Maternal and fetal plasma vitamin E to total lipid ratio and fetal RBC antioxidant function during gestational development

Vitamin E and preterm infants

In evaluating vitamin E (VE) nutritional status of preterm infants, it is essential that any data should be compared with those of healthy term infants, and never with those of adults. Moreover, it should be evaluated in terms of gestational age (GA), not birth weight (BW), because placental transfer of most nutrients from mother to fetus is dependent on GA, not BW. Judging from the limited data during the last 75 years, there was no significant correlation between GA and VE concentrations in circulation or in the red blood cells (RBCs), leukocytes, and buccal mucosal cells. In addition, the oxidizability of polyunsaturated fatty acids (PUFAs) in plasma or RBCs, as targets for protection by VE chain-breaking ability, was lower in preterm infants. However, because of the minimal information available about hepatic VE levels, which is considered a key determinant of whole body VE status, the decision on whether VE status of preterm infants is comparable with that of term infants should be postponed. Clinical trials of VE supplementation in preterm infants were repeatedly undertaken to investigate whether VE reduces severity or inhibits development of several diseases specific to preterm infants, namely retinopathy of prematurity (ROP), bronchopulmonary dysplasia (BPD), and germinal matrix hemorrhage - intraventricular hemorrhage (GMH-IVH). Most of these trials resulted in a misfire, with a few exceptions for IVH prevention. However, almost all these studies were performed from 1980s to early 1990s, in the pre-surfactant era, and the study populations were composed of mid-preterm infants with GAs of approximately 30 weeks (wks). There is considerable difference in 'preterm infants' between the pre- and post-surfactant eras; modern neonatal medicine mainly treats preterm infants of 28 wks GA or less. Therefore, these results are difficult to apply in modern neonatal care. Before considering new trials of VE supplementation, we should fully understand modern neonatal medicine, especially the recent method of oxygen supplementation. Additionally, a deeper understanding of recent progress in pathophysiology and therapies for possible target diseases is necessary to decide whether VE administration is still worth re-challenging in modern neonatal intensive care units (NICUs). In this review, we present recent concepts and therapeutic trends in ROP, BPD, and GMH-IVH for those unfamiliar with neonatal medicine. Numerous studies have reported the possible involvement of reactive oxygen species (ROS)-induced damage in relation to supplemental oxygen use, inflammation, and immature antioxidant defense in the development of both BPD and ROP. Various antioxidants effectively prevented the exacerbation of BPD and ROP in animal models. In the future, VE should be re-attempted as a complementary factor in combination with various therapies for BPD, ROP, and GMH-IVH. Because VE is a natural and safe supplement, we are certain that it will attract attention again in preterm medicine.

Changes in the Mother-Placenta-Fetus System Under the Effect of α-Tocopherol in Albino Rats with Normal Pregnancy

The effects of α-tocopherol on the function of the mother-placenta-fetus system and structural changes in the placenta in normal pregnancy were studied in albino rats. The results indicated that inhibition of free radical processes by injections of α-tocopherol in normal pregnancy led to disorders in the feto-maternal circulation, which was proven by morphological changes in the placenta. The disorders in the uteroplacental circulation manifested in the development of small-for-date fetuses and erythrocytosis.

Concentrations of antioxidant vitamins in maternal and cord serum and their effect on birth outcomes

BACKGROUND

Emerging evidence indicates that maternal oxidative stress during pregnancy could impair fetal growth and that antioxidant vitamins (e.g. vitamins A, E and C) have a significant role in maintaining physiological processes of pregnancy and growth.

AIMS

To determine the concentrations of vitamins A, E, and C in pair-matched maternal and cord serum samples of neonate, and thus to investigate the relationship between maternal serum levels of these vitamins at delivery and birth outcomes.

METHODS

A total of 143 mother-neonate pairs were recruited into the cross-sectional descriptive study. Demographic information was investigated by questionnaire. After delivery, both cord and maternal blood were collected for quantification of serum levels of vitamins A, E and C by HPLC.

RESULTS

Maternal serum levels of vitamins A and E were significantly higher than those in cord serum. In contrast, vitamin C level in cord serum was significantly higher than that in maternal serum. Further, we found that maternal vitamin A status was significantly correlated to both birth weight (r=0.19, p=0.0419) and birth height (r=0.21, p=0.0311), and these were manifested by these findings: (i) per 250.2 g reduction in birth weight concomitant with 1 micromol/L increase in maternal serum vitamin A level (p<0.01; 95% CI: 56.9-451.5); and (ii) per 1% increase in the ratio of serum vitamin A level of neonate to mother concomitant with 0.8 cm increase in birth height (p=0.049; 95% CI: 0.004-1.639).

CONCLUSION

Maternal vitamin A, but not vitamins E and C, during pregnancy had a significant effect on birth outcomes. Further studies are necessary to investigate the role of these antioxidant vitamins in fetal growth at various gestation stages.

Effects of vitamin E on the response of the fetal middle cerebral artery to the pressure test

OBJECTIVE

To examine the effects of the maternal administration of vitamin E on the vasoreactivity of the middle cerebral artery (MCA) in preterm fetuses.

STUDY DESIGN

The vasoconstrictive response of the proximal segment of the MCA to brief and partial external occlusions of the umbilical vein (pressure test) was studied in 22 fetuses between 21 and 35 weeks of gestation, before, and 3 to 7 days after, the maternal administration of oral vitamin E (50 mg daily).

RESULTS

The vasoconstrictive activity of the MCA was eliminated in 15 fetuses (68.2%), unchanged in six (27.3%), and decreased in one (4.5%). In the latter seven cases, vasoconstriction of the proximal MCA in response to the pressure test was eliminated by increasing the vitamin E dosage to 100 mg/day.

CONCLUSION

Vitamin E administered to the mothers had a pronounced effect on the proximal MCA reactivity in preterm fetuses.

Pathophysiological basis for the prophylaxis of preeclampsia through early supplementation with antioxidant vitamins

Preeclampsia (PE) is a multisystem disorder that remains a major cause of maternal and foetal morbidity and death. To date, no treatment has been found that prevents the development of the disease. Endothelial dysfunction is considered to underlie its clinical manifestations, such as maternal hypertension, proteinuria, and edema; however, the precise biochemical pathways involved remain unclear. A current hypothesis invokes the occurrence of oxidative stress as pathogenically important, as suggested by the fact that in PE, the placental and circulating levels of lipid peroxidation products (F2-isoprostanes and malondialdehyde [MDA]) are increased and endothelial cells are activated. A potential mechanism for endothelial dysfunction may occur via nuclear transcription factor kappa B (NF-kappaB) activation by oxidative stress. Alternatively, the idea that the antiangiogenic placental soluble fms-like tyrosine kinase 1 factor (sFlt1) is involved in the pathogenesis of this disease is just emerging; however, other pathophysiological events seem to precede its increased production. This review is focused on evidence providing a pathophysiological basis for the beneficial effect of early antioxidant therapy in the prevention of PE, mainly supported by the biological effects of vitamins C and E.

Relationship between Alpha-Tocopherol Content in the Different Lipoprotein Fractions in Term Pregnant Women and in Umbilical Cord Blood

AIMS

To determine the concentration of vitamin E in normal maternal and umbilical cord blood pairs, and to study the relationship between vitamin E content in maternal lipoprotein fractions and umbilical cord blood.

METHODS

Fifty healthy pregnant women were recruited randomly at term and blood samples were drawn from the mothers at delivery and cord blood was obtained immediately postpartum. Vitamin E was determined by HPLC in plasma, in the different lipoprotein fractions and in the placenta. Plasma levels of triglycerides and cholesterol were also measured.

RESULTS

The concentration of vitamin E in umbilical cord plasma was 250 microg/dl, lower than in maternal plasma (1,460 microg/dl) (p < 0.001). A positive correlation was found between the vitamin E concentration in maternal plasma, LDL and VLDL and in the umbilical cord plasma. In contrast, no correlation was found between maternal HDL concentration and umbilical cord blood.

CONCLUSION

These results show that the concentration of vitamin E in umbilical cord blood is lower than in maternal plasma. LDL and VLDL seem to be the main source of vitamin E for the fetus.

The European perspective on vitamin E: current knowledge and future research

Vitamin E is indispensible for reproduction in female rats. In humans, vitamin E deficiency primarily causes neurologic dysfunctions, but the underlying molecular mechanisms are unclear. Because of its antioxidative properties, vitamin E is believed to help prevent diseases associated with oxidative stress, such as cardiovascular disease, cancer, chronic inflammation, and neurologic disorders. However, recent clinical trials undertaken to prove this hypothesis failed to verify a consistent benefit. Given these findings, a group of European scientists met to analyze the most recent knowledge of vitamin E function and metabolism. An overview of their discussions is presented in this article, which includes considerations of the mechanisms of absorption, distribution, and metabolism of different forms of vitamin E, including the alpha-tocopherol transfer protein and alpha-tocopherol-associated proteins; the mechanism of tocopherol side-chain degradation and its putative interaction with drug metabolism; the usefulness of tocopherol metabolites as biomarkers; and the novel mechanisms of the antiatherosclerotic and anticarcinogenic properties of vitamin E, which involve modulation of cellular signaling, transcriptional regulation, and induction of apoptosis. Clinical trials were analyzed on the basis of the selection of subjects, the stage of disease, and the mode of intake, dosage, and chemical form of vitamin E. In addition, the scarce knowledge on the role of vitamin E in reproduction was summarized. In conclusion, the scientists agreed that the functions of vitamin E were underestimated if one considered only its antioxidative properties. Future research on this essential vitamin should focus on what makes it essential for humans, why the body apparently utilizes alpha-tocopherol preferentially, and what functions other forms of vitamin E have.

Antioxidant vitamin levels in term and preterm infants and their relation to maternal vitamin status

BACKGROUND

Lipid peroxidation plays a vital role in the pathogenesis of many neonatal complications. Preterm babies are especially predisposed to lung diseases and retinopathy, probably due to a deficiency in their antioxidant systems. Vitamins E, A, and C are part of the natural antioxidant defense systems. We aimed to determine the levels of vitamins E, A, and C in maternal and cord blood plasma of term and preterm infants and to investigate the relationships between these levels.

METHODS

In the present study we determined vitamin E, A, and C levels in the umbilical cord blood of term (n = 30) and preterm (n = 22) infants and their mothers by HPLC. Blood samples were taken during delivery.

RESULTS

Levels of lipid soluble antioxidant vitamin E and A in cord blood were lower than maternal values (p <0.01, p <0.05, respectively). Conversely, the level of water-soluble vitamin C was higher in cord blood than in maternal level (p <0.05). Significantly higher levels of vitamins E, A, and C were found in term babies as compared with those born preterm (p <0.05).

CONCLUSIONS

There was a positive correlation between maternal and cord blood levels of vitamins E and A (r = 0.775, r = 0.725, respectively). In conclusion, preterm babies have fewer lipid-soluble antioxidant vitamins in their serum compared to term infants. Therefore, it is possible to postulate that preterm infants are more susceptible to oxidative stress.

Effects of early nutrition on free radical formation in VLBW infants with respiratory distress

OBJECTIVE

We studied the development of essential fatty acid deficiency (EFAD) and its effects together with those of vitamin E deficiency on the free radical formation of very low birth weight (VLBW) infants with respiratory distress.

METHODS

Infants were divided into three groups based on the way each was supplied with daily total energy intake: (1) by fat free parenteral nutrition only or by nutrition composed of (2) less than or (3) higher than 25% of total daily energy intake given in oral feeding. We measured plasma lipid parameters and autoxidative susceptibility (AOS) of red blood cells (RBCs).

RESULTS

Plasma concentrations of linoleic acid were low in all the groups. After at least 14 days of feeding, eicosatrienoic acid (EA) was not detected. One week after the introduction of oral feeding, the abnormal triene/tetraene ratio of the groups had decreased, but was not normalized. Vitamin E deficiency was associated with significantly increased AOS, but EFAD was not. The two factors together caused an increase of AOS, that was additive.

CONCLUSIONS

Our data confirm that EFAD increases AOS of RBCs in VLBW infants. We assume that prevention of EFAD in VLBW infants could decrease the prevalence of complications associated with free radical formation.

Influence of caesarean delivery and maternal factors on fat-soluble vitamins in blood from cord and neonates

We measured plasma and erythrocyte vitamin E (VE) and plasma vitamin A (VA) profiles in 48 full-term and 8 preterm pairs of neonates and their mothers at birth and we determined whether there is any relationship between maternal and umbilical cord for the nutrients measured. At the same time, we assessed the influence of the delivery type and neonate anthropometric measurements on maternal and cord blood VA and VE levels. We measured vitamin levels in vein and arterial blood in order to establish differences due to fetal metabolism. To determine the influence of pregnancy on vitamin levels, we compared the maternal results with data from a group of 13 non-pregnant women. Cord blood had lower plasma VE (arterial 275.8+/-71.7 microg/dl and vein 282.89+/-64.4 microg/dl values), erythrocyte VE (arterial 256.96+/-50.41 microg/dl packet cells and vein 257.41+/-44.35 microg/dl values), and VA levels (arterial 26.72+/-11.83 microg/dl and 27.15+/-10.05 microg/dl values) and a lower vitamin E/total lipids ratio (VE/LT) (arterial 1.60+/-0.4 and vein 1.62+/-0.3 values) than maternal blood (1474.62+/-424.51 microg/dl, 305.94+/-54.75 microg/dl packet cells, 41.03+/-18.83 microg/dl, 2.34+/-0.5, respectively). VA levels were higher in preterm than full-term neonates (P<0.05). Plasma and erythrocyte VE levels were not correlated in maternal blood but were correlated in neonates and infants (r>0.40; P<0.01). We found a good correlation between erythrocyte tocopherol of maternal and cord blood (r>0.40; P<0.01), although there was no correlation with plasma VE values. Cord vein plasma VE levels were higher than cord arterial blood measurements (P<0.01). The plasma VE and VE/LT of the mother and cord following vaginal delivery were higher than measurements from caesarean delivery (P<0.05), although erythrocyte levels were similar. The plasma VE level was higher in mothers at delivery than non-pregnant women.

Relationship of plasma carotenoids, retinol and tocopherols in mothers and newborn infants

OBJECTIVE

We studied the relationship between maternal and cord plasma concentrations of carotenoids, retinol, and tocopherols in normal mother-baby pairs.

METHODS

Healthy pregnant women (n = 10) were recruited at a Montréal hospital. Venous blood samples were collected from the mothers at delivery and cord blood was obtained immediately post partum from the umbilical vein after clamping of the cord. All deliveries were full term deliveries and all babies had normal birth weights. Maternal and umbilical cord blood samples were handled identically. Plasma was digested with lipase and plasma carotenoids were extracted and measured using HPLC.

RESULTS

Cord plasma concentration of carotenoids were significantly lower than that of maternal plasma (p < 0.001). There was a high correlation of lutein (r = 0.889, p = 0.006) and cryptoxanthin (r = 0.912, p = 0.0002) between maternal plasma concentrations and cord plasma concentrations. The concentrations of the hydrocarbon carotenoids, alpha-carotene and beta-carotene, were also correlated (r = 0.779, p = 0.0133, & r = 0.782, p = 0.0076, respectively) between maternal plasma and cord plasma. Whereas the plasma concentration of the acyclic carotenoid, lycopene, showed no correlation between the two groups, after adjustment for plasma triglycerides, the lycopene correlation between maternal and cord plasma was the highest (r = 0.975, p = 0.0001) of all the carotenoids tested. Cord plasma retinol concentration, which was 50% of that of maternal plasma, was also found to have no correlation with that of maternal plasma. Plasma concentration of alpha-tocopherol showed no correlation between two groups, whereas there was high correlation between cord and maternal gamma-tocopherol concentrations (r = 0.808, p = 0.0047).

CONCLUSION

The nutritional status of mothers affects the nutritional status of their babies for certain fat soluble nutrients.

Red blood cell vitamin E concentrations in fetuses are related to but lower than those in mothers during gestation. A possible association with maternal lipoprotein (a) plasma levels

OBJECTIVE

The purpose was to establish which blood characteristic of vitamin E status were highly correlated between mothers and fetuses during gestation.

STUDY DESIGN

Twenty-four pregnant women were selected because of suspicion of toxoplasmosis or other disease and malformation or intrauterine growth delay justifying cord blood puncture. After maternal and fetal blood was collected, analyses of plasma and red blood cell vitamin E contents were performed together with analyses of standard lipid parameters and lipoprotein (a) in maternal plasma and fatty acid compositions of maternal and fetal red blood cells.

RESULTS

The maternal population was characterized by a plasma lipid-normalized vitamin E mean content higher (3.5 mmol/mol lipids) than usually found in nonpregnant adults. There was no relationship between plasma and red blood cell vitamin E contents. This was also true for fetuses. When the vitamin E status of mothers was compared with that of fetuses, we found no correlation in plasma vitamin E in the whole population and in the high lipoprotein (a) (> 300 mg/L) and low lipoprotein (a) (< 300 mg/L) groups. In contrast, statistically significant correlations appeared between maternal and fetal red blood cell contents and red blood cell relative charges in vitamin E in the whole population, whereas still higher correlations occurred in the high lipoprotein (a) group (r = 0.94 for the red blood cell content). Improved correlations were also found in the high lipoprotein (a) group for the interrelationship between vitamin E and plasma lipid contents (cholesterol and triglycerides), whereas improvement was noted in the low lipoprotein (a) group by positive correlation between age and vitamin E red blood cell content or red blood cell relative charge.

CONCLUSION

Determination of red blood cell vitamin E and plasma lipoprotein (a) in mothers could be useful in antenatal blood analysis in cases of risk of prematurity at birth, to prevent peroxidative membrane damage in neonates, and > 85% of the mothers in the current population would benefit from vitamin E supplementation from the viewpoint of the fetal red blood cell vitamin E requirement in spite of the rather high maternal lipid-normalized vitamin E plasma content.

Amelioration of zidovudine-induced fetal toxicity in pregnant mice

The effects of zidovudine (AZT) on the fetus were investigated in pregnant mice by using parameters such as the number of fetuses, fetal size, and the fetal hepatic cell clonogenic assay. AZT caused dose-dependent toxicity to the fetus upon administration via drinking water to pregnant mice from days 1 to 13 of gestation. At the 0.5-mg/ml dose level, AZT caused a decrease in the number of fetuses to 12 from an average of 16.5 in control animals, and the fetal size (crown-rump length) was reduced from 10.5 to 8.5 mm. The CFU of the erythroid progenitor cell colonies derived from the fetal hepatic cells were decreased to 38% of that of the control, and the hematocrit dropped to 33.5 +/- 1.7 from a control value of 42.6 +/- 2.5. Concomitant administration of erythropoietin, vitamin E, or interleukin-3 to the AZT-treated pregnant mice caused a significant reversal in the AZT-induced toxicity to the fetus and to the mother's bone marrow. The success of therapeutic intervention was demonstrated by (i) restoration of the number of fetuses to the level of untreated controls, (ii) an increase in the size of fetuses to normal values, and (iii) an increase in hematocrit to > 40. The results suggest that AZT is toxic to the fetus in a dose-dependent manner and that treatment with erythropoietin, vitamin E, or interleukin-3 can ameliorate the AZT-induced fetal toxicity.