Nutritional and Anthropometric Indices in Children Receiving Haemodiafiltration vs Conventional Haemodialysis - The HDF, Heart and Height (3H) Study.

BACKGROUND: The "HDF-Heart-Height" study showed that haemodiafiltration (HDF) is associated with improved growth compared to conventional haemodialysis (HD). We report a post-hoc analysis of this study assessing the effect of extracorporeal dialysis therapies on nutritional indices. METHODS: 107 children were included in the baseline cross-sectional analysis, of whom 79 (43 HD, 36 HDF) completed the 12-month follow-up. Height (Ht), optimal 'dry' weight (Wt), and body mass index (BMI) standard deviations scores (SDS), waist-to-hip ratio, des-acyl ghrelin (DAG), adiponectin, leptin, insulin-like growth factor-1 (IGF-1)-SDS and insulin were measured. RESULTS: The levels of nutritional indices were comparable between HDF and HD patients at baseline and 12-month. On univariable analyses Wt-SDS positively correlated with leptin and IGF-1-SDS, and negatively with DAG, while Ht-SDS of the overall cohort positively correlated with IGF1-SDS and inversely with DAG and adiponectin. On multivariable analyses, higher 12-month Ht-SDS was inversely associated with baseline DAG (beta = -0.13 per 500 higher; 95%CI -0.22, -0.04; P = .004). Higher Wt-SDS at 12-month was positively associated with HDF modality (beta = 0.47 vs HD; 95%CI 0.12-0.83; P = .01) and inversely with baseline DAG (beta = -0.18 per 500 higher; 95%CI -0.32, -0.05; P = .006). Growth Hormone (GH) treated patients receiving HDF had higher annualized increase in Ht SDS compared to those on HD. CONCLUSIONS: In children on HD and HDF both Wt- and Ht-SDS independently correlated with lower baseline levels of the anorexygenic hormone DAG. HDF may attenuate the resistance to GH, but further studies are required to examine the mechanisms linking HDF to improved growth.

Inactivation of Osteoblast PKC Signaling Reduces Cortical Bone Mass and Density and Aggravates Renal Osteodystrophy in Mice with Chronic Kidney Disease on High Phosphate Diet.

Chronic kidney disease (CKD) frequently leads to hyperphosphatemia and hyperparathyroidism, mineral bone disorder (CKD-MBD), ectopic calcifications and cardiovascular mortality. PTH activates the osteoanabolic Gαs/PKA and the Gαq/11/PKC pathways in osteoblasts, the specific impact of the latter in CKD-MBD is unknown. We generated osteoblast specific Gαq/11 knockout (KO) mice and established CKD-MBD by subtotal nephrectomy and dietary phosphate load. Bone morphology was assessed by micro-CT, osteoblast function by bone planar scintigraphy at week 10 and 22 and by histomorphometry. Osteoblasts isolated from Gαq/11 KO mice increased cAMP but not IP3 in response to PTH 1-34, demonstrating the specific KO of the PKC signaling pathway. Osteoblast specific Gαq/11 KO mice exhibited increased serum calcium and reduced bone cortical thickness and mineral density at 24 weeks. CKD Gαq/11 KO mice had similar bone morphology compared to WT, while CKD Gαq/11-KO on high phosphate diet developed decreased metaphyseal and diaphyseal cortical thickness and area, as well as a reduction in trabecular number. Gαq/11-KO increased bone scintigraphic tracer uptake at week 10 and mitigated tracer uptake in CKD mice at week 22. Histological bone parameters indicated similar trends. Gαq/11-KO in osteoblast modulates calcium homeostasis, bone formation rate, bone morphometry, and bone mineral density. In CKD and high dietary phosphate intake, osteoblast Gαq/11/PKC KO further aggravates mineral bone disease.

Hemodiafiltration maintains a sustained improvement in blood pressure compared to conventional hemodialysis in children-the HDF, heart and height (3H) study.

BACKGROUND: Hypertension is prevalent in children on dialysis and associated with cardiovascular disease. We studied the blood pressure (BP) trends and the evolution of BP over 1 year in children on conventional hemodialysis (HD) vs. hemodiafiltration (HDF). METHODS: This is a post hoc analysis of the "3H - HDF-Hearts-Height" dataset, a multicenter, parallel-arm observational study. Seventy-eight children on HD and 55 on HDF who had three 24-h ambulatory BP monitoring (ABPM) measures over 1 year were included. Mean arterial pressure (MAP) was calculated and hypertension defined as 24-h MAP standard deviation score (SDS) ≥95th percentile. RESULTS: Poor agreement between pre-dialysis systolic BP-SDS and 24-h MAP was found (mean difference - 0.6; 95% limits of agreement -4.9-3.8). At baseline, 82% on HD and 44% on HDF were hypertensive, with uncontrolled hypertension in 88% vs. 25% respectively; p < 0.001. At 12 months, children on HDF had consistently lower MAP-SDS compared to those on HD (p < 0.001). Over 1-year follow-up, the HD group had mean MAP-SDS increase of +0.98 (95%CI 0.77-1.20; p < 0.0001), whereas the HDF group had a non-significant increase of +0.15 (95%CI -0.10-0.40; p = 0.23). Significant predictors of MAP-SDS were dialysis modality (ß = +0.83 [95%CI +0.51 - +1.15] HD vs. HDF, p < 0.0001) and higher inter-dialytic-weight-gain (IDWG)% (ß = 0.13 [95%CI 0.06-0.19]; p = 0.0003). CONCLUSIONS: Children on HD had a significant and sustained increase in BP over 1 year compared to a stable BP in those on HDF, despite an equivalent dialysis dose. Higher IDWG% was associated with higher 24-h MAP-SDS in both groups.

Influenza and pneumococcus vaccination rates in pediatric dialysis patients in Europe: recommendations vs reality A European Pediatric Dialysis Working Group and European Society for Pediatric Nephrology Dialysis Working Group study

Background/aim: Children on dialysis are under increased risk of influenza and invasive pneumococcal disease. Although vaccination against these microorganisms are recommended in dialysis patients and despite the fact that these vaccines can reduce disease burden and rates of hospitalization due to infection, vaccination rates are below expected and desired. We aimed to evaluate influenza and pneumococcal vaccination and infection rates in European pediatric dialysis centers. Materials and methods: In 16 centers from 11 countries, 357 pediatric dialysis patients were evaluated retrospectively during 1 year of observation period between 01.01.2014 and 01.01.2015. Results: In all centers, vaccination policy included immunization of dialysis patients with inactive influenza vaccine and pneumococcal conjugate vaccine (PCV). Fifty percent of the centers recommended pneumococcal polysaccharide vaccine following routine PCV series. A significantly higher pneumococcal vaccination rate (43.9%) was seen in peritoneal dialysis (PD) patients compared to those on hemodialysis (HD) (32.9%) (p = 0.035), while the rates for influenza were similar (42.4% and 46.1% respectively, p = 0.496). Among all dialysis patients, 2.2% (n = 8) developed pneumonia and 6.4% (n = 23) was infected by Influenza. Pneumococcic pneumonia rate was 5% for 140 patients who received antipneumococcal vaccine, while only one pneumonia episode was recorded out of 217 unvaccinated patients (p = 0.007). The influenza virus infection rates were similar for patients vaccinated and nonvaccinated (7 % and 6 %, respectively). Conclusions: Although influenza and pneumococcal vaccines are highly recommended in pediatric dialysis patients, vaccination rates were lower than expected. Pneumococcal vaccination rates were higher in PD compared to the patients on HD. The rate of children with influenza infection was higher than pneumonia. The efficacy of influenza and pneumococcal vaccines was highlighted by the low infection rates. Higher pneumonia rates in patients vaccinated against pneumococcus compared to unvaccinated ones might be due to coexisting risk factors.

Haemodiafiltration does not lower protein-bound uraemic toxin levels compared with haemodialysis in a paediatric population.

BACKGROUND: Haemodiafiltration (HDF) is accepted to effectively lower plasma levels of middle molecules in the long term, while data are conflicting with respect to the additive effect of convection on lowering protein-bound uraemic toxins (PBUTs). Here we compared pre-dialysis ß2-microglobulin (ß2M) and PBUT levels and the percentage of protein binding (%PB) in children on post-dilution HDF versus conventional high- (hf) or low-flux (lf) haemodialysis (HD) over 12 months of treatment. METHODS: In a prospective multicentre, non-randomized parallel-arm intervention study, pre-dialysis levels of six PBUTs and ß2M were measured in children (5-20 years) on post-HDF (n = 37), hf-HD (n = 42) and lf-HD (n = 18) at baseline and after 12 months. Analysis of variance was used to compare levels and %PB in post-HDF versus conventional hf-HD and lf-HD cross-sectionally at 12 months and longitudinal from baseline to 12 months. RESULTS: For none of the PBUTs, no difference was found in either total and free plasma levels or %PB between post-HDF versus the hf-HD and lf-HD groups. Children treated with post-HDF had lower pre-dialysis ß2M levels [median 23.2 (21.5; 26.6) mg/dL] after 12 months versus children on hf-HD [P<0.01; 35.2 (29.3; 41.2) mg/dL] and children on lf-HD [P<0.001; 47.2 (34.3; 53.0) mg/dL]. While ß2M levels remained steady in the hf-HD and lf-HD group, a decrease in ß2M was demonstrated for children on post-HDF (P<0.01). CONCLUSIONS: While post-HDF successfully decreased ß2M, no additive effect on PBUT over 12 months of treatment was found. PBUT removal is complex and hampered by several factors. In children, these factors might be different from adults and should be explored in future research.

Effects of Hemodiafiltration versus Conventional Hemodialysis in Children with ESKD: The HDF, Heart and Height Study.

BACKGROUND: Hypertension and cardiovascular disease are common in children undergoing dialysis. Studies suggest that hemodiafiltration (HDF) may reduce cardiovascular mortality in adults, but data for children are scarce. METHODS: The HDF, Heart and Height study is a nonrandomized observational study comparing outcomes on conventional hemodialysis (HD) versus postdilution online HDF in children. Primary outcome measures were annualized changes in carotid intima-media thickness (cIMT) SD score and height SD score. RESULTS: We enrolled 190 children from 28 centers; 78 on HD and 55 on HDF completed 1-year follow-up. The groups were comparable for age, dialysis vintage, access type, dialysis frequency, blood flow, and residual renal function. At 1 year, cIMT SD score increased significantly in children on HD but remained static in the HDF cohort. On propensity score analysis, HD was associated with a +0.47 higher annualized cIMT SD score compared with HDF. Height SD score increased in HDF but remained static in HD. Mean arterial pressure SD score increased with HD only. Factors associated with higher cIMT and mean arterial pressure SD-scores were HD group, higher ultrafiltration rate, and higher ß2-microglobulin. The HDF cohort had lower ß2-microglobulin, parathyroid hormone, and high-sensitivity C-reactive protein at 1 year; fewer headaches, dizziness, or cramps; and shorter postdialysis recovery time. CONCLUSIONS: HDF is associated with a lack of progression in vascular measures versus progression with HD, as well as an increase in height not seen in the HD cohort. Patient-related outcomes improved among children on HDF correlating with improved BP control and clearances. Confirmation through randomized trials is required.

Development and initial validation of the MS score for diagnosis of macrophage activation syndrome in systemic juvenile idiopathic arthritis.

OBJECTIVE: To develop and validate a diagnostic score that aids in identifying macrophage activation syndrome (MAS) in patients with systemic juvenile idiopathic arthritis (sJIA). METHODS: The clinical and laboratory features of 362 patients with sJIA-associated MAS and 404 patients with active sJIA without evidence of MAS were collected in a multinational collaborative project. Eighty percent of the study population was used to develop the score and the remaining 20% constituted the validation sample. A Bayesian Model Averaging approach was used to assess the role of each clinical and laboratory variables in the diagnosis of MAS and to obtain the coefficients of selected variables. The final score, named MAS/sJIA (MS) score, resulted from the linear combination of these coefficients multiplied by the values of each variable. The cut-off that best discriminated MAS from active sJIA was calculated by means of receiver operating characteristic (ROC) curve analysis. Score performance was evaluated in both developmental and validation samples. RESULTS: The MS score ranges from -8.4 to 41.8 and comprises seven variables: central nervous system dysfunction, haemorrhagic manifestations, active arthritis, platelet count, fibrinogen, lactate dehydrogenase and ferritin. A cut-off value ≥-2.1 revealed the best performance in discriminating MAS from active sJIA, with a sensitivity of 0.85, a specificity of 0.95 and a kappa value of 0.80. The good performance of the MS score was confirmed in the validation sample. CONCLUSION: The MS score is a powerful and feasible tool that may assist practitioners in making a timely diagnosis of MAS in patients with sJIA.

Canakinumab in patients with systemic juvenile idiopathic arthritis and active systemic features: results from the 5-year long-term extension of the phase III pivotal trials.

OBJECTIVES: To evaluate the long-term efficacy and safety of canakinumab in patients with active systemic juvenile idiopathic arthritis (JIA). METHODS: Patients (2-19 years) entered two phase III studies and continued in the long-term extension (LTE) study. Efficacy assessments were performed every 3 months, including adapted JIA American College of Rheumatology (aJIA-ACR) criteria, Juvenile Arthritis Disease Activity Score (JADAS) and ACR clinical remission on medication criteria (CRACR). Efficacy analyses are reported as per the intent-to-treat population. RESULTS: 144 of the 177 patients (81%) enrolled in the core study entered the LTE. Overall, 75 patients (42%) completed and 102 (58%) discontinued mainly for inefficacy (63/102, 62%), with higher discontinuation rates noted in the late responders group (n=25/31, 81%) versus early responders (n=11/38, 29%). At 2 years, aJIA-ACR 50/70/90 response rates were 62%, 61% and 54%, respectively. CRACR was achieved by 20% of patients at month 6; 32% at 2 years. A JADAS low disease activity score was achieved by 49% of patients at 2 years. Efficacy results were maintained up to 5 years. Of the 128/177 (72.3%) patients on glucocorticoids, 20 (15.6%) discontinued and 28 (22%) tapered to 0.150 mg/kg/day. Seven patients discontinued canakinumab due to CR. There were 13 macrophage activation syndrome (three previously reported) and no additional deaths (three previously reported). No new safety findings were observed. CONCLUSION: Response to canakinumab treatment was sustained and associated with substantial glucocorticoid dose reduction or discontinuation and a relatively low retention-on-treatment rate. No new safety findings were observed on long-term use of canakinumab. TRIAL REGISTRATION NUMBERS: NCT00886769, NCT00889863, NCT00426218 and NCT00891046.

Clinical and genetic heterogeneity in familial steroid-sensitive nephrotic syndrome.

BACKGROUND: Familial steroid-sensitive nephrotic syndrome (SSNS) is a rare condition. The disease pathophysiology remains elusive. However, bi-allelic mutations in the EMP2 gene were identified, and specific variations in HLA-DQA1 were linked to a high risk of developing the disease. METHODS: Clinical data were analyzed in 59 SSNS families. EMP2 gene was sequenced in families with a potential autosomal recessive (AR) inheritance. Exome sequencing was performed in a subset of 13 families with potential AR inheritance. Two variations in HLA-DQA1 were genotyped in the whole cohort. RESULTS: Transmission was compatible with an AR (n = 33) or autosomal dominant (AD, n = 26) inheritance, assuming that familial SSNS is a monogenic trait. Clinical features did not differ between AR and AD groups. All patients, including primary (n = 7) and secondary steroid resistant nephrotic syndrone (SRNS), (n = 13) were sensitive to additional immunosuppressive therapy. Both HLA-DQA1 variations were found to be highly linked to the disease (OR = 4.34 and OR = 4.89; p < 0.001). Exome sequencing did not reveal any pathogenic mutation, neither did EMP2 sequencing. CONCLUSIONS: Taken together, these results highlight the clinical and genetic heterogeneity in familial SSNS. Clinical findings sustain an immune origin in all patients, whatever the initial steroid-sensitivity. The absence of a variant shared by two families and the HLA-DQA1 variation enrichments suggest a complex mode of inheritance.

Effect of haemodiafiltration vs conventional haemodialysis on growth and cardiovascular outcomes in children - the HDF, heart and height (3H) study.

BACKGROUND: Cardiovascular disease is prevalent in children on dialysis and accounts for almost 30% of all deaths. Randomised trials in adults suggest that haemodiafiltration (HDF) with high convection volumes is associated with reduced cardiovascular mortality compared to high-flux haemodialysis (HD); however paediatric data are scarce. We designed the haemodiafiltration, heart and height (3H) study to test the hypothesis that children on HDF have an improved cardiovascular risk profile, growth and nutritional status and quality of life, compared to those on conventional HD. We performed a non-randomised parallel-arm intervention study within the International Paediatric Haemodialysis Network Registry comparing children on HDF and conventional HD to determine annualised change in cardiovascular end-points and growth. Here we present the 3H study design and baseline characteristics of the study population. METHODS: 190 children were screened and 177 (106 on HD and 71 on HDF) recruited from 28 centres in 10 countries. There was no difference in age, underlying diagnosis, comorbidities, previous dialysis therapy, dialysis vintage, residual renal function, type of vascular access or blood flow between HD and HDF groups. High flux dialysers were used in 63% of HD patients and ultra-pure water was available in 52%. HDF patients achieved a median convection volume of 13.3 L/m2; this was associated with the blood flow rate only ((p = 0.0004, r = 0.42) and independent of access type (p = 0.38). DISCUSSION: This is the largest study on dialysis outcomes in children that involves deep phenotyping across a wide range of cardiovascular, anthropometric, nutritional and health-related quality of life measures, to test the hypothesis that HDF leads to improved cardiovascular and growth outcomes compared to conventional HD. TRIAL REGISTRATION: ClinicalTrials.gov: NCT02063776 . The trial was prospectively registered on the 14 Feb 2014.

Biomarker research to improve clinical outcomes of peritoneal dialysis: consensus of the European Training and Research in Peritoneal Dialysis (EuTRiPD) network.

Peritoneal dialysis (PD) therapy substantially requires biomarkers as tools to identify patients who are at the highest risk for PD-related complications and to guide personalized interventions that may improve clinical outcome in the individual patient. In this consensus article, members of the European Training and Research in Peritoneal Dialysis Network (EuTRiPD) review the current status of biomarker research in PD and suggest a selection of biomarkers that can be relevant to the care of PD patients and that are directly accessible in PD effluents. Currently used biomarkers such as interleukin-6, interleukin-8, ex vivo-stimulated interleukin-6 release, cancer antigen-125, and advanced oxidation protein products that were collected through a Delphi procedure were first triaged for inclusion as surrogate endpoints in a clinical trial. Next, novel biomarkers were selected as promising candidates for proof-of-concept studies and were differentiated into inflammation signatures (including interleukin-17, M1/M2 macrophages, and regulatory T cell/T helper 17), mesothelial-to-mesenchymal transition signatures (including microRNA-21 and microRNA-31), and signatures for senescence and inadequate cellular stress responses. Finally, the need for defining pathogen-specific immune fingerprints and phenotype-associated molecular signatures utilizing effluents from the clinical cohorts of PD patients and "omics" technologies and bioinformatics-biostatistics in future joint-research efforts was expressed. Biomarker research in PD offers the potential to develop valuable tools for improving patient management. However, for all biomarkers discussed in this consensus article, the association of biological rationales with relevant clinical outcomes remains to be rigorously validated in adequately powered, prospective, independent clinical studies.

C5 nephritic factors drive the biological phenotype of C3 glomerulopathies.

C3 Glomerulopathies, which include Dense Deposit Disease and C3 Glomerulonephritis, are associated with genetic and acquired dysregulation of the C3 convertase alternative pathway of complement. The potential role of the activation of the C5 convertase has not been studied extensively. Here we analyzed IgG samples from patients with C3 Glomerulopathies to identify circulating autoantibodies that stabilize the C3 alternative pathway (C3 Nephritic Factors) as well as C5 convertases (C5 Nephritic Factors), thus preventing decay of these enzyme complexes. Rare variants in alternative pathway genes were found in 28 of 120 tested patients. C3 and C5 Nephritic Factors were found in 76 of 101 (75%) and 29 of 59 (49%) of the patients, respectively. Therefore, we compared the results of the assays for the C3 and C5 nephritic factors functional activity: 29% were positive for C3 Nephritic Factors alone, 39% were positive for both C3 and C5 Nephritic Factors, and 10% were positive for C5 Nephritic Factors alone. We found that the addition of properdin-enhanced stabilization of C3 convertase in the presence of IgG doubly positive for both Nephritic Factors, while it did not modify the stabilization mediated by IgG solely positive for C3 Nephritic Factors. Both C3 and C5 Nephritic Factors correlated with C3 consumption, while only C5 Nephritic Factors correlated with sC5b9 levels. C5 Nephritic Factors-positive patients were more likely to have C3 Glomerulonephritis than Dense Deposit Disease. Thus, dysregulation of the C5 convertase contributes to C3 Glomerulopathies inter-disease differences and may have direct therapeutic implications.

Prednisone versus prednisone plus ciclosporin versus prednisone plus methotrexate in new-onset juvenile dermatomyositis: a randomised trial.

BACKGROUND: Most data for treatment of dermatomyositis and juvenile dermatomyositis are from anecdotal, non-randomised case series. We aimed to compare, in a randomised trial, the efficacy and safety of prednisone alone with that of prednisone plus either methotrexate or ciclosporin in children with new-onset juvenile dermatomyositis. METHODS: We did a randomised trial at 54 centres in 22 countries. We enrolled patients aged 18 years or younger with new-onset juvenile dermatomyositis who had received no previous treatment and did not have cutaneous or gastrointestinal ulceration. We randomly allocated 139 patients via a computer-based system to prednisone alone or in combination with either ciclosporin or methotrexate. We did not mask patients or investigators to treatment assignments. Our primary outcomes were the proportion of patients achieving a juvenile dermatomyositis PRINTO 20 level of improvement (20% improvement in three of six core set variables at 6 months), time to clinical remission, and time to treatment failure. We compared the three treatment groups with the Kruskal-Wallis test and Friedman's test, and we analysed survival with Kaplan-Meier curves and the log-rank test. Analysis was by intention to treat. Here, we present results after at least 2 years of treatment (induction and maintenance phases). This trial is registered with ClinicalTrials.gov, number NCT00323960. FINDINGS: Between May 31, 2006, and Nov 12, 2010, 47 patients were randomly assigned prednisone alone, 46 were allocated prednisone plus ciclosporin, and 46 were randomised prednisone plus methotrexate. Median duration of follow-up was 35.5 months. At month 6, 24 (51%) of 47 patients assigned prednisone, 32 (70%) of 46 allocated prednisone plus ciclosporin, and 33 (72%) of 46 administered prednisone plus methotrexate achieved a juvenile dermatomyositis PRINTO 20 improvement (p=0.0228). Median time to clinical remission was 41.9 months in patients assigned prednisone plus methotrexate but was not observable in the other two treatment groups (2.45 fold [95% CI 1.2-5.0] increase with prednisone plus methotrexate; p=0.012). Median time to treatment failure was 16.7 months in patients allocated prednisone, 53.3 months in those assigned prednisone plus ciclosporin, but was not observable in patients randomised to prednisone plus methotrexate (1.95 fold [95% CI 1.20-3.15] increase with prednisone; p=0.009). Median time to prednisone discontinuation was 35.8 months with prednisone alone compared with 29.4-29.7 months in the combination groups (p=0.002). A significantly greater proportion of patients assigned prednisone plus ciclosporin had adverse events, affecting the skin and subcutaneous tissues, gastrointestinal system, and general disorders. Infections and infestations were significantly increased in patients assigned prednisone plus ciclosporin and prednisone plus methotrexate. No patients died during the study. INTERPRETATION: Combined treatment with prednisone and either ciclosporin or methotrexate was more effective than prednisone alone. The safety profile and steroid-sparing effect favoured the combination of prednisone plus methotrexate. FUNDING: Italian Agency of Drug Evaluation, Istituto Giannina Gaslini (Genoa, Italy), Myositis Association (USA).

Should sodium removal in peritoneal dialysis be estimated from the ultrafiltration volume?

In peritoneal dialysis (PD), ultrafiltration (UF) volume is the sum of solute-free- and solute-coupled-water removal, a dynamic process throughout the entire dwell exerted via aquaporin-1 (AQP1) and small pores, respectively. Determination of sodium sieving is used as a parameter for AQP1 function analysis, while coupled water removal is essential for adequate sodium and water balance and thus blood pressure control. The diffusive capacity of glucose via the small pores determines the dynamic crystalloid osmotic gradient. The osmotic conductance, i.e., milliliter of UF per gram of glucose absorbed, quantifies cooperation between small-pores and AQP1 channels. In continuous ambulatory peritoneal dialysis, with dwell times beyond glucose-induced sodium-sieving effects, approximate dialytic sodium removal (DSR) may be estimated from the UF volume (in average 100 mmol Na/L UF), while DSR is lower, with shorter cycle times, in automated PD (APD); therefore, effluent sodium concentrations should be measured. Applying dialysis mechanics, i.e., varying dwell time and dwell volume-as proposed in adapted APD to the PD prescription-may provide unmatched high DSR relative to UF volume, findings which are not sufficiently explained by the three-pore model of PD. Overall DSR should therefore be measured rather than estimated from UF volume.

Effect of center practices on the choice of the first dialysis modality for children and young adults.

BACKGROUND: Peritoneal dialysis (PD) remains the modality of choice in children, but there is no clear evidence to support a better outcome in children treated with PD. We aimed to assess factors that have an impact on the choice of dialysis modality in children and young adults in France and sought to determine the roles of medical factors and center practices. METHODS: We included all patients aged <20 years at the start of renal replacement therapy (RRT), recorded in the French RRT Registry between 2002 and 2013. Hierarchical logistic regression models were used to study the association between the patient/center characteristics and the probability of receiving PD as the first dialysis modality. RESULTS: We included 806 patients starting RRT in 177 centers, 23 of which were specialized pediatric centers. Six hundred and one patients (74.6 %) started with hemodialysis (HD), whereas 205 (25.4 %) started with PD. A greater probability of PD was found in younger children, whereas starting the treatment in an emergency setting was associated with a low use of PD. We found a significant variability among centers that accounted for 43 % of the total variability. The probability of PD was higher in adult centers and was proportional to the rate of PD in the center. CONCLUSIONS: Center practices are a major factor in the choice of dialysis modality. This raises concerns about patient and family choices and to what extent doctors may influence the final decision. Further pediatric studies focusing on children's and parents' wishes are needed to provide care as close as possible to patients' and families' expectations.

Worldwide view of nephropathic cystinosis: results from a survey from 30 countries.

BACKGROUND: Nephropathic cystinosis is a rare inherited metabolic disorder leading to progressive renal failure and extra-renal comorbidity. The prognosis relies on early adherence to cysteamine treatment and symptomatic therapies. Developing nations [DiN] experience many challenges for management of cystinosis. The aim of this study was to assess the management characteristics in DiN compared with developed nations [DeN]. METHODS: A questionnaire was sent between April 2010 and May 2011 to 87 members of the International Pediatric Nephrology Association, in 50 countries. RESULTS: A total of 213 patients were included from 41 centres in 30 nations (109 from 17 DiN and 104 from 13 DeN). 7% of DiN patients died at a median age of 5 years whereas no death was observed in DeN. DiN patients were older at the time of diagnosis. In DiN, leukocyte cystine measurement was only available in selected cases for diagnosis but never for continuous monitoring. More patients had reached end-stage renal disease in DiN (53.2 vs. 37.9%, p = 0.03), within a shorter time of evolution (8 vs. 10 yrs., p = 0.0008). The earlier the cysteamine treatment, the better the renal outcome, since the median renal survival increased up to 16.1 [12.5-/] yrs. in patients from DeN treated before the age of 2.5 years of age (p = 0.0001). However, the renal survival was not statistically different between DeN and DiN when patients initiated cysteamine after 2.5 years of age. The number of transplantations and the time from onset of ESRD to transplantation were not different in DeN and DiN. More patients were kept under maintenance dialysis in DiN (26% vs.19%, p = 0.02); 79% of patients from DiN vs. 45% in DeN underwent peritoneal dialysis. CONCLUSIONS: Major discrepancies between DiN and DeN in the management of nephropathic cystinosis remain a current concern for many patients living in countries with limited financial resources.

Comprehensive PKD1 and PKD2 Mutation Analysis in Prenatal Autosomal Dominant Polycystic Kidney Disease.

Prenatal forms of autosomal dominant polycystic kidney disease (ADPKD) are rare but can be recurrent in some families, suggesting a common genetic modifying background. Few patients have been reported carrying, in addition to the familial mutation, variation(s) in polycystic kidney disease 1 (PKD1) or HNF1 homeobox B (HNF1B), inherited from the unaffected parent, or biallelic polycystic kidney and hepatic disease 1 (PKHD1) mutations. To assess the frequency of additional variations in PKD1, PKD2, HNF1B, and PKHD1 associated with the familial PKD mutation in early ADPKD, these four genes were screened in 42 patients with early ADPKD in 41 families. Two patients were associated with de novo PKD1 mutations. Forty patients occurred in 39 families with known ADPKD and were associated with PKD1 mutation in 36 families and with PKD2 mutation in two families (no mutation identified in one family). Additional PKD variation(s) (inherited from the unaffected parent when tested) were identified in 15 of 42 patients (37.2%), whereas these variations were observed in 25 of 174 (14.4%, P=0.001) patients with adult ADPKD. No HNF1B variations or PKHD1 biallelic mutations were identified. These results suggest that, at least in some patients, the severity of the cystic disease is inversely correlated with the level of polycystin 1 function.

Increasing sodium removal on peritoneal dialysis: applying dialysis mechanics to the peritoneal dialysis prescription.

Optimal fluid removal on peritoneal dialysis (PD) requires removal of water coupled with sodium, which is predominantly achieved via the small pores in the peritoneal membrane. On the other hand, free-water transport takes place through aquaporin-1 channels, but leads to sodium retention and over hydration. PD prescription can be adapted to promote small pore transport to achieve improved sodium and fluid management. Both adequate dwell volume and dwell time are required for small pore transport. The dwell volume determines the amount of "wetted" peritoneal membrane being increased in the supine position and optimized at dwell volumes of approximately 1400 ml/m(2). Diffusion across the recruited small pores is time-dependent, favored by a long dwell time, and driven by the transmembrane solute gradient. According to the 3-pore model of conventional PD, sodium removal primarily occurs via convection. The clinical application of these principles is essential for optimal performance of PD and has resulted in a new approach to the automated PD prescription: adapted automated PD. In adapted automated PD, sequential short- and longer-dwell exchanges, with small and large dwell volumes, respectively, are used. A crossover trial in adults and a pilot study in children suggests that sodium and fluid removal are increased by adapted automated PD, leading to improved blood pressure control when compared with conventional PD. These findings are not explained by the current 3-pore model of peritoneal permeability and require further prospective crossover studies in adults and children for validation.

Observations of a large Dent disease cohort.

Dent disease classically combines low-molecular-weight proteinuria, hypercalciuria with nephrocalcinosis, and renal failure. Nephrotic range proteinuria, normal calciuria, and hypokalemia have been rarely reported. It is unknown whether the changes in phenotype observed over time are explained by a decrease in glomerular filtration rate (GFR) or whether there is any phenotype-genotype relationship. To answer this we retrospectively analyzed data from 109 male patients with CLCN5 mutations (Dent-1) and 9 patients with mutation of the OCRL gene (Dent-2). In Dent-1 disease, the estimated GFR decreased with age, by 1.0 to 1.6 ml/min per 1.73 m(2)/yr in the absence and presence of nephrocalcinosis, respectively, with no significant difference. Median values of low-molecular-weight proteinuria were in the nephrotic range and remained at the same level even in late renal disease. End-stage renal disease occurred in 12 patients, at a median age of 40 years. Hypercalciuria decreased with glomerular filtration and was absent in 40% of the patients under 30 and 85% of those over the age of 30. Hypophosphatemia did not resolve with age and calcitriol concentrations were in the upper normal range. Kalemia decreased with age, with half of the patients over the age of 18 presenting with hypokalemia. Thus, no phenotype/genotype correlation was observed in this cohort of patients with Dent disease.

CFH gene mutation in a case of Shiga toxin-associated hemolytic uremic syndrome (STEC-HUS).

BACKGROUND: We report the case of a patient with Shiga toxin (Stx)-associated hemolytic-uremic syndrome (HUS) (STEC-HUS) with a concomitant heterozygous mutation of the gene coding for complement Factor H (CFH). CASE DIAGNOSIS/TREATMENT: An 18-month-old patient presented with hemolytic anemia and thrombotic microangiopathy in the context of acute gastroenteritis. While the patient did not show kidney or other organ failure, he had persistent hemolysis and complement 3 activation (low C3), leading to the decision to commence immunotherapy with eculizumab (Soliris®) together with transient antibiotic coverage and meningococcal vaccination. Patient outcome was favorable. Diagnostic work-up identified Escherichia coli-associated Type 2 Shiga toxin. Complement analysis showed a heterozygous mutation of the CFH gene (c.2103 G>A, p. Trp701X) resulting in a quantitative CFH defect. CONCLUSIONS: We report a case of STEC-HUS with a quantitative CFH defect caused by a mutation of the CFH gene. To the best of our knowledge, very few cases of STEC-HUS with complement gene mutation have been reported, but none to date with a CFH mutation. We therefore suggest that complement analyses be performed in patients diagnosed with STEC-HUS in association with low C3 levels, especially in patients presenting with severe or unexpected clinical symptoms.