The Nephrotic Syndrome Study Network (NEPTUNE) is a North American multi-center collaborative consortium established to develop a translational research infrastructure for Nephrotic Syndrome. This includes a longitudinal observational cohort study, a pilot and ancillary studies program, a training program, and a patient contact registry. NEPTUNE will enroll 450 adults and children with minimal change disease, focal segmental glomerulosclerosis and membranous nephropathy for detailed clinical, histopathologic, and molecular phenotyping at the time of clinically-indicated renal biopsy. Initial visits will include an extensive clinical history, physical examination, collection of urine, blood and renal tissue samples, and assessments of quality of life and patient-reported outcomes. Follow-up history, physical measures, urine and blood samples, and questionnaires will be obtained every 4 months in the first year and bi-annually, thereafter. Molecular profiles and gene expression data will be linked to phenotypic, genetic, and digitalized histologic data for comprehensive analyses using systems biology approaches. Analytical strategies were designed to transform descriptive information to mechanistic disease classification for Nephrotic Syndrome and to identify clinical, histological, and genomic disease predictors. Thus, understanding the complexity of the disease pathogenesis will guide further investigation for targeted therapeutic strategies.

Expression quantitative trait loci (eQTL) studies illuminate the genetics of gene expression and, in disease research, can be particularly illuminating when using the tissues directly impacted by the condition. In nephrology, there is a paucity of eQTL studies of human kidney. Here, we used whole-genome sequencing (WGS) and microdissected glomerular (GLOM) and tubulointerstitial (TI) transcriptomes from 187 individuals with nephrotic syndrome (NS) to describe the eQTL landscape in these functionally distinct kidney structures. Using MatrixEQTL, we performed cis-eQTL analysis on GLOM (n = 136) and TI (n = 166). We used the Bayesian "Deterministic Approximation of Posteriors" (DAP) to fine-map these signals, eQTLBMA to discover GLOM- or TI-specific eQTLs, and single-cell RNA-seq data of control kidney tissue to identify the cell type specificity of significant eQTLs. We integrated eQTL data with an IgA Nephropathy (IgAN) GWAS to perform a transcriptome-wide association study (TWAS). We discovered 894 GLOM eQTLs and 1,767 TI eQTLs at FDR < 0.05. 14% and 19% of GLOM and TI eQTLs, respectively, had >1 independent signal associated with its expression. 12% and 26% of eQTLs were GLOM specific and TI specific, respectively. GLOM eQTLs were most significantly enriched in podocyte transcripts and TI eQTLs in proximal tubules. The IgAN TWAS identified significant GLOM and TI genes, primarily at the HLA region. In this study, we discovered GLOM and TI eQTLs, identified those that were tissue specific, deconvoluted them into cell-specific signals, and used them to characterize known GWAS alleles. These data are available for browsing and download via our eQTL browser, "nephQTL."

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This study describes the incidence, associated clinical characteristics and outcomes of acute kidney injury in a pediatric cohort with COVID-19 and Multisystem Inflammatory Syndrome in Children (MIS-C). We performed a retrospective study of patients 18 years of age and under admitted to four New York hospitals in the Northwell Health System interned during the height of the COVID-19 pandemic, between March 9 and August 13, 2020. Acute kidney injury was defined and staged according to Kidney Disease: Improving Global Outcomes criteria. The cohort included 152 patients; 97 acute-COVID-19 and 55 with MIS-C associated with COVID-19. Acute kidney injury occurred in 8 with acute-COVID-19 and in 10 with MIS-C. Acute kidney injury, in unadjusted models, was associated with a lower serum albumin level (odds ratio 0.17; 95% confidence interval 0.07, 0.39) and higher white blood cell counts (odds ratio 1.11; 95% confidence interval 1.04, 1.2). Patients with MIS-C and acute kidney injury had significantly greater rates of systolic dysfunction, compared to those without (80% vs 49%). In unadjusted models, patients with acute kidney injury had 8.4 days longer hospitalizations compared to patients without acute kidney injury (95% confidence interval, 4.4-6.7). Acute kidney injury in acute-COVID-19 and MIS-C may be related to inflammation and/or dehydration. Further research in larger pediatric cohorts is needed to better characterize risk factors for acute kidney injury in acute-COVID-19 and with MIS-C consequent to COVID-19.

Background The Patient Reported Outcomes Measurement Information System (PROMIS) II is a prospective study that evaluates patient reported outcomes in pediatric chronic diseases as a measure of health-related quality of life (HRQOL). We have evaluated the influence of disease duration on HRQOL and, for the first time, compared the findings of the PROMIS measures to those of the PedsQL™ 4.0 Generic Scales (PedsQL) from the PROMIS II nephrotic syndrome (NS) longitudinal cohort. Methods This was a prospective study in which 127 children (age range 8–17 years) with active NS from 14 centers were enrolled. Children with active NS defined as the presence of nephrotic range proteinuria (>2+ urinalysis and edema or urine protein/creatinine ratio >2 g/g) were eligible. Comparisons were made between children with prevalent (N=67) and incident (N=60) disease at the study enrollment visit. Results The PROMIS scores were worse in prevalent patients in the domains of peer relationship (p=0.01) and pain interference (p < 0.01). The PedsQL showed worse scores in prevalent patients for social functioning (p < 0.01) and school functioning (p = 0.03). Multivariable analyses showed that prevalent patients had worse scores in PROMIS pain interference (p=0.02) and PedsQL social functioning (p<0.01). Conclusion The PROMIS measures detected a significant impact of disease duration on HRQOL in children, such that peer relationships were worse and pain interfered with daily life to a greater degree among those with longer disease duration. These findings were in agreement with those for similar domains in the PedsQL legacy instrument.

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Background and objectives The Standardizing Care to Improve Outcomes in Pediatric ESRD Collaborative is a quality improvement initiative that aims to reduce peritoneal dialysis-associated infections in pediatric patients on chronic peritoneal dialysis. Our objectives were to determine whether provider compliance with peritoneal dialysis catheter care bundles was associated with lower risk for infection at the individual patient level and describe the epidemiology, risk factors, and outcomes for peritonitis in the Standardizing Care to Improve Outcomes in Pediatric ESRD Collaborative.Design, setting, participants, & measurements We collected peritoneal dialysis characteristics, causative organisms, compliance with care bundles, and outcomes in children with peritonitis between October of 2011 and September of 2014. Chi-squared tests, t tests, and generalized linear mixed models were used to assess risk factors for peritonitis.Results Of 734 children enrolled (54% boys; median age =9 years old; interquartile range, 1-15) from 29 centers, 391 peritonitis episodes occurred among 245 individuals over 10,130 catheter-months. The aggregate annualized peritonitis rate was 0.46 episodes per patient-year. Rates were highest among children #2 years old (0.62 episodes per patient-year). Gram-positive peritonitis predominated (37.8%) followed by culture-negative (24.7%), gramnegative (19.5%), and polymicrobial (10.3%) infections; fungal only peritonitis accounted for 7.7% of episodes. Compliance with the follow-up bundle was associated with a lower rate of peritonitis (rate ratio, 0.49; 95% confidence interval, 0.30 to 0.80) in the multivariable model. Upward orientation of the catheter exit site (rate ratio, 4.2; 95% confidence interval, 1.49 to 11.89) and touch contamination (rate ratio, 2.22; 95% confidence interval, 1.44 to 3.34) were also associated with a higher risk of peritonitis. Infection outcomes included resolution with antimicrobial treatment alone in 76.6%, permanent catheter removal in 12.2%, and catheter removal with return to peritoneal dialysis in 6% of episodes.Conclusions Lower compliance with standardized practices for follow-up peritoneal dialysis catheter care in the Standardizing Care to Improve Outcomes in Pediatric ESRD Collaborative was associated with higher risk of peritonitis. Quality improvement and prevention strategies have the potential to reduce peritoneal dialysisassociated peritonitis.

Children with an HR genotype in CKiD and NEPTUNE seem to have a more aggressive form of glomerular disease, in part due to a higher prevalence of focal segmental glomerulosclerosis. These consistent findings across independent cohorts suggest a common natural history for children with APOL1 -associated glomerular disease. Further study is needed to determine the generalizability of these findings.