Changes in anti-oxidant enzymes and lipid peroxidation in hyaline membrane disease

Effects of mode of delivery on pro-oxidant/antioxidant balance in fetal circulation

Objective: This study was undertaken to assess the influence of mode of delivery on the balance between pro-oxidant/antioxidant systems in fetal circulation. Materials and methods: Both umbilical arterial and venous blood samples were obtained from 37 pregnant women who delivered by spontaneous vaginal delivery (VD group) and from 29 pregnant women who delivered by elective cesarean section (CS group). Oxidative stress and antioxidant activity were evaluated by reactive oxygen metabolites (d-ROMs) and biological antioxidant potential (BAP), respectively. Results: The d-ROMs values of the VD group were higher than that of the CS group in both umbilical arterial and venous blood and these differences were found to be statistically significant (p < .01 and p < .01, respectively). The BAP values of only the umbilical arterial blood were found to be statistically significant (p < .01), with values from the VD group being higher than those of the CS group. In all measurements, the d-ROMs values averaged below 120 CARR U and BAP values averaged above 2200 µmol/L. The ratio of BAP/d-ROMs difference was found to be statistically significant (p < .01) only in the umbilical venous blood, with ratios in the VD group being lower than those in the CS group. Conclusions: Our statistical analyses suggest that vaginal delivery has an effect on increasing oxidative stress as a result of the stress of labor and that an elective cesarean section does not impair the mother's oxidative stress status. Furthermore, the high BAP values in all the measurements suggest that neonates just after birth have the ability to cope with oxidative stress. Rationale   In many studies, the diversity of views on the influence of mode of delivery on the redox status of neonates is likely to be caused by the use of different biomarkers to measure either the oxidative stress, the antioxidant activity, or both. Furthermore, incomplete explanation for sampling cord blood in these studies, either arterial, venous blood or both, complicates matters. To solve the above, this study was designed to assess the effects of mode of delivery on both pro-oxidants, via d-ROMs, and antioxidants, via BAP, in both umbilical arterial and venous blood samples obtained just after birth. There are no existing studies of BAP in both umbilical arterial and venous blood to which we can refer. In conclusion, our study suggests that the pro-oxidant/antioxidant balance in neonates just after birth is better than may be expected when compared to the potentials of adults (including pregnant mothers) according to interpretations of BAP/d-ROMs. This can be understood that neonates may have already been endowed with the ability to cope with oxidative stress, as informed by high BAP values in both umbilical arterial and venous blood. Vaginal delivery may have an effect on increasing oxidative stress as a result of the stress of labors (as measured by d-ROMs), and an elective cesarean section, which has better BAP/d-ROMs in umbilical venous blood than that of vaginal delivery, may not impair the mother's oxidative stress status.

A novel approach to study oxidative stress in neonatal respiratory distress syndrome

Background

Respiratory distress syndrome of the neonate (neonatal RDS) is still an important problem in treatment of preterm infants. It is accompanied by inflammatory processes with free radical generation and oxidative stress. The aim of study was to determine the role of oxidative stress in the development of neonatal RDS.

Methods

Markers of oxidative stress and antioxidant activity in umbilical cord blood were studied in infants with neonatal respiratory distress syndrome with reference to healthy newborns.

Results

Status of markers of oxidative stress (malondialdehyde, protein carbonyl and 8-hydroxy-2-deoxy guanosine) showed a significant increase with depleted levels of total antioxidant capacity in neonatal RDS when compared to healthy newborns.

Conclusion

The study provides convincing evidence of oxidative damage and diminished antioxidant defenses in newborns with RDS. Neonatal RDS is characterized by damage of lipid, protein and DNA, which indicates the augmentation of oxidative stress.

General significance

The identification of the potential biomarker of oxidative stress consists of a promising strategy to study the pathophysiology of neonatal RDS.

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Oxidative stress is important in the pathogenesis of neonatal respiratory distress syndrome (RDS).

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Oxidative stress biomarkers were studied in neonates with RDS.

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The high concentration of products of lipid peroxidation, protein damage and oxidative DNA damage were found.

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High oxidative stress was correlated with presence of RDS in newborns.

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Our results are an important step in continuous monitoring of the neonatal RDS.

Effects of sevoflurane and desflurane on oxidative stress during general anesthesia for elective cesarean section

BACKGROUND

Anesthetic agents might considerably influence maternal-fetal oxidative stress and antioxidants during cesarean section (CS). The aim of this study was to investigate the effects of desflurane and sevoflurane on oxidative stress parameters both in mothers and newborns undergoing elective CS.

MATERIALS AND METHODS

Eighty ASA physical status I-II, term parturients undergoing elective CS under general anesthesia were randomized to desflurane (Group D) and sevoflurane (Group S) groups. Blood samples were collected from mothers before operation and postoperatively and umbilical artery samples were obtained at delivery. Total oxidant status (TOS), total antioxidant capacity (TAC) status, lipid hydroperoxide (LOOH), and free sulfhydryl (-SH) levels were measured and oxidative stress index was calculated. Secondary outcomes included maternal hemodynamics.

RESULTS

Preoperative LOOH, TOS, OSI, TAC, and -SH levels were similar among groups. Postoperative maternal serum LOOH, TOS, and OSI levels were significantly increased in Group D compared to Group S (p = 0.003, p = 0.005, p = 0.04; respectively). Postoperative umbilical artery LOOH, TOS, OSI levels were also significantly increased in Group D compared to Group S (p = 0.04, p = 0.02, p = 0.01; respectively). Postoperative TOS (p = 0.001, < 0.001 respectively) and OSI (p = 0.003, < 0.001 respectively) levels in both Group D and Group S were statistically significantly decreased compared to preoperative levels. Postoperative LOOH and -SH levels in Group S (p = 0.04, 0.029 respectively) were statistically significantly decreased compared to preoperative levels. There were no significant differences in TAC and -SH levels among groups (p = nonsignificant [n.s.]). Maternal perioperative mean blood pressure and heart rate were similar among groups (p = n.s.).

CONCLUSION

Oxidative stress indices might be modified with preferred anesthetic agent and sevoflurane showed more favorable effects than desflurane in view of oxidative stress.

On the relation of oxidative stress in delivery mode in pregnant women; a toxicological concern

The objective was to investigate the effect two modes of labor (vaginal delivery and elective cesarean section) on thiobarbituric reactive substances (TBARS) as markers of lipid peroxidation, total antioxidant power (ferric reducing ability, TAP), and total thiol molecules (TTM) in blood of mothers and their newborns. One hundred and twenty women with normal pregnancy and normal blood biochemical parameters were divided into groups of vaginal delivery (VD) and elective cesarean surgery (ECS). Blood samples were obtained firstly in the time 37-40 weeks of pregnancy and secondly during labor phase for VD or during ECS. Blood samples from umbilical cord arterial of newborns were also obtained at birth after separation of cord. Plasma levels of TBARS, TAP, and TTM were determined. There was no significant differences between VD and ECS mothers before labor in plasma levels of TBARS, TTM, and TAP. Mothers in the VD group showed a significant increase in TBARS (p < 0.05) after delivery. And TTM level showed a significant increase in ECS group (p < 0.05) as compared to pre-delivery levels. Comparing oxidative stress variables between VD and ECS groups after labor, plasma levels of TBARS, and TTM significantly increased (p < 0.05) in VD mothers. TAP was not significantly different between VD and ECS groups. Newborn of VD mothers showed a significant increase in TBARS (p < 0.05), and TAP (p < 0.05) as compared to newborn of ECS. TTM was not significantly different between two groups of newborns. The results indicate that mothers in VD and their newborns are in more oxidative stress than those who underwent ECS for delivery. Linking oxidative stress to severe neonatal diseases, it may be reasonable to assess whether antioxidant supplementation during pregnancy may reduce the frequency of neonatal diseases.

Correlation among cytokines, bronchopulmonary dysplasia and modality of ventilation in preterm newborns: improvement with melatonin treatment

Improved survival because of advances in neonatal care has resulted in an increased number of infants at risk for chronic lung disease. Even though the etiology of lung injury is multifactorial, recent animal and clinical data indicate that pulmonary damage depends in large part on the ventilatory strategies used. Ventilator-associated lung injury was believed to result from the use of high pressure, thus, the term barotraumas. This trauma is believed to involve free-radical damage. Oxidant injury is a serious cause of lung injury. In the present study, 110 newborns with respiratory distress syndrome were studied; 55 were treated with melatonin and the other 55 with placebo. All the subjects were mechanically ventilated with or without guaranteed volume. Proinflammatory cytokines [interleukin (IL)-6, IL-8 and tumor necrosis factor (TNF)-alpha] were measured in tracheobronchial aspirate and the clinical outcome was evaluated. Melatonin treatment reduced the proinflammatory cytokines and improved the clinical outcome. The beneficial action of melatonin presumably related to its antioxidative actions.

Oxidative stress in the fetal circulation does not depend on mode of delivery

OBJECTIVE

We tested whether neonates are subject to oxidative stress by comparing the susceptibility of umbilical blood lipids with copper-induced peroxidation.

STUDY DESIGN

Umbilical arterial and venous blood samples were drawn from 32 pregnant women who delivered by elective cesarean section (CS) and from 32 pregnant women who delivered by spontaneous vaginal delivery (SVD) in a tertiary care center. Oxidative stress was evaluated by spectrophotometric monitoring of copper-induced peroxidation of serum samples.

RESULTS

The lag preceding lipid peroxidation in umbilical arterial blood was shorter than the lag in umbilical venous blood, irrespective of mode of delivery (14.0+/-1.8 vs 50.6+/-8.25 min, P=.0004 in SVD group; 17.7+/-1.6 vs 39.2+/-7.6 min, P=.006 in CS group).

CONCLUSION

Umbilical arterial lipids are more susceptible to peroxidation than umbilical venous lipids, indicating high oxidative stress in the fetal circulation irrespective of mode of delivery.

Extracellular superoxide dismutase protects lung development in hyperoxia-exposed newborn mice

We tested the hypothesis that targeted transgenic overexpression of human extracellular superoxide dismutase (EC-SOD) would preserve alveolar development in hyperoxia-exposed newborn mice. We exposed newborn transgenic and wild-type mice to 95% oxygen (O2) or air x 7 days and measured bronchoalveolar lavage cell counts, and lung homogenate EC-SOD, oxidized and reduced glutathione, and myeloperoxidase. We found that total EC-SOD activity in transgenic newborn mice was approximately 2.5x the wild-type activity. Hyperoxia-exposed transgenic mice had less pulmonary neutrophil influx and oxidized glutathione than wild-type littermates at 7 days. We measured alveolar surface and volume density in animals exposed to 14 days more of air or 60% O2. Hyperoxia-exposed transgenic EC-SOD mice had significant preservation of alveolar surface and volume density compared with wild-type littermates. After 7 days 95% O2 + 14 days 60% O2, lung inflammation measured as myeloperoxidase activity was reduced to control levels in all treatment groups.

Evaluation of free radical status in CSF in childhood meningitis

The study was undertaken to investigate the possible role of free radicals and antioxidants in childhood meningitis. Sixty children suffering from acute bacterial meningitis (ABM) or tuberculous meningitis (TBM) according to their clinical and laboratory findings were enrolled in the study. The production of superoxide anions (O2.-), hydrogen peroxide (H2O2) and malondialdehyde (MDA) and the activities of xanthine oxidase (XO), superoxide dismutase (SOD) and glutathione peroxidase (GPx) were monitored in the study groups and findings compared with those in 20 age-matched controls. Children with ABM and TBM who died registered significant increases in the production of O2.- and MDA and in the activities of SOD and CPK compared with survivors. The rate of production of oxidants and MDA and the activities of XO, SOD and CPK were of a much higher magnitude in deceased ABM and in ABM survivors than in fatal TBM and survivors, respectively. The abnormalities in most of the biochemical parameters investigated were more marked in the children with ABM than in TBM and controls (p < 0.001). Increased MDA production and creatine phosphokinase (CPK) activity of different magnitudes in the two study groups suggest varying degrees of tissue damage. The alterations observed in 20 children who died (14 from ABM, 6 from TBM) revealed elevated levels of oxidants, antioxidants and toxicity markers, particularly in ABM patients, which suggests the possibility that natural or synthetic antioxidants might prevent disease progression and tissue damage in childhood meningitis.

Alterations in antioxidant status during neonatal sepsis

Septicaemia is a major threat to survival during the early stages of life. There are several reports that suggest that reactive oxygen species (ROs) play a role in a wide variety of diseases. We estimated the activity of xanthine oxidase (XO), malondialdehyde (MDA) content, creatine phosphokinase (CPK) activity, activities of key enzymatic antioxidants, such as superoxide dismutase (SOD), glutathione peroxidase (GPx) and peroxidase (PO), and non-enzymatic antioxidants, viz. uric acid (UA) and albumin (ALB), in 30 neonates with sepsis and 20 age-matched controls. The babies were categorized as preterm/term, early onset/late onset, and shock/without shock, as per clinical and laboratory investigations. The study was carried out to evaluate the status of antioxidant enzymes and non-enzymatic antioxidants with a view to suggesting the introduction of antioxidant therapy in neonatal sepsis. The activities of serum XO, CPK, SOD and GPx, and the content of MDA were found to be significantly elevated in the neonates with sepsis when compared with controls. Conversely, the activity of PO and the levels of UA and ALB were decreased. The septic, full-term neonates registered significantly higher CPK activity (70%) than the preterm septic neonates. However, infants with late-onset and shock sepsis had a significant decrease in CPK activity (p < 0.05) compared with their corresponding sub-groups. Likewise, UA levels were found to be 28% depressed (p < 0.05) in the babies with late-onset sepsis and 51% increased (p < 0.001) in babies with shock compared with their respective sub-groups. Neonates with septic shock also registered a significant elevation in GPx activity (28%) compared with those without shock. This study suggests increased production of ROs in neonates with sepsis, as evidenced by the positive regulation of XO, SOD and GPx activity. The elevation of antioxidant enzymes, however, was not so effective as to protect from cellular damage and thereby result in higher MDA production. It is evident that antioxidant therapy might be useful in the management of neonates with sepsis but further detailed clinico-biochemical investigations are required to define effective antioxidant therapy.