Determinants of umbilical cord arterial 8-iso-prostaglandin F2alpha concentrations

Sex-Specificity of Oxidative Stress in Newborns Leading to a Personalized Antioxidant Nutritive Strategy

Oxidative stress is a critical process that triggers several diseases observed in premature infants. Growing recognition of the detriment of oxidative stress in newborns warrants the use of an antioxidant strategy that is likely to be nutritional in order to restore redox homeostasis. It appears essential to have a personalized approach that will take into account the age of gestation at birth and the sex of the infant. However, the link between sex and oxidative stress remains unclear. The aim of this study was to find a common denominator explaining the discrepancy between studies related to sex-specific effects of oxidative stress. Results highlight a specificity of sex in the levels of oxidative stress markers linked to the metabolism of glutathione, as measured in the intracellular compartments. Levels of all sex-dependent oxidative stress markers are greater and markers associated to a better antioxidant defense are lower in boys compared to girls during the neonatal period. This sex-specific discrepancy is likely to be related to estrogen metabolism, which is more active in baby-girls and promotes the activation of glutathione metabolism. Conclusion: our observations suggest that nutritive antioxidant strategies need to target glutathione metabolism and, therefore, should be personalized considering, among others, the sex specificity.

Cord blood 8-isoprostane in the preterm infant

BACKGROUND

Cord blood 8-isoprostane (8-IP) is a marker of lipid peroxidation in the peripartum period. The independent association with degree of prematurity is not well-described.

OBJECTIVE

To identify patterns of lipid peroxidation among early, moderate and late preterm infants, and to understand how cord blood 8-IP varies with gestational age (GA) and related covariates.

STUDY DESIGN

Mother-infant pairs from 237 preterm births were studied as part of a longitudinal birth cohort study. GA subgroups were defined as extremely (≤28w), moderately (29-33w), and late (34-36w) preterm. Cord blood 8-IP was measured using EIA. Elevated 8-IP (4th quartile) was the primary outcome for multivariate logistic regression models, which were adjusted for maternal age/race, multiple gestation and infant gender, as well as other relevant covariates.

RESULTS

Elevated 8-IP was associated with extremely preterm birth (OR=4.31; 95% CI=1.90, 9.76), and was inversely associated with increasing GA (OR=0.88; 95% CI=0.80, 0.97). Elevated 8-IP was also associated with decreasing birth weight (BW), clinical chorioamnionitis, fetal inflammatory response of the placenta (FIR), and signs of perinatal depression. The GA on 8-IP association appeared to be modified by several maternal disease and fetal-infant factors. Lastly, the indirect associations between log-transformed 8-IP, GA and BW appeared to be most prominent for GA<30w and for BW<2000g.

CONCLUSION

Lipid peroxidation in preterm birth, and the relative influence of accompanying peripartum factors, varies according to degree of prematurity. These findings have important implications for the developmental regulation of antioxidant defense and its impact on neonatal outcomes.

Evidence-based pathology: umbilical cord coiling

The generation of a pathology test result must be based on criteria that are proven to be acceptably reproducible and clinically relevant to be evidence-based. This review de-constructs the umbilical cord coiling index to illustrate how it can stray from being evidence-based. Publications related to umbilical cord coiling were retrieved and analysed with regard to how the umbilical coiling index was calculated, abnormal coiling was defined and reference ranges were constructed. Errors and other influences that can occur with the measurement of the length of the umbilical cord or of the number of coils can compromise the generation of the coiling index. Definitions of abnormal coiling are not consistent in the literature. Reference ranges defining hypocoiling or hypercoiling have not taken those potential errors or the possible effect of gestational age into account. Even the way numerical test results in anatomical pathology are generated, as illustrated by the umbilical coiling index, warrants a critical analysis into its evidence base to ensure that they are reproducible or free from errors.

Lipid peroxidation in nuchal cord cases: implication for fetal distress

OBJECTIVE

To examine whether nuchal cord affects fetal lipid peroxidation and cord arterial blood gases, and thus to determine whether lipid peroxidation can show intrapartum distress.

METHODS

Pregnant women giving birth to a baby with nuchal cord (n = 32) formed the study group and others without this condition made up the control group (n = 36). The maternal malondialdehyde levels (MDA) before and after delivery as well as fetal umbilical cord MDA and arterial blood gases were measured in both the groups.

RESULTS

Mean cord MDA level was higher in the study group (p < 0.02) and was significantly higher than maternal MDA level after birth within the same group (p = 0.007). Cord blood gases as well as neonatal and labour characteristics showed no difference, except for variable decelerations, which were 2.2 times more common in the study group. Correlations between maternal MDA levels before and after delivery, umbilical cord MDA and arterial blood gases were non-significant in the nuchal cord group.

CONCLUSIONS

During delivery, nuchal cord increases lipid peroxidation without causing significant fetal acidemia. Level of lipid peroxidation may be a more sensitive indicator of intrapartum distress than results of acid-base studies.

Fish Oil Supplementation in Pregnancy Lowers F2-isoprostanes in Neonates at High Risk of Atopy

The anti-inflammatory properties of n-3 polyunsaturated fatty acids (n-3 PUFA) have suggested a potential role of these nutrients in dietary modification for prevention of allergic disease in early life. As oxidative stress is known to modify antigen presenting cell (APC) signalling and resulting immune responses, we examined the effects of maternal n-3 PUFA supplementation in pregnancy on markers of oxidative stress and APC function in neonates at high risk of allergy. Eighty-three pregnant atopic women were randomised to receive 4 g daily of either fish oil (n = 40) or olive oil (n = 43) capsules in a controlled trial from 20 weeks gestation until delivery. Plasma (cord blood) and urinary F2-isoprostanes were measured as markers of lipid peroxidation. Cord erythrocyte fatty acids and markers of APC function (HLA-DR expression and cytokine responses) were measured and related to levels of plasma F2-isoprostanes. Maternal fish oil supplementation lowered plasma (p < 0.0001) and urinary (p = 0.06) F2-isoprostanes. HLA-DR expression on APC was not different between the groups. In multiple regression analysis, 28.8% of the variance in plasma F2-isoprostanes was explained by positive relationships with erythrocyte arachidonic acid (AA) and monocyte HLA-DR expression and a negative relationship with erythrocyte eicosapentaenoic acid (EPA). This study shows that maternal supplementation with fish oil can attenuate neonatal lipid peroxidation. Clinical follow-up of these infants will help to determine if there are sustained effects on postnatal oxidative stress and expression of allergic disease.

Seasonal variability of oxidative stress markers in city bus drivers. Part II. Oxidative damage to lipids and proteins

The aim of the present study was to investigate the seasonal variability of markers of oxidative damage to lipids (15-F2t-isoprostane, 15-F2t-IsoP) and proteins (protein carbonyl levels) in 50 bus drivers and 50 controls from Prague, Czech Republic, and to identify factors affecting oxidative stress markers. The samples were collected in three seasons with different levels of air pollution. The exposure to environmental pollutants (carcinogenic polycyclic aromatic hydrocarbons, c-PAHs, particulate matter, PM2.5 and PM10, and volatile organic compounds, VOC) was monitored by personal and/or stationary monitors. For the analysis of both markers, ELISA techniques were used. The median levels of individual markers in bus drivers versus controls were as follows: 15-F2t-IsoP (nmol/mmol creatinine): winter 2005, 0.81 versus 0.68 (p<0.01); summer 2006, 0.62 versus 0.60 (p=0.90); winter 2006, 0.76 versus 0.51 (p<0.001); carbonyl levels (nmol/ml plasma): winter 2005, 14.1 versus 12.9 (p=0.001); summer 2006, 17.5 versus 16.6 (p=0.26); winter 2006, 13.5 versus 11.7 (p<0.001). Multivariate logistic regression identified PM levels measured by stationary monitors over a period 25-27 days before urine collection as a factor positively associated with lipid peroxidation, while protein oxidation levels correlated negatively with both c-PAHs and PM levels. In conclusion, markers of oxidative damage to lipids and proteins were increased in bus drivers in winter seasons, but not in summer. Lipid peroxidation was positively correlated with c-PAHs and PM exposure; protein oxidation correlated negatively and was highest in summer suggesting another factor(s) affecting protein carbonyl levels.

Plasma levels of 15-F(2t)-isoprostane in newborn infants are affected by mode of delivery

OBJECTIVE

To investigate how the mode of delivery affects the level oxidative stress in newborns.

DESIGN AND METHODS

15-F(2t)-isoprostane, as index of oxidative stress, was measured in umbilical cord plasma samples from 37 infants born after vaginal delivery or caesarian section, using specific immuno-affinity extraction and immunoassay.

RESULTS

15-F(2t)-isoprostane levels were higher in infants born after vaginal delivery (n=18) compared to those delivered by elective caesarian section (n=19).

CONCLUSIONS

15-F(2t)-isoprostane is a sensitive biomarker of fetal oxidative stress during labor.

Fetal effects of maternal supplementary oxygen during Caesarean section

PURPOSE OF REVIEW

This review summarises the current issues, knowledge and research on the effects of maternal supplementary oxygen therapy on the fetus during Caesarean section. This is a controversial subject since supplementary oxygen has the potential to confer both benefits and also harm to the fetus, depending on the circumstances.

RECENT FINDINGS

For elective Caesarean section, breathing room air under regional anaesthesia or 30% oxygen under general anaesthesia is not associated with either maternal or fetal hypoxia. A prolonged uterine-incision-to-delivery (U-D) interval of up to 310 s is not a major factor per se for development of fetal hypoxia or acidosis, and no benefits could be derived from breathing supplementary oxygen in this situation. Although it appears rational to provide supplementary oxygen in the presence of a hypoxic or compromised fetus, to achieve meaningful increases in fetal oxygenation, a very high inspired oxygen fraction (FiO2) is required. However, it still remains unclear whether this is beneficial for the fetus. The process of damage to the hypoxic fetus is one of oxidative stress mediated by free radicals generated during reperfusion (ischaemia-reperfusion injury). Independently, hyperoxia from breathing supplementary oxygen also induces formation of free radicals by direct mitochondrial electron transfer. Although hyperoxia could lessen the severity of fetal hypoxia, there is also a theoretical risk of an enhanced reperfusion injury. This issue has not been resolved in a clinical study, but an animal study reported enhanced formation of free radicals after an episode of fetal hypoxia in the group receiving supplementary oxygen.

SUMMARY

For elective Caesarean section, current evidence suggests that supplementary oxygen is unnecessary. For emergency Caesarean section, further data are required before a conclusion can be made for its beneficial and adverse effects. Improvement of fetal oxygenation should be the primary objective, and this is achievable in the short term by using a very high FiO2. Although there is also a possibility of an enhanced reperfusion injury, particularly in the preterm and non-labouring patients, further data are necessary before a conclusion can be made.

Lipid peroxidation in cord blood and neonatal outcome

BACKGROUND

Periventricular-intraventricular hemorrhage, necrotizing enterocolitis, chronic lung disease and retinopathy of prematurity have been referred to as oxygen radical diseases (ORD) because they are thought to be related to excess oxidant stress relative to anti-oxidant defenses in premature infants. 8-Isoprostane is a product of lipid peroxidation that can be used as a measure of free radical exposure or injury. The aim of the present study was to determine whether fetal oxidant stress is associated with adverse effects in preterm infants.

METHODS

Mothers delivering at gestational age <37 weeks were recruited. Umbilical arterial and venous cord blood samples were collected and 8-isoprostane levels measured. Levels of 8-isoprostane in cord blood were correlated with maternal and perinatal variables, neonatal mortality, and the development of one or more ORD.

RESULTS

Umbilical cord venous, but not arterial, 8-isoprostane levels were associated with mortality and the development of one or more of the ORD. After controlling for gestational age, for each unit change in the log value of 8-isoprostane in venous cord blood the odds of mortality were 12 (95% confidence interval [CI]: 1-223) and oxygen radical disease were 2.7 (95%CI: 1-7.2). Isoprostane levels were not related to gender, method of delivery, use of maternal magnesium or steroids, pregnancy-induced hypertension, or delivery room resuscitation.

CONCLUSION

Oxidant stress in utero may be an important determinant of mortality and morbidity in preterm infants. Elevated umbilical venous isoprostane levels suggest that oxidative injury to maternal and placental tissues predispose to adverse neonatal outcomes.

Ischemia-modified albumin levels in cord blood: A case-control study in uncomplicated and complicated deliveries

BACKGROUND

In the past few years ischemia modified albumin (IMA) has emerged as a new biomarker of ischemia in the area of monitoring acute coronary syndromes. We hypothesized that reduced blood flow, such as that resulting from vascular compression in complicated labors or placental ischemia, may increase IMA. IMA level in cord blood could then serve as an indicator of fetal hypoxia and fetal tissue ischemia and serve as a biomarker of the severity of these conditions.

METHODS

We performed a case-control study with 26 newborns (12 normal term deliveries, Apgar 8-9; and 14 complicated labors or pre-term deliveries, Apgar 5-8). Complications were: prematurity (3), fetal distress (6), premature rupture of membranes (6), intrauterine growth retardation (3), pre-eclampsia (1). We also studied 30 healthy adults. IMA was measured in serum from cord blood (or venous blood for adults) by the decrease in cobalt 2+ binding.

RESULTS

IMA levels in neonates from non-complicated deliveries are significantly higher (45%, p < 0.005) than those of an adult control population, suggesting that IMA may increase as a consequence of labor. This increased IMA in neonates could not be accounted for by the changes in albumin concentration. It is conceivable that a transient increase in IMA reflects, in part, transient localized tissue ischemia due to the external forces exerted on the fetus during the mechanism of labor. IMA levels in cord blood from neonates from complicated deliveries are 50% higher than in neonates from uneventful deliveries (p < 0.05) while their albumin values are not significantly different (32 +/- 3 vs. 33 +/- 2 g/l). Moreover, IMA seems to be responsive to hypoxic fetal distress, showing values more than 300% higher in cases of severe fetal hypoxia (Apgar 5 n = 2: 2.19 +/- 0.01 AU vs. 0.64 +/- 0.24 for controls). IMA values did not correlate significantly with either lipoperoxides or CRP levels.

CONCLUSIONS

This is the initial reporting of IMA levels in cord blood from normal deliveries compared to healthy adult ranges and neonates from complicated deliveries. Cord blood IMA levels may be an indicator of fetal ischemia and/or hypoxia. This test could become an additional biomarker to be used in conjunction with other markers and/or clinical scores aimed at determining risk of neurological complications of fetal distress.

Age-related differences in vasoconstrictor responses to isoprostanes in piglet pulmonary and mesenteric vascular smooth muscle

Isoprostanes are prostaglandin (PG)-like compounds produced nonenzymatically by free radical-catalyzed peroxidation of arachidonic acid. Isoprostanes evoke potent vascular effects but their actions in the neonatal vasculature are poorly known. We aimed to study the effects of 8-iso-PGE(1), 8-iso-PGE(2), 8-iso-PGF(1alpha), 8-iso-PGF(1beta), 8-iso-PGF(2alpha), and 8-iso-PGF(2beta) in pulmonary arteries (PA), pulmonary veins (PV), and mesenteric arteries (MA) from newborn and 2-wk-old piglets. Isoprostanes produced concentration-dependent contractions of PA, PV, and MA (magnitudes up to 1.5- to 2-fold greater than the responses to 62.5 mM KCl) but they were markedly less potent vasoconstrictors than the thromboxane A(2) (TXA(2)) mimetic U46619. Neonatal PA were more sensitive to 8-iso-PGF(1alpha), 8-iso-PGF(1beta), and 8-iso-PGF(2beta) than 2-wk-old PA. Neonatal PV were more sensitive to 8-iso-PGE(2) and 8-iso-PGF(1alpha), and neonatal MA were more sensitive to 8-iso-PGE(2), 8-iso-PGF(1alpha), 8-iso-PGF(1beta), 8-iso-PGF(2alpha), and 8-iso-PGF(2beta) than the corresponding 2-wk-old vessels. The sensitivity to U46619 decreased with postnatal age in MA but did not change in PA and PV. The contractile responses to all the isoprostanes and to U46619 were reverted by the TXA(2) receptor (TP) antagonist SQ 29,548. Moreover, isoprostane-evoked contractions in 2-wk-old PA were reduced by inhibitors of tyrosine kinase (genistein) and Rho kinase (Y 27632 and hydroxyfasudil) but not by inhibitors of protein kinase C (chelerythrine), mitogen-activated protein kinase kinase (PD 98059) or p38-kinase (SB 203580). In conclusion, isoprostanes produced compound-, tissue-, and age-dependent constriction of neonatal porcine pulmonary and mesenteric vascular smooth muscle. Isoprostane-evoked PA vasoconstriction involved TP receptors and activation of tyrosine kinases and Rho kinases.

Meconium-stained liquor during labor is associated with raised neonatal cord blood 8-iso-prostaglandin F2alpha concentration

OBJECTIVE

The purpose of this study was to compare the umbilical arterial 8-iso-prostaglandin F2alpha, concentrations between pregnancies that were complicated by moderate or thick meconium-stained liquor and those with clear liquor.

STUDY DESIGN

Umbilical cord arterial blood samples were collected from 247 singleton pregnancies with either moderate or thick meconium-stained liquor at any stage of labor or clear liquor at all stages of labor for the determination of the total 8-iso-prostaglandins F2alpha concentration.

RESULTS

The median total 8-iso-prostaglandins F2alpha concentration of the meconium-stained liquor group was significantly higher than that of the control group (719.2 vs 115.8 pg/mL). Among the meconium-stained liquor group, those who had a change from "clear liquor" at early labor to "moderate/ thick meconium-stained liquor" at late first stage or at delivery (late meconium-stained liquor group) had higher 8-iso-prostaglandins F2alpha concentration, compared with those who had moderate/ thick meconium-stained liquor since early labor (early meconium-stained liquor group; 959.8 vs 499.9 pg/mL). With the use of multiple regression analysis, meconium-stained liquor, duration of second stage of labor, and abnormal fetal heart tracings were independent determinants of cord blood 8-iso-prostaglandins F2alpha concentration.

CONCLUSION

Moderate or thick meconium-stained liquor is an independent factor for increased oxidative stress in pregnancy.

Quantifying F2-isoprostanes in umbilical cord blood of newborn by gas chromatography-mass spectrometry

We attempted to improve the extraction procedures to determine the F(2)-isoprostanes in plasma of umbilical cord arterial and venous blood by gas chromatography mass spectrometry. Plasma samples were deproteinized and hydrolyzed; free and esterified F(2)-isoprostanes were extracted by solid-phase extraction columns with citric acid/methanol/cyclohexane and ammonia solution/methanol and then derivatized by PFBBr and BSTFA. Concentrations of total plasma F(2)-isoprostanes eluted at the retention time of an internal standard of 8-iso-prostaglandin F(2alpha)-D(4) were quantified. The absolute recovery was 83+/-1.9% (95% confidence). Intraassay precision and interassay precision were lower than 1.0%. Analytical accuracy was 99.0+/-0.4% (95% confidence). Linearity, r(2), over the concentration range of 10 to 5000 pg/ml of spiked 8-iso-prostaglandin F(2alpha) in plasma was 0.9985. The method detection limit was 21 pg/ml (99% confidence) and the limit of quantitation was approximately 4 pg/ml. Analysis of 200 neonatal cord blood samples revealed few overlapping peaks causing interference in the elution of the F(2)-isoprostanes. With the use of an autosampler and one technician, 48 samples can be completed within 24h with 6h of actual hands-on work. This method could be potentially employed for routine analysis of plasma F(2)-isoprostanes in clinical laboratories.

Increased urinary F2-isoprostanes in patients with Crohn's disease

OBJECTIVES

Reactive oxygen metabolites have been suggested to participate in the pathogenesis of Crohn's disease, but the evidence supporting this contention in vivo is incomplete. Isoprostaglandin F2alpha type III (iPF2alpha-III, or 15-F2t-IsoP) is a prostaglandin F2alpha isomer produced in vivo by free radical-catalyzed peroxidation of arachidonic acid. We aimed to investigate urinary iPF2alpha-III concentrations as an index of lipid peroxidation in 23 patients with Crohn's disease compared with 23 healthy controls, and to test whether lipid peroxidation correlates to clinical relapse and inflammation.

METHODS

Urinary iPF2alpha-III was measured by gas chromatography/electronic impact mass spectrometry.

RESULTS

Urinary iPF2alpha-III concentrations were significantly higher in patients with Crohn's disease than in healthy controls (median [range] = 130 [38-622] vs 91 [35-152] pmol/mmol of creatinine, respectively; p < 0.01). There was a trend toward significance for patients with clinical relapse versus patients with clinical remission (median [range] = 155 [38-622] vs 96 [64-253] pmol/mmol of creatinine, respectively; p = 0.09). A significant correlation was found between urinary iPF2alpha-III and plasma C-reactive protein concentrations, suggesting a link between lipid peroxidation and inflammation.

CONCLUSION

This study provides evidence of increased lipid peroxidation in patients suffering from Crohn's disease, especially in patients with clinical relapse. iPF2alpha-III quantification has to be investigated as a prognosis biomarker in patients suffering from Crohn's disease.