Steroid-sensitive nephrotic syndrome (SSNS) accounts for .80% of cases of nephrotic syndrome in childhood. However, the etiology and pathogenesis of SSNS remain obscure. Hypothesizing that coding variation may underlie SSNS risk, we conducted an exome array association study of SSNS. We enrolled a discovery set of 363 persons (214 South Asian children with SSNS and 149 controls) and genotyped them using the Illumina HumanExome Beadchip. Four common single nucleotide polymorphisms (SNPs) in HLA-DQA1 and HLA-DQB1 (rs1129740, rs9273349, rs1071630, and rs1140343) were significantly associated with SSNS at or near the Bonferroni-adjusted P value for the number of single variants that were tested (odds ratio, 2.11; 95% confidence interval, 1.56 to 2.86; P=1.68310 26 (Fisher exact test). Two of these SNPs-the missense variants C34Y (rs1129740) and F41S (rs1071630) in HLA-DQA1-were replicated in an independent cohort of children of white European ancestry with SSNS (100 cases and #589 controls; P=1.42310 217). In the rare variant gene set-based analysis, the best signal was found in PLCG2 (P=7.825310 25). In conclusion, this exome array study identified HLA-DQA1 and PLCG2 missense coding variants as candidate loci for SSNS. The finding of a MHC class II locus underlying SSNS risk suggests a major role for immune response in the pathogenesis of SSNS.

We investigated angiotensin converting enzyme gene (ACE I/D) polymorphism as a risk for progressive renal damage in congenital uropathies. The ACE I/D genotype was determined in 196 Caucasian patients with congenital uropathies and 163 individuals with no clinical or sonographic evidence of any urological malformations. The study group included patients with ureteropelvic junction obstruction (n=49), primary obstructive megaureter (n=19), primary vesicoureteral reflux (VUR) (n=67), and posterior urethral valves (n=27). Thirty-four patients were excluded because of additional diseases or insufficient follow-up. There was no difference in the ACE I/D distribution between children with uropathies and normal controls (II 16%, ID 56%. DD 28% vs. II 26%, ID 50%, DD 24%). Renal lesions were found in 99 of 162 children by ultrasonography, intravenous pyelography, and nuclear scans. In these children there was significant over-representation of the DD genotype (II 11%, ID 53%, DD 36%) compared with normals (P<0.005, X2=14.9) or with patients with uropathies but no renal lesions (II 23%, ID 62%, DD 15%, P<0.005, X2=14.9). Because ACE I/D has been linked with progressive deterioration of renal function, we evaluated a subset of patients with initially normal kidneys who developed radiographic renal lesions (n=28). Among these patients there was an even greater over-representation of the DD genotype (II 0%, ID 43%, DD 57%, P<0.001, X2=22.6) compared with patients with uropathies but no radiographic lesions. Multivariate analysis revealed that the DD genotype is a risk factor for parenchymal destruction, which was independent of time of diagnosis, surgical intervention, or urinary tract infection. This finding was particularly relevant in patients with VUR who constituted the majority with initially normal kidneys who developed radiographic damage (22/28). Indeed, the odds ratio of developing parenchymal damage with VUR was significantly increased if the individual had the DD genotype (4.2, 95% confidence interval 1.4-13.0). In conclusion the ACE I/D gene polymorphism is a risk factor for renal parenchymal damage in patients with congenital urological abnormalities and appears particularly relevant in children with VUR, where it is an independent predisposing factor.

Objectives Our aim was to determine if chronic kidney disease (CKD) occurring in childhood impairs the normally vasoprotective functions of high-density lipoproteins (HDL). Materials and Methods HDL were isolated from children with end-stage renal disease on dialysis (ESRD), children with moderate CKD and controls with normal kidney function. Macrophage response to HDL was studied as expression of inflammatory markers (MCP-1, TNF-α, IL-1β) and chemotaxis. Human umbilical vein endothelial cells were used for expression of adhesion molecules (ICAM-1, VCAM-1, E-selectin) and adhesion. Cellular proliferation, apoptosis, and necrosis of endothelial cells was measured by MTS/PMS reagent-based assay, flow cytometry, and ELISA. Cholesterol efflux was assessed by gas chromatographic measurements of cholesterol in macrophages exposed to HDL. Results Compared with HDLControl, HDLCKD and HDLESRD heightened the cytokine response and disrupted macrophage chemotaxis. HDLControl reduced endothelial expression of ICAM-1, VCAM-1, E-selectin, whereas HDLCKD and HDLESRD were less effective and showed reduced capacity to protect endothelial cells against monocyte adhesion. Compared with a dramatically enhanced endothelial proliferation following injurious stimulus by HDLControl, neither HDLCKD nor HDLESRD caused proliferative effects. HDL of all three groups were equally protective against apoptosis assessed by flow cytometry and cleaved caspase-3 activity. Compared to HDLControl, HDLCKD and HDLESRD trended toward reduced capacity as cholesterol acceptors. Conclusion CKD in children impairs HDL function. Even in the absence of long-standing and concomitant risk factors, CKD alters specific HDL functions linked to control of inflammation and endothelial responses.

In the decade since the initial discovery and characterization of endothelin, its biology as a powerful vasoconstrictor has been dramatically demonstrated. Studies have clarified the existence of endothelin isoforms, complex mechanisms of biosynthesis, interaction with specific receptors, and pathogenic implications. We are on the brink of using endothelin antagonism as a clinical treatment for disease processes where endothelin plays an important role, including congestive heart failure and hypertension. Novel observations have been made about the unexpectedly profound contribution endothelins make to normal fetal maturation, especially in cardiac and enteric development.

HLA-DQA1 is a risk locus for SSNS, but not SRNS, in African American children, consistent with its role in SSNS risk in children of European, Asian, and African ancestries. There is little evidence of a significant role for the APOL1 high-risk alleles in childhood SSNS in African American children. Refinement of the HLA-DQA1 association identified the critical classic HLA antigen types and amino acids of the HLA-DQ α1 molecule.

The role of the endothelium is now known to encompass the generation of many potent cytokines which impact endothelial cells, adjacent tissue such as smooth muscle cells, and distant sites in an autocrine, paracrine, and endocrine manner, respectively. This review addresses two of these cytokines, nitric oxide and endothelin, and describes how each effects the functions of endothelial cells, including regulation of platelet aggregation and coagulation, regulation of vasomotor tone, modulation of inflammation, and the regulation of cellular proliferation. The emphasis is on the increasingly recognized importance of the autocrine and paracrine mechanisms by which nitric oxide and endothelin act. In particular, autoinduction of endothelin is proposed as a central mechanism underlying endothelin's renowned effects. Additionally, specific nitric oxide/endothelin interactions are discussed by which each cytokine modulates the production and actions of the other. The net effect observed in a variety of physiological and pathophysiological settings, therefore, reflects a balance of these opposing functions.

Background Shiga toxin–producing Escherichia coli (STEC) infections are leading causes of pediatric acute renal failure. Identifying hemolytic uremic syndrome (HUS) risk factors is needed to guide care. Methods We conducted a multicenter, historical cohort study to identify features associated with development of HUS (primary outcome) and need for renal replacement therapy (RRT) (secondary outcome) in STEC-infected children without HUS at initial presentation. Children aged &lt;18 years who submitted STEC-positive specimens between January 2011 and December 2015 at a participating study institution were eligible. Results Of 927 STEC-infected children, 41 (4.4%) had HUS at presentation; of the remaining 886, 126 (14.2%) developed HUS. Predictors (all shown as odds ratio [OR] with 95% confidence interval [CI]) of HUS included younger age (0.77 [.69–.85] per year), leukocyte count ≥13.0 × 103/μL (2.54 [1.42–4.54]), higher hematocrit (1.83 [1.21–2.77] per 5% increase) and serum creatinine (10.82 [1.49–78.69] per 1 mg/dL increase), platelet count &lt;250 × 103/μL (1.92 [1.02–3.60]), lower serum sodium (1.12 [1.02–1.23 per 1 mmol/L decrease), and intravenous fluid administration initiated ≥4 days following diarrhea onset (2.50 [1.14–5.46]). A longer interval from diarrhea onset to index visit was associated with reduced HUS risk (OR, 0.70 [95% CI, .54–.90]). RRT predictors (all shown as OR [95% CI]) included female sex (2.27 [1.14–4.50]), younger age (0.83 [.74–.92] per year), lower serum sodium (1.15 [1.04–1.27] per mmol/L decrease), higher leukocyte count ≥13.0 × 103/μL (2.35 [1.17–4.72]) and creatinine (7.75 [1.20–50.16] per 1 mg/dL increase) concentrations, and initial intravenous fluid administration ≥4 days following diarrhea onset (2.71 [1.18–6.21]). Conclusions The complex nature of STEC infection renders predicting its course a challenge. Risk factors we identified highlight the importance of avoiding dehydration and performing close clinical and laboratory monitoring.

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