status, and mortality. A database of 650 individuals was created including 461 females and 189 males, with an average group age of 80.2 ± 9.3 years. Results showed a significantly higher incidence of hip fractures in males with DM (19.57%) than females with DM (12.36%) (χ² test, p = 0.020). Cox regression survival analysis indicated that DM status and ASA grade were the two main independent predictors of patient survival following HFS. Nevertheless, when examining the combined impact of gender and DM status on survival after HFS, results showed that survival post HFS differed significantly with gender and presence of DM (log-rank test, p < 0.001), with males with DM performing worse than females with DM (p = 0.021) or males without DM (p = 0.001). This gender and disease-associated outcome should prompt an early multi-disciplinary team approach to the management of hip fractures in patients with DM. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:834-842, 2020.

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.

Sex hormones and their influence on chronic kidney disease

PURPOSE OF REVIEW

The majority of end-stage renal disease including dialysis and kidney transplant patients are men. In contrast, the incidence of chronic kidney disease (CKD) is higher in women compared with men. In this review, we dissect the sex hormone levels and its effects on experimental models and patients with CKD.

RECENT FINDINGS

Sex hormones are clearly involved in CKD progression to end-stage renal disease (ESRD). A significant reduction in lipid peroxidation as a mechanism of renoprotection has been observed in kidneys of streptozotocin (STZ)-diabetic ovariectomized rats after estradiol administration. Furthermore, a G-protein-coupled estrogen receptor inhibits podocyte oxidative stress maintaining the integrity of the mitochondrial membrane. Sex hormone depletion has been shown to modulate RAS system and protect against kidney injury in the male STZ-diabetic model. In human primary proximal tubular epithelial cells, a proteomic study showed that dihydrotestosterone dysregulated metabolic, suggesting that the deleterious effect of androgens within the kidney maybe related to altered energy metabolism in renal tubules.

SUMMARY

Male gender is associated with worse CKD progression and this fact may be ascribed to sex hormone. Although male hormones exert a deleterious effect in terms of increasing oxidative stress, activating RAS system, and worsening fibrosis within the damaged kidney, female hormones exert a renoprotective effect.

Influence of Sex on the Progression of Chronic Kidney Disease

The role that sex plays in the development and progression of chronic kidney disease remains a subject of controversy. The lack of clarity in this important area reflects complex interactions between biological factors and cultural and socioeconomic influences that impact the relationship between sex and renal disease. Certainly, additional observational studies are indicated; however, innovative approaches are required to isolate biological processes from cultural influences. Despite these limitations, available data suggest that the progression of renal disease is slower in women than in men and that this sexual dimorphism is primarily due to direct actions of sex hormones on cellular metabolism. The extent to which differences in lifestyle factors between the sexes influence sexual dimorphism in the progression of chronic kidney disease remains to be elucidated.

Race and sex differences in rates of diabetic complications

BACKGROUND

Studies on racial differences in diabetic complications are very limited. The aim of this study was to investigate the race and sex differences in diabetic complications between African Americans and Whites with type 2 diabetes (T2D) in Louisiana.

METHODS

A prospective cohort study was performed of 27 113 African Americans and 40 431 Whites with T2D who were 35 to 95 years of age from three healthcare systems located in south Louisiana. Four major diabetic complications were assessed: coronary heart disease (CHD), heart failure, stroke, and end-stage renal disease (ESRD).

RESULTS

The age- and sex-adjusted incident rates per 1000 person-years and 95% confidence intervals (CI) for CHD, heart failure, stroke, and ESRD for African Americans with diabetes were 43.1 (95% CI 41.6-44.6), 36.6 (95% CI 35.2-37.9), 29.6 (95% CI 28.4-30.8), and 38.3 (95% CI 36.9-39.7), respectively. Cox regression models showed that African American women had a higher risk than White women for heart failure (hazard ratio (HR) 1.26; 95% CI 1.18-1.34), stroke (HR 1.15; 95% CI 1.08-1.22), and ESRD (HR 1.32; 95% CI 1.24-1.40), whereas African American men had higher risks than White men for heart failure (HR 1.33; 95% CI 1.25-1.43) and ESRD (HR 1.47; 95% CI 1.37-1.57) but a lower risk of CHD (HR 0.88; 95% CI 0.83-0.94).

CONCLUSIONS

The incidence of major diabetic complications varied among difference race and sex groups. More race- or sex-specific studies on complications in patients with diabetes are needed to see whether incident rates are changing over time.

Sex-specific clinical outcomes of impaired glucose status: A long follow-up from the Tehran Lipid and Glucose Study

AIMS

To investigate the sex-specific associations of prediabetes with major clinical outcomes including incident type 2 diabetes, chronic kidney disease, hypertension, coronary heart disease, stroke and all-cause mortality.

METHODS

Among 8498 Iranian adults from the Tehran Lipid and Glucose Study, aged ≥30 years and without diagnosed type 2 diabetes, gender-interactions were assessed for each outcome, followed by sex-separated multivariate-adjusted Cox proportional hazard models to calculate hazard ratios and 95% confidence intervals (CIs) of different prediabetes categories, including impaired fasting glucose (IFG), defined by the American Diabetes Association (ADA) and World Health Organization (WHO), as fasting plasma glucose of 5.6-6.9 mmol/L and 6.1-6.9 mmol/L, respectively, and impaired glucose tolerance, defined as 2-h post challenge plasma glucose of 7.8-11 mmol/L.

RESULTS

Sex-specific associations existed for men between IFG-ADA and chronic kidney disease (hazard ratio: 1.28, 95% CI 0.99-1.65; p_interaction = 0.008) and between IFG-WHO and stroke (hazard ratio: 2.15, 95% CI 1.08-4.27; p_interaction = 0.21); and for women between IFG-ADA and hypertension (hazard ratio: 1.24, 95% CI 1.04-1.48; p_interaction = 0.06) and between impaired glucose tolerance and coronary heart disease (hazard ratio: 1.57, 95% CI 1.14-2.16; p_interaction = 0.05). Among both genders, all prediabetes definitions were associated with type 2 diabetes but none with mortality.

CONCLUSIONS

The hazards of prediabetes definitions may differ between genders depending on the outcome of interest. IFG-WHO among men and impaired glucose tolerance among women are particularly important because of their association with incident stroke and coronary heart disease, respectively. Considering these sex differences could improve personalized management of prediabetes.

Effects of gender, age and treatment duration on lipid profile and renal function indices in diabetic patients attending a teaching hospital in South-Western Nigeria

Background

Type 2 Diabetes Mellitus (T2DM) is associated with diabetic nephropathy and hyperlipidemia. Gender, age, medication adherence, lifestyle, culture and socioeconomic status could be sources of diversity in T2DM leading to differences in predisposition, development and clinical presentation.

Objectives

Therefore, this study aimed to investigate the influence of gender, age and treatment duration on kidney and lipid-related biochemical indices of T2DM patients attending Ekiti State University Teaching Hospital, Ado-Ekiti, Nigeria (EKSUTH).

Methods

Blood from diabetic patients and healthy subjects was analysed for fasting blood glucose (FBG), renal function parameters and lipid profile. Influence of age, gender and treatment duration on indices was assessed using standard baseline values.

Results

Dyslipidemia was pronounced among female diabetics while the incidence of diabetes was found to be higher in middle-age. The percentage of diabetics with high levels of FPG, urea, creatinine, cholesterol, triglyceride and low density lipoprotein-cholesterol after 9–10 years of treatment were lower compared with the percentage after 5–6 years of treatment.

Conclusion

Gender, age and treatment duration influenced clinical course of T2DM among patients presenting at EKSUTH but long term treatment appeared to improve T2DM among patients.

Renoprotective impact of estrogen receptor-α and its splice variants in female mice with type 1 diabetes

Estrogen has been implicated in the regulation of growth and immune function in the kidney, which expresses the full-length estrogen receptor-α (ERα66), its ERα splice variants, and estrogen receptor-β (ERβ). Thus, we hypothesized that these splice variants may inhibit the glomerular enlargement that occurs early in type 1 diabetes (T1D). T1D was induced by streptozotocin (STZ) injection in 8- to 12-wk-old female mice lacking ERα66 (ERα66KO) or all ERα variants (αERKO), and their wild-type (WT) littermates. Basal renal ERα36 protein expression was reduced in the ERα66KO model and was downregulated by T1D in WT mice. T1D did not alter ERα46 or ERβ in WT-STZ; however, ERα46 was decreased modestly in ERα66KO mice. Renal hypertrophy was evident in all diabetic mice. F4/80-positive immunostaining was reduced in ERα66KO compared with WT and αERKO mice but was higher in STZ than in Control mice across all genotypes. Glomerular area was greater in WT and αERKO than in ERα66KO mice, with T1D-induced glomerular enlargement apparent in WT-STZ and αERKO-STZ, but not in ERα66KO-STZ mice. Proteinuria and hyperfiltration were evident in ERα66KO-STZ and αERKO-STZ, but not in WT-STZ mice. These data indicate that ERα splice variants may exert an inhibitory influence on glomerular enlargement and macrophage infiltration during T1D; however, effects of splice variants are masked in the presence of the full-length ERα66, suggesting that ERα66 acts in opposition to its splice variants to influence these parameters. In contrast, hyperfiltration and proteinuria in T1D are attenuated via an ERα66-dependent mechanism that is unaffected by splice variant status.

The Relationship between Renal Function and Bone Marrow Density in Healthy Korean Women

OBJECTIVES

The relationship between renal function and bone mineral density (BMD) is controversial. We evaluated the relationship between markers of renal function and BMD in healthy Korean women.

METHODS

A total of 1,093 women who visited the health promotion center at Pusan National University hospital were included in the cross-sectional study. We divided the study population into two groups by BMD: osteopenia-osteoporosis and normal in the lumbar and femur regions, respectively. We compared the relationship between renal function and BMD using a logistic regression model and used SAS 9.3 (SAS Institute, Inc., Cary, NC, USA) for all statistical analysis.

RESULTS

Blood urea nitrogen (BUN), creatinine, and cystatin C (Cys-C) were correlated with BMD in both the normal and osteopenia-osteoporosis groups, and in logistic regression analysis, BUN and Cys-C were correlated with lumbar and femur BMD. However, after we adjusted for age, menopause, and body mass index, only creatinine showed a negative correlation with lumbar BMD, and estimated glomerular filtration rate (eGFR) was related positively with femur BMD.

CONCLUSIONS

Serum creatinine could be a marker for lumbar BMD and eGFR for femur BMD in Korean women without overt nephropathy.

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.

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.

Longitudinal Changes in Measured Glomerular Filtration Rate, Renal Fibrosis and Biomarkers in a Rat Model of Type 2 Diabetic Nephropathy

BACKGROUND

Obese ZSF-1 rats display many features of human type II diabetes including nephropathy (DN). The study aimed to further understand the relevance of this model to DN, for which glomerular filtration rate (GFR), renal fibrosis and several urinary/tissue biomarkers was followed over 24 weeks in ZSF-1 rats.

METHODS

Intact/sham or uninephrectomized male and female ZSF-1 rats were studied. GFR was measured by transdermal clearance of fluorescein isothiocyanate-sinistrin. Urine was collected every 2-4 weeks for biomarker analysis. Renal tissue was examined histologically for fibrosis and for levels of inflammatory and fibrotic genes.

RESULTS

Male obese ZSF-1 rats demonstrated metabolic syndrome and proteinuria. Female counterparts were hyperlipidemic with delayed proteinuria, but were not hyperglycemic. Kidney hyperfiltration was observed in male obese rats in weeks 2-4 after surgery, and subsequently declined to levels significantly lower than controls. Tubulointerstitial/glomerular fibrosis in male obese rats was significantly elevated by week 12 post surgery and continued to expand in the ensuing weeks, particularly in uninephrectomized rats. Female rats had less severe fibrosis. Except for epidermal growth factor which decreased, the levels of several key inflammatory, injury and fibrotic factors were elevated in both tissue (mRNA) and urine (protein) of male obese rats.

CONCLUSION

Male obese ZSF-1 rats represent an important DN model, manifesting key pathophysiological features including metabolic syndrome, proteinuria, progressive tubular and glomerular fibrosis, and transient hyperfiltration followed by progressive decline in renal function. Uninephrectomy significantly accelerated disease progression. Females were less severe in disease manifestation. Several urinary and tissue biomarkers were identified in the male obese rats that tracked with disease progression.

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

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

ISN Forefronts Symposium 2015: Nuclear Receptors and Diabetic Nephropathy

Diabetic nephropathy (DN) is the major reason for end stage renal disease in the western world. Patients with DN developed more severe cardiovascular complications with worse prognosis. In spite of tight blood pressure and glucose control through applying angiotensin II receptor antagonism, angiotensin receptor inhibitors and even direct renin inhibitors, the progression and development of DN has continued to accelerate. Nuclear receptors are, with few exceptions, ligand-depended transcription factors some of which modulate genes involved in the transportation and metabolism of carbohydrate or lipid, and inflammation. Considering the diverse biological functions of nuclear receptors, efforts have been made to explore their contributions to the pathogenesis of DN and potential therapeutic strategies. This review is mainly focused on the association between various nuclear receptors and the pathogenesis of DN, the potential beneficial effects of targeting these receptors for preventing the progress of DN, and the important role that nuclear receptors may play in future therapeutic strategies for DN.

Sex Differences in the Renal Function Decline of Patients with Type 2 Diabetes

Aims. We aimed to investigate the sex differences in the renal function decline among patients with type 2 diabetic mellitus (T2DM), focusing on the differences in the risk factors at early stage of renal dysfunction. Methods. A clinic-based retrospective longitudinal study (follow-up duration: 8.1 ± 1.4 years) was conducted to assess the sex differences in the annual estimated glomerular filtration rate (eGFR) change in 344 (247 male and 97 female) Japanese T2DM patients. The sex differences in the risk factors of annual eGFR decline were subjected to linear regression analyses. Results. The mean annual eGFR change was -3.5 ± 2.7%/year in females and -2.0 ± 2.2%/year in males (P < 0.001). Baseline retinopathy and proteinuria were significantly associated with a larger eGFR decline, irrespective of sex, while HbA1c and LDL-cholesterol levels were significantly associated with an eGFR decline in females only. Interactive effects were observed between sex and the HbA1c, LDL-cholesterol, retinopathy, or proteinuria levels on the annual eGFR decline. Conclusions. The increased susceptibility to poor metabolic control seemed to contribute to a higher risk of renal dysfunction in females with T2DM. Our study highlights the importance of aggressive therapeutic intervention to improve metabolic profiles at early stage, especially in females.

RAS and sex differences in diabetic nephropathy

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

C-Reactive protein and insulin growth factor 1 serum levels during the menstrual cycle in adolescents with Type 1 diabetes

AIMS

To evaluate C-reactive protein, insulin growth factor 1 and lipid levels during the follicular and luteal phases in adolescents with Type 1 diabetes.

METHODS

Adolescents with Type 1 diabetes (N = 40) and healthy controls (C; N = 43) were studied during the follicular and luteal phases of their menstrual cycles. C-Reactive protein, insulin growth factor 1 and lipid levels were measured.

RESULTS

Adolescents with Type 1 diabetes exhibited higher C-reactive protein levels than the C group during the follicular (P < 0.0001) and luteal phases (P < 0.01). The elevation of C-reactive protein levels was more pronounced in overweight adolescents with Type 1 diabetes than in adolescents in the C group. More adolescents with Type 1 diabetes were classified as having an elevated risk of cardiovascular disease (C-reactive protein > 3 mg/l) in the luteal phase than in the follicular phase (37.5% and 17.5%, respectively); half of the overweight adolescents with Type 1 diabetes in the luteal phase reached this level. BMI was the only significant factor affecting follicular and luteal phase C-reactive protein levels in adolescents with Type 1 diabetes. Lower insulin growth factor 1 levels were observed during both phases of the menstrual cycle in adolescents with Type 1 diabetes compared with controls. An elevation in insulin growth factor 1 levels in the luteal phase relative to the follicular phase was observed in controls, but not in adolescents with Type 1 diabetes. Luteal insulin growth factor 1 and C-reactive protein exhibited an inverse correlation (r = -0.4, P = 0.01).

CONCLUSIONS

Adolescents with Type 1 diabetes have higher C-reactive protein levels and lower insulin growth factor 1 levels relative to controls, especially during the luteal phase. Type 1 diabetes diminishes the natural elevation in insulin growth factor 1 levels observed during the luteal phase in controls. Excess weight exacerbates the subclinical inflammatory state observed during both phases of the menstrual cycle in adolescents with Type 1 diabetes.

Microvascular Complications and Their Associated Risk Factors in Newly Diagnosed Type 2 Diabetes Mellitus Patients

The study was aimed at assessing the prevalence of microvascular complications and associated risk factors in newly diagnosed type 2 diabetes mellitus patients. A cross-sectional study was conducted in a public tertiary care hospital. All the recruited patients underwent extensive examination for the presence of microvascular complications like neuropathy, retinopathy, and nephropathy. Prevalence of any complication was 18.04%. Prevalence of neuropathy, retinopathy, and nephropathy was found to be 8.2%, 9.5%, and 2.8%, respectively. Triglycerides (OR, 1.01; P = 0.011) and old age (OR, 1.06; P ≤ 0.01) were significantly associated with any complication. Triglycerides were significantly associated with neuropathy (OR, 1.01; P = 0.05) and retinopathy (OR, 1.01; P = 0.02). Being male posed high risk for nephropathy (OR, 0.06; P = 0.01). These results are suggesting need of regular screening for microvascular complications.

Diabetic nephropathy and its risk factors in a society with a type 2 diabetes epidemic: a Saudi National Diabetes Registry-based study

Aims

The prevalence of diabetic nephropathy and its risk factors have not been studied in a society known to have diabetes epidemic like Saudi Arabia. Using a large data base registry will provide a better understanding and accurate assessment of this chronic complication and its related risk factors.

Methodology

A total of 54,670 patients with type 2 diabetes aged ≥25 years were selected from the Saudi National Diabetes Registry (SNDR) and analyzed for the presence of diabetic nephropathy. The American Diabetes Association (ADA) criterion was used to identify cases with microalbuminuria, macroalbuminuria and end stage renal disease (ESRD) for prevalence estimation and risk factor assessment.

Results

The overall prevalence of diabetic nephropathy was 10.8%, divided into 1.2% microalbuminuria, 8.1%macroalbuninuria and 1.5% ESRD. Age and diabetes duration as important risk factors have a strong impact on the prevalence of diabetic nephropathy, ranging from 3.7% in patients aged 25–44 years and a duration of >5 years, to 21.8% in patients ≥65 years with a diabetes duration of ≥15 years. Diabetes duration, retinopathy, neuropathy, hypertension, age >45 years, hyperlipidemia, male gender, smoking, and chronologically, poor glycemic control has a significantly high risk for diabetic nephropathy.

Conclusion

The prevalence of diabetic nephropathy is underestimated as a result of a shortage of screening programs. Risk factors related to diabetic nephropathy in this society are similar to other societies. There is thus an urgent need for screening and prevention programs for diabetic nephropathy among the Saudi population.

Pathophysiology of the diabetic kidney

Diabetes mellitus contributes greatly to morbidity, mortality, and overall health care costs. In major part, these outcomes derive from the high incidence of progressive kidney dysfunction in patients with diabetes making diabetic nephropathy a leading cause of end-stage renal disease. A better understanding of the molecular mechanism involved and of the early dysfunctions observed in the diabetic kidney may permit the development of new strategies to prevent diabetic nephropathy. Here we review the pathophysiological changes that occur in the kidney in response to hyperglycemia, including the cellular responses to high glucose and the responses in vascular, glomerular, podocyte, and tubular function. The molecular basis, characteristics, and consequences of the unique growth phenotypes observed in the diabetic kidney, including glomerular structures and tubular segments, are outlined. We delineate mechanisms of early diabetic glomerular hyperfiltration including primary vascular events as well as the primary role of tubular growth, hyperreabsorption, and tubuloglomerular communication as part of a "tubulocentric" concept of early diabetic kidney function. The latter also explains the "salt paradox" of the early diabetic kidney, that is, a unique and inverse relationship between glomerular filtration rate and dietary salt intake. The mechanisms and consequences of the intrarenal activation of the renin-angiotensin system and of diabetes-induced tubular glycogen accumulation are discussed. Moreover, we aim to link the changes that occur early in the diabetic kidney including the growth phenotype, oxidative stress, hypoxia, and formation of advanced glycation end products to mechanisms involved in progressive kidney disease.

Chromosome 2q31.1 associates with ESRD in women with type 1 diabetes

Sex and genetic variation influence the risk of developing diabetic nephropathy and ESRD in patients with type 1 diabetes. We performed a genome-wide association study in a cohort of 3652 patients from the Finnish Diabetic Nephropathy (FinnDiane) Study with type 1 diabetes to determine whether sex-specific genetic risk factors for ESRD exist. A common variant, rs4972593 on chromosome 2q31.1, was associated with ESRD in women (P<5×10(-8)) but not in men (P=0.77). This association was replicated in the meta-analysis of three independent type 1 diabetes cohorts (P=0.02) and remained significant for women (P<5×10(-8); odds ratio, 1.81 [95% confidence interval, 1.47 to 2.24]) upon combined meta-analysis of the discovery and replication cohorts. rs4972593 is located between the genes that code for the Sp3 transcription factor, which interacts directly with estrogen receptor α and regulates the expression of genes linked to glomerular function and the pathogenesis of nephropathy, and the CDCA7 transcription factor, which regulates cell proliferation. Further examination revealed potential transcription factor-binding sites within rs4972593 and predicted eight estrogen-responsive elements within 5 kb of this locus. Moreover, we found sex-specific differences in the glomerular expression levels of SP3 (P=0.004). Overall, these results suggest that rs4972593 is a sex-specific genetic variant associated with ESRD in patients with type 1 diabetes and may underlie the sex-specific protection against ESRD.

Gender and the prevalence and progression of renal disease

In most experimental models of CKD, male animals progress more rapidly than females. Modulation of the hormonal milieu can replicate the effects of gender on the course of kidney disease. These observations suggest that sex hormones per se may be important determinants of the greater susceptibility of males to progressive kidney injury. The predominance of data in humans suggests that the course of nondiabetic kidney disease is more aggressive in men than women. Male gender is arguably also a risk factor for progression of diabetic nephropathy. Sex hormones directly or indirectly affect many cellular processes by modulating the synthesis of various cytokines, growth factors, and vasoactive agents. In particular, estrogen acts in a receptor-dependent mechanism to regulate genes involved in extracellular matrix metabolism. Estrogen has profound effects on transforming growth factor-β signal transduction and on the renin-angiotensin system. These effects may contribute to alterations in kidney hemodynamics and affect kidney disease progression. Selective estrogen receptor modulators, agents that mimic many of the beneficial effects of estrogen without reproducing estrogen's deleterious effects on reproductive tissue, ameliorate the course of kidney disease in animal models and in postmenopausal women.

Sex-specific-differences in cardiometabolic risk in type 1 diabetes: a cross-sectional study

Background

Little is known about the impact of sex-specific differences in the management of type 1 diabetes (T1DM).

Thus, we evaluated the influence of gender on risk factors, complications, clinical care and adherence in patients with T1DM.

Methods

In a cross-sectional study, sex-specific disparities in glycaemic control, cardiovascular risk factors, diabetic complications, concomitant medication use and adherence to treatment recommendations were evaluated in 225 consecutive patients (45.3% women) who were comparable with respect to age, diabetes duration, and body mass index.

Results

Although women with T1DM had a higher total cholesterol than men, triglycerides were higher in obese men and males with HbA1c>7% than in their female counterparts. No sex differences were observed in glycaemic control and in micro- or macrovascular complications. However, the subgroup analysis showed that nephropathy was more common in obese men, hyperlipidaemic women and all hypertensive patients, whereas peripheral neuropathy was more common in hyperlipidaemic women. Retinopathy was found more frequently in women with HbA1c>7%, obese men and in both sexes with a long duration of diabetes. The multivariate analysis revealed that microvascular complications were associated with the duration of disease and BMI in both sexes and with hyperlipidaemia in males. The overall adherence to interventions according to the guidelines was higher in men than in women. This adherence was concerned particularly with co-medication in patients diagnosed with hypertension, aspirin prescription in elderly patients and the achievement of target lipid levels following the prescription of statins.

Conclusions

Our data showed sex differences in lipids and overweight in patients with T1DM. Although glycaemic control and the frequency of diabetic complications were comparable between the sexes, the overall adherence to guidelines, particularly with respect to the prescription of statins and aspirin, was lower in women than in men.