Gender and human chronic renal disease

Early-life exposures and long-term health: adverse gestational environments and the programming of offspring renal and vascular disease

According to the Developmental Origins of Health and Disease hypothesis, exposure to certain environmental influences during early life may be a key determinant of fetal development and short- and long-term offspring health. Indeed, adverse conditions encountered during the fetal, perinatal, and early childhood stages can alter normal development and growth, as well as put the offspring at elevated risk of developing long-term health conditions in adulthood, including chronic kidney disease and cardiovascular diseases. Of relevance in understanding the mechanistic basis of these long-term health conditions are previous findings showing low glomerular number in human intrauterine growth restriction and low birth weight-indicators of a suboptimal intrauterine environment. In different animal models, the main suboptimal intrauterine conditions studied relate to maternal dietary manipulations, poor micronutrient intake, prenatal ethanol exposure, maternal diabetes, glucocorticoid and chemical exposure, hypoxia, and placental insufficiency. These studies have demonstrated changes in kidney structure, glomerular endowment, and expression of key genes and signaling pathways controlling endocrine, excretion, and filtration function of the offspring. This review aims to summarize those studies to uncover the effects and mechanisms by which adverse gestational environments impact offspring renal and vascular health in adulthood. This is important for identifying agents and interventions that can prevent and mitigate the long-term consequences of an adverse intrauterine environment on the subsequent generation.NEW & NOTEWORTHY Human data and experimental animal data show that suboptimal environments during fetal development increase the risk of renal and vascular diseases in adult-life. This is related to permanent changes in kidney structure, function, and expression of genes and signaling pathways controlling filtration, excretion, and endocrine function. Uncovering the mechanisms by which offspring renal development and function is impacted is important for identifying ways to mitigate the development of diseases that strain health care services worldwide.

State of the Science and Ethical Considerations for Preimplantation Genetic Testing for Monogenic Cystic Kidney Diseases and Ciliopathies

There is a broad phenotypic spectrum of monogenic polycystic kidney diseases (PKDs). These disorders often involve cilia-related genes and lead to the development of fluid-filled cysts and eventual kidney function decline and failure. Preimplantation genetic testing for monogenic (PGT-M) disorders has moved into the clinical realm. It allows prospective parents to avoid passing on heritable diseases to their children, including monogenic PKD. The PGT-M process involves embryo generation through in vitro fertilization, with subsequent testing of embryos and selective transfer of those that do not harbor the specific disease-causing variant(s). There is a growing body of literature supporting the success of PGT-M for autosomal-dominant and autosomal-recessive PKD, although with important technical limitations in some cases. This technology can be applied to many other types of monogenic PKD and ciliopathies despite the lack of existing reports in the literature. PGT-M for monogenic PKD, like other forms of assisted reproductive technology, raises important ethical questions. When considering PGT-M for kidney diseases, as well as the potential to avoid disease in future generations, there are regulatory and ethical considerations. These include limited government regulation and unstandardized consent processes, potential technical errors, high cost and equity concerns, risks associated with pregnancy for mothers with kidney disease, and the impact on all involved in the process, including the children who were made possible with this technology.

Renal outcomes in pediatric patients with sickle cell disease: a single center experience in Saudi Arabia

Background

Sickle cell nephropathy (SCN) is a significant complication of sickle cell disease (SCD) with an asymptomatic onset in childhood and potential progression to chronic kidney disease (CKD). The clinical findings of SCN include hyposthenuria, hematuria, proteinuria, hyperfiltration, and CKD. Data on renal manifestation among patients with SCD in Saudi Arabia is lacking. Therefore, this study aimed to evaluate renal outcomes in patients with SCD who visited a hematology clinic at the National Guard Hospital, Jeddah.

Methods

We conducted a retrospective chart review of renal complications in patients with SCD who are within 0-14 years of age and on regular follow-ups at the pediatric hematology clinic in King Abdulaziz Medical City-Jeddah, Saudi Arabia.

Results

Among the 140 patients with SCD, 99 met the inclusion criteria. The median age at diagnosis was 18 (1-108) months. Two SCD phenotypes were observed, with 82 (83%) patients having sickle cell anemia (HbSS) and 17 (17%) having HbS/B+ thalassemia. Of the total patients, 92 (93%) were administered hydroxyurea (HU), with a median starting age of 48 (9-168) months. The most common renal complication observed during routine urinalysis was hematuria (38%), followed by proteinuria (11%). After stratifying the sample into four age groups (0-3 years old, 4-7 years old, 8-11 years old, and 12-14 years old), the mean glomerular filtration rate (GFR) values were 96.16, 101.36, 112.69, and 120.11 ml/min/1.73 m2 respectively. Renal imaging revealed abnormal findings in 27 (29%) patients. The most common abnormality observed on US was increased echogenicity (43%).

Conclusion

SCN is a significant complication of SCD. In this study, we assessed the renal outcomes in pediatric patients with SCD. After analyzing the clinical findings of SCN, we concluded that the presence of renal complications in pediatric patients presented a progressive pattern.

Female sex protects against renal edema, but not lung edema, in mice with partial deletion of the endothelial barrier regulator Tie2 compared to male sex

BACKGROUND

The endothelial angiopoietin/Tie2 system is an important regulator of endothelial permeability and targeting Tie2 reduces hemorrhagic shock-induced organ edema in males. However, sexual dimorphism of the endothelium has not been taken into account. This study investigated whether there are sex-related differences in the endothelial angiopoietin/Tie2 system and edema formation.

METHODS

Adult male and female heterozygous Tie2 knockout mice (Tie2+/-) and wild-type controls (Tie2+/+) were included (n = 9 per group). Renal and pulmonary injury were determined by wet/dry weight ratio and H&E staining of tissue sections. Protein levels were studied in plasma by ELISA and pulmonary and renal mRNA expression levels by RT-qPCR.

RESULTS

In Tie2+/+ mice, females had higher circulating angiopoietin-2 (138%, p<0.05) compared to males. Gene expression of angiopoietin-1 (204%, p<0.01), angiopoietin-2 (542%, p<0.001) were higher in females compared to males in kidneys, but not in lungs. Gene expression of Tie2, Tie1 and VE-PTP were similar between males and females in both organs. Renal and pulmonary wet/dry weight ratio did not differ between Tie2+/+ females and males. Tie2+/+ females had lower circulating NGAL (41%, p<0.01) compared to males, whereas renal NGAL and KIM1 gene expression was unaffected. Interestingly, male Tie2+/- mice had 28% higher renal wet/dry weight ratio (p<0.05) compared to Tie2+/+ males, which was not observed in females nor in lungs. Partial deletion of Tie2 did not affect circulating angiopoietin-1 or angiopoietin-2, but soluble Tie2 was 44% and 53% lower in males and females, respectively, compared to Tie2+/+ mice of the same sex. Renal and pulmonary gene expression of angiopoietin-1, angiopoietin-2, estrogen receptors and other endothelial barrier regulators was comparable between Tie2+/- and Tie2+/+ mice in both sexes.

CONCLUSION

Female sex seems to protect against renal, but not pulmonary edema in heterozygous Tie2 knock-out mice. This could not be explained by sex dimorphism in the endothelial angiopoietin/Tie2 system.

Prevalence of undiagnosed stage 3 chronic kidney disease in France, Germany, Italy, Japan and the USA: results from the multinational observational REVEAL-CKD study

OBJECTIVES

REVEAL-CKD aims to estimate the prevalence of, and factors associated with, undiagnosed stage 3 chronic kidney disease (CKD).

DESIGN

Multinational, observational study.

SETTING

Data from six country-specific electronic medical records and/or insurance claims databases from five countries (France, Germany, Italy, Japan and the USA [two databases]).

PARTICIPANTS

Eligible participants (≥18 years old) had ≥2 consecutive estimated glomerular filtration rate (eGFR) measurements (calculated from serum creatinine values, sex and age) taken from 2015 onwards that were indicative of stage 3 CKD (≥30 and <60 mL/min/1.73 m²). Undiagnosed cases lacked an International Classification of Diseases 9/10 diagnosis code for CKD (any stage) any time before, and up to 6 months after, the second qualifying eGFR measurement (study index).

MAIN OUTCOME MEASURES

The primary outcome was point prevalence of undiagnosed stage 3 CKD. Time to diagnosis was assessed using the Kaplan-Meier approach. Factors associated with lacking a CKD diagnosis and risk of diagnostic delay were assessed using logistic regression adjusted for baseline covariates.

RESULTS

The prevalence of undiagnosed stage 3 CKD was 95.5% (19 120/20 012 patients) in France, 84.3% (22 557/26 767) in Germany, 77.0% (50 547/65 676) in Italy, 92.1% (83 693/90 902) in Japan, 61.6% (13 845/22 470) in the US Explorys Linked Claims and Electronic Medical Records Data database and 64.3% (161 254/250 879) in the US TriNetX database. The prevalence of undiagnosed CKD increased with age. Factors associated with undiagnosed CKD were female sex (vs male, range of odds ratios across countries: 1.29-1.77), stage 3a CKD (vs 3b, 1.81-3.66), no medical history (vs a history) of diabetes (1.26-2.77) or hypertension (1.35-1.78).

CONCLUSIONS

There are substantial opportunities to improve stage 3 CKD diagnosis, particularly in female patients and older patients. The low diagnosis rates in patients with comorbidities that put them at risk of disease progression and complications require attention.

TRIAL REGISTRATION

NCT04847531.

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.

Sex-based analysis of treatment responses in animal models of sepsis: a preclinical systematic review protocol

BACKGROUND

The importance of investigating sex- and gender-dependent differences has been recently emphasized by major funding agencies. Notably, the influence of biological sex on clinical outcomes in sepsis is unclear, and observational studies suffer from the effect of confounding factors. The controlled experimental environment afforded by preclinical studies allows for clarification and mechanistic evaluation of sex-dependent differences. We propose a systematic review to assess the impact of biological sex on baseline responses to disease induction as well as treatment responses in animal models of sepsis. Given the lack of guidance surrounding sex-based analyses in preclinical systematic reviews, careful consideration of various factors is needed to understand how best to conduct analyses and communicate findings.

METHODS

MEDLINE and Embase will be searched (2011-present) to identify preclinical studies of sepsis in which any intervention was administered and sex-stratified data reported. The primary outcome will be mortality. Secondary outcomes will include organ dysfunction, bacterial load, and IL-6 levels. Study selection will be conducted independently and in duplicate by two reviewers. Data extraction will be conducted by one reviewer and audited by a second independent reviewer. Data extracted from included studies will be pooled, and meta-analysis will be conducted using random effects modeling. Primary analyses will be stratified by animal age and will assess the impact of sex at the following time points: pre-intervention, in response to treatment, and post-intervention. Risk of bias will be assessed using the SYRCLE's risk-of-bias tool. Illustrative examples of potential methods to analyze sex-based differences are provided in this protocol.

DISCUSSION

Our systematic review will summarize the current state of knowledge on sex-dependent differences in sepsis. This will identify current knowledge gaps that future studies can address. Finally, this review will provide a framework for sex-based analysis in future preclinical systematic reviews.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42022367726.

The Association between Iron Deficiency and Renal Outcomes Is Modified by Sex and Anemia in Patients with Chronic Kidney Disease Stage 1–4

Iron deficiency is prevalent in women and patients with chronic kidney disease (CKD). Iron deficiency is not only related to anemia but contributes to adverse consequences for the kidney as well. Whether iron status is associated with renal outcomes after considering sex and anemia in patients with CKD stage 1–4 is unclear. Thus, we investigated the association of iron or iron saturation with renal outcomes in a CKD cohort. During a follow-up of 8.2 years, 781 (31.2%) patients met the composite renal outcome of renal replacement therapy and a 50% decline in renal function. In linear regression, iron was associated with sex, hemoglobin (Hb), and nutritional markers. In a fully adjusted Cox regression model, the male patients with normal iron had a significantly decreased risk of renal outcomes (hazard ratio (HR) 0.718; 95% confidence interval (CI) 0.579 to 0.889), but the female patients did not exhibit this association. The non-anemic patients (Hb ≥ 11 g/dL) had a decreased risk of renal outcomes (HR 0.715; 95% CI 0.568 to 0.898), but the anemic patients did not. In the sensitivity analysis, transferrin saturation (TSAT) showed similar results. When comparing iron and TSAT, both indicators showed similar prognostic values. In conclusion, iron deficiency, indicated by either iron or iron saturation, was associated with poor renal outcomes in the male or non-anemic patients with CKD stage 1–4.

Sex-Associated Differences in Short-Term Outcomes in Patients with Deep Sternal Wound Infection after Open-Heart Surgery

Deep sternal wound infection (DSWI) is a feared complication after cardiac surgery. The impact of sex-related differences on wound infection prevalence is poorly understood. Our aim was to evaluate the effect of sex on short-term outcomes in patients with DSWI after open-heart surgery. The study was a retrospective cohort study. A total of 217 patients with DSWI were identified and retrospectively analyzed using our institutional database. Patients were divided into two groups: males (n = 150) and females (n = 67). This study also includes a propensity score based matching (PSM) analysis (male group (n = 62) and female group (n = 62)) to examine the unequal groups. Mean age (p = 0.088) and mean body mass index (BMI) (p = 0.905) did not significantly differ between both groups. Vacuum assisted closure (VAC) therapy was performed among most patients (82.3% (male group) vs. 83.9% (female group), p = 0.432). The most commonly isolated bacteria from the wounds were Staphylococcus epidermidis and Staphylococcus aureus in both groups. Acute renal failure was significantly higher (p = 0.010) in the male group compared to the female group. However, dialysis rate did not significantly differ (p = 0.491) between male and female groups. Further secondary outcomes showed no major differences between the groups. Likewise, in-hospital mortality rate did not differ significantly (p = 0.680) between both groups. Based on our data, sex has no impact on deep wound infection prevalence after cardiac surgery.

Relations of postural change in blood pressure with hypertension-mediated organ damage in middle-aged adults of the Framingham heart study: A cross-sectional study

Background

Dysregulation of compensatory mechanisms to regulate blood pressure (BP) upon postural change is a phenotype of BP variability and an emerging risk factor for cardiovascular outcomes.

Materials and methods

We assessed postural change in BP (starting 2 min after standing from a supine position), carotid-femoral pulse wave velocity (cfPWV), and markers of hypertension-mediated organ damage (HMOD) in the heart, kidney, and brain in Framingham Third Generation, Omni-2, and New Offspring Spouse Cohort participants. We related vascular measures (postural change in BP measures and cfPWV) with HMOD in 3,495 participants (mean age 47 years, 53% women) using multivariable logistic and linear regression models.

Results

In multivariable-adjusted models, we did not observe significant associations of vascular measures with presence of left ventricular hypertrophy, albuminuria, covert brain infarcts, or white matter hyperintensities (Bonferroni-adjusted P-values > 0.05/20 > 0.0025). In multivariable models, greater cfPWV (est. β = 0.11 ± 0.03; P < 0.001), but not postural change in BP measures (Bonferroni-adjusted P-values > 0.05/20 > 0.0025), was associated with higher white matter free water using brain magnetic resonance imaging. In multivariable models, greater postural change in pulse pressure was associated with higher urinary albumin-creatinine ratio (est. β = 0.07 ± 0.02; P < 0.001). No other postural change in BP measure was associated with urinary albumin-creatinine ratio (Bonferroni-adjusted P-values > 0.05/20 > 0.0025). In sex-specific analyses, higher cfPWV was associated with higher urinary albumin-creatinine ratio in men (est. β: 0.11 ± 0.04; P = 0.002) but not in women (est. β: 0.03 ± 0.03; P = 0.44). We also observed marginal to strong effect modification by above vs. at/below median postural change in BP for the association of cfPWV with urinary albumin-creatinine ratio (Bonferroni-adjusted interaction P < 0.001-0.01). Vascular measures were not related to left ventricular mass index or fractional anisotropy (Bonferroni-adjusted P-values > 0.05/20 > 0.0025).

Conclusion

Baroreflex dysfunction is associated with greater subclinical kidney damage. Additionally, relations of higher aortic stiffness with greater kidney damage may be modified by associated baroreflex dysregulation.

Incidence and Predictors of Chronic Kidney Disease among Diabetes Mellitus Patients: A Retrospective Follow-Up Study at a Tertiary Health-Care Setting of Ethiopia

BACKGROUND

Chronic kidney disease (CKD) is one of the most common microvascular complications of diabetes mellitus (DM) and it is a major health burden worldwide. Despite the increasing trend of microvascular complications in developing countries, there is limited evidence on predictors of CKD among diabetic patients in Ethiopia. Therefore, this study was aimed to assess the incidence and predictors of CKD among DM patients.

METHODS

A retrospective follow-up study was conducted among type 1 and type 2 DM patients in Southwest Ethiopia. A total of 437 newly-diagnosed diabetes patients were selected using a simple random sampling technique. Data were extracted from patients' medical records. Cox proportional hazard model was fitted and a 95% confidence interval was used to select significant variables.

RESULTS

Overall, 15.56% of patients developed CKD, with an incidence rate of 2.29 per 1,000 person-month (PM) (95% CI=1.79-2.93). Female sex (AHR=0.51, 95% CI=0.27-0.94) was found to be a protective factor of CKD, while positive proteinuria (AHR=2.85, 95% CI=1.48-5.55), having hypertension (HTN) (AHR=2.31, 95% CI=1.03-5.56), and high-density lipoprotein cholesterol (HDL-C) <40 mg/dL (AHR=3.19, 95% CI=1.73-5.98) were significant predictors of CKD.

CONCLUSION

CKD among DM patients continues to be a significant public health problem in health-care settings of Ethiopia. The current study found being female was protective, while positive proteinuria, HTN, and HDL-C <40 mg/dL were risk factors for CKD. We recommend health professionals to give more attention to DM patients with the identified risk factors.

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.

Endogenous estrogen exposure and chronic kidney disease; a 15-year prospective cohort study

BACKGROUND

Despite strong evidence demonstrating the role of estrogen as a protective factor for kidney function in women, limited data are available regarding the influence of endogenous estrogen exposure (EEE) on chronic kidney disease (CKD). The present study aimed to assess the incidence of CKD in women with various levels of EEE.

METHODS

In a prospective population-based study over a 15-year follow-up, a total of 3043 eligible women aged 30-70 years, participating in Tehran-Lipid and Glucose-Study were recruited and divided into two groups (EEE < 11 and EEE ≥ 11 years). EEE calculated based on age at menarche, age at menopause, number and duration of pregnancies, lactation, and duration of oral contraceptive use after excluding the progesterone dominant phase of the menstrual cycle. Cox's proportional hazards model was applied to estimate the hazard ratio of CKD between the study groups, after adjusting for confounders.

RESULTS

The total cumulative incidence rate of CKD was 50.1 per 1000 person years; 95% CI: 47.7-52.6); this was 53.9 (95%CI, 50.2-57.8) and 47.1 (95%CI, 44.0-50.4) per 1000 person years in women with EEE < 11 and EEE ≥ 11 years, respectively. The model adjusted for age, BMI, smoking, hypertension, and diabetes showed that the hazard ratio (HR) of incidence CKD in women with EEE < 11 compare to those with EEE ≥ 11 years in the subgroup of women aged< 45 years was 2.66(95% CI, 2.2, 3.2), whereas, in the subgroup aged ≥45 years, it was 1.22 (95% CI, 1.04, 1.4).

CONCLUSION

This study shows a higher HR of CKD incidence in women with low EEE levels in their later life. Screening of these women for CKD may be recommended.

The Effects of Biological Sex on Sepsis Treatments in Animal Models: A Systematic Review and a Narrative Elaboration on Sex- and Gender-Dependent Differences in Sepsis

Preclinical studies provide an opportunity to evaluate the relationship between sex and sepsis, and investigate underlying mechanisms in a controlled experimental environment. The objective of our systematic review was to assess the impact of biological sex on treatment response to fluid and antibiotic therapy in animal models of sepsis. Furthermore, we provide a narrative elaboration of sex-dependent differences in preclinical models of sepsis.

DATA SOURCES

MEDLINE and Embase were searched from inception to March 16, 2020.

STUDY SELECTION

All studies reporting sex-stratified data comparing antibiotics and/or fluid resuscitation with a placebo or no treatment arm in an in vivo model of sepsis were included.

DATA EXTRACTION

Outcomes of interest were mortality (primary) and organ dysfunction (secondary). Risk of bias was assessed. Study selection and data extraction were conducted independently and in duplicate.

DATA SYNTHESIS

The systematic search returned 2,649 unique studies, and two met inclusion criteria. Both studies used cecal ligation and puncture models with imipenem/cilastatin antibiotics. No eligible studies investigated fluids. In one study, antibiotic therapy significantly reduced mortality in male, but not female, animals. The other study reported no sex differences in organ dysfunction. Both studies were deemed to be at a high overall risk of bias.

CONCLUSIONS

There is a remarkable and concerning paucity of data investigating sex-dependent differences in fluid and antibiotic therapy for the treatment of sepsis in animal models. This may reflect poor awareness of the importance of investigating sex-dependent differences. Our discussion therefore expands on general concepts of sex and gender in biomedical research and sex-dependent differences in key areas of sepsis research such as the cardiovascular system, immunometabolism, the microbiome, and epigenetics. Finally, we discuss current clinical knowledge, the potential for reverse translation, and directions for future studies.

REGISTRATION

PROSPERO CRD42020192738.

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

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

Tamoxifen attenuates renal fibrosis in human kidney slices and rats subjected to unilateral ureteral obstruction

BACKGROUND AND PURPOSE

Renal fibrosis plays an important role in the development and progression of chronic kidney disease (CKD). Clinical studies have shown that CKD progresses differently in males and females, which may be related to circulating levels of sex hormones. In this study, we investigated the effect of tamoxifen (TAM), a selective estrogen receptor modulator (SERM), on renal fibrosis in male and female rats subjected to unilateral ureteral obstruction (UUO) and human precision-cut kidney slices (PCKS).

EXPERIMENTAL APPROACH

Female, ovariectomized female (OVX), and male rats were subjected to 7 days of UUO and treated with TAM by oral gavage. Moreover, we studied individual responses to TAM treatment in PCKS prepared from female and male patients. In all models, the expression of fibrosis markers was examined by western blot, qPCR, and immunohistochemistry.

KEY RESULTS

TAM decreased the expression of fibronectin, α-smooth muscle actin, and collagen-1 and -3 in female, OVX, and male rats. In addition, TAM mitigated TGF-β-induced fibrosis in human PCKS, irrespective of sex, yet interindividual differences in treatment response were observed.

CONCLUSION AND IMPLICATIONS

TAM ameliorates renal fibrosis in males and females, although we did observe sex differences in drug response. These findings warrant further research into the clinical applicability of TAM, or other SERMs, for the personalized treatment of renal disease.

Cross-sectional study of diabetes kidney disease in the Eastern Cape, South Africa

Diabetes mellitus (DM) is an independent risk factor for the development of kidney disease. This study assesses the prevalence and determinants of asymptomatic kidney disease in individuals with DM attending health facilities in OR Tambo district, Eastern Cape, South Africa.In this cross-sectional analysis, medical data of 327 individuals receiving care for DM in primary health care centers in OR Tambo district, Eastern Cape between June and November 2013 were reviewed. Significant kidney disease was defined as estimated glomerular filtration rate less than 60 mL/min/1.73 m in accordance with the guidelines of the Society of Endocrinology, Metabolism and Diabetes of South Africa (2017).One-quarter of the 327 participants (n = 80) had significant kidney disease. Female sex [odds ratio (OR) = 5.2; 95% confidence interval (95% CI) 1.2-23.5], never used alcohol (OR = 13.4; 95% CI 2.5-72.1), hypertension (OR = 16.2; 95% CI 2.0-130.0), triglyceride (TG)/high-density lipoprotein (HDL) ratio (OR = 1.2; 95% CI 1.0-1.5), current smoker (OR = 1127.9; 95% CI 162.9-7808.9), former smoker (OR = 13.3; 95% CI 4.1-41.4), and longer duration of diabetes (OR = 4.6; 95% CI 1.6-13.0) were the independent determinants of significant kidney disease among the participants. A significant dose--effect relationship exists between renal disease and smoking status (P < .0001), duration of DM (P < .001), glycemic status (P = .025), and body mass index (P = .003).There is a high rate of undiagnosed kidney disease in this setting, which was independently associated with female sex and presence of other cardiovascular risk factors. Strategic interventions targeting screening and monitoring of renal functions in individuals with DM are urgently needed in this region.

Association between renal function and co-infection with Clonorchis sinensis and Helicobacter pylori: a cross-sectional study

Background

Studies have shown that liver fluke infections may be associated with kidney injury and that Helicobacter pylori (Hp) may be involved in the pathogenesis of kidney diseases. However, no studies have reported the relationship between co-infection with Clonorchis sinensis (Cs) and Hp and renal function. The aim of this study was to examine the relationship between co-infection with Cs and Hp and estimated glomerular filtration rate (eGFR) in a general population, and gender-related differences were also investigated.

Methods

In the cross-sectional study, 4122 subjects from the Health Examination Center of Guangdong Provincial Hospital of Integrated Traditional Chinese and Western Medicine from January 2017 to December 2018 were enrolled. All participants underwent stool examination for the diagnosis of Cs infection and ¹³C-urea breath test (UBT) for the diagnosis of Hp infection. Participants were categorized into four groups: (1) co-infection with Cs and Hp group comprising 207 cases (Hp(+) + Cs(+) group), (2) Cs infection group comprising 1392 cases (Hp(−) + Cs(+)group), (3) Hp infection group comprising 275 cases (Hp(+) + Cs(−) group), and (4) non-infection group comprising 2248 cases (Hp(−) + Cs(−) group). Multiple linear regression analysis was performed to evaluate the relationship between co-infection with Cs and Hp and eGFR.

Results

Hp infection without Cs infection was present in 6.67% (275/4122) of subjects, while Cs infection without Hp infection was present in 33.77% (1392/4122) of subjects. Co-infection with Hp and Cs were present in 5.02% (207/4122) of subjects. Median age of the participants was 43 years (IQR 35–51). Most of the participants were male (2955/4122, 71.69%). Median eGFR was 96.61 ml/min/1.73 m² (IQR 85.05–106.24). Co-infection with Cs and Hp was negatively associated with eGFR after full adjusting (β = − 1.89, 95% CI: − 3.33 to − 0.45, p = 0.01). The relationship remained significant in females (β = − 9.37, 95% CI: − 11.60 to − 7.1, p < 0.001), but not in males.

Conclusion

Our findings suggest that co-infection with Cs and Hp may be associated with reduced renal function in females, but not in males.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-020-05616-0.

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.

Relationship of Renal Function in Mice to Strain, Sex and 177Lutetium-Somatostatin Receptor Ligand Treatment

AIM

 Aim of the study was to establish parameters for 99mTc-MAG3 SPECT renal uptake kinetics in healthy SCID mice as a function of mouse strain and sex and to evaluate the feasibility of this method for detecting 177Lu-somatostatin receptor ligand (177Lu-SRL) treatment effects on kidney function.

MATERIALS AND METHODS

 Dynamic semi-stationary SPECT acquisitions (68 frames, total duration 35 min) was started prior to i. v. injection of 99mTc-MAG3 in 12 female and 12 male SCID mice. Additionally, 6 female SCID mice with neuroendocrine tumors were imaged 1-5 months after 177Lu-SRL (5 DOTATOC, 1 DOTA-JR11) treatment. Kidney function is expressed as maximum time to peak (Tmax), T50 and T25 in minutes (median [interquartile range]). Differences between groups were tested using the Mann-Whitney-U test, and SCID mouse parameters were compared with data for C57BL/6N mice from a recent publication.

RESULTS

 Significant sex-based differences in Tmax between strains were observed (females: C57BL/6N 1.6 [1.4-1.7], SCID 1.4 [1.3-1.5], p = 0.05; males: C57BL/6N 1.4 [1.3-1.4], SCID 1.6 [1.4-1.7], p = 0.04). In C57BL/6N mice, females showed a later Tmax (p < 0.01) than males. SCID mice showed no difference (p = 0.14). Treated SCID mice showed no significant delay in Tmax (2.0 [1.4-2.7], p = 0.15) but a significant delay in T50 (p = 0.02) and T25 (p = 0.01) compared to healthy untreated mice.

CONCLUSION

 This study demonstrated significant sex-related differences between SCID and C57BL/6N mouse strains in kidney function. Establishment of normal values for different strains and sexes therefore is important for experimental therapy studies. Renal SPECT imaging with 99mTc-MAG3 was sufficiently sensitive to detect 177Lu-SRL treatment toxic effects on kidney function in SCID mice.

2-Methoxyestradiol Attenuates Angiotensin II-Induced Hypertension, Cardiovascular Remodeling, and Renal Injury

Estradiol may antagonize the adverse cardiovascular effects of angiotensin II (Ang II). We investigated the effects of 2-methoxyestradiol (2-ME), a nonestrogenic estradiol metabolite, on Ang II-induced cardiovascular and renal injury in male rats. First, we determined the effects of 2-ME on Ang II-induced acute changes in blood pressure, renal hemodynamics, and excretory function. Next, we investigated the effects of 2-ME and 2-hydroxyestardiol (2-HE) on hypertension and cardiovascular and renal injury induced by chronic infusion of Ang II. Furthermore, the effects of 2-ME on blood pressure and cardiovascular remodeling in the constricted aorta (CA) rat model and on isoproterenol-induced (ISO) cardiac hypertrophy and fibrosis were examined. 2-ME had no effects on Ang II-induced acute changes in blood pressure, renal hemodynamics, or glomerular filtration rate. Both 2-ME and 2-HE reduced hypertension, cardiac hypertrophy, proteinuria, and mesangial expansion induced by chronic Ang II infusions. In CA rats, 2-ME attenuated cardiac hypertrophy and fibrosis and reduced elevated blood pressure above the constriction. Notably, 2-ME reduced both pressure-dependent (above constriction) and pressure-independent (below constriction) vascular remodeling. 2-ME had no effects on ISO-induced renin release yet reduced ISO-induced cardiac hypertrophy and fibrosis. This study shows that 2-ME protects against cardiovascular and renal injury due to chronic activation of the renin-angiotensin system. This study reports for the first time that in vivo 2-ME reduces trophic (pressure-independent) effects of Ang II and related cardiac and vascular remodeling.

Neighborhood Food Outlet Access and Dietary Intake among Adults with Chronic Kidney Disease: Results from the Chronic Renal Insufficiency Cohort Study

BACKGROUND

Healthy diet is essential in the management of chronic kidney disease (CKD) and preventing related comorbidities. Food outlet access has been studied in the general population; however, the influence of the local food environment on dietary intake among people with CKD has not been evaluated.

OBJECTIVES

This study examined the associations of food outlet density and type of outlets with dietary intake in a multicenter cohort of racially and ethnically diverse patients with CKD.

METHODS

The Chronic Renal Insufficiency Cohort Study is a multicenter prospective study of patients with CKD that used a validated food frequency questionnaire to capture dietary intake at the baseline visit. This is a cross-sectional analysis of 2,484 participants recruited in 2003-2006 from seven Chronic Renal Insufficiency Cohort Study centers. Food outlet data were used to construct a count of the number of fast-food restaurants, convenience stores, and grocery stores per 10,000 population for each geocoded census block group. Multivariable linear and logistic regression models were used to evaluate the associations between measures of food outlet availability and dietary factors.

RESULTS

The proportion of participants living in zero-, low-, and high-food outlet density areas differed by gender, race or ethnicity, and income level. Among male subjects, living in areas with zero or the highest number of outlets was associated with having the highest caloric intakes in multivariable models. Male subjects living in areas with zero outlets consumed the highest levels of sodium and phosphorous. Female subjects living in areas with zero outlets had the lowest average intake of calories, sodium, and phosphorous. Among low-income female subjects, close proximity to more outlets was associated with higher calorie consumption. Among all participants, access to fast-food restaurants was not associated with an unhealthy diet score, and access to grocery stores was not associated with a healthy diet score.

CONCLUSIONS

Average caloric and nutrient intakes differed by outlet availability; however, there were no strong associations with type of food outlet. This should be considered when developing food-focused public health policies.

Is There a Gender Difference in Clinical Presentation of Renal Hyperparathyroidism and Outcome after Parathyroidectomy?

Introduction

Gender has been proven to influence the pathophysiology and treatment of numerous diseases, including kidney diseases and hormonal dysfunction like hyperparathyroidism. Thus, higher parathormone levels have been demonstrated in women with end-stage kidney disease, when compared to men.

Objectives

We questioned whether female gender is associated with an increased risk for parathyroid nodular hyperplasia and necessary parathyroidectomy in dialysis patients and assessed demographics as well as outcome data for women and men undergoing parathyroidectomy for renal hyperparathyroidism.

Patients and Methods

One hundred and thirty patients (men = 75, female = 55) with end-stage renal disease on chronic dialysis and advanced secondary hyperparathyroidism who underwent parathyroidectomy between 2008 and 2014 at our center were analyzed retrospectively. Perioperative characteristics and short-term outcome were evaluated with respect to biological gender.

Results

No differences could be demonstrated for patient demography, comorbidities and the perioperative course between males and females. Only preoperative calcium levels were lower in female than in male patients (2.3 ± 0.19 vs. 2.3 ± 0.26, p = 0.04). There were more women, however, with cerebrovascular complications during follow-up (p = 0.04). There was no postoperative mortality, and all complications and comorbidities with exception of cerebrovascular diseases were equally distributed between female and male patients.

Conclusion

Overall, we could not demonstrate many significant differences between male and female patients with end-stage renal diseases, chronic dialysis and operated secondary hyperparathyroidism. Only preoperative electrolyte levels were higher in male than in female patients, and cerebrovascular complications developed more often in females than in males during long-term follow-up.

Sex and Glomerular Filtration Rate Trajectories in Children

BACKGROUND AND OBJECTIVES

Differences in CKD progression by sex have been hypothesized to explain disparities in access to kidney transplantation in children. This study aims to identify distinct trajectories of eGFR decline and to investigate the association of sex with eGFR decline.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We used data from the CKD in Children study. Latent class mixed models were used to identify eGFR trajectories and patient characteristics were compared between trajectories. Progression was studied to two outcomes: ESKD (dialysis or transplantation) and a combined outcome of ESKD or 50% eGFR decline from baseline, using multivariable parametric failure time models.

RESULTS

Among 888 patients, 613 with nonglomerular and 275 with glomerular diseases, we observed four and two distinct GFR trajectories, respectively. Among patients with nonglomerular diseases, there was a higher proportion of males in the group with a low baseline GFR. This group had an increased risk of ESKD or 50% GFR decline, despite a similar absolute decline in GFR. Eight patients with nonglomerular diseases, mostly males with obstructive uropathies, had a more rapid absolute GFR decline. However, the association between male sex and rapid absolute GFR decline was NS after adjustment for age, baseline GFR, and proteinuria. Among patients with glomerular diseases, a subgroup including mostly females with systemic immunologic diseases or crescentic GN had a rapid absolute GFR decline.

CONCLUSIONS

This study identifies different trajectories of CKD progression in children and found a faster progression of CKD in females in patients with glomerular diseases, but no significant sex difference in patients with nonglomerular diseases. The differences in progression seem likely explained by sex differences in the underlying primary kidney disease and in baseline GFR rather than by a direct effect of sex on progression.

Kidney Function Decline among Black Patients with Sickle Cell Trait and Sickle Cell Disease: An Observational Cohort Study

BACKGROUND

Sickle cell trait and sickle cell disease are thought to be independent risk factors for CKD, but the trajectory and predictors of kidney function decline in patients with these phenotypes are not well understood.

METHODS

Our multicenter, observational study used registry data (collected January 2005 through June 2018) and included adult black patients with sickle cell trait or disease (exposures) or normal hemoglobin phenotype (reference) status (ascertained by electrophoresis) and at least 1 year of follow-up and three eGFR values. We used linear mixed models to evaluate the difference in the mean change in eGFR per year.

RESULTS

We identified 1251 patients with sickle cell trait, 230 with sickle cell disease, and 8729 reference patients, with a median follow-up of 8 years. After adjustment, eGFR declined significantly faster in patients with sickle cell trait or sickle cell disease compared with reference patients; it also declined significantly faster in patients with sickle cell disease than in patients with sickle cell trait. Male sex, diabetes mellitus, and baseline eGFR ≥90 ml/min per 1.73 m2 were associated with faster eGFR decline for both phenotypes. In sickle cell trait, low hemoglobin S and elevated hemoglobin A were associated with faster eGFR decline, but elevated hemoglobins F and A2 were renoprotective.

CONCLUSIONS

Sickle cell trait and disease are associated with faster eGFR decline in black patients, with faster decline in sickle cell disease. Low hemoglobin S was associated with faster eGFR decline in sickle cell trait but may be confounded by concurrent hemoglobinopathies. Prospective and mechanistic studies are needed to develop best practices to attenuate eGFR decline in such patients.

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 and the kidneys: current understanding and research opportunities

Concerns regarding sex differences are increasingly pertinent in scientific and societal arenas. Although biological sex and socio-cultural gender are increasingly recognized as important modulators of renal function under physiological and pathophysiological conditions, gaps remain in our understanding of the mechanisms underlying sex differences in renal pathophysiology, disease development, progression and management. In this Perspectives article, we discuss specific opportunities for future research aimed at addressing these knowledge gaps. Such opportunities include the development of standardized core data elements and outcomes related to sex for use in clinical studies to establish a connection between sex hormones and renal disease development or progression, development of a knowledge portal to promote fundamental understanding of physiological differences between male and female kidneys in animal models and in humans, and the creation of new or the development of existing resources and datasets to make them more readily available for interrogation of sex differences. These ideas are intended to stimulate thought and interest among the renal research community as they consider sex as a biological variable in future research projects.

Sex Differences in the Progression of CKD Among Older Patients: Pooled Analysis of 4 Cohort Studies

RATIONALE & OBJECTIVE

Data for the association of sex with chronic kidney disease (CKD) progression are conflicting, a relationship this study sought to examine.

STUDY DESIGN

Pooled analysis of 4 Italian observational cohort studies.

SETTING & PARTICIPANTS

1,311 older men and 1,024 older women with estimated glomerular filtration rate (eGFR)<45mL/min/1.73m² followed up in renal clinics.

PREDICTOR

Sex.

OUTCOMES

End-stage kidney disease (ESKD), defined as maintenance dialysis or kidney transplantation, as the primary outcome; all-cause mortality and eGFR decline as secondary outcomes.

ANALYTICAL APPROACH

Cox proportional hazard analysis to estimate the relative risk for ESKD and mortality and linear mixed models to estimate the rate of eGFR decline.

RESULTS

Age, systolic blood pressure, and use of renin-angiotensin system inhibitors were similar in men and women. Baseline eGFRs were 27.6±10.2 in men and 26.0±10.6mL/min/1.73m² in women (P<0.001), while median proteinuria was lower in women (protein excretion, 0.45 [IQR, 0.14-1.10] g/d) compared with men (0.69 [IQR 0.19-1.60] g/d; P<0.001). During a median follow-up of 4.2 years, 757 developed ESKD (59.4% men) and 471 died (58.4% men). The adjusted risks for ESKD and mortality were higher in men (HRs of 1.50 [95% CI, 1.28-1.77] and 1.30 [95% CI, 1.06-1.60], respectively). This finding was consistent across CKD stages. We observed a significant interaction between sex and proteinuria, with the risk for ESKD in men being significantly greater than for women at a level of proteinuria of ∼0.5g/d or greater. The slope of decline in eGFR was steeper in men (-2.09; 95% CI, -2.21 to-1.97mL/min/1.73m² per year) than in women (-1.79; 95% CI, -1.92 to-1.66mL/min/1.73m² per year; P<0.001). Although sex differences in eGFR decline were not different across CKD stages (P=0.3), the difference in slopes between men and women was progressively larger with proteinuria >0.5g/d (P = 0.04).

LIMITATIONS

Residual confounding; only whites were included.

CONCLUSIONS

Excess renal risk in men may, at least in part, be related to higher levels of proteinuria in men compared with women.

Impact of ET-1 and sex in glomerular hyperfiltration in humanized sickle cell mice

Hyperfiltration, highly prevalent early in sickle cell disease (SCD), is in part driven by an increase in ultrafiltration coefficient (K_f). The increase in K_f may be due to enlarged filtration surface area and/or increased glomerular permeability (P_alb). Previous studies have demonstrated that endothelin-1 (ET-1) contributes to P_alb changes in models of diabetes and SCD. Thus, we performed longitudinal studies of renal function to determine the relationship between ET-1 and glomerular size and P_alb that may contribute to hyperfiltration in humanized sickle cell (HbSS) and control (HbAA) mice at 8-32 weeks of age. HbSS mice were characterized by significant increases in plasma and glomerular ET-1 expression in both sexes although this increase was significantly greater in males. HbSS glomeruli of both males and females presented with a progressive and significant increase in glomerular size, volume, and K_f During the onset of hyperfiltration, plasma and glomerular ET-1 expression were associated with a greater increase in glomerular size and K_f in HbSS mice, regardless of sex. The pattern of P_alb augmentation during the hyperfiltration was also associated with an increase in glomerular ET-1 expression, in both male and female HbSS mice. However, the increase in P_alb was significantly greater in males and delayed in time in females. Additionally, selective endothelin A receptor (ET_A) antagonist prevented hyperfiltration in HbSS, regardless of sex. These results suggest that marked sex disparity in glomerular hyperfiltration may be driven, in part, by ET-1-dependent ultra-structural changes in filtration barrier components contributing to glomerular hyperfiltration in HbSS mice.

Solitary kidney and risk of chronic kidney disease

The renal outcome of solitary kidney remains controversial. We examined the longitudinal association of congenital or acquired solitary kidney with the development of chronic kidney disease (CKD). A cohort study was performed involving 271,171 Korean men and women free of CKD at baseline who underwent a health screening program and who were followed annually or biennially for an average of 5.4 years. Solitary kidney was determined based on ultrasonographic findings. CKD was defined as an estimated glomerular filtration rate of < 60 ml/min/1.73 m² and/or the presence of proteinuria in two or more consecutive visits. During 1,472,519.6 person-years of follow-up, 2989 participants developed CKD (incidence rate: 2.0 per 1000 person-years). After adjustment for potential confounders, the aHR (95% CIs) for incident CKD comparing solitary kidney to the control was 3.26 (1.63-6.54). In analyses of cause-specific solitary kidney, aHR (95% CIs) for CKD comparing unilateral nephrectomy and congenital solitary kidney to the control were 6.18 (2.31-16.49) and 2.22 (0.83-5.92), respectively. The association between solitary kidney and CKD was stronger in men. Having a solitary kidney was independently associated with an increased risk of CKD development. Therefore, preventive strategies for reducing the risk of CKD are required in individuals with a solitary kidney.

The Homeodomain Transcription Factor NKX3.1 Modulates Bladder Outlet Obstruction Induced Fibrosis in Mice

Fibrosis is an irreversible remodeling process characterized by the deposition of collagen in the extracellular matrix of various organs through a variety of pathologies in children, leading to the stiffening of healthy tissues and organ dysfunction. Despite the prevalence of fibrotic disease in children, large gaps exist in our understanding of the mechanisms that lead to fibrosis, and there are currently no therapies to treat or reverse it. We previously observed that castration significantly reduces fibrosis in the bladders of male mice that have been partially obstructed. Here, we investigated if the expression of androgen response genes were altered in mouse bladders after partial bladder outlet obstruction (PO). Using a QPCR microarray and QRTPCR we found that PO was sufficient to increase expression of the androgen response gene Nkx3.1. Consistent with this was an increase in the expression of NKX3.1 protein. Immunofluorescent antibody localization demonstrated nuclear NKX3.1 in most bladder cells after PO. We tested if genetic deletion of Nkx3.1 alters remodeling of the bladder wall after PO. After PO, Nkx3.1 ^KO/KO bladders underwent remodeling, demonstrating smaller bladder area, thickness, and bladder: body weight ratios than obstructed, wild type controls. Remarkably, Nkx3.1 ^KO/KO specifically affected histological parameters of fibrosis, including reduced collagen to muscle ratio. Loss of Nkx3.1 altered collagen and smooth muscle cytoskeletal gene expression following PO which supported our histologic findings. Together these findings indicated that after PO, Nkx3.1 expression is induced in the bladder and that it mediates important pathways that lead to tissue fibrosis. As Nkx3.1 is an androgen response gene, our data suggest a possible mechanism by which fibrosis is mediated in male mice and opens the possibility of a molecular pathway mediated by NKX3.1 that could explain sexual dimorphism in bladder fibrosis.

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.

CKD in Patients with Bilateral Oophorectomy

BACKGROUND AND OBJECTIVES

Premenopausal women who undergo bilateral oophorectomy are at a higher risk of morbidity and mortality. Given the potential benefits of estrogen on kidney function, we hypothesized that women who undergo bilateral oophorectomy are at higher risk of CKD.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We performed a population-based cohort study of 1653 women residing in Olmsted County, Minnesota who underwent bilateral oophorectomy before age 50 years old and before the onset of menopause from 1988 to 2007. These women were matched by age (±1 year) to 1653 referent women who did not undergo oophorectomy. Women were followed over a median of 14 years to assess the incidence of CKD. CKD was primarily defined using eGFR (eGFR<60 ml/min per 1.73 m2 on two occasions >90 days apart). Hazard ratios were derived using Cox proportional hazards models, and absolute risk increases were derived using Kaplan-Meier curves at 20 years. All analyses were adjusted for 17 chronic conditions present at index date, race, education, body mass index, smoking, age, and calendar year.

RESULTS

Women who underwent bilateral oophorectomy had a higher risk of eGFR-based CKD (211 events for oophorectomy and 131 for referent women; adjusted hazard ratio, 1.42; 95% confidence interval, 1.14 to 1.77; absolute risk increase, 6.6%). The risk was higher in women who underwent oophorectomy at age ≤45 years old (110 events for oophorectomy and 60 for referent women; adjusted hazard ratio, 1.59; 95% confidence interval, 1.15 to 2.19; absolute risk increase, 7.5%).

CONCLUSIONS

Premenopausal women who undergo bilateral oophorectomy, particularly those ≤45 years old, are at higher risk of developing CKD, even after adjusting for multiple chronic conditions and other possible confounders present at index date.

PODCAST

This article contains a podcast at https://www.asn-online.org/media/podcast/CJASN/2018_10_11_CJASNPodcast_18_1.

Activation of mineralocorticoid receptor by ecdysone, an adaptogenic and anabolic ecdysteroid, promotes glomerular injury and proteinuria involving overactive GSK3β pathway signaling

Ecdysone is an arthropod molting hormone and has been marketed as a non-androgenic natural anabolic and adaptogen. However, the safety profile of ecdysone is largely undetermined. After ecdysone treatment for 2 weeks, mice developed albuminuria with histologic signs of glomerular injury, including hypertrophy, mesangial expansion, mild glomerulosclerosis and podocyte injury. A direct glomerulopathic activity of ecdysone seems to contribute, since addition of ecdysone to cultured glomerular cells induced cytopathic changes, including apoptosis, activation of mesangial cells, podocyte shape changes and a decreased expression of podocyte markers. To explore the molecular target responsible for the pathogenic actions, we employed an in silico modeling system of compound-protein interaction and identified mineralocorticoid receptor (MR) as one of the top-ranking proteins with putative interactions with ecdysone. The molecular structure of ecdysone was highly homologous to mineralocorticoids, like aldosterone. Moreover, ecdysone was capable of both inducing and activating MR, as evidenced by MR nuclear accumulation in glomerular cells both in vitro and in vivo following ecdysone treatment. Mechanistically, glycogen synthase kinase (GSK) 3β, which has been recently implicated in pathogenesis of glomerular injury and proteinuria, was hyperactivated in glomeruli in ecdysone-treated mice, concomitant with diverse glomerulopathic changes. In contrast, spironolactone, a selective blockade of MR, largely abolished the cytopathic effect of ecdysone in vitro and attenuated albuminuria and glomerular lesions in ecdysone treated mice, associated with a mitigated GSK3β overactivity in glomeruli. Altogether, ecdysone seems able to activate MR and thereby promote glomerular injury and proteinuria involving overactive GSK3β pathway signaling.

Triiodothyronine attenuates the progression of renal injury in a rat model of chronic kidney disease

This study was designed to investigate whether and how triiodothyronine (T3) affects renal function in an experimental model of chronic kidney disease. Twenty-four female rats were divided into the following groups: sham-operated control group (n = 8), 5/6 nephrectomized group (Nx, n = 8), and 5/6 nephrectomized group treated with T3 for 2 weeks (T3-Nx, n = 8). T3 administration significantly decreased serum levels of urea, creatinine, tumour necrosis factorα, and interleukin-6 compared with serum levels in the Nx group. The levels of malondialdehyde, transforming growth factor β, fibronectin, and collagen IV, as well as the expression of inducible nitric oxide synthase, nuclear factor κB, poly(ADP-ribose) polymerase, caspase-3, and Bax were all significantly decreased, though not normalized, in the remnant kidney of rats in the T3-Nx group compared with Nx rats. Glutathione, heme oxygenase-1 levels, as well as endothelial nitric oxide synthase expression were increased in the remnant kidney of the T3-Nx group. Histological studies revealed focal necrosis of renal tubules associated with inflammatory cell infiltration and fibrosis in the Nx group. These changes were alleviated in T3-Nx rats. This study showed that T3 administration attenuated the clinical and histological signs of renal injury in 5/6 nephrectomized rats by mitigating renal oxidative stress, inflammation, apoptosis, and fibrosis.

Renal vascular response to angiotensin 1-7 in rats: the role of Mas receptor

Recently a cross talk between angiotensin 1-7 (Ang1-7) receptor (MasR) and angiotensin II receptors types 1 and 2 (AT1R and AT2R) has been highlighted. The effects of MasR antagonist (A779) compared to the vehicle on the renal blood flow (RBF) and renal vascular resistance (RVR) responses to Ang1-7 (300 ng/kg/min) infusion in the absence of Ang II receptors in male and female rats were determined at controlled renal perfusion pressure. Ang1-7 infusion did not alter mean arterial pressure in male and female rats. However, A779 compared to vehicle increased RBF (18% vs 3%) and decreased RVR (13% vs 4%) responses to Ang1-7 infusion significantly (P < 0.05) in male when AngII receptors were blocked. Such observation was not occurred in female animals. Finally it was concluded that renal vascular responses to Ang1-7 administration may not be exerted by MasR in male rats, and these responses are not mediated with AngII receptors.

Risk Factors of Renal Involvement Based on Different Manifestations in Patients with Ankylosing Spondylitis

BACKGROUND/AIMS

Renal involvement is one of the most common extra-articular complications caused by ankylosing spondylitis (AS). Most studies have focused on the incidence rate, clinical manifestation and pathology, while risk factors have hardly been investigated. Therefore, the objective of this study was to assess the risk factors of renal involvement in patients with AS.

METHODS

Clinical and biochemical data of 926 AS patients were collected. Based on the manifestations of renal involvement, patients were divided into three groups and the differences in clinical and biochemical characteristics were compared. A group with non-renal involvement served as a control. Multivariable logistic regression was used for analyzing risk factors of renal involvement in AS.

RESULTS

Of the 926 AS patients, 201 patients suffered from renal involvement. Moreover, female AS patients faced a higher risk of hematuria compared to male patients. As indicated by the data obtained from multivariate logistic regression analysis, gender, uric acid (UA), immunoglobulin A (IgA), and serum albumin (ALB) were found to be risk factors of renal involvement in AS. An increase in UA or IgA levels, or a decrease in ALB level can increase the risk of renal involvement with multiple manifestations (more than one manifestation of renal damage). According to our findings, no definite variable was identified as a risk factor of proteinuria in AS patients.

CONCLUSION

In AS patients, UA, IgA, and ALB levels can indicate the risk of renal involvement in AS patient and need to be paid special attention. Furthermore, women are subjected to a higher risk of hematuria.

[Menopause: Hypertension and vascular disease]

Hypertension is the main cardiovascular risk factor affecting 25% of women. Hormone changes and hypertension after menopause may lead to higher target organ damage and cardiovascular disease such as increased arterial stiffness, coronary diseases, chronic heart failure and stroke. The physiopathological mechanisms involved in the development of hypertension and cardiovascular diseases in menopausal women are controversial. There are pharmacokinetic and pharmacodynamic differences in both sexes, the women have more coughing when using the converting-enzyme inhibitors, more cramps when using thiazide diuretics and more oedema in the inferior limbs when using calcium antagonists. The aim of this review is to analyse possible physiopathological mechanisms involved in hypertension after menopause and to gain a better understanding of the biological effects mediated by vascular ageing in women when the level of oestrogen protective effect decreases over the vascular system.

Sex-specific differences in hypertension and associated cardiovascular disease

Although intrinsic mechanisms that regulate arterial blood pressure (BP) are similar in men and women, marked variations exist at the molecular, cellular and tissue levels. These physiological disparities between the sexes likely contribute to differences in disease onset, susceptibility, prevalence and treatment responses. Key systems that are important in the development of hypertension and cardiovascular disease (CVD), including the sympathetic nervous system, the renin-angiotensin-aldosterone system and the immune system, are differentially activated in males and females. Biological age also contributes to sexual dimorphism, as premenopausal women experience a higher degree of cardioprotection than men of similar age. Furthermore, sex hormones such as oestrogen and testosterone as well as sex chromosome complement likely contribute to sex differences in BP and CVD. At the cellular level, differences in cell senescence pathways may contribute to increased longevity in women and may also limit organ damage caused by hypertension. In addition, many lifestyle and environmental factors - such as smoking, alcohol consumption and diet - may influence BP and CVD in a sex-specific manner. Evidence suggests that cardioprotection in women is lost under conditions of obesity and type 2 diabetes mellitus. Treatment strategies for hypertension and CVD that are tailored according to sex could lead to improved outcomes for affected patients.

Relaxin contributes to the regulation of arterial pressure in adult female mice

Relaxin is increasingly being recognized as a potent vasodilatory and antifibrotic hormone. Given that relaxin is present in the circulation during the luteal phase of the menstrual cycle and during pregnancy, when arterial pressure is lowest in women, relaxin may contribute to the relative cardiovascular protection observed in premenopausal women as compared with age-matched men and postmenopausal women. In the present study, we investigated the contribution of relaxin to the normal regulation of arterial pressure in adult female and male mice and during pregnancy. Mean arterial pressure (MAP) was measured via radiotelemetry in 14-week-old male and female wild-type (WT; C67BL/6xSv129) and relaxin knockout (KO) mice. Thereafter, female mice were time-mated with a (non-telemetered) male of the same genotype and MAP was measured throughout gestation. Basal MAP was ∼10 mmHg lower in WT females than males (P<0.05). Relaxin deficiency increased basal MAP in females (P<0.05 vs WT female), but not males. As expected, MAP decreased during gestation in WT mice. Conversely, in relaxin KO mice, arterial pressure increased during mid and late gestation (P<0.05 as compared with WT). Moreover, relaxin deficiency impaired gestational weight gain and reduced litter size. This is the first study to (i) demonstrate that relaxin contributes to the sexual dimorphism of arterial pressure in mice and (ii) document the changes in the arterial pressure profile of pregnant relaxin KO mice. Understanding the mechanisms that underlie the regulation of arterial pressure in premenopausal females may uncover new strategies to treat hypertension in women (non-pregnant and pregnant) and men.

Urinary Neutrophil Gelatinase-Associated Lipocalin Is Complementary to Albuminuria in Diagnosis of Early-Stage Diabetic Kidney Disease in Type 2 Diabetes

BACKGROUND

Two clinical phenotypes of diabetic kidney disease (DKD) have been reported, that is, with or without increased albuminuria. The aim of study was to assess the usefulness of urinary neutrophil gelatinase-associated lipocalin (uNGAL) for the early diagnosis of DKD in the type 2 diabetes mellitus (T2DM).

METHODS

The study group consisted of 123 patients with T2DM (mean age 62 ± 14 years), with urine albumin/creatinine ratio (uACR) < 300 mg/g and eGFR ≥ 60 ml/min/1.73 m2. The control group included 22 nondiabetic patients with comparable age, sex, and comorbidities. uNGAL, albumin, and creatinine were measured in the first morning urine samples. uACR and uNGAL/creatinine ratios (uNCR) were calculated.

RESULTS

In the control group, maximum uNCR was 39.64 µg/g. In T2DM group, 24 patients (20%) had higher results, with the maximum value of 378.6 µg/g. Among patients with uNCR > 39.64 µg/g, 13 (54%) did not have markedly increased albuminuria. Women with T2DM had higher uNCR than men (p < 0.001), without difference in uACR (p = 0.09). uNCR in T2DM patients correlated significantly with HbA1c. Sex, total cholesterol, and uACR were independent predictors of uNCR above 39.64 µg/g.

CONCLUSIONS

Increased uNGAL and uNCR may indicate early tubular damage, associated with dyslipidemia and worse diabetes control, especially in females with T2DM.

Prediction of new onset of end stage renal disease in Chinese patients with type 2 diabetes mellitus - a population-based retrospective cohort study

BACKGROUND

Since diabetes mellitus (DM) is the leading cause of end stage renal disease (ESRD), this study aimed to develop a 5-year ESRD risk prediction model among Chinese patients with Type 2 DM (T2DM) in primary care.

METHODS

A retrospective cohort study was conducted on 149,333 Chinese adult T2DM primary care patients without ESRD in 2010. Using the derivation cohort over a median of 5 years follow-up, the gender-specific models including the interaction effect between predictors and age were derived using Cox regression with a forward stepwise approach. Harrell's C-statistic and calibration plot were applied to the validation cohort to assess discrimination and calibration of the models.

RESULTS

Prediction models showed better discrimination with Harrell's C-statistics of 0.866 (males) and 0.862 (females) and calibration power from the plots than other established models. The predictors included age, usages of anti-hypertensive drugs, anti-glucose drugs, and Hemogloblin A1c, blood pressure, urine albumin/creatinine ratio (ACR) and estimated glomerular filtration rate (eGFR). Specific predictors for male were smoking and presence of sight threatening diabetic retinopathy while additional predictors for female included longer duration of diabetes and quadratic effect of body mass index. Interaction factors with age showed a greater weighting of insulin and urine ACR in younger males, and eGFR in younger females.

CONCLUSIONS

Our newly developed gender-specific models provide a more accurate 5-year ESRD risk predictions for Chinese diabetic primary care patients than other existing models. The models included several modifiable risk factors that clinicians can use to counsel patients, and to target at in the delivery of care to patients.

Sex and gender differences in chronic kidney disease: progression to end-stage renal disease and haemodialysis

Sex and gender differences are of fundamental importance in most diseases, including chronic kidney disease (CKD). Men and women with CKD differ with regard to the underlying pathophysiology of the disease and its complications, present different symptoms and signs, respond differently to therapy and tolerate/cope with the disease differently. Yet an approach using gender in the prevention and treatment of CKD, implementation of clinical practice guidelines and in research has been largely neglected. The present review highlights some sex- and gender-specific evidence in the field of CKD, starting with a critical appraisal of the lack of inclusion of women in randomized clinical trials in nephrology, and thereafter revisits sex/gender differences in kidney pathophysiology, kidney disease progression, outcomes and management of haemodialysis care. In each case we critically consider whether apparent discrepancies are likely to be explained by biological or psycho-socioeconomic factors. In some cases (a few), these findings have resulted in the discovery of disease pathways and/or therapeutic opportunities for improvement. In most cases, they have been reported as merely anecdotal findings. The aim of the present review is to expose some of the stimulating hypotheses arising from these observations as a preamble for stricter approaches using gender for the prevention and treatment of CKD and its complications.

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.