Cysteine, cystine or N-acetylcysteine supplementation in parenterally fed neonates

Stefanovic

Invest. Ophthalmol. Vis. Sci.

et al. 2013

PURPOSE. Glutathione peroxidase-1 (GPx1) is highly expressed during normal retinal maturation; however, its role in retinopathy of prematurity (ROP) is not fully understood. We postulated that GPx1 plays an important role in protecting the premature retina from oxidative injury in a mouse model of ROP.METHODS. ROP was induced in wild-type (WT) and GPx1 knockout (KO) mice by exposing neonatal mice to 75% oxygen from postnatal days 7 to 11, followed by 1 week of room air. Structural effects of ROP were evaluated by retinal histology, and gene expression of retinal pro-angiogenic factors was measured by qRT-PCR. RESULTS.Retinas from ROP GPx1 KO mice had a significantly larger central avascular area compared to those from ROP WT mice (P < 0.001), indicative of a more severe vaso-obliteration. In ROP GPx1 KO mice, retinas also displayed increased preretinal neovascularization (P ¼ 0.05) with a concurrent increase in the expression of vascular endothelial growth factor (P < 0.05) compared to values in ROP WT mice. Elevated oxidative stress was observed in ROP GPx1 KO retinas as evidenced by increased nitrotyrosine immunolabeling (P < 0.01) and superoxide (P < 0.05) in vessels compared to ROP WT retinas. In contrast to these findings of exacerbated retinal vascular injury in GPx1 KO mice, Müller cell gliosis and microglial density were similar in ROP GPx1 KO and ROP WT mice.CONCLUSIONS. GPx1, an important antioxidant enzyme of the premature retina, afforded protection against oxidative stress and oxidative injury in ROP. Lack of GPx1 was associated with increased oxidative stress, an increase in retinal avascular area, upregulation of retinal VEGF, and increased neovascularization in a mouse model of ROP. (Invest Ophthalmol Vis Sci. 2013;54:555-562)

Section: Discussionmentioning

confidence: 87%

Lack of the Antioxidant Glutathione Peroxidase-1 (GPx1) Exacerbates Retinopathy of Prematurity in Mice

Stefanovic

Invest. Ophthalmol. Vis. Sci.

et al. 2013

“…The same group (9) and others (10) found that when cysteine was supplemented to cysteine-free PN, there was no improvement in growth and nitrogen balance in the supplemented group with both groups achieving similar to in utero nitrogen retention. However, other reports have concluded that although growth was not affected, nitrogen balance was increased with cysteine supplementation (11). More recent stable isotope data showed significant transfer of label from D-[U- 13 C]glucose into cysteine derived from (apo) B-100 in preterm infants fed cysteine-free PN (12).…”

mentioning

confidence: 95%

The Addition of Cysteine to the Total Sulphur Amino Acid Requirement as Methionine Does Not Increase Erythrocytes Glutathione Synthesis in the Parenterally Fed Human Neonate

et al. 2010

Controversy exists as to whether the parenterally (PN) fed human neonate is capable of synthesizing adequate cysteine from methionine if the total dietary requirement for sulfur amino acid (SAA) is provided as methionine only. The goal of this study was to gather data on whether glutathione (GSH) synthesis is maximized at a methionine intake previously shown to be adequate for protein synthesis in the PN-fed human neonate. We measured GSH concentration, fractional, and absolute synthesis rate in five PN-fed human neonates. Each neonate underwent two isotope infusion studies of 7 h duration after a 2-d adaptation to the total SAA requirement (methionine only) and again after a further 2-d adaptation to the same methionine intake supplemented with cysteine at 10 mg ⅐ kg Ϫ1 ⅐ d Ϫ1 . Cysteine supplementation did not significantly affect GSH synthesis. These data suggest that term infants are capable of synthesizing cysteine from methionine, not only for protein but also for GSH synthesis. (Pediatr Res 67: 320-324, 2010)

“…Muchas unidades norteamericanas suplementan la NP con hierro (en forma de dextrano) 3 , aunque esta opción implique riesgos importantes 32 . A pesar de no haber evidencia científica de las ventajas de la suplementación de NP neonatal con cisteína 33 , glutamina 34 o carnitina 35 , algunas unidades portuguesas optan por esta suplementación.…”

Section: Discussionunclassified

Prácticas de prescripción de nutrición parenteral neonatal en Portugal

Neves

Pereira‐da‐Silva

Fernández-Llimós

2014

Anales de Pediatría

PALABRAS CLAVE Nutrición parenteral neonatal; Prescripción; PortugalResumen Introducción: La utilización de normas de orientación para la nutrición parenteral neonatal mejora la eficiencia y la seguridad de su prescripción. Objetivo: Evaluar la práctica de prescripción de nutrición parenteral neonatal en Portugal y el cumplimiento del Consenso Nacional (2008). Métodos: Encuesta de respuesta múltiple sobre la prescripción de nutrición parenteral (NP) enviada a los coordinadores de las 50 unidades de cuidados especiales neonatales portuguesas, tanto públicas como privadas, siendo 25 de nivel ii y 25 de nivel iii. Resultados: Se prescribe NP en 32 unidades neonatales, habiendo 23 (71,9%) respondido la encuesta. De estas, 19 (82,6%) afirman tener como referencia el Consenso Nacional y las restantes siguen protocolos internos; 17 (73,9%) afirman preferir la prescripción mediante soporte informático. En recién nacidos pretérmino, la mayoría reporta una administración cautelosa de líquidos en la primera semana posnatal; inicio de aminoácidos desde el primer día posnatal con 1,5-3 g/kg/día y aumento hasta 3-4 g/kg/día; inicio de lípidos en los 3 días posnatales con 1 g/kg/día y aumento hasta 3 g/kg/día; administración de 40-70 mg/kg/día de calcio y fósforo, con un ratio calcio:fósforo de 1,7:1 (mg:mg), y estimación de la osmolaridad de las soluciones y control semanal de la trigliceridemia, uremia, fosforemia y función hepática. Conclusiones: Por la elevada tasa de respuesta la muestra probablemente es representativa de la práctica de prescripción de nutrición parenteral neonatal en Portugal. La mayoría de las unidades tienen como referencia el Consenso Nacional, lo que contribuye a unos mejores cuidados de los recién nacidos.