RESUMO Introdução: Tem sido sugerido que os níveis de cistatina C são modificados pela obesidade e inflamação. Além disso, a cistatina C tem sido associada a eventos cardiovasculares e desfechos de mortalidade. Objetivo: Estudar a associação da cistatina C com o perfil metabólico e doença cardiovascular de pacientes em diálise peritoneal. Métodos: Os dados coletados incluíram avaliação clínica, laboratorial e de bioimpedância múltipla de 52 pacientes estáveis em diálise peritoneal. A função renal residual mínima foi definida como > 2mL/min/1,73m2. Resultados: A cistatina C sérica não esteve significativamente associada à excreção peritoneal ou urinária. A correlação negativa da cistatina C com a taxa catabólica protéica normalizada (rho -0,33, p = 0,02) e uma tendência de correlação positiva com a gordura corporal relativa (rho 0,27, p = 0,05) não foram independentes da função renal residual. A cistatina C não se associou significativamente à doença cardiovascular (p = 0,28), nem com hemoglobina glicada (p = 0,19) ou proteína C reativa (p = 0,56). No modelo multivariado, idade e diabetes foram os mais fortes preditores de doença cardiovascular (razões de probabilidade 1,09, p = 0,029 e 29,95, p = 0,016, respectivamente) enquanto a gordura corporal relativa se associou negativamente à doença cardiovascular (p = 0,038). A cistatina C não se associou significativamente com doença cardiovascular (p = 0,096), tampouco a função residual mínima (p = 0,756). Conclusão: Neste grupo de pacientes em diálise peritoneal, a cistatina C não se correlacionou com o estado metabólico ou inflamatório, nem com doença cardiovascular, após ajuste para função renal residual.

ABSTRACT Introduction: It has been suggested that cystatin C levels are modified by obesity and inflammation. Furthermore, cystatin C has been associated with cardiovascular events and mortality outcomes. Aim: To study the association of cystatin C with the metabolic profile and cardiovascular disease of peritoneal dialysis patients. Methods: Data collected included clinical, laboratorial, and multifrequency bioimpedance assessment of 52 stable peritoneal dialysis patients. Minimal residual renal function was defined as > 2mL/min/1.73m2. Results: Serum cystatin C was not significantly associated with peritoneal or urinary cystatin C excretion. Negative correlation of cystatin C with normalized protein catabolic rate (rho -0.33, p = 0.02) and a trend towards positive correlation with relative body fat (rho 0.27, p = 0.05) were not independent from residual renal function. Cystatin C was not significantly associated with cardiovascular disease (p = 0.28), nor with glycated hemoglobin (p = 0.19) or c-reactive protein (p = 0.56). In the multivariate model, both age and diabetes were the strongest predictors of cardiovascular disease (odds ratio 1.09, p = 0.029 and odds ratio 29.95, p = 0.016, respectively), while relative body fat was negatively associated with cardiovascular disease (p = 0.038); neither cystatin C (p = 0.096) nor minimal residual renal function (p = 0.756) reached a significant association with cardiovascular disease. Conclusions: In this group of peritoneal dialysis patients, cystatin C did not correlate with the metabolic or inflammatory status, nor cardiovascular disease, after adjustment for residual renal function.

Introdução: O rituximab pode ser uma arma terapêutica útil no tratamento da sindroma nefrótica complicada, permitindo a redução de inibidores da calcineurina e de corticóides. Métodos: Estudo retrospetivo de todas as crianças que receberam rituximab no tratamento de sindroma nefrótica num hospital terciário. Todos os doentes, exceto um (dose única), receberam quatro infusões de rituximab 375mg/m2 com intervalo de uma semana, tendo um seguimento mínimo de quatro meses e máximo de 118 meses. Resultados: Foram incluídos 11 doentes, três com sindroma nefrótica corticorresistente e oito com sindroma nefrótica corticodependente ou multirrecidivante. A relação masculino:feminino foi de 8:3, com idade mediana no quadro inaugural de 2,7 anos (mínimo 1,7 - máximo 9,9). Todos os doentes foram tratados previamente com inibidores da calcineurina, oito com ciclofosfamida e sete com micofenolato de mofetil. Dois doentes não responderam, evoluindo para a doença renal crónica estádio 5. Registou-se uma mediana de três episódios de recidiva nos seis meses pré-rituximab e nenhuma recidiva nos seis meses pós-rituximab (p=0.013). Foi possível reduzir significativamente a dose de corticóides (p=0.001). Dois doentes recidivaram aos 9 e 12 meses pós-rituximab. Um outro doente recidivou imediatamente após transplante renal. Verificou-se recuperação da contagem de células CD19 em seis doentes, incluindo dois recidivantes. Não se reportou nenhum caso de infeção severa ou neoplasia. Conclusão: O rituximab reduziu significativamente o número de recidivas e a dose de corticóides na sindroma nefrótica complicada. A recuperação da contagem de células CD19 não previu a recidiva, mas pode indicar a necessidade de doses adicionais de rituximab.

Background: In children with idiopathic nephrotic syndrome, rituximab can maintain short-term remission allowing steroids and calcineurin inhibitors taper. Methods: We retrospectively reviewed all children receiving rituximab for idiopathic nephrotic syndrome at a tertiary hospital. All patients, except one who received a single dose, had four infusions of 375mg/m2 of rituximab at a one-week interval, minimum follow-up duration of four and maximum 118 months. Results: Eleven patients were included, three patients with steroid resistant nephrotic syndrome and eight steroid dependent or frequently relapsing nephrotic syndrome. Male:female ratio was 8:3 and median age at onset was 2.7 (minimum 1.7-maximum 9.9) years-old. All patients received a trial of calcineurin inhibitors, eight received cyclophosphamide and seven mycophenolate mofetil. Remission of proteinuria was observed in nine patients. Two patients were non-responders evolving to end-stage renal disease. Patients experienced in median three relapses during the six months preceding rituximab. Responders did not relapse in the following six months (p=0.013) and daily dose of prednisolone was significantly reduced (p=0.001). Two patients relapsed at 9 and 12 months after rituximab. Another patient experienced relapse immediately after kidney transplant, successfully treated with our protocol for focal and segmental glomerulosclerosis relapse. Recovery of CD19 cells counting was observed in six patients including two relapsing patients. No severe infection or neoplasia were reported. Conclusions: Rituximab successfully reduced relapsing in complicated idiopathic nephrotic syndrome, steroid dose and enabled other immunosuppressants weaning off in most patients. Recovery of CD19 cells did not anticipate relapse, but may herald the need for additional rituximab infusions.

Introduction: Arteriovenous fistula has been associated with improved morbimortality in hemodialysis patients. This has resulted in the “fistula First, catheter last” initiative. Nonetheless, the survival benefit of arteriovenous fistula has been questioned. Methods: We conducted a retrospective observational study of all patients with non-end stage renal disease referred for first vascular access building between January 2014 and December 2015 in our hospital center. Our main goal was to evaluate the clinical impact and burden of building fistula in predialysis patients. Results: During this period, of 178 first arteriovenous accesses placed, 87 patients remained in predialysis and 91 patients started a chronic hemodialysis program. Median follow-up time by a nephrologist was 3.9 (2.5, 9.7) years. The mean age was 65.8±14.7 years, with 50.6% (n=90) of male patients. A higher rate of thrombosis in the predialysis group (26% vs 13%, p=0.037) was observed, but vascular access survival did not differ significantly (55% vs 67%, p=0.12). Mean vascular access placing was higher in the predialysis group (1.4±0.7 vs 1.2±0.4, p=0.006) and less interventions were requested (0.2±0.5 vs 0.3±0.6, p=0.10). Median time from vascular access placement to hemodialysis start was 22 (13, 41) months. At hemodialysis initiation, 10 (10.9%) patients used a central venous catheter; 80 (87.9%) patients an arteriovenous fistula, and one patient a graft. A total of 227 vascular accesses were built; 121 (53.3%) in predialysis vs 106 (46.7%) in incident hemodialysis patients. In a multivariate model, the presence of a functional arteriovenous fistula at hemodialysis start was only associated with a trend to survival benefit (HR 0.38, 95% CI 0.14-1.00, p=0.05). Conclusions: Our results stress the need for an individual approach and for future tools to assess the risk of death and progression to end-stage renal disease, therefore helping reduce the number of unutilized vascular accesses and rising cost of interventions