Extracellular sodium regulates fibroblast growth factor 23 (FGF23) formation.

The bone-derived hormone fibroblast growth factor-23 (FGF23) has recently received much attention due to its association with chronic kidney disease and cardiovascular disease progression. Extracellular sodium concentration ([Na+]) plays a significant role in bone metabolism. Hyponatremia (lower serum [Na+]) has recently been shown to be independently associated with FGF23 levels in patients with chronic systolic heart failure. However, nothing is known about the direct impact of [Na+] on FGF23 production. Here, we show that an elevated [Na+] (+20 mM) suppressed FGF23 formation, whereas low [Na+] (-20 mM) increased FGF23 synthesis in the osteoblast-like cell lines UMR-106 and MC3T3-E1. Similar bidirectional changes in FGF23 abundance were observed when osmolality was altered by mannitol but not by urea, suggesting a role of tonicity in FGF23 formation. Moreover, these changes in FGF23 were inversely proportional to the expression of NFAT5 (nuclear factor of activated T cells-5), a transcription factor responsible for tonicity-mediated cellular adaptations. Furthermore, arginine vasopressin, which is often responsible for hyponatremia, did not affect FGF23 production. Next, we performed a comprehensive and unbiased RNA-seq analysis of UMR-106 cells exposed to low versus high [Na+], which revealed several novel genes involved in cellular adaptation to altered tonicity. Additional analysis of cells with Crisp-Cas9-mediated NFAT5 deletion indicated that NFAT5 controls numerous genes associated with FGF23 synthesis, thereby confirming its role in [Na+]-mediated FGF23 regulation. In line with these in vitro observations, we found that hyponatremia patients have higher FGF23 levels. Our results suggest that [Na+] is a critical regulator of FGF23 synthesis.

Implications of Renal Disease in Patients Undergoing Structural Interventions.

Percutaneous structural interventions have a major impact on the morbidity, mortality, and quality of life of patients by providing a lower-risk alternative to cardiac surgery. However, renal disease has a significant impact on outcomes of these interventions. This review explores the incidence, outcomes, pathophysiology, and preventative measures of acute kidney injury and chronic kidney disease on transcatheter aortic valve replacement, transcatheter mitral valve repair, and percutaneous balloon mitral valvuloplasty. Given the expanding indications for percutaneous structural interventions, further research is needed to identify ideal patients with chronic kidney disease or end-stage renal disease who would benefit from intervention.

Incident vertebral fracture and longitudinal BMD change in Chinese postmenopausal women with early CKD: Peking Vertebral Fracture Study.

Early chronic kidney disease (CKD) and non-CKD individuals had similar morphometric vertebral fracture (mVF) incidence and longitudinal bone mineral density (BMD) change. CKD did not modify the association between BMD and incident mVF status. Patients with a higher baseline BMD had a higher longitudinal BMD loss in early CKD. PURPOSE: The aim of this 5-year longitudinal cohort study was to compare the risk of incident morphometric vertebral fracture (mVF) and longitudinal bone mineral density (BMD) change between individuals with early chronic kidney disease (CKD) and those without CKD. METHODS: A total of 869 Chinese postmenopausal women were enrolled in the study. Serum creatinine levels were assessed using standard methods, and estimated glomerular filtration rate (eGFR) was calculated using the Chronic Kidney Disease Epidemiology Collaboration equation. Incident mVF was confirmed through lateral radiographs of the thoracolumbar spine. BMDs at the lumbar spine (LS) and femoral neck (FN) were measured using dual-energy X-ray absorptiometry. CKD was defined based on eGFR values: 60-89 mL/min/1.73m2 for stage 2 (n = 511) and 30-59 mL/min/1.73m2 for stage 3 (n = 92). The non-CKD group included individuals with an eGFR greater than or equal to 90 mL/min/1.73m2. RESULTS: The incidence of mVF was not statistically different between individuals with early CKD and those without CKD (4.1% in non-CKD, 6.3% in CKD stage 2, and 7.6% in CKD stage 3; p = 0.348). Neither eGFR nor CKD status was significantly associated with incident mVF in the multivariate logistic regression analysis. Baseline BMD T-scores were negatively associated with incident mVF (LS T-score, OR = 0.603, 95% CI = 0.468-0.777; FN T-score, OR = 0.511, 95% CI = 0.350-0.746). No evidence of interaction between BMD T-scores and CKD status were identified (p = 0.284-0.785) . The differences in longitudinal BMD changes between non-CKD and CKD groups were comparable (FN BMD: -6.31 ± 7.20% in non-CKD, -5.07 ± 8.20% in CKD stage 2, and -4.49 ± 8.40% in CKD stage 3, p = 0.556; LS BMD: -1.38 ± 8.18% in non-CKD, -0.32 ± 7.14% in CKD stage 2, and 1.5 ± 6.97% in CKD stage 3, p = 0.406). Individuals with a higher baseline FN BMD showed a greater longitudinal FN BMD loss (r = -0.185, p < 0.001) . CONCLUSIONS: Our study revealed that early CKD was not associated with an increased risk of incident mVF or greater longitudinal BMD loss. Moreover, CKD did not modify the association between BMD and the risk of incident mVF, suggesting that the management and prevention of fractures in early CKD should be approached similarly to those without CKD. Measurement of BMD appears to be crucial for predicting incident mVF risk and longitudinal bone loss in early CKD.

Metabolic reprogramming heterogeneity in chronic kidney disease.

Fibrosis driven by excessive accumulation of extracellular matrix (ECM) is the hallmark of chronic kidney disease (CKD). Myofibroblasts, which are the cells responsible for ECM production, are activated by cross talk with injured proximal tubule and immune cells. Emerging evidence suggests that alterations in metabolism are not only a feature of but also play an influential role in the pathogenesis of renal fibrosis. The application of omics technologies to cell-tracing animal models and follow-up functional data suggest that cell-type-specific metabolic shifts have particular roles in the fibrogenic response. In this review, we cover the main metabolic reprogramming outcomes in renal fibrosis and provide a future perspective on the field of renal fibrometabolism.

Time to Abolish Metrics That Sustain Systemic Racism in Kidney Allocation.

This Viewpoint discusses how the Kidney Donor Profile Index (KDPI) in its current form is not fit to guide kidney allocation because it devalues organ donation by Black donors based on a weak association between donor race and kidney transplant failure.

Neck circumference and its association with anthropometric, clinical, and biochemical parameters in patients with chronic kidney disease on hemodialysis / Circunferência do pescoço e sua associação com parâmetros antropométricos, clínicos e bioquímicos em pacientes com doença renal crônica em hemodiálise

ABSTRACT Objective: To investigate the association between neck circumference and anthropometric, clinical, and biochemical parameters in chronic kidney failure patients on hemodialysis. Methods: This is a cross-sectional study with patients with chronic kidney disease undergoing hemodialysis in Western Bahia. For the data collection, anthropometric measures were taken and clinical and biochemical data were gathered from the patient records and employing a structured questionnaire. A multiple linear regression was applied to evaluate the relationship between neck circumference and the anthropometric, clinical, and biochemical parameters. Results: A total of 119 patients were evaluated, of which 63.03% were men and 57.98% were aged between 35 and 59 years old. The mean neck circumference of the patients was 36.2±3.8 cm. A negative association was found between neck circumference and the female sex (p<0.001), while waist circumference (p<0.001), the body adiposity index (p=0.002), and pre-dialysis serum urea concentration (p=0.006) were positively associated with neck circumference. Conclusion: Neck circumference is inversely associated with the female sex and positively associated with a high waist circumference, body adiposity index, and serum urea concentration in patients with chronic kidney disease on hemodialysis.

RESUMO Objetivo: Investigar a associação entre circunferência do pescoço e parâmetros antropométricos, clínicos e bioquímicos em pacientes renais crônico sem hemodiálise. Métodos: Trata-se de um estudo transversal com pacientes com doença renal crônica em hemodiálise no Oeste da Bahia. Para a coleta de dados foram aferidas medidas antropométricas e dados clínicos e bioquímicos foram coletados dos prontuários dos pacientes e por meio de um questionário estruturado. A análise de regressão linear múltipla foi aplicada para avaliar a relação entre a circunferência do pescoço e os parâmetros antropométricos, clínicos e bioquímicos. Resultados: Foram avaliados 119 pacientes, sendo 63,03% homens e 57,98% com idade entre 35 e 59 anos. A média da circunferência do pescoço dos pacientes foi de 36,2±3,8 cm. Foi encontrada associação negativa entre a circunferência do pescoço e sexo feminino (p<0,001), enquanto a circunferência da cintura (p<0,001), o índice de adiposidade corporal (p=0,002) e a concentração sérica de ureia pré-diálise (p=0,006) foram positivamente associados à circunferência do pescoço. Conclusão: A circunferência do pescoço está inversamente associada ao sexo feminino e positivamente associada a uma circunferência abdominal elevada, índice de adiposidade corporal e concentração sérica de ureia em pacientes com doença renal crônica em hemodiálise.

Finerenone and Heart Failure Outcomes by Kidney Function/Albuminuria in Chronic Kidney Disease and Diabetes.

BACKGROUND: In patients with type 2 diabetes (T2D), risks of cardiovascular mortality and heart failure (HF) increase with decreasing kidney function (estimated glomerular filtration rate [eGFR]) and increasing albuminuria (urine albumin-to-creatinine ratio [UACR]). Finerenone, a selective, nonsteroidal mineralocorticoid receptor antagonist, improved cardiorenal outcomes in patients with chronic kidney disease (CKD) and T2D in FIDELITY (Finerenone in Chronic Kidney Disease and Type 2 Diabetes: Combined FIDELIO-DKD and FIGARO-DKD Trial Programme Analysis). OBJECTIVES: This study sought to evaluate the effects of finerenone on HF outcomes by eGFR and/or UACR categories. METHODS: FIDELITY included 13,026 patients with T2D and CKD (UACR 30-5,000 mg/g and eGFR ≥25 mL/min/1.73 m2) randomized to finerenone or placebo. Time-to-event outcomes were first hospitalization for heart failure (HHF), cardiovascular death or first HHF, recurrent HHF, and cardiovascular death or recurrent HHF, analyzed in subgroups by baseline eGFR (<60 and ≥60 mL/min/1.73 m2) and/or UACR (<300 and ≥300 mg/g). RESULTS: Compared with placebo, finerenone significantly reduced risk of first HHF (HR: 0.78 [95% CI: 0.66-0.92]; P = 0.003), cardiovascular death or first HHF (HR: 0.83 [95% CI: 0.74-0.93]; P = 0.002), recurrent HHF (HR: 0.79 [95% CI: 0.64-0.96]; P = 0.021), and cardiovascular death or recurrent HHF (HR: 0.82 [95% CI: 0.72-0.95]; P = 0.006). The risk of outcomes increased across baseline eGFR and UACR categories; lowest incidences were seen in patients with an eGFR ≥60 mL/min/1.73 m2 and a UACR <300 mg/g. Finerenone improved HF outcomes irrespective of baseline eGFR and/or UACR categories (all P interaction values >0.10). CONCLUSIONS: Compared with placebo, finerenone improved HF-related outcomes in patients with CKD and T2D, with consistent benefits across eGFR and/or UACR categories. (Efficacy and Safety of Finerenone in Subjects With Type 2 Diabetes Mellitus and Diabetic Kidney Disease [FIDELIO-DKD], NCT02540993; Efficacy and Safety of Finerenone in Subjects With Type 2 Diabetes Mellitus and the Clinical Diagnosis of Chronic Kidney Disease [FIGARO-DKD], NCT02545049).

Monitoring Approaches for a Pediatric Chronic Kidney Disease Machine Learning Model.

OBJECTIVE: The purpose of this study is to evaluate the ability of three metrics to monitor for a reduction in performance of a chronic kidney disease (CKD) model deployed at a pediatric hospital. METHODS: The CKD risk model estimates a patient's risk of developing CKD 3 to 12 months following an inpatient admission. The model was developed on a retrospective dataset of 4,879 admissions from 2014 to 2018, then run silently on 1,270 admissions from April to October, 2019. Three metrics were used to monitor its performance during the silent phase: (1) standardized mean differences (SMDs); (2) performance of a "membership model"; and (3) response distribution analysis. Observed patient outcomes for the 1,270 admissions were used to calculate prospective model performance and the ability of the three metrics to detect performance changes. RESULTS: The deployed model had an area under the receiver-operator curve (AUROC) of 0.63 in the prospective evaluation, which was a significant decrease from an AUROC of 0.76 on retrospective data (p = 0.033). Among the three metrics, SMDs were significantly different for 66/75 (88%) of the model's input variables (p <0.05) between retrospective and deployment data. The membership model was able to discriminate between the two settings (AUROC = 0.71, p <0.0001) and the response distributions were significantly different (p <0.0001) for the two settings. CONCLUSION: This study suggests that the three metrics examined could provide early indication of performance deterioration in deployed models' performance.

First genome-wide association study investigating blood pressure and renal traits in domestic cats.

Hypertension (HTN) and chronic kidney disease (CKD) are common in ageing cats. In humans, blood pressure (BP) and renal function are complex heritable traits. We performed the first feline genome-wide association study (GWAS) of quantitative traits systolic BP and creatinine and binary outcomes HTN and CKD, testing 1022 domestic cats with a discovery, replication and meta-analysis design. No variants reached experimental significance level in the discovery stage for any phenotype. Follow up of the top 9 variants for creatinine and 5 for systolic BP, one SNP reached experimental-wide significance for association with creatinine in the combined meta-analysis (chrD1.10258177; P = 1.34 × 10-6). Exploratory genetic risk score (GRS) analyses were performed. Within the discovery sample, GRS of top SNPs from the BP and creatinine GWAS show strong association with HTN and CKD but did not validate in independent replication samples. A GRS including SNPs corresponding to human CKD genes was not significant in an independent subset of cats. Gene-set enrichment and pathway-based analysis (GSEA) was performed for both quantitative phenotypes, with 30 enriched pathways with creatinine. Our results support the utility of GWASs and GSEA for genetic discovery of complex traits in cats, with the caveat of our findings requiring validation.

Effects of oral alkali drug therapy on clinical outcomes in pre-dialysis chronic kidney disease patients: a systematic review and meta-analysis.

BACKGROUND: Metabolic acidosis accelerates the progression of chronic kidney disease (CKD) and increases the mortality rate. Whether oral alkali drug therapy benefits pre-dialysis CKD patients is controversial. We performed a meta-analysis of the effects of oral alkali drug therapy on major clinical outcomes in pre-dialysis CKD patients. METHODS: We systematically searched MEDLINE using the Ovid, EMBASE, and Cochrane Library databases without language restriction. We included all eligible clinical studies that involved pre-dialysis CKD adults and compared those who received oral alkali drug therapy with controls. RESULTS: A total of 18 eligible studies, including 14 randomized controlled trials and 4 cohort studies reported in 19 publications with 3695 participants, were included. Oral alkali drug therapy led to a 55% reduction in renal failure events (relative risk [RR]: 0.45; 95% confidence interval [CI]: 0.25-0.82), a rate of decline in the estimated glomerular filtration rate (eGFR) of 2.59 mL/min/1.73 m2 per year (95% CI, 0.88-4.31). There was no significant effect on decline in eGFR events (RR: 0.34; 95% CI: 0.09-1.23), proteinuria (standardized mean difference: -0.32; 95% CI: -1.08 to 0.43), all-cause mortality events (RR: 0.90; 95% CI: 0.40-2.02) and cardiovascular (CV) events (RR: 1.03; 95% CI: 0.32-3.37) compared with the control groups. CONCLUSION: Based on the available and low-to-moderate certainty evidence, oral alkali drug therapy might potentially reduce the risk of kidney failure events, but no benefit in reducing all-cause mortality events, CV events, decline in eGFR and porteninuria.

The influence of PM2.5 exposure on kidney diseases.

The harm of air pollution to public health has become a research hotspot, especially atmospheric fine-particulate matter (PM2.5). In recent years, epidemiological investigations have confirmed that PM2.5 is closely related to chronic kidney disease and membranous nephropathy Basic research has demonstrated that PM2.5 has an impact on the normal function of the kidneys through accumulation in the kidney, endothelial dysfunction, abnormal renin-angiotensin system, and immune complex deposition. Moreover, the mechanism of PM2.5 damage to the kidney involves inflammation, oxidative stress, apoptosis, DNA damage, and autophagy. In this review, we summarized the latest developments in the effects of PM2.5 on kidney disease in human and animal studies, so as to provide new ideas for the prevention and treatment of kidney disease.

Effects of veverimer on serum bicarbonate and physical function in women with chronic kidney disease and metabolic acidosis: a subgroup analysis from a randomised, controlled trial.

BACKGROUND: Globally, the prevalence of chronic kidney disease (CKD) is higher in women than in men; however, women have been historically under-represented in nephrology clinical trials. Metabolic acidosis increases risk of progressive loss of kidney function, causes bone demineralization and muscle protein catabolism, and may be more consequential in women given their lower bone and muscle mass. Veverimer, an investigational, non-absorbed polymer that binds and removes gastrointestinal hydrochloric acid, is being developed as treatment for metabolic acidosis. METHODS: This was a Phase 3, multicenter, randomised, blinded, placebo-controlled trial in 196 patients with CKD (eGFR: 20-40 mL/min/1.73 m2) and metabolic acidosis who were treated for up to 1 year with veverimer or placebo. We present the findings from a pre-specified subgroup analysis evaluating the effects of veverimer on metabolic acidosis and physical function among women (N = 77) enrolled in this trial. RESULTS: At week 52, women treated with veverimer had a greater increase in mean (± standard error) serum bicarbonate than the placebo group (5.4 [0.5] vs. 2.2 [0.6] mmol/L; P < 0.0001). Physical Function reported by patients on the Kidney Disease and Quality of Life - Physical Function Domain, a measure that includes items related to walking, stair climbing, carrying groceries and other activities improved significantly in women randomized to veverimer vs placebo (+ 13.2 vs. -5.2, respectively, P < 0.0031). Objectively measured performance time on the repeated chair stand test also improved significantly in the veverimer group vs. placebo (P = 0.0002). CONCLUSIONS: Veverimer was effective in treating metabolic acidosis in women with CKD, and significantly improved how they felt and functioned. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT03390842 . Registered on January 4, 2018.

Mitochondrial Pathophysiology on Chronic Kidney Disease.

In healthy kidneys, interstitial fibroblasts are responsible for the maintenance of renal architecture. Progressive interstitial fibrosis is thought to be a common pathway for chronic kidney diseases (CKD). Diabetes is one of the boosters of CKD. There is no effective treatment to improve kidney function in CKD patients. The kidney is a highly demanding organ, rich in redox reactions occurring in mitochondria, making it particularly vulnerable to oxidative stress (OS). A dysregulation in OS leads to an impairment of the Electron transport chain (ETC). Gene deficiencies in the ETC are closely related to the development of kidney disease, providing evidence that mitochondria integrity is a key player in the early detection of CKD. The development of novel CKD therapies is needed since current methods of treatment are ineffective. Antioxidant targeted therapies and metabolic approaches revealed promising results to delay the progression of some markers associated with kidney disease. Herein, we discuss the role and possible origin of fibroblasts and the possible potentiators of CKD. We will focus on the important features of mitochondria in renal cell function and discuss their role in kidney disease progression. We also discuss the potential of antioxidants and pharmacologic agents to delay kidney disease progression.