Nerve Growth Factor Levels in Term Human Infants: Relationship to Prenatal Growth and Early Postnatal Feeding

Maternal diabetes decreases the expression of α2-adrenergic and M2 muscarinic receptors in the visual cortex of male rat neonates

AIMS

This study investigates the impact of maternal diabetes on the expression of α2-adrenergic and M2 muscarinic receptors in the primary visual cortex of male offspring born to diabetic rats.

MAIN METHODS

In adult female rats, a single dose of intraperitoneal streptozotocin (STZ) was used to induce diabetes (Diabetic group). Diabetes was controlled with insulin in the Insulin-treated group. Female rats in the control group received normal saline instead of STZ. Male newborns were euthanized at P0, P7, and P14, and the expression of α2-adrenergic and M2 muscarinic receptors in the primary visual cortex was determined using immunohistochemistry (IHC).

KEY FINDINGS

The study showed that α2-adrenergic and M2 muscarinic receptors were significantly suppressed in all layers of the primary visual cortex of male neonates born to diabetic rats at P0, P7, and P14 compared to the control group. The highest expression was for the Con group at P14 and the lowest one was in the Dia group at P0 for both receptors. The insulin treatment in diabetic mothers modulated the expression of these receptors to normal levels in their newborns.

SIGNIFICANCE

The results demonstrate maternal diabetes decreases the expression of α2-adrenergic and M2 muscarinic receptors in the primary visual cortex of male offspring born to diabetic rats. Insulin treatment can offset these effects of diabetes.

Early nutritional intake influences the serum levels of nerve growth factor (NGF) and brain-derived neurotrophic factor in preterm newborns

Introduction

Parenteral nutrition (PN) may have detrimental effects on neurodevelopment in preterm newborns. Moreover, enteral nutrition (EN) seems to be protective. To understand the mechanisms of how neurological development can be influenced by the route of administration of nutritional intake, we investigated the relationship between the serum levels of the nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) and nutritional intake received in early life by preterm newborns.

Materials and methods

Specimens of blood were obtained at 28 days of life (DOL) for NGF/BDNF determination in neonates <32 weeks of gestation and/or with birth weight <1,500 g, consecutively observed in the neonatal intensive care unit. We analyzed the relation between amino acid content and energy intake and NGF/BDNF measurements at 28 DOL. PN protein intake was referred to as the total amounts of amino acid intake received daily.

Results

We enrolled 20 newborns (gestational age 30.45 ± 1.76 weeks, birth weight 1,340 ± 352.63 g). Serum NGF value at 28 DOL was positively correlated with enteral protein and energy intake (r = 0.767; r = 0.746, p < 0.001), whereas, negatively correlated with parenteral amino acid and energy intake (r = −0.652, p < 0.001; r = −0.466, p < 0.05). Similar significant correlations were described between BDNF level at 28 DOL and enteral energy intake (r = 0.493, p < 0.05). Multivariate regression analysis showed that NGF level at 28 DOL depends on enteral protein and energy intake administrated in the 1st week of life.

Conclusion

Neurotrophin values varied according to the route of nutrition administration in preterm newborns. NGF/BDNF serum levels are influenced positively and negatively by EN and PN, respectively.

Gestational acrylamide exposure and biomarkers of fetal growth: Probing the mechanism underlying the association between acrylamide and reduced fetal growth

INTRODUCTION

Four epidemiological studies have shown a negative association between prenatal acrylamide exposure and birth size. In order to shed light on the possible underlying mechanism(s), we analysed associations between acrylamide biomarkers and biomarkers related to fetal growth.

METHODS

In newborns of the ENVIRONAGE birth cohort (n ranges from 215 to 434), we investigated the association between prenatal acrylamide exposure (acrylamide and glycidamide hemoglobin adduct levels in cord blood) and thyroid hormones (TSH, T3, T4 and the ratio of T4 to T3 in cord plasma), insulin-related factors (cord plasma insulin and IGF1, and placental IGF2), neurotrophins (cord plasma BDNF, and placental NGF, NT3 and NT4), and cord plasma homocysteine and progesterone, using multiple linear regression analysis. In addition, we investigated whether the biomarkers mediated the associations between prenatal acrylamide exposure and birth outcomes.

RESULTS

We observed lower cord plasma TSH (-10.2% [95% CI: -15.0, -4.3]) and higher placental NGF levels (10.0% [95% CI 3.7, 17.4]) for a twofold increase of acrylamide adducts, a decrease in the ratio of cord plasma free T4 and free T3 with higher acrylamide and glycidamide adducts of -2.9% (95% CI: -5.7, -0.1) and -3.9% (95% CI: -6.2, -1.6) for a twofold increase in acrylamide and glycidamide adduct levels, respectively, and higher cord plasma free T3 with increases in both acrylamide and glycidamide adducts of 2.8% (95% CI: 0.2, 5.6) and 3.6% (95% CI: 0.8, 6.6) for a twofold increase in acrylamide and glycidamide adduct levels, respectively. Additionally, a twofold increase in glycidamide adducts was associated with lower cord plasma insulin levels, particularly among newborns of non-smoking mothers (-11.2% [95% CI: -19.5, -0.1]). Cord plasma insulin seemed to mediate the association between glycidamide adducts and birth weight.

CONCLUSIONS

A decrease in cord plasma insulin levels may be (a marker of) a mechanism by which gestational acrylamide exposure is associated with decreased fetal growth. The possible health consequences of the associations between gestational acrylamide exposure and thyroid hormones and neurotrophins warrant future study.

Neurotrophic Factors in Human Milk in Early Lactation and the Effect of Holder and Microwave Pasteurization on Their Concentrations

OBJECTIVES

The objective of this study was to determine the level of brain-derived neurotrophic factor (BDNF) and glial cell line-derived neurotrophic factor (GDNF) in human milk in the first 2 weeks of breast-feeding and compare the effects of Holder pasteurization (HoP, 62.5 °C, 30 minutes) and microwave pasteurization (MP) at constant temperature (62.5 °C) on the concentraion of both neurotrophic factors (NFs).

METHODS

Concentration of NFs in human milk was determined using a commercially available ELISA assay.

RESULTS

The average concentration of BDNF and GDNF in milk was 11 ± 6 ng/mL and 336 ± 238 pg/mL, respectively. There was a positive correlation between the concentrations of BDNF and GDNF in human milk and day of lactation (r = 0.441, P < 0.05 and r = 0.482, P < 0.05, respectively). In addition, there was a significant correlation between the levels of BDNF and GDNF (r = 0.366, P < 0.05). HoP and MP for 10 minutes affected both NF levels similarly, causing degradation of BDNF by about 24% and 17%, and GDNF by 47% and 45%, respectively. Use of MP for 5 minutes resulted in preservation of nearly 91% BDNF and 79% GDNF in human milk.

CONCLUSIONS

In the pasteurization processes carried out, results showed that GDNF is more susceptible to degradation under the influence of high temperature. To the authors' best knowledge, this is the first study evaluating the effects of HoP and MP at constant temperature on the concentration of NFs in human milk. It was found that the MP for 5 minutes is the optimal method.

Role of neurotrophins in pregnancy and offspring brain development

Neurotrophins are a family of functionally and structurally related proteins which play a key role in the survival, development, and function of neurons in both the central and peripheral nervous systems. Brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF), neurotrophin-3 (NT-3), and neurotrophin-4 (NT-4) are the family members of neurotrophins. Neurotrophins play a crucial role in influencing the development of the brain and learning and memory processes. Studies demonstrate that they also play crucial role in influencing reproductive and immune systems. Neurotrophins have been shown to influence various processes in the mother, placenta, and fetus during pregnancy. Development and maturation of feto-placental unit and the fetal growth trajectories are influenced by neurotrophins. In addition to neurotrophins, neuropeptides like neuropeptide Y also play a crucial role during various processes of pregnancy and during fetal brain development. Neurotrophins have also been shown to have a cross talk with various angiogenic factors and influence placental development. Alterations in the levels of neurotrophins and neuropeptides lead to placental pathologies resulting in various pregnancy complications like preeclampsia, intrauterine growth restriction and preterm births. Studies in animals have reported low levels of maternal micronutrients like folic acid, vitamin B₁₂ and omega-3 fatty acids influence brain neurotrophins resulting in impaired cognitive functioning in the offspring. Maternal nutrition is also known to affect the expression of neuropeptides. It is essential to understand the role of various neurotrophins across various stages of pregnancy and its relationship with neurodevelopmental outcomes in children. This will lead to early prediction of poor neurodevelopmental outcomes. The present review describes evidence describing the role of neurotrophins in determining pregnancy outcome and altered neurodevelopment in the offspring. The possible mechanism through which maternal nutrition influences neurotrophins and neuropeptides to regulate offspring brain development and function is also discussed.

Temporal development of the infant gut microbiome

The majority of organisms that inhabit the human body reside in the gut. Since babies are born with an immature immune system, they depend on a highly synchronized microbial colonization process to ensure the correct microbes are present for optimal immune function and development. In a balanced microbiome, symbiotic and commensal species outcompete pathogens for resources. They also provide a protective barrier against chemical signals and toxic metabolites. In this targeted review we will describe factors that influence the temporal development of the infant microbiome, including the mode of delivery and gestational age at birth, maternal and infant perinatal antibiotic infusions, and feeding method-breastfeeding versus formula feeding. We will close by discussing wider environmental pressures and early intimate contact, particularly between mother and child, as they play a pivotal role in early microbial acquisition and community succession in the infant.