Frecuencia de mutaciones encontradas en niños con enfermedad renal crónica por síndrome nefrótico cortico-resistente / Frequency of mutations found in children with chronic kidney disease due to steroid-resistant nephrotic syndrome

RESUMEN La enfermedad renal crónica en niños puede tener como etiología un grupo cuya causa genética, incluye las anomalías congénitas del riñón y las vías urinarias y las nefropatías hereditarias. Objetivo: Describir la frecuencia de mutaciones en niños con síndrome nefrótico corticoresistente (SNRE). Material y métodos: Estudio multicéntrico, tipo serie de casos, realizado en niños con SNRE, mediante el resultado de secuenciamiento directo de los genes; NPHS1, NPHS2, NPHP1 y WT1. Resultados: Se enrolaron 33 pacientes pediátricos con enfermedad renal crónica, 45,5% mujeres, edad promedio 13±7 años, 78,8% de raza mestiza, 24,2% consanguíneos, 60,6% se encontraban en hemodiálisis, 72,7% presentaban síndrome nefrótico cortico resistente y de ellos 8/24 (33,3%) presentó al menos una mutación en los genes; WT1, NPHS1, NPHP1y NPHS2 siendo la frecuencia de estas mutaciones de 37,5% (3/8), 25% (2/8), 25% (2/8) y 12,5% (1/8), respectivamente. Conclusiones: El 33,3% de los pacientes pediátricos con enfermedad renal crónica con síndrome nefrótico corticoresistente (SNRE) presentaron mutaciones, la más frecuente fue en el gen WT1.

SUMMARY Chronic kidney disease in children may be caused by a group of genetic abnormalities of the kidney, urinary tract and hereditary nephropathies. Objective: To report the frequency of mutations in children with steroid-resistant nephrotic syndrome (SRNS). Methods: A multicentric case series among children with SRNS identified through direct sequencing of NPHS1, NPHS2, NPHP1 and WT1 genes. Results: 33 children were enrolled; 45.5% were females; mean age was 13±7 years; 78.8% were mestizo: 24.2% consanguineous; 60.6% were receiving dialysis: 72.7% had SRNS and 8/24 (33.3%) of them presented at least one mutation to WT1, NPHS1, NPHP1 and NPHS2 genes. Corresponding values for these mutations were 37.5% (3/8), 25% (2/8), 25% (2/8) and 12.5% (1/8), respectively. Conclusions: 33% of pediatric patients with SRNS presented gene mutations, the most frequent of these mutations was WT1.

Outcomes of children with idiopathic steroid resistant nephrotic syndrome: a single centre observational study / Desfechos de crianças com síndrome nefrótica idiopática córtico-resistente: um estudo observacional de centro único

ABSTRACT Introduction: Idiopathic steroid resistant nephrotic syndrome (SRNS) has variable outcomes in children. The primary objective of the present study was to assess the cumulative remission rate and the secondary objectives were to assess factors affecting the remission status, kidney function survival, and adverse effects of medications. Methods: One hundred fourteen patients with SRNS were included. Calcineurin inhibitor-based treatment protocol along with prednisolone and angiotensin-converting enzyme inhibitor were used, and patients were followed over 5 years. Results: Median age was 4.5 years; 53.5% of cases were between 1 to 5 years of age. Sixty-two patients (54.4%) were at initial stage and 52 (45.6%) were at a late SRNS stage. Median eGFRcr was 83.5 mL/min/1.73m2 at presentation. Of the 110 patients, 63 (57.3%) achieved remission [complete remission 30 (27.3%), partial remission 33 (30%)], and 47 (42.7%) had no remission. Kidney function survival was 87.3% and 14 cases (12.7%) had progression to CKD (G3-8, G4-3, G5-1, and G5D-2). Median duration of follow up was 36 months (IQR 24, 60). Age of onset, cyclosporine/tacrolimus, eGFRcr, and histopathology (MCD/FSGS) did not affect remission. Similarly, remission status in addition to age of onset, drug protocol, and histopathology did not significantly affect kidney function during a period of 5 years. Hypertension, cushingoid facies, short stature, cataract, and obesity were observed in 37.7, 29.8, 25.5, 17.5, and 0.7% of cases, respectively. Conclusion: About half of the cases achieved remission. Age of onset of disease, cyclosporine/tacrolimus use, and histopathological lesion neither affected remission status nor short-term kidney function survival in SRNS.

RESUMO Introdução: A síndrome nefrótica idiopática córtico-resistente (SNICR) apresenta desfechos variáveis em crianças. O objetivo principal deste estudo foi avaliar a taxa de remissão cumulativa. Os objetivos secundários foram avaliar fatores que afetam status de remissão, sobrevida da função renal e efeitos adversos de medicamentos. Métodos: Foram incluídos 114 pacientes com SNCR. Utilizou-se protocolo de tratamento baseado em inibidores de calcineurina juntamente com prednisolona e inibidor da enzima conversora de angiotensina. Os pacientes foram acompanhados durante 5 anos. Resultados: A idade mediana foi 4,5 anos; 53,5% dos casos tinham entre 1 e 5 anos. 62 pacientes (54,4%) estavam em estágio inicial; 52 (45,6%) em estágio tardio da SNCR. A TFGecr mediana foi 83,5 mL/min/1,73 m2 na apresentação. Dos 110 pacientes, 63 (57,3%) alcançaram remissão [remissão completa 30 (27,3%), remissão parcial 33 (30%)], e 47 (42,7%) não apresentaram remissão. A sobrevida da função renal foi 87,3%; 14 casos (12,7%) progrediram para DRC (G3-8, G4-3, G5-1, G5D-2). A duração mediana do acompanhamento foi 36 meses (IIQ 24, 60). Idade no início, ciclosporina/tacrolimus, TFGecr e histopatologia (DLM/GESF) não afetaram a remissão. Igualmente, status de remissão, além da idade no início, protocolo de medicamentos e histopatologia não afetaram significativamente a função renal por 5 anos. Observou-se hipertensão, fácies cushingoide, baixa estatura, catarata e obesidade em 37,7; 29,8; 25,5; 17,5; e 0,7% dos casos, respectivamente. Conclusão: Aproximadamente metade dos casos alcançou remissão. Idade no início, uso de ciclosporina/tacrolimus e lesão histopatológica não afetaram o status de remissão nem a sobrevida da função renal a curto prazo na SNICR.

Nephrotic Syndrome and Renin-angiotensin System: Pathophysiological Role and Therapeutic Potential.

Idiopathic Nephrotic Syndrome (INS) is the most frequent etiology of glomerulopathy in pediatric patients and one of the most common causes of chronic kidney disease (CKD) and end-stage renal disease (ESRD) in this population. In this review, we aimed to summarize evidence on the pathophysiological role and therapeutic potential of the Renin-Angiotensin System (RAS) molecules for the control of proteinuria and for delaying the onset of CKD in patients with INS. This is a narrative review in which the databases PubMed, Web of Science, and Sci- ELO were searched for articles about INS and RAS. We selected articles that evaluated the pathophysiological role of RAS and the effects of the alternative RAS axis as a potential therapy for INS. Several studies using rodent models of nephropathies showed that the treatment with activators of the Angiotensin-Converting Enzyme 2 (ACE2) and with Mas receptor agonists reduces proteinuria and improves kidney tissue damage. Another recent paper showed that the reduction of urinary ACE2 levels in children with INS correlates with proteinuria and higher concentrations of inflammatory cytokines, although data with pediatric patients are still limited. The molecules of the alternative RAS axis comprise a wide spectrum, not yet fully explored, of potential pharmacological targets for kidney diseases. The effects of ACE2 activators and receptor Mas agonists show promising results that can be useful for nephropathies including INS.

Promises and pitfalls of whole-exome sequencing exemplified by a nephrotic syndrome family.

High-throughput techniques such as whole-exome sequencing (WES) show promise for the identification of candidate genes that underlie Mendelian diseases such as nephrotic syndrome (NS). These techniques have enabled the identification of a proportion of the approximately 54 genes associated with NS. However, the main pitfall of using WES in clinical and research practice is the identification of multiple variants, which hampers interpretation during downstream analysis. One useful strategy is to evaluate the co-inheritance of rare variants in affected family members. Here, we performed WES of a patient with steroid-resistant NS (SRNS) and intermittent microhematuria. Currently, 15 years after kidney transplantation, this patient presents normal kidney function. The patient was found to be homozygous for a rare MYO1E stop-gain variant, and was heterozygous for rare variants in NS-associated genes, COL4A4, KANK1, LAMB2, ANLN, E2F3, and APOL1. We evaluated the presence or absence of these variants in both parents and 11 siblings, three of whom exhibited a milder phenotype of the kidney disease. Analysis of variant segregation in the family, indicated the MYO1E stop-gain variant as the putative causal variant underlying the kidney disease in the patient and two of her affected sisters. Two secondary variants in COL4A4-identified in some other affected family members-require further functional studies to determine whether they play a role in the development of microhematuria in affected family members. Our data illustrate the difficulties in distinguishing the causal pathogenic variants from incidental findings after WES-based variant analysis, especially in heterogenous genetic conditions, such as NS.

Niflumic Acid Reverses Airway Mucus Excess and Improves Survival in the Rat Model of Steroid-Induced Pneumocystis Pneumonia.

Although the role of adaptive immunity in fighting Pneumocystis infection is well known, the role of the innate, airway epithelium, responses remains largely unexplored. The concerted interaction of innate and adaptive responses is essential to successfully eradicate infection. Increased expression of goblet-cell-derived CLCA1 protein plus excess mucus in infant autopsy lungs and in murine models of primary Pneumocystis infection alert of innate immune system immunopathology associated to Pneumocystis infection. Nonetheless, whether blocking mucus-associated innate immune pathways decreases Pneumocystis-related immunopathology is unknown. Furthermore, current treatment of Pneumocystis pneumonia (PcP) relying on anti-Pneumocystis drugs plus steroids is not ideal because removes cellular immune responses against the fungal pathogen. In this study, we used the steroid-induced rat model of PcP to evaluate inflammation and mucus progression, and tested the effect of niflumic acid (NFA), a fenamate-type drug with potent CLCA1 blocker activity, in decreasing Pneumocystis-associated immunopathology. In this model, animals acquire Pneumocystis spontaneously and pneumonia develops owing to the steroids-induced immunodeficiency. Steroids led to decreased animal weight evidencing severe immunosuppression and to significant Pneumocystis-associated pulmonary edema as evidenced by wet-to-dry lung ratios that doubled those of uninfected animals. Inflammatory cuffing infiltrates were noticed first around lung blood vessels followed by bronchi, and both increased progressively. Similarly, airway epithelial and lumen mucus progressively increased. This occurred in parallel to increasing levels of MUC5AC and mCLCA3, the murine homolog of hCLCA1. Administration of NFA caused a significant decrease in total mucus, MUC5AC and mCLCA3 and also, in Pneumocystis-associated inflammation. Most relevant, NFA treatment improved survival at 8 weeks of steroids. Results suggest an important role of innate immune responses in immunopathology of steroid-induced PcP. They warrant evaluation of CLCA1 blockers as adjunctive therapy in this condition and describe a simple model to evaluate therapeutic interventions for steroid resistant mucus, a common condition in patients with chronic lung disease like asthma, chronic obstructive pulmonary disease (COPD) and cystic fibrosis.

Rituximab in The Management of Pediatric Steroid-Resistant Nephrotic Syndrome: A Systematic Review.

OBJECTIVES: To evaluate the efficacy and safety of rituximab in children with steroid-resistant nephrotic syndrome. STUDY DESIGN: A systematic review evaluating the efficacy and safety of rituximab in children with steroid-resistant nephrotic syndrome was performed. Data from studies, performed before April 2017 were collected, from MEDLINE, Cochrane Library, Scopus, and Web of Science. Study eligibility criteria included clinical trials and observational studies with a minimal sample size of 5 patients, regarding treatment with rituximab in children with steroid-resistant nephrotic syndrome. Independent extraction of articles by 2 investigators using predefined data fields was performed. RESULTS: We included 7 case series and 1 open-label randomized controlled trial. Among them, 3 studies were multicenter. A total of 226 patients were included. Mean age at onset was 5.6 ± 1.1 years. Mean number of rituximab administrations was 3.1 ± 1.1 infusions per patient. Remission was observed in 89 patients (46.4%). Remission was seen in 40.8% patients with initial steroid-resistant nephrotic syndrome and 52.8% patients with late steroid-resistant nephrotic syndrome. Good initial response to rituximab therapy was observed in 63.2% patients with minimal change nephrotic syndrome, 39.2% patients with focal and segmental glomerulosclerosis, 1 patient had diffuse mesangial hypercellularity, and 1 patient had IgM nephropathy. Sustained remission ranged from 18% to 93.7%. Five serious adverse events were observed. CONCLUSIONS: Rituximab exhibited a satisfactory profile regarding efficacy and safety indicating that this agent is a promising therapy for steroid-resistant nephrotic syndrome and should be further investigated by randomized clinical trials.

Hepatitis autoinmune refractaria: ¿cómo escoger el tratamiento de segunda línea o de rescate? / Refractory autoimmune hepatitis: how to choose second-line or rescue therapy?

Autoimmune hepatitis (AIH) is a liver disease of unknown etiology, with a breakdown in peripheral selftolerance against hepatocytes with both genetic and environmental factors involved. It is characterized by an immune mediated liver injury, with detectable autoantibodies, elevated levels of immunoglobulin G and histological criteria including, necroinflammation, lymphoplasmacytic infiltrates and hepatitis interface. It can be asymptomatic or can present as acute hepatitis or liver cirrhosis. Most patients (70-80%) respond to first line therapy (based on steroids ± azathioprine). In those patients not tolerating azatioprine, in steroid resistant, and those with repeated relapses (20-40%), a long-term second line therapy must be considered to avoid progression of liver disease. This last medications include other immunosuppressants like mycophenolate mophetil, calcineurin inhibitors (cyclosporine or tacrolimus), biologic agents (infliximab and rituximab), and other immunosuppressive agents (sirolimus, everolimus), all with good overall clinical results, but not exempt of side effects. Other difficult scenarios include fulminant AIH, end-stage AIH cirrhosis and the management of post-transplant AIH. In this article we will review the literature related to second- line therapy especially of steroid resistant AIH. Future directions in the treatment of HAI should be guided to the individual patient (personalized) and may include cell therapies, such as infusion of autologous, antigen-specific, and liver-homing regulatory T cells to restore hepatic immune tolerance

La hepatitis autoinmune (HAI) es una hepatopatía de etiología desconocida, con pérdida de la tolerancia inmune contra los hepatocitos con factores genéticos y ambientales asociados. Se caracteriza por fenómenos de daño inmunológicos, con autoanticuerpos circulantes, una concentración elevada de gammaglobulina sérica y en la biopsia de hígado actividad necroinflamatoria, infiltrados linfoplasmocitarios y daño de interfase. La HAI es una entidad que se puede presentar en forma asintomática, como hepatitis aguda o como cirrosis hepática. El 70-80% de los pacientes responden adecuadamente al tratamiento inmunosupresor de primera línea (corticoides ± azatioprina). En los pacientes que no toleran azatioprina, en los corticorresistentes o en aquellos con recaídas repetidas a pesar de terapia (20-40%), es necesario recurrir a terapias de segunda línea de largo plazo, para evitar la progresión de la hepatopatía. Estas últimas incluyen micofenolato mofetil, inhibidores calcineurínicos (ciclosporina o tacrolimus), agentes biológicos (infliximab y rituximab), y otros fármacos inmunosupresores (sirolimus, everolimus), con resultados alentadores, pero no exentos de efectos colaterales. Otros escenarios complejos incluyen: la HAI de presentación aguda grave y fulminante, la cirrosis terminal autoinmune y la HAI post-trasplante. En este trabajo se revisa la literatura en relación a terapias de segunda línea especialmente en HAI corticoide resistente. El futuro del tratamiento de la HAI va encaminado a una terapia personalizada y que podría incluir terapias celulares como la infusión de células T regulatorias, antígeno específicas y autólogas, para reestablecer los mecanismos de tolerancia inmune hepática.

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.

[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.

Síndrome nefrótico idiopático: recomendaciones de la Rama de Nefrología de la Sociedad Chilena de Pediatría. Parte 2 / Idiopathic Nephrotic Syndrome: recommendations of the Nephrology Branch of the Chilean Society of Pediatrics. Part two

El síndrome nefrótico idiopático es la glomerulopatía más frecuente en la infancia, afecta a 1-3/100 mil niños menores de 16 años y se presenta con más frecuencia entre los 2 y 10 años. Su causa es desconocida, y la mayoría de las veces responde a corticoides, con buen pronóstico a largo plazo. El síndrome nefrótico corticorresistente representa un 10-20% de los síndromes nefróticos idiopáticos en pediatría. Tiene mal pronóstico, y su manejo constituye un desafío terapéutico significativo. La mitad de los pacientes evoluciona a insuficiencia renal crónica terminal en un plazo de 5 años, estando expuestos además a las complicaciones secundarias a un síndrome nefrótico persistente y a efectos adversos de la terapia inmunosupresora. El objetivo fundamental del tratamiento es conseguir una remisión completa, pero una remisión parcial se asocia a una mejor sobrevida renal que la falta de respuesta. Este documento surgió de un esfuerzo colaborativo de la Rama de Nefrología de la Sociedad Chilena de Pediatría con el objetivo de ayudar a los pediatras y nefrólogos infantiles en el tratamiento del síndrome nefrótico idiopático en pediatría. En esta segunda parte, se discute el manejo del síndrome nefrótico corticorresistente, así como de las terapias no específicas.

Idiopathic nephrotic syndrome is the most common glomerular disease in childhood, affecting 1 to 3 per 100,000 children under the age of 16. It most commonly occurs in ages between 2 and 10. Its cause is unknown, and its histology corresponds to minimal change disease in 90% of cases, or focal segmental glomerulosclerosis. Steroid-resistant nephrotic syndrome represents 10-20% of idiopathic nephrotic syndrome in pediatrics. It has a poor prognosis, and its management is a significant therapeutic challenge. Half of patients evolve to end-stage renal disease within 5 years, and are additionally exposed to complications secondary to persistent NS and to the adverse effects of immunosuppressive therapy. The primary goal of treatment is to achieve complete remission, but even a partial remission is associated with a better renal survival than the lack of response. This paper is the result of the collaborative effort of the Nephrology Branch of the Chilean Society of Pediatrics with aims at helping pediatricians and pediatric nephrologists to treat pediatric idiopathic nephrotic syndrome. In this second part, handling of steroid-resistant nephrotic syndrome as well as nonspecific therapies are discussed.

[Idiopathic Nephrotic Syndrome: recommendations of the Nephrology Branch of the Chilean Society of Pediatrics. Part two]. / Síndrome nefrótico idiopático: recomendaciones de la Rama de Nefrología de la Sociedad Chilena de Pediatría. Parte 2.

Idiopathic nephrotic syndrome is the most common glomerular disease in childhood, affecting 1 to 3 per 100,000 children under the age of 16. It most commonly occurs in ages between 2 and 10. Its cause is unknown, and its histology corresponds to minimal change disease in 90% of cases, or focal segmental glomerulosclerosis. Steroid-resistant nephrotic syndrome represents 10-20% of idiopathic nephrotic syndrome in pediatrics. It has a poor prognosis, and its management is a significant therapeutic challenge. Half of patients evolve to end-stage renal disease within 5 years, and are additionally exposed to complications secondary to persistent NS and to the adverse effects of immunosuppressive therapy. The primary goal of treatment is to achieve complete remission, but even a partial remission is associated with a better renal survival than the lack of response. This paper is the result of the collaborative effort of the Nephrology Branch of the Chilean Society of Pediatrics with aims at helping pediatricians and pediatric nephrologists to treat pediatric idiopathic nephrotic syndrome. In this second part, handling of steroid-resistant nephrotic syndrome as well as nonspecific therapies are discussed.

Tratamiento del síndrome nefrótico idiopático en niños / Treatment of idiopathic nephrotic syndrome in children

La incidencia anual del síndrome nefrótico se ha estimado en 1-3 por cada 100,000 niños menores de 16 años de edad. En niños, la causa más común del síndrome nefrótico es el síndrome nefrótico idiopático (SNI), que se define por la presencia de proteinuria e hipoalbuminemia y es, por definición, una enfermedad primaria. En el estudio de la biopsia renal se pueden encontrar alteraciones histológicas renales no específicas que incluyen lesiones mínimas, glomeruloesclerosis segmentaria y focal y proliferación mesangial difusa. En todos los pacientes con SNI se indica el tratamiento con corticosteroides, ya que, habitualmente, no se requiere de una biopsia renal antes de iniciar el tratamiento. La mayoría de los pacientes (80-90%) responden a este tratamiento. Los niños con SNI que no presentan remisión completa con el tratamiento con corticosteroides generalmente presentan glomeruloesclerosis segmentaria y focal, y requieren tratamiento con inhibidores de calcineurina (ciclosporina o tacrolimus), mofetil micofenolato o rituximab, además del bloqueo del sistema renina-angiotensina. En este artículo se revisan las recomendaciones recientes aceptadas para el tratamiento de los niños con SNI.

The annual incidence of the nephrotic syndrome has been estimated to be 1-3 per 100,000 children < 16 year of age. In children, the most common cause of nephrotic syndrome is idiopathic nephrotic syndrome (INS). INS is defined by the presence of proteinuria and hypoalbuminemia and by definition is a primary disease. Renal biopsy study shows non-specific histological abnormalities of the kidney including minimal changes, focal and segmental glomerular sclerosis, and diffuse mesangial proliferation. Steroid therapy is applied in all cases of INS. Renal biopsy is usually not indicated before starting corticosteroid therapy. The majority of patients (80-90%) are steroid-responsive. Children with INS who do not achieve a complete remission with corticosteroid therapy commonly present focal and segmental glomerular sclerosis and require treatment with calcineurin inhibitors (cyclosporine or tacrolimus), mycophenolate mofetil or rituximab, plus renin-angiotensin system blockade. In this article we review the recent accepted recommendations for the treatment of children with INS.

[Treatment of idiopathic nephrotic syndrome in children]. / Tratamiento del síndrome nefrótico idiopático en niños.

The annual incidence of the nephrotic syndrome has been estimated to be 1-3 per 100,000 children<16 year of age. In children, the most common cause of nephrotic syndrome is idiopathic nephrotic syndrome (INS). INS is defined by the presence of proteinuria and hypoalbuminemia and by definition is a primary disease. Renal biopsy study shows non-specific histological abnormalities of the kidney including minimal changes, focal and segmental glomerular sclerosis, and diffuse mesangial proliferation. Steroid therapy is applied in all cases of INS. Renal biopsy is usually not indicated before starting corticosteroid therapy. The majority of patients (80-90%) are steroid-responsive. Children with INS who do not achieve a complete remission with corticosteroid therapy commonly present focal and segmental glomerular sclerosis and require treatment with calcineurin inhibitors (cyclosporine or tacrolimus), mycophenolate mofetil or rituximab, plus renin-angiotensin system blockade. In this article we review the recent accepted recommendations for the treatment of children with INS.

Terapia de hepatitis autoinmune no respondedora a esteroides / Autoimmune hepatitis with no response to steroids

Autoimmune hepatitis refractory to corticod therapy is infrequent. Generally, it occurs in severe cases and in young patients. There are several treatment options, including higher doses of the regular medications and, eventually, the use of other immunosuppressive drugs with higher potency, such as mycophenolate, cyclosporin, tacrolimus, among others.

La hepatitis autoinmune refractaria a terapia corticoidal afortunadamente es poco frecuente. Generalmente ocurre en casos de presentación más grave y en pacientes jóvenes. Existen varios esquemas para su enfrentamiento, incluyendo mayores dosis de terapia habitual y, eventualmente, el uso de otros fármacos inmunosupresores de mayor potencia como micofenolato, ciclosporina, tacrolimus y otros.

Síndrome nefrótico corticorresistente: 15 años de experiencia en el Hospital de Pediatría, Centro Médico Nacional Siglo XXI / Steroid-resistant nephrotic syndrome: 15 years experience from the Hospital de Pediatría, Centro Médico Nacional Siglo XXI

Introducción. Desde 1997 se estableció la clínica de síndrome nefrótico en el Hospital de Pediatría del Centro Médico Nacional Siglo XXI. Del 30 al 50% de los niños con síndrome nefrótico corticorresistente evolucionan a insuficiencia renal crónica, y 60-85% remiten con ciclosporina. El objetivo de este estudio fue reportar la respuesta al tratamiento y el pronóstico con este esquema en un grupo de pacientes con síndrome nefrótico corticorresistente. Métodos. Se realizó un estudio retrospectivo, longitudinal en niños con síndrome nefrótico corticorresistente. Se determinaron los resultados de la remisión y la supervivencia renal. Resultados. Se incluyeron 156 pacientes. El 66.7% de sexo masculino, la edad media al diagnóstico fue de 5.9 ± 4.2 años. La biopsia inicial resultó con cambios mínimos en 33 pacientes (21.9%), proliferación mesangial difusa en 74 (49%) y glomeruloesclerosis focal y segmentaria en 44 (29.1%). El promedio de seguimiento fue de 59.3 meses (mín 3 y máx 178 meses). Recibieron ciclosporina 59%; ciclofosfamida, 17.3% y 26 pacientes recibieron secuencialmente ambos esquemas. Remitieron 78.2% de ellos, requirieron diálisis 5.8% y fallecieron 1.9%. La supervivencia renal a 5 años fue de 92.9% y a 10 años, de 80%. La remisión en cambios mínimos y proliferación mesangial difusa fue de 79.8% y 86.5%, respectivamente y en glomeruloesclerosis focal y segmentaria 59.1%. La insuficiencia renal fue más frecuente en glomeruloesclerosis focal y segmentaria (20.4%). El riesgo de desarrollar insuficiencia renal con glomeruloesclerosis focal comparado con proliferación mesangial difusa fue 4.7 veces mayor, y comparado con cambios mínimos, el riesgo fue 8.72 veces mayor. Conclusiones. En este estudio se encontró remisión similar y frecuencia de progresión a insuficiencia renal mejor a lo que se ha reportado en la literatura.

Background. In 1997, the Clinic for Nephrotic Syndrome was established at the Hospital de Pediatría, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social (Mexico City); 30-50% of children with steroid-resistant nephrotic syndrome develop chronic renal failure and 60-80% achieve remission with cyclosporine. The objective of the study was to report treatment response and prognosis using the described scheme in a group of patients with steroid-resistant nephrotic syndrome. Methods. Retrospective study in children with steroid-resistant nephrotic syndrome was done. Remission frequency and renal survival were measured. Results. One-hundred fifty seven patients were studied; 66.7% were male. Mean age at diagnosis was 5.9 ± 4.2 years. Biopsies showed 33 results (21.9%) with minimal changes (MC), 74 (49%) with diffuse mesangial proliferation (DMP) and 44 (29.1%) with focal segmental glomerulosclerosis (FSGS). Mean follow-up time was 59.3 months (minimum 3 months, maximum 178 months); 59% were on cyclosporine and 17.3% cyclophosphamide. Twenty six patients received both treatments and six patients received all three medications; 78.2% entered remission, 5.8% were on dialysis and 1.9% died. Five-year renal survival was 92.9% and 10-year survival was 80%. Remission in patients with MC and DMP was 79.8% and 86.5%, respectively and in FSGS was 59.1%. Chronic renal failure was found more often in FSGS (20.4%). Risk of developing renal failure with FSGS compared with DMP was 4.7 times and FSGS compared with MC risk was 8.7 times greater. Conclusions. Similar rates of remission and better renal survival were found compared with the literature.

Terapia con micofelonato de mofetilo en niños con síndrome nefrótico idiopático córtico resistente

INTRODUCCIÓN: La mayoría de los niños con síndrome nefrótico (SN) responde a tratamiento corticoesteroideo, aunque 15% de los casos son cortico resistentes (CR), y esto constituye un reto clínico. OBJETIVO: Evaluar la respuesta del SNCR al tratamiento inmunosupresor con Micofenolato de Mofetilo (MMF) METODOS: Trabajo prospectivo, incluye 42 pacientes, edades de 3.2 +/- 4.4 años. Tratamiento previo: 8-12 semanas con prednisona, demostrándose córtico-resistencia. Se administró MMF 600 mgs/m²/día/ 6-18 meses y prednisona 1-2 mg/kg, con reducción progresiva en esquema piramidal. Se realizó control clínico periódico y cuantificación de proteinuria, creatinina, proteínas totales y fraccionadas, colesterol y triglicéridos, cada 1-3 meses. Se practicó biopsia renal percutánea en 37 pacientes previamente a iniciar MMF. RESULTADOS: 27 casos (64%) tuvieron remisión completa, 9 remisión parcial y 6 no respondieron. Promedio de seguimiento: 9.2 ± 4.8 meses. 26 pacientes que completaron 18 meses de tratamiento mostraron, después de seguimiento adicional de 4.2 meses, que 18 (69%) mantenían su remisión y 8 (31%) presentaron recaída completa o parcial. Los casos que remitieron totalmente, presentaron lesiones glomerulares mínimas ó lesiones mesangiales en 22 casos (85%); 67% de los 9 casos con remisión parcial mostró lesiones mesangiales y los 6 casos que no respondieron a la terapia mostraron lesiones complejas: 4 glomeruloesclerosis focal y segmentaria, 1 nefropatía membranosa y 1glomerulonefritis mesangioproliferativa. CONCLUSIONES: este trabajo muestra que el MMF es una buena alternativa para el tratamiento de niños con SNCR lográndose remisión completa o parcial en 86% de los casos, con mantenimiento de la remisión en el 70% de los pacientes.

INTRODUCTION: The majority of children with idiopathic nephrotic syndrome respond to steroid therapy; however, approximately 15% of cases are steroid resistant, and this is a clinical challenge. OBJECTIVE: To evaluate the response to Mophetyl Mycophenolate (MMF) in children with steroid resistant nephrotic syndrome (SRNS). METHODS: We recruited 42 children with SRNS, ages 3.2 +/- 4.4 years. All patients received at least one course of 8-12 weeks of prednisone with no response; renal biopsy was performed in 37/42 cases. Dose of MMF was 600 mgs/m²/ day for 6-18 months and prednisone was reduced stepwise. Patients were evaluated clinically periodically, and proteinuria, serum creatinine, serum proteins, cholesterol and triglycerides were checked every 1-3 months. RESULTS: 27(64%) patients had complete remission, 9(22%) partial remission and 6(14%) no response. Mean follow up was 9.2 +/4.8 months. Of the responders 85% had either minimal change disease or mesangial nephritis (MGN) (22 cases); all but one of the partially responders had MGN and those with no response corresponded to 4 cases with focal and segmental glomerulosclerosis (FGS), 1 membranous nephropathy and 1 MGN. Evaluation of 26 patients who completed 18 months treatment showed, after an additional 4. 2 months period of follow up, that 18(69%) maintained their remission and 8 relapsed (31%). CONCLUSIONS: This report shows that MMF is a good therapeutic alternative for SRNS, achieving either a complete or partial remission in the majority of cases (86%) and stabilization of the remission in almost 70% of them.

Asma difícil / Difficult asthma

O autor focaliza a ''asma de difícil controle'', também chamada de ''asma resistente ao tratamento''. Alguns autores incluem a denominação ''asma-corticóide resistente'', mas essa é uma denominação rara e especifíca para uma condição que tem pouco em comum com a ''asma de difícil controle''. Comenta sobre as dificuldades envolvidas na definição dessa forma de asma, o que engloba a perspectiva do médico assistente e sua experiência manejando a asma. Aborda fatores apontados como obstáculos para o controle adequado dos sintomas, ressaltando a adesão ao tratamento. Propõe uma abordagem sistemática para os doentes com uma asma categorizada como de ''difícil controle''. Finaliza por comentar algumas estratégias e medicamentos usados nessa situação particular.

The author focuses on ''difficult to control asthma'', sometimes also called therapy-resistant asthma. Some include in this title ''steroid-resistant asthma'', but this is a very rare and specific condition with little in common with other cases of ''difficult to treat asthma''. He comments on the difficulties involved in its definition, which includes the physician's point of view and experience managing asthma. He points out some associated factors that contribute to the difficulty in controling severe asthma, highlightin problems associated with compliance. He proposes a systematic approach to those with ''difficult to control asthma''. Finally, he comments on some strategies and therapeutic schemes that can be used in this situation.