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Chronic kidney disease (CKD) causes skeletal muscle wasting, resulting in reduced function and inability to live independently. This systematic review critically appraised the scientific literature regarding the effects of full-body resistance training on clinically-relevant functional capacity measures in CKD. The study population included studies of people with Stage 4 or 5 CKD and a mean age of 40+ years old. Eight databases were searched for eligible studies: Pubmed, Embase, Cochrane, CINAHL, Scopus, Web of Science, MEDLINE, and AGELINE. MeSH terms and keyword combinations were used for screening following the PRISMA conduct. Inclusion criteria were based on PICO principles and no date of publication filter was applied. The intervention was training 2 days/week of structured resistance exercises using major upper and lower muscle groups. Minimum intervention period was 7 weeks. Comparison groups maintained their habitual activity without structured exercise training. Outcome measures of interest were: 6-min walk test, grip strength, timed up-and-go test, and sit-to-stand. Eight randomized controlled trials and one nonequivalent comparison-group study fulfilled the inclusion criteria and underwent data extraction. All studies were of hemodialysis patients. The evidence indicates that full-body resistance exercise significantly improved grip strength, timed up and go and sit to stand tests; metrics associated with enhanced quality and quantity of life., (© 2024 The Author(s). Physiological Reports published by Wiley Periodicals LLC on behalf of The Physiological Society and the American Physiological Society.)

Background: Clonal hematopoiesis of indeterminate potential (CHIP) is a common inflammatory condition of aging that causes myriad end-organ damage. We have recently shown associations for CHIP with acute kidney injury and with kidney function decline in the general population, with stronger associations for CHIP driven by mutations in genes other than DNMT3A (non- DNMT3A CHIP). Longitudinal kidney function endpoints in individuals with pre-existing chronic kidney disease (CKD) and CHIP have been examined in two previous studies, which reported conflicting findings and were limited by small sample sizes., Methods: In this study, we examined the prospective associations between CHIP and CKD progression events in four cohorts of CKD patients (total N = 5,772). The primary outcome was a composite of 50% kidney function decline or kidney failure. The slope of eGFR decline was examined as a secondary outcome. Mendelian randomization techniques were then used to investigate potential causal effects of CHIP on eGFR decline. Finally, kidney function was assessed in adenine-fed CKD model mice having received a bone marrow transplant recapitulating Tet2 -CHIP compared to controls transplanted wild-type bone marrow., Results: Across all cohorts, the average age was 66.4 years, the average baseline eGFR was 42.6 ml/min/1.73m 2 , and 24% had CHIP. Upon meta-analysis, non- DNMT3A CHIP was associated with a 59% higher relative risk of incident CKD progression (HR 1.59, 95% CI: 1.02-2.47). This association was more pronounced among individuals with diabetes (HR 1.29, 95% CI: 1.03-1.62) and with baseline eGFR ≥ 30 ml/min/1.73m (HR 1.80, 95% CI: 1.11-2.90). Additionally, the annualized slope of eGFR decline was steeper among non- DNMT3A CHIP carriers, relative to non-carriers (β -0.61 ± 0.31 ml/min/1.73m 2 , p = 0.04). Mendelian randomization analyses suggested a causal role for CHIP in eGFR decline among individuals with diabetes. In a dietary adenine mouse model of CKD, Tet2 -CHIP was associated with lower GFR as well as greater kidney inflammation, tubular injury, and tubulointerstitial fibrosis., Conclusion: Non- DNMT3A CHIP is a potentially targetable novel risk factor for CKD progression.

Background: Low total kidney volume (TKV) is a risk factor for chronic kidney disease (CKD). However, evaluations of nonlinear relationships, incident events, causal inference, and prognostic utility beyond traditional biomarkers are lacking., Methods: TKV, height-adjusted TKV, and body surface area-adjusted TKV (BSA-TKV) of 34,595 White British ancestry participants were derived from the UK Biobank. Association with incident CKD, acute kidney injury (AKI), and cardiovascular events were assessed with Cox proportional hazard models. Prognostic thresholds for CKD risk stratification were identified using a modified Mazumdar method with bootstrap resampling. Two-sample Mendelian randomization was performed to assess the bidirectional association of genetically predicted TKV with kidney and cardiovascular traits., Results: Adjusted for eGFR and albuminuria, a lower TKV of 10 mL was associated with a 6% higher risk of incident CKD (hazard ratio [HR] 1.06, 95% confidence interval [CI] 1.03 to 1.08, P = 5.8 x 10-6) in contrast to no association with incident AKI (HR 1.00, 95% CI 0.98 to 1.02, P = 0.66). Comparison of nested models demonstrated improved accuracy over the CKD Prognosis Consortium Incident CKD Risk Score with the addition of BSA-TKV or prognostic thresholds at 119 (10th percentile) and 145 mL/m2 (50th percentile). In Mendelian randomization, a lower genetically predicted TKV by 10 mL was associated with 10% higher CKD risk (odds ratio [OR] 1.10, 95% CI 1.06 to 1.14, P = 1.3 x 10-7). Reciprocally, an elevated risk of genetically predicted CKD by 2-fold was associated with a lower TKV by 7.88 mL (95% CI -9.81 to -5.95, P = 1.2 x 10-15). There were no significant observational or Mendelian randomization associations of TKV with cardiovascular complications., Conclusions: Kidney volume was associated with incident CKD independent of traditional risk factors including baseline eGFR and albuminuria. Mendelian randomization demonstrated a bidirectional relationship between kidney volume and CKD., (Copyright © 2024 by the American Society of Nephrology.)

Clonal haematopoiesis of indeterminate potential (CHIP) is a preclinical condition wherein a sizeable proportion of an individual's circulating blood cells are derived from a single mutated haematopoietic stem cell. CHIP occurs frequently with ageing - more than 10% of individuals over 65 years of age are affected - and is associated with an increased risk of disease across several organ systems and premature death. Emerging evidence suggests that CHIP has a role in kidney health, including associations with predisposition to acute kidney injury, impaired recovery from acute kidney injury and kidney function decline, both in the general population and among those with chronic kidney disease. Beyond its direct effect on the kidney, CHIP elevates the susceptibility of individuals to various conditions that can detrimentally affect the kidneys, including cardiovascular disease, obesity and insulin resistance, liver disease, gout, osteoporosis and certain autoimmune diseases. Aberrant pro-inflammatory signalling, telomere attrition and epigenetic ageing are potential causal pathophysiological pathways and mediators that underlie CHIP-related disease risk. Experimental animal models have shown that inhibition of inflammatory cytokine signalling can ameliorate many of the pathological effects of CHIP, and assessment of the efficacy and safety of this class of medications for human CHIP-associated pathology is ongoing., (© 2023. Springer Nature Limited.)

Age is a predominant risk factor for acute kidney injury (AKI), yet the biological mechanisms underlying this risk are largely unknown. Clonal hematopoiesis of indeterminate potential (CHIP) confers increased risk for several chronic diseases associated with aging. Here we sought to test whether CHIP increases the risk of AKI. In three population-based epidemiology cohorts, we found that CHIP was associated with a greater risk of incident AKI, which was more pronounced in patients with AKI requiring dialysis and in individuals with somatic mutations in genes other than DNMT3A, including mutations in TET2 and JAK2. Mendelian randomization analyses supported a causal role for CHIP in promoting AKI. Non-DNMT3A-CHIP was also associated with a nonresolving pattern of injury in patients with AKI. To gain mechanistic insight, we evaluated the role of Tet2-CHIP and Jak2 V617F -CHIP in two mouse models of AKI. In both models, CHIP was associated with more severe AKI, greater renal proinflammatory macrophage infiltration and greater post-AKI kidney fibrosis. In summary, this work establishes CHIP as a genetic mechanism conferring impaired kidney function recovery after AKI via an aberrant inflammatory response mediated by renal macrophages., (© 2024. The Author(s).)

Thousands of pathogenic variants in more than 100 genes can cause kidney cysts with substantial variability in phenotype and risk of subsequent kidney failure. Despite an established genotype-phenotype correlation in cystic kidney diseases, incomplete penetrance and variable disease expressivity are present as is the case in all monogenic diseases. In family members with autosomal dominant polycystic kidney disease (ADPKD), the same causal variant is responsible in all affected family members; however, there can still be striking discordance in phenotype severity. This narrative review explores contributors to within-family discordance in ADPKD severity. Cases of biallelic and digenic inheritance, where 2 rare pathogenic variants in cystogenic genes are coexistent in one family, account for a small proportion of within-family discordance. Genetic background, including cis and trans factors and the polygenic propensity for comorbid disease, also plays a role but has not yet been exhaustively quantified. Environmental exposures, including diet; smoking; alcohol, salt, and protein intake, and comorbid diseases, including obesity, diabetes, hypertension, kidney stones, dyslipidemia, and additional coexistent kidney diseases all contribute to ADPKD phenotypic variability among family members. Given that many of the factors contributing to phenotype variability are preventable, modifiable, or treatable, health care providers and patients need to be aware of these factors and address them in the treatment of ADPKD., (© 2024 International Society of Nephrology. Published by Elsevier Inc.)

Chronic kidney disease is a leading cause of death and disability globally and impacts individuals of African ancestry (AFR) or with ancestry in the Americas (AMS) who are under-represented in genome-wide association studies (GWASs) of kidney function. To address this bias, we conducted a large meta-analysis of GWASs of estimated glomerular filtration rate (eGFR) in 145,732 AFR and AMS individuals. We identified 41 loci at genome-wide significance (p < 5 × 10 -8 ), of which two have not been previously reported in any ancestry group. We integrated fine-mapped loci with epigenomic and transcriptomic resources to highlight potential effector genes relevant to kidney physiology and disease, and reveal key regulatory elements and pathways involved in renal function and development. We demonstrate the varying but increased predictive power offered by a multi-ancestry polygenic score for eGFR and highlight the importance of population diversity in GWASs and multi-omics resources to enhance opportunities for clinical translation for all., Competing Interests: Declaration of interests P.N. reports investigator-initiated research grants from Allelica, Apple, Amgen, Boston Scientific, Genentech/Roche, and Novartis, personal fees from Allelica, Apple, AstraZeneca, Blackstone Life Sciences, Eli Lilly & Co, Foresite Labs, Genentech/Roche, GV, HeartFlow, Magnet Biomedicine, and Novartis, scientific advisory board membership of Esperion Therapeutics, Preciseli, and TenSixteen Bio, scientific co-founder of TenSixteen Bio, equity in MyOme, Preciseli, and TenSixteen Bio, and spousal employment at Vertex Pharmaceuticals, all unrelated to the present work. M.B.L. has received speaker and advisory fees from Otsuka, Reata, Bayer, and Sanofi Genzyme. G.P. has received speaker and advisory fees from Amgen, Bayer, Novartis, and Sanofi, and has received research grants from Bayer and Sanofi. L.M.R. is a consultant for the TOPMed Administrative Coordinating Center (through Westat)., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Purpose of Review: Multiple large-scale genome-wide association meta-analyses studies have reliably identified an association between genetic variants within the SHROOM3 gene and chronic kidney disease. This association extends to alterations in known markers of kidney disease including baseline estimated glomerular filtration rate, urinary albumin-to-creatinine ratio, and blood urea nitrogen. Yet, an understanding of the molecular mechanisms behind the association of SHROOM3 and kidney disease remains poorly communicated. We conducted a narrative review to summarize the current state of literature regarding the genetic and molecular relationships between SHROOM3 and kidney development and disease., Sources of Information: PubMed, PubMed Central, SCOPUS, and Web of Science databases, as well as review of references from relevant studies and independent Google Scholar searches to fill gaps in knowledge., Methods: A comprehensive narrative review was conducted to explore the molecular mechanisms underlying SHROOM3 and kidney development, function, and disease., Key Findings: SHROOM3 is a unique protein, as it is the only member of the SHROOM group of proteins that regulates actin dynamics through apical constriction and apicobasal cell elongation. It holds a dichotomous role in the kidney, as subtle alterations in SHROOM3 expression and function can be both pathological and protective toward kidney disease. Genome-wide association studies have identified genetic variants near the transcription start site of the SHROOM3 gene associated with chronic kidney disease. SHROOM3 also appears to protect the glomerular structure and function in conditions such as focal segmental glomerulosclerosis. However, little is known about the exact mechanisms by which this protection occurs, which is why SHROOM3 binding partners remain an opportunity for further investigation., Limitations: Our search was limited to English articles. No structured assessment of study quality was performed, and selection bias of included articles may have occurred. As we discuss future directions and opportunities, this narrative review reflects the academic views of the authors., Competing Interests: The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article., (© The Author(s) 2023.)

Estimated glomerular filtration rate (eGFR) impacts the concentration of plasma biomarkers confounding biomarker association studies of eGFR with reverse causation. To identify biomarkers causally associated with eGFR, we performed a proteome-wide Mendelian randomization study. Genetic variants nearby biomarker coding genes were tested for association with plasma concentration of 1,161 biomarkers in a multi-ancestry sample of 12,066 participants from the Prospective Urban and Rural Epidemiological (PURE) study. Using two-sample Mendelian randomization, individual variants' effects on biomarker concentration were correlated with their effects on eGFR and kidney traits from published genome-wide association studies (GWAS). Genetically altered concentrations of 22 biomarkers were associated with eGFR above a Bonferroni-corrected significance threshold. Five biomarkers were previously identified by GWAS (UMOD, FGF5, LGALS7, NINJ1, COL18A1). Nine biomarkers were within 1 Mb of the lead GWAS variant but the gene for the biomarker was unidentified as the candidate for the GWAS signal (INHBC, TNFRSF11A, TCN2, PXN1, PRTN3, PSMD9, TFPI, ITGB6, CA3). Single-cell transcriptomic data indicated the 22 biomarkers are expressed in kidney tubules, collecting duct, fibroblasts, and immune cells. Pathway analysis showed significant enrichment of identified biomarkers in the extracellular kidney parenchyma. Thus, using genetic regulators of biomarker concentration via proteome-wide Mendelian randomization, we identified 22 biomarkers that appear to causally impact eGFR in either a beneficial or adverse manner. The current study provides rationale for novel therapeutic targets for eGFR and emphasized a role for extracellular proteins produced by tubular cells and fibroblasts for impacting eGFR., (Copyright © 2023 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.)

Competing Interests: Intérêts concurrents: Matthew Lanktree a reçu des honoraires de conférencier d’Otsuka et des honoraires pour sa participation à des comités consultatifs pour Bayer, Otsuka, Reata et Sanofi. Ces honoraires étaient sans lien avec les inhibiteurs du SGLT2. Aucun autre intérêt concurrent n’a été déclaré.

While autosomal dominant polycystic kidney disease (ADPKD) is a dichotomous diagnosis, substantial variability in disease severity exists. Identification of inherited risk through family history, genetic testing, and environmental risk factors through clinical assessment are important components of risk assessment for optimal management of patients with ADPKD. Genetic testing is especially helpful in cases with diagnostic uncertainty, particularly in cases with no apparent family history, in young cases (age less than 25 years) where a definitive diagnosis is sought, or in atypical presentations with early, severe, or discordant findings. Currently, risk assessment in ADPKD may be performed with the use of age-adjusted estimated glomerular filtration rate thresholds, evidence of rapid estimated glomerular filtration rate decline on serial measurements, age- and height-adjusted total kidney volume by Mayo Clinic Imaging Classification, or evidence of early hypertension and urological complications combined with PKD1 or PKD2 mutation class; however, caveats exist with each of these approaches. Fine-tuning of risk stratification with advanced imaging features and biomarkers is the subject of research but is not yet ready for general clinical practice. While conservative treatment strategies will be advised for all patients, those with the greatest rate of disease progression will have the most benefit from aggressive disease-modifying therapy. In this narrative review, we will summarize the evidence behind the clinical assessment and risk stratification of patients with ADPKD., (Copyright © 2023 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.)

Background: Loin pain hematuria syndrome (LPHS) is a poorly understood clinical syndrome characterized by hematuria and either unilateral or bilateral severe kidney pain in the absence of identifiable urological disease. Loin pain hematuria syndrome imposes a significant health and economic impact with a loss of productivity and quality of life in a young population. Owing to an incomplete understanding of its pathophysiology, treatment has been limited to nonspecific pain management. Nearly 60 years after its initial description, we are no further ahead in understanding the molecular pathways involved in LPHS., Objective: To outline the study design for exome sequencing in adults with LPHS and their families., Methods: In this single-center case series, 24 patients with LPHS and 2 additional first-degree family members per participant will be recruited. DNA extracted from venous blood samples will undergo exome sequencing on the Illumina NovaSeq 6000 System at 100× depth and will be assessed for pathogenic variants in genes associated with hematuria (number of genes in: glomerular endothelium [n = 10] and basement membrane [n = 8]), and pain pathways (number of genes in: pain transduction [n = 17], conduction [n = 8], synaptic transmission [n = 37], and modulation [n = 27]). We will further examine identified potentially pathogenic variants that co-segregate with LPHS features among affected families., Conclusions: This pilot study may identify new directions for an investigation into the molecular mechanisms underlying LPHS., Competing Interests: The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: BP has received speaker and advisory fees from Bayer, Otsuka and Astra Zeneca. MBL has received speaker and advisory fees from Otsuka, Reata, Bayer, and Sanofi Genzyme., (© The Author(s) 2023.)

Clonal hematopoiesis of indeterminate potential (CHIP) is a common form of age-related somatic mosaicism that is associated with significant morbidity and mortality. CHIP mutations can be identified in peripheral blood samples that are sequenced using approaches that cover the whole genome, the whole exome, or targeted genetic regions; however, differentiating true CHIP mutations from sequencing artifacts and germ line variants is a considerable bioinformatic challenge. We present a stepwise method that combines filtering based on sequencing metrics, variant annotation, and population-based associations to increase the accuracy of CHIP calls. We apply this approach to ascertain CHIP in ∼550 000 individuals in the UK Biobank complete whole exome cohort and the All of Us Research Program initial whole genome release cohort. CHIP ascertainment on this scale unmasks recurrent artifactual variants and highlights the importance of specialized filtering approaches for several genes, including TET2 and ASXL1. We show how small changes in filtering parameters can considerably increase CHIP misclassification and reduce the effect size of epidemiological associations. Our high-fidelity call set refines previous population-based associations of CHIP with incident outcomes. For example, the annualized incidence of myeloid malignancy in individuals with small CHIP clones is 0.03% per year, which increases to 0.5% per year among individuals with very large CHIP clones. We also find a significantly lower prevalence of CHIP in individuals of self-reported Latino or Hispanic ethnicity in All of Us, highlighting the importance of including diverse populations. The standardization of CHIP calling will increase the fidelity of CHIP epidemiological work and is required for clinical CHIP diagnostic assays., (© 2023 by The American Society of Hematology.)

Competing Interests: Competing interests: Matthew Lanktree has received speaking fees from Otsuka and advisory board fees from Bayer, Otsuka, Reata and Sanofi. Speaking and advisory board fees were unrelated to SGLT2 inhibitors. No other competing interests were declared.

Rationale & Objective: Clonal hematopoiesis of indeterminate potential (CHIP), defined by the age-related ontogenesis of expanded leukemogenic variants indicative of a genetically distinct clonal leukocyte population, is associated with risk of hematologic malignancy and cardiovascular disease. In experimental models, recapitulation of CHIP promotes kidney interstitial fibrosis with direct tissue infiltration of donor macrophages. We tested the hypothesis that CHIP is associated with kidney function decline in the general population., Study Design: Cohort study., Setting & Participants: 12,004 individuals from 3 community-based cohorts in the TOPMed Consortium., Exposure: CHIP status from whole-genome sequences obtained from DNA extracted from peripheral blood., Outcome: Risk of 30% decline in estimated glomerular filtration rate (eGFR) and percent eGFR decline per year during the follow-up period., Analytical Approach: Cox proportional hazards models for 30% eGFR decline end point and generalized estimating equations for annualized relative change in eGFR with meta-analysis. Study-specific estimates were combined using fixed-effect meta-analysis., Results: The median baseline eGFR was 84mL/min/1.73m 2 . The prevalence of CHIP was 6.6%, 9.0%, and 12.2% in persons aged 50-60, 60-70, and>70 years, respectively. Over a median follow-up period of 8 years, for the 30% eGFR outcome 205 events occurred among 1,002 CHIP carriers (2.1 events per 100 person-years) and 2,041 events in persons without CHIP (1.7 events per 100 person-years). In meta-analysis, CHIP was associated with greater risk of a 30% eGFR decline (17% [95% CI, 1%-36%] higher; P=0.04). Differences were not observed between those with baseline eGFR above or below 60mL/min/1.73m 2 , of age above or below 60 years, or with or without diabetes., Limitations: Small number of participants with moderate-to-advanced kidney disease and restricted set of CHIP driver variants., Conclusions: We report an association between CHIP and eGFR decline in 3 general population cohorts without known kidney disease. Further studies are needed to investigate this novel condition and its potential impact among individuals with overt kidney disease., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

Introduction: Loin pain hematuria syndrome (LPHS) is a rare clinical syndrome with a reported prevalence of 1 in 10,000. The syndrome is characterized by severe pain localized to the kidney in the absence of identifiable urinary tract disease. Because of an inadequate understanding of the pathophysiology of the disease, the goal of management has been limited to symptomatic pain management. Through detailed phenotype and genotype assessment we sought to identify possible underlying etiologies., Methods: We completed a chart review, ultrasound imaging, kidney biopsy, and type IV collagen ( COL4A3 , COL4A4 , and COL4A5 ) gene sequencing in 14 patients with loin pain hematuria recruited from a single center., Results: Red blood cells and red cell casts were observed within the tubules in 10 of 14 patients. The glomerular basement membrane (GBM) was normal in 11 patients and thickened in 1 patient. Staining for IgA kappa was present in 1 patient. C3 deposition without any inflammation was present in 7 patients. Arteriolar hyalinosis was present in 4 patients and endothelial cell injury was present in 6 patients. No pathogenic COL4A3 , COL4A4 , or COL4A5 variants were identified., Conclusion: Conventional histopathology and genetic testing for type IV collagen variants failed to identify the cause of hematuria in 14 patients with LPHS., (© 2023 Published by Elsevier Inc. on behalf of the International Society of Nephrology.)

Using age- and height-adjusted total kidney volume, the Mayo Clinic Imaging Classification provides a validated approach to assess the risk of chronic kidney disease (CKD) progression in autosomal dominant polycystic kidney disease (ADPKD), but requires excluding patients with atypical imaging patterns, whose clinical characteristics have been poorly defined. We report an analysis of the prevalence, clinical and genetic characteristics of patients with atypical polycystic kidney disease by imaging. Patients from the extended Toronto Genetic Epidemiology Study of Polycystic Kidney Disease recruited between 2016 and 2018 completed a standardized clinical questionnaire, kidney function assessment, genetic testing, and kidney imaging by magnetic resonance or computed tomography. We compared the prevalence, clinical features, genetics, and renal prognosis of atypical versus typical polycystic kidney disease by imaging. Forty-six of the 523 (8.8%) patients displayed atypical polycystic kidney disease by imaging; they were older (55 vs. 43 years; P < 0.001), and less likely to have a family history of ADPKD (26.1% vs. 74.6%; P < 0.001), a detectable PKD1 or PKD2 mutation (9.2% vs. 80.4%; P < 0.001), or progression to CKD stage 3 or stage 5 (P < 0.001). Patients with atypical polycystic kidney disease by imaging represent a distinct prognostic group with a low likelihood of progression to CKD., (© 2022. The Author(s).)

Background: Clonal hematopoiesis of indeterminate potential (CHIP) is an inflammatory premalignant disorder resulting from acquired genetic mutations in hematopoietic stem cells. This condition is common in aging populations and associated with cardiovascular morbidity and overall mortality, but its role in CKD is unknown., Methods: We performed targeted sequencing to detect CHIP mutations in two independent cohorts of 87 and 85 adults with an eGFR<60 ml/min per 1.73m 2 . We also assessed kidney function, hematologic, and mineral bone disease parameters cross-sectionally at baseline, and collected creatinine measurements over the following 5-year period., Results: At baseline, CHIP was detected in 18 of 87 (21%) and 25 of 85 (29%) cohort participants. Participants with CHIP were at higher risk of kidney failure, as predicted by the Kidney Failure Risk Equation (KFRE), compared with those without CHIP. Individuals with CHIP manifested a 2.2-fold increased risk of a 50% decline in eGFR or ESKD over 5 years of follow-up (hazard ratio 2.2; 95% confidence interval, 1.2 to 3.8) in a Cox proportional hazard model adjusted for age, sex, and baseline eGFR. The addition of CHIP to 2-year and 5-year calibrated KFRE risk models improved ESKD predictions. Those with CHIP also had lower hemoglobin, higher ferritin, and higher red blood cell mean corpuscular volume versus those without CHIP., Conclusions: In this exploratory analysis of individuals with preexisting CKD, CHIP was associated with higher baseline KFRE scores, greater progression of CKD, and anemia. Further research is needed to define the nature of the relationship between CHIP and kidney disease progression., (Copyright © 2022 by the American Society of Nephrology.)

Background: Atrial fibrillation (AF) is a cardiac arrhythmia associated with an elevated risk of stroke, heart failure, and mortality. However, preventative therapies are needed with ancillary benefits on its cardiovascular comorbidities. Lipoprotein(a) (Lp[a]) is a recognized risk factor for atherosclerotic cardiovascular disease (ASCVD), which itself increases AF risk, but it remains unknown whether Lp(a) is a causal mediator of AF independent of ASCVD., Objectives: This study investigated the role of Lp(a) in AF and whether it is independent of ASCVD., Methods: Measured and genetically predicted Lp(a) levels were tested for association with 20,432 cases of incident AF in the UK Biobank (N = 435,579). Mendelian randomization analyses were performed by using summary-level data for AF from publicly available genome-wide association studies (N = 1,145,375)., Results: In the UK Biobank, each 50 nmol/L (23 mg/dL) increase in Lp(a) was associated with an increased risk of incident AF using measured Lp(a) (HR: 1.03; 95% CI: 1.02-1.04 ; P = 1.65 × 10 -8 ) and genetically predicted Lp(a) (OR: 1.03; 95% CI: 1.02-1.05; P = 1.33 × 10 -5 ). Mendelian randomization analyses using independent data replicated the effect (OR: 1.04 per 50 nmol/L Lp[a] increase; 95% CI: 1.03-1.05 per 50 nmol/L Lp[a] increase; P = 9.23 × 10 -10 ). There was no evidence of risk-conferring effect from low-density lipoprotein cholesterol or triglycerides, and only 39% (95% CI: 27%-73%) of Lp(a) risk was mediated through ASCVD, suggesting that Lp(a) partly influences AF independent of its known effects on ASCVD., Conclusions: Our findings implicate Lp(a) as a potential causal mediator in the development of AF which show that the effects of Lp(a) extend across myocardial tissues. Ongoing clinical trials for Lp(a)-lowering therapies should evaluate effects on AF prevention., Competing Interests: Funding Support and Author Disclosures Mr Mohammadi-Shemirani and Mr Chong are supported by the Frederick Banting and Charles Best Canada Graduate Scholarship from the Canadian Institute of Health Research. Dr Conen holds a McMaster University Department of Medicine Mid-Career Research Award; and has received consulting fees from Roche Diagnostics, outside of the current work. Dr Thériault holds a junior scholar award from the FRQS (Fonds de recherche du Québec–Santé). Dr Bossé holds a Canada Research Chair in Genomics of Heart and Lung Diseases. Dr Lanktree is a new investigator in the KRESCENT (Kidney Research Scientist Core Education and National Training) program; is supported by the Canadian Institutes of Health Research, Kidney Foundation of Canada, and the Canadian Society of Nephrology; and has received compensation for participation as a speaker and an advisory board member for Otsuka, Reata, Sanofi Genzyme, and Bayer. Dr Pigeyre is supported by the E.J. Moran Campbell Internal Career Research Award from McMaster University. Dr Paré holds the Canada Research Chair in Genetic and Molecular Epidemiology and Cisco Systems Professorship in Integrated Health Biosystems. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

Introduction: Adenosine triphosphate-citrate lyase (ACLY) inhibition is a therapeutic strategy under investigation for atherosclerotic cardiovascular disease, nonalcoholic steatohepatitis, and metabolic syndrome. Mouse models suggest that ACLY inhibition could reduce inflammation and kidney fibrosis. Genetic analysis of ACLY in chronic kidney disease (CKD) has not been performed., Methods: We constructed a genetic instrument by selecting variants associated with ACLY expression in the expression quantitative trait loci genetics consortium (eQTLGen) from blood samples from 31,684 participants. In a 2-sample Mendelian randomization analysis, we evaluated the effect of genetically predicted ACLY expression on the risk of CKD, estimated glomerular filtration rate (eGFR), and albumin-to-creatinine ratio (ACR) using the CKD Genetics (CKDGen) consortium, UK Biobank, and the Finnish Genetics (FinnGen) consortium totaling 66,396 CKD cases and 958,517 controls., Results: ACLY is constitutively expressed in all cell types including in whole blood. The genetic instrument included 13 variants and explained 1.5% of the variation in whole blood ACLY gene expression. A 34% reduction in ACLY expression score was associated with a 0.04 mmol/l reduced low-density lipoprotein (LDL) cholesterol ( P  = 3.4 × 10 -4 ) and a 9% reduced risk of CKD (stages 3, 4, 5, dialysis, or eGFR < 60 ml/min per 1.73 m 2 ) (odds ratio [OR] = 0.91, 95% CI: 0.85-0.98, P  = 0.008), but no association was observed with either eGFR or ACR., Conclusion: Mendelian randomization analyses revealed that genetically reduced ACLY expression was associated with reduced risk of CKD but had no effect on either eGFR or ACR. Further evaluation of ACLY in kidney disease is warranted., (© 2022 International Society of Nephrology. Published by Elsevier Inc.)

Purpose of Review: Patients with autosomal dominant polycystic kidney disease (ADPKD) have kidney cysts and kidney enlargement decades before progressing to advanced chronic kidney disease (CKD), meaning patients live most of their adult life with a chronic medical condition. The coronavirus disease 2019 (COVID-19) pandemic has created common questions among patients with ADPKD. In this review, we discuss COVID-19 concerns centered around a patient with a common clinical vignette., Sources of Information: We performed PubMed and Google scholar searches for English, peer-reviewed studies related to "COVID-19," "ADPKD," "CKD," "tolvaptan," "angiotensin-converting enzyme inhibitors" (ACEi), "angiotensin receptor blockers" (ARB), and "vaccination." We also evaluated transplant data provided by the Ontario Trillium Gift of Life Network., Methods: Following an assessment of available literature, this narrative review addresses common questions of patients with ADPKD in the context of the COVID-19 pandemic., Key Findings: Data regarding the risk of developing COVID-19 and the risk of adverse COVID-19 outcomes in patients with ADPKD remain limited, but patients with ADPKD with impaired estimated glomerular filtration rate (eGFR), kidney transplants, or on dialysis are likely at similar increased risk as those with generally defined CKD. We provide strategies to improve virtual care, which is likely to persist after the pandemic. Current evidence suggests ACEi, ARB, and tolvaptan treatment should be continued unless contraindicated due to severe illness. When available, and in the absence of a severe allergy, vaccination is recommended for all patients with ADPKD., Limitations: This narrative review is limited by a paucity of high-quality data on COVID-19 outcomes in patients specifically with ADPKD., Implications: Patients with ADPKD who have developed advanced CKD, require dialysis, or who have received a kidney transplant are at elevated risk of COVID-19 complications., Competing Interests: Declaration of Conflicting Interests: The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: M.B.L. has received compensation as a speaker and advisory board member for Otsuka, Sanofi Genzyme, Reata, and Bayer. A.A. has received compensation as a speaker and advisory board member for Otsuka, Janssen, AstraZeneca, and Bayer. No other disclosures to report., (© The Author(s) 2021.)

Autosomal dominant polycystic kidney disease is the most common monogenic cause of ESKD. Genetic studies from patients and animal models have informed disease pathobiology and strongly support a "threshold model" in which cyst formation is triggered by reduced functional polycystin dosage below a critical threshold within individual tubular epithelial cells due to ( 1 ) germline and somatic PKD1 and/or PKD2 mutations, ( 2 ) mutations of genes ( e.g. , SEC63 , SEC61B , GANAB , PRKCSH , DNAJB11 , ALG8 , and ALG9 ) in the endoplasmic reticulum protein biosynthetic pathway, or ( 3 ) somatic mosaicism. Genetic testing has the potential to provide diagnostic and prognostic information in cystic kidney disease. However, mutation screening of PKD1 is challenging due to its large size and complexity, making it both costly and labor intensive. Moreover, conventional Sanger sequencing-based genetic testing is currently limited in elucidating the causes of atypical polycystic kidney disease, such as within-family disease discordance, atypical kidney imaging patterns, and discordant disease severity between total kidney volume and rate of eGFR decline. In addition, environmental factors, genetic modifiers, and somatic mosaicism also contribute to disease variability, further limiting prognostication by mutation class in individual patients. Recent innovations in next-generation sequencing are poised to transform and extend molecular diagnostics at reasonable costs. By comprehensive screening of multiple cystic disease and modifier genes, targeted gene panel, whole-exome, or whole-genome sequencing is expected to improve both diagnostic and prognostic accuracy to advance personalized medicine in autosomal dominant polycystic kidney disease., (Copyright © 2021 by the American Society of Nephrology.)

Preprint servers, such as arXiv and bioRxiv, have disrupted the scientific communication landscape by providing rapid access to research before peer review. medRxiv was launched as a free online repository for preprints in the medical, clinical, and related health sciences in 2019. In this review, we present the uptake of preprint server use in nephrology and discuss specific considerations regarding preprint server use in medicine. Distribution of kidney-related research on preprint servers is rising at an exponential rate. Survey of nephrology journals identified that 15 of 17 (88%) are publishing original research accepted submissions that have been uploaded to preprint servers. After reviewing 52 clinically impactful trials in nephrology discussed in the online Nephrology Journal Club (NephJC), an average lag of 300 days was found between study completion and publication, indicating an opportunity for faster research dissemination. Rapid review of papers discussing benefits and risks of preprint server use from the researcher, publisher, or end user perspective identified 53 papers that met criteria. Potential benefits of biomedical preprint servers included rapid dissemination, improved transparency of the peer review process, greater visibility and recognition, and collaboration. However, these benefits come at the risk of rapid spread of results not yet subjected to the rigors of peer review. Preprint servers shift the burden of critical appraisal to the reader. Media may be especially at risk due to their focus on "late-breaking" information. Preprint servers have played an even larger role when late-breaking research results are of special interest, such as during the global coronavirus disease 2019 pandemic. Coronavirus disease 2019 has brought both the benefits and risks of preprint servers to the forefront. Given the prominent online presence of the nephrology community, it is poised to lead the medicine community in appropriate use of preprint servers., (Copyright © 2021 by the American Society of Nephrology.)

Background and Objectives: Progression of autosomal dominant polycystic kidney disease (ADPKD) is highly variable. On average, protein-truncating PKD1 mutations are associated with the most severe kidney disease among all mutation classes. Here, we report that patients with protein-truncating PKD1 mutations may also have mild kidney disease, a finding not previously well recognized., Design, Setting, Participants, & Measurements: From the extended Toronto Genetic Epidemiologic Study of Polycystic Kidney Disease, 487 patients had PKD1 and PKD2 sequencing and typical ADPKD imaging patterns by magnetic resonance imaging or computed tomography. Mayo Clinic Imaging Classification on the basis of age- and height-adjusted total kidney volume was used to assess their cystic disease severity; classes 1A or 1B were used as a proxy to define mild disease. Multivariable linear regression was performed to test the effects of age, sex, and mutation classes on log-transformed height-adjusted total kidney volume and eGFR., Results: Among 174 study patients with typical imaging patterns and protein-truncating PKD1 mutations, 32 (18%) were found to have mild disease on the basis of imaging results ( i.e ., Mayo Clinic Imaging class 1A-1B), with their mutations spanning the entire gene. By multivariable analyses of age, sex, and mutation class, they displayed mild disease similar to patients with PKD2 mutations and Mayo Clinic Imaging class 1A-1B. Most of these mildly affected patients with protein-truncating PKD1 mutations reported a positive family history of ADPKD in preceding generations and displayed significant intrafamilial disease variability., Conclusions: Despite having the most severe mutation class, 18% of patients with protein-truncating PKD1 mutations had mild disease on the basis of clinical and imaging assessment., Podcast: This article contains a podcast at https://www.asn-online.org/media/podcast/CJASN/2021&#95;02&#95;18&#95;CJN11100720&#95;final.mp3., (Copyright © 2021 by the American Society of Nephrology.)

Purpose of Conference: On January 18, 2020, the Nephrology is Back learning day forum was held in Toronto, ON, Canada. The objectives of the meeting were to describe recent advances in nephrology for community and academic nephrologists and patients, and to define challenges and opportunities for integration of new data into clinical practice. The intent was to test a unique forum for continuing medical education integrating physician and patient experiences with the goal of encouraging change in practice., Sources of Information: Program content was based on current literature and clinical experience. Additional information was provided by patient partners who attended the meeting to provide their perspective on current issues in nephrology., Methods: A steering committee (A.L., A.S., and D.S.) developed goals and an outline for the content to be covered over the course of the meeting and led the recruitment of speakers. Speakers were asked to develop their presentations independently following direction by the committee, based on primary sources, including their own experiences. Presentations were followed by discussion including both physicians and patients, and participants had an opportunity to evaluate the conference and its outcomes., Key Findings: We present a unique approach to providing continuing medical education by including both physicians and patients in the learning process. Patient perspectives accompanying presentations around data and other clinical topics provided a much different environment from other knowledge translation exercises. We believe this represents an innovative approach for knowledge translation that allows physicians to address clinical topics in a novel manner, including the integration of new findings into practice and the need to cascade this education to their peers., Limitations: Because the conference was a one-time event, it has been difficult to assess the actual clinical impact of the knowledge translation exercise and whether physician behaviors have changed as a result of the activity. The conference could also have included broader representation from across Canada., Implications: The success of this test forum among both physicians and patient partners suggests that the inclusion of patient partners in learning could have an important role in future educational initiatives., Competing Interests: Declaration of Conflicting Interests: The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: A.L. has received compensation for participation as a speaker or an advisory board member, or has received research grant support from with AstraZeneca, Boehringer Ingelheim, Fresinius, Janssen, Otsuka, Reata, Certa, and Precision Medicine (KPMP). D.S. has received compensation for participation as a speaker or an advisory board member with AstraZeneca, Bayer, Janssen, Merck, and Otsuka. A.S. has received compensation for participation as a speaker or an advisory board member with AstraZeneca, Bayer, Boehringer Ingelheim/Lilly, Jansen, Merck, Otsuka, and Pfizer. D.C. has received consulting fees or honoraria from Boehringer Ingelheim, Lilly, Janssen, Merck, AstraZeneca, Mitsubishi-Tanabe, and Sanofi. I.C.H. declares no competing interests. M.B.L. has received compensation for participation as a speaker and an advisory board member with Otsuka Pharmaceuticals. L.M. has received advisory board funding or honoraria from Otsuka Pharmaceutical and Janssen. R.S.S. has received compensation for participation as a speaker or an advisory board member with Amgen, AstraZeneca, Otsuka, and Janssen., (© The Author(s) 2020.)

Purpose of Review: Sexual dysfunction occurs commonly in people with chronic kidney disease (CKD) and has been recognized as a research priority. We sought to evaluate the current state of the literature addressing sexual dysfunction in people with CKD and identify barriers and strategies to improve our management of this important symptom., Sources of Information: OVID Medline and Google Scholar were searched for English, peer-reviewed studies using keywords and terms related to "Chronic Kidney Disease," "sexuality," and "sexual dysfunction OR function.", Methods: In this narrative review, we describe definitions of sexual dysfunction and contributors exacerbated by CKD, barriers to researching sexual dysfunction in people with CKD, and possible avenues for future research., Key Findings: Sexual dysfunction is common in people with CKD and results from a combination of kidney disease itself, as well as its associated physical (ie, comorbidities) and nonphysical factors. Barriers to the study of sexual dysfunction in CKD include inconsistent disease definitions, stigma, variable efficacy and safety of established therapies, and evolving gender roles in sexual function. Potential avenues for future research to improve the sexual function in people with CKD may include evaluating the safety and efficacy of established therapies in people with CKD using a variety of observational and interventional study designs, engaging people with CKD and multidisciplinary team members in research, and using implementation science methods to translate what is known about sexual function into clinical practice. Concerted efforts are required to break down barriers and improve sexual function in people with CKD. Patients have identified this as an important research priority, and national networks need to direct efforts to reduce symptom burden., Limitations: This narrative review was limited by a paucity of high-quality studies examining sexual dysfunction specifically in people with kidney disease., Competing Interests: Declaration of Conflicting Interests: The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: M.B.L. has received compensation as a speaker and advisory board member for Otsuka Pharmaceutical. No other disclosures to report., (© The Author(s) 2020.)

Free open access medical education (FOAM) has disrupted traditional modes of knowledge translation and dissemination. These are popular resources with a wide educational reach. Nephrology has been a leader in FOAM, but many skeptics still question the accuracy and reliability of this content. Recently, quality-assurance techniques have been developed to address these concerns. These techniques may be helpful for readers to appraise the online literature and for institutions to reward the production of high-quality open educational resources. We performed a rapid review of the literature. A medical librarian conducted a systematic search of the Medline and Cumulative Index of Nursing and Allied Health Literature databases. Two independent assessors screened and selected articles, performed a hand-search of reference lists, and scored articles on their quality using the Medical Education Research Study Quality Instrument. Thirteen reports were included for the final descriptive analysis. We identified 10 quality-assessment techniques, and 4 of them having been validated. The quality of the reports was fairly high, with an average Medical Education Research Study Quality Instrument score of 11.5 of 18 (SD, 2.3; range, 7.25-14.25). The calculated Cronbach α was 0.85. There is burgeoning literature on the topic of critical appraisal of open educational resources, and, more specifically, FOAM resources. Many of the techniques used are of varying quality and developed with different intended uses and audiences. By continuing to refine these tools, we can continue not only to support and legitimize the FOAM movement, but also foster individual critical appraisal skills that increasingly are necessary in this age of information., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Competing Interests: Competing interests: Matthew Lanktree reports receiving compensation as a speaker and member of advisory boards for Otsuka Pharmaceuticals. No other competing interests were declared.

The prevalence of end-stage renal disease (ESRD) and the number of kidney transplants performed continues to rise every year, straining the procurement of deceased and living kidney allografts and health systems. Genome-wide genotyping and sequencing of diseased populations have uncovered genetic contributors in substantial proportions of ESRD patients. A number of these discoveries are beginning to be utilized in risk stratification and clinical management of patients. Specifically, genetics can provide insight into the primary cause of chronic kidney disease (CKD), the risk of progression to ESRD, and post-transplant outcomes, including various forms of allograft rejection. The International Genetics & Translational Research in Transplantation Network (iGeneTRAiN), is a multi-site consortium that encompasses >45 genetic studies with genome-wide genotyping from over 51,000 transplant samples, including genome-wide data from >30 kidney transplant cohorts (n = 28,015). iGeneTRAiN is statistically powered to capture both rare and common genetic contributions to ESRD and post-transplant outcomes. The primary cause of ESRD is often difficult to ascertain, especially where formal biopsy diagnosis is not performed, and is unavailable in ∼2% to >20% of kidney transplant recipients in iGeneTRAiN studies. We overview our current copy number variant (CNV) screening approaches from genome-wide genotyping datasets in iGeneTRAiN, in attempts to discover and validate genetic contributors to CKD and ESRD. Greater aggregation and analyses of well phenotyped patients with genome-wide datasets will undoubtedly yield insights into the underlying pathophysiological mechanisms of CKD, leading the way to improved diagnostic precision in nephrology., (Copyright © 2019 Fishman, Mohebnasab, van Setten, Zanoni, Wang, Deaglio, Amoroso, Callans, van Gelder, Lee, Kiryluk, Lanktree and Keating.)

Purpose: Autosomal dominant polycystic kidney disease (ADPKD) is characterized by progressive development of kidney cysts and enlargement and dysfunction of the kidneys. The Consortium of Radiologic Imaging Studies of the Polycystic Kidney Disease (CRISP) cohort revealed that 89.1% had either a PKD1 or PKD2 mutation. Of the CRISP patients with a genetic cause detected, mutations in PKD1 accounted for 85%, while mutations in the PKD2 accounted for the remaining 15%. Here, we report exome sequencing of 16 Saudi patients diagnosed with ADPKD and 16 ethnically matched controls. Methods: Exome sequencing was performed using combinatorial probe-anchor synthesis and improved DNA Nanoballs technology on BGISEQ-500 sequencers (BGI, China) using the BGI Exome V4 (59 Mb) Kit. Identified variants were validated with Sanger sequencing. Results: With the exception of GC-rich exon 1, we obtained excellent coverage of PKD1 (mean read depth = 88) including both duplicated and non-duplicated regions. Of nine patients with typical ADPKD presentations (bilateral symmetrical kidney involvement, positive family history, concordant imaging, and kidney function), four had protein truncating PKD1 mutations, one had a PKD1 missense mutation, and one had a PKD2 mutation. These variants have not been previously observed in the Saudi population. In seven clinically diagnosed ADPKD cases but with atypical features, no PKD1 or PKD2 mutations were identified, but rare predicted pathogenic heterozygous variants were found in cystogenic candidate genes including PKHD1, PKD1L3, EGF, CFTR , and TSC2 . Conclusions: Mutations in PKD1 and PKD2 are the most common cause of ADPKD in Saudi patients with typical ADPKD. Abbreviations: ADPKD: Autosomal dominant polycystic kidney disease; CFTR : Cystic fibrosis transmembrane conductance regulator; EGF : Epidermal growth factor; MCIC: Mayo Clinic Imaging Classification; PKD: Polycystic kidney disease; TSC2 : Tuberous sclerosis complex 2.