Correction of hypozincemia following liver transplantation in children is associated with reduced urinary zinc loss

Abstract

Zinc deficiency is a relatively common problem in children with chronic liver disease. We have previously shown inappropriate urinary zinc excretion in children with chronic liver disease and hypozincemia. This study was designed to determine if zinc deficiency and inappropriate urinary zinc losses are corrected in children with liver disease by liver transplantation. Thirty-three patients (age 1-19 years) underwent 35 liver transplants for acute and chronic liver disease. At the time of transplant, 17 patients had low plasma zinc (hypozincemic) (plasma zinc, 45.4 ؎ 1.8 g/dL), whereas 18 had normal plasma zinc (75.7 ؎ 3.8). Before transplant, patients with zinc deficiency had higher urinary zinc to creatinine ratio compared with those with normal zinc status (6.6 ؎ 1.9 vs. 2.2 ؎ 0.6; P ‫؍‬ .03) and lower serum albumin concentrations (low: 2.8 ؎ 0.1 vs. normal: 3.3 ؎ 0.2; P ‫؍‬ .02). After transplant, there was a significant reduction in urinary zinc losses in the hypozincemic group followed by normalization of plasma zinc levels by 7 days posttransplant. These data suggest that the abnormal renal zinc homeostasis that is present in approximately 50% of pediatric patients undergoing liver transplant is rapidly improved and biochemical zinc deficiency is reversed after liver transplantation. (HEPATOLOGY 1999;29:830-833.)

Baixas concentrações plasmáticas de zinco em pacientes pediátricos com cirrose

“…28 A positive association between supplementation and the increase in growth velocity in children was also observed by Nakamura et al 29 and by Michaelsen et al 30 Our study did not find any association between anthropometric data and plasma zinc concentrations, which is in agreement with other studies of pediatric patients with cirrhosis. 19,24 In a recent study that evaluated plasma zinc concentration in pediatric patients with cystic fibrosis, the body mass index was not correlated with low plasma zinc concentrations as well. 25 Trials of zinc supplementation have shown positive effects on clinical outcomes and growth, especially among children who are stunted.…”

“…21 Hambidge et al, 22 A significant correlation between zinc and albumin was found in our study and by other authors who studied patients with liver disease and also cystic fibrosis. 24,25 It is interesting to notice that even in patients with low albumin concentrations the supplementation may correct hypozincemia. 26,27 Low plasma zinc in patients with liver cirrhosis does not seem to be associated with the diet.…”

Low plasma zinc concentrations in pediatric patients with cirrhosis

“…Uma correlação significativa entre zinco e albumina foi encontrada em nosso estudo e por outros autores que estudaram pacientes com doença hepática e fibrose cística 24,25 . É interessante notar que, mesmo em pacientes com baixas concentrações de albumina, a suplementação pode corrigir a hipozincemia 26,27 .…”

“…Uma associação positiva entre a suplementação e o aumento da velocidade do crescimento em crianças também foi observada por Nakamura et al 29 e por Michaelsen et al 30 . Nosso estudo não encontrou qualquer associação entre os dados antropométricos e as concentrações plasmáticas de zinco, o que está de acordo com outros estudos envolvendo pacientes pediátricos com cirrose 19,24 . Em um estudo recente que avaliou a concentração plasmática de zinco em pacientes pediátricos com fibrose cística, o índice de massa corporal também não foi correlacionado com baixas concentrações de zinco plasmático 25 .…”

Deficiência de zinco em crianças e adolescentes com doenças hepáticas crônicas

“…Uma pesquisa genética que teve como objetivo identificar e mapear os genes relacionados ao Zn humano mostrou que um desses genes foi localizado em região deficiente na Síndrome de Alagille, o que indica a importância da avaliação da deficiência de Zn nesse grupo de pacientes (49) . Narkewicz et al (50) mostraram que 48% das crianças hepatopatas crônicas estudadas e que aguardam por transplante hepático apresentavam deficiência de Zn plasmático. Dentre essas crianças, a excreção urinária do mineral mostrou-se alta e a concentração de albumina, proteína ligante ao Zn plasmático, foi baixa.…”