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.

[Type 1 diabetes mellitus and Graves Basedow's disease, a case of Autoimmune Polyglandular Syndrome]. / Diabetes mellitus tipo 1 y enfermedad de Graves Basedow, un caso de Síndrome Poliglandular Autoinmune.

INTRODUCTION: Type 1 diabetes mellitus (T1DM) is one of the most frequent autoimmune diseases in childhood. Its diagnosis requires the search for other autoimmune diseases. OBJECTIVE: to present the case of a pediatric patient with two rare concomitant autoimmune endocrine diseases. CLINICAL CASE: A 12-year-old male with no significant morbid history, is hospitalized due to a 3-month clinical pic ture of fatigue, eye pain, intermittent eyelid edema, goiter, polyphagia, polydipsia, polyuria, and weight loss (12 kilograms), compatible with T1DM and Graves-Basedow disease. It was confir med by laboratory tests which showed elevated glycemia (207 mg/dL, HbA1C 10.9%), suppressed TSH (< 0.01 uIU/mL), elevated FT4 (6.99 ng/dL), and the presence of anti-autoantibodies thyroid peroxidase, antithyroglobulin, and anti-TSH receptor, along with suggestive ultrasound findings. Therefore, we established the diagnosis of autoimmune polyglandular syndrome (APS) 3A and initiated treatment with insulin, propranolol, and thiamazole. The patient evolved satisfactorily and was discharged with outpatient follow-up. CONCLUSION: We present the case of an adolescent who presented APS due to T1DM and hyperthyroidism. This APS may be more common than is reported in clinical practice. The alteration of two or more endocrine glands or other autoimmune diseases should make us suspect its diagnosis, with important clinical implications, such as co morbidity and quality of life prognosis.

Identificación de variantes del gen NPHS2 en niños con síndrome nefrótico corticorresistente / NPHS2 Mutation analysis study in children with steroid-resistant nephrotic syndrome

Resumen: La podocina es una proteína localizada en el diafragma de filtración glomerular donde participa en la regulación de la filtración glomerular. Las mutaciones del gen NPHS2, que codifica a la podocina, son la principal causa de síndrome nefrótico corticorresistente (SNCR) autosómico recesivo en niños. Objetivos: Identificar mutaciones de NPHS2 en niños chilenos con SNCR, y establecer la prevalencia de las variantes más frecuentes en un grupo de adultos sanos. Pacientes y método: Análisis mutacional de NPHS2 en 34 niños chilenos con SNCR. Una vez identificadas las dos variantes de NPHS2 de mayor frecuencia, se realizó un screening de estas mutaciones en 223 adultos sanos. El análisis mutacional se realizó por secuenciación directa de los ocho exones codificantes amplificados por reacción de polimerasa en cadena. La secuenciación del DNA se realizó mediante método fluorométrico y las secuencias fueron evaluadas con el software SeqPilot. La asociación entre la presencia de variantes de NPHS2 y SNCR se calculó comparando las frecuencias alélicas entre los pacientes con SNCR y los voluntarios sanos utilizando prueba exacta de Fisher. Se consideró significativo p < 0,05. Resultados: Se detectaron mutaciones patogénicas de NPHS2 en siete de los 34 pacientes (21%) estudiados, de los cuales seis resultaron heterocigotos para p.R229Q y p.A284 V. En voluntarios sanos la prevalencia de p.R229Q fue de 2,46%. Conclusiones: Este estudio muestra que p.R229Q y p.A284 V son las variantes de NPHS2 más frecuentes en niños chilenos con SNCR. Por primera vez se describe esta asociación en niños chilenos, en base a la cual es posible proponer una estrategia de screening para estudio genético en pacientes con SNCR y sus familias. Se propone una estrategia de búsqueda de p.R229Q y p.A284 V en forma paralela o secuencial en estos pacientes.

Abstract: Podocin is a protein located in the glomerular slit diaphragm where it takes part in the regulation of glomerular filtration. Mutations of the NPHS2 gene that codes podocin are the main cause of autosomal recessive steroid resistant nephrotic syndrome (SRNS). Objectives: To identify the NPHS2 mutations in Chilean children with SRNS, and to determine the prevalence of the most common variants in a group of healthy adults. Patients and methods: Mutation analysis of NPHS2 in 34 Chilean children with SRNS. Once the two most common variants of NPHS2 were identified, screening for these mutations was performed on 233 healthy adults. The mutation analysis was performed by the direct sequencing of the eight coding exons by polymerase chain reaction amplification. The DNA sequencing was performed using a fluorometric method, and then evaluated with SeqPilot™ software. The relationship between the presence of NPHS2 variants and SRNS was calculated by comparing the allele frequency between patients with SRNS and those of the healthy volunteers using the exact Fisher test. A P < .05 was considered significant. Results: Pathogenic NPHS2 mutations were detected in 7 (21%) of the 34 patients studied, of which 6 were heterozygotes for p.R229Q and p.A284 V. The presence of p.R229Q was 2.46% in the healthy volunteers. Conclusions: This study shows that p.R229Q and p.A284 V are the most frequent variants in Chilean children with SRNS. It is the first time that this relationship has been reported in Chilean children. Based on this, a screening strategy is proposed for the genetic study in patients with SRNS and their families. A parallel or sequential search strategy for p.R229Q and p.A284 V in these patients is proposed.

Impaired phosphorylation of JAK2-STAT5b signaling in fibroblasts from uremic children.

BACKGROUND: Chronic kidney disease (CKD) in children is characterized by severe growth failure. The growth hormone/insulin-like growth factor-1 (GH/IGF-1) axis in uremic animals shows a post-receptor impaired phosphorylation of Janus kinase 2/signal transducer and activator of transcription (JAK-STAT) proteins. The objective of our study was to characterize the intracellular phosphorylation of JAK-STAT signaling in fibroblasts from children with CKD on chronic peritoneal dialysis (PD). METHODS: Serum GH-binding protein (GHBP), IGF-1 and IGFBP3 were measured in 15 prepubertal CKD stage-5 children on PD. Cytoplasmic JAK2, cytoplasmic/nuclear STAT5b and nuclear IGFBP3, acid-labile subunit (ALS) and IGF-1 mRNA expression were quantified in fibroblasts obtained from skin biopsies before and after stimulation with 200 ng/ml recombinant human growth hormone (rhGH). Phosphorylation activity at both the cytoplasmic and nuclear level was expressed as the ratio phosphorylated (p)/total (t) abundance of the product (p/t) at 30 and 60 min. Fifteen healthy children were recruited as the control group. Values were expressed in arbitrary units (AU) and normalized for comparison. Significance was defined as p < 0.05. RESULTS: Thirty minutes after rhGH stimulus, the cytoplasmic (p/t) JAK2 ratio was significantly lower in patients than in controls [median and interquartile range (IQR): 7.4 (4.56) vs. 20.5 (50.06) AU]. At 60 min after rhGH stimulation, median JAK2 phosphorylation activity was still significantly lower in the patients [7.14 (IQR 3.8) vs. 10.2 (IQR 29.8) AU; p < 0.05]. The increase in the cytoplasmic (p/t) STAT5b/ß-actin ratio was lower at both measurement points in the patients compared to the controls, without reaching statistical significance between groups. Median IGFBP3 mRNA abundance was significantly decreased in fibroblasts from uremic patients 24 h after rhGH stimulation compared to the healthy controls [1.27 (IQR 0.83) vs. 2.37 (IQR 0.80) AU]. Median ALS and IGF-1 mRNA expression changed in response to rhGH stimuli at 24 and 48 h. CONCLUSION: In this study, children with CKD undergoing PD therapy showed an impaired phosphorylation of JAK2/STAT5b signaling in fibroblasts after GH stimulation, as well as impaired IGFBP3 mRNA abundance. Both impairments may be partially responsible for the observed resistance to the growth-promoting actions of GH in chronic kidney failure.

[NPHS2 Mutation analysis study in children with steroid-resistant nephrotic syndrome]. / Identificación de variantes del gen NPHS2 en niños con síndrome nefrótico corticorresistente.

UNLABELLED: Podocin is a protein located in the glomerular slit diaphragm where it takes part in the regulation of glomerular filtration. Mutations of the NPHS2 gene that codes podocin are the main cause of autosomal recessive steroid resistant nephrotic syndrome (SRNS). OBJECTIVES: To identify the NPHS2 mutations in Chilean children with SRNS, and to determine the prevalence of the most common variants in a group of healthy adults. PATIENTS AND METHODS: Mutation analysis of NPHS2 in 34 Chilean children with SRNS. Once the two most common variants of NPHS2 were identified, screening for these mutations was performed on 233 healthy adults. The mutation analysis was performed by the direct sequencing of the eight coding exons by polymerase chain reaction amplification. The DNA sequencing was performed using a fluorometric method, and then evaluated with SeqPilot software. The relationship between the presence of NPHS2 variants and SRNS was calculated by comparing the allele frequency between patients with SRNS and those of the healthy volunteers using the exact Fisher test. A P<.05 was considered significant. RESULTS: Pathogenic NPHS2 mutations were detected in 7 (21%) of the 34 patients studied, of which 6 were heterozygotes for p.R229Q and p.A284V. The presence of p.R229Q was 2.46% in the healthy volunteers. CONCLUSIONS: This study shows that p.R229Q and p.A284V are the most frequent variants in Chilean children with SRNS. It is the first time that this relationship has been reported in Chilean children. Based on this, a screening strategy is proposed for the genetic study in patients with SRNS and their families. A parallel or sequential search strategy for p.R229Q and p.A284V in these patients is proposed.

Longitudinal FGF23 and Klotho axis characterization in children treated with chronic peritoneal dialysis.

BACKGROUND: Fibroblast Growth Factor-23 (FGF23) and cofactor Klotho are key regulators of mineral metabolism in chronic kidney disease (CKD), but little is known about the mechanisms that regulate their production. This study evaluates longitudinal changes of FGF23 and Klotho levels and their regulatory factors in children on chronic peritoneal dialysis (PD). METHODS: FGF23, Klotho, 25(OH) vitamin D, 1,25-dihydroxyvitamin D and parathyroid hormone (PTH) plasma concentrations were measured during 1 year of follow-up in PD children. Anthropometric and dialytical parameters were evaluated in addition to mineral metabolism variables. RESULTS: Thirty-one patients under chronic PD were followed for 12 months. FGF23 mean plasma levels at Month 1 were significantly increased compared with controls, 215.1 ± 303.6 versus 9.4 ± 5.7 pg/mL, respectively (P < 0.001). Baseline Klotho levels were 41% lower in patients compared with controls, 132.1 ± 58 versus 320 ± 119.4 pg/mL, respectively (P < 0.001), and did not correlate with FGF23 and phosphorus levels. At Month 12, FGF23 (195 ± 300 pg/mL) and Klotho levels (130 ± 34 pg/mL) remained similar to baseline values. Log-FGF23 correlated significantly with height/age Z score (r= -0.38) and residual renal function (r = -0.44), but no correlation was found with serum phosphorus, phosphate intake, PTH and vitamin D levels. The log-FGF23 strongly correlated with calcium levels at Months 1, 6 and 12, however, this relationship was blunted if serum phosphorus was >6 mg/dL. By multiple regression analysis, calcium was the strongest variable determining FGF23 levels. CONCLUSIONS: In this longitudinal study, FGF23 levels are markedly increased, and Klotho levels are reduced in PD children compared with controls. FGF23 levels appeared to be regulated primarily by serum calcium, showing a significant correlation at each time of measurement. This relationship was lost in patients with phosphorus >6 mg/dL. These observations may have important consequences to the therapeutic management of phosphate homeostasis in CKD patients.

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.

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.

[Hypovitaminosis D in pediatric patients on renal replacement therapy]. / Hipovitaminosis D en pacientes pediátricos en terapia de sustitución renal.

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.

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.

Continuous EPO receptor activator therapy of anemia in children under peritoneal dialysis.

The short half-life of erythropoietin (rHuEPO) leads to repeated fluctuations in hemoglobin levels and the need for frequent administration. Continuous erythropoietin receptor activator (CERA) therapy has been approved for once or twice a month in adult dialysis patients. To evaluate the efficacy and safety of CERA therapy in the management of anemia in pediatric peritoneal dialysis (PD) stable PD children under twice-a-week EPO were converted to a subcutaneous CERA, scheduled every 2 weeks. The follow-up was 6 months. The primary efficacy parameter was hemoglobin > 11 g/dL. The exclusion criteria were ferritin <100 ng/ml and Hb saturation <20%. Sixteen children, aged 9.75 ± 3.6 years, including 11 boys, participated in the study. Mean Hb level at month 0 was 10.8 ± 1.9 g/dL. A decrease in hemoglobin to 10.38 ± 1 g/dL at month 2 was observed. The CERA dose was increased from 0.86 ± 0.33 to 1.67 ± 0.4 µg/kg at month 3. The target Hb level was reached by the 3rd month. The Hb level and CERA dose were 12.2 ± 1.2 and 1.6 ± 0.67 µg/kg respectively at the end of the study. No adverse events were observed during the protocol. CERA is an effective and safe therapy for maintaining hemoglobin levels when administered twice, up to once a month, in PD children. Doses required to reach target Hb were higher than published experiences in adult populations.

Hipovitaminosis D en pacientes pediátricos en terapia de sustitución renal / 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 percent 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.

Intraperitoneal calcitriol in infants on peritoneal dialysis.

BACKGROUND: Calcitriol has long been used as the main therapy in renal osteodystrophy, but the efficacy of the oral route is not always as high as expected. OBJECTIVE: To asses the safety and efficacy of intraperitoneal calcitriol in infants undergoing peritoneal dialysis (PD). PATIENTS AND METHODS: PD patients on oral calcitriol therapy, with serum parathyroid hormone (PTH) >1000 pg/mL during the previous 3 months of treatment, were switched to intraperitoneal calcitriol therapy, 1 microg twice per week. Dose was increased to 1 microg three times per week if PTH remained >1000 pg/mL, and was later readjusted. Target PTH was 200-300 pg/mL according DOQI guidelines. STATISTICS: All results are expressed as mean +/- SE. The Wilcoxon signed rank test was used to evaluate differences in measurements for each pair of values. The confidence interval for differences between population medians was 96.9%. A p value less than 0.05 was considered significant. RESULTS: Six male children, mean age 17 +/- 3.86 months, completed a 12-month follow-up. Mean pretreatment PTH was 1654 +/- 209 pg/mL. Mean PTH at months 0, 3, 6, 9, and 12 was 1448 +/- 439*, 1277 +/- 723, 910 +/- 704, 582 +/- 282*, and 465 +/- 224* pg/mL, respectively (*p < 0.05). Twelve hypercalcemic and 10 hyperphosphatemic episodes were successfully treated. CONCLUSION: Infants on PD who fail to respond to oral calcitriol therapy can be safely treated with intraperitoneal administration of active vitamin D.

[Dialysis dose, nutrition and growth among pediatric patients on peritoneal dialysis]. / Dosis de diálisis, nutrición y crecimiento en diálisis peritoneal pediátrica.

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.

Body composition in children on peritoneal dialysis.

Dual-energy X-ray absorptiometry (DEXA) can be used to evaluate total-body bone mineral content (BMC), bone mineral density (BMD), fat-free mass (FFM), and fat body mass (FBM), which are all frequently affected in patients (PD) on peritoneal dialysis. We used DEXA to evaluate body composition in children on PD and to establish whether relationships existed with nutrition status, dialytic parameters, and biochemical data. We evaluated 20 PD patients (12 boys, 8 girls). The mean age of the patients was 5.84 years (range: 0.16- 14.66 years). We carried out DEXA, anthropometry (weight/age, height/age, and body mass index), and measurements of dietary intake (protein, energy, calcium, and phosphorus), nitrogen balance (NB), dialysis dose (Kt/V), peritoneal equilibrium test (PET), and plasma calcium, phosphorus, and bicarbonate at months 1 and 6 of the study. Energy intake was prescribed according to the United States Recommended Dietary Allowances, and Kt/V and daily protein intake (DPI) according to the Dialysis Outcomes Quality Initiative (DOQI) guidelines. In the patients, BMD increased to 0.769 +/- 0.174 g/ cm2 from 0.747 +/- 0.166 g/cm2 (p < 0.05), and BMC increased to 680.3 +/- 666.1 g from 632.6 +/- 597.5 g (p < 0.01). The mean BMD Z score for patients older than 4 years (n = 11) was -0.69 at month 1, with a significant increase to -0.35 at month 6. The FBM and FFM increased, but without reaching statistical significance. At months 1 and 6, the DPI was 144.3% and 129.9% respectively (p = nonsignificant) and showed a negative correlation with BMD, BMC, and FFM (p < 0.05). Comparing DPI to plasma bicarbonate showed a negative correlation at month 1 (p < 0.05). Negative correlations were also found between NB and the parameters BMD, FBM, and FFM (p < 0.05). be content All patients showed a positive NB. No correlation was found between DEXA and anthropometric measurements, energy intake, serum calcium, serum phosphorus, or Kt/V Dialysate-to-plasma creatinine from the PET showed a negative correlation with BMD and FFM (p < 0.05). In terms of positive NB and controlled Kt/V we observed an increase in bone mineralization within the 6 months offollow-up. A high protein intake seems to negatively affect acid-base status, bone mineralization, and FFM.

Renal osteodystrophy in pediatric patients on peritoneal dialysis.

Renal osteodystrophy (ROD) is one of the mostfrequent complications in pediatric uremic patients on peritoneal dialysis (PD), and each case requires a different therapeutic approach. In the present study, we characterized ROD in pediatric patients on chronic PD. We studied 20 patients (12 boys, 8 girls) for a 12-month period. The mean age of the patients was 5.82 +/- 5 years. We allocated each patient to one of three groups according to intact parathormone (iPTH) value: group 1, iPTH < or = 150 pg/mL, n = 12; group 2, iPTH 151 - 400 pg/mL, n = 2; and group 3, iPTH > or = 401 pg/mL, n = 6. Monthly, we recorded plasma calcium, phosphorus, and alkaline phosphatase; Kt/V; normalized protein equivalent of total nitrogen appearance (nPNA); and calcitriol dose. Growth was registered as the Z height/age. Student t-test and analysis of variance for repeated measures were used for the statistical analyses. A value of p < 0.05 was considered significant. All 20 patients completed 6 months of follow-up; 9 patients completed 12 months. At months 1, 6, and 12, vitamin D doses for groups 1 and 3 were significantly different (p < 0.05), as expected. Mean values of iPTH for groups 1 and 3 were 52 +/- 47 pg/mL and 1239 +/- 718 pg/mL respectively, p < 0.05. At 6 months' follow-up, iPTH values had changed to 163 +/- 177 pg/mL for group 1 and 544 +/- 249 pg/mL for group 3 (p < 0.05), butfor group 3 that trend was lost at 12 months' follow-up, when their mean iPTH value rose to 972 +/- 420 pg/mL. Patients who had been started on PD less than 6 months before entering the study (60% of patients) showed a mean iPTH value of 629.13 pg/mL. Patients with more than 6 months on dialysis before entering the study showed an iPTH value of 115.53 pg/mL (p < 0.05). At 6 months' follow-up, iPTH values in groups 1 and 3 both showed a change toward the value range for group 2. At month 12, iPTH values in group 1 continued to show the same tendency, but iPTH values in group 3 showed a tendency to return to their initial levels. Low-turnover ROD was highly prevalent in the study, correlating strongly with time on dialysis.

Adequacy and nutrition in pediatric peritoneal dialysis.

Outcomes for pediatric peritoneal dialysis (PD) patients are closely related to dialysis adequacy and nutrition, which need to be measured frequently using a number of laboratory parameters. Although the critical meaning of adequacy and nutrition in the long-term prognosis of dialyzed children is well-documented, PD prescriptions are still largely empirical. Our objective was to evaluate nutritional and dialytic parameters in PD children (urea, creatinine, and albumin excretion in dialysate and urine, and daily protein intake); to measure peritoneal equilibration test (PET) results, Kt/V, normalized equivalent of protein nitrogen appearance (nPNA) and nitrogen balance; and to study the correlations between those variables. We performed 59 prospective laboratory measurements in 15 stable PD patients (7 boys; mean age: 6.7 years; age range: 1.1-14.8 years) during 6 months of follow-up. Creatinine, urea, total protein, and albumin were measured in plasma, urine, and dialysate. We calculated PET, Kt/V, daily dietary protein intake (DPI), protein catabolic rate (PCR), and nPNA. All statistical comparisons used the paired t-test, and correlations were calculated by two-way analysis of variance for repeated measures. A value of p < 0.05 was considered significant. The mean 4-hour dialysate-to-plasma ratio (D/P) of creatinine was 0.78 +/- 0.02 at month 0 and 0.74 +/- 0.13 at month 6 [p = nonsignificant (NS)]. The mean final-dialysate-to-initial-dialysate ratio (D/D0) of glucose was 0.35 +/- 0.11 and 0.34 +/- 0.08 at the same intervals (p = NS). The D/P creatinine showed an inverse correlation with patient age and body surface area, and the D/D0 glucose ratio showed a positive correlation with both of those parameters (p < 0.05). Weekly total and residual Kt/V urea were 3.41 +/- 0.86 and 1.49 +/- 1 respectively. The daily DPI was 3.32 +/- 1.05 g/kg, and the daily PCR was 1.32 +/- 0.47 g/kg, showing a positive net protein balance (DPI-PCR = +2 g/kg daily), which was negatively correlated with age and body surface area (p < 0.001). The mean daily nPNA was 0.94 +/- 0.33 g/kg, which was negatively correlated with age and body surface area (p < 0.05, r = -0.51), and positively correlated with daily DPI and total and residual Kt/V (p < 0.0001). Our patients could be classified as high-average transporters, with low-average ultrafiltration. The high transport state was associated with greater peritoneal albumin losses, a point of concern at younger ages. Total Kt/V and nPNA were higher for the youngest patients, suggesting a favorable nutrition status, but more studies are needed to determine the best value for both parameters in clinical practice.