Papers by Jeanclaude Lavoie
Free Radical Biology and Medicine, 2014
Introduction: Hypoalveolarization is a main characteristic of bronchopulmonary dysplasia (BPD) th... more Introduction: Hypoalveolarization is a main characteristic of bronchopulmonary dysplasia (BPD) that affects 50% of infants born < 28 weeks of gestation. Animal studies report that ascorbylperoxide (AscOOH) generated in parenteral nutrition (PN) devoid of light protection induces oxidized redox potential and loss of alveoli following an exaggerated apoptosis. Because AscOOH is a substrate of glutathione peroxidase, we hypothesized that improving of the in vivo glutathione level can limit BPD development. The aim was to assess in newborn animals that addition of glutathione in PN prevents the deleterious effects of AscOOH. Methods: Guinea pigs (n = 40) aged of 3 days were divided in 6 groups to receive the following intravenous solutions through a catheter in jugular vein. Sham: animals fed regular chow, catheter was closed; PN
Free Radical Biology and Medicine, 2015
Bronchopulmonary dysplasia, a main complication of prematurity, is characterized by an alveolar h... more 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. the addition of glutathione (GSSG) in parenteral nutrition improves detoxification of ascorbylperoxide by glutathione peroxidase and therefore prevents exaggerated apoptosis and loss of alveoli. 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) 180μM ascorbylperoxide; 5) PN(+L)+10μM GSSG; 6) ascorbylperoxyde+10μM GSSG. After 4 days, lungs were sampled and prepared for histology and biochemical determinations. Data were analysed by ANOVA, p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.05. The Km of ascorbylperoxide for glutathione peroxidase was 126±6μM and Vmax was 38.4±2.5nmol/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. 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.
Free Radical Biology and Medicine, 2015
JPEN. Journal of parenteral and enteral nutrition, Aug 1, 2016
Ascorbylperoxide (AscOOH) is a hydrogen peroxide-dependent by-product of ascorbic acid that conta... more Ascorbylperoxide (AscOOH) is a hydrogen peroxide-dependent by-product of ascorbic acid that contaminates parenteral nutrition. In a guinea pig model, it caused oxidized redox potential, increased apoptosis, and decreased alveolarization. AscOOH detoxification is carried out by glutathione peroxidase (GPX). We hypothesize that extremely preterm infants have limited capacity for AscOOH detoxification. Our objective was to determine if there is an association between an early level of urinary AscOOH and later development of bronchopulmonary dysplasia (BPD) or death. This prospective cohort study included 51 infants at <29 weeks of gestation. Baseline clinical characteristics and clinical outcomes data were collected. Urine samples were collected on days 3, 5, and 7 of life for urinary AscOOH. Blood samples on day 7 were collected for total plasma glutathione, GPX, and glutathione reductase. Chi-square, Student'sttest, Spearman correlation (r), linear regression (adjustedr(2)), a...
Redox biology, Aug 17, 2015
The oxidation of the methionine adenosyltransferase (MAT) by the combined impact of peroxides con... more The oxidation of the methionine adenosyltransferase (MAT) by the combined impact of peroxides contaminating parenteral nutrition (PN) and oxidized redox potential of glutathione is suspected to explain its inhibition observed in animals. A modification of MAT activity is suspected to be at origin of the PN-associated liver disease as observed in newborns. We hypothesized that the correction of redox potential of glutathione by adding glutathione in PN protects the MAT activity. To investigate whether the addition of glutathione to PN can reverse the inhibition of MAT observed in animal on PN. Three days old guinea pigs received through a jugular vein catheter 2 series of solutions. First with methionine supplement, (1) Sham (no infusion); (2) PN: amino acids, dextrose, lipids and vitamins; (3) PN-GSSG: PN+10μM GSSG. Second without methionine, (4) D: dextrose; (5) D+180μM ascorbylperoxide; (6) D+350μM H2O2. Four days later, liver was sampled for determination of redox potential of gl...
Archives of Disease in Childhood, 2014
The Journal of nutrition, 2002
We showed recently that iron + ascorbate can impair the assembly of intestinal lipoproteins. Howe... more We showed recently that iron + ascorbate can impair the assembly of intestinal lipoproteins. However, we could not determine whether these changes were caused by iron + ascorbate-mediated lipid peroxidation per se. We therefore conducted studies to evaluate how antioxidants antagonize the iron + ascorbate-induced derangements. To this end, Caco-2 cells, a reliable experimental intestinal model, were incubated with iron + ascorbate (0.2 mmol/L each) alone or with different concentrations of catalase, mannitol, tocopherol or BHT. Exposing Caco-2 cells to iron + ascorbate increased malondialdehyde levels fourfold (P < 0.0001); this effect was decreased markedly (P < 0.02) in the presence of BHT. Furthermore, BHT normalized the abnormal intracellular events involved in fat absorption, i.e., lipid esterification, cholesterol synthesis and apolipoprotein production. On the other hand, it did not fully restore the secretion of lipids and lipoproteins. Thus, our current data imply tha...
Redox biology, 2014
Bronchopulmonary dysplasia is one of the main complications associated with extreme prematurity. ... more Bronchopulmonary dysplasia is one of the main complications associated with extreme prematurity. Oxidative stress is suspected to be a trigger event of this lung disease, which is characterized by impaired alveolar development. Peroxides, mainly ascorbylperoxide and H2O2, are known contaminant of parenteral nutrition. We hypothesize that these oxidant molecules induce bronchopulmonary dysplasia development. The aim was to determine if the infusion of ascorbylperoxide, whether in presence or absence of H2O2, is associated with oxidative stress, apoptosis and loss of alveoli in the lungs of newborn guinea pigs. Three-day-old guinea pigs received parenteral solutions containing 0, 20, 60 or 180 µM ascorbylperoxide in the presence or not of 350 µM H2O2 (concentrations similar to those measured in parenteral nutrition). After 4 days, the lungs were collected for determination of glutathione's redox potential, caspase-3 activation (an apoptosis marker), alveolarization index (by histo...
Seminars in Perinatology, 2006
Pediatric Pulmonology, 2005
Pediatric Critical Care Medicine, 2010
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Papers by Jeanclaude Lavoie