Fructose in fetal cord blood and its relationship with maternal and 48-hour-newborn blood concentrations

BACKGROUND

Studies have suggested that different non-glucose sugars and sugar alcohols play a role in placental and fetal metabolism. However, the role of fructose in the fetal and newborn metabolism is unclear and studies are scarce.

AIM

Our objective was to investigate the presence of fructose in umbilical cord blood in full-term gestation and its relationship with maternal and 48-hour-old- newborn blood concentrations, to evaluate fructose production by the fetus and newborn infant.

METHODS

Blood fructose and glucose concentrations were determined by HPLC in 26 paired samples of maternal blood, umbilical cord vein, and peripheral newborn blood at 48 h after birth. ANOVA, the Friedman Analysis of Variance on Ranks and the Pearson correlation with p<0.05 were used.

RESULTS

Fructose concentration in umbilical cord blood was higher than maternal blood (p=0.024), suggesting endogenous fructose production by the fetal-placental unit via the sorbitol pathway. Fructose concentrations were higher in newborns at 48 h after birth than in the fetal umbilical cord blood (p=0.004), suggesting that fructose production is a continuous process from fetus to newborn.

CONCLUSIONS

Fructose production by the sorbitol pathway, present in the fetus and newborn, is an alternative pathway in glucose metabolism probably used to maintain redox balance in the fetus. We suggest that endogenous fructose, similar to dietary ingested fructose, under physiological conditions produces the backbone for triacylglycerol and lipid synthesis in the fetus and newborn. Therefore the route for metabolizing fructose is already present in the early steps of human development.

Conductive hearing loss in children with bronchopulmonary dysplasia: a longitudinal follow-up study in children aged between 6 and 24 months

AIMS

To determine the occurrence of isolated and recurrent episodes of conductive hearing loss (CHL) during the first two years of life in very low birth weight (VLBW) infants with and without bronchopulmonary dysplasia (BPD). STUDY DESIGN, SUBJECTS AND OUTCOME MEASURES: In a longitudinal clinical study, 187 children were evaluated at 6, 9, 12, 15 18 and 24 months of age by visual reinforcement audiometry, tympanometry and auditory brain response system.

RESULTS

Of the children with BPD, 54.5% presented with episodes of CHL, as opposed to 34.7% of the children without BPD. This difference was found to be statistically significant. The recurrent or persistent episodes were more frequent among children with BPD (25.7%) than among those without BPD (8.3%). The independent variables that contributed to this finding were small for gestational age and a 5 min Apgar score.

CONCLUSIONS

Recurrent CHL episodes are more frequent among VLBW infants with BPD than among VLBW infants without BPD.

Blood galactose and glucose levels in mothers, cord blood, and 48-hour-old breast-fed full-term infants

BACKGROUND

Although galactose is an important component in human lactose, there are few reports of its role in the newborn metabolism.

OBJECTIVE

To determine the relationship of blood galactose and glucose levels in mothers, cord blood, and breast-fed full-term newborn infants.

METHODS

Maternal and cord vein blood samples were obtained from 27 pregnant women at delivery, and from their breast-fed, full-term newborns 48 h later. Galactose and glucose were determined by HPLC. Statistical analysis used ANOVA and Pearson correlation with p < 0.05.

RESULTS

Maternal galactose concentrations (0.08 +/- 0.03 mmol/l) were similar to cord blood galactose (0.07 +/- 0.03 mmol/l; p = 0.129). However, newborn blood galactose (0.05 +/- 0.02 mmol/l) was significantly lower than both cord (p = 0.042) and maternal blood (p = 0.002). Maternal blood glucose levels (4.72 +/- 0.86 mmol/l) were higher than cord blood (3.98 +/- 0.57 mmol/l; p < 0.001), and cord blood concentrations were higher than newborn blood levels (3.00 +/- 0.56 mmol/l; p < 0.001); all values expressed as mean +/- SD. Significant correlation was only seen between maternal and cord blood galactose levels (r = 0.67; p < 0.001) and glucose levels (r = 0.38; p = 0.047).

CONCLUSION

The association and similarity between maternal and cord blood galactose levels suggest that the fetus is dependent on maternal galactose. In contrast, the lower galactose levels in newborn infants and a lack of association between both suggest self-regulation and a dependence on galactose ingestion.

Fractional sodium excretion, urinary osmolality and specific gravity in preterm infants fed with fortified donor human milk

OBJECTIVE

This research was performed with the objective of investigating the renal effects on premature newborn infants of fortifying banked donor human milk.

METHODS

Clinical intervention trial, of the before-and-after type, involving 28 premature newborn infants split into two groups by postconceptional age at the start of the study: GI < 34 weeks (n = 14) and GII >or= 34 weeks (n = 14), and assessed at three sample points: S1, on unfortified donor human milk, S2, after 3 days, and S3, after 10-13 days on fortified donor human milk. Nutrient intake, weight gain, fractional sodium excretion, urinary osmolality and specific density were compared with two-way ANOVA for repeated measures.

RESULTS

Fluids, energy and sodium intakes were similar for both groups, and weight gain was satisfactory. Among the preterms with < 34 weeks postconceptional age, serum sodium was lower at the end of the study and the fractional sodium excretion was elevated at the start and at the end of the study (S1 = 2.11+/-1.05; S2 = 1.25+/-0.64; S3 = 1.62+/-0.88), with a significant difference in relation to GII (S1 = 1.34+/-0.94; S2 = 0.90+/-0.54; S3 = 0.91+/-0.82). Osmolality and urinary specific density were normal, with no differences between groups or collection dates.

CONCLUSIONS

No adverse effects on the renal function of these preterms were detected as a result of being fed fortified donor human milk.

[Minerals in the nutrition of extremely low birth weight infants]

OBJECTIVE

To review the literature on the role of calcium, phosphorus and trace elements in the nutrition of extremely low birth weight infants, considering their importance for metabolism, bone mineralization and as dietary components.

SOURCES OF DATA

MEDLINE, the Cochrane Database of Systematic Reviews and books on nutrition were searched between 1994 and 2004. Original research studies and reviews were selected.

SUMMARY OF THE FINDINGS

Extremely preterm infants are frequently growth-restricted at hospital discharge as a consequence of difficulties in the provision of adequate nutrition. The long-term effects of this growth restriction need to be determined. There is a paucity of studies about the role of minerals, especially micronutrients, in the nutrition of extremely preterm infants. The principal focus of this review was on calcium and phosphorus metabolism, bone mineralization and parenteral and enteral supplementation. A critical evaluation of post-discharge nutrition and its influence upon growth and bone mineralization was presented. Selenium and zinc requirements and the role of selenium as an antioxidant with possible effects on free radical diseases of the preterm infant were discussed.

CONCLUSIONS

Extremely preterm infants have low mineral reserves and, as a consequence, may have deficiencies in the postnatal period if they do not receive parenteral or enteral supplementation. More studies are needed to elucidate the actual requirements and the appropriate supplementation of micronutrients. There are controversies about the outcome and the influence of post-discharge nutrition on bone disease of prematurity.