Gender and the prevalence and progression of renal disease

Aberrant bowel movement frequencies coincide with increased microbe-derived blood metabolites associated with reduced organ function

Bowel movement frequency (BMF) directly impacts the gut microbiota and is linked to diseases like chronic kidney disease or dementia. In particular, prior work has shown that constipation is associated with an ecosystem-wide switch from fiber fermentation and short-chain fatty acid production to more detrimental protein fermentation and toxin production. Here, we analyze multi-omic data from generally healthy adults to see how BMF affects their molecular phenotypes, in a pre-disease context. Results show differential abundances of gut microbial genera, blood metabolites, and variation in lifestyle factors across BMF categories. These differences relate to inflammation, heart health, liver function, and kidney function. Causal mediation analysis indicates that the association between lower BMF and reduced kidney function is partially mediated by the microbially derived toxin 3-indoxyl sulfate (3-IS). This result, in a generally healthy context, suggests that the accumulation of microbiota-derived toxins associated with abnormal BMF precede organ damage and may be drivers of chronic, aging-related diseases.

Burden and risk profile of acute kidney injury in severe COVID-19 pneumonia admissions: a Finding from Jimma University medical center, Ethiopia

BACKGROUND

Acute kidney injury (AKI) is a serious complication of the Corona Virus Disease of 2019 (COVID-19). However, data on its magnitude and risk factors among hospitalized patients in Ethiopia is limited. This study aimed to determine the magnitude of AKI and associated factors among patients admitted for severe COVID-19 pneumonia.

METHODS

An institution-based retrospective cross-sectional study was conducted among 224 patients admitted to Jimma University Medical Center in Ethiopia for severe COVID-19 pneumonia from May 2020 to December 2021. Systematic random sampling was used to select study participants. Medical records were reviewed to extract sociodemographic, clinical, laboratory, therapeutic, and comorbidity data. Bivariable and multivariable logistic regressions were performed to examine factors associated with AKI. The magnitude of the association between the explanatory variables and AKI was estimated using an adjusted odds ratio (AOR) with a 95% confidence interval (CI), and significance was declared at a p-value of 0.05.

RESULTS

The magnitude of AKI was 42% (95% CI: 35.3-48.2%) in the study area. Mechanical ventilation, vasopressors, and antibiotics were required in 32.6, 3.7, and 97.7% of the patients, respectively. After adjusting for possible confounders, male sex (AOR 2.79, 95% CI: 1.3-6.5), fever (AOR 6.5, 95% CI: 2.7-15.6), hypoxemia (AOR 5.1, 95% CI: 1.4-18.9), comorbidities (AOR 2.8, 95% CI: 1.1-7.0), and severe anemia (AOR 10, 95% CI: 1.7-65.7) remained significantly associated with higher odds of AKI.

CONCLUSION

The burden of AKI among patients with severe COVID-19 pneumonia is high in our setting. Male sex, abnormal vital signs, chronic conditions, and anemia can identify individuals at increased risk and require close monitoring and prevention efforts.

Generally-healthy individuals with aberrant bowel movement frequencies show enrichment for microbially-derived blood metabolites associated with reduced kidney function

Bowel movement frequency (BMF) has been linked to changes in the composition of the human gut microbiome and to many chronic conditions, like metabolic disorders, neurodegenerative diseases, chronic kidney disease (CKD), and other intestinal pathologies like irritable bowel syndrome and inflammatory bowel disease. Lower BMF (constipation) can lead to compromised intestinal barrier integrity and a switch from saccharolytic to proteolytic fermentation within the microbiota, giving rise to microbially-derived toxins that may make their way into circulation and cause damage to organ systems. However, the connections between BMF, gut microbial metabolism, and the early-stage development and progression of chronic disease remain underexplored. Here, we examined the phenotypic impact of BMF variation in a cohort of generally-healthy, community dwelling adults with detailed clinical, lifestyle, and multi-omic data. We showed significant differences in microbially-derived blood plasma metabolites, gut bacterial genera, clinical chemistries, and lifestyle factors across BMF groups that have been linked to inflammation, cardiometabolic health, liver function, and CKD severity and progression. We found that the higher plasma levels of 3-indoxyl sulfate (3-IS), a microbially-derived metabolite associated with constipation, was in turn negatively associated with estimated glomerular filtration rate (eGFR), a measure of kidney function. Causal mediation analysis revealed that the effect of BMF on eGFR was significantly mediated by 3-IS. Finally, we identify self-reported diet, lifestyle, and psychological factors associated with BMF variation, which indicate several common-sense strategies for mitigating constipation and diarrhea. Overall, we suggest that aberrant BMF is an underappreciated risk factor in the development of chronic diseases, even in otherwise healthy populations.

Advances in pediatric acute kidney injury pathobiology: a report from the 26th Acute Disease Quality Initiative (ADQI) conference

BACKGROUND

In the past decade, there have been substantial advances in our understanding of the pathobiology of pediatric acute kidney injury (AKI). In particular, animal models and studies focused on the relationship between kidney development, nephron number, and kidney health have identified a number of heterogeneous pathophysiologies underlying AKI. Despite this progress, gaps remain in our understanding of the pathobiology of pediatric AKI.

METHODS

During the 26th Acute Disease Quality Initiative (ADQI) Consensus conference, a multidisciplinary group of experts discussed the evidence and used a modified Delphi process to achieve consensus on recommendations for opportunities to advance translational research in pediatric AKI. The current state of research understanding as well as gaps and opportunities for advancement in research was discussed, and recommendations were summarized.

RESULTS

Consensus was reached that to improve translational pediatric AKI advancements, diverse teams spanning pre-clinical to epidemiological scientists must work in concert together and that results must be shared with the community we serve with patient involvement. Public and private research support and meaningful partnerships with adult research efforts are required. Particular focus is warranted to investigate the pediatric nuances of AKI, including the effect of development as a biological variable on AKI incidence, severity, and outcomes.

CONCLUSIONS

Although AKI is common and associated with significant morbidity, the biologic basis of the disease spectrum throughout varying nephron developmental stages remains poorly understood. An incomplete understanding of factors contributing to kidney health, the diverse pathobiologies underlying AKI in children, and the historically siloed approach to research limit advances in the field. The recommendations outlined herein identify gaps and outline a strategic approach to advance the field of pediatric AKI via multidisciplinary translational research.

Machine-learning model for predicting oliguria in critically ill patients

This retrospective cohort study aimed to develop and evaluate a machine-learning algorithm for predicting oliguria, a sign of acute kidney injury (AKI). To this end, electronic health record data from consecutive patients admitted to the intensive care unit (ICU) between 2010 and 2019 were used and oliguria was defined as a urine output of less than 0.5 mL/kg/h. Furthermore, a light-gradient boosting machine was used for model development. Among the 9,241 patients who participated in the study, the proportions of patients with urine output < 0.5 mL/kg/h for 6 h and with AKI during the ICU stay were 27.4% and 30.2%, respectively. The area under the curve (AUC) values provided by the prediction algorithm for the onset of oliguria at 6 h and 72 h using 28 clinically relevant variables were 0.964 (a 95% confidence interval (CI) of 0.963-0.965) and 0.916 (a 95% CI of 0.914-0.918), respectively. The Shapley additive explanation analysis for predicting oliguria at 6 h identified urine values, severity scores, serum creatinine, oxygen partial pressure, fibrinogen/fibrin degradation products, interleukin-6, and peripheral temperature as important variables. Thus, this study demonstrates that a machine-learning algorithm can accurately predict oliguria onset in ICU patients, suggesting the importance of oliguria in the early diagnosis and optimal management of AKI.

Are Differences in Living Kidney Donation Rates a Sex or a Gender Disparity?

Sex-disaggregated data reveal significant disparities in living kidney donation, with more female than male living kidney donors in most countries and proportions over 60% in some countries. We summarize the present state of knowledge with respect to the potential drivers of this disparity and argue that it is primarily driven by gender-related factors. First, we present the differences between sex and gender and then proceed to summarize the potential medical reasons that have been proposed to explain why males are less likely to be living kidney donors than females, such as the higher prevalence of kidney failure in males. We then present counterarguments as to why biological sex differences are not enough to explain lower living kidney donation among males, such as a higher prevalence of chronic kidney disease among females, which could affect donation rates. We argue that gender differences likely provide a better explanation as to why there are more women than men living kidney donors and explore the role of economic and social factors, as well as gender roles and expectations, in affecting living kidney donation among both men and women. We conclude with the need for a gender analysis to explain this complex psychosocial phenomenon in living kidney donation.

Colistin treatment in older adults: why should we know more?

OBJECTIVES

We aimed to investigate the risk factors of colistin-associated nephrotoxicity in patients older than 65 years treated in the palliative care unit.

METHODS

119 palliative care patients who received intravenous colistimethate for at least 7 days were included in the study. The estimated glomerular filtration rate (GFR) was calculated using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) 2021 equation. Data were obtained from the hospital information system.

RESULTS

The mean age of the participants was 76.7 ± 9.9 years and 49.4% were female. Of the 119 patients, 57 had colistin-induced nephropathy (CIN) according to Kidney Disease: Improving Global Outcomes (KDIGO) criteria. The rate of CIN was higher in women than in men. The baseline phosphate level was higher in the CIN (+) group than in the CIN (-) group. The lower GFR values in patients with pneumonia persisted at days 14 and 30, whereas the lower GFR in patients without pneumonia did not. According to multivariate logistic regression, female gender and baseline phosphate level ≥ 4.5 mg/dl were found as independent variables for the development of nephropathy.

CONCLUSIONS

The creatinine levels of the patients with pneumonia and CIN did not improve after nephrotoxicity, whereas the creatinine levels of the other patients without pneumonia and CIN did. Female gender and baseline phosphate were independent risk factors for CIN. Prolonged kidney failure may lead to a more difficult clinical follow-up process for clinicians. Therefore, clinicians should be aware of persistent renal insufficiency in older patients with pneumonia receiving colistimethate.

Association of matrix metalloproteinase-2 gene variants with diabetic nephropathy risk

BACKGROUND

Diabetic nephropathy is a highly destructive microvascular complication of diabetes. Genetic predisposition is involved in the pathogenesis of diabetic nephropathy, with multiple allelic polymorphisms associated with the development and progression of the disease, thereby increasing the overall risk. To date, no study is available that shows the association of matrix metalloproteinase-2 (MMP-2) gene polymorphisms with diabetic nephropathy risk. Thus, we investigated the potential genetic influence of MMP-2 promoter variants in the development of diabetic nephropathy in type 2 diabetic patients.

METHODS

In total, 726 type 2 diabetic patients and 310 healthy controls were included in the study and genotyped for MMP-2, -1306C/T, -790T/G, -1575G/T and -735C/T by real-time PCR. The analysis of the outcomes was performed assuming three genetic models. The threshold for statistical significance was set at 0.05.

RESULTS

The results showed that the minor allele frequency of the -790T/G variant was significantly higher in patients with and without nephropathy compared to controls. Furthermore, the distribution analysis revealed a significant association of the -790T/G variant, in all genetic models, with increased risk of diabetic nephropathy that persisted after adjusting for key covariates. No significant associations between MMP-2, -1306C/T, -1575G/T, -735C/T and the risk of diabetic nephropathy were detected. Haplotype analysis identified two risk haplotypes GCGC and GTAC associated with diabetic nephropathy.

CONCLUSIONS

The present study is the first to demonstrate the allelic and genotypic association of the MMP-2-790T/G variant and two haplotypes with an increased risk of diabetic nephropathy in a Tunisian population with type 2 diabetes.

Sex-specific epigenetic programming in renal fibrosis and inflammation

The growing prevalence of hypertension, heart disease, diabetes, and obesity along with an aging population is leading to a higher incidence of renal diseases in society. Chronic kidney disease (CKD) is characterized mainly by persistent inflammation, fibrosis, and gradual loss of renal function leading to renal failure. Sex is a known contributor to the differences in incidence and progression of CKD. Epigenetic programming is an essential regulator of renal physiology and is critically involved in the pathophysiology of renal injury and fibrosis. Epigenetic signaling integrates intrinsic and extrinsic signals onto the genome, and various environmental and hormonal stimuli, including sex hormones, which regulate gene expression and downstream cellular responses. The most extensively studied epigenetic alterations that play a critical role in renal damage include histone modifications and DNA methylation. Notably, these epigenetic alterations are reversible, making them candidates for potential therapeutic targets for the treatment of renal diseases. Here, we will summarize the current knowledge on sex differences in epigenetic modulation of renal fibrosis and inflammation and highlight some possible epigenetic therapeutic strategies for CKD treatment.

Effect of gender on presentation and outcome of renal colic

OBJECTIVES

To examine gender-related differences in the presentation, management, and outcomes of patients admitted to the emergency department ED with ureteral stones.

METHODS

Retrospective analysis of all patients admitted to the ED at our institution, found to have a ureteral stone on CT. Clinical, laboratory, imaging parameters, and outcomes were collected.

RESULTS

778 patients were admitted with ureteral stones between January 2018 and December 2020. 78% (n = 609) were males and 22% (n = 169) were females. The mean ages were 49.4 (SD 14.4) and 51.6 (SD 15.7) in males and females, respectively (p = 0.08). Female patients presented with a higher body temperature (p = 0.01), pulse rate (p < 0.0001), nausea and vomiting (p < 0.0001), elevated serum C-reactive protein (CRP) (p = 0.002) compared to males. The prevalence of elevated serum creatinine was higher in males (p < 0.0001). Alpha-blockers were recommended on discharge in 54.8% (334) of males, compared to only 29.6% (50) of females (p < 0.0001). Spontaneous stone expulsion was significantly higher in males compared to females (p = 0.01).

CONCLUSIONS

Our results demonstrate that gender does effect presentation and outcome of patients presenting with renal colic. Females were found to have elevated infectious parameters, more nausea and vomiting and a higher incidence of positive urine cultures. Males admitted to the ED were found to have significantly higher serum creatinine levels. Medical expulsive therapy (MET) with alpha-blockers was prescribed significantly less in female patients, which may have resulted in a lower spontaneous stone expulsion rate.

The prevention and treatment of COVID-19 in patients treated with hemodialysis

Patients treated with hemodialysis are often immunocompromised due to concomitant disease. As a result, this population is at high risk of infection and mortality from COVID-19. In addition to symptomatic treatment, a series of antiviral drugs targeting COVID-19 are now emerging. However, these antivirals are used mainly in mild or moderate patients with high-risk factors for progression to severe disease and are not available as pre- or post-exposure prophylaxis for COVID-19. There is a lack of clinical data on the use of anti-COVID-19 drugs, especially in patients treated with hemodialysis, therefore, vaccination remains the main measure to prevent SARS-CoV-2 infection in these patients. Here, we review the clinical features and prognosis of patients on hemodialysis infected with SARS-CoV-2, the main anti-COVID-19 drugs currently available for clinical use, and the safety and efficacy of anti-COVID-19 drugs or COVID-19 vaccination in patients treated with hemodialysis. This information will provide a reference for the treatment and vaccination of COVID-19 in patients treated with hemodialysis and maximize the health benefits of these patients during the outbreak.

Factors Affecting Adherence to Hemodialysis Therapy Among Patients With End-Stage Renal Disease Attending In-Center Hemodialysis in Al-Ahsa Region, Saudi Arabia

Background Chronic kidney disease (CKD) and end-stage renal disease (ESRD) are global health concerns, with ESRD requiring renal replacement therapy (RRT). Hemodialysis is a prevalent modality for RRT. However, access to hemodialysis is challenging for rural patients due to geographical barriers and limited nephrology services. This research aims to identify factors influencing adherence to hemodialysis sessions among rural ESRD patients, addressing travel, healthcare infrastructure, and socioeconomic factors. Materials and methods A cross-sectional study of 154 participants was conducted from July 06 to September 10, 2023 at Al-Jaber Dialysis Center in Al-Ahsa, Saudi Arabia. It included adult CKD patients on hemodialysis who were interviewed to assess factors influencing hemodialysis adherence using a structured questionnaire. Results Our study assessed hemodialysis adherence in 154 patients in Al-Ahsa, Saudi Arabia. Gender distribution was nearly equal (male = 54.5%), with the majority aged 41-60, married, and residing in downtown areas. Hypertension (43.9%) and diabetes (32.3%) were the prevalent comorbidities. Most patients received thrice-weekly dialysis (96.15%), with family cars as the primary transportation mode (55.2%). Hypertension (43.3%) and diabetic nephropathy (40.9%) were the leading causes of CKD. Approximately 26% missed dialysis, with health issues and transportation difficulties being common reasons. Notably, adherence correlated with female gender, lower education, and family car transportation mode. Social support significantly influenced adherence, highlighting its importance in maintaining hemodialysis adherence. Conclusion Our study identified various sociodemographic and dialysis-related factors influencing adherence among hemodialysis patients in the Al-Ahsa region, Saudi Arabia. Notably, factors such as gender, education level, and transportation means significantly influenced adherence. Adequate family and social support were associated with better adherence. These findings highlight the importance of tailored interventions addressing these factors to enhance hemodialysis adherence and ultimately improve patient outcomes in this population.

Association of hyperhomocysteinemia and chronic kidney disease in the general population: a systematic review and meta-analysis

BACKGROUND

Increasing evidence shows that an elevated homocysteine(Hcy) level is associated with an increased risk of chronic kidney disease (CKD). This study systematically evaluated the correlation between homocysteine level and the incidence of CKD reported in cohort and cross-sectional studies.

METHODS

We searched electronic databases and reference lists for relevant articles. 4 cohort studies and 7 cross-sectional studies including 79,416 patients were analyzed in a meta-analysis. Hyperhomocysteinemia was defined as a Hcy level > 15 µmol/L, which was the criterium used in previous studies. Meta-analyses were conducted of literature searches from online databases such as PubMed, Embase, Cochrane and Scopus. Computed pooled adjusted odds ratios with corresponding 95% confidence intervals (95% CI) were used to estimate the risk of new-onset CKD according to Hcy levels in the general population.

RESULTS

People with high Hcy levels were more likely to suffer from CKD than people with normal Hcy levels (pooled OR, 2.09; 95% CI, 1.72-2.55). This positive relationship persisted across different study types such as cohort studies (summary OR, 2.2; 95% CI, 1.55-3.13) and cross-sectional studies (summary OR, 2.07; 95% CI, 1.63-2.63).

CONCLUSIONS

People with hyperhomocysteinemia have a higher incidence of CKD, Hyperhomocysteinemia may also be an independent risk factor for CKD in the general population.

Development and Validation of Prediction Models for All-Cause Mortality and Cardiovascular Mortality in Patients on Hemodialysis: A Retrospective Cohort Study in China

Purpose

This study aimed to develop two predictive nomograms for the assessment of long-term survival status in hemodialysis (HD) patients by examining the prognostic factors for all-cause mortality and cardiovascular (CVD) event mortality.

Patients and methods

A total of 551 HD patients with an average age of over 60 were included in this study. The patients' medical records were collected from our hospital and randomly allocated to two cohorts: the training cohort (n=385) and the validation cohort (n=166). We employed multivariate Cox assessments and fine-gray proportional hazards models to explore the predictive factors for both all-cause mortality and cardiovascular event mortality risk in HD patients. Two nomograms were established based on predictive factors to forecast patients' likelihood of survival for 3, 5, and 8 years. The performance of both models was evaluated using the area under the curve (AUC), calibration plots, and decision curve analysis.

Results

The nomogram for all-cause mortality prediction included seven factors: age ≥ 60, sex (male), history of diabetes and coronary artery disease, diastolic blood pressure, total triglycerides (TG), and total cholesterol (TC). The nomogram for cardiovascular event mortality prediction included three factors: history of diabetes and coronary artery disease, and total cholesterol (TC). Both models demonstrated good discrimination, with AUC values of 0.716, 0.722 and 0.725 for all-cause mortality at 3, 5, and 8 years, respectively, and 0.702, 0.695, and 0.677 for cardiovascular event mortality, respectively. The calibration plots indicated a good agreement between the predictions and the decision curve analysis demonstrated a favorable clinical utility of the nomograms.

Conclusion

Our nomograms were well-calibrated and exhibited significant estimation efficiency, providing a valuable predictive tool to forecast prognosis in HD patients.

Access to treatment in chronic kidney disease, dialysis and transplantation. Is there gender equality?

Sex and gender are often used as synonyms. However, while sex describes only a biological state, gender is a dynamic concept that takes into account psychosocial and cultural aspects of human existence that can change according to place and time. Inequality in medicine has been described in several areas. Among them, gender inequality has been disregarded for many years and is now a matter of concern. Chronic kidney disease (CKD) is a growing epidemic worldwide, affecting approximately 10% of the population. Although both men and women are affected, gender equality, especially in access to different treatments, is a matter of concern. We decided to investigate gender equality in patients with CKD. To this end, we conducted a literature narrative review to determine whether gender inequalities were found in CKD patients in general and in access to different treatment modalities in particular. A non-language restricted search was performed until November 30th 2022 in PubMed, SciELO, Trip Database, Google Scholar, MEDES y MEDLINE. We also investigated the situation in this regard in our country. We found that CKD is more prevalent in women than men, nevertheless this prevalence decreases along the CKD stages to the point that more men reach end stage kidney disease (ESKD) and dialysis. Access to transplant (ATT) is higher in men than in women although posttransplant survival shows no gender differences. Finally, most series have shown that women are more frequently Kidney transplantation (KT) living donors than men. Results in our country are similar to the published literature with the exception of a higher proportion of men as KT living donors. As in other areas, gender inequality in Nephrology has been largely overlooked. In this review we have highlighted gender differences in CKD patients. Gender inequality in Nephrology exists and needs to be looked upon in order to reach a personalized clinical approach.

Kidney disease in patients with chronic liver disease: Does sex matter?

Kidney disease in patients with liver disease is serious and increases mortality. Up to 50% of patients hospitalized experience an episode of acute kidney injury. In general, men with liver disease are thought to be at increased risk of kidney disease. However, this association should be considered with caution because most studies use creatinine-based inclusion criteria, which is negatively biased against women. In this review, we synthesize data on sex differences in kidney disease in patients with chronic liver disease in the clinical setting and discuss potential physiologic underpinnings.

Androgen receptor blockade by flutamide down-regulates renal fibrosis, inflammation, and apoptosis pathways in male rats

AIM

this study aims to explore the effect of androgen receptor (AR) blockade by flutamide on some renal pathologic changes such as inflammation, apoptosis, and fibrosis in male rats.

MAIN METHODS

Firstly, we investigated the potential effect of AR blockade on renal inflammatory intermediates including IL-1β, IL-6, TNF-α, NF-Қβ proteins, and the renal gene expression of NF-Қβ. Besides inflammation, we also assessed the apoptosis pathways including the caspases 3 & 9, mTOR, pAKT proteins, and BAX gene expression. Besides inflammation and apoptosis pathways, we also investigated the effect of androgen blockade on renal fibrosis intermediates including vimentin, TGFβ-1, α-SMA, MMP-9, collagen type-III, collagen type-IV, and the renal expression of the col1A1 gene. Besides previous pathological pathways, we assessed the expression of chloride channel protein-5 (ClC-5), as an important regulator of many renal pathological changes. Finally, we assessed the impact of previous pathological changes on renal function at biochemical and pathological levels.

KEY FINDINGS

We found that AR blockade by flutamide was associated with the down-regulation of renal inflammation, apoptosis, and fibrosis markers. It was associated with expression down-regulation of IL-1β & IL-6, TNF-α, NF-Қβ, caspases 3 & 9, mTOR, MMP-9, collagens, TGFβ-1, and α-SMA. Away from down-regulation, we also found that AR blockade has upregulated ClC-5 and pAKT proteins.

SIGNIFICANCE

AR is a major player in androgens-induced nephrotoxicity. AR blockade downregulates renal fibrosis, inflammation, and apoptosis pathways. It may be helpful as a strategy for alleviation of renal side effects associated with some drugs. However; this needs further investigations.

The programming of kidney injury in offspring affected by maternal overweight and obesity: role of lipid accumulation, inflammation, oxidative stress, and fibrosis in the kidneys of offspring

Maternal overweight and obesity are considered important factors affecting fetal development with many potential consequences for offspring after delivery, including the increased risk of obesity and diabetes mellitus. Maternal obesity promotes adiposity in the offspring by increasing fat deposition and expansion in the body of the offspring. The expansion of adipose tissue changes adipokine levels, including a decrease in adiponectin and an increase in leptin. In addition to changes in adipokine levels, there are also increases in pro-inflammatory cytokines, pro-fibrotic cytokines, and reactive oxygen species, leading to oxidative stress in the offspring. These contribute to the promotion of insulin resistance in offspring, which is associated with kidney injury. Interestingly, maternal obesity can also promote renal lipid accumulation, which could activate inflammatory processes and promote renal oxidative stress and renal fibrosis. These alterations in the kidneys of the offspring imply that a mother being overweight/obese can program the development of kidney disease in offspring. This review will discuss the effects of a mother being overweight or obese on their offspring and the consequences with regard to the kidneys of their offspring. With a focus on the molecular mechanisms, including renal inflammation, renal oxidative stress, renal fibrosis, and renal lipid metabolism in offspring born to overweight and obese mothers, the causative mechanisms and perspective of these conditions will be included.

Impact of hypertension and diabetes on the onset of chronic kidney disease in a general Japanese population

Hypertension (HT) and diabetes mellitus (DM) are both major risk factors for chronic kidney disease (CKD); however, few studies have examined the impacts of the combination of HT and DM on CKD development in general populations. We aimed to explore whether HT or DM contributes more to CKD development in a Japanese community. A total of 5823 individuals without a history of CKD who underwent specific health checkups in fiscal year 2013 were monitored until the end of March 2018. Participants were categorized as having neither HT nor DM (none group), either HT or DM, and both (HT + DM). We calculated the hazard ratios (HRs) for developing CKD in each category using Cox proportional hazards models after adjusting for age, dyslipidemia, smoking, and alcohol drinking and with the none group as the reference. We also estimated the population attributable fraction (PAF) for CKD development in populations with either HT or DM or both. During a mean follow-up of 3.0 years, 759 individuals developed CKD, with HRs of 1.56 with a 95% confidence interval (CI) [1.33, 1.83], 1.22 with a 95% CI [0.86, 1.75], and 2.83 with a 95% CI [2.22, 3.63] for the HT only, DM only and HT + DM categories, respectively. Sex-specific analysis showed similar findings. The PAFs for CKD (14.1% and 17.2% for men and women, respectively) were the highest among participants with HT only. We concluded that in this Japanese community, HT contributed more than DM to CKD development; hence, managing hypertension is important to prevent CKD as well as diabetes.

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.

Predicting the risk of acute kidney injury after cardiopulmonary bypass: development and assessment of a new predictive nomogram

BACKGROUND

Acute kidney injury (AKI) is a common and severe complication of cardiac surgery with cardiopulmonary bypass (CPB). This study aimed to establish a model to predict the probability of postoperative AKI in patients undergoing cardiac surgery with CPB.

METHODS

We conducted a retrospective, multicenter study to analyze 1082 patients undergoing cardiac surgery under CPB. The least absolute shrinkage and selection operator regression model was used to optimize feature selection for the AKI model. Multivariable logistic regression analysis was applied to build a prediction model incorporating the feature selected in the previously mentioned model. Finally, we used multiple methods to evaluate the accuracy and clinical applicability of the model.

RESULTS

Age, gender, hypertension, CPB duration, intraoperative 5% bicarbonate solution and red blood cell transfusion, urine volume were identified as important factors. Then, these risk factors were created into nomogram to predict the incidence of AKI after cardiac surgery under CPB.

CONCLUSION

We developed a nomogram to predict the incidence of AKI after cardiac surgery. This model can be used as a reference tool for evaluating early medical intervention to prevent postoperative AKI.

Biomarkers Involved in the Mineral-Bone Disorders Secondary to Chronic Hemodialysis

Introduction. Chronic kidney disease (CKD) is one of the most prevalent public health problems of the elderly population. End-Stage Renal Disease (ESRD)’s most common treatment is dialysis. There are some dissimilarities between the sexes that are apparent in the status and the possible outcomes of CKD. This study aims to shed some light on these somewhat overlooked wwwvariations and their implications.

Materials and methods. We conducted an observational study on subjects with CKD, undergoing hemodialysis for at least 2 years. For participation, we selected an equal number of men and women, which were divided into 2 groups according to gender. Plasma levels of the following parameters were monitored: creatinine, urea, bicarbonate, phosphorus, calcium, alkaline phosphatase, vitamin D, FGF-23 and TNF-alpha. The differences of the variables between the two groups were evaluated using TTEST and CORREL test.

Results. A significant correlation was between the plasma levels of FGF-23 and gender (p =0.02). Regarding the plasmatic levels of urea, besides the expected difference in pre- and post- dialysis levels, we obtained a significant correlation between its post-dialysis value and gender (p =0.045). In regard to the plasmatic levels of the alkaline phosphatase, there was a significant correlation between its value and gender (p =0.01).

Conclusions. There is a significant correlation between the plasmatic levels of creatinine, urea, alkaline phosphatase, vitamin D, FGF-23 and gender. Women present lower levels of creatinine and urea, while men present lower plasmatic levels of vitamin D, alkaline phosphatase and FGF-23.

Low-dose hydralazine reduces albuminuria and glomerulosclerosis in a mouse model of obesity-related chronic kidney disease

AIM

To determine, using a mouse model of obesity, whether low-dose hydralazine prevents obesity-related chronic kidney disease (CKD).

METHODS

From 8 weeks of age, male C57BL/6 mice received a high-fat diet (HFD) or chow, with or without low-dose hydralazine (25 mg/L) in drinking water, for 24 weeks. Biometric and metabolic variables, renal function and structural changes, renal global DNA methylation, DNA methylation profile and markers of renal fibrosis, injury, inflammation and oxidative stress were assessed.

RESULTS

The HFD-fed mice developed obesity, with glucose intolerance, hyperinsulinaemia and dyslipidaemia. Obesity increased albuminuria and glomerulosclerosis, which were significantly ameliorated by low-dose hydralazine in the absence of a blood pressure-lowering effect. Obesity increased renal global DNA methylation and this was attenuated by low-dose hydralazine. HFD-induced changes in methylation of individual loci were also significantly reversed by low-dose hydralazine. Obese mice demonstrated increased markers of kidney fibrosis, inflammation and oxidative stress, but these markers were not significantly improved by hydralazine.

CONCLUSION

Low-dose hydralazine ameliorated HFD-induced albuminuria and glomerulosclerosis, independent of alterations in biometric and metabolic variables or blood pressure regulation. Although the precise mechanism of renoprotection in obesity is unclear, an epigenetic basis may be implicated. These data support repurposing hydralazine as a novel therapy to prevent CKD progression in obese patients.

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

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

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

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

The Lower Limit of Reference of Urinary Albumin/Creatinine Ratio and the Risk of Chronic Kidney Disease Progression in Patients With Type 2 Diabetes Mellitus

A urine albumin/creatinine ratio (UACR) <30 mg/g is considered to be normal, while increased risk of incident hypertension and cardiovascular disease mortality in subjects with high normal UACR level had been observed. However, a mild elevated but normal UACR level was associated with the risk of initiating chronic kidney disease (CKD) is uncertain. We investigated whether higher normal UACR is associated with the risk of developing CKD. A total of 4821 subjects with type 2 diabetes mellitus (T2DM), an estimated glomerular filtration rate >60 ml/min/1.73 m2 and UACR <30 mg/g enrolled in a diabetes disease management program between 2006 and 2020 were studied. The optimal cutoff point for baseline UACR as a predictor for progression to CKD according to the 2012 KDIGO definition was calculated using receiving operating characteristic curve analysis. After a mean of 4.9 years follow-up, the CKD risk progression increased in parallel with the quartiles of baseline UACR <30 mg/g (p for trend <0.0001). UACR cutoff points of 8.44 mg/g overall, 10.59 mg/g in males and 8.15 mg/g in females were associated with the risk of CKD progression. In multivariate Cox regression analysis, the hazard ratios for the association between UACR (>8.44 mg/g, >10.9 mg/g, >8.15 mg/g in overall, male, and female patients, respectively) and the risk of CKD progression were significant. This study demonstrated that a cutoff UACR value of >10 mg/g could significantly predict the cumulative incidence and progression of CKD in patients with T2DM.

Chronic Kidney Disease in the Transgender, Nonbinary, or Gender Diverse Person

Nephrologists are increasingly providing care to transgender, nonbinary, and gender diverse (TNBGD) individuals with chronic kidney disease. This narrative review discusses the care of TNBGD individuals from a nephrology perspective. TNBGD individuals are under-represented in the nephrology literature. TNBGD individuals are at an increased risk of adverse outcomes compared with the cisgender population including mental health, cardiovascular disease, malignancy, sexually transmitted infections, and mortality. Gender-affirming hormone therapy (GAHT) with estradiol in transfeminine individuals potentially increases the risk of venous thromboembolism and cardiovascular disease. GAHT with testosterone in transmasculine individuals potentially increases the risk of erythrocytosis and requires careful monitoring. GAHT modifies body composition and lean muscle mass, which in turn influence creatinine generation and excretion, which may impact the performance of estimated glomerular filtration rate (GFR) equations and the estimation of 24-hour urine values from spot urine albumin/protein to creatinine ratios. There are limited studies regarding TNBGD individuals with chronic kidney disease. Additional research is needed to evaluate the effects of GAHT on GFR and biomarkers of kidney function and the performance of the estimated GFR equation in TNBGD populations.

Sex and Gender Related Differences in Diabetic Kidney Disease

Diversity in sex and gender are important considerations in the pathogenesis, prognostication, research, and management of diabetic kidney disease (DKD). Sex and gender differences in the disease risk, disease-specific mechanisms, and outcomes in DKD may be attributed to biological differences between males and females at the cellular and tissue level, inconsistencies in the diagnostic and assessment tools used in chronic kidney disease and DKD, as well societal differences in the way men, women, and gender-diverse individuals self-manage and interact with health care systems. This review outlines key considerations related to the impact of sex on DKD, specifically elaborating on how they contribute to observed differences in disease epidemiology, pathogenesis, and treatment strategies. We also highlight the effect of gender on DKD progression and care.

The association between hypertriglyceridemic-waist phenotype and chronic kidney disease: a cohort study and meta-analysis

Evidence on the association between hypertriglyceridemic-waist phenotype (HTGW) and chronic kidney disease (CKD) is limited and inconsistent. We aimed to explore such association among 7406 Chinese aged ≥ 45 years in a cohort setting, followed by a meta-analysis. Participants were categorized into four phenotypes: NTNW (normal triglycerides and normal waist circumference), NTGW (isolated enlarged waist circumference), HTNW (isolated high triglycerides), and HTGW (high triglycerides and enlarged waist circumference). We used multivariate logistic regression to determine the association between different phenotypes and risk of CKD in the cohort study. For meta-analysis, we searched relevant studies from Embase, Medline, PubMed, and Web of Science from dataset inception up to May 1, 2021. A random-effect model was used to estimate the pooled effect and I² statistic was applied to evaluate heterogeneity. In the cohort study, compared to the NTNW phenotype, HTGW (OR 1.82, 95% CI 1.32 to 2.51, p < 0.01) and NTGW (OR 1.48, 95% CI 1.13 to 1.94, p = 0.004) were significantly associated with CKD risk after 4 years follow-up, but not for the HTNW phenotype. The meta-analysis also showed a positive association between HTGW phenotype and CKD risk (pooled OR 1.53, 95% CI 1.31 to 1.79, I² = 62.4%). Assessment of triglyceridemic-waist phenotypes might help to identify individuals with high-risk of developing CKD.

Gender and Ethnic Disparities of Acute Kidney Injury in COVID-19 Infected Patients: A Literature Review

Coronavirus disease 2019(COVID-19) has become a public health emergency of concern worldwide. COVID-19 is a new infectious disease arising from Coronavirus 2 (SARS-CoV-2). It has a strong transmission capacity and can cause severe and even fatal respiratory diseases. It can also affect other organs such as the heart, kidneys and digestive tract. Clinical evidence indicates that kidney injury is a common complication of COVID-19, and acute kidney injury (AKI) may even occur in severely ill patients. Data from China and the United States showed that male sex, Black race, the elderly, chronic kidney disease, diabetes, hypertension, cardiovascular disease, and higher body mass index are associated with COVID-19‐induced AKI. In this review, we found gender and ethnic differences in the occurrence and development of AKI in patients with COVID-19 through literature search and analysis. By summarizing the mechanism of gender and ethnic differences in AKI among patients with COVID-19, we found that male and Black race have more progress to COVID-19-induced AKI than their counterparts.

Is Compensation Prediction Score Valid for Contralateral Kidney After Living-Donor Nephrectomy in the United States?

BACKGROUND

Compensation after living donor nephrectomy is well known, and a compensation prediction score (CPS) was made in Japan previously. The aim of this study was to perform external validation of CPS in the United States.

METHODS

We studied retrospectively 78 living donor nephrectomies in our institution. We defined a favorable compensation as a postdonation estimated glomerular filtration rate (eGFR) at 1 year of >60% of the predonation eGFR. We analyzed the living donors' clinical characteristics and outcomes and validated CPS score.

RESULTS

The median (range) donor age was 43 (21-63) years, and median body mass index was 26.9 (18.3-35.9) kg/m². Forty-four percent of donors were White. The donor predonation eGFR was 105 (61-134) mL/min/1.73 m², and the postdonation eGFR at 1 year was 73.2 (0-115) mL/min/1.73 m². Eighty-three percent of donors had a favorable compensation. The CPS was 9.6 (1.6-15.6) and showed strong diagnostic accuracy for predicting favorable compensation (area under the curve, 0.788; 95% confidence interval, 0.652-0.924; P = .001). The CPS showed a significant positive correlation with the postdonation eGFR at 1 year (R = 0.54; P < .001).

CONCLUSIONS

In the United States, the CPS would be a valid tool with which to predict a favorable compensation of remnant kidney function.

Derivation and Validation of a Prediction Model of End-Stage Renal Disease in Patients With Type 2 Diabetes Based on a Systematic Review and Meta-analysis

OBJECTIVES

To develop and validate a model for predicting the risk of end-stage renal disease (ESRD) in patients with type 2 diabetes.

METHODS

The derivation cohort was from a meta-analysis. Statistically significant risk factors were extracted and combined to the corresponding risk ratio (RR) to establish a risk assessment model for ESRD in type 2 diabetes. All risk factors were scored according to their weightings to establish the prediction model. Model performance is evaluated using external validation cohorts. The outcome was the occurrence of ESRD defined as eGFR<15 ml min^-1 1.73 m^-2 or received kidney replacement therapy (dialysis or transplantation).

RESULTS

A total of 1,167,317 patients with type 2 diabetes were included in our meta-analysis, with a cumulative incidence of approximately 1.1%. The final risk factors of the prediction model included age, sex, smoking, diabetes mellitus (DM) duration, systolic blood pressure (SBP), hemoglobin A1c (HbA1c), estimated glomerular filtration rate (eGFR), and triglyceride (TG). All risk factors were scored according to their weightings, with the highest score being 36.5. External verification showed that the model has good discrimination, AUC=0.807(95%CI 0.753-0.861). The best cutoff value is 16 points, with the sensitivity and specificity given by 85.33% and 60.45%, respectively.

CONCLUSION

The study established a simple risk assessment model including 8 routinely available clinical parameters for predicting the risk of ESRD in type 2 diabetes.

Comparison of the renal effects of bisphenol A in mice with and without experimental diabetes. Role of sexual dimorphism

Bisphenol-A (BPA), a chemical -xenoestrogen- used in the production of the plastic lining of food and beverage containers, is present in the urine of almost the entire population. Recent studies have shown that BPA exposure is associated with podocytopathy, increased urinary albumin excretion (UAE), and hypertension. Since these changes are characteristic of early diabetic nephropathy (DN), we explored the renal effects of BPA and diabetes including the potential role of sexual dimorphism. Male and female mice were included in the following animals' groups: control mice (C), mice treated with 21.2 mg/kg of BPA in the drinking water (BPA), diabetic mice induced by streptozotocin (D), and D mice treated with BPA (D + BPA). Male mice form the D + BPA group died by the tenth week of the study due probably to hydro-electrolytic disturbances. Although BPA treated mice did not show an increase in serum creatinine, as observed in D and D + BPA groups, they displayed similar alteration to those of the D group, including increased in kidney damage biomarkers NGAL and KIM-1, UAE, hypertension, podocytopenia, apoptosis, collapsed glomeruli, as well as TGF-β, CHOP and PCNA upregulation. UAE, collapsed glomeruli, PCNA staining, TGF-β, NGAL and animal survival, significantly impaired in D + BPA animals. Moreover, UAE, collapsed glomeruli and animal survival also displayed a sexual dimorphism pattern. In conclusion, oral administration of BPA is capable of promoting in the kidney alterations that resemble early DN. Further translational studies are needed to clarify the potential role of BPA in renal diseases, particularly in diabetic patients.

Renal morphology and glomerular capillarisation in young adult sheep born moderately preterm

Preterm birth (delivery <37 weeks of gestation) is associated with impaired glomerular capillary growth in neonates; if this persists, it may be a contributing factor in the increased risk of hypertension and chronic kidney disease in people born preterm. Therefore, in this study, we aimed to determine the long-term impact of preterm birth on renal morphology, in adult sheep. Singleton male sheep were delivered moderately preterm at 132 days (~0.9) of gestation (n = 6) or at term (147 days gestation; n = 6) and euthanised at 14.5 months of age (early adulthood). Stereological methods were used to determine mean renal corpuscle and glomerular volumes, and glomerular capillary length and surface area, in the outer, mid and inner regions of the renal cortex. Glomerulosclerosis and interstitial collagen levels were assessed histologically. By 14.5 months of age, there was no difference between the term and preterm sheep in body or kidney weight. Renal corpuscle volume was significantly larger in the preterm sheep than the term sheep, with the preterm sheep exhibiting enlarged Bowman's spaces; however, there was no difference in glomerular volume between groups, with no impact of preterm birth on capillary length or surface area per glomerulus. There was also no difference in interstitial collagen levels or glomerulosclerosis index between groups. Findings suggest that moderate preterm birth does not adversely affect glomerular structure in early adulthood. The enlarged Bowman's space in the renal corpuscles of the preterm sheep kidneys, however, is of concern and merits further research into its cause and functional consequences.

The number of glomeruli and pyruvate metabolism is not strongly coupled in the healthy rat kidney

PURPOSE

The number of glomeruli is different in men and women, as they also present different prevalence and progression of chronic kidney disease. A recent study has demonstrated a potential difference in renal metabolism between sexes, and a potential explanation could be the differences in glomeruli number. This study investigates the potential correlation between glomerular number and pyruvate metabolism in healthy kidneys.

METHODS

This study is an experimental study with rats (N = 12). We used cationized-ferritin MRI to visualize and count glomeruli and hyperpolarized [1-¹³ C]pyruvate to map the metabolism. Dynamic contrast-enhanced MRI was used to analyze kidney hemodynamics using gadolinium tracer.

RESULTS

Data showed no or subtle correlation between the number of glomeruli and the pyruvate metabolism. Minor differences were observed in the number of glomeruli (female = 24,509 vs. male = 26 350; p = .16), renal plasma flow (female = 606.6 vs. male= 455.7 ml/min/100 g; p = .18), and volume of distribution (female = 87.44 vs. male = 76.61 ml/100 ml; p = .54) between sexes. Mean transit time was significantly prolonged in males compared with females (female = 8.868 s vs. male = 10.63 s; p = .04).

CONCLUSION

No strong statistically significant correlation between the number of glomeruli and the pyruvate metabolism was found in healthy rat kidneys.

Association between urinary VEGFA and renal pathology of IgA nephropathy patients

BACKGROUND

Renal biopsy remains the golden standard for diagnosing and monitoring IgA nephropathy (IgAN). Vascular endothelial growth factor A (VEGFA) was crucial for the survival of glomerular cells. Our aim was to screen the expression pattern of urinary, circulating and renal VEGFA in IgAN patients to reveal their relationship with renal pathology and outcomes.

METHODS

Baseline VEGFA levels were determined with ELISA, real-time PCR and immunohistochemistry. Associations between VEGFA expression and clinical-pathological parameters, and renal outcomes were evaluated.

RESULTS

Compared with healthy controls, urinary VEGFA level was obviously elevated in IgAN patients (76.19 ± 63.67 pg/mg Cr vs 146.67 ± 232.71 pg/mg Cr, p = 0.0291) and not correlated with serum VEGFA level. Baseline urinary VEGFA was significantly associated with gender and tubular atrophy/interstitial fibrosis by stepwise multivariate regression analysis. Urinary VEGFA was higher in male patients accompanied with higher serum creatinine, larger proportion of hypertension and recurrent hematuria than in female patients. In the kidney of IgAN patients, VEGFA were robustly expressed in the parietal epithelial cells, podocytes, mesangial cells and tubular epithelial cells. After a follow-up duration of 38.53 ± 27.14 months, IgAN patients with higher urinary VEGFA level were found to have a poorer renal outcome of renal replacement therapy (HR = 1.027, p = 0.037) or composite outcome (HR = 1.023, p = 0.039) after adjusting for confounders.

CONCLUSIONS

Increased urinary VEGFA might reflect certain renal pathology and, although not fully specific, still could be served as a valuable noninvasive indicator in predicting renal progression of IgAN.

Novel Role of Gestational Hydralazine in Limiting Maternal and Dietary Obesity-Related Chronic Kidney Disease

BACKGROUND

Maternal obesity is a risk factor for chronic kidney disease (CKD) in offspring, underpinning the theory of the developmental origins of health and disease. DNA methylation has been implicated in the programming of adult chronic disease by maternal obesity, therefore, DNA demethylating agents may mitigate offspring risk of disease. In rodent models, low-dose hydralazine has previously been shown to reduce renal fibrosis via DNA demethylation. We used mouse models of maternal obesity and offspring obesity to determine whether administration of low-dose hydralazine during gestation can prevent fetal programming of CKD in offspring.

METHODS

Female C57BL/6 mice received high fat diet (HFD) or chow prior to mating, during gestation and lactation. During gestation, dams received subcutaneous hydralazine (5 mg/kg) or saline thrice-weekly. Male offspring weaned to HFD or chow, which continued until endpoint at 32 weeks. Biometric and metabolic parameters, renal global DNA methylation, renal functional and structural changes, and renal markers of fibrosis, inflammation and oxidative stress were assessed at endpoint.

RESULTS

Offspring exposed to maternal obesity or diet-induced obesity had significantly increased renal global DNA methylation, together with other adverse renal effects including albuminuria, glomerulosclerosis, renal fibrosis, and oxidative stress. Offspring exposed to gestational hydralazine had significantly reduced renal global DNA methylation. In obese offspring of obese mothers, gestational hydralazine significantly decreased albuminuria, glomerulosclerosis, and serum creatinine. Obese offspring of hydralazine-treated lean mothers displayed reduced markers of renal fibrosis and oxidative stress.

CONCLUSION

Gestational hydralazine decreased renal global DNA methylation and exerted renoprotective effects in offspring. This supports a potential therapeutic effect of hydralazine in preventing maternal obesity or dietary obesity-related CKD, through an epigenetic mechanism.

British Columbia CARMA-CHIWOS Collaboration (BCC3): protocol for a community-collaborative cohort study examining healthy ageing with and for women living with HIV

INTRODUCTION

Women living with HIV (WLWH) experience accelerated ageing and an increased risk of age-associated diseases earlier in life, compared with women without HIV. This is likely due to a combination of viral factors, gender differences, hormonal imbalance and psychosocial and structural conditions. This interdisciplinary cohort study aims to understand how biological, clinical and sociostructural determinants of health interact to modulate healthy ageing in WLWH.

METHODS AND ANALYSIS

The British Columbia Children and Women: AntiRetroviral therapy and Markers of Aging-Canadian HIV Women's Sexual and Reproductive Health Cohort Study (CARMA-CHIWOS) Collaboration (BCC3) study will enrol WLWH (n=350) and sociodemographically matched HIV-negative women (n=350) living in British Columbia. A subset of BCC3 participants will be past participants of CARMA, n≥1000 women and children living with and without HIV, 2008-2018 and/or CHIWOS, n=1422 WLWH, 2013-2018. Over two study visits, we will collect biological specimens for virus serologies, hormones and biological markers as well as administer a survey capturing demographic and sociostructural-behavioural factors. Sociodemographics, comorbidities, number and type of chronic/latent viral infections and hormonal irregularities will be compared between the two groups. Their association with biological markers and psychostructural and sociostructural factors will be investigated through multivariable regression and structural equation modelling. Retrospective longitudinal analyses will be conducted on data from past CARMA/CHIWOS participants. As BCC3 aims to follow participants as they age, this protocol will focus on the first study visits.

ETHICS AND DISSEMINATION

This study has been approved by the University of British Columbia Children's and Women's Research Ethics Board (H19-00896). Results will be shared in peer-reviewed journals, conferences and at community events as well as at www.hivhearme.ca and @HIV_HEAR_me. WLWH are involved in study design, survey creation, participant recruitment, data collection and knowledge translation. A Community Advisory Board will advise the research team throughout the study.

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.

Renal Inflammation Induces Salt Sensitivity in Male db/db Mice through Dysregulation of ENaC

BACKGROUND

Hypertension is considered a major risk factor for the progression of diabetic kidney disease. Type 2 diabetes is associated with increased renal sodium reabsorption and salt-sensitive hypertension. Clinical studies show that men have higher risk than premenopausal women for the development of diabetic kidney disease. However, the renal mechanisms that predispose to salt sensitivity during diabetes and whether sexual dimorphism is associated with these mechanisms remains unknown.

METHODS

Female and male db/db mice exposed to a high-salt diet were used to analyze the progression of diabetic kidney disease and the development of hypertension.

RESULTS

Male, 34-week-old, db/db mice display hypertension when exposed to a 4-week high-salt treatment, whereas equivalently treated female db/db mice remain normotensive. Salt-sensitive hypertension in male mice was associated with no suppression of the epithelial sodium channel (ENaC) in response to a high-salt diet, despite downregulation of several components of the intrarenal renin-angiotensin system. Male db/db mice show higher levels of proinflammatory cytokines and more immune-cell infiltration in the kidney than do female db/db mice. Blocking inflammation, with either mycophenolate mofetil or by reducing IL-6 levels with a neutralizing anti-IL-6 antibody, prevented the development of salt sensitivity in male db/db mice.

CONCLUSIONS

The inflammatory response observed in male, but not in female, db/db mice induces salt-sensitive hypertension by impairing ENaC downregulation in response to high salt. These data provide a mechanistic explanation for the sexual dimorphism associated with the development of diabetic kidney disease and salt sensitivity.

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

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

Low-dose hydralazine during gestation reduces renal fibrosis in rodent offspring exposed to maternal high fat diet

BACKGROUND

Maternal high fat diet (HFD) promotes chronic kidney disease (CKD) in offspring. This is in accordance with the theory of fetal programming, which suggests adverse conditions occurring in utero predispose offspring to chronic conditions later in life. DNA methylation has been proposed as a key mechanism by which fetal programming occurs and is implicated in CKD progression. DNA demethylating drugs may interrupt the fetal programming of CKD by maternal obesity. Hydralazine, an antihypertensive agent, demethylates DNA at low doses which do not reduce blood pressure. We used a mouse model of maternal obesity to determine whether gestational administration of low-dose hydralazine to mothers can prevent CKD in offspring.

METHODS

C57BL/6 dams received HFD or chow from 6 weeks prior to mating and were administered subcutaneous hydralazine (5mg/kg) or saline thrice weekly during gestation. Male offspring were weaned to chow and were sacrificed at either postnatal week 9 or week 32. Biometric and metabolic parameters, renal global DNA methylation, renal structural and functional changes and markers of fibrosis, oxidative stress and inflammation were measured in offspring at weeks 9 and 32.

RESULTS

In week 9 offspring, maternal HFD consumption did not significantly alter anthropometric or metabolic parameters, or renal global DNA methylation. Week 32 offspring had increased renal global DNA methylation, together with albuminuria, glomerulosclerosis, renal fibrosis and oxidative stress. Administration of low-dose hydralazine to obese mothers during gestation reduced renal global DNA methylation and renal fibrotic markers in week 32 offspring.

CONCLUSION

Gestational hydralazine reduced renal global DNA methylation in offspring of obese mothers and attenuated maternal obesity-induced renal fibrosis. These data support the use of low-dose hydralazine as a demethylating agent to prevent CKD arising in offspring due to maternal HFD consumption.

Male Patients may be More Vulnerable to Acute Kidney Injury After Colorectal Surgery in an Enhanced Recovery Program: A Propensity Score Matching Analysis

BACKGROUND

Although many reports have shown that enhanced recovery after surgery (ERAS) programs improve the perioperative outcomes of patients undergoing colorectal surgery, the prevalence of early acute kidney injury (AKI) after surgery in such patients requires attention. Protective roles of the female sex in terms of chronic kidney disease and progression of ischemic renal injury have been described in many studies. We thus explored whether a sex difference was evident in terms of postoperative AKI in a colorectal ERAS setting.

METHODS

From January 2017 to August 2019, 453 patients underwent laparoscopic colorectal cancer resection in an enhanced recovery program. Of these, 217 female patients were propensity score (PS)-matched with 236 male patients. Then, 215 patients of either sex were compared in terms of postoperative renal function and complications.

RESULTS

Among the PS-matched patients, the incidence of AKI was significantly higher in male than female patients (24.2% vs. 9.8%, P < 0.001). Male patients also exhibited a greater reduction in the postoperative estimated glomerular filtration rate, compared with female patients. The male sex was associated with an approximately threefold increase in the risk of AKI. The rate of surgical complications was significantly higher in male than female patients.

CONCLUSIONS

Caution must be taken to prevent postoperative AKI in patients (particularly males) participating in colorectal ERAS programs. The mechanism underlying the sex difference remains unclear. Additional studies are required to determine whether male patients require perioperative management that differs from that of females, to prevent postoperative AKI.

Sex-specific Associations of Sex Hormone Binding Globulin with CKD and Kidney Function: A Univariable and Multivariable Mendelian Randomization Study in the UK Biobank

BACKGROUND

Kidney function declines faster in men. Testosterone levels may mediate the sex disparity. Correspondingly, levels of sex hormone binding globulin (SHBG), which modulates sex hormones, might also be relevant to the lower kidney function in men. The sex-specific role of SHBG is unclear.

METHODS

A sex-specific, Mendelian randomization (MR) study provided unconfounded estimates of SHBG levels among the United Kingdom Biobank population. Univariable MR applied 357 single nucleotide polymorphisms (SNPs) in men and 359 SNPs in women. These published SNPs strongly (P<5×10^-8) predict SHBG level. They were profiled in 179,916 white British men (6016 patients with CKD) and 212,079 white British women (5958 patients with CKD), to obtain the effect of SHBG on CKD, albuminuria, and eGFR. Multivariable MR controlling for testosterone was used to assess the effect of SHBG on CKD and kidney function independent of testosterone in men.

RESULTS

Genetically predicted higher SHBG was associated with a lower risk of CKD in men (odds ratio [OR], 0.78 per SD; 95% confidence interval [95% CI], 0.65 to 0.93) but had no benefit in women. The effect in men remained in multivariable MR, allowing for testosterone (OR, 0.61; 95% CI, 0.45 to 0.82).

CONCLUSIONS

Genetically predicted higher SHBG was associated with a lower risk of CKD and better kidney function in men, but not in women, suggesting that SHBG may play a role in CKD specifically in men. Identifying drivers of SHBG and the underlying pathways could provide new insights into CKD prevention and treatment.

Providing Care for Transgender Persons With Kidney Disease: A Narrative Review

Purpose of review

Nephrologists are increasingly providing care to transgender individuals with chronic kidney disease (CKD). However, they may lack familiarity with this patient population that faces unique challenges. The purpose of this review is to discuss the care of transgender persons and what nephrologists should be aware of when providing care to their transgender patients.

Sources of information

Original research articles were identified from MEDLINE and Google Scholar using the search terms "transgender," "gender," "sex," "chronic kidney disease," "end stage kidney disease," "dialysis," "transplant," and "nephrology."

Methods

A focused review and critical appraisal of existing literature regarding the provision of care to transgender men and women with CKD including dialysis and transplant to identify specific issues related to gender-affirming therapy and chronic disease management in transgender persons.

Key findings

Transgender persons are at an increased risk of adverse outcomes compared with the cisgender population including mental health, cardiovascular disease, malignancy, sexually transmitted infections, and mortality. Individuals with CKD have a degree of hypogonadotropic hypogonadism and decreased levels of endogenous sex hormones; therefore, transgender persons with CKD may require reduced exogenous sex hormone dosing. Exogenous estradiol therapy increases the risk of venous thromboembolism and cardiovascular disease which may be further increased in CKD. Exogenous testosterone therapy increases the risk of polycythemia which should be closely monitored. The impact of gender-affirming hormone therapy on glomerular filtration rate (GFR) trajectory in CKD is unclear. Gender-affirming hormone therapy with testosterone, estradiol, and anti-androgen therapies changes body composition and lean body mass which influences creatinine generation and the performance for estimated glomerular filtration rate (eGFR) equations in transgender persons. Confirmation of eGFR with measured GFR is reasonable if an accurate knowledge of GFR is needed for clinical decision-making.

Limitations

There are limited studies regarding the intersection of transgender persons and kidney disease and those that exist are mostly case reports. Randomized controlled trials and observational studies in nephrology do not routinely differentiate between cisgender and transgender participants.

Implications

This review highlights important considerations for providing care to transgender persons with kidney disease. Additional research is needed to evaluate the performance of eGFR equations in transgender persons, the effects of gender-affirming hormone therapy, and the impact of being transgender on outcomes in persons with kidney disease.

Matrix metalloproteinase-9 gene polymorphism (-1562 C/T) and its correlation with diabetic nephropathy

Background

Matrix metalloproteinase 9 (MMP-9) is an important inflammatory marker in diabetic nephropathy. Many studies assessed the association between MMP-9 gene polymorphism and different microvascular complications of type 2 diabetes mellitus, though the results were inconclusive and need further exploration. Our study aimed to assess the association between MMP-9 -1562C/T gene polymorphism and diabetic nephropathy in patients with type 2 diabetes mellitus.

Results

Taking CC genotype of rs3918242 (MMP-9-1562C/T SNP) as the reference genotype and C as the reference allele, TT genotype, T allele showed significantly lower frequency in diabetic nephropathy group than without nephropathy (2.9% versus 20%, 20% versus 35.7% respectively), with the possible significant protective effect against diabetic nephropathy development (OR = 0.269, 0.450 respectively); it was considered as an independent predictor for diabetic nephropathy occurrence.

Conclusions

This study suggested that T allele of MMP-9 -1562C/T single nucleotide polymorphism had a protective role against diabetic nephropathy development and also had a role for early prediction of patients susceptible to this complication, so it helps in prevention and management of those patients.

[Chronic kidney disease among adults in Rio Branco, State of Acre: a population-based survey]

The scope of this study was to establish the prevalence of CKD and associated factors among young adults (18-59 years of age) from Rio Branco in the State of Acre. It involved a population-based survey conducted in 2014, in the urban and rural areas of the municipality and CKD was defined as the glomerular filtration rate (GFR) < 60ml/min/1.73m², estimated by the CKD-EPI, and the presence of albuminuria > 29 mg/g. Association measures were estimated by logistic regression, with a confidence level of 95%. The overall prevalence of CKD was 6.2%. The presence of CKD was higher among women, aged 40 to 59 years, with non-white skin color, with lower schooling, and of sedentary disposition. There were statistically significant differences in the distribution according to the presence of CKD in the hypertension, diabetes and hospitalization variables over the past 12 months. CKD among adults was associated with the female sex (OR: 2.41, 95%CI: 1.14-5.12), diabetes (OR: 4.67, 95%CI: 1.28-17.03) and arterial hypertension (OR: 1.98; 95%CI: 1.16-3.37). CKD reveals a high prevalence and is associated with chronic diseases, calling for the need for public health measures for early detection and prevention of its progression.

Providing Care for Transgender Persons With Kidney Disease: A Narrative Review

Purpose of review:

Nephrologists are increasingly providing care to transgender individuals with chronic kidney disease (CKD). However, they may lack familiarity with this patient population that faces unique challenges. The purpose of this review is to discuss the care of transgender persons and what nephrologists should be aware of when providing care to their transgender patients.

Sources of information:

Original research articles were identified from MEDLINE and Google Scholar using the search terms “transgender,” “gender,” “sex,” “chronic kidney disease,” “end stage kidney disease,” “dialysis,” “transplant,” and “nephrology.”

Methods:

A focused review and critical appraisal of existing literature regarding the provision of care to transgender men and women with CKD including dialysis and transplant to identify specific issues related to gender-affirming therapy and chronic disease management in transgender persons.

Key findings:

Transgender persons are at an increased risk of adverse outcomes compared with the cisgender population including mental health, cardiovascular disease, malignancy, sexually transmitted infections, and mortality. Individuals with CKD have a degree of hypogonadotropic hypogonadism and decreased levels of endogenous sex hormones; therefore, transgender persons with CKD may require reduced exogenous sex hormone dosing. Exogenous estradiol therapy increases the risk of venous thromboembolism and cardiovascular disease which may be further increased in CKD. Exogenous testosterone therapy increases the risk of polycythemia which should be closely monitored. The impact of gender-affirming hormone therapy on glomerular filtration rate (GFR) trajectory in CKD is unclear. Gender-affirming hormone therapy with testosterone, estradiol, and anti-androgen therapies changes body composition and lean body mass which influences creatinine generation and the performance for estimated glomerular filtration rate (eGFR) equations in transgender persons. Confirmation of eGFR with measured GFR is reasonable if an accurate knowledge of GFR is needed for clinical decision-making.

Limitations:

There are limited studies regarding the intersection of transgender persons and kidney disease and those that exist are mostly case reports. Randomized controlled trials and observational studies in nephrology do not routinely differentiate between cisgender and transgender participants.

Implications:

This review highlights important considerations for providing care to transgender persons with kidney disease. Additional research is needed to evaluate the performance of eGFR equations in transgender persons, the effects of gender-affirming hormone therapy, and the impact of being transgender on outcomes in persons with kidney disease.