IGF-I and relation to growth in infancy and early childhood in very-low-birth-weight infants and term born infants

Gut development following insulin-like growth factor-1 supplementation to preterm pigs

BACKGROUND

Reduced insulin-like growth factor-1 (IGF-1) levels may contribute to impaired organ development in preterm infants. Using preterm pigs as a model, we hypothesized that IGF-1 supplementation improves health and gut development during the first three weeks of life.

METHODS

First, clinical and organ endpoints were compared between artificially-reared, cesarean-delivered preterm pigs and vaginally-delivered, sow-reared term pigs at 5, 9 and 19 days. Next, preterm pigs were treated with recombinant human IGF-1 for 19 days (2.25 mg/kg/day, systemically).

RESULTS

Relative to term pigs, preterm pigs had lower body weight, fat, bone contents, relative weights of liver and spleen and a longer and thinner intestine at 19 days. Preterm birth reduced intestinal villi heights and peptidase activities, but only at 5 and 9 days. In preterm pigs, IGF-1 reduced mortality primarily occurring from gastrointestinal complications and with a tendency towards salvaging smaller pigs. IGF-1 supplementation also increased spleen and kidney weights, small intestine length and maltase to lactase activity, reflecting gut maturation.

CONCLUSION

Preterm birth affects body composition and gut maturation in the first 1-2 weeks, but differences are marginal thereafter. Supplemental IGF-1 may improve gut health in pigs and infants in the first few weeks after preterm birth.

IMPACT

Insulin-like growth factor 1 (IGF-1) supplementation may improve gut health and development in prematurity, but whether the effects are sustained beyond the immediate postnatal period is unclear. In preterm pigs, the prematurity effects on IGF-1 and gut health deficiencies are most pronounced during the first week of life and diminishes thereafter. In preterm pigs, IGF-1 supplementation beyond the first week of life reduced mortality. The present study provides evidence of a sustained effect of IGF-1 supplementation on the gastrointestinal tract after the immediate postnatal period.

Glucose-regulatory hormones and growth in very preterm infants fed fortified human milk

BACKGROUND

Bovine colostrum (BC) contains a range of milk bioactive components, and it is unknown how human milk fortification with BC affects glucose-regulatory hormones in very preterm infants (VPIs). This study aimed to investigate the associations between hormone concentrations and fortification type, birth weight (appropriate/small for gestational age, AGA/SGA), milk intake, postnatal age, and body growth.

METHODS

225 VPIs were randomized to fortification with BC or conventional fortifier (CF). Plasma hormones were measured before, one and two weeks after start of fortification. ΔZ-scores from birth to 35 weeks postmenstrual age were calculated.

RESULTS

Compared with CF, infants fortified with BC had higher plasma GLP-1, GIP, glucagon, and leptin concentrations after start of fortification. Prior to fortification, leptin concentrations were negatively associated with growth, while IGF-1 concentrations associated positively with growth during fortification. In AGA infants, hormone concentrations generally increased after one week of fortification. Relative to AGA infants, SGA infants showed reduced IGF-1 and leptin concentrations.

CONCLUSION

Fortification with BC increased the plasma concentrations of several glucose-regulatory hormones. Concentrations of IGF-1 were positively, and leptin negatively, associated with growth. Glucose-regulatory hormone levels were affected by birth weight, milk intake and postnatal age, but not closely associated with growth in VPIs.

IMPACT

Little is known about the variation in glucose-regulatory hormones in the early life of very preterm infants (VPIs). This study shows that the levels of glucose-regulatory hormones in plasma of VPIs are highly variable and modified by birth weight (appropriate or small for gestational age, AGA or SGA), the type of fortifier, enteral nutritional intake, and advancing postnatal age. The results confirm that IGF-1 levels are positively associated with early postnatal growth in VPIs, yet the levels of both IGF-1 and other glucose-regulatory hormones appeared to explain only a small part of the overall variation in growth rates.

Insulin-like growth factor-1 and insulin-like growth factor binding protein-3 as early predictors of growth, body composition, and neurodevelopment in preterm infants

OBJECTIVE

To investigate the relationship between insulin-like growth factor 1 (IGF-1), insulin-like growth factor binding protein 3 (IGFBP-3) and long-term growth, body composition, and neurodevelopment in preterm infants.

STUDY DESIGN

Prospective data were collected from ≤32 weeks gestational age infant cohort (N = 50). IGF-1 and IGFBP-3 concentrations were measured at 1 week (early) and 35 weeks (late) post-menstrual age (PMA). Growth, body composition, and neurodevelopment outcomes were measured at 4 and 12 months PMA. Relationships were measured by linear regression analysis.

RESULTS

Early IGFBP-3 concentration was positively associated with neurodevelopment at 12 months PMA. Early IGF-1 concentration was positively associated with weight at 4 months PMA, head circumference at 12 months PMA, and body mass index at 12 months PMA. Late IGFBP-3 concentration was positively associated with weight at 4 months PMA.

CONCLUSION

Further investigation of these associations may lead to novel biomarkers and/or treatments to optimize health outcomes in preterm infants.

Correlations of Aflatoxin Exposure from Cooking Oil and Dietary Foods During Pregnancy with Birth Weight and Gestational Age at Birth in Guangxi, China

Background

Cooking oil and dietary foods are easily contaminated by aflatoxins (AFs) in Guangxi, China where low birth weight and preterm birth were prevalent. However, there are no data on AF exposure in pregnant women or their impact on newborn birth outcomes. This study aims to measure the levels and correlations of AFs in cooking oil, estimated dietary intake (EDI) of AFs in dietary foods, and serum AFB1 albumin adducts (AFB1-alb) with newborn birthweight and gestational age at birth.

Methods

A prospective study was conducted among 126 pregnant women in Guangxi, China. All recruited women were interviewed for demographic data and behavior and obstetric information and then followed up until giving birth. AF measurements were obtained from cooking oil, dietary foods, maternal serum, and cord blood and the correlations of AF levels with newborn birthweight and gestational age at birth were tested using correlation analysis.

Results

The median EDI of AFs in cooking oil was 2.61 ng/kg.bw/day and in dietary foods 2.95 ng/kg.bw/day. High positive correlations among EDI of aflatoxin B1 (AFB1) from cooking oil and dietary foods were found (r > 0.7). Low positive correlations of AFB1-alb in maternal serum and cord blood and both EDI of AFB1 in both cooking oil and dietary foods were shown (r ≈0.3). Significant correlations between AF levels in both cooking oil and dietary foods with birth weight were found, but very low negative correlations (r = - 0.244 ~ -0.285). AFB1 levels in foods, maternal serum and cord blood levels were high in pregnant women with newborn low birth weight and preterm birth.

Conclusion

The EDIs of AFB1 from both cooking oil and dietary foods were significantly correlated with AFB1-alb in maternal serum and cord blood. Negative correlations of AFs from cooking oils and foods with newborn birth weight should be paid more attention.

Growth Factor Independence-1 (GFI-1) Gene Expression in Hematopoietic Stem Cell Lineage Differentiation in Low Birth Weight Newborns Compared With Normal Birth Weight Newborns at Term Pregnancy

Introduction Low birth weight (LBW), which is a risk factor for noncommunicable diseases throughout life, is a significant public health concern. In addition to regulating myeloid cell differentiation and proliferation, a transcriptional repressor identified as growth factor independence-1 (GFI-1) is essential for hematopoietic stem cell maintenance and self-renewal. The current study was designed to compare the expression of the GFI-1 gene in the differentiation of hematopoietic stem cells in newborns with LBW and those with normal birth weight (NBW). Methods A prospective comparative analytical study was carried out from September 2019 to September 2021 after obtaining Institute Ethical Committee approval at a tertiary care center in north India. The GFI-1 gene expression levels in 50 cord blood samples from women with term gestation and LBW newborns (<2500 grams) were measured using quantitative real-time polymerase chain reaction (RT-PCR) and compared to gene expression levels in 50 cord blood samples from women with term gestation and NBW newborns (≥2500 grams). The data were analyzed using IBM SPSS statistics software version 24.0 (IBM Corp., Armonk, NY). Results The median GFI-1 expression in LBW newborns is 3.1, whereas among NBW newborns it is 9.39. The difference is significant (P <0.001). The level of GFI-1 gene expression in LBW newborns was correlated with their birth weight. The coefficient of correlation was found to be weakly positive (r = 0.223). The birth weight of NBW newborns was correlated to the level of expression of the GFI-1 gene, which was found to be positively correlated (r = 0.332). Conclusion The levels of the GFI-1 gene and newborn birth weight were compared in LBW infants, which were weakly positively correlated. The level of GFI-1 gene expression at birth was compared to the birth weight of NBW newborns, which was positively correlated.

Neighborhood Social Vulnerability and Interstage Weight Gain: Evaluating the Role of a Home Monitoring Program

Background Poor interstage weight gain is a risk factor for adverse outcomes in infants with hypoplastic left heart syndrome. We sought to examine the association of neighborhood social vulnerability and interstage weight gain and determine if this association is modified by enrollment in our institution's Infant Single Ventricle Management and Monitoring Program (ISVMP). Methods and Results We performed a retrospective single-center study of infants with hypoplastic left heart syndrome before (2007-2010) and after (2011-2020) introduction of the ISVMP. The primary outcome was interstage weight gain, and the secondary outcome was interstage growth failure. Multivariable linear and logistic regression models were used to examine the association between the Social Vulnerability Index and the outcomes. We introduced an interaction term into the models to test for effect modification by the ISVMP. We evaluated 217 ISVMP infants and 111 pre-ISVMP historical controls. The Social Vulnerability Index was associated with interstage growth failure (P=0.001); however, enrollment in the ISVMP strongly attenuated this association (P=0.04). Pre-ISVMP, as well as high- and middle-vulnerability infants gained 4 g/d less and were significantly more likely to experience growth failure than low-vulnerability infants (high versus low: adjusted odds ratio [aOR], 12.5 [95% CI, 2.5-62.2]; middle versus low: aOR, 7.8 [95% CI, 2.0-31.2]). After the introduction of the ISVMP, outcomes did not differ by Social Vulnerability Index tertile. Infants with middle and high Social Vulnerability Index scores who were enrolled in the ISVMP gained 4 g/d and 2 g/d more, respectively, than pre-ISVMP controls. Conclusions In infants with hypoplastic left heart syndrome, high social vulnerability is a risk factor for poor interstage weight gain. However, enrollment in the ISVMP significantly reduces growth disparities.

Correction of neonatal vitamin D status using 1000 IU vitamin D/d increased lean body mass by 12 months of age compared with 400 IU/d: a randomized controlled trial

BACKGROUND

Intrauterine exposure to maternal vitamin D status <50 nmol/L of serum 25-hydroxyvitamin D [25(OH)D] may adversely affect infant body composition. Whether postnatal interventions can reprogram for a leaner body phenotype is unknown.

OBJECTIVES

The primary objective was to test whether 1000 IU/d of supplemental vitamin D (compared with 400 IU/d) improves lean mass in infants born with serum 25(OH)D <50 nmol/L.

METHODS

Healthy, term, breastfed infants (Montréal, Canada, March 2016-2019) were assessed for serum 25(OH)D (immunoassay) 24-36 h postpartum. Infants with serum 25(OH)D <50nmol/L at 24-36 h were eligible for the trial and randomly assigned at baseline (1 mo postpartum) to 400 (29 males, 20 females) or 1000 IU/d (29 males, 20 females) of vitamin D until 12 mo. Infants (23 males, 18 females) with 25(OH)D ≥50 nmol/L (sufficient) formed a nonrandomized reference group provided 400 IU/d. Anthropometry, body composition (DXA), and serum 25(OH)D concentrations were measured at 1, 3, 6, and 12 mo.

RESULTS

At baseline, mean ± SD serum 25(OH)D concentrations in infants allocated to the 400 and 1000 IU/d vitamin D groups were 45.8 ± 14.1 and 47.6 ± 13.4, respectively; for the reference group it was 69.2 ± 16.4 nmol/L. Serum 25(OH)D concentration increased on average to ≥50 nmol/L in the trial groups at 3-12 mo. Lean mass varied differently between groups over time; at 12 mo it was higher in the 1000 IU/d vitamin D group than in the 400 IU/d group (mean ± SD: 7013 ± 904.6 compared with 6690.4 ± 1121.7 g, P = 0.0428), but not the reference group (mean ± SD: 6715.1 ± 784.6 g, P = 0.19). Whole-body fat mass was not different between the groups over time.

CONCLUSIONS

Vitamin D supplementation (400 or 1000 IU/d) during infancy readily corrects vitamin D status, whereas 1000 IU/d modestly increases lean mass by 12 mo. The long-term implications require further research. This trial was registered at clinicaltrials.gov as NCT02563015.

Relationship Between Serum Brain-Type Natriuretic Peptide and Biomarkers of Growth in Infants With Shunt-Dependent Single Cardiac Ventricle

For infants with shunt-dependent or ductal-dependent single ventricle heart disease, poor growth is common and associated with morbidity and impaired neurodevelopmental outcomes. Although attention has focused on nutrition to promote weight gain, little is known about the relation between heart failure and growth factors. A prospective observational pilot study was performed to assess the relation between heart failure, assessed by brain natriuretic peptide (BNP), and growth factors (insulin-like growth factor 1 [IGF-1] and insulin-like growth factor-binding protein 3) at 3 visits: (1) before discharge from neonatal intervention with the establishment of stable pulmonary blood flow, (2) immediately before superior cavopulmonary connection, and (3) before discharge after superior cavopulmonary connection operation. The relation between BNP and growth factors was analyzed using Spearman pairwise correlations at each visit and modeled over time with a linear mixed-effects model. Correlations were considered worthy of further exploration using a p <0.10, given the exploratory nature of the study. The study included 38 infants (66% male, 68% hypoplastic left heart syndrome). Median BNP was elevated at visit 1 and decreased over time (287 pg/dl [interquartile range 147 to 794], 85 pg/dl [52 to 183], and 90 pg/dl [70 to 138]). Median IGF-1 Z score was <0 at each visit but increased over time (-0.9 [interquartile range -1.1 to 0.1], -0.7 [-1.2 to 0.1], and -0.5 [-1.2 to 0]). Inverse correlations were found between BNP and IGF-1 at visit 1 (r = -0.40, p = 0.097), BNP and IGF-1 and insulin-like growth factor-binding protein 3 at visit 2 (r = -0.33, p = 0.080 and r = -0.33, p = 0.085, respectively) and BNP and IGF-1 Z score at visit 3 (r = -0.42, p = 0.049). Significant relations were likewise found between the change in BNP and the change in IGF-1 between visits 1 and 3 (p = 0.046) and between visits 2 and 3 (p = 0.048). In conclusion, this pilot study demonstrates an inverse correlation between BNP and growth factors, suggesting that the heart failure state associated with this physiology may play a mechanistic role in impaired growth.

Clinical outcome and gut development after insulin-like growth factor-1 supplementation to preterm pigs

BACKGROUND

Elevation of circulating insulin-like growth factor-1 (IGF-1) within normal physiological levels may alleviate several morbidities in preterm infants but safety and efficacy remain unclear. We hypothesized that IGF-1 supplementation during the first 1-2 weeks after preterm birth improves clinical outcomes and gut development, using preterm pigs as a model for infants.

METHODS

Preterm pigs were given vehicle or recombinant human IGF-1/binding protein-3 (rhIGF-1, 2.25 mg/kg/d) by subcutaneous injections for 8 days (Experiment 1, n = 34), or by systemic infusion for 4 days (Experiment 2, n = 19), before collection of blood and organs for analyses.

RESULTS

In both experiments, rhIGF-1 treatment increased plasma IGF-1 levels 3-4 fold, reaching the values reported for term suckling piglets. In Experiment 1, rhIGF-1 treatment increased spleen and intestinal weights without affecting clinical outcomes like growth, blood biochemistry (except increased sodium and gamma-glutamyltransferase levels), hematology (e.g., red and white blood cell populations), glucose homeostasis (e.g., basal and glucose-stimulated insulin and glucose levels) or systemic immunity variables (e.g., T cell subsets, neutrophil phagocytosis, LPS stimulation, bacterial translocation to bone marrow). The rhIGF-1 treatment increased gut protein synthesis (+11%, p < 0.05) and reduced the combined incidence of all-cause mortality and severe necrotizing enterocolitis (NEC, p < 0.05), but had limited effects on intestinal morphology, cell proliferation, cell apoptosis, brush-border enzyme activities, permeability and levels of cytokines (IL-1β, IL-6, IL-8). In Experiment 2, rhIGF-1 treated pigs had reduced blood creatine kinase, creatinine, potassium and aspartate aminotransferase levels, with no effects on organ weights (except increased spleen weight), blood chemistry values, clinical variables or NEC.

CONCLUSION

Physiological elevation of systemic IGF-1 levels for 8 days after preterm birth increased intestinal weight and protein synthesis, spleen weight and potential overall viability of pigs, without any apparent negative effects on recorded clinical parameters. The results add further preclinical support for safety and efficacy of supplemental IGF-1 to hospitalized very preterm infants.

Dynamic Changes in Serum IGF-I and Growth During Infancy: Associations to Body Fat, Target Height, and PAPPA2 Genotype

CONTEXT

IGF-I is important for postnatal growth and may be of diagnostic value in infants suspected of pituitary disease; however, little is known about the impact of IGF-I and its determinants on infant growth. Importantly, detailed reference ranges for IGF-I and IGF binding protein-3 (IGFBP-3) concentrations during infancy are lacking.

OBJECTIVE

To evaluate the rapid changes in weight and length as well as their determinants in healthy infants, and to establish age- and sex-specific reference curves for IGF-I and IGFBP-3 in children aged 0 to 1 years.

DESIGN

Prospective longitudinal study.

SETTING

Cohort study.

PARTICIPANTS

A total of 233 healthy children (114 girls) with repeated blood samples during the first year of life.

MAIN OUTCOME MEASURE(S)

Serum concentrations of IGF-I and IGFBP-3, length velocity, weight velocity, and PAPPA2 (rs1325598) genotype.

RESULTS

Individual trajectories of length and weight velocities were sex specific. We provide detailed reference curves based on longitudinal data for IGF-I and IGFBP-3 during infancy. In both girls and boys, IGF-I decreased during infancy, whereas IGFBP-3 remained stable. IGF-I and IGFBP-3, but not PAPPA2 genotype, were positively associated with weight gain, but not with longitudinal growth. When stratified by sex, the association between weight gain and IGF-I only remained significant in girls.

CONCLUSIONS

Interestingly, we found a significant association between IGF-I and infant weight gain in girls, but not with longitudinal growth in the first year of life. Our findings highlight the role of IGF-I as an important anabolic hormone that is not limited to linear growth.

Cortisol and Cortisone in Early Childhood in Very-Low-Birthweight Infants and Term-Born Infants

INTRODUCTION

Besides programming of the hypothalamic-pituitary-adrenal (HPA) axis, changes in the activity of 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2) could contribute to the later metabolic and cardiovascular consequences of preterm birth.

OBJECTIVE

We compared serum cortisol, cortisone, and cortisol/cortisone ratio in early childhood in very-low-birthweight (VLBW) infants and term appropriate for gestational age (AGA) born infants.

METHODS

We included 41 VLBW infants, participating in the randomized controlled Neonatal Insulin Replacement Therapy in Europe trial, and 64 term AGA-born infants. Cortisol and cortisone were measured in blood samples taken at 6 months and 2 years corrected age (VLBW children) and at 3 months and 1 and 2 years (term children). At 2 years of (corrected) age (HDL) cholesterol, triglycerides, glucose, and insulin were also measured.

RESULTS

During the first 2 years of life, cortisol/cortisone ratio is higher in VLBW children compared to term children. In the total group of children, cortisol/cortisone ratio is positively related to triglycerides at 2 years of (corrected) age. In VLBW children, over the first 2 years of life both cortisol and cortisone are higher in the early-insulin group compared to the standard care group.

CONCLUSIONS

In VLBW infants, lower 11β-HSD2 activity probably contributes to the long-term metabolic and cardiovascular risks. In VLBW infants, early insulin treatment could affect programming of the HPA axis, resulting in higher cortisol and cortisone levels during early childhood.

An integrated approach to identify environmental modulators of genetic risk factors for complex traits

Complex traits and diseases can be influenced by both genetics and environment. However, given the large number of environmental stimuli and power challenges for gene-by-environment testing, it remains a critical challenge to identify and prioritize specific disease-relevant environmental exposures. We propose a framework for leveraging signals from transcriptional responses to environmental perturbations to identify disease-relevant perturbations that can modulate genetic risk for complex traits and inform the functions of genetic variants associated with complex traits. We perturbed human skeletal-muscle-, fat-, and liver-relevant cell lines with 21 perturbations affecting insulin resistance, glucose homeostasis, and metabolic regulation in humans and identified thousands of environmentally responsive genes. By combining these data with GWASs from 31 distinct polygenic traits, we show that the heritability of multiple traits is enriched in regions surrounding genes responsive to specific perturbations and, further, that environmentally responsive genes are enriched for associations with specific diseases and phenotypes from the GWAS Catalog. Overall, we demonstrate the advantages of large-scale characterization of transcriptional changes in diversely stimulated and pathologically relevant cells to identify disease-relevant perturbations.

Infant eating behaviors and Milk feeding independently predict infant size

OBJECTIVES

This study investigates the association of infant eating behaviors with infant size, and if those associations are mediated by infant feeding.

METHODS

Mothers with infants less than 12 months of age and living in Central North Carolina were enrolled (N = 61). Data were collected at baseline and at 3- and 6-month follow up visits. Modified constructs from the Baby Eating Behavior Questionnaire (BEBQ) and Child Eating Behavior Questionnaire (CEBQ) measured parents' perceptions of infant eating behaviors related to food approach (enjoyment of food, and food responsiveness) and food avoidance (food fussiness, satiety responsiveness, and slowness in eating). Linear mixed effects models tested longitudinal associations among infant eating behavior ratings, infant feeding (breastfeeding intensity, timing of introduction of complementary foods), and anthropometry (weight, length, and weight-for-length z-scores). Path analyses were stratified by age and tested for direct and indirect effects of mothers' ratings of infant eating behaviors and infant feeding on infant anthropometry.

RESULTS

Linear mixed models showed that general appetite was associated with higher weight-for-age, and satiety responsiveness was associated with lower length-for-age. Path analyses showed that infant milk feeding did not mediate associations. Breastfeeding intensity was independently associated with lower weight- and length-for-age z-scores. Age at complementary feeding initiation was associated with lower length-for-age z-scores.

CONCLUSIONS

Associations between parental perceptions of general appetite, satiety responsiveness, and infant weight and length are observed early in life. These findings suggest that parental perceptions of infant eating behaviors may contribute to the early developmental programming of later health outcomes.

Human milk composition promotes optimal infant growth, development and health

Human milk is a living dynamic fluid that promotes optimal nutrition and development of the infant and impacts health across the lifespan. This review reports on the diverse range of nutrients, immune protection factors, hormones, microbes and metabolites in human milk and their impacts on infant nutrition and health. While many of these components are stable across lactation and similar between women, some vary over time, and in response to maternal and infant health status, maternal diet and geographic location. Human milk may be considered as personalized nutrition, with many components working synergistically to stimulate and support the infant's immature immune system, while enhancing appropriate development, growth and body composition.

RELATIONSHIP BETWEEN INSULIN-LIKE GROWTH FACTOR TYPE 1 AND INTRAUTERINE GROWTH

Insulin-like growth factor 1 (IGF-1) is a regulator of intrauterine growth, and circulating concentrations are reduced in intrauterine growth-restricted fetuses. The aim of our study was to investigate the relationship between IGF-1 levels in newborns and intrauterine growth, expressed as birth weight (BW). The research was designed as a cross-sectional study. The study included 71 premature newborns, gestational age (GA) ≤33 weeks. Quantitative determination of IGF-1 was performed in the 33^rd post-menstrual week (pmw) to make the measurements more comparable. We used an enzyme-bound immunosorbent test for quantitative determination of IGF-1. Our results showed the mean IGF-1 level in premature newborns in 33^rd pmw to be 23.1±4.56 (range 15.44-39.75) µg/L. There was no difference in IGF-1 values between male (23.1±4.98 µg/L) and female (23.1±4.87 µg/L) newborns. There was no significant difference in the average IGF-1 levels between male and female newborns with BW <50^th and BW >50^th percentile for GA either (p>0.50). Only BW <33^rd percentile newborns had a statistically significantly lower IGF-1 level compared to newborns with greater BW. Based on our results, it is concluded that serum IGF-1 level reflects intrauterine growth only in BW <33^rd percentile newborns. This fact could be used for further therapeutic purposes.

Insulin-Like Growth Factor-1 Is Neuroprotective in Aged Rats With Ischemic Stroke

Post-stroke systemic injections of insulin-like growth factor-1 (IGF-1) exert neuroprotective effects in rats. In the current study, we aimed to test the efficacy of IGF-1 neuroprotection in aged rats (24–25 months old) and to compare the results with adult rats (6–7 months old). Furthermore, we addressed putative differences in microglial responses to IGF-1 in adult and aged rats. Rats were subjected to ischemic stroke while they were conscious by infusing endothelin-1 (Et-1) through a guide cannula that was implemented in the vicinity of the middle cerebral artery (MCA). Rats were given subcutaneous injections of IGF-1 (1 mg/kg) at 30 min and 120 min after the insult. Post-stroke IGF-1 treatment reduced the infarct size by 34% and 38% in aged and adult rats, respectively. The IGF-1 treated adult rats also showed significant improvement in sensorimotor function following stroke, while this function was not significantly affected in aged rats. Furthermore, aged rats displayed exaggerated activation of microglia in the ischemic hemisphere. Significant reduction of microglial activation by IGF-1 was only detected at specific regions in the ipsilateral hemisphere of adult rats. We show that IGF-1 reduced infarct size in aged rats with an ischemic stroke. It remains to be established, however, whether the age-related changes in microglial function affect the improvement in behavioral outcomes.

Maternal protein intake during pregnancy is associated with child growth up to 5 years of age, but not through insulin-like growth factor-1: findings from the ROLO study

Infant protein intake has been associated with child growth, however, research on maternal protein intake during pregnancy is limited. Insulin-like growth factors (IGF) play a role in early fetal development and maternal protein intake may influence child body composition via IGF-1. The aim of this study was to investigate the association of maternal protein intake throughout pregnancy on cord blood IGF-1 and child body composition from birth to 5 years of age. Analysis was carried out on 570 mother-child dyads from the Randomised cOntrol trial of LOw glycaemic index diet study. Protein intake was recorded using 3-d food diaries in each trimester of pregnancy and protein intake per kg of maternal weight (g/d per kg) was calculated. Cord blood IGF-1 was measured at birth. Infant anthropometry was measured at birth, 6 months, 2 and 5 years of age. Mixed modelling, linear regression, and mediation analysis were carried out. Birth weight centiles were positively associated with early-pregnancy protein intake (g/d per kg), while weight centiles from 6 months to 5 years were negatively associated (B=-21·6, P<0·05). These associations were not mediated by IGF-1. Our findings suggest that high protein intake in early-pregnancy may exert an in utero effect on offspring body composition with a higher weight initially at birth but slower growth rates into childhood. Further research is needed to elucidate the exact mechanisms by which dietary protein modulates fetal growth.

Hormones in Breast Milk and Effect on Infants' Growth: A Systematic Review

Breast milk is characterized by a dynamic and complex composition which includes hormones and other bioactive components that could influence infant growth, development, and optimize health. Among the several beneficial effects associated with prolonged breastfeeding, a 13% decrease in the risk of overweight and obesity has been reported. Recent research has focused on breast milk hormones contributing to the appetite and energy balance regulation and adiposity. Accordingly, we conducted a literature systematic review with the aim to provide an update on the effect of leptin, ghrelin, Insulin Growth Factor 1, adiponectin, and insulin on infants' and children's growth and body composition. The revised literature reveals contrasting findings concerning the potential role of all these hormones on modeling growth and fat mass apposition and health outcomes later in life. Further studies are needed to gain further insight into the specific role of these bioactive components in metabolic pathways related to body composition. This could help gain a further insight on infants' growth, both in physiological and pathological settings.

Effect of Early Breast Milk Nutrition on Serum Insulin-Like Growth Factor-1 in Preterm Infants

BACKGROUND:

Insulin-like growth factor 1 (IGF-1) is one of the essential intrauterine hormonal mediators of growth, and its serum values are often low after preterm delivery.

AIM:

To evaluate the influence of immediate breast milk feeding on serum IGF-1 in preterm newborns.

SUBJECTS AND METHODS:

This prospective, observational cohort study included 60 premature infants born < 32 weeks of gestation, divided into group A and B regarding breastfeeding or formula feeding. Growth measurements were taken at birth. The standard deviation of each measurement was calculated. Serum IGF-I was measured one day postnatal and at a time equivalent to 40 weeks of gestation.

RESULTS:

Significant higher level of mean serum IGF-1 was detected in group A than B at postnatal age equivalent to 40 weeks of gestation. In group A, the higher significant level was detected in mean serum IGF-1 at an age equivalent to 40 weeks of gestation than at birth (25.21 ± 6.69 and 20.13 ± 5.46 p < 0.05). Multiple linear regression analysis showed that high birth weight, increased age of gestation and breastfeeding were correlated to the elevated serum level of IGF-1 at a postnatal age corresponding to 40 weeks gestational age.

CONCLUSION:

Immediate breast milk feeding was accompanied by elevated IGF-1 in the serum of preterm infants.