Lipid Peroxidation in Cord Blood at Birth: A Marker of Fetal Hypoxia during Labour

Abstract

Objective: This prospective study examined purine metabolism in relation to free oxygen radical activity, as reflected by lipid peroxide levels in umbilical cord blood at birth. Setting: Departments of Obstetrics and Gynaecology and of Chemical Pathology, the Chinese University of Hong Kong, Hong Kong, and Purine Research Laboratory, UMDS of Guy’s and St. Thomas’ Hospitals, London, UK. Methods: Umbilical cord arterial and venous blood samples were collected from 132 singleton term deliveries for determination of hypo-xanthine, xanthine, inosine, uric acid, organic hydroperoxides (OHP) and malondialdehyde. Oxygen saturation, pO₂, PCO₂, pH, and base excess (BE) were also measured. Results: There was a significant correlation between umbilical arterial and venous levels of hypoxanthine, xanthine, inosine, uric acid and all acid-base parameters (p < 0.001). Significant arteriovenous differences were observed for all parameters with the exception of inosine, uric acid and OHP. Umbilical arterial xanthine and potassium correlated significantly with OHP, but hypoxanthine, inosine and uric acid did not. In 13 babies classified as severely asphyxiated at birth (umbilical arterial pH < 7.15, BE < -8), xanthine and OHP levels were significantly elevated when compared with non-asphyxiated babies. No significant differences were observed for hypoxanthine, inosine or uric acid. Conclusion: The findings indicate that OHP, either in cord arterial or venous blood, is the best marker of free oxygen radical activity in the fetus, and that this correlates with other evidence of cellular hypoxia-reperfusion injury. We propose OHP is a better measure of perinatal outcome than either acid-base balance or hypoxanthine.

The influence of maternal smoking on maternal and newborn oxidant and antioxidant status

“…Plasma MDA levels may vary from day to day within the subject and it can be acutely altered by smoking within hours [20]. Because of the rapid metabolism and wide variation of MDA, it is proposed that plasma organic hydroperoxides would be a better marker of free oxygen radical activity in the fetus [25].…”

Lipid Peroxidation and Antioxidant Status in Maternal and Cord Blood

“…The positive correlation between the cord blood and maternal blood lipid peroxide levels shows us that the fetus may be affected by the maternal oxidative stress. Intracellular hypoxia causes a decrease in the ATP levels and an increase in the ATP breakdown products [19,20]. A decrease in the ATP levels causes a destruction of the membrane sodium pump activity and oxidative phosphorylation fails.…”

“…This may trigger the lipid peroxidation. Rogers et al [20] showed that the increase in oxygen free radicals in the fetus is a sign of cellular hypoxia and reperfusion damage. On the other hand, Harkness et al [21] suggested that, in newborns with asphyxia, cord blood hypoxanthine levels were elevated and an elevated hypoxanthine catabolism by xanthine oxidase might be responsible for the increases in the free radical production.…”

Lack of Prognostic Significance of Early Elevated Serum Uric Acid Levels in Low Birthweight Infants

“…Several authors have discounted the role of ischemia or hypoxia specifically at the time of birth in relation to the subsequent development of cerebral palsy, particularly in the preterm population, which is at highest risk for brain injury [2]. However, both direct brain injury as manifested by intraventricular hemorrhage (IVH) and periventricular leukomalacia (PVL), or later developmental abnormalities, have been correlated with some short-lived biochemical markers of ischemia or reperfusion, indicating that some proportion of neurological injury may relate to events near the time of birth [3][4][5]. One such marker is uric acid (UA) [6][7][8].…”