Wesam Elremaly1, Ibrahim Mohamed2, Thérèse Rouleau3, Jean-Claude Lavoie4. 1. Department of Nutrition, CHU Sainte-Justine, University of Montréal, Montréal, Qc, Canada H3T 1C5. 2. Department of Pediatrics, CHU Sainte-Justine, University of Montréal, Montréal, Qc, Canada H3T 1C5. 3. Department of Nutrition, CHU Sainte-Justine, University of Montréal, Montréal, Qc, Canada H3T 1C5; Department of Pediatrics, CHU Sainte-Justine, University of Montréal, Montréal, Qc, Canada H3T 1C5. 4. Department of Nutrition, CHU Sainte-Justine, University of Montréal, Montréal, Qc, Canada H3T 1C5; Department of Pediatrics, CHU Sainte-Justine, University of Montréal, Montréal, Qc, Canada H3T 1C5. Electronic address: jean-claude.lavoie@umontreal.ca.
Abstract
UNLABELLED: Bronchopulmonary dysplasia, a main complication of prematurity, is characterized by an alveolar hypoplasia. Oxidative stress is suspected to be a trigger event in this population who has a low level of glutathione, a main endogenous antioxidant, and who receives high oxidative load, particularly ascorbylperoxide from their parenteral nutrition. HYPOTHESIS: the addition of glutathione (GSSG) in parenteral nutrition improves detoxification of ascorbylperoxide by glutathione peroxidase and therefore prevents exaggerated apoptosis and loss of alveoli. METHODS: Ascorbylperoxide is assessed as substrate for glutathione peroxidase in Michaelis-Menten kinetics. Three-days old guinea pig pups were divided in 6 groups to receive, through a catheter in jugular vein, the following solutions: 1) Sham (no infusion); 2) PN(-L): parenteral nutrition protected against light (low ascorbylperoxide); 3) PN(+L): PN without photo-protection (high ascorbylperoxide); 4) 180 μM ascorbylperoxide; 5) PN(+L)+10 μM GSSG; 6) ascorbylperoxyde+10 μM GSSG. After 4 days, lungs were sampled and prepared for histology and biochemical determinations. Data were analysed by ANOVA, p < 0.05 RESULTS: The Km of ascorbylperoxide for glutathione peroxidase was 126 ± 6 μM and Vmax was 38.4 ± 2.5 nmol/min/ U. The presence of GSSG in intravenous solution has prevented the high GSSG, oxidized redox potential of glutathione, activation of caspase-3 (apoptosis marker) and loss of alveoli induced by PN(+L) or ascorbylperoxide. CONCLUSION: A correction of the low glutathione levels observed in newborn animal on parenteral nutrition, protects lungs from toxic effect of ascorbylperoxide. Premature infants having a low level of glutathione, this finding is of high importance because it provides hope in a possible prevention of bronchopulmonary dysplasia.
UNLABELLED: Bronchopulmonary dysplasia, a main complication of prematurity, is characterized by an alveolar hypoplasia. Oxidative stress is suspected to be a trigger event in this population who has a low level of glutathione, a main endogenous antioxidant, and who receives high oxidative load, particularly ascorbylperoxide from their parenteral nutrition. HYPOTHESIS: the addition of glutathione (GSSG) in parenteral nutrition improves detoxification of ascorbylperoxide by glutathione peroxidase and therefore prevents exaggerated apoptosis and loss of alveoli. METHODS:Ascorbylperoxide is assessed as substrate for glutathione peroxidase in Michaelis-Menten kinetics. Three-days old guinea pig pups were divided in 6 groups to receive, through a catheter in jugular vein, the following solutions: 1) Sham (no infusion); 2) PN(-L): parenteral nutrition protected against light (low ascorbylperoxide); 3) PN(+L): PN without photo-protection (high ascorbylperoxide); 4) 180 μM ascorbylperoxide; 5) PN(+L)+10 μM GSSG; 6) ascorbylperoxyde+10 μM GSSG. After 4 days, lungs were sampled and prepared for histology and biochemical determinations. Data were analysed by ANOVA, p < 0.05 RESULTS: The Km of ascorbylperoxide for glutathione peroxidase was 126 ± 6 μM and Vmax was 38.4 ± 2.5 nmol/min/ U. The presence of GSSG in intravenous solution has prevented the high GSSG, oxidized redox potential of glutathione, activation of caspase-3 (apoptosis marker) and loss of alveoli induced by PN(+L) or ascorbylperoxide. CONCLUSION: A correction of the low glutathione levels observed in newborn animal on parenteral nutrition, protects lungs from toxic effect of ascorbylperoxide. Premature infants having a low level of glutathione, this finding is of high importance because it provides hope in a possible prevention of bronchopulmonary dysplasia.