Plasma levels of retinol, retinol-binding protein, all-trans beta-carotene and cryptoxanthin in low birth weight infants

Maternal smoking decreases antioxidative status of human breast milk

OBJECTIVE

To evaluate the influence of maternal smoking on antioxidative capacity and intensity of oxidative damage in breast milk.

STUDY DESIGN

The study group (n=30) was comprised of postpartum women who declared smoking more than five cigarettes per day during pregnancy and lactation (confirmed by the urinalysis of cotinine concentration), and their newborns. Control group included 29 non-smoking postpartum women and their newborns. Colostrum samples were collected on the 3rd day after delivery and breast milk samples between the 30th and the 32nd day after delivery. Morning maternal and neonatal urine samples were obtained on the day of the mature milk sampling. Isoprostane concentrations in colostrum/mature milk and urine were determined immunoenzymatically. Total Antioxidant Status (TAS) of colostrum/breast milk was determined by Rice-Evans and Miller method.

RESULT

Colostrum TAS in smokers was significantly lower than in non-smokers (P=0.006). In both groups, the TAS of mature milk was higher compared with colostrum, but significant differences were observed amongst smokers only (P=0.001). In smokers the isoprostane concentration of mature milk was significantly higher than the colostrum concentration (P=0.001). Significant inverse correlation between maternal urinary isoprostane concentration and the TAS of mature breast milk was observed in smokers (R=-0.525, P=0.023), but not in non-smokers (R=0.161, P=0.422).

CONCLUSION

This study revealed that maternal smoking triggers harmful effects on an infant by impairing pro-oxidant-antioxidant balance of breast milk.

The effect of tobacco smoking during pregnancy on plasma oxidant and antioxidant status in mother and newborn

OBJECTIVE

The aim of the study was to estimate the effect of tobacco smoking during pregnancy on oxidative damage and antioxidant defence in matched samples of maternal blood and cord blood.

STUDY DESIGN

Healthy, pregnant women (n=140) were divided into non-smoking and smoking groups according to the concentration of cotinine in serum and urine. Oxidative damage was measured through levels of malondialdehyde (MDA) and plasma antioxidant status was evaluated by measuring concentrations of total radical trapping parameters (TRAP) and selected antioxidants (β-carotene, vitamin A, vitamin E, uric acid). Statistical analysis was done using the SAS System for Windows (SAS Institute, Cary, NC).

RESULTS

In the course of pregnancy the concentration of MDA increased, but to higher values in smoking women than in non-smoking ones. It was accompanied by significantly lower TRAP in the smoking group than in the controls (p<0.05). Plasma concentration of uric acid (p<0.05) and antioxidant vitamins E (p<0.01), A and β-carotene (p<0.0001) were all reduced in smokers as compared with non-smoking pregnant women especially in the third trimester. Concentration of MDA in plasma of cord blood of newborns of smoking mothers was significantly higher (p<0.01) but the antioxidant defence was lower (p<0.0001) than in non-smoking ones. It was particularly pronounced for β-carotene (32%; p<0.0001) and vitamin A (28%; p<0.001). A significant negative correlation was found between MDA and TRAP levels of maternal plasma (non-smoking and smoking: r=-0.50, p<0.0001) and cord plasma (non-smoking: r=-0.54, p=0.0057; smoking: r=-0.71, p=0.0004) in all the study subjects. Total antioxidant status positively correlated with concentrations of uric acid and vitamin E in non-smoking and smoking mothers as well as their newborns.

CONCLUSION

Tobacco smoke enhances lipid peroxidation and depletes antioxidant potential in the plasma of pregnant women and umbilical cord blood. Therefore smoking during pregnancy may stimulate free radical damage in the mother and the growing fetus.

Low plasma retinol concentrations increase the risk of developing bronchopulmonary dysplasia and long-term respiratory disability in very-low-birth-weight infants

BACKGROUND

The effect of inadequate vitamin A during the neonatal period on lung status is still unknown.

OBJECTIVE

We tested the hypothesis that low plasma retinol concentrations during the first month of life are independently associated with bronchopulmonary dysplasia (BPD) and long-term respiratory morbidity at 6 mo gestationally corrected age (ie, the age the infant would be had the pregnancy gone to term).

DESIGN

Respiratory outcome information was obtained to 6 mo corrected age for a historical cohort of very-low-birth-weight neonates (<1250 g) who were admitted to intensive care over a 7-y period. Neonates with one or more plasma measurements of retinol concentrations < 0.35 micromol/L (<100 microg/L) on days 1-28 were classified as having low vitamin A. BPD was defined at day 28 by clinical and radiologic criteria and by use of supplemental oxygen at 36 wk postmenstrual age (PMA). Dependence on supplemental oxygen was used to identify long-term respiratory disability at 6 mo corrected age. Multivariate logistic regression analyses were conducted.

RESULTS

Of the 350 study infants, 192 (55%) had low vitamin A status. BPD occurred in 52% of survivors at day 28 (173/331) and at 36 wk PMA (147/285). Fourteen percent (33/244) required oxygen support at 6 mo corrected age. Adjusted odds ratios of BPD with low vitamin A were 3.5 (95% CI: 1.7, 7.2) at day 28 and 1.7 (1.0, 2.7) at 36 wk PMA. At 6 mo corrected age, the adjusted odds ratio was 2.6 (1.1, 6.4) for respiratory disability with low vitamin A.

CONCLUSION

Poor vitamin A status during the first month of life significantly increased the risk of developing BPD and long-term respiratory disability.

Postnatal changes in maternal and neonatal plasma antioxidant vitamins and the influence of smoking

OBJECTIVE

To study the postnatal changes in the plasma concentrations of fat soluble antioxidant vitamins and malondialdehyde (MDA) in mothers and their newborns and their relation to smoking.

DESIGN

Prospective cohort study.

SETTING

Tertiary perinatal centre.

SUBJECTS

Eighteen non-smoking and 14 smoking mothers and 33 infants.

MAIN OUTCOME MEASURES

Plasma concentrations of vitamins E, A, and beta-carotene and MDA were measured in mothers and infants at delivery and on day 4 post partum.

RESULTS

Neonatal plasma levels of vitamins E, A, and beta-carotene were significantly lower than maternal levels both at delivery and on day 4 in both groups. There was a significant postnatal increase in plasma vitamin E levels in smoking mothers and neonates of both groups. A significant postnatal increase in maternal, but not neonatal, plasma vitamin A was noted in both groups. Cord plasma vitamin E levels were significantly lower in infants of smoking mothers (mean 4.7 v 6.5 micromol/l, p = 0.041). Plasma MDA was paradoxically lower in smoking mothers at delivery (3.19 v 4.01 micromol/l, p = 0.03) and on day 4 (1.37 v 3.29 micromol/l, p = 0.005) and in infants of the smoking group on day 4 (2.18 v 3.12 micromol/l, p = 0.014). Also, there was a significant postnatal fall in plasma MDA levels on day 4 in mothers and infants in the smoking group.

CONCLUSIONS

The postnatal changes in plasma vitamin E were more pronounced in the smoking group. The postnatal changes in plasma vitamins A and beta-carotene were similar in both groups. The rapid decline in plasma MDA in smoking mothers and their infants suggests withdrawal of oxidative stress from smoking around delivery. This coincided with the increase in plasma vitamin E.