Effects of parenteral cysteine and glutathione feeding in a baboon model of severe prematurity

Background: The availability of cysteine for glutathione synthesis is low i n premature infants with respiratory distress. Objective: The effects of gestational age, oxygen delivery, and cysteine in fusion or glutathione infusion, or both, on plasma total cysteine and other methionine metabolites were studied in a baboon model of severe premature birth with respiratory distress. Design: Premature baboons were studied as part of the multi-investigator Na tional Institutes of Health Collaborative Project on Bronchopulmonary Dyspl asia. Premature baboons, 125 d (69% of term) or 140 d (78% of term) of gest ational age, were maintained in neonatal intensive care units for less than or equal to 14 d. Parenteral feeding with or without supplemental cysteine and glutathione infusions was given. Plasma total cysteine, methionine, N- methylglycine, cystathionine, and the other methionine metabolites were mon itored by capillary gas chromatography-mass spectrometry. Results: Cord blood plasma total cysteine was the lowest in the 125-d-old p remature baboons. Plasma total cysteine decreased in the first 3 d after de livery in the 125-d-old (but not in the 140-d-old) premature baboons even w hen cysteine was infused. Supplementation with glutathione from the first d ay of life raised plasma total cysteine markedly. Plasma cystathionine incr eased in all animals after birth but increased 4-fold in 125-d-old animals with glutathione infusion. At 6 and 10 d postdelivery, the arterial-alveola r oxygen gradient was significantly higher in the 125-d-old animals that re ceived glutathione infusions. Conclusions: Glutathione, but not supplemental cysteine, infusions prevente d the postdelivery decline in plasma cysteine concentrations in premature b aboons. Glutathione infusions resulted in marked elevations of plasma cysta thionine concentration.