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Erythrocyte enzymes decomposing reactive oxygen species and gestational age
J K Candlish1, L L Tho, H W Lee
1Biochemistry Department, National University of Singapore, Kent Ridge.
Insights
Antioxidant enzyme activity in newborns changes with gestational age. Superoxide dismutase (SOD) and catalase (CAT) increase, while glutathione peroxidase (GSH-Px) decreases, with lower SOD seen in bronchopulmonary dysplasia.
Area of Science:
- Biochemistry
- Neonatal Physiology
- Pediatric Medicine
Background:
- Antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px), play crucial roles in cellular defense against oxidative stress.
- Understanding the developmental trajectory of these enzymes in neonates is essential for assessing their capacity to manage oxidative challenges, particularly during the transition to extrauterine life.
Purpose of the Study:
- To investigate the activity levels of SOD, CAT, and GSH-Px in neonatal erythrocytes across a spectrum of gestational ages.
- To determine if enzyme activity differs in neonates with respiratory distress syndrome (RDS) or bronchopulmonary dysplasia (BPD) compared to healthy controls.
Main Methods:
- Erythrocytes were collected from neonates with varying gestational ages.
- Enzyme assays were performed to quantify the activity of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px).
- Enzyme activities were compared between neonates with and without respiratory morbidities (RDS, BPD) and matched controls.
Main Results:
- Erythrocyte SOD and CAT activities showed a positive correlation with increasing gestational age.
- Erythrocyte GSH-Px activity exhibited a negative correlation with increasing gestational age.
- No significant difference in enzyme activities was observed between neonates with RDS and gestational age-matched controls.
- Neonates diagnosed with bronchopulmonary dysplasia (BPD) presented with significantly lower SOD activity compared to controls.
Conclusions:
- Neonatal erythrocyte antioxidant enzyme activity is significantly influenced by gestational age, with SOD and CAT increasing and GSH-Px decreasing as gestation progresses.
- While RDS does not appear to directly impact these specific enzyme levels, lower SOD activity in BPD suggests a potential role for oxidative stress and SOD deficiency in the pathogenesis of this condition.
- These findings underscore the critical role of superoxide dismutase in neonatal adaptation to extrauterine life and highlight its potential involvement in the development of chronic lung disease.
Abstract:
Superoxide dismutase (SOD; EC 1.15.1.1), catalase (CAT; EC 1.11.1.6) and glutathione peroxidase (GSH-Px; EC 1.19.1.1) were assayed in erythrocytes from neonates over a range of gestational ages. Both SOD and CAT activities were found to increase, but GSH-Px to decline, with gestational age. Enzyme activities in the erythrocytes of 13 babies who had respiratory distress syndrome (RDS) were not significantly different from controls matched for gestational age, but four with bronchopulmonary dysplasia (BPD) were found to have lower SOD activity. The importance of SOD in the preparation for extrauterine life is substantiated.