Melinda Matyas

By Melinda Mátyás and Gabriela Zaharie

The oxidative stress at newborns is augmented by different conditions like preterm birth, asphyxia, respiratory distress, and intraventricular hemorrhage. Preterm neonates associate a more pronounced oxidative stress than healthy term newborns. Several neonatal conditions like respiratory distress (RDS), asphyxia, intraventricular hemorrhage, bronchopulmonary dysplasia, retinopathy, and necrotizing enterocolitis will increase the oxidative stress. The harmful effects of free radicals are linked to their capacity to react with polyunsaturated fatty acids of cell membranes, proteins, and nucleic acids. Free radicals will produce protein alteration with function loss and lipid peroxidation.

Part of the book: Novel Prospects in Oxidative and Nitrosative Stress

By Melinda Matyas and Gabriela Zaharie

Humans possess defense mechanisms against free radicals: enzymatic and non-enzymatic antioxidants. Antioxidant defense is deficient in newborns and can be enhanced by the action of reactive oxygen species, generated by perinatal diseases such as respiratory distress or asphyxia. Prematurity itself will be associated with deficient antioxidant mechanisms, which are primarily enzymatic, but also non-enzymatic. Under oxidative stress conditions, antioxidant defense is overcome and thus, low-molecular weight free iron is released, which is not bound to transferrin and will play a role in Fenton’s reaction, catalyzing lipid peroxidation. The generated ROS will in turn influence antioxidant defense mechanisms, stimulating their synthesis, as an adaptation mechanism of the body in response to the presence of increased ROS levels.

Part of the book: Antioxidants

By Melinda Matyas

Half of all preterm births are caused or triggered by an inflammation at fetal-maternal interface. The sustained inflammation that preterm neonates are exposed is generated by maternal chorioamnionitis, premature rupture of membranes. This inflammation will facilitate the preterm labor, but also plays an important role in development of disease like: bronchopulmonary dysplasia, necrotizing enterocolitis, retinopathy of prematurity, intraventricular hemorrhage and periventricular leukomalacia. Preterm neonates have immature immune system. The fragile co-regulation between immune defense mechanisms and immunosuppression (tolerance) is often disturbed at this category of patients. They are at high risk of sepsis due to this imbalance between the defense and suppression mechanisms but also several injuries can contribute to the onset or perpetuation of sustained inflammation. They experience altered antigen exposure in contact with hospital-specific germs, artificial devices, drugs, nutritional antigens, and hypoxia or hyperoxia. This is more significant at extremely preterm infants less than 28 weeks of gestation as they have not developed adaptation processes to tolerate maternal and self-antigens.

Part of the book: Current Topics in Caesarean Section