RICORS2040: the need for collaborative research in chronic kidney disease

Kidney function and cognitive impairment: a systematic review and meta-analysis

BACKGROUND

A worldwide evaluation exploring the link between a broad-spectrum kidney function and cognitive impairment (CI) prevalence, and related risk factors has yet to be conducted.

METHODS

Studies published before November 2024 were retrieved from PubMed and Web of Science. R software (R Foundation for Statistical Computing, Vienna, Austria) and Review Manager (Cochrane Collaboration, London, UK) were used to analyze the relationship of CI with various estimated glomerular filtration rate (eGFR) level and the associated risk factors. A random model effect was adopted for a heterogeneity (I2) of more than 50%.

RESULTS

Seventeen (involving 32,141 participants) out of 5892 studies were included. The MMSE and MoCA were the most commonly used tests to assess cognitive function. The prevalence of CI raised significantly with declining kidney function: 10% for eGFR ≥60 mL/min/1.73 m2, 47.3% for 60-30 mL/min/1.73 m2, and 60.6% for <30 mL/min/1.73 m2, totaling 16.7% overall. Thirteen potential risk factors were ascertained and analyzed. In the forest-plot analysis, T2DM, cardiovascular diseases, cerebrovascular diseases, and lower education emerged as strong predictors of risk, with odds ratios of 1.55, 1.63, 1.95, and 2.59, respectively. A mean meta-analysis of the continuous variable indicators revealed that advanced age and elevated parathyroid hormone (PTH) levels were statistically significant in the occurrence of CI.

CONCLUSIONS

The poorer the renal function, the higher the prevalence rate of CI. Patients with chronic kidney disease (CKD) have multiple risk factors that lead to CI.

Diosmin attenuates UUO-induced renal ferroptosis and fibrosis by inhibiting the HIF-1α/FABP4 signaling axis

BACKGROUND AND PURPOSE

Renal fibrosis is a major pathological feature of chronic kidney disease (CKD) that poses significant therapeutic challenges owing to its irreversible nature. In this study, we aimed to investigate the effects of diosmin, a polyphenolic flavonoid with anti-inflammatory, antioxidant, and antifibrotic properties, on renal fibrosis and to explore the underlying mechanisms.

STUDY DESIGN AND METHODS

Mouse renal fibrosis model induced by UUO surgery and an HK-2 cell fibrosis model stimulated by TGF-β1 were established to evaluate the effects of diosmin treatment on cell injury, inflammatory response, and ferroptosis. Changes in the expression of related genes in the kidney tissues were analyzed using RNA-seq. In addition, the effects of fatty acid-binding protein 4 (FABP4) on the efficacy of diosmin were explored by knockdown and overexpression of FABP4. Double luciferase reporter gene assay, Chip-qPCR, molecular docking, surface plasmon resonance, and cellular thermal shift experiments were performed to explore this mechanism.

RESULTS

Diosmin mitigated renal tubular injury and collagen deposition in the UUO model by modulating fibrotic markers, such as fibronectin, Col I α1, and α-SMA. It also reduces iron accumulation, decreases the expression of MDA, ASCL4, and inflammatory cytokines, and increases the expression of GPX4 and SOD2, thereby attenuating ferroptosis and enhancing the cellular response to oxidative stress. In vitro, diosmin counteracted TGF-β1-induced cellular damage and ferroptosis. RNA-seq analysis revealed that diosmin intervention suppressed the expression of FABP4 induced by UUO and targeted silencing of FABP4 attenuated cellular damage and ferroptosis. Conversely, FABP4 overexpression in vivo compromised the renoprotective effects of diosmin. Mechanically, diosmin was found to bind to HIF-1α and reduce its nuclear translocation, thereby inhibiting FABP4 transcription, resulting in reduced inflammation, collagen deposition, and ferroptosis. Furthermore, the overexpression of HIF-1α reversed the protective effects of diosmin.

CONCLUSION

Diosmin potentially attenuates renal ferroptosis and fibrosis through the inhibition of the HIF-1α/FABP4 axis, offering a promising therapeutic approach for renal fibrosis.

Impact of metabolic phenotype changes on the development of chronic kidney disease: Panasonic cohort study 17

OBJECTIVE

This study investigated how changes in metabolic phenotype, defined by obesity and metabolic health, impact chronic kidney disease (CKD) development in a large cohort.

METHODS

A retrospective cohort study analyzed health data collected between 2011 and 2021 from 84,729 Panasonic Holdings Corporation (formerly Panasonic Corporation) employees aged ≥40 years. Metabolic phenotypes were classified as metabolically healthy with no obesity (MHNO), metabolically healthy with obesity (MHO), metabolic abnormalities with no obesity (MANO), and metabolic abnormalities with obesity (MAO). Changes in metabolic phenotype over 3 years and their association with CKD development were assessed using Cox proportional hazards models adjusted for confounding variables.

RESULTS

During a mean follow-up of 5.1 years, a total of 12,172 of participants (14.4%) developed CKD. Transitioning from MHO to MHNO and from MAO to MANO did not reduce CKD risk compared to each stable group. In contrast, participants in the MANO-to-MHNO and MAO-to-MHO groups significantly lowered CKD risk relative to each stable group, with hazard ratios of 0.86 (95% CI: 0.77-0.96) and 0.83 (95% CI: 0.67-1.02), respectively. The same results were observed when a rapid decline in renal function was used as the outcome.

CONCLUSIONS

The improvement of metabolic profile might outweigh weight reduction in CKD risk.

Spanish Registry of Renal Patients: 2022 Report and evolutive analysis

INTRODUCTION

Chronic kidney disease (CKD) will be the second leading cause of death in Spain by 2100. The Spanish Renal Disease Registry (REER) records the incidence, prevalence and mortality of all patients requiring renal replacement therapy (RRT) in Spain.

METHODS

Data are provided by Spanish autonomous regions and cities and the Organización Nacional de Trasplantes. Incidence and prevalence rates of RRT have been calculated (considering the Spanish population according to annual data from the Instituto Nacional de Estadística), as well as mortality of patients on RRT in our country during the period 2013-2022.

RESULTS

The incidence rate of RRT increased by 21% from 2013 to 2019, and stabilized thereafter, with a value of 152.2 cases per million population (pmp) in 2022, of which 77.8% were on haemodialysis (HD), 16.7% on peritoneal dialysis (PD) and 5.5% received a preemptive kidney transplant. Diabetes was the leading cause of CKD requiring RRT (21.8%), followed by other causes (21.6%). The incidence rate of RRT was 2-fold higher in men than in women, with large regional differences (1.93-fold for men and 2.55-fold for women in regions with the highest and lowest incidence rates). The prevalence rate of RRT was 1,391.1 pmp in 2022, showing a progressive increase over the last decade, mainly at the expense of an increase in the transplant population (765.0 pmp, 55.0%). In 2022, 3,404 kidney transplants were performed in Spain (71.7 pmp), which situates it as a world leader. The most frequent donor type was the donor after the neurological determination of death (51.5%), followed by the donor after the circulatory determination of death (37%). The overall annual mortality of RRT patients was 8.4% (13.8% for HD, 10.1% for PD and 3.9% for transplantation).

CONCLUSIONS

Although it has stabilized somewhat in recent years, the incidence and prevalence of RRT continues to rise in Spain. Additional measures must be adopted to harmonize and optimize kidney health care.

Nanomaterials for targeted therapy of kidney diseases: Strategies and advances

The treatment and management of kidney diseases pose a significant global burden. Due to the presence of blood circulation barriers and glomerular filtration barriers, drug therapy for kidney diseases faces challenges such as poor renal targeting, short half-life, and severe systemic side effects, severely hindering therapeutic progress. Therefore, the research and development of kidney-targeted therapeutic agents is of great clinical significance. In recent years, the application of nanotechnology in the field of nephrology has shown potential for revolutionizing the diagnosis and treatment of kidney diseases. Carefully designed nanomaterials can exhibit optimal biological characteristics, influencing various aspects such as circulation, retention, targeting, and excretion. Rationally designing and modifying nanomaterials based on the anatomical structure and pathophysiological environment of the kidney to achieve highly specific kidney-targeted nanomaterials or nanodrug delivery systems is both feasible and promising. Based on the targeted therapy of kidney diseases, this review discusses the advantages and limitations of current nanomedicine in the targeted therapy of kidney diseases, and summarizes the application and challenges of current renal active/passive targeting strategies, in order to further promote the development of kidney-targeted nanomedicine through a preliminary summary of previous studies and future prospects.

Ziltivekimab for anemia and atherosclerosis in chronic kidney disease: a new hope?

Anemia of chronic kidney disease is a multifactorial condition secondary to various etiologies, including nutritional deficiencies, chronic inflammation, erythropoietin deficiency or resistance, bone marrow suppression, iron deficiency and adverse drug effects. The major therapeutic intervention for anemia among chronic kidney disease patients is erythropoiesis-stimulating agents. However, a limitation of erythropoiesis-stimulating agents is the risk for thromboembolic events, hypertension, seizures, solid organ malignancies and hyporesponsiveness. A novel interleukin-6 monoclonal antibody, ziltivekimab, has been evaluated for managing anemia in chronic kidney disease patients in pilot clinical trials with promising outcomes, including an improvement in hemoglobin levels and reduction of inflammatory parameters. These trials have shown that ziltivekimab does not increase the risk for cytopenia or infectious complications as has been described for other interleukin-6-targeting monoclonal antibodies, like tocilizumab. Furthermore, potentially beneficial effects on serum lipid profile have been reported, leading to the hypothesis of a favorable impact of the drug on atherosclerotic complications. In addition, ziltivekimab has shown efficacy in improving anemia parameters, including hemoglobin levels and iron studies. Ziltivekimab deserves full scale clinical development, and to this aim, large-scale clinical trials are under way.

Cefadroxil Targeting of SLC15A2/PEPT2 Protects From Colistin Nephrotoxicity

Acute kidney injury (AKI) and chronic kidney disease (CKD) are considered interconnected syndromes, as AKI episodes may accelerate CKD progression, and CKD increases the risk of AKI. Genome-wide association studies (GWAS) may identify novel actionable therapeutic targets. Human GWAS for AKI or CKD were combined with murine AKI transcriptomics data sets to identify 13 (ACACB, ACSM5, CNDP1, DPEP1, GATM, SLC6A12, AGXT2L1, SLC15A2, CTSS, ICAM1, ITGAX, ITGAM, and PPM1J) potentially actionable therapeutic targets to modulate kidney disease severity across species and the AKI-CKD spectrum. Among them, SLC15A2, encoding the cell membrane proton-coupled peptide transporter 2, was prioritized for data mining and functional intervention studies in vitro and in vivo because of its known function to transport nephrotoxic drugs such as colistin and the possibility for targeting with small molecules already in clinical use, such as cefadroxil. Data mining disclosed that SLC15A2 was upregulated in the tubulointerstitium of human CKD, including diabetic nephropathy, and the upregulation was localized to proximal tubular cells. Colistin elicited cytotoxicity and proinflammatory response in cultured human and murine proximal tubular cells that was decreased by concomitant exposure to cefadroxil. In proof-of-concept in vivo studies, cefadroxil protected from colistin nephrotoxicity in mice. The GWAS association of SLC15A2 with human kidney disease may be actionable and related to the modifiable transport of nephrotoxins causing repeated subclinical episodes of AKI and/or chronic nephrotoxicity.

Improving the sustainability and quality of kidney health care through life cycle assessments, quality improvement, education and technical innovations: the KitNewCare approach

The European Union (EU)-funded KitNewCare consortium aims to create and manage a comprehensive EU-wide programme focusing on sustainability in Kidney Care. Around 850 million people have chronic kidney disease (CKD) worldwide and by 2030, 6 million will need kidney replacement therapy, mainly haemodialysis. As the world population gets older, projections for the end of the century worsen. From a sustainability perspective, healthcare systems contribute around 5-11% of total carbon emissions. Kidney care is one of the most resource-intensive specialties. In addition to energy, haemodialysis and peritoneal dialysis require transportation of patients and personnel to and from facilities, use large volumes of water and generate significant plastic waste. Overall, current dialysis is not sustainable in the medium term. Primary prevention, early diagnosis and treatment of CKD and transplantation will decrease the need for dialysis, but this will take time and will not prevent the need for dialysis in millions of persons. There is a need to improve knowledge around the environmental and financial cost of kidney care and social and health outcomes of each patient pathway including using holistic tools such as life cycle assessment. This knowledge will allow workflow optimisations, organisational transformations and technological innovations across Europe, learning from different clinical sites. KitNewCare will build a European-wide knowledge base for sustainability in kidney care, develop and introduce a novel 4-factor database for comprehensive impact analysis, implement optimised processes and organisational transformations in four European clinical sites. It will also pilot innovations from small- and medium-sized high-tech enterprises with a focus on kidney care, and establish a network for continuous monitoring, benchmarking, and implementation of sustainable solutions across healthcare sectors. This paper presents the rationale behind selecting kidney disease as a focal point, summarises the current state of knowledge, and outlines the foundational statement underlying KitNewCare's operational framework.

Propionate and butyrate counteract renal damage and progression to chronic kidney disease

BACKGROUND

Short-chain fatty acids (SCFAs), mainly acetate, propionate and butyrate, are produced by gut microbiota through fermentation of complex carbohydrates that cannot be digested by the human host. They affect gut health and can contribute at the distal level to the pathophysiology of several diseases, including renal pathologies.

METHODS

SCFA levels were measured in chronic kidney disease (CKD) patients (n = 54) at different stages of the disease, and associations with renal function and inflammation parameters were examined. The impact of propionate and butyrate in pathways triggered in tubular cells under inflammatory conditions was analysed using genome-wide expression assays. Finally, a pre-clinical mouse model of folic acid-induced transition from acute kidney injury to CKD was used to analyse the preventive and therapeutic potential of these microbial metabolites in the development of CKD.

RESULTS

Faecal levels of propionate and butyrate in CKD patients gradually reduce as the disease progresses, and do so in close association with established clinical parameters for serum creatinine, blood urea nitrogen and the estimated glomerular filtration rate. Propionate and butyrate jointly downregulated the expression of 103 genes related to inflammatory processes and immune system activation triggered by tumour necrosis factor-α in tubular cells. In vivo, the administration of propionate and butyrate, either before or soon after injury, respectively, prevented and slowed the progression of damage. This was indicated by a decrease in renal injury markers, the expression of pro-inflammatory and pro-fibrotic markers, and recovery of renal function over the long term.

CONCLUSIONS

Propionate and butyrate levels are associated with a progressive loss of renal function in CKD patients. Early administration of these SCFAs prevents disease advancement in a pre-clinical model of acute renal damage, demonstrating their therapeutic potential independently of the gut microbiota.

Oxidative balance score is associated with the risk of diabetic kidney disease in patients with type 2 diabetes mellitus: evidence from NHANES 2007-2018

Objective

The oxidative balance score (OBS) is a comprehensive measure of oxidative stress that is calculated from the combined prooxidant and antioxidant scores of 16 dietary components and four lifestyle factors. This study aimed to evaluate the relationship between OBS and the risk of diabetic kidney disease (DKD) in individuals with Type 2 diabetes mellitus (T2DM).

Methods

Data were obtained from the NHANES. A cross-sectional study was conducted using multiple logistic regression. Covariate effects of this relationship were also examined using subgroup analysis.

Results

We evaluated 3,669 T2DM participants, among whom DKD prevalence was 30.87%. In a fully adjusted logistic regression model, the risk of DKD among participants with OBS, lifestyle OBS, and dietary OBS in the highest quartile group was 0.50 times (95% CI: 0.39 to 0.65), 0.54 times (95% CI: 0.41-0.71), and 0.45 times (95% CI: 0.32-0.63), respectively, than that in the lowest quartile group, respectively. In addition, participants who scored in the top quartiles of OBS were more likely to possess higher levels of education and income. A stratified analysis demonstrated the robustness of these findings.

Conclusion

OBS negatively correlates with the risk of DKD among individuals with T2DM.

Jian-Pi-Yi-Shen formula ameliorates renal fibrosis-induced anemia in rats with chronic kidney disease

ETHNOPHARMACOLOGICAL RELEVANCE

Jian-Pi-Yi-Shen (JPYS) formula is an effective herbal therapy against renal injury, and JPYS has been clinically applied to ameliorate chronic kidney disease (CKD) and CKD-associated anemia. Increasing evidence supports the link between renal fibrosis and anemia in CKD. JPYS possessed anti-fibrosis effects in experimental CKD. Nevertheless, research on the mechanisms of JPYS in ameliorating renal anemia (RA) through suppressing renal fibrosis remains to be clarified.

AIM OF THE STUDY

Our study here was carried out to investigate the mechanisms of JPYS in protecting against RA.

MATERIALS AND METHODS

An adenine-induced anemia model in rats with CKD at three different time points was established, and bio-samples taken from each group were analyzed. Biochemical analysis was employed to detect kidney function and hematological parameters. Masson staining was used to evaluate renal fibrosis of rats. Western blot and immunohistochemistry were utilized to evaluate the expressions of fibrotic markers, erythropoietin (EPO) and hypoxia inducible factor-2α (HIF-2α) in the kidneys of rats. Subsequently, transcriptomic analysis was conducted to disclose the possible mechanisms of JPYS in treating RA. Finally, the expression levels of key targets were analyzed and validated by using Western blot and enzyme-linked immunosorbent assay (ELISA).

RESULTS

JPYS treatment improved kidney function, suppressed renal fibrosis and enhanced hematological parameters in CKD rats. Moreover, JPYS treatment restored the increased expression levels of fibrotic markers and the declined EPO with time dependence. In parallel, data indicated JPYS treatment stimulated the translocation of HIF-2α into nucleus in the renal interstitium and thus promoted the expression of EPO. Transcriptomic profiling disclosed that activations of both nuclear factor kappa B (NF-κB) and transforming growth factor-β (TGF-β)/Smad pathways were closely associated with RA. Ultimately, experimental validation results presented that the increased expressions of target proteins from the above-mentioned two pathways in the kidneys were decreased significantly after JPYS treatment.

CONCLUSION

Our findings suggest that JPYS may improve RA by alleviating renal fibrosis, and the mechanisms of which involve in inhibiting the NF-κB and TGF-β/Smad pathways.

GLP-1 receptor agonists in patients with chronic kidney disease and either overweight or obesity

Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) have emerged as game-changers across the cardiovascular-kidney-metabolic (CKM) spectrum: overweight/obesity, type 2 diabetes mellitus (T2DM) and associated chronic kidney disease (CKD) and cardiovascular disease (CVD). Liraglutide, semaglutide and tirzepatide are European Medicines Agency approved to improve metabolic control in T2DM and to decrease weight in persons with obesity [body mass index (BMI) ≥30 kg/m2] or with overweight (BMI ≥27 kg/m2) associated with weight-related comorbidities such as hypertension, dyslipidaemia, CVD and others. Additionally, liraglutide and semaglutide are approved to reduce CVD risk in patients with CVD and T2DM. Semaglutide is also approved to reduce CVD risk in patients with CVD and either obesity or overweight and in phase 3 clinical trials showed kidney and cardiovascular protection in patients with T2DM and albuminuric CKD (FLOW trial) as well as in persons without diabetes that had CVD and overweight/obesity (SELECT trial). Thus, nephrologists should consider prescribing GLP-1 RAs to improve metabolic control, reduce CVD risk or improve kidney outcomes in three scenarios: patients with overweight and a related comorbid condition such as hypertension, dyslipidaemia or CVD, patients with obesity and patients with T2DM. This review addresses the promising landscape of GLP-1 RAs to treat persons with overweight or obesity, with or without T2DM, within the context of CKD, assessing their safety and impact on weight, metabolic control, blood pressure and kidney and cardiovascular outcomes, as part of a holistic patient-centred approach to preserve CKM health.

Genetic Characterization of Kidney Failure of Unknown Etiology in Spain: Findings From the GENSEN Study

RATIONALE & OBJECTIVE

Chronic kidney disease of unknown etiology (CKDUE) is one of the main global causes of kidney failure. Genetic studies may identify an etiology in these patients, but few studies have implemented genetic testing of CKDUE in a population-based series of patients, which was the focus of the GENSEN Study.

STUDY DESIGN

Case series.

SETTINGS & PARTICIPANTS

818 patients aged≤45 years at 51 Spanish centers with CKDUE, and either an estimated glomerular filtration rate of<15mL/min/1.73m2 or treatment with maintenance dialysis or transplantation.

OBSERVATIONS

Genetic testing for 529 genes associated with inherited nephropathies using high-throughput sequencing (HTS). Pathogenic and/or likely pathogenic (P/LP) gene variants concordant with the inheritance pattern were detected in 203 patients (24.8%). Variants in type IV collagen genes were the most frequent (COL4A5, COL4A4, COL4A3; 35% of total gene variants), followed by NPHP1, PAX2, UMOD, MUC1, and INF2 (7.3%, 5.9%, 2.5%, 2.5%, and 2.5%, respectively). Overall, 87 novel variants classified as P/LP were identified. The top 5 most common previously undiagnosed diseases were Alport syndrome spectrum (35% of total positive reports), genetic podocytopathies (19%), nephronophthisis (11%), autosomal dominant tubulointerstitial kidney disease (7%), and congenital anomalies of the kidney and urinary tract (CAKUT, 5%). A family history of kidney disease was reported by 191 participants (23.3%) and by 65 of 203 patients (32.0%) with P/LP variants.

LIMITATIONS

Missing data, and selection bias resulting from voluntary enrollment.

CONCLUSIONS

Genomic testing with HTS identified a genetic cause of kidney disease in approximately one quarter of young patients with CKDUE and advanced kidney disease. These findings suggest that genetic studies are a potentially useful tool for the evaluation of people with CKDUE.

PLAIN-LANGUAGE SUMMARY

The cause of kidney disease is unknown for 1 in 5 patients requiring kidney replacement therapy, reflecting possible prior missed treatment opportunities. We assessed the diagnostic utility of genetic testing in children and adults aged≤45 years with either an estimated glomerular filtration rate of<15mL/min/1.73m2 or treatment with maintenance dialysis or transplantation. Genetic testing identified the cause of kidney disease in approximately 1 in 4 patients without a previously known cause of kidney disease, suggesting that genetic studies are a potentially useful tool for the evaluation of these patients.

Systemic immunoinflammatory indexes in albuminuric adults are negatively associated with α-klotho: evidence from NHANES 2007-2016

BACKGROUND

Systemic Immune-Inflammation Index (SII) is a novel inflammatory biomarker closely associated with the inflammatory response and chronic kidney disease. Klotho is implicated as a pathogenic factor in the progression of kidney disease, and supplementation of Klotho may delay the progression of chronic kidney disease by inhibiting the inflammatory response. Our aim is to investigate the potential relationship between SII and Klotho in adult patients in the United States and explore the differences in the populations with and without albuminuria.

METHODS

We conducted a cross-sectional study recruiting adult participants with complete data on SII, Klotho, and urine albumin-to-creatinine ratio (ACR) from the National Health and Nutrition Examination Survey from 2007 to 2016. SII was calculated as platelet count × neutrophil count/lymphocyte count, with abnormal elevation defined as values exceeding 330 × 10^9/L. Albuminuria was defined as ACR >30 mg/g. Weighted multivariable regression analysis and subgroup analysis were employed to explore the independent relationship between SII and Klotho.

RESULTS

Our study included a total of 10,592 individuals. In all populations, non-albuminuria population, and proteinuria population with ACR ≥ 30, participants with abnormally elevated SII levels, as compared to those with SII less than 330 × 10^9/L, showed a negative correlation between elevated SII levels and increased Klotho, which persisted after adjusting for covariates.

CONCLUSIONS

There is a negative correlation between SII and Klotho in adult patients in the United States. This finding complements previous research but requires further analysis through large prospective studies.

Association between renal function trajectories and risk of cardiovascular disease: a prospective cohort study

INTRODUCTION

It is unclear whether changing trajectories of renal function will increase the risk prediction information of cardiovascular disease (CVD). This study aimed to evaluate the trajectory patterns of estimated glomerular filtration rate (eGFR) and the association between eGFR trajectories and CVD risk.

METHODS

A total of 4742 participants were included in the cohort from the 51st Regiment of Xinjiang Production and Construction Corps. The study endpoint was the occurrence of CVD events. eGFR trajectories were identified using a linear mixed-effects model in four distinct patterns. Multivariate Cox proportional hazards models analysed the correlations between eGFR trajectories and CVD.

RESULTS

During a median follow-up period of 5.7 years, a total of 559 (11.8%) CVD, 404 (8.5%) myocardial infarction (MI), 244 (5.2%) ischemic stroke (IS), and 62 (1.3%) heart failure (HF) incidents occurred. After multivariable adjustment, gradual decline trajectory increased the risk of CVD (HR 1.42, 95% CI 1.16-1.74), MI (HR 1.41, 95% CI 1.11-1.79), and IS (HR 1.41, 95% CI 1.04-1.92); gradual increase trajectory reduced the risk of CVD (HR 0.40, 95% CI 0.25-0.64) and MI (HR 0.49, 95% CI 0.29-0.81). Consistent results were obtained in sensitivity and subgroup analyses.

CONCLUSIONS

Decline and increase of renal function were related to the risk of CVD, MI, and IS in the rural areas of Xinjiang. Monitoring eGFR changing trajectory is of great significance in improving the risk of CVD.

Ultrasound viscoelastic imaging in the noninvasive quantitative assessment of chronic kidney disease

BACKGROUND

This study aims to evaluate the clinical application value of ultrasound viscoelastic imaging in noninvasive quantitative assessment of chronic kidney disease (CKD).

METHODS

A total of 332 patients with CKD and 190 healthy adults as a control group were prospectively enrolled. Before kidney biopsy, ultrasound viscoelastic imaging was performed to measure the mean stiffness value (Emean), mean viscosity coefficient (Vmean), and mean dispersion coefficient (Dmean) of the renal. CKD patients were divided into three groups based on estimated glomerular filtration rate. The differences in clinic, pathology, ultrasound image parameters between the control and patient groups, or among different CKD groups were compared. The correlation between viscoelastic parameters and pathology were analyzed.

RESULTS

Emean, Vmean, and Dmean in the control group were less than the CKD group (p < 0.05). In the identification of CKD from control groups, the area under curve of Vmean, Dmean, Emean, and combining the three parameters is 0.90, 0.79, 0.69, 0.91, respectively. Dmean and Vmean were increased with the decline of renal function (p < 0.05). Vmean and Dmean were positively correlated with white blood cell, urea, serum creatinine, and uric acid (p < 0.05). Vmean is positively correlated with interstitial fibrosis and inflammatory cell infiltration grades (p < 0.001).

CONCLUSIONS

Ultrasound viscoelastic imaging has advantages in noninvasive quantitative identification and evaluating renal function of CKD. Emean > 6.61 kPa, Vmean > 1.86 Pa·s, or Dmean > 7.51 m/s/kHz may suggest renal dysfunction. Combining Vmean, Dmean, and Emean can improve the efficiency of identifying CKD.

Global trends and prospects related to macrophage in chronic kidney disease: a bibliometric analysis

BACKGROUND AND AIMS

Macrophages play a variety of widely concerned roles in the process of chronic kidney disease (CKD). To further understand the research hotspots and development trends regarding the relationship between macrophages and CKD, the role of macrophages in the occurrence and progression of CKD was summarized by bibliometrics in this study.

MATERIAL AND METHODS

We collected the studies relevant the role of macrophages in CKD from the Web of Science Core Collection, which included 1332 relevant studies from Jan 1st, 2004 to Jul 6th, 2023 in WoSCC. CiteSpace, biblioshiny in R, VOSviewer and SCImago Graphica Beta were used for bibliometric analysis and visualization.

RESULTS

Monash University from Australia is the most productive institution, while China and the USA are most productive countries. Anders HJ is the most cited author. In terms of the number of co-citations, the top one was "Macrophages: versatile players in renal inflammation and fibrosis" by Patrick Ming-Kuen Tang, published in Nature Reviews Nephrology in 2019. Important keywords of this research topic include inflammation, dendritic cell, oxidative stress, NF-κB, tgf-beta, interstitial fibrosis, glomerulonephritis, diabetic nephropathy. Future research hotspots may include molecular mechanism, acute kidney injury, macrophage polarization, kidney fibrosis.

CONCLUSION

This study provides a systematic review of the role of macrophages in CKD and speculates that future research hotspots. Previous studies have focused on the immune function of macrophages and atypia, and metabolic factors (especially iron metabolism within macrophages) have attracted the attention of researchers in recent years and are the forefront of recent research.

Projection of the clinical and economic burden of chronic kidney disease between 2022 and 2027 in Spain: Results of the Inside CKD project

BACKGROUND AND OBJECTIVE

Chronic kidney disease (CKD) is a growing health problem affecting between 10% and 15% of the Spanish population. The lack of updated projections of the evolution of the disease burden hinders the development of evidence-based health policies and interventions to optimise the management of the disease and prevent its progression. The aim of this study is to project the evolution of the clinical and economic burden of CKD in Spain between 2022 and 2027.

MATERIALS AND METHODS

Inside CKD uses a validated microsimulation approach to project the burden of CKD. The projection is based on a virtual population according to Spanish demographics, literature, national data registries and clinical expert opinion. Costs associated with CKD management, renal replacement therapy (RRT), cardiovascular complications and arterial comorbidities were included.

RESULTS

In Spain, an absolute increase in the prevalence of CKD of 1% (from 10.7% to 11.7%) is expected between 2022 and 2027, corresponding to an increase from 5.14 million to 5.68 million patients in 2027. However, only one third of CKD patients would be diagnosed. Of these diagnosed patients, 3.9% will require RRT in 2027, an increase of 14.7% from 2022. A total of 654,281 accumulated deaths are expected in patients with CKD diagnosed between 2022 and 2027. The economic burden of diagnosed CKD is expected to increase by 13.8% to 4.89 billion euros in 2027, representing 5.56% of total Spanish public health expenditure in 2027 (compared to 4.88% in 2022), of which 42.5% will be allocated to RRT (2.4% of public health expenditure).

CONCLUSIONS

The Inside CKD project highlights the growing clinical, economic and social burden of CKD in Spain expected by 2027. Progression to more advanced stages with the need for RRT and associated complications represent a small proportion of the total CKD population, but contribute significantly to overall costs.

The biology of ferroptosis in kidney disease

Ferroptosis is a regulated cell death modality triggered by iron-dependent lipid peroxidation. Ferroptosis plays a causal role in the pathophysiology of various diseases, making it a promising therapeutic target. Unlike all other cell death modalities dependent on distinct signaling cues, ferroptosis occurs when cellular antioxidative defense mechanisms fail to suppress the oxidative destruction of cellular membranes, eventually leading to cell membrane rupture. Physiologically, only two such surveillance systems are known to efficiently prevent the lipid peroxidation chain reaction by reducing (phospho)lipid hydroperoxides to their corresponding alcohols or by reducing radicals in phospholipid bilayers, thus maintaining the integrity of lipid membranes. Mechanistically, these two systems are linked to the reducing capacity of glutathione peroxidase 4 (GPX4) by consuming glutathione (GSH) on one hand and ferroptosis suppressor protein 1 (FSP1, formerly AIFM2) on the other. Notably, the importance of ferroptosis suppression in physiological contexts has been linked to a particular vulnerability of renal tissue. In fact, early work has shown that mice genetically lacking Gpx4 rapidly succumb to acute renal failure with pathohistological features of acute tubular necrosis. Promising research attempting to implicate ferroptosis in various renal disease entities, particularly those with proximal tubular involvement, has generated a wealth of knowledge with widespread potential for clinical translation. Here, we provide a brief overview of the involvement of ferroptosis in nephrology. Our goal is to introduce this expanding field for clinically versed nephrologists in the hope of spurring future efforts to prevent ferroptosis in the pathophysiological processes of the kidney.

Portable Electrochemical System and Platform with Point-of-Care Determination of Urine Albumin-to-Creatinine Ratio to Evaluate Chronic Kidney Disease and Cardiorenal Syndrome

The urine albumin (Alb)-to-creatinine (Crn) ratio (UACR) is a sensitive and early indicator of chronic kidney disease (CKD) and cardiorenal syndrome. This study developed a portable and wireless electrochemical-sensing platform for the sensitive and accurate determination of UACR. The developed platform consists of a carbon nanotube (CNT)-2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid)(ABTS)-based modified UACR sensor, a miniaturised potentiostat, a cup holder embedded with a magnetic stirrer and a smartphone app. The UACR sensing electrode is composed of two screen-printed carbon working electrodes, one screen-printed carbon counter electrode and a screen-printed AgCl reference electrode. The miniaturised potentiostat, which is controlled by the developed app, performs cyclic voltammetry and amperometry to detect Alb and Crn, respectively. Clinical trials of the proposed system by using spot urine samples from 30 diabetic patients indicate that it can accurately classify all three CKD risk statuses within 30 min. The high accuracy of our proposed sensing system exhibits satisfactory agreement with the commercial biochemical analyser TBA-25FR (Y = 0.999X, R2 = 0.995). The proposed UACR sensing system offers a convenient, reliable and affordable solution for personal mobile health monitoring and point-of-care urinalysis.

Urinary extracellular vesicles as a monitoring tool for renal damage in patients not meeting criteria for chronic kidney disease

Background

Current definition of chronic kidney disease (CKD) identifies only advanced stages, but effective management demands early detection. Urinary albumin-to-creatinine ratio (ACR) 30 mg/g is a cut-off point for CKD clinical diagnosis. Patients with lower values (normoalbuminuria) and eGFR > 60 mL/min/1.73 m2 are considered at no increased cardiorenal risk. However, higher incidence of renal function decline and cardiovascular events have been shown within the normoalbuminuria range. Novel subclinical indicators may help to identify higher-risk patients. Urinary extracellular vesicles (uEVs) are sentinels of renal function non-invasively. Here we aimed to approach the early assessment of cardiorenal risk by investigating the protein cargo of uEVs.

Methods

Hypertensive patients were classified in control group (C) with ACR < 10 mg/g, and high-normal group (HN) with ACR 10-30 mg/g. Isolated uEVs were characterized by western blotting and electron microscopy and the protein cargo was analyzed by untargeted proteomics (LC-MS/MS) in a first discovery cohort. Protein confirmation was performed in a different cohort by ExoView. Immunohistochemistry of human kidney biopsies was also performed to evaluate the potential of uEVs to reflect renal damage.

Results

HN albuminuria does not affect the uEVs concentration, size, or tetraspanin profile. Among >6200 uEVs proteins identified, 43 define a panel significantly altered in HN patients without variation in urine, mostly annotated in the tubule (39 out of 43). The tubular transporter long-chain fatty acid transport protein 2 (SLC27A2) and the apical membrane protein amnionless (AMN) confirmed their alteration in HN patients evidencing impaired tubular reabsorption. SLC27A2 showed tubular expression and significantly reduced levels in patients with diagnostic criteria for CKD.

Conclusions

Alterations in the EV-mediated molecular profile are evident before pathological ACR levels are reached. Direct quantitation of SLC27A2 and AMN in uEVs helps identifying normoalbuminuric subjects with higher cardiorenal risk in early monitoring of CKD.

Systems Biology and Novel Biomarkers for the Early Detection of Diabetic Kidney Disease

Diabetic kidney disease is the most common driver of chronic kidney disease (CKD)-associated mortality and kidney replacement therapy. Despite recent therapeutic advances (sodium glucose co-transporter 2 [SGLT2] inhibitors, finerenone), the residual kidney and mortality risk remains high for patients already diagnosed of having CKD (i.e., estimated glomerular filtration rate <60 mL/min/1.73 m2 or urinary albumin:creatinine ratio >30 mg/g). The challenge for the near future is to identify patients at higher risk of developing CKD to initiate therapy before CKD develops (primary prevention of CKD) and to identify patients with CKD and high risk of progression or death, in order to intensify therapy. We now discuss recent advances in biomarkers that may contribute to the identification of such high-risk individuals for clinical trials of novel primary prevention or treatment approaches for CKD. The most advanced biomarker from a clinical development point of view is the urinary peptidomics classifier CKD273, that integrates prognostic information from 273 urinary peptides and identifies high-risk individuals before CKD develops.

Genetic study in young patients with chronic kidney disease stage G5 from unknown etiology. The GENSEN study design

INTRODUCTION

Chronic kidney disease (CKD) of non-inherited etiology is one of the main causes of renal replacement therapy in our setting. Previous studies in other territories suggest that hereditary diseases could be one of the potential causes of this pathology, especially in younger patients. The GENSEN study will evaluate the presence of pathogenic genetic variants in subjects who have developed CKD category G5 before the age of 46 years, of non-inherited etiology.

METHODS

Observational, prospective, multicenter study, which evaluates the diagnostic utility of massive high-throughput sequencing (HTS) directed to a set of genes, in the identification of the cause of CKD. Patients from all over Spain will be included, from whom a blood or saliva sample will be taken and a panel of 529 genes associated with hereditary kidney disease will be analyzed. This publication communicates the study protocol.

CONCLUSION

The GENSEN study will make it possible to evaluate the diagnostic performance of the gene panel study in young subjects in our setting with the development of CKD category G5 without a clear cause. An etiological diagnosis would offer potential benefits for patients and relatives (targeted therapies, clinical trials, detection of extrarenal manifestations, evaluation of relatives for live donation, estimation of the risk of recurrence in the renal graft, genetic counseling, among others) and would allow to apply this genetic study to the nephrology of our country.

Prevalence of cognitive impairment and its predictors among chronic kidney disease patients: A systematic review and meta-analysis

BACKGROUND

Cognitive impairment (CI) is common among patients with chronic kidney disease (CKD), and is associated with a poor prognosis. We assessed the prevalence and associated factors of CI in patients with CKD.

METHODS

A systematic review and meta-analysis were conducted by searching PubMed, Embase, and the Web of Science through December 1, 2023. Random effects models were performed with subgroup analyses to further explore the heterogeneity.

RESULTS

50 studies involving 25,289 CKD patients were included. The overall prevalence of CI was 40% (95% confidence interval 33-46). The pooled prevalence of CI was relatively higher in CKD patients from Africa (58%), Asia (44%) and America (37%). Attention and executive dysfunction appeared to be the most common manifestations. The prevalence of CI was higher among patients with hemodialysis (53%) and peritoneal dialysis (39%) than those without dialysis (32%) and post-kidney transplanted (26%). In addition, advanced age, the presence of diabetes and hypertension might increase the risk of CI in CKD patients.

CONCLUSIONS

People with CKD have a high prevalence of CI, especially in patients with hemodialysis. An early and comprehensive screening for CI in CKD patients is needed to improve clinical outcomes.

TRIAL REGISTRATION

Registration number: PROSPERO (CRD42023412864).

[Association Between the Aggregate Index of Systemic Inflammation and Albuminuria: A Cross-Sectional Study of National Health and Nutrition Examination Survey 2007-2018]

Objective

Prior studies have established a connection between albuminuria and various inflammatory reactions, highlighting that an increase in C-reactive protein by 1 mg/L increases the likelihood of albuminuria by 2%. Recent investigations indicate a positive correlation between the systemic immune-inflammation index (SII) and increased urinary protein excretion. In addition, elevated levels of the systemic inflammatory response index (SIRI) also correlate with a higher prevalence of albuminuria. The aggregate index of systemic inflammation (AISI) offers a more comprehensive indicator of inflammation, providing an extensive assessment of systemic inflammatory status compared to SII and SIRI. Yet, the specific relationship between AISI and albuminuria remains unclear. This study aims to explore this association in U.S. adults.

Methods

We analyzed data from the National Health and Nutrition Examination Survey (NHANES) for 2007-2018, excluding pregnant women and individuals under 18. Cases with missing data on AISI, urinary albumin concentration, and other covariates were also excluded. AISI was computed using the formula: AISI=(platelet count×neutrophil count×monocyte count)/lymphocyte count. Albuminuria was defined as the urinary albumin-to-creatinine ratio exceeding 30 mg/g. Continuous variables were presented in the form of the mean±standard error, and categorical variables in percentages. We utilized weighted t-tests and chi-square tests for baseline comparisons. We applied weighted multivariable logistic regression and generalized additive models (GAM) to explore the association between AISI and albuminuria and to assess potential nonlinear relationships.

Results

The study included 32273 participants, with an average age of (46.75±0.24) years old. The cohort comprised 48.73% males and 51.27% females. The prevalence of albuminuria was 9.64%. The average logarithmic value of log2AISI was 7.95±0.01, and were categorized into tertiles as follows: Quartile 1 (Q1) (4.94 to 7.49), Q2 (7.49 to 8.29), and Q3 (8.29 to 10.85). As log2AISI increased, so did the prevalence of hypertension, diabetes, congestive heart failure, and albuminuria, all showing statistically significant increases (P<0.001). Similarly, the use of antihypertensive, lipid-lowering, and hypoglycemic drugs was also more prevalent (P<0.001). Statistically significant differences were observed across the three groups concerning age, race and ethnicity, formal education, alcohol consumption, smoking status, systolic and diastolic blood pressures, body mass index, estimated glomerular filtration rate, HbA1c, alanine aminotransferase, aspartate aminotransferase, albumin, creatinine, uric acid, and high-density lipoprotein cholesterol (P<0.05). However, no significant differences were noted in the total cholesterol or the sex ratios among the groups. The association between log2AISI and albuminuria was assessed using weighted multivariable logistic regression, and the detailed results are presented in Table 2. In model 1, without adjusting for covariates, each unit increase in log2AISI was associated with a 32% increase in the risk of albuminuria (odds ratio [OR]=1.32, 95% confidence interval [CI]: 1.27-1.38, P<0.001). Model 2 was adjusted for age, gender, race, and education level, and showed a similar trend, with each unit increase in log2AISI associated with a 31% increased risk (OR=1.31, 95% CI: 1.26-1.37, P<0.001). Model 3, which was further adjusted for all covariates, revealed that each unit increase in log2AISI was associated with a 20% increase in the risk of albuminuria (OR=1.20, 95% CI: 1.15-1.26, P<0.001). The study also transformed log2AISI from a continuous to a categorical variable for analysis. Compared with Q1, the risk of albuminuria in Q3, after adjusting for all covariates, significantly increased (OR=1.37, 95% CI: 1.22-1.55, P<0.001). Q2 also demonstrated a higher risk compared with Q1 (OR=1.13, 95% CI: 1.06-1.36, P=0.004). The trend test indicated a dose-effect relationship between increasing log2AISI and the rising risk of albuminuria. GAM revealed a nonlinear relationship between log2AISI and albuminuria, with distinct trends noted between sexes. Segmented regression based on turning points showed significant effects among women, although the slope difference between the segments was not significant. In men, a significant threshold effect was observed; below the log2AISI of 7.25, increases in log2AISI did not enhance the risk of albuminuria, but above this threshold, the risk significantly increased. As part of a sensitivity analysis, weighted multivariable logistic regression was performed by changing the outcome variable to macroalbuminuria and adjusting for all covariates. The analysis showed that for every unit increase in log2AISI, the risk of developing macroalbuminuria increased by 31% (OR=1.31, 95% CI: 1.15-1.49, P<0.001). Compared with Q1, the risk of albuminuria in Q3 increased by 69% (OR=1.69, 95% CI: 1.27-2.25, P<0.001), and in Q2, it increased by 40% (OR=1.40, 95% CI: 1.03-1.92, P=0.030). Subgroup analysis and interaction results showed that the positive association between AISI and proteinuria risk was stronger in men than in women. Similarly, the association was stronger in people with hypertension compared with those with normal blood pressure, and higher in overweight people compared with those of normal weight. Furthermore, smokers and drinkers showed a stronger positive association between AISI and the risk of proteinuria than non-smokers and non-drinkers do. These results suggest that sex, blood pressure, body mass index, smoking, and alcohol consumption interact with AISI to influence the risk of proteinuria.

Conclusion

There is a robust positive association between AISI and increased risks of albuminuria in US adults. As log2AISI increases, so does the risk of albuminuria. However, further validation of this conclusion through large-scale prospective studies is warranted.

Association between oxidative balance score in adults with and without chronic kidney disease: 2011-2028 NHANES

Introduction

Oxidative stress status is associated with CKD; however, few studies have investigated this association. The oxidative balance score (OBS) reflects systemic stress status and consists of 16 anti-and pro-oxidant dietary factors and four anti-and pro-oxidant lifestyle factors. Higher OBS implies exposure to more antioxidants. The purpose of this study was to explore the association between OBS and CKD.

Methods

We enrolled 8,134 study participants from the 2011-2018 National Health and Nutrition Examination Survey and obtained OBS by adding the 20 dietary and lifestyle factors. Based on OBS, the participants were divided into three groups. We performed logistic regression, subgroup analyzes, and restricted cubic spline regression to explore the association between OBS and CKD. In addition, we tested the adjusted model.

Results

OBS was negatively associated with CKD (OR: 0.54; 0.66, 0.82). After adjusting for all confounders, when dietary OBS was >20, the prevalence of CKD was reduced by 42% for each unit increase in OBS (p < 0.05). The negative associations of total OBS, dietary OBS, and lifestyle OBS with CKD were more significant in the female group. When the total OBS was ~20, the trend of decreasing prevalence in the female group was more significant.

Conclusion

OBS is negatively associated with chronic kidney disease.

Regulation of regulated cell death by extracellular vesicles in acute kidney injury and chronic kidney disease

The imbalance between proliferation and death of kidney resident cells is a crucial factor in the development of acute or chronic renal dysfunction. Acute kidney injury (AKI) is often associated with the rapid loss of tubular epithelial cells (TECs). Sustained injury leads to the loss of glomerular endothelial cells (GECs) and podocytes, which is a key mechanism in the pathogenesis of glomerular diseases. This irreversible damage resulting from progressive cell loss eventually leads to deterioration of renal function characterized by glomerular compensatory hypertrophy, tubular degeneration, and renal fibrosis. Regulated cell death (RCD), which involves a cascade of gene expression events with tight structures, plays a certain role in regulating kidney health by determining the fate of kidney resident cells. Under pathological conditions, cells in the nephron have been demonstrated to constitutively release extracellular vesicles (EVs) which act as messengers that specifically interact with recipient cells to regulate their cell death process. For therapeutic intervention, exogenous EVs have exhibited great potential for the prevention and treatment of kidney disease by modulating RCD, with enhanced effects through engineering modification. Based on the functional role of EVs, this review comprehensively explores the regulation of RCD by EVs in AKI and chronic kidney disease (CKD), with emphasis on pathogenesis and therapeutic intervention.

Effect of uric acid reduction on chronic kidney disease. Systematic review and meta-analysis

Accumulating evidence suggests that hyperuricemia is a pathological factor in the development and progression of chronic kidney disease. However, the potential benefit afforded by the control of uric acid (UA) is controversial. Individual studies show discrepant results, and most existing meta-analysis, especially those including the larger number of studies, lack a placebo or control group as they aim to compare efficacy between drugs. On these grounds, we performed a me-ta-analysis restricted to studies including the action of any anti-gout therapies referenced to a control or placebo arm. This approach allows for a clearer association between UA reduction and renal effect. Of the twenty-nine papers included, most used allopurinol and febuxostat and, therefore, solid conclusions could only be obtained for these drugs. Both were very effective in reducing UA, but only allopurinol was able to significantly improve glomerular filtration rate (GFR), although not in a dose-dependent manner. These results raised doubts as to whether it is the hypouricemic effect of anti-gout drugs, or a pleiotropic effect, what provides protection of kidney function. Accordingly, in a correlation study that we next performed between UA reduction and GFR improvement, no association was found, which suggests that additional mechanisms may be involved. Of note, most trials show large inter-individual response variability, probably because they included patients with heterogeneous phenotypes and pathological characteristics, including different stages of CKD and comorbidities. This highlights the need to sub classify the effect of UA-lowering therapies according to the pathological scenario, in order to identify those CKD patients that may benefit most from them. Systematic Review Registration: CRD42022306646 https://www.crd.york.ac.uk/prospero/.

Increased serum methylmalonic acid levels were associated with the presence of cognitive dysfunction in older chronic kidney disease patients with albuminuria

BACKGROUND

This study aimed to evaluate the correlation between serum methylmalonic acid (MMA) levels and cognition function in patients with chronic kidney disease (CKD).

METHODS

In this cross-sectional study, we included 537 CKD individuals aged ≥ 60-year-old with albuminuria from the National Health and Nutrition Examination Survey (NHANES) 2011-2014. Four cognitive tests including the Digit Symbol Substitution Test (DSST), the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) Delayed Recall and Word Learning tests, and the Animal Fluency test (AF) were performed. Associations between MMA and cognition scores were assessed with linear regression models.

RESULTS

MMA level was negatively associated with residual renal function and nutrition status. After multivariate adjustment, elevated serum MMA levels were independently correlated with decline of cognition in CKD patients with albuminuria.

CONCLUSION

Our study showed that higher serum MMA levels were independently associated with the presence of cognition dysfunction in CKD patients. The exact pathogenesis of MMA and cognition needs further research.

Should we enlarge the indication for kidney biopsy in diabetics? The con part

Diabetes is the most common cause of chronic kidney disease (CKD), a condition found in 850 million persons and projected to become the fifth global cause of death by 2040. Research is needed that examines kidney tissue to characterize distinct phenotypes in patients with diabetes mellitus (DM) and CKD so as to identify non-invasive biomarker signatures and develop targeted therapeutic approaches. However, from a routine care point of view, kidney biopsy is likely overused in patients with CKD and DM, as most biopsy results are not expected to be associated with a therapeutic approach that differs from standard kidney protection with triple or quadruple therapy (renin-angiotensin system blockade, sodium-glucose cotransporter 2 inhibitors, nonsteroidal mineralocorticoid receptor antagonists and glucagon-like peptide-1 receptor agonists). Moreover, expanding the kidney biopsy criteria will increase the absolute number of complications from kidney biopsies, which may reach 27 000 to 108 000 deaths of persons that would derive little benefit from kidney biopsy if all people with DM and severe CKD were biopsied globally. Finally, limited resources should be optimally allocated. The cost of one kidney biopsy can fund 7000 semiquantitative urinary albumin:creatinine ratio assessments that could identify earlier stages of the disease and allow treatment that prevents progression to a stage at which kidney biopsy may be considered.

Urine MMP7 as a kidney injury biomarker

Matrix metalloproteinase 7 (MMP-7) is a secreted endopeptidase involved in the degradation of extracellular matrix components and the activation of cytokines and growth factors. The regulation of MMP-7 can be transcriptionally regulated by AP-1 or Wnt/β-catenin or post-translationally by proteolytic activation. MMP-7 expression is low or absent in the healthy kidney, but is significantly upregulated in kidney injury, including AKI and CKD. The function of MMP-7 in kidney disease may differ for CKD and AKI; it may have a profibrotic role in CKD and an anti-apoptotic and regenerative function in AKI. Additionally, the potential of MMP-7 as a biomarker has been studied in different kidney diseases, and the results are promising. Recently, combined unbiased kidney proteomics and transcriptomics approaches identified kidney MMP-7 as the protein having the strongest association with both fibrosis and eGFR and confirmed the predictive role of plasma MMP-7 levels for kidney function decline in over 11 000 individuals. Additionally, urinary MMP-7, combined with urinary cystatin C (CysC) and retinol binding protein (RBP) was reported to provide information on tubular injury in focal segmental glomerulosclerosis and minimal change disease. We now present an overview of research on MMP-7 expression and function in kidney diseases and discuss its potential as a biomarker of kidney diseases.

Overview of the safety, efficiency, and potential mechanisms of finerenone for diabetic kidney diseases

Diabetic kidney disease (DKD) is a common disorder with numerous severe clinical implications. Due to a high level of fibrosis and inflammation that contributes to renal and cardiovascular disease (CVD), existing treatments have not effectively mitigated residual risk for patients with DKD. Excess activation of mineralocorticoid receptors (MRs) plays a significant role in the progression of renal and CVD, mostly by stimulating fibrosis and inflammation. However, the application of traditional steroidal MR antagonists (MRAs) to DKD has been limited by adverse events. Finerenone (FIN), a third-generation non-steroidal selective MRA, has revealed anti-fibrotic and anti-inflammatory effects in pre-clinical studies. Current clinical trials, such as FIDELIO-DKD and FIGARO-DKD and their combined analysis FIDELITY, have elucidated that FIN reduces the kidney and CV composite outcomes and risk of hyperkalemia compared to traditional steroidal MRAs in patients with DKD. As a result, FIN should be regarded as one of the mainstays of treatment for patients with DKD. In this review, the safety, efficiency, and potential mechanisms of FIN treatment on the renal system in patients with DKD is reviewed.

Cardiorenal benefits of finerenone: protecting kidney and heart

Persons with diabetes and chronic kidney disease (CKD) have a high residual risk of developing cardiovascular (CV) complications despite treatment with renin-angiotensin system blockers and sodium-glucose cotransporter type 2 inhibitors. Overactivation of mineralocorticoid receptors plays a key role in the progression of renal and CV disease, mainly by promoting inflammation and fibrosis. Finerenone is a nonsteroidal selective mineralocorticoid antagonist. Recent clinical trials, such as FIDELIO-DKD and FIGARO-DKD and the combined analysis FIDELITY have demonstrated that finerenone decreases albuminuria, risk of CKD progression, and CV risk in subjects with type 2 diabetes (T2D) and CKD. As a result, finerenone should thus be considered as part of a holistic approach to kidney and CV risk in persons with T2D and CKD. In this narrative review, the impact of finerenone treatment on the CV system in persons with type 2 diabetes and CKD is analyzed from a practical point of view.Key messages:Despite inhibition of renin-angiotensin system and sodium-glucose cotransporter type 2, persons with type 2 diabetes (T2D) and chronic kidney disease (CKD) remain on high cardiovascular (CV) residual risk.Overactivation of mineralocorticoid receptors plays a key role in the progression of renal and CV disease, mainly by promoting inflammation and fibrosis that is not targeted by traditional treatments.Finerenone is a nonsteroidal selective mineralocorticoid antagonist that decreases not only albuminuria, but also the risk of CKD progression, and CV risk in subjects with T2D and CKD.

BET Protein Inhibitor JQ1 Ameliorates Experimental Peritoneal Damage by Inhibition of Inflammation and Oxidative Stress

Peritoneal dialysis (PD) is a current replacement therapy for end-stage kidney diseases (ESKDs). However, long-term exposure to PD fluids may lead to damage of the peritoneal membrane (PM) through mechanisms involving the activation of the inflammatory response and mesothelial-to-mesenchymal transition (MMT), leading to filtration failure. Peritoneal damage depends on a complex interaction among external stimuli, intrinsic properties of the PM, and subsequent activities of the local innate-adaptive immune system. Epigenetic drugs targeting bromodomain and extra-terminal domain (BET) proteins have shown beneficial effects on different experimental preclinical diseases, mainly by inhibiting proliferative and inflammatory responses. However the effect of BET inhibition on peritoneal damage has not been studied. To this aim, we have evaluated the effects of treatment with the BET inhibitor JQ1 in a mouse model of peritoneal damage induced by chlorhexidine gluconate (CHX). We found that JQ1 ameliorated the CHX-induced PM thickness and inflammatory cell infiltration. Moreover, JQ1 decreased gene overexpression of proinflammatory and profibrotic markers, together with an inhibition of the nuclear factor-κB (NF-κB) pathway. Additionally, JQ1 blocked the activation of nuclear factor erythroid 2-related factor 2 (NRF2) and restored changes in the mRNA expression levels of NADPH oxidases (NOX1 and NOX4) and NRF2/target antioxidant response genes. To corroborate the in vivo findings, we evaluated the effects of the BET inhibitor JQ1 on PD patients' effluent-derived primary mesothelial cells and on the MeT-5A cell line. JQ1 inhibited tumor necrosis factor-α (TNF-α)-induced proinflammatory gene upregulation and restored MMT phenotype changes, together with the downmodulation of oxidative stress. Taken together, these results suggest that BET inhibitors may be a potential therapeutic option to ameliorate peritoneal damage.

Lessons from SENCOVAC: A prospective study evaluating the response to SARS-CoV-2 vaccination in the CKD spectrum

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has negatively impacted on patients of the whole CKD spectrum, causing high rates of morbi-mortality. SARS-CoV-2 vaccines opened a new era, but patients with CKD (including kidney transplant, hemodialysis and peritoneal dialysis) were systematically excluded from pivotal clinical trials. The Spanish Society of Nephrology promoted the multicentric national SENCOVAC study aimed at assessing immunological responses after vaccination in patients with CKD. During the first year after vaccination, patients with non-dialysis CKD and those on hemodialysis and peritoneal dialysis presented good anti-Spike antibody responses to vaccination, especially after receiving the third and fourth doses. However, kidney transplant recipients presented suboptimal responses after any vaccination schedule (initial, third and fourth dose). Especially worrisome is the situation of a patients with a persistently negative humoral response that do not seroconvert after boosters. In this regard, monoclonal antibodies targeting SARS-CoV-2 have been approved for high-risk patients, although they may become obsolete as the viral genome evolves. The present report reviews the current status of SARS-CoV-2 vaccination in the CKD spectrum with emphasis on lessons learned from the SENCOVAC study. Predictors of humoral response, including vaccination schedules and types of vaccines, as well as the integration of vaccines, monoclonal antibodies and antiviral agents are discussed.

Mineralocorticoid receptor antagonist use in chronic kidney disease with type 2 diabetes: a clinical practice document by the European Renal Best Practice (ERBP) board of the European Renal Association (ERA)

Chronic kidney disease (CKD) in individuals with type 2 diabetes (T2D) represents a major public health issue; it develops in about 30%-40% of patients with diabetes mellitus and is the most common cause of CKD worldwide. Patients with CKD and T2D are at high risk of both developing kidney failure and of cardiovascular events. Renin-angiotensin system (RAS) blockers were considered the cornerstone of treatment of albuminuric CKD in T2D for more than 20 years. However, the residual risk of progression to more advanced CKD stages under RAS blockade remains high, while in major studies with these agents in patients with CKD and T2D no significant reductions in cardiovascular events and mortality were evident. Steroidal mineralocorticoid receptor antagonists (MRAs) are known to reduce albuminuria in individuals on RAS monotherapy, but their wide clinical use has been curtailed by the significant risk of hyperkalemia and absence of trials with hard renal outcomes. In recent years, non-steroidal MRAs have received increasing interest due to their better pharmacologic profile. Finerenone, the first compound of this class, was shown to effectively reduce the progression of kidney disease and of cardiovascular outcomes in participants with T2D in phase 3 trials. This clinical practice document prepared from a task force of the European Renal Best Practice board summarizes current knowledge on the role of MRAs in the treatment of CKD in T2D aiming to support clinicians in decision-making and everyday management of patients with this condition.

Prognostic Significance of Amino Acid and Biogenic Amines Profiling in Chronic Kidney Disease

There is a pressing need for more precise biomarkers of chronic kidney disease (CKD). Plasma samples from 820 subjects [231 with CKD, 325 with end-stage kidney disease (ESKD) and 264 controls] were analyzed by liquid chromatography with tandem mass spectrometry (LC-MS/MS) to determine a metabolic profile of 28 amino acids (AAs) and biogenic amines to test their value as markers of CKD risk and progression. The kynurenine/tryptophan ratio showed the strongest correlation with estimated glomerular filtration rate values (coefficient = -0.731, p < 0.0001). Models created with orthogonal partial least squares-discriminant analysis (OPLS-DA) containing the metabolic signature showed a high goodness of fit and predictability for controls/CKD (R2X:0.73:R2Y:0.92:Q2:0.92, p < 0.0001) and lower values for CKD/ESKD (R2X:0.56:R2Y:0.59:Q2:0.55, p < 0.0001). Based on generated VIP scores, the most relevant markers for segregating samples into control/CKD and CKD/ESKD groups were citrulline (1.63) and tryptophan (1.47), respectively. ROC analysis showed that the addition of the metabolic profile to a model including CKD classic risk factors improved the AUC from 86.7% (83.6-89.9) to 100% (100-100) for CKD risk (p < 0.0001) and from 63.0% (58.2-67.8) to 96.5% (95.3-97.8) for the risk of progression from CKD to ESKD (p < 0.0001). Plasma concentrations of AAs and related amines may be useful as diagnostic biomarkers of kidney disease, both for CKD risk and for progression of CKD patients to ESKD.

Bariatric Surgery Outcomes in Patients with Chronic Kidney Disease

Obesity increases the risk of developing chronic kidney disease (CKD), which has a major negative impact on global health. Bariatric surgery (BS) has demonstrated a substantial improvement of obesity-related comorbidities and thus, it has emerged as a potential therapeutic tool in order to prevent end-stage renal disease. A limited number of publications to date have examined the beneficial effects and risks of BS in patients with non-advanced stages of CKD. We aimed to investigate the safety of BS in patients with CKD stages 3-4 (directly related or not to obesity) and both the metabolic/renal outcomes post-BS. A total of 57 individuals were included (n = 19 for CKD-group; n = 38 for patients with obesity, but normal eGFR [control-group]). Weight loss and obesity comorbidities resolution after BS were similar in both groups. Renal function (eGFR [CKD-EPI]) improved significantly at the 1-year follow-up: Δ10.2 (5.2-14.9) (p < 0.001) for CKD-group and Δ4.0 (-3.9-9.0) mL/min/1.73 m2 (p = 0.043) for controls. Although this improvement tended to decrease in the 5-year follow-up, eGFR remained above its basal value for the CKD-group. Noteworthy, eGFR also improved in those patients who presented CKD not directly attributed to obesity. For patients with CKD, BS appears to be safe and effective regarding weight loss and obesity comorbidities resolution, irrespective of the main cause of CKD (related or not to obesity).

EMPA-KIDNEY: expanding the range of kidney protection by SGLT2 inhibitors

In the EMPA-KIDNEY (The Study of Heart and Kidney Protection With Empagliflozin) trial, empagliflozin reduced cardiorenal outcomes by 28% (hazard ratio 0.72; 95% confidence interval 0.64-0.82; P < .0001) in a diverse population of over 6000 chronic kidney disease (CKD) patients, of whom >50% were not diabetic. It expanded the spectrum of CKD that may benefit from sodium-glucose cotransporter 2 (SGLT2) inhibition to participants with urinary albumin: creatinine ratio <30 mg/g and estimated glomerular filtration rate (eGFR) >20 mL/min/1.73 m² or even lower (254 participants had an eGFR 15-20 mL/min/1.73 m²). EMPA-KIDNEY was stopped prematurely because of efficacy, thus limiting the ability to confirm benefit on the primary outcome in every pre-specified subgroup, especially in those with more slowly progressive CKD. However, data on chronic eGFR slopes were consistent with benefit at any eGFR or urinary albumin:creatinine ratio level potentially delaying kidney replacement therapy by 2-27 years, depending on baseline eGFR. The representation of diverse causes of CKD (>1600 participants with glomerular disease, >1400 with hypertensive kidney disease, >450 with tubulointerstitial disease and >600 with unknown cause) was higher than in prior SGLT2 inhibitor trials, although polycystic kidney disease was excluded. Around 15% (almost 1000) of participants were not on renin-angiotensin system blockade. The clinical characteristics of the cohort differed from DAPA-CKD (A Study to Evaluate the Effect of Dapagliflozin on Renal Outcomes and Cardiovascular Mortality in Patients With Chronic Kidney Disease), as did the frequency of individual components of the primary outcome in the placebo arm. Thus, rather than compare EMPA-KIDNEY with DAPA-CKD, the results of both trials should be seen as complementary to those of other SGLT2 inhibitor trials. Overall, EMPA-KIDNEY, a recent meta-analysis and post hoc analyses of participants with type 2 diabetes mellitus (T2DM) but no baseline CKD in other trials, indicates that SGLT2 inhibitor treatment will benefit an expanded CKD population with diverse baseline albuminuria or eGFR values, presence of T2DM or cause of CKD, as well as providing primary prevention of CKD in at least the T2DM setting.

CCN2 Activates RIPK3, NLRP3 Inflammasome, and NRF2/Oxidative Pathways Linked to Kidney Inflammation

Inflammation is a key characteristic of both acute and chronic kidney diseases. Preclinical data suggest the involvement of the NLRP3/Inflammasome, receptor-interacting protein kinase-3 (RIPK3), and NRF2/oxidative pathways in the regulation of kidney inflammation. Cellular communication network factor 2 (CCN2, also called CTGF in the past) is an established fibrotic biomarker and a well-known mediator of kidney damage. CCN2 was shown to be involved in kidney damage through the regulation of proinflammatory and profibrotic responses. However, to date, the potential role of the NLRP3/RIPK3/NRF2 pathways in CCN2 actions has not been evaluated. In experimental acute kidney injury induced with folic acid in mice, CCN2 deficiency diminished renal inflammatory cell infiltration (monocytes/macrophages and T lymphocytes) as well as the upregulation of proinflammatory genes and the activation of NLRP3/Inflammasome-related components and specific cytokine products, such as IL-1β. Moreover, the NRF2/oxidative pathway was deregulated. Systemic administration of CCN2 to C57BL/6 mice induced kidney immune cell infiltration and activated the NLRP3 pathway. RIPK3 deficiency diminished the CCN2-induced renal upregulation of proinflammatory mediators and prevented NLRP3 modulation. These data suggest that CCN2 plays a fundamental role in sterile inflammation and acute kidney injury by modulating the RIKP3/NLRP3/NRF2 inflammatory pathways.

Finerenone: towards a holistic therapeutic approach to patients with diabetic kidney disease

Despite current treatments, which include renin angiotensin system blockers and SGLT2 inhibitors, the risk of progression of kidney disease among patients with diabetes and chronic kidney disease (CKD) remains unacceptably high. The pathogenesis of CKD in patients with diabetes is complex and includes hemodynamic and metabolic factors, as well as inflammation and fibrosis. Finerenone is a highly selective nonsteroidal mineralocorticoid antagonist that, in contrast to current therapies, may directly reduce inflammation and fibrosis, thus adding value in the management of these patients. In fact, finerenone decreases albuminuria and slows CKD progression in persons with diabetes. We now review the mechanisms of action of finerenone, the results of recent clinical trials, and the integration of the kidney and cardiovascular protection afforded by finerenone in the routine care of patients with diabetes and CKD.

Optimization of potassium management in patients with chronic kidney disease and type 2 diabetes on finerenone

INTRODUCTION

Patients with type 2 diabetes (T2DM) and chronic kidney disease (CKD) are at high risk of CKD progression and cardiovascular events. Despite treatment with renin-angiotensin system inhibitors and SGLT-2 inhibitors, the residual risk is substantial. There is preclinical and clinical evidence supporting a key role of mineralocorticoid receptor in cardiorenal injury in T2DM.

AREAS COVERED

Finerenone is a selective and nonsteroidal mineralocorticoid receptor antagonist that reduces -on preclinical studies- heart and kidney inflammation and fibrosis. Clinical trials have demonstrated that among patients with T2DM and CKD, finerenone reduces CKD progression and the risk of cardiovascular events. The incidence of adverse events is similar than for placebo. Permanent discontinuation of study drug due to hyperkalemia was low (1.7% of finerenone and 0.6% of placebo participants) as was the risk of hyperkalemia-related severe-adverse events (1.1%). We provide an overview of risk factors for hyperkalemia and management of serum potassium in people with CKD and T2DM on finerenone.

EXPERT OPINION

As finerenone increases potassium levels in a predictable way, patients at risk of hyperkalemia can be identified early in clinical practice and monitored for an easy management. This will allow people with T2DM and CKD to safely benefit from improved cardiorenal outcomes.

Regulated cell death pathways in kidney disease

Disorders of cell number that result from an imbalance between the death of parenchymal cells and the proliferation or recruitment of maladaptive cells contributes to the pathogenesis of kidney disease. Acute kidney injury can result from an acute loss of kidney epithelial cells. In chronic kidney disease, loss of kidney epithelial cells leads to glomerulosclerosis and tubular atrophy, whereas interstitial inflammation and fibrosis result from an excess of leukocytes and myofibroblasts. Other conditions, such as acquired cystic disease and kidney cancer, are characterized by excess numbers of cyst wall and malignant cells, respectively. Cell death modalities act to clear unwanted cells, but disproportionate responses can contribute to the detrimental loss of kidney cells. Indeed, pathways of regulated cell death - including apoptosis and necrosis - have emerged as central events in the pathogenesis of various kidney diseases that may be amenable to therapeutic intervention. Modes of regulated necrosis, such as ferroptosis, necroptosis and pyroptosis may cause kidney injury directly or through the recruitment of immune cells and stimulation of inflammatory responses. Importantly, multiple layers of interconnections exist between different modalities of regulated cell death, including shared triggers, molecular components and protective mechanisms.

Kidney transplant in the next decade: Strategies, challenges and vision of the future

Although the results of kidney transplantation (KT) have improved substantially in recent years, a chronic and inexorable loss of grafts mainly due to the death of the patient and chronic dysfunction of the KT, continues to be observed. The objectives, thus, to optimize this situation in the next decade are fundamentally focused on minimizing the rate of kidney graft loss, improving patient survival, increasing the rate of organ procurement and its distribution, promoting research and training in health professionals and the development of scientific registries providing clinical and reliable information that allow us to optimize our clinical practice in the field of KT. With this perspective, this review will deep into: (1) strategies to avoid chronic dysfunction and graft loss in the medium and long term; (2) to prolong patient survival; (3) strategies to increase the donation, maintenance and allocation of organs; (4) promote clinical and basic research and training activity in KT; and (5) the analysis of the results in KT by optimizing and merging scientific registries.

Novel Aspects of the Immune Response Involved in the Peritoneal Damage in Chronic Kidney Disease Patients under Dialysis

Chronic kidney disease (CKD) incidence is growing worldwide, with a significant percentage of CKD patients reaching end-stage renal disease (ESRD) and requiring kidney replacement therapies (KRT). Peritoneal dialysis (PD) is a convenient KRT presenting benefices as home therapy. In PD patients, the peritoneum is chronically exposed to PD fluids containing supraphysiologic concentrations of glucose or other osmotic agents, leading to the activation of cellular and molecular processes of damage, including inflammation and fibrosis. Importantly, peritonitis episodes enhance peritoneum inflammation status and accelerate peritoneal injury. Here, we review the role of immune cells in the damage of the peritoneal membrane (PM) by repeated exposure to PD fluids during KRT as well as by bacterial or viral infections. We also discuss the anti-inflammatory properties of current clinical treatments of CKD patients in KRT and their potential effect on preserving PM integrity. Finally, given the current importance of coronavirus disease 2019 (COVID-19) disease, we also analyze here the implications of this disease in CKD and KRT.

Vitamin D, Cellular Senescence and Chronic Kidney Diseases: What Is Missing in the Equation?

As life expectancy increases in many countries, the prevalence of age-related diseases also rises. Among these conditions, chronic kidney disease is predicted to become the second cause of death in some countries before the end of the century. An important problem with kidney diseases is the lack of biomarkers to detect early damage or to predict the progression to renal failure. In addition, current treatments only retard kidney disease progression, and better tools are needed. Preclinical research has shown the involvement of the activation of cellular senescence-related mechanisms in natural aging and kidney injury. Intensive research is searching for novel treatments for kidney diseases as well as for anti-aging therapies. In this sense, many experimental shreds of evidence support that treatment with vitamin D or its analogs can exert pleiotropic protective effects in kidney injury. Moreover, vitamin D deficiency has been described in patients with kidney diseases. Here, we review recent evidence about the relationship between vitamin D and kidney diseases, explaining the underlying mechanisms of the effect of vitamin D actions, with particular attention to the modulation of cellular senescence mechanisms.

Ageing meets kidney disease

Chronic kidney disease (CKD) is defined as abnormalities of kidney structure or function, present for ˃3 months, with implications for health. The most used diagnostic criteria are a urinary albumin: creatinine ratio ≥30 mg/g or an estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m2. Either of these diagnostic thresholds is associated with adverse health outcomes. GFR decreases with age and the prevalence of CKD is highest in older adults; moreover, the presence of CKD is associated with an increased risk of all-cause and cardiovascular death related to accelerated ageing in all age ranges, and the absolute increase in risk is highest for those aged ˃75 years. Indeed, premature death is a more common outcome than CKD progression to kidney failure requiring kidney replacement therapy. The progressive ageing of the world population contributes to the projection that CKD will become the second most common cause of death before the end of the century in countries with long life expectancy. The current collection of selected studies on kidney disease and ageing published in Age&Ageing, NDT and CKJ provides an overview of key topics, including cognitive decline, sarcopaenia, wasting and cardiovascular and non-cardiovascular morbidity and mortality, the management of kidney failure and gender differences in CKD progression.