Real-world evidence on the dosing and safety of C.E.R.A. in pediatric dialysis patients: findings from the International Pediatric Dialysis Network registries

BACKGROUND

This retrospective real-world study used data from two registries, International Pediatric Peritoneal Dialysis Network (IPPN) and International Pediatric Hemodialysis Network (IPHN), to characterize the efficacy and safety of continuous erythropoietin receptor activator (C.E.R.A.) in pediatric patients with chronic kidney disease (CKD) on peritoneal dialysis (PD) or hemodialysis (HD).

METHODS

IPPN and IPHN collect prospective data (baseline and every 6 months) from pediatric PD and HD centers worldwide. Demographics, clinical characteristics, dialysis information, treatment, laboratory parameters, number and causes of hospitalization events, and deaths were extracted for patients on C.E.R.A. treatment (IPPN: 2007-2021; IPHN: 2013-2021).

RESULTS

We analyzed 177 patients on PD (median age 10.6 years) and 52 patients on HD (median age 14.1 years) who had ≥ 1 observation while being treated with C.E.R.A. The median (interquartile range [IQR]) observation time under C.E.R.A. exposure was 6 (0-12.5) and 12 (0-18) months, respectively. Hemoglobin concentrations were stable over time; respective means (standard deviation) at last observation were 10.9 (1.7) g/dL and 10.4 (1.7) g/dL. Respective median (IQR) monthly C.E.R.A. doses at last observation were 3.5 (2.3-5.1) µg/kg, or 95 (62-145) µg/m2 and 2.1 (1.2-3.4) µg/kg, or 63 (40-98) µg/m2. Non-elective hospitalizations occurred in 102 (58%) PD and 32 (62%) HD patients. Seven deaths occurred (19.8 deaths per 1000 observation years).

CONCLUSIONS

C.E.R.A. was associated with efficient maintenance of hemoglobin concentrations in pediatric patients with CKD on dialysis, and appeared to have a favorable safety profile. The current analysis revealed no safety signals.

Lessons learned from regional training of paediatric nephrology fellows in Africa

BACKGROUND

Access to care for children with kidney disease is limited in less well-resourced regions of the world and paediatric nephrology (PN) workforce development with good practical skills is critical.

METHODS

Retrospective review of a PN training program and trainee feedback from 1999 to 2021, based at Red Cross War Memorial Children's Hospital (RCWMCH), University of Cape Town.

RESULTS

A regionally appropriate 1-2-year training program enrolled 38 fellows with an initial 100% return rate to their country of origin. Program funding included fellowships from the International Pediatric Nephrology Association (IPNA), International Society of Nephrology (ISN), International Society of Peritoneal Dialysis (ISPD), and the African Paediatric Fellowship Program (APFP). Fellows were trained on both in- and out-patient management of infants and children with kidney disorders. "Hands-on skills" training included examination, diagnosis and management skills, practical insertion of peritoneal dialysis catheters for management of acute kidney injury and kidney biopsies. Of 16 trainees who completed > 1 year of training, 14 (88%) successfully completed subspecialty exams and 9 (56%) completed a master's degree with a research component. PN fellows reported that their training was appropriate and enabled them to make a difference in their respective communities.

CONCLUSIONS

This training program has successfully equipped African physicians with the requisite knowledge and skills to provide PN services in resource-constrained areas for children with kidney disease. The provision of funding from multiple organizations committed to paediatric kidney disease has contributed to the success of the program, along with the fellows' commitment to build PN healthcare capacity in Africa. A higher resolution version of the Graphical abstract is available as Supplementary information.

HUS with mutations in CFH and STEC infection treated with eculizumab in a 4-year-old girl

BACKGROUND

Hemolytic uremic syndrome secondary to Shiga-toxin-producing Escherichia coli infection (STEC-HUS) generally shows a favorable outcome. Few cases develop extra-renal complications, since neurological involvement is an important cause of morbidity and mortality. The role of complement in STEC-HUS has been recently highlighted, and the use of eculizumab in severe cases has been communicated. HUS results from environmental and genetic factors, but the simultaneous occurrence of STEC and complement mutations remains undetermined.

METHODS

A pediatric case with severe STEC-HUS carrying CFH mutations, with favorable response to eculizumab is analyzed.

RESULTS

STEC-HUS was diagnosed in a 4-year-old girl with classic HUS, including low C3. Peritoneal dialysis was started due to hypertension, oligoanuria, and pleural effusion. She evolved with generalized tonic-clonic seizures and required mechanical ventilation. MRI reported multiple supra- and infratentorial ischemic lesions with laminar/striatal cortical necrosis and leukoencephalopathy. After two eculizumab doses, a significative stabilization in diuresis, blood pressure, creatinine, and C3 was achieved. At the third week, episodes of massive digestive bleeding and a life-threatening condition required a colectomy thus preserving the ileocecal valve. Due to atypical evolution, a genetic study was considered, identifying two heterozygous variants (CFH S1191L/V1197A).

CONCLUSION

STEC-HUS in patients with a genetic predisposition has been previously reported, but the low frequency of occurrence makes it a rare disease. As in the present case, patients with atypical course might benefit from genetic analysis to evaluate early eculizumab initiation and to better understand its phenotype. A higher resolution version of the Graphical abstract is available as Supplementary information.

IPNA clinical practice recommendations for the diagnosis and management of children with steroid-sensitive nephrotic syndrome

Idiopathic nephrotic syndrome is the most frequent pediatric glomerular disease, affecting from 1.15 to 16.9 per 100,000 children per year globally. It is characterized by massive proteinuria, hypoalbuminemia, and/or concomitant edema. Approximately 85-90% of patients attain complete remission of proteinuria within 4-6 weeks of treatment with glucocorticoids, and therefore, have steroid-sensitive nephrotic syndrome (SSNS). Among those patients who are steroid sensitive, 70-80% will have at least one relapse during follow-up, and up to 50% of these patients will experience frequent relapses or become dependent on glucocorticoids to maintain remission. The dose and duration of steroid treatment to prolong time between relapses remains a subject of much debate, and patients continue to experience a high prevalence of steroid-related morbidity. Various steroid-sparing immunosuppressive drugs have been used in clinical practice; however, there is marked practice variation in the selection of these drugs and timing of their introduction during the course of the disease. Therefore, international evidence-based clinical practice recommendations (CPRs) are needed to guide clinical practice and reduce practice variation. The International Pediatric Nephrology Association (IPNA) convened a team of experts including pediatric nephrologists, an adult nephrologist, and a patient representative to develop comprehensive CPRs on the diagnosis and management of SSNS in children. After performing a systematic literature review on 12 clinically relevant PICO (Patient or Population covered, Intervention, Comparator, Outcome) questions, recommendations were formulated and formally graded at several virtual consensus meetings. New definitions for treatment outcomes to help guide change of therapy and recommendations for important research questions are given.

MO1041: C.E.R.A. (Continuous Erythropoietin Receptor Activator—Methoxy Polyethylene Glycol Epoetin Beta) In Paediatric Dialysis Patients with Anaemia of Chronic Kidney Disease: Real-World Evidence from the IPDN and IPHN Registries

BACKGROUND AND AIMS

Continuous erythropoietin receptor activator—methoxy polyethylene glycol epoetin beta (C.E.R.A.) is a long-acting erythropoiesis-stimulating agent (ESA) approved for the treatment of anaemia associated with chronic kidney disease (CKD) in adults. In June 2018, the Food and Drug Administration approved the use of C.E.R.A. administered intravenously in patients on haemodialysis aged 5–<18 years switching from another ESA. This observational real-world study (MH40258) assessed the safety, dosing and haemoglobin (Hb) levels associated with C.E.R.A. in paediatric patients with CKD on dialysis.

METHOD

This was a non-interventional real-world study of patients from the International Paediatric Peritoneal Dialysis Network (IPPN) and the International Paediatric Hemodialysis Network (IPHN) registries. Demographics, clinical characteristics, dialysis information, treatment, laboratory parameters, number and causes of hospitalization events and deaths were reported in patients treated with C.E.R.A. from both registries (IPPN: 2007–2021; IPHN: 2013–2021).

RESULTS

Overall, 229 patients had at least one observation while being treated with C.E.R.A. and were analysed in this study; 177 on peritoneal dialysis (PD) (median age 10.6 years, interquartile range [IQR] 4.2–14.6) and 52 on haemodialysis (HD) (median age 14.1 years, IQR 10.4-16.2). The median observation time under C.E.R.A. exposure was 6 months (IQR 0–12.5) for PD patients and 12 months (0–18) for HD patients. 121 PD patients (68%) and 36 HD patients (69%) had ≥ 1 hospitalization, of whom 102/121 (84%) and 32/36 (89%), respectively, had non-elective hospitalizations. Median hospitalization surveillance time/patient was 13.5 months in the PD and 18.3 months in the HD cohorts. The most frequent causes for non-elective hospitalization were infections, reported as a cause in 56/177 (32%) patients in the PD cohort and 14/52 (27%) in the HD cohort and technique complications, in 41/177 (23%) patients in the PD cohort and 20/52 (38%) in the HD cohort. There were seven deaths (PD: 5 patients; HD: 2 patients), corresponding to an overall mortality rate of 19.8 cases per 1000 observation years. Causes of death were infections (n = 2), intracranial bleeding (n = 2), congestive heart failure (n = 2) and one case of sudden death at home. Hb levels remained stable over time with 47% of PD patients and 48% of HD patients having a Hb value within the range of 10–12 g/dL at their last observation. Mean [standard deviation (SD)] Hb levels at last observation were 10.9 (1.7) g/dL in the PD and 10.4 (1.7) g/dL in the HD cohort. The median monthly dose of C.E.R.A. at first visit was 100 (IQR 50–120) µg in the PD and 107 (80–129) µg in the HD cohort, while at last visit it was 100 (50–150) µg (PD) and 80 (54–129) µg (HD). While absolute C.E.R.A. dose increased with age, weight-related doses decreased substantially with age in both cohorts: in groups aged < 2, 2–<5, 5–<12 and 12–<18 years, respectively, the median monthly dose was 7.9, 5.4, 3.2 and 2.6 µg/kg at first observation and 5.1, 5.2, 3.0 and 3.0 µg/kg at last observation in the PD cohort. The age-related dosing differences were smaller when doses were normalized to body surface area (BSA) rather than body weight, with median doses at last visit of 114, 121, 87 and 98 µg/m2/month, respectively in the PD cohort. In the HD cohort, a similar pattern wasobserved regarding weight and BSA-based dosing, but overall C.E.R.A.dosing was generally lower over the course of the study in HD compared with PD patients. The median monthly C.E.R.A. dose at last observation was 3.5 (IQR 2.3– 5.1) µg/kg, or 95 (62–145) µg/m2 in the PD cohort and 2.1 (1.2–3.4) µg/kg, or 63 (40–98) µg/m2 in the HD cohort (Table).

CONCLUSION

Real-world data from the IPPN and IPHN registries indicated that C.E.R.A. treatment is associated with efficient maintenance of Hb levels in paediatric patients with CKD on dialysis. C.E.R.A. appeared to have a favourable safety profile; analysis of hospitalization rate and causes as well as patient mortality did not reveal any safety signals.

Long-term outcome of early steroid withdrawal in pediatric renal transplantation

BACKGROUND

Steroid use in renal transplant is related to multiple adverse effects. Long-term effects of early withdrawal steroids in pediatric renal transplant were assessed.

METHODS

Renal transplant children with low immunological risk treated on basiliximab, tacrolimus, and mycophenolate with steroid withdrawal or steroid control were evaluated between 2003 and 2019. Clinical variables, treatment adherence, acute rejection, graft loss, and death were analyzed through hazard ratios, and Kaplan-Meier and multivariate analyses.

RESULTS

The study included 152 patients, 71.1% steroid withdrawal, mean follow-up 8.5 years, 64.5% structural abnormalities, and 81.6% deceased donor. At 12 years of transplant, event-free survival analysis for graft loss or death showed no significant difference between steroid withdrawal and control steroid treatment (85.9% vs. 80.4%, p = .36) nor in acute rejection at 10 years (18.5% vs. 20.5%, p = .78) or in donor-specific antibody appearance (19.6% vs. 21.4%, p = .98). Delta height Z-score was increased in the steroid withdrawal group (p < .01). The main predictor of graft loss or death was non-adherence to treatment (p = .001; OR: 17.5 [3.3-90.9]).

CONCLUSIONS

Steroid withdrawal therapy was effective and safe for low-risk pediatric renal transplant in long-term evaluation. Non-adherence was the main predictor of graft loss or death.

Fecal Calprotectin and Eosinophil-Derived Neurotoxin in Children with Non-IgE-Mediated Cow's Milk Protein Allergy

Our aim is to assess the efficacy of fecal calprotectin (fCP) and fecal eosinophil-derived neurotoxin (fEDN) as diagnostic markers of cow's milk protein allergy (CMPA) and for monitoring the infants' response to a non-IgE mediated cow's milk protein (CMP)-free diet. We prospectively recruited infants aged 0 to 9 months. Stool samples were taken from 30 infants with CMPA, 19 with mild functional gastrointestinal disorders, 28 healthy infants, and 28 children who presented mild infections. Despite the fact that levels of fCP and fEDN in CMPA infants were higher than in healthy infants at month 0, differences for both parameters did not reach statistical significance (p-value 0.119 and 0.506). After 1 month of an elimination diet, no statistically significant differences in fCP with basal levels were found (p-values 0.184) in the CMPA group. We found a high variability in the fCP and fEDN levels of young infants, and discrepancies in individual behavior of these markers after a CMP-free diet was started. It seems that neither fCP nor fEDN levels are helpful to discriminate between healthy infants and those with signs or symptoms related to non-IgE-mediated CMPA. Additionally, it is debatable if on an individual basis, fCP or fEDN levels could be used for clinical follow-up and dietary compliance monitoring. However, prospective studies with larger populations are needed to draw robust conclusions.

Urinary Extracellular Vesicles as a Source of NGAL for Diabetic Kidney Disease Evaluation in Children and Adolescents With Type 1 Diabetes Mellitus

BACKGROUND

Tubular damage has a role in Diabetic Kidney Disease (DKD). We evaluated the early tubulointerstitial damage biomarkers in type-1 Diabetes Mellitus (T1DM) pediatric participants and studied the correlation with classical DKD parameters.

METHODS

Thirty-four T1DM and fifteen healthy participants were enrolled. Clinical and biochemical parameters [Glomerular filtration Rate (GFR), microalbuminuria (MAU), albumin/creatinine ratio (ACR), and glycated hemoglobin A1c (HbA1c)] were evaluated. Neutrophil gelatinase-associated lipocalin (NGAL), Hypoxia-inducible Factor-1α (HIF-1α), and Nuclear Factor of Activated T-cells-5 (NFAT5) levels were studied in the supernatant (S) and the exosome-like extracellular vesicles (E) fraction from urine samples.

RESULTS

In the T1DM, 12% had MAU >20 mg/L, 6% ACR >30 mg/g, and 88% had eGFR >140 ml/min/1.72 m². NGAL in the S (NGAL-S) or E (NGAL-E) fraction was not detectable in the control. The NGAL-E was more frequent (p = 0.040) and higher (p = 0.002) than NGAL-S in T1DM. The T1DM participants with positive NGAL had higher age (p = 0.03), T1DM evolution (p = 0.03), and serum creatinine (p = 0.003) than negative NGAL. The NGAL-E correlated positively with tanner stage (p = 0.0036), the median levels of HbA1c before enrollment (p = 0.045) and was independent of ACR, MAU, and HbA1c at the enrollment. NFAT5 and HIF-1α levels were not detectable in T1DM or control.

CONCLUSION

Urinary exosome-like extracellular vesicles could be a new source of early detection of tubular injury biomarkers of DKD in T1DM patients.

Fecal calprotectin in healthy children aged 4-16 years

Reference values of fecal calprotectin (fCP) have not been convincingly established in children. We aimed to investigate fCP concentrations in a larger population of healthy children aged 4–16 years to analyze more in depth the behavior of fCP in this age range and to determine if cut-off levels could be conclusively recommended. A prospective study was conducted to investigate fCP concentrations of healthy children aged 4–16 years. In 212 healthy children, the median and 95th percentile for fCP were 18.8 mg/kg and 104.5 mg/kg, respectively. We found a statistically significant association between the 95th percentile of fCP concentrations and age (p < 0.001). We propose a nomogram to facilitate the interpretation of fCP results in children aged 4–16 years. Further studies are required to validate the proposed values in clinical practice.

[Renin Angiotensin Axis, Angiotensin Converting Enzyme 2 and Coronavirus]

The renin-angiotensin-aldosterone system (RAAS) is the main plasma volume regulator, which maintains cardiovascular and hydrosaline homeostasis. In the classical pathway, the angiotensin converting enzyme (ACE) generates Angiotensin II (AngII), which is powerfully inflammatory and vasoconstrictive. This classical pathway is also regulated by ACE2, which converts AngI to Ang 1-9, and degrades AngII to Ang 1-7, whose vasodilatory and anti-inflammatory functions balance out the effects of AngII. ACE2 has been associated with the pathogenesis of respiratory infections such as RSV and severe acute respiratory syndrome coronavirus (SARS-CoV and SARS-CoV-2). Recent studies have shown that ACE2 corresponds to the main SARS-CoV-2 receptor, which together with other receptors such as the TMPRSS2, allows the virus to attach, fuse, and enter the host cell. These studies have shown that in animals infected with coronavirus there is a drop in tissue concentration of ACE2 and Ang 1-7, leading to overexpression of AngII and its vasoconstrictive and inflammatory effects. Experiments with recombinant ACE2 have shown a protective effect against overexpression of RAAS in coronavirus-infected animals, which is similar to that demonstrated with the use of AngII receptor blockers (AT1). Evidence on the protective role of ACE2 seems to support the recommendations re garding not discontinuing these drugs in COVID-19 infection. In this article, we present the current knowledge about the role of RAAS in coronavirus infection, based on physiopathological concepts, molecular bases, and experimental and clinical evidence.

IPNA clinical practice recommendations for the diagnosis and management of children with steroid-resistant nephrotic syndrome

Idiopathic nephrotic syndrome newly affects 1-3 per 100,000 children per year. Approximately 85% of cases show complete remission of proteinuria following glucocorticoid treatment. Patients who do not achieve complete remission within 4-6 weeks of glucocorticoid treatment have steroid-resistant nephrotic syndrome (SRNS). In 10-30% of steroid-resistant patients, mutations in podocyte-associated genes can be detected, whereas an undefined circulating factor of immune origin is assumed in the remaining ones. Diagnosis and management of SRNS is a great challenge due to its heterogeneous etiology, frequent lack of remission by further immunosuppressive treatment, and severe complications including the development of end-stage kidney disease and recurrence after renal transplantation. A team of experts including pediatric nephrologists and renal geneticists from the International Pediatric Nephrology Association (IPNA), a renal pathologist, and an adult nephrologist have now developed comprehensive clinical practice recommendations on the diagnosis and management of SRNS in children. The team performed a systematic literature review on 9 clinically relevant PICO (Patient or Population covered, Intervention, Comparator, Outcome) questions, formulated recommendations and formally graded them at a consensus meeting, with input from patient representatives and a dietician acting as external advisors and a voting panel of pediatric nephrologists. Research recommendations are also given.

[ABC of the peritoneal dialysis in pediatrics]

End-stage renal disease (ESRD) has an incidence of 5.5 to 9 pmp, and a prevalence of 23 to 65 pmp in children under 15 years of age. Chronic peritoneal dialysis (PD) represents the most widely used renal replacement therapy in children before kidney transplantation. There are two PD modalities, the manual one (CAPD) and the automated one (APD). The choice is based on the peritoneum characteristics, evaluated through the peritoneal equilibrium test (PET), which divides patients into high transporters (rapid exchange membrane), high average, low average, and low transporters (slow exchange membrane). This test basically evaluates the solutes transport rate, and the MiniPET has been added which evaluates peritoneal free water transport. The amount of dialysis (Kt/V), which represents the dose of dialysis administered also must be evaluated to assure a minimal value of 1.7 related to morbidity and mortality. These parameters should be evaluated periodically to ad just the PD and whenever suspected an inadequate clearance or ultrafiltration. The objective of this review is to provide basic concepts on peritoneal transport physiology, PD modalities, free water transport and peritoneal solute transport evaluation, and the dialysis dose to be applied according to the patient's needs, as well as reviewing the correction mechanisms and procedure adjustment whenever required.

Eje Renina Angiotensina, Enzima Convertidora de Angiotensina 2 y Coronavirus

El sistema renina angiotensina aldosterona (SRAA) es el principal regulador del volumen plasmático, manteniendo la homeostasis cardiovascular e hidrosalina. En la vía clásica, la enzima convertidora de angiotensina (ECA) genera Angiotensina II (AngII), de potente efecto inflamatorio y vasoconstrictor. Esta vía clásica es a su vez regulada por la ECA2, que convierte AngII a Ang 1-7, cuyas acciones vasodilatadoras y antiinflamatorias dan balance a los efectos de AngII. La ECA2 se ha relacionado con la patogenia de infecciones respiratorias como el virus respiratorio sincicial y el síndrome respiratorio agudo grave por coronavirus (SARS-CoV y SARS-CoV-2). Estudios recientes han demostrado que la ECA2 corresponde al principal receptor del SARS-CoV-2, que en conjunto con otros receptores como la serin proteasa TMPRSS2, permiten la fijación, fusión y entrada del virus a la célula huésped. En animales infectados por SARS-CoV se produce una caída de la concentración tisular de ECA2 y Ang 1-7, con la consiguiente sobreexpresión de AngII, y sus efectos vasoconstrictores e inflamatorios. Experimentos con ECA2 recombinante han mostrado un efecto protector frente a la sobreexpresión del SRAA en animales infectados por SARS-CoV, efecto similar al demostrado con el uso de bloqueadores del receptor de AngII, AT1. La evidencia sobre el rol protector de ECA2 parece respaldar las recomendaciones respecto a no suspender estos medicamentos en la infección SARS-CoV-2. En este artículo presentamos el conocimiento actual sobre el rol del SRAA en la infección por SARS-CoV, a partir de conceptos fisiopatológicos, bases moleculares, y evidencia experimental y clínica.

P1552CAN WE GET ADEQUATE DIALYSIS WITH LIQUID AT 300 ML/MIN ?

Background and Aims

The portable HD monitors achieve a good adaptation with HD dialysate at 200ml / min using the concept of saturation of the HD dialysate. We decrease from 800ml / min to 500ml / min with good adaptation some years ago.

To assess the effectiveness of HD in both HD-standard and HDF-online with dialysate flow at 300ml / min by establishing approximate mathematical model of clearance.

Methods

We conducted an HD session with dialysate flow at a speed of 300ml / min, half week session to 52 patients in our unit. We value vascular access, session time, liters of blood-purified and total infusion in HDF online. We review HD monitor and dialyzer.

We perform pre and postHD blood determinations: Urea, B2microglobulin, P and uric acid, assessing urea reduction rate (PRU), b2microglobulin reduction rate (PR2microg) with both dialysate flows at 300ml / min and 500ml / min. We also have evaluated the differences between the two methods.

In the HD dialysate flow we determine at 300ml / min at 5, 10, 30, 45 and 60min (total dialysate collection in the first hour with sample of the mixture) urea, B2microg, Uric acid and P and at 2, 3 and 4 hours establishing a mathematical model with an approximation curve in both HD and online HDF.

Results

Five patients in standard HD (4h), 35 HDF online (4h) (x Liters infused 24.87 ± 2.79 l) and 12 short-daily HD (2h30min). 18 catheter and 34 FAV. Xliters purified blood = HD daily 54.41 ± 5.63l, HD standard 87.38 ± 6.01 and HDFonline 82.02 ± 16.13l.

The xPRU = 76.17 ± 10.49%, PRB2microg = 73.82 ± 13.49, Kt / V = 1.52 ± 0.28. By scheme at 300ml / min of HD fluid flow: HDFonline xPRU = 81.54 ± 5.25, Standard HD = 78.01 ± 3.03, Daily HD = 60.19 ± 6.71; xPRb2microg HDFonline = 76.70 ± 14.76%, Standard HD 65.44 ± 11.81, Daily HD = 69.16 ± 6.49.

Comparing the xPRU at 300ml / min of liquid vs 500ml / min we didn´t found significant differences, nor in the x preHD of urea and B2microglobulin.

With the dialysate samples we obtain a polynomial model of order 7 allowing cuantitative adjustment of the curve.R2 0.9, observing in the first 2 hours the greater removing.

Conclusions

1. The results are sufficient to consider the result of the removing in each scheme adequate. 2. The decrease in costs would be important (40% of water + energy saving and longer duration elements water treatment. 3. Further study are necessary.

Prescribing peritoneal dialysis for high-quality care in children

Background:

Peritoneal dialysis (PD) remains the most widely used modality for chronic dialysis in children, particularly in younger children and in lower and middle income countries (LMICs). We present guidelines for dialysis initiation, modality selection, small solute clearance, and fluid removal in children on PD. A review of the literature and key studies that support these statements are presented.

Methods:

An extensive Medline search for all publications on PD in children was performed using predefined search criteria.

Results:

High-quality randomized trials in children are scarce and current clinical practice largely relies on data extrapolated from adult studies or drawn from observational cohort studies in children. The evidence and strength of the recommendation is GRADE-ed, but in the absence of high-quality evidence, the opinion of the authors is provided and must be carefully considered by the treating physician, and adapted to local expertise and individual patient needs as appropriate. We discuss the timing of dialysis initiation, factors to be considered when selecting a dialysis modality, the assessment and management of volume status on PD, achieving optimal small solute clearance, and the importance of preserving residual kidney function. While optimal dialysis must remain the goal for every patient, a careful discussion with fully informed patients and caregivers is important to understand the patient and family’s expectations of dialysis and reasonable adjustments to the dialysis program may be considered in accordance with a philosophy of shared decision-making.

Conclusions:

There continues to be very poor evidence in the field of chronic PD in children and these recommendations can at best serve to guide clinical decision-making. In LMICs, every effort should be made to conform to the framework of these statements, taking into account resource limitations.

Free Water Transport and Its Association with Cardiovascular Status in Children on Peritoneal Dialysis

Background:Volume overload is one of the most important factors associated with left ventricular hypertrophy (LVH) and cardiovascular disease in chronic peritoneal dialysis (PD) patients. MiniPET is a reliable tool to evaluate free water transport (FWT). In a clinical setting, the significance of FWT has not been evaluated in terms of outcome in children on PD. The objective was to define a FWT value of clinical significance in children on PD, fixing its relationship to left ventricular mass index (LVMI) as a well-known outcome parameter.Methods:MiniPET was performed with 3.86% glucose, 1-h long, to measure FWT in PD patients > 6 years old. An echocardiogram (ECG) was performed within 2 months of the MiniPET. Left ventricular hypertrophy was defined as LVMI ≥ 38.6 g/height^2.7 (95th percentile). Receiver operating characteristic curve (ROC) analysis was used to determine the cut-off value of FWT searching the highest sensitivity and specificity to differentiate patients with normal/abnormal LVMI. A p < 0.05 was considered significant.Results:Forty-six studies were performed on 32 patients, 16 males; mean age 11.59 ± 3.07 years. Mean normalized FWT (nFWT) was 144.4 ± 84.8 mL/m², corresponding to 46.7% of total ultrafiltration. Mean LVMI was 42 ± 11.3 g/m^2.7 with a negative correlation to nFWT (p < 0.01). Eighteen out of 32 patients had LVH. The ROC analysis (nFWT vs LVMI) showed an area under the curve of 0.71 (95% confidence interval [CI], 0.53 - 0.89; p = 0.04), allowing a cut-off nFWT value of 110 mL/m² to be defined, dividing the population into 2 groups of patients according to the LVMI cut-off value of 38,6 g/m^2.7.Conclusions:The nFWT showed an inverse correlation to LVMI. A nFWT value < 110 mL/m² was significantly associated with LVH. The negative relationship observed between nFWT and LVMI, and the cut-off level for nFWT according to the 95th percentile of LVMI, suggest that the regular evaluation of nFWT could become a useful tool in assessing the capacity of PD treatment to keep patients' volume status under control, avoiding cardiovascular impairment.

Self-Regulation Questionnaire (SRQ) in Spanish Adolescents: Factor Structure and Rasch Analysis

Background: The Self-Regulation Questionnaire (SRQ) is an instrument employed to measure the generalized ability to regulate behavior. Self-regulation is related to the management of risk behaviors, such as drug abuse or anti-social behaviors. The SRQ has been used in young adult samples. However, some risk behaviors are increasing among adolescents. The aim of this study is to examine the psychometric properties of the SRQ among Spanish adolescents.

Methods: 845 high-school Spanish students (N = 443; 52.43% women), from 12 to 17 years old and ranging from the first to the fourth year of studies, completed the SRQ. A confirmatory factor analysis (CFA) was carried out in order to establish structural adequacy. Then, a study of each subscale was conducted using the Rasch model for dimensionality, adjustment of the sample questions, functionality of the response categories, and reliability.

Results: While controlling for method effects, the data showed goodness of fit with the four-factor solution and 17 items (Goal setting, Decision making, Learning from mistakes, and Perseverance), and the four sub-scales were unidimensional according to the Rasch analysis. The Rasch model itself was shown to be reliable, but not at the level of persons. This means that the instrument was not sensitive enough to discriminate people with different self-regulation levels.

Discussion: These results support the use of the Spanish Short SRQ in adolescent samples. Some suggestions are made to improve the instrument, particularly in its application as a diagnostic tool.

Renal replacement therapy for children throughout the world: the need for a global registry

BACKGROUND

To describe the factors affecting the incidence of renal replacement therapy (RRT) among children, information from RRT registries is required. We aimed to give an overview of existing pediatric RRT registries worldwide, identify regions with a need to commence or increase data collection on pediatric RRT, and provide a rationale for developing a global RRT registry.

METHODS

A survey assessing pediatric RRT registry status was sent to International Pediatric Nephrology Associateion (IPNA) members in 127 countries in January 2016. The survey was complemented by a systematic literature search for active pediatric RRT registries.

RESULTS

Complete survey responses were retrieved from 94 countries (representing 86.2% of the world childhood population), with 84 (81.2%) having the means to provide RRT to children, given that there are no other limitations such as financial, social, or religious restraints. Fifty-one (35.3%) countries had national registries for both dialysis and transplantation, nine (30.0%) either had a dialysis or a transplant registry, six participated in international registries only (2.7%), and in 18 (13.2%), children on RRT were not followed in any registry. The search identified 92 pediatric RRT registries, primarily national registries located in Europe, North America, and Asia.

CONCLUSIONS

Although pediatric RRT can be provided in 84 countries representing 81.2% of the world's childhood population, national pediatric RRT registries are unavailable in many countries. To improve knowledge about the incidence and outcomes of pediatric RRT around the globe, an international population-based pediatric RRT registry has recently been initiated.

Catalan contribution in the European project MEntally Disturbed Inmates Care and Support (MEDICS)

OBJECTIVE

To know the criteria of penitentiary professionals about the causes, management methods and improvement proposal, in the attention and care of inmates suffering non-serious mental disorders.

MATERIAL AND METHODS

Activity developed from March to May 2015. In Catalonia, three prisons participated. Seven different models of anonymous and written questionnaires were distributed, designed by Italy, and aimed at directors, treatment teams, correctional officers, teachers, doctors, nursing staff and volunteers. They presented the degree of participation, descriptive characteristics of groups and main answers given. To study the association between qualitative variables, the Chi squared and the exact Fisher test was used.

RESULTS

Questionnaires distributed among the 744 employees and there were obtained 174 filled (23.4%). There was more participation among health staff and treatment teams (88% and 36%). About the age of participants, doctors were the most senior group with meaningful differences (p <0.001). 40.7% were men and 57.7% women. Among the non-health staff 70% of correctional officers held a degree. Most of the total (62.4%) had their work as their main sources of knowledge about mental health. The main answers given are presented.

DISCUSSION

Almost 25% of penitentiary professionals participated in the MEDICS project. Most of them (67%) held a degree. There is a professional concern about mental disorders but not discrimination. Some groups (doctors and, specially, non-health professionals) believe as basic a continuing training and working in multidisciplinary teams.

[Peritoneal dialysis adequacy in pediatrics. From the peritoneal equilibration test to the aquaporins]

An evaluation of the characteristics of peritoneal solute and water transport is essential to assess the suitability of prescribing dialysis in patients suffering from chronic renal disease. There are currently a series of models to perform this evaluation. The peritoneal equilibration test (PET) evaluates the peritoneal transport capacity, classifying the patients into four transport categories: high, high-average, low-average, and low. The short PET enables the same evaluation to be made in only 2hours, and has been validated in paediatric patients. On the other hand, the MiniPET provides additional information by evaluating the free water transport capacity by the ultra-small pores, and the Accelerated Peritoneal Examination Time (APEX) evaluates the time when the glucose and urea equilibration curves cross, and has been proposed as the optimum dwell time to achieve adequate ultrafiltration. An analysis is presented on the current information on these diagnostic methods as regards free water transport via aquaporins, which could be an important tool in optimising solute and water transport in patients on chronic peritoneal dialysis, particularly as regards the cardiovascular prognosis.

Resolving the electrospinnability zones and diameter prediction for the electrospinning of the gelatin/water/acetic acid system

The development of suitable biomimetic scaffolds is a fundamental requirement of tissue engineering. Although electrospinning has emerged as an effective method for producing such scaffolds of nanometer-sized fibers, the influence of solution characteristics on the morphology of the resulting nanofibers depends on each polymer solution system. In this study, gelatin nanofibers and microfibers were prepared via electrospinning using mixtures of water and acetic acid at different ratios as solvents. The viscosities of gelatin solutions before electrospinning were analyzed and two different behaviors were found as a function of the solvent composition, taking into account classic models of polymer science. A power law relationship between viscosity and gelatin concentration was found for each solvent system, and an empirical model including the influence of acetic acid was obtained for aqueous systems. Moreover, a ternary diagram considering gelatin, water, and acetic acid mass fractions was constructed as a tool to establish the electrospinnability domains in terms of fiber occurrence and morphology. Also, the isodiametric curves were defined in the fibers region. Finally, in order to correlate the diameter of electrospun nanofibers and the electrospinnability zones, the Berry number was used. However, as its only allows the range of electrospinnability to be established for a fixed solvent composition, a new dimensionless parameter (Bemod) was suggested to take into account all the acetic acid aqueous solutions as a single solvent.

Steroid withdrawal in pediatric kidney transplant allows better growth, lipids and body composition: a randomized controlled trial

BACKGROUND

Glucocorticoid immunosuppressant therapy in pediatric kidney transplant (Tx) recipients does not allow the improvement of growth after Tx.

OBJECTIVE

To determine the effect of early steroid withdrawal (SW) on longitudinal growth, insulin sensitivity (IS), and body composition (BC).

METHODS

This was a prospective, randomized, multicenter study in Tx. Insulin-like growth factor (IGF)-I, IGF-binding protein 3 (IGFBP3), IS, and BC (DEXA/pQCT) were determined at baseline and up to 12 months after Tx.

RESULTS

A total of 30 patients were examined; 14 patients were assigned to the SW group (7 male, 7 female; 12 in Tanner stage I) and 16 patients were assigned to the steroid control (SC) group (10 male, 6 female;12 in Tanner stage I). Their chronological age was 7.8 ± 4.3 years, height was -2.3 ± 0.99 SD scores (SDS), and body mass index -0.3 ± 1.2 SDS. After 1 year, the SW group showed an increase in height SDS (+1.2 ± 0.22 vs. +0.60 ± 0.13 SDS in the SC group, p < 0.02), lower IGFBP3 (p < 0.05), cholesterol (p < 0.05), and higher high-density lipoprotein cholesterol (p < 0.05). SW patients had lower trunk fat with no differences in IS. Only in prepubertal patients, the SW group had lower glycemia (p < 0.05), very low-density lipoprotein cholesterol (p < 0.01), triglycerides (p < 0.05), triglycerides/glycemia index (TyG; p < 0.02), and better lean mass. Both groups showed an improvement in lean mass after kidney Tx.

CONCLUSIONS

SW improved longitudinal growth, lipid profile, and trunk and lean fat in Tx patients. In prepubertal recipients, the decrease in TyG suggests better IS.

The mini-PET in pediatric peritoneal dialysis: a useful tool to predict volume overload?

BACKGROUND

Cardiovascular disease (CVD) in patients on chronic peritoneal dialysis (PD) is a major cause of death and is closely linked to hypertension and volume overload. The mini-Pet has been proposed as a useful tool to evaluate free-water transport (FWT) and characterize ultrafiltration across the peritoneum. Knowledge regarding FWT could be of great value to predict volume overload in PD patients. Our objective in this study was to characterize FWT through the peritoneum in children on PD.

METHODS

We studied clinically stable patients with >2 months on PD. Exclusion criteria were a peritonitis episode up to 2 months prior to entrance into the study and active nephrotic syndrome. A 1-h mini-peritoneal equilibration test (mini-PET) was performed with 3.86 % glucose. Calculations (see text for full definitions) were: Dip Na (Na dial min60 - Na dial min1), Dip D/PNa (D/PNa60 - D/PNa1), total Na removal (NaR = total Na dial60 - Na dial1), ultrafiltration small pores [(UFSP = NaR × 1,000)/Nap], and FWT (UF-UFSP). Peritoneal equilibration test (PET), left ventricular mass index (LVMI, g/m(2)), daily UF, and residual renal function were evaluated. Pearson's correlation coefficient was used to establish correlation between variables.

RESULTS

Sixteen patients were included, with a mean age of 11.8 ± 3.8 years. Free water transport normalized to body surface area (BSA) (FWTn) was 133.9 ± 85.7 ml/m(2); creatinine dialysate-to-plasma (D/P) and glucose dialysate at X dwell time-to-0 dwell time (Dx/D0) ratios were 0.38 ± 0.1 and 0.65 ± 0.09, respectively. LVMI was 46.6 ± 14.8 g/m(2); 2-h creatinine D/P and glucose Dx/D0 showed no correlation with FWTn, UF, and LVMI. FWTn showed a significant inverse correlation with LVMI (r 0.58, p 0.02).

CONCLUSIONS

This study characterized FWT in PD children through the mini-PET. Left ventricular hypertrophy showed a high prevalence in this group, and a significant correlation between LVMI and FWT was found. FWT could be a useful tool to evaluate UF in PD children.

Management of anemia in children receiving chronic peritoneal dialysis

Little information exists regarding the efficacy, modifiers, and outcomes of anemia management in children with CKD or ESRD. We assessed practices, effectors, and outcomes of anemia management in 1394 pediatric patients undergoing peritoneal dialysis (PD) who were prospectively followed in 30 countries. We noted that 25% of patients had hemoglobin levels below target (<10 g/dl or <9.5 g/dl in children older or younger than 2 years, respectively), with significant regional variation; levels were highest in North America and Europe and lowest in Asia and Turkey. Low hemoglobin levels were associated with low urine output, low serum albumin, high parathyroid hormone, high ferritin, and the use of bioincompatible PD fluid. Erythropoiesis-stimulating agents (ESAs) were prescribed to 92% of patients, and neither the type of ESA nor the dosing interval appeared to affect efficacy. The weekly ESA dose inversely correlated with age when scaled to weight but did not correlate with age when normalized to body surface area. ESA sensitivity was positively associated with residual diuresis and serum albumin and inversely associated with serum parathyroid hormone and ferritin. The prevalence of hypertension and left ventricular hypertrophy increased with the degree of anemia. Patient survival was positively associated with achieved hemoglobin and serum albumin and was inversely associated with ESA dose. In conclusion, control of anemia in children receiving long-term PD varies by region. ESA requirements are independent of age when dose is scaled to body surface area, and ESA resistance is associated with inflammation, fluid retention, and hyperparathyroidism. Anemia and high ESA dose requirements independently predict mortality.

The plasma permeability factor in nephrotic syndrome: indirect evidence in pediatric peritoneal dialysis

BACKGROUND

Nephrotic syndrome (NS) in children has been associated with a systemic circulating permeability factor. Therefore, once peritoneal dialysis (PD) has been started, peritoneal protein losses should be higher in the nephrotic than in the non-nephrotic population.

OBJECTIVE

We compared peritoneal protein losses in children with and without NS on PD.

METHODS

Our retrospective 4-year study analyzed Hispanic patients with NS under PD. Data at dialysis entry and 6 months later were compared. Nutritional support was given according to recommended dietary allowances and recommendations from the Kidney Disease Outcomes Quality Initiative. Clinical and biochemical data were obtained, and 24-hour dialysate and urine samples were collected to measure protein losses. Dialysis dose (Kt/V), daily protein intake (DPI), normalized protein equivalent of nitrogen appearance (nPNA), peritoneal equilibration test (PET), and peritonitis rate were determined. All measurements took place at least 4 weeks after resolution of a peritonitis episode. All patients received automated PD using a HomeChoice PD System cycler (Baxter Healthcare Corporation, Deerfield, IL, USA), with an exchange volume of 1100 mL/m(2) and a dextrose concentration of 1.5% - 2.5%. A control group of non-NS children on PD matched by age and sex were also studied. Data are reported as mean ± standard deviation. Differences between groups were calculated using the Mann-Whitney U-test, and p < 0.05 was considered significant.

RESULTS

Each study group consisted of 10 patients [NS patients: 4 boys, mean age of 7.3 ± 4.1 years; control patients: 6 boys, mean age of 7.2 ± 4.7 years (p = nonsignificant)]. In the group with NS, 8 patients were diagnosed by biopsy as having focal segmental glomerulosclerosis, and 2 as having minimal-change disease. At study entry, patients with NS had hourly urinary protein losses of 398 ± 313 mg/m(2) and daily peritoneal protein losses of 3.4 ± 1.9 g/m(2), compared with 29.9 ± 31 mg/m(2) and 1.5 ± 1.1 g/m(2) respectively in the control group (p < 0.05). The same statistical difference was found 6 months later. We observed no statistical differences in PET results, daily exchange volume, and mean dextrose concentration of dialysate. Similarly, no significant between-group differences were observed for Kt/V, DPI, nPNA, and biochemical parameters.

CONCLUSIONS

Hispanic children with NS on PD show higher peritoneal protein losses than do their control counterparts. Such differences could be secondary to increased peritoneal permeability caused by a systemic permeability factor.

Trends in chronic complications of type 2 diabetic patients from Spanish primary health care centres (GEDAPS study): ten year-implementation of St. Vincent recommendations

AIMS

To assess the implementation of St. Vincent recommendations in Catalonia (Spain) between 1993 and 2003 following a program of Continuous Quality Improvement.

METHODS

65 health centres (433 health professionals) took part in the study. From 1993 to 2003, 34 workshops on consensus guidelines and feedback referring to the variables that needed to be improved were carried out. Data collection was obtained concerning, socio-demographic information, and disease characteristics and complications from patients with type 2 diabetes mellitus (DM).

RESULTS

Most cardiovascular risk factors improved: glycosilated haemoglobin (HbA1c) was reduced by 0.7% (95% CI: -0.49:-0.90); total cholesterol by 0.54mmol/L (95% CI: -0.53:-0.55); non-high density lipoprotein cholesterol by 0.81mmol/L (95% CI: -0.80:-0.82); systolic blood pressure (SBP) by 6.02mmHg (95% CI: -5.79:-6.25), and diastolic blood pressure (DBP) by 2.65mmHg (95% CI: -2.4:-2.9), with the exception of smoking and obesity, which increased by 2.1% and 5.9%, respectively. Retinopathy and albuminuria decreased by 40.7% and 46% (p<0.001), respectively. The incidence of diabetic foot lesions and amputations decreased by 65.7% and 61.1% (p<0.001), respectively. The prevalence of macrovascular complications showed a slight reduction (p=0.037). Ischemic cardiomyopathy and cerebrovascular accidents decreased by 7.7% and 17.6%, respectively.

CONCLUSIONS

Our Continuous Quality Improvement program based on St. Vincent recommendations, had a positive impact on cardiovascular risk factors. We observed a reduction of chronic complications in type 2 DM patients.

Early steroid withdrawal in pediatric renal transplant: five years of follow-up

This prospective, comparative trial investigated the impact on mean change in height standard deviation score (SDS), acute rejection rate, and renal function of early steroid withdrawal in 96 recipients with 5 years of follow-up. Recipients under basiliximab induction and steroid withdrawal (SW: TAC/MMF; n = 55) were compared with a matched steroid control group (SC: TAC/MMF/STEROID, n = 41). SW received steroids until Day 6, SC decreased to 10 mg/m(2) within 2 months post-transplant. Five years after SW, the longitudinal growth (SDS) gain was 1.4 ± 0.4 vs. 1.1 ± 0.3 for SC group (p < 0.02). Height benefits in prepubertal and pubertal status in both groups were demonstrated in the delta growth trends (mixed model; p < 0.01). Biopsy-proven acute rejection in SW was 11% and 17.5%, SC (p: ns). Mean eGFR (ml/min/1.73 m(2)) at 5 years post-transplant was SW 80.6 ± 27.8 vs. 82.6 ± 25.1 for SC (p: ns). The death-censored graft survival rate at 1 and 5 years was 99 and 90% for SW; 98 and 96% for SC (p = ns). PTLD incidence in SW 3.3 vs. 2.5% in SC (p: ns). Five years post-transplant, early steroid withdrawal showed positive impacts on growth, stable renal function without increased acute rejection risk, and PTLD incidence.

Voiding dysfunction: another etiology of vulvovaginitis in young girls

OBJECTIVE

To determine the prevalence of voiding dysfunction (VD) in patients with persistent vulvovaginitis (PVV), and to evaluate the clinical response of PVV in the treatment of VD.

PATIENTS AND METHODS

Girls four years or older who consulted for PVV for at least one month and who did not respond to general measures. A physical examination was performed with visual inspection and colposcopy; vaginal samples for culture and vaginoscopy were carried out. On every patient urodynamic studies were performed. Girls who were diagnosed with VD were treated. A pediatric gynecologist did the follow-up; a successful response was considered when inflammatory symptoms and vaginal discharge ceased.

RESULTS

Twenty patients were included, mean age 8.6 years (range: 4.6-14 years); 75% prepubertal symptoms lasted for 1.8 years; 19 (95%) had urodynamia, 10 (52.6%) had an overactive bladder, 8 (42.1%) external bladder sphincter dyssynergia, 1 (5.2%) hypotonic bladder, and 13 (65%) showed improvement.

CONCLUSION

VD is an important cause when considering the etiology of PVV.

[Hypovitaminosis D in pediatric patients on renal replacement therapy]

BACKGROUND

Hypovitaminosis D has a high prevalence among patients with chronic kidney disease (CKD).

AIM

To determine the prevalence of 25 hydroxy vitamin D (25(OH) D) insufficiency and deficiency in pediatric patients on dialysis and kidney transplantation.

MATERIAL AND METHODS

Serum calcium and phosphorus, parathormone (PTH), alkaline phosphatases and 25 (OH)D were measured in 13 children on hemodialysis (HD), 18 on peritoneal dialysis (PD) and 53 that received an allograft (Tx), aged 9.8 ± 4.6 years (51% females).

RESULTS

Fifty four percent of patients had height Z score less than -1.88. Patients on HD had the lowest values. The average time of replacement therapy was 2.9 ± 2.8 years. Mean 25(OH)D levels in all was 18.7 ± 10.7ng/ml (HD: 21 ± 16.8, PD: 18.9 ± 8.5, Tx: 18.1 ± 9.72 ng/ml). Eighty eight percent of patients had levels below 30 ng/ml. Mean of serum calcium was 9.5 ± 0.64 mg/dl, serum phosphorus 5.03 ± 1.02 mg/dl, calcium-phosphorus product 48 ± 11.8 mg/dl and alkaline phosphatases 300.5 ± 171.3 IU/L. Average PTH values in dialyzed and Tx patients were 724.6 ± 640.5 and 107.7 ± 56.2 pg/ml, respectively (p < 0.001). A positive correlation between 25 (OH) D and calcium levels among PD patients was observed (r = 0.490, p = 0.04).

CONCLUSIONS

Hypovitaminosis D is highly prevalent among children on renal substitution therapy, regardless of the type of therapy used and the stage of renal failure.

Short PET in pediatric peritoneal dialysis

Peritoneal equilibration test (PET) is a common technique used in children to evaluate peritoneal membrane transport capacity and adequate the dialysis regimen. Considering that this is a laborious test, a shortened version has been proposed. Our goal was to evaluate the concordance between the 2-h (short) and 4-h (classical) PET values to determine whether the short PET could be used in the clinical setting. Eighty-one PET corresponding to 81 peritoneal dialysis patients from two pediatric nephrology centers were retrospectively analyzed. Peritoneal transport capacity was evaluated using the dialysate to plasma ratio (D/P) of creatinine and the ratio of dialysate glucose to baseline dialysate glucose (D/D(0)) at 2 and 4 h. The mean [+/- standard deviation (SD)] creatinine D/P ratio at 2 and 4 h were 0.41 +/- 0.13 and 0.66 +/- 0.17, respectively, and the mean (+/- SD) D/D(0) glucose were 0.64 +/- 0.11 and 0.39 +/- 0.12 at the same times. Applying McNemar chi(2) test to evaluate the association between the categories obtained at 2 and 4 h, we found no relationship between the 2- and 4-h PET for both D/P and D/D(0) (p > 0.05). These results suggest that the use of this abbreviated test is probably not reliable for estimating the transport capacity of the peritoneal membrane in the pediatric population.

MLL gene fusions in human leukaemias: in vivo modelling to recapitulate these primary tumourigenic events

Recurrent reciprocal chromosomal translocations are frequently found in leukaemias and sarcomas as initiating events in these cancers. Mouse models of chromosomal translocations are not only important for the elucidation of the mechanism of these factors underlying the disease but are also important pre-clinical models for assessing new drug combinations, developing new rational therapeutic strategies based on new drugs and testing novel macromolecular drugs. We describe three technologies for creating chromosomal translocation mimics in mice, applied specifically to understand how the MLL-fusions contribute to leukaemia. An important finding of this work is that the lineage of the tumours can be controlled by the MLL-protein fusion. The translocation mimic methods can be applied to any human reciprocal chromosomal translocation.

Early steroid withdrawal in pediatric renal transplant on newer immunosuppressive drugs

Steroids have been a cornerstone in renal transplant immunosuppression. New immunosuppressive drugs have led to protocols using early steroid withdrawal or complete avoidance. A prospective protocol in 23 pediatric renal transplant (ages 2-14 yr) who received decreasing steroid doses stopping at day 7 post-Tx, FK, and MMF were compared with a CsA, AZT, historically matched steroid-based control group. Basiliximab was used in two doses. Anthropometric, biochemical variables, AR rates, and CMV infection were evaluated and compared using Student's t-test and regression analysis. A better growth pattern was seen in steroid withdrawal group. GFR rate and serum glucose were similar in both groups. Total serum cholesterol levels were significantly lower in steroid withdrawal group. The incidence of AR at 12 months was 4.3% in steroid withdrawal group vs. 8.6% in steroid-based group (p = ns). No difference in CMV infection was observed. Hemoglobin levels were low during the first months in both groups; reached normal values after six months. SBP became higher at 12 months in steroid-based group. Patient and graft survival was 98% in both groups at one-yr post-transplant. Early steroid withdrawal was efficacious, safe, and did not increase risk of rejection, preserving optimal growth, renal function, and reducing cardiovascular risk factors.

Leukaemia lineage specification caused by cell-specific Mll-Enl translocations

Chromosomal translocations involving the Mixed-Lineage Leukaemia (MLL) gene underlie many human leukaemias and MLL rearrangements are found in both acute myelogenous and acute lymphoblastic leukaemias. To assess the functionally relevant haematopoietic cell contexts for MLL fusions to be tumorigenic, we have generated different lines of mice in which de novo Mll-associated translocations occur. In these models, reciprocal chromosomal translocations occur by means of Cre-loxP-mediated recombination (translocator mice) in different cells of the haematopoietic system (namely haematopoietic stem cells, semi-committed progenitors or committed T or B cells). Translocations between Mll and Enl cause myeloid neoplasias, initiating in stem cells or progenitors while no tumours arose when the translocation was restricted to the B-cell compartment. Despite the absence of tumorigenesis, Mll-Enl translocations did occur and Mll-Enl fusion mRNA was expressed in B-cell-restricted translocators. A permissive cellular environment is therefore required for oncogenicity of Mll-associated translocations since the occurrence of Mll-Enl does not promote unrestricted proliferation in all haematopoietic cellular contexts, consistent with a specific instructive role of the MLL-fusion proteins in leukaemogenesis.

Mutations in the tight-junction gene claudin 19 (CLDN19) are associated with renal magnesium wasting, renal failure, and severe ocular involvement

Claudins are major components of tight junctions and contribute to the epithelial-barrier function by restricting free diffusion of solutes through the paracellular pathway. We have mapped a new locus for recessive renal magnesium loss on chromosome 1p34.2 and have identified mutations in CLDN19, a member of the claudin multigene family, in patients affected by hypomagnesemia, renal failure, and severe ocular abnormalities. CLDN19 encodes the tight-junction protein claudin-19, and we demonstrate high expression of CLDN19 in renal tubules and the retina. The identified mutations interfere severely with either cell-membrane trafficking or the assembly of the claudin-19 protein. The identification of CLDN19 mutations in patients with chronic renal failure and severe visual impairment supports the fundamental role of claudin-19 for normal renal tubular function and undisturbed organization and development of the retina.

Epistemological beliefs and approaches to learning: their change through secondary school and their influence on academic performance

BACKGROUND

In recent decades, two lines of research, phenomenographic and meta-cognitive, have examined students' approaches and epistemological beliefs about learning. To date there has been very little research describing the change in epistemological beliefs in European secondary students, or analysing interrelationships between epistemological beliefs and approaches in order to explain their influence on academic performance.

AIMS

The first aim of this investigation is to analyse the change in epistemological beliefs and learning approaches in secondary students as they progress through their studies. The second aim is to examine the effects of epistemological beliefs on learning approaches, and learning approaches on academic performance.

SAMPLE

About 1,600 Spanish students, boys and girls, from several secondary schools took part in the study. They were between 12 and 20 years old and their average age was 14.79 years.

METHODS

Measures of epistemological beliefs (EQ: Epistemological Questionnaire), learning approaches (LPQ: Learning Process Questionnaire), and academic performance were obtained. Confirmatory factor analysis was used to examine the dimensionality of the EQ and LPQ questionnaires. In order to achieve our two aims, different statistical techniques were used: MANOVA and ANOVA for our first aim, and structural equation modelling for our second aim.

RESULTS

Throughout secondary education epistemological beliefs undergo change, becoming more realistic and complex, and deep-approach scores decline significantly. It was shown that, as predicted, epistemological beliefs influenced academic achievement directly, and also indirectly via students' learning approaches.

CONCLUSIONS

Our findings point to two conclusions. First, epistemological beliefs and learning approaches change as pupils advance in their studies. Second, the relationship between epistemological beliefs and academic achievement is mediated by approaches to learning.

Pediatric renal transplantation: a single center experience over 14 years

Between 1989 and 2003, 100 transplants were performed in 96 patients at the pediatric nephrology unit of the Calvo Mackenna Children's Hospital. Mean age 10.9 +/- 3.9 yr (1-17.6), 30% from LD. Donors were younger than 5 yr in five patients and all recipients received an 'en bloc' graft. Original disease was hypo/dysplasia 27%, reflux nephropathy 22 and 17% chronic glomerulonephritis. The immunosuppressive protocol during the first period (n = 56, 1989-2000): Cyclosporine, steroids and azathioprine, and during the second period (n = 44, 2001-2003): FK, steroids, MMF and anti-CD25 antibody (mAbs). AR was reported in 22 patients, 11% in LD, 31% in DD (p < 0.01). The AR rate decreased from 40 to 8% after anti-CD25 monoclonal induction. Patient actuarial survival rate at 1, 3 and 5 yr was 100% for LD and 96% for DD. The overall actuarial graft survival at 1,3, and 5 yr was 96.7, 96.7 and 71% for LD and 89, 76 and 73% for DD donors. Graft survival rate improved from the first period (1989-2000) to the second period (2001-2003; p = 0.05). No difference in graft survival rate with HLA-A,B,DR matching was found. Graft survival rate was better when cold ischemia time was <24 h (p < 0.01). CMV infections increased from 19 to 40% when MMF and anti-CD25 Ab were introduced (p < 0.01). The height/age Z score at 1, 3 and 5 yr post-transplant was -2.2, -2.1, -2.2, respectively, for children older than 7 yr and -1.8, -1.9, -2.1 for those transplanted younger than 7 yr of age who were switched to alternate day steroids (p < 0.01). The cause of graft lost was: chronic rejection eight, non-adherence four, AR four and vascular thrombosis two. The cause of death in two patients was fungus septicemia and accelerated rejection. Pediatric renal transplantation can be performed in our group with acceptable morbidity, low mortality and graft survival rates similar to other reports in North America and Western Europe. Graft survival rate improved with newer immunosuppression and greater experience at the center. Management of non-adherence and chronic rejection remain the major challenges.

Kt/V and nPNA in pediatric peritoneal dialysis: a clinical or a mathematical association?

The relationship between dialysis dose and nutrition is a field of particular interest in chronic pediatric dialysis (PD), and a positive correlation between ureaKt/V and nPNA has been published, suggesting a better nutritional status is associated with higher dialysis doses. However, this relationship has also been criticized as being the result of a mathematical coupling resulting from the same variables. The objective of the study was to establish the relationship between dialysis dose (Kt/V) and nutritional variables: daily protein intake (DPI), protein catabolic rate (PCR), protein equivalent of total nitrogen appearance (PNA) and nitrogen balance (NB) in dialyzed children. A cohort, prospective, observational study was carried out, for which 223 biochemical measurements were performed in 20 patients, ages 1 month to 14.3 years old (13 males), under PD for a 12-month period of follow-up. Monthly residual and total ureaKt/V, DPI, PCR, nPNA and NB were calculated, and the correlation between Kt/V and the nutritional parameters was evaluated. The Borah equation was used to calculate the nPNA. The data are reported as the mean plus or minus the standard error. All statistical comparisons were done with a paired t test, and two-way ANOVA for repeated measures was used to calculate correlations. A P <0.05 was considered significant. Mean total and residual Kt/V was 3.4+/-1.3 and 1.69+/-1.27, respectively; nPNA and PCR were 1.38+/-0.44 and 1.39+/-0.43 g/kg/day, daily protein intake (DPI) was 3.25+/-1.27 g/kg/day, and NB showed a value of 1.86+/-1.25 g/kg/day. A significant positive correlation was found between Kt/V and DPI, PCR, DPC and nPNA (all values P <0.0001), but no correlation was found between total and residual Kt/V vs. nitrogen balance ( P:ns). Total Kt/V showed a significant positive correlation with nPNA, but it did not show any correlation with nitrogen balance, suggesting that the relationship with nPNA is the result of a mathematical association calculated from the same variables.

Total carnitine and acylated carnitine ratio: relationship of free carnitine with lipid parameters in pediatric dialysis patients

Carnitine has an essential role in the mitochondrial oxidation of long-chain fatty acids. Carnitine deficiency has been described in patients with chronic kidney disease. Total carnitine (TC) deficiency or a lower-than-normal ratio of free carnitine to acylated carnitine (FC:AC) has been shown to be associated with disorders in metabolism and plasma lipids. Metabolism and therapeutic use of carnitine have therefore been a major area of interest in dialysis patients. In a prospective observational study, we determined carnitine status (TC and FC:AC) and its correlations with lipid plasma levels in peritoneal dialysis (PD) and hemodialysis (HD) patients. In pediatric patients on chronic PD or HD, we evaluated nutritional status (weight and height), biochemical parameters (TC, FC, and AC levels), and fasting plasma lipoprotein concentrations. We studied 35 patients (16 boys, 19 girls; 25 on PD, 10 on HD). Median age was 5 years (range: 3 months-15 years). Median weight-to-height Z-score was -0.5 (range: -2.1 to 1.9), and median height-to-age Z-score was -2.5 (range: -0.3 to -2.9). The mean TC was 65.4 +/- 23.8 pg/mL (normal value: 40-55 pg/mL); the median AC was 18 pg/mL (range: 2-56pg/mL; normal value: 3-15 pg/mL); and the mean FC was 41.8 +/- 16.6 pg/mL (normal value: 25-35 pg/mL). Median serum FC:AC was 2.22 (range: 0.59-4.3; normal value: 4). A significantly higher AC and a lower FC:AC were observed in HD patients as compared with PD patients. No differences in TC and FC were observed when patients were grouped by dialysis modality, time on dialysis, or nutrition status. Total cholesterol was 200 mg/dL or higher in 20 patients, and 25 patients showed elevated triglycerides (> 150 mg/dL). The latter patients had a higher AC than did the group of patients with triglycerides below 150 mg/dL (AC: 22 pg/mL and 12.5 pg/mL respectively; Kruskal-Wallis p < 0.003). We found TC levels to be high in this group of patients. However, the FC:AC ratio was lower than normal in all except in 1 patient. Elevated triglycerides were associated with elevated AC, suggesting carnitine insufficiency in our patients.

[Dialysis dose, nutrition and growth among pediatric patients on peritoneal dialysis]

BACKGROUND

Stunting is common among pediatric patients on peritoneal dialysis.

AIM

To establish the best profile for urea kinetic variables associated to growth in children on chronic peritoneal dialysis (PD).

PATIENTS AND METHODS

Twenty patients, aged 1 month to 14 years, 13 males, were followed for 6-12 months, with monthly measurements of weight/age and height/age Z score; plasma creatinine, BUN, protein and albumin and urine and dialysate urea nitrogen, creatinine, protein and albumin. Minimum total Kt/V was 2.1. Dialysis dose (Kt/V), Protein Equivalent of Urea Nitrogen Appearance (PNA), Protein Catabolic Rate (PCR) and Nitrogen Balance (NB) were calculated. To identify the variable(s) associated to growth, the Tree Classification Model (CART) Enterprise Miner 8.1 was applied.

RESULTS

Mean total/residual Kt/V: 3.4+/-1.3/1.69+/-1.27; Daily Protein Intake (DPI) was 3.25+/-1.27 g/kg/day. nPNA, PCR and NB were 1.37+/-0.44, 0.84+/-0.33 and 1.86+/-1.25 g/kg/day, respectively. Mean height/age Z score was -2.3+/-1.19. Eleven patients showed a positive height/age delta Z (mean 0.55+/-0.38) and nine showed a negative growth (mean -0.50+/-0.42). The main variable explaining the positive growth was a Nitrogen Balance between 0.54 and 2.37 g/kg/day, mean 1.55+/-0.21 (p <0.001). The second associated variable to growth was a residual Kt/V between 0.43 and 4.6 (2.02+/-0.49) (p <0.05). Kt/V and nPNA showed a significant correlation, but no correlation could be found between Kt/V and NB.

CONCLUSIONS

Nitrogen Balance was the main variable associated to growth in pediatric PD, with values between 0.53 to 2.38 g/kg/day. The second variable was a residual Kt/V between 0.43 and 4.6. Therapy should be reassessed with NB values less than 0.54 or above 2.37 g/kg/day.

Comparison of Cyclosporine Concentrations 2 Hours Post-Dose Determined Using 3 Different Methods and Trough Level in Pediatric Renal Transplantation

Immunosuppression has been one of the great challenges in pediatric recipients of kidney allografts. Cyclosporine (CsA) has evolved during the past 25 years of transplantation. It requires frequent blood level monitoring because of its narrow therapeutic window and interpatient and intrapatient variability. Neoral (Novartis) is no exception. Ideally, monitoring of blood levels should also include determination of the area under the time-concentration curve (AUC) to better target the therapeutic window, thus avoiding underdosing or overdosing, especially in pediatric patients. A single blood concentration measurement 2 hours after Neoral administration (C2) has been shown to be a more for accurate predictor of drug exposure than trough levels (C0). Therefore, its use may lead to reduction in the incidence and severity of cellular rejection and of CsA toxicity. Some studies have shown that the metabolites/CsA ratio is substantially lower using C2 than C0, however, the between-assay differences for C2 monitoring have not been considered. The purpose of this study was to evaluate CsA C0 and C2 levels, determined using monoclonal fluorescence polarization immunoassay (FPIA)/TDx and enzyme multiplied immunoassay (EMIT). CsA levels were determined using a radioimmunoassay (RIA) in 30 pediatric transplant recipients with stable renal function within 42.7 mean months follow-up. Mean age was 13.4 years; 15 children were girls; 23 patients were recipients of cadaveric kidneys. The mean CsA microemulsion dose was 5.7 mg/kg/d. The 3 methods showed a high correlation between C0 and C2 (r > or = 0.97). A linear regression slope was significantly higher for C0 than C2 (P < .001). The CsA concentrations both at C0 and C2 were significantly higher with FPIA than with RIA (P < .009) but no differences were found for EMITT (P = .2). The mean C0 level for FPIA was 22% and 26% higher than RIA and EMIT, respectively. The mean C2, for FPIA was 7% and 12% higher than RIA and EMIT, respectively. In conclusion, CsA levels determined using RIA or EMIT are better than using FPIA/Tx; also, C2 CsA levels are more accurate than C0 in pediatric transplantation patients.