Effects of cord serum insulin, IGF-II, IGFBP-2, IL-6 and cortisol concentrations on human birth weight and length: pilot study

Hormonal Determinants of Growth and Weight Gain in the Human Fetus and Preterm Infant

The factors controlling linear growth and weight gain in the human fetus and newborn infant are poorly understood. We review here the changes in linear growth, weight gain, lean body mass, and fat mass during mid- and late gestation and the early postnatal period in the context of changes in the secretion and action of maternal, placental, fetal, and neonatal hormones, growth factors, and adipocytokines. We assess the effects of hormonal determinants on placental nutrient delivery and the impact of preterm delivery on hormone expression and postnatal growth and metabolic function. We then discuss the effects of various maternal disorders and nutritional and pharmacologic interventions on fetal and perinatal hormone and growth factor production, growth, and fat deposition and consider important unresolved questions in the field.

Overexpression of IGF2 affects mouse weight and glycolipid metabolism and IGF2 is positively related to macrosomia

Objective

To investigate the effects of insulin-like growth factor 2 (IGF2) on growth and glycolipid metabolism, as well as the underlying mechanism.

Methods

A mouse model of IGF2 overexpression was constructed to measure weight gain before adulthood, to obtain the values of adult glycolipid metabolism indicators in the peripheral blood and to detect the expression of genes in the IGF2 signaling pathway in different mouse tissues. The present study also explored the independent association between the IGF2 gene and macrosomia by detecting and comparing the expression levels of IGF2 mRNA/H19 RNA in maternal peripheral blood and fetal cord blood of 26 human pregnancies.

Results

In the mouse model, weights of the IGF2-overexpressing mice were significantly higher than those of the control mice at the age of 5-10 weeks. The glucose concentration, total cholesterol and high-density lipoprotein cholesterol (HDL-C) levels of IGF2-overexpressing mice were significantly lower than those of wild-type (WT) mice. Compared with the WT mice, the expression of H19 was significantly decreased in the pancreas and IGF1R was significantly decreased in the muscle of mice with IGF2 overexpression. The expression levels of STAT3 and AKT2 showed significant decrease in liver, muscle and increase in muscle of IGF2-overexpressing mice, respectively. GLUT2 expression showed significant increase in liver, kidney, muscle and decrease in pancreas of mice with IGF2 overexpression. This study also found that in normal mothers with the similar clinical characteristics, IGF2 expression in the maternal peripheral blood and fetal cord blood is an independent factor influencing macrosomia.

Conclusion

IGF2 expression was independently correlated with the occurrence of macrosomia, and overexpression of IGF2 significantly increased the weights of mice at the age of 5-10 weeks and significantly affected the values of adult glycolipid metabolism indicators, which might be the result of changes in the IGF2-IGF1R-STAT3/AKT2-GLUT2/GLUT4 pathway. These findings might suggest that IGF2 plays an important role in growth and glycolipid metabolism during both pregnancy and postnatal development.

Identification of miRNAs Involved in Foetal Growth Restriction Due to Maternal Smoking during Pregnancy

INTRODUCTION

Smoking during pregnancy is associated with reduced foetal growth, amongst other effects. Epigenetic modification in the foetus and placenta during embryonic development as a result of changes in the function of miRNAs is one of the pathophysiological mechanisms responsible for this. This dysregulation may be due to environmental changes or toxins such as tobacco.

OBJECTIVE

To study the impact of smoking during pregnancy and its role in intrauterine growth restriction via hypermethylated miRNAs.

MATERIALS AND METHODS

The differences in methylation patterns for miRNAs in umbilical cord blood from low-birth-weight newborns of smoking mothers were compared with those from normal-weight newborns using MedIP-seq (StarArray).

RESULTS

Seven hypermethylated miRNAs were identified in the epigenetic study of cord blood from low-birth-weight newborns of smoking mothers in our sample. The miRNAs found to be hypermethylated were: MIR7-1, MIR3918, MIR1244-1, MIR4721, MIR25, MIR93, MIR3656.

CONCLUSION

Intrauterine exposure to tobacco induces hypermethylation-mediated miRNA silencing in low-birth-weight newborns by modifying the expression of factors involved in vascular development, growth, and adaptation to hypoxia.

Maternal Proinflammatory Adipokines Throughout Pregnancy and Neonatal Size and Body Composition: A Prospective Study

BACKGROUND

Increased maternal adiposity and inflammation have impacts on fetal growth.

OBJECTIVES

The purpose of this prospective study was to investigate the associations of 3 proinflammatory adipokines in pregnancy with neonatal anthropometry.

METHODS

In a sample of 321 US pregnant women from the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) Fetal Growth Studies-Singleton Cohort (NCT00912132), plasma IL-6, fatty acid binding protein-4 (FABP4), and chemerin were measured in plasma samples collected at 10-14, 15-26, 23-31, and 33-39 weeks of gestation. Generalized linear models were used to estimate associations of adipokines with neonatal weight, thigh, and crown-heel length, and skinfolds at birth. Models adjusted for age, race/ethnicity, education, nulliparity, prepregnancy BMI, and weeks of gestation at blood collection.

RESULTS

At each time point, higher IL-6 was associated with lower neonatal birthweight and thigh length. At 15-26 weeks of gestation, a 1 SD pg/mL increase in IL-6 was associated with -84.46 g lower neonatal birthweight (95% CI: -150.70, -18.22), -0.17 cm shorter thigh length (95% CI: -0.27, -0.07), -0.43 cm shorter crown-heel length (95% CI: -0.75, -0.10), and -0.75 mm smaller sum of skinfolds (95% CI: -1.19, -0.31), with similar associations at 23-31 and 33-39 weeks of gestation. There were no associations of FABP4 and chemerin with neonatal anthropometry.

CONCLUSIONS

Starting as early as 15 weeks of gestation, higher maternal IL-6 concentrations in pregnancy were associated with lower neonatal birthweight, thigh and crown-heel length, and skinfolds. These data provide insight into the relevance of maternal inflammatory markers with neonatal anthropometry.

Regulation of Melanophilin (Mlph) gene expression by the glucocorticoid receptor (GR)

Mlph plays a crucial role in regulating skin pigmentation through the melanosome transport process. Although Mlph is a major component involved in melanosome transport, the mechanism that regulates the expression of the Mlph gene has not been identified. In this study, we demonstrate that Mlph expression is regulated by the glucocorticoid receptor (GR). Alteration of GR activity using a specific GR agonist or antagonist only regulated the expression of Mlph among the 3 key melanosome transport proteins. Translocation of GR from the cytosol into the nucleus following Dex treatment was confirmed by separating the cytosol and nuclear fractions and by immunofluorescence staining. In ChIP assays, Dex induced GR binding to the Mlph promoter and we determined that Dex induced the GR binding motif on the Mlph promoter. Our findings contribute to understanding the regulation of Mlph expression and to the novel role of GR in Mlph gene expression.

Associations between Maternal and Fetal Levels of Total Adiponectin, High Molecular Weight Adiponectin, Selected Somatomedins, and Birth Weight of Infants of Smoking and Non-Smoking Mothers

The aim of the study was to determine the relationships between maternal smoking, total adiponectin, high molecular weight adiponectin (HMW adiponectin), selected somatomedins, and the birth weight of newborns. A total of 78 women with a healthy, singleton pregnancy, 41 active smokers and 37 non-smokers, and their offspring were studied. Total and HMW adiponectin, insulin-like growth factor I (IGF-I), and insulin-like growth factor binding protein-1 (IGFBP-1) and 2 (IGFBP-2) were determined in maternal and cord blood by enzyme-link immunosorbent assay. Serum levels of total and HMW adiponectin were lower in smokers compared to the tobacco abstinent in both the mothers (p = 0.013; p = 0.006) and the infants (p = 0.001; p = 0.047). In smoking women and their children, serum concentrations of IGF-I were significantly lower (p = 0.014; p = 0.042), IGFBP-1 significantly higher (p = 0.009; p = 0.039), and IGFBP-2 did not differ from that observed in the non-smoking group. In multivariate analysis performed on the whole group of mothers, the highest impact of serum cotinine and IGFBP-2 levels were indicated for adiponectin and cotinine and the number of cigarettes/day for HMW adiponectin concentration. In correlation analysis estimated separately for smokers and non-smokers, neonatal birth weight was positively associated with total and HMW adiponectin concentrations in umbilical cord blood. Birth weight was also inversely associated with IGFBP-1 and positively correlated with IGF-I levels in maternal serum as well as in cord blood (r = −0.317, p = 0.005; r = −0.294, p = 0.004; r = 0.245, p = 0.031; r = 0.271, p = 0.009, respectively). The present study showed the levels of total and HMW adiponectin in umbilical cord blood may have a significant effect on fetal development. Both IGF-I and IGFBP-1 concentrations also play an essential role in fetal growth, which is an important predictor of birth weight. Cigarette smoking during pregnancy negatively affected adiponectin and the insulin growth factor profile in the serum of women and the cord blood and may be the reason for the lower birth weight of the smokers newborns compared with the nonsmokers offspring.

Endocrine-Disrupting Chemicals in Human Fetal Growth

Fetal growth is regulated by a complex interaction of maternal, placental, and fetal factors. The effects and outcomes that chemicals, widely distributed in the environment, may have on the health status of both the mother and the fetus are not yet well defined. Mainly mixtures of chemical substances are found in the mothers and placenta. Exposure to endocrine-disrupting chemicals (EDCs) can be associated with fetal growth retardation, thyroid dysfunction, and neurological disorders. EDCs mostly interfere with insulin, glucocorticoid, estrogenic, and thyroid pathways, with subsequent effects on normal endocrine and metabolic functions, which cause changes in the epigenome and state of inflammation with life-long effects and consequences. International scientific societies recommend the implementation of research and of all possible preventive measures. This review briefly summarizes all these aspects.

Sex-specific associations of insulin-like peptides in cord blood with size at birth

OBJECTIVE

Insulin-like peptides (insulin, IGF-1, IGF-2) are essential regulators of foetal growth. We assessed the role of these peptides for birth size in a sex-specific manner.

DESIGN

Cross-sectional cohort analysis.

PATIENTS AND MEASUREMENTS

In 369 neonates, cord blood insulin, C-peptide, IGF-1 and IGF-2 levels were measured. Outcomes were placenta weight, birthweight, length and ponderal index. In linear regression models, the association of insulin-like peptides with growth outcomes was assessed, adjusted for gestational age and delivery mode. Interaction between insulin-like peptides and neonatal sex was assessed.

RESULTS

No sex differences in levels of insulin-like peptides were observed. Significant interactions were found of sex with IGF-1 for birthweight, and of sex with C-peptide for all outcomes, except ponderal index. The association of IGF-1 (ng/mL) with birthweight was stronger and only significant in males (beta coefficient 3.30 g; 95%CI 1.98-4.63 in males and 1.45 g; -0.09-2.99 in females). Associations of C-peptide (ng/mL) with growth outcomes were stronger and only significant in females (placenta weight females: 181.3 g; 109.3-253.3; P < .001, males: 29.8 g; -51.5-111.1; P = .47, birthweight females: 598.5 g; 358.3-838.7: P < .001, males: 113.7 g; -154.0-381.4; P = .40). Associations of IGF2 with birthweight were similar in males and females. No associations were found with ponderal index.

CONCLUSIONS

C-peptide and IGF-1 in cord blood associate with birthweight, length and placenta weight in a sex-specific manner, with stronger associations of C-peptide levels with placenta weight, birthweight and length in females and stronger associations of IGF-1 levels with birthweight in males.

IGF2 stimulates fetal growth in a sex- and organ-dependent manner

BackgroundInsulin-like growth factor 2 (IGF2) is a key determinant of fetal growth, and the altered expression of IGF2 is implicated in fetal growth disorders and maternal metabolic derangements including gestational diabetes. Here we studied how increased levels of IGF2 in late pregnancy affect fetal growth.MethodsWe employed a rat model of repeated intrafetal IGF2 administration in late pregnancy, i.e., during GD19-GD21, and measured the consequences on fetal organ weight and expression of insulin/IGF-axis components.ResultsIGF2 treatment tended to increase fetal weight, but only weight increase of the fetal stomach reached significance (+33±9%; P<0.01). Sex-dependent data analysis revealed a sexual dimorphism of IGF2 action. In male fetuses, IGF2 administration significantly increased fetal weight (+13±3%; P<0.05) and weight of fetal stomach (+42±10%; P<0.01), intestine (+26±5%; P<0.05), liver (+13±4%; P<0.05), and pancreas (+25±8%; P<0.05). Weights of heart, lungs, and kidneys were unchanged. In female fetuses, IGF2 increased only stomach weight (+26±9%; P<0.05). Furthermore, gene expression of insulin/IGF axis in the heart, lungs, liver, and stomach was more sensitive toward IGF2 treatment in male than in female fetuses.ConclusionData suggest that elevated circulating IGF2 in late pregnancy predominantly stimulates organ growth of the digestive system, and male fetuses are more susceptible toward the IGF2 effects than female fetuses.

Effects of dietary advice on insulin-like growth factors among healthy newborns

OBJECTIVES

In fetal life, insulin, insulin-like growth factor (IGF) 1, IGF 2 and IGF-binding protein (IGFBP) 3 are essential growth factors. The purpose of this study is to investigate the effects of dietary intervention on insulin-like growth factors in the cord blood of neonates.

METHODS

The study involved 52 pregnant women who were followed up in Gazi University Medical School Hospital at Ankara, Turkey. They were randomly divided into two groups: The experimental group was involved in nutrition education. We measured IGF 1, IGF 2 and IGFBP 3 concentrations in cord blood from 52 neonates.

RESULTS

In the experimental group, cord serum levels of IGF 1, IGF 2 were observed to be higher than that of control group.

CONCLUSION

Dietary advice had positive effects on the cord serum IGF 1 and IGF 2 concentrations. Dietary advice during pregnancy proved to be effective in fetal development.

Gestational age and childhood leukemia: A meta-analysis of epidemiologic studies

OBJECTIVE

An increasing amount of evidence shows that childhood leukemia is initiated in utero. Birth characteristics initiated in utero, such as gestational age, may play a role in leukemogenesis. The purpose of our meta-analysis is to explore the association between gestational age and childhood leukemia.

METHODS

Relevant studies up to 21 April 2017 were collected by searching PubMed and EMBASE databases. Subgroup analysis, sensitivity analysis and publication bias assessment were conducted.

RESULTS

A total of 13 studies were included. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) for preterm birth and postterm birth were 1.06 (0.98, 1.13) and 1.01 (0.90, 1.13) for childhood leukemia, 1.04 (0.97, 1.11) and 1.03 (0.95, 1.12) for acute lymphocytic leukemia (ALL), 1.20 (1.00, 1.44) and 1.20 (1.00, 1.43) for acute myeloid leukemia (AML), compared with full-term birth. Study type and study region were the reasons behind the heterogeneity. In subgroup analyses, the summary ORs with 95% CI for childhood leukemia and ALL were 1.23 (1.07, 1.41) and 1.21 (1.06, 1.39) for postterm birth in cohort studies. No significant changes in sensitivity analyses and no publication bias were observed in our analysis.

CONCLUSION

Our results suggest that both preterm and postterm infants have an elevated risk of developing AML. In addition, postterm birth increased the risk of childhood leukemia and ALL in cohort studies. However, more studies are warranted to validate these results and explore the biologic mechanisms underlying these relationships.

Inflammatory Diseases and Growth: Effects on the GH-IGF Axis and on Growth Plate

This review briefly describes the most common chronic inflammatory diseases in childhood, such as cystic fibrosis (CF), inflammatory bowel diseases (IBDs), juvenile idiopathic arthritis (JIA), and intrauterine growth restriction (IUGR) that can be considered, as such, for the changes reported in the placenta and cord blood of these subjects. Changes in growth hormone (GH) secretion, GH resistance, and changes in the insulin-like growth factor (IGF) system are described mainly in relationship with the increase in nuclear factor-κB (NF-κB) and pro-inflammatory cytokines. Changes in the growth plate are also reported as well as a potential role for microRNAs (miRNAs) and thus epigenetic changes in chronic inflammation. Many mechanisms leading to growth failure are currently known; however, it is clear that further research in the field is still warranted.

Preliminary report of altered insulin secretion pattern in monochorionic twin pregnancies complicated with selective intrauterine growth restriction

OBJECTIVE

Fetuses with intrauterine growth restriction (IUGR) have adaptive hormonal changes including changes in insulin, which may increase their future risks for developing diabetes mellitus. This study compared cord blood insulin concentrations in IUGR and appropriate for gestational age (AGA) fetuses in a monochorionic (MC) twin model.

MATERIALS AND METHODS

Ten pairs were classified as selective IUGR (sIUGR) based on having one twin weight below the 10th percentile and with an intertwin birth weight discordance>20%. Fourteen pairs without IUGR were included as a comparison group. Pregnancies with twin-twin transfusion syndrome, congenital structural malformations, and genetic abnormalities were excluded. Insulin and glucose concentrations were measured in cord venous blood at the time of delivery.

RESULTS

Cord blood insulin concentrations of sIUGR fetuses were significantly lower than those of AGA counterpart fetuses in MC twins affected by sIUGR (5.1±4.1 mU/L, range: 0.7-9.9 mU/L for sIUGR fetuses and 12.2±7.6 mU/L, range: 3.5-23.7 mU/L for AGA fetuses, p=0.019). No significant difference in insulin concentrations between larger and smaller fetuses in MC twins without IUGR was observed. Insulin concentration was inversely correlated with gestational age of delivery in all fetuses except in those with sIUGR. We did not find any difference in cord blood glucose concentrations between the two fetuses in both groups.

CONCLUSION

Our data show reduced insulin secretion and loss of the physiological decline in concentration over time as gestational age increases in fetuses with sIUGR compared to AGA counterparts.

The Relationship of Insulin-Like Growth Factor 2 to Fetal Growth and Adiposity

Insulin-like growth factor 2 (IGF-2) is necessary for adequate human growth. Overexpression of the IGF2 gene is associated with fetal overgrowth and may play a role in the intrauterine programming of adipose tissue. As obesity in children is a major public health problem associated with early onset of comorbid metabolic diseases, identifying early life markers of obesity may serve as useful tool for counseling and implementation of preventive efforts before obesity develops. The relationship between IGF-2 and body composition is an emerging field of study and existing data are conflicting. In this review, we discuss the IGF2 gene and its function, highlight the proposed mechanisms for the effects of IGF-2 on adiposity, and examine the current literature studying the relationships between IGF-2 levels, changes within the IGF2 gene, weight, and adiposity. With additional study, IGF-2 may emerge as a useful marker of future obesity risk in infants.

Associations Among Child Abuse, Depression, and Interleukin-6 in Pregnant Adolescents: Paradoxical Findings

OBJECTIVE

Limited data exist on child abuse-related immune variation during pregnancy, despite implications for maternal and infant health and extensive data showing that abuse history and depression are related to increased inflammation in other populations. This study examined associations among child abuse, depression, circulating levels of inflammatory markers, and perinatal health in pregnant adolescents, a group at high risk for childhood abuse and poor birth outcomes.

METHODS

Pregnant teenagers (n = 133; 14-19 years; 89.5% Latina) reported on abuse and depression and had two blood draws (24-27 and 34-37 gestational weeks, second and third trimesters, respectively) for interleukin-6 (IL-6) and C-reactive protein; birth outcomes were collected.

RESULTS

Abuse and depression interacted to predict higher IL-6 at second trimester (B = 0.006, p = .011) such that severely abused adolescents with high depression had higher IL-6 relative to severely abused adolescents with low depression; depression did not differentiate IL-6 levels for those with low abuse severity. Abuse and IL-6 also interacted to predict gestational age at birth (B = 0.004, p = .040) such that those with low abuse and high IL-6 and those with high abuse and low IL-6 had infants with earlier gestational age at birth. Cortisol at the second trimester mediated the association between IL-6 and gestational age at birth (indirect effect estimate=-0.143, p < .039).

CONCLUSIONS

Depression severity distinguished IL-6 levels among more severely abused pregnant Latina adolescents, but it was unrelated to IL-6 among less severely abused adolescents. Cortisol explained the relationship between IL-6 and earlier gestational age at birth. Multiple adversities and inflammation may influence birth outcomes and potentially affect intergenerational health.

Early hypermethylation of hepatic Igfbp2 results in its reduced expression preceding fatty liver in mice

Obesity and ectopic fat disposition are risk factors for metabolic disease. Recent data indicate that IGFBP2 expression in liver is epigenetically inhibited during hepatic steatosis. The aim of this study was to investigate if epigenetic de-regulation of hepatic Igfbp2 occurs already early in life and is associated with increased risk for diet-induced obesity (DIO) during adolescence. Male C57BL/6J mice received a high-fat diet. After 3 weeks on this diet (age of 6 weeks), DIO-susceptible (responder, Resp) and DIO-resistant (non-responder, nResp) mice were identified by early weight gain. At the age of 6 weeks, Resp mice exhibited elevated blood glucose (p < 0.05), plasma insulin (p < 0.01), HOMA-IR and leptin/adiponectin ratio, whereas liver triglycerides were identical but significantly increased (p < 0.01) in Resp mice at 20 weeks of age. Igfbp2 expression was reduced in young Resp compared with nResp mice (p < 0.01), an effect that correlated with elevated DNA methylation of intronic CpG₂₆₀₅ (p < 0.01). The epigenetic inhibition of Igfbp2 was stable over time and preceded DIO and hepatosteatosis in adult mice. In vitro studies demonstrated that selective methylation of CpG₂₆₀₅ significantly reduced reporter activity by ∼85%, indicating that Igfbp2 expression is modulated by methylation. In human whole blood cells, methylation of IGFBP2 at the homologous CpG site was increased in obese men with impaired glucose tolerance. In conclusion, our data show that increased methylation of hepatic Igfbp2 during infancy predicts the development of fatty liver later in life and is linked to deterioration of glucose metabolism.

Physiology and pathophysiology of IGFBP-1 and IGFBP-2 - consensus and dissent on metabolic control and malignant potential

IGFBP-1 and IGFBP-2 are suppressed by growth hormone and therefore represent less prominent members of the IGFBP family when compared to IGFBP-3 that carries most of the IGFs during circulation under normal conditions in humans in vivo. As soon as the GH signal is decreased expression of IGF-I and IGFBP-3 is reduced. Under conditions of lowered suppression by GH the time seems come for IGFBP-1 and IGFBP-2. Both IGFBPs are potent effectors of growth and metabolism. Secretion of IGFBP-1 and IGFBP-2 is further suppressed by insulin and diminished with increasing obesity. Both IGFBP family members share the RGD sequence motif that mediates binding to integrins and is linked to PTEN/PI3K signalling. In mice, IGFBP-2 prevents age- and diet-dependent glucose insensitivity and blocks differentiation of preadipocytes. The latter function is modulated by two distinct heparin-binding domains of IGFBP-2 which are lacking in IGFBP-1. IGFBP-2 is further regulated by leptin and has been demonstrated to affect insulin sensitivity and glucose tolerance, further supporting a particular role of IGFBP-2 in glucose and fat metabolism. Since IGFBP-2 is controlled by sex steroids as well, we devised a scheme to compare IGFBP effects in breast, ovarian and prostate cancer. While a positive association does not seem to exist with IGFBP-1 and risk of cancers within these reproductive tissues, a relationship between IGFBP-2 and breast cancer, ovarian cancer and prostate cancer does indeed appear to be present. To date, the specific roles of IGFBP-2 in estrogen signalling are unclear, though there is accumulating evidence for an effect of IGFBP-2 on PI3K signalling via PTEN, particularly in breast cancer.

The biomarkers of fetal growth in intrauterine growth retardation and large for gestational age cases: from adipocytokines to a metabolomic all-in-one tool

Adipose tissue is no longer considered as inert; the literature describes the role it plays in the production of many substances, such as adiponectin, visfatin, ghrelin, S100B, apelin, TNF, IL-6 and leptin. These molecules have specific roles in humans and their potential as biomarkers useful for identifying alterations related to intrauterine growth retardation and large for gestational age neonates is emerging. Infants born in such conditions have undergone metabolic changes, such as fetal hypo- or hyperinsulinemia, which may lead to development of dysmetabolic syndrome and other chronic diseases in adulthood. In this review, these biomarkers are analyzed specifically and it is discussed how metabolomics may be an advantageous tool for detection, discrimination and prediction of metabolic alterations and diseases. Thus, a holistic approach, such as metabolomics, could help the prevention and early diagnosis of metabolic syndrome.

IGFBP-2 - taking the lead in growth, metabolism and cancer

The activity of the Insulin-like Growth Factors (IGFs) ligands elicited via their receptors and transduced by various intracellular signal pathways is modulated by the IGF Binding Proteins (IGFBPs). Among all the IGFBPs, IGFBP-2 has been implicated in the regulation of IGF activity in most tissue and organs. Besides binding to IGFs in the circulation these IGF-regulatory activities of IGFBP-2 involve interactions with components of the extracellular matrix, cell surface proteoglycans and integrin receptors. In addition to these local peri-cellular activities, IGFBP-2 exerts other key functions within the nucleus, where IGFBP-2 directly or indirectly promotes transcriptional activation of specific genes. All of these IGFBP-2 activities, intrinsic or dependent on IGFs, contribute to its functional roles in growth/development, metabolism and malignancy as evidenced by studies in IGFBP-2 animal models and also by many in vitro studies. Finally, preclinical studies have demonstrated that IGFBP-2 administration can be beneficial in improving metabolic responses (inhibition of adipogenesis and enhanced insulin sensitivity), while blockade of IGFBP-2 appears to be an effective approach to inhibiting tumour growth and metastasis.

Data Mining of Determinants of Intrauterine Growth Retardation Revisited Using Novel Algorithms Generating Semantic Maps and Prototypical Discriminating Variable Profiles

OBJECTIVES

Intra-uterine growth retardation is often of unknown origin, and is of great interest as a "Fetal Origin of Adult Disease" has been now well recognized. We built a benchmark based upon a previously analysed data set related to Intrauterine Growth Retardation with 46 subjects described by 14 variables, related with the insulin-like growth factor system and pro-inflammatory cytokines, namely interleukin-6 and tumor necrosis factor-α.

DESIGN AND METHODS

We used new algorithms for optimal information sorting based on the combination of two neural network algorithms: Auto-contractive Map and Activation and Competition System. Auto-Contractive Map spatializes the relationships among variables or records by constructing a suitable embedding space where 'closeness' among variables or records reflects accurately their associations. The Activation and Competition System algorithm instead works as a dynamic non linear associative memory on the weight matrices of other algorithms, and is able to produce a prototypical variable profile of a given target.

RESULTS

Classical statistical analysis, proved to be unable to distinguish intrauterine growth retardation from appropriate-for-gestational age (AGA) subjects due to the high non-linearity of underlying functions. Auto-contractive map succeeded in clustering and differentiating completely the conditions under study, while Activation and Competition System allowed to develop the profile of variables which discriminated the two conditions under study better than any other previous form of attempt. In particular, Activation and Competition System showed that ppropriateness for gestational age was explained by IGF-2 relative gene expression, and by IGFBP-2 and TNF-α placental contents. IUGR instead was explained by IGF-I, IGFBP-1, IGFBP-2 and IL-6 gene expression in placenta.

CONCLUSION

This further analysis provided further insight into the placental key-players of fetal growth within the insulin-like growth factor and cytokine systems. Our previous published analysis could identify only which variables were predictive of fetal growth in general, and identified only some relationships.

The role of placental nutrient sensing in maternal-fetal resource allocation

The placenta mediates maternal-fetal exchange and has historically been regarded as a passive conduit for nutrients. However, emerging evidence suggests that the placenta actively responds to nutritional and metabolic signals from the mother and the fetus. We propose that the placenta integrates a multitude of maternal and fetal nutritional cues with information from intrinsic nutrient-sensing signaling pathways to match fetal demand with maternal supply by regulating maternal physiology, placental growth, and nutrient transport. This process, which we have called placental nutrient sensing, ensures optimal allocation of resources between the mother and the fetus to maximize the chances for propagation of parental genes without jeopardizing maternal health. We suggest that these mechanisms have evolved because of the evolutionary pressures of maternal undernutrition, which result in decreased placental growth and down-regulation of nutrient transporters, thereby limiting fetal growth to ensure maternal survival. These regulatory loops may also function in response to maternal overnutrition, leading to increased placental growth and nutrient transport in cases of maternal obesity or gestational diabetes. Thus, placental nutrient sensing modulates maternal-fetal resource allocation to increase the likelihood of reproductive success. This model implies that the placenta plays a critical role in mediating fetal programming and determining lifelong health.

Maternal nutritional history modulates the hepatic IGF-IGFBP axis in adult male rat offspring

Alterations in early life nutrition lead to an increased risk of obesity and metabolic syndrome in offspring. We have shown that both relative maternal undernutrition (UN) and maternal obesity result in metabolic derangements in offspring, independent of the postnatal dietary environment. Since insulin-like growth factor binding protein 2 (IGFBP2) has been shown to be independently associated with obesity and diabetes risk, we examined the IGF-IGFBP axis in male rat offspring following either maternal UN or maternal obesity to explain possible common pathways in the development of metabolic disorders. Wistar rats were time-mated and fed either a control diet (CONT), 50 % of CONT (UN) or a high-fat (HF) diet throughout pregnancy. Male offspring were weaned onto a standard chow diet and blood and tissues were collected at postnatal day 160. Plasma and hepatic tissue samples were analysed for key players in the IGF-IGFBP system. Both maternal UN and HF resulted in increased fat mass, hyperinsulinemia, hyperleptinemia and altered blood lipid profiles in offspring compared to CONT. Circulating IGF-1 and IGFBP3 levels and hepatic mRNA expression of IGFBP1 and IGFBP2 were significantly decreased in UN and HF offspring compared to CONT. DNA methylation of the IGFBP2 promotor region was similar between maternal dietary groups. Although chaperone gene heat-shock protein 90 and hepatic IGFBP1 were significantly correlated in CONT offspring this effect was absent in both UN and HF offspring. In conclusion, this study is one of the first to directly compare two experimental models of developmental programming representing both ends of the maternal dietary spectrum. Our data suggest that two disparate nutritional models that elicit similar adverse metabolic phenotypes in offspring are characterised by common alterations in the IGF-IGFBP pathway.

Inflammatory markers in umbilical cord blood from small-for-gestational-age newborns

This study investigates the role of inflammation in intrauterine growth retardation by exploring the levels of inflammatory markers in umbilical cord blood from neonates who were born small-for-gestational-age (SGA) and comparing them to neonates who were born appropriate-for-gestational-age (AGA). Interleukin 6 (IL-6), Tumor necrosis factor-α (TNF-α) and C-reactive protein (CRP) were measured by standard methods in term or near-term (gestational age >36 weeks) neonates born SGA (n = 45) and a matched group of neonates born AGA (n = 45). Infants exposed to maternal chronic diseases, diabetes or pre-eclampsia were excluded. SGA was defined as two standard derivations below the expected for term and gender. In multivariate regression analyses significant elevation in cord blood concentration of IL-6 was demonstrated in the SGA group (mean 4.56 vs. 2.38, p = 0.002). The results indicate the presence of elevated inflammatory markers in the cord blood from SGA infants compared to AGA infants, and consequently the results suggest an inflammatory component in intrauterine growth restriction (IUGR).

Risk for late-onset blood-culture proven sepsis in very-low-birth weight infants born small for gestational age: a large multicenter study from the German Neonatal Network

BACKGROUND

It was the aim of this study to assess whether very-low-birth-weight (VLBW) infants born small for gestational age (SGA; birth weight less than 10th percentile) are at increased risk for late-onset sepsis.

METHODS

This was a prospective, multicenter study of the German Neonatal Network including VLBW infants from 23 to < 32 weeks post menstrual age born 2009-2011. Outcomes were compared between VLBW infants born SGA (birth weight less than tenth percentile according to gestational age and gender) and non-SGA infants. The main outcome measure was at least 1 episode of late-onset sepsis defined as blood-culture-confirmed clinical sepsis occurring at ≥ 72 hours of age.

RESULTS

5886 VLBW infants were included. In SGA infants (n = 692), an increased incidence of late-onset sepsis was noted compared with non-SGA infants (20.1% vs. 14.3 %, P < 0.001). This difference was only observed among infants with a gestational age of 27 to < 32 weeks and attributed to sepsis episodes with coagulase-negative staphylococci (12.8% vs. 8.3%, P < 0.001). Different treatment modalities (eg more frequent use of central venous lines) and longer duration of invasive therapies (parenteral nutrition, mechanical ventilation, hospitalization) may account for the increased sepsis risk with coagulase-negative staphylococci in our SGA cohort. In a multivariate logistic regression analysis, higher gestational age [per week; odds ratio (OR): 0.75, 95% confidence interval (CI): 0.72-0.78, P< 0.0001], treatment with antenatal steroids (OR: 0.7, 95% CI: 0.53-0.92, P = 0.01), German descendance (OR: 0.76, 95% CI: 0.63-0.91, P = 0.003) and prophylaxis with glycopeptide antibiotics (OR: 0.64, 95% CI: 0.47-0.87, P = 0.005) were shown to be protective against late-onset sepsis. In contrast, longer duration of parenteral nutrition (per day; OR: 1.016, 95% CI: 1.011-1.021, P < 0.0001) and SGA were found to be risk factors (OR: 1.31, 95% CI: 1.02-1.68, P= 0.03).

CONCLUSIONS

SGA contributes to the risk of late-onset sepsis in VLBW infants. Future studies are needed to investigate the underlying pathophysiology to guide individualized preventive measures in this vulnerable subgroup.

Paternally expressed, imprinted insulin-like growth factor-2 in chorionic villi correlates significantly with birth weight

Context

Fetal growth involves highly complex molecular pathways. IGF2 is a key paternally expressed growth hormone that is critical for in utero growth in mice. Its role in human fetal growth has remained ambiguous, as it has only been studied in term tissues. Conversely the maternally expressed growth suppressor, PHLDA2, has a significant negative correlation between its term placental expression and birth weight.

Objective

The aim of this study is to address the role in early gestation of expression of IGF1, IGF2, their receptors IGF1R and IGF2R, and PHLDA2 on term birth weight.

Design

Real-time quantitative PCR was used to investigate mRNA expression of IGF1, IGF2, IGF1R, IGF2R and PHLDA2 in chorionic villus samples (CVS) (n = 260) collected at 11–13 weeks' gestation. Expression was correlated with term birth weight using statistical package R including correction for several confounding factors.

Results

Transcript levels of IGF2 and IGF2R revealed a significant positive correlation with birth weight (0.009 and 0.04, respectively). No effect was observed for IGF1, IGF1R or PHLDA2 and birth weight. Critically, small for gestational age (SGA) neonates had significantly lower IGF2 levels than appropriate for gestational age neonates (p = 3·6×10⁻⁷).

Interpretation

Our findings show that IGF2 mRNA levels at 12 weeks gestation could provide a useful predictor of future fetal growth to term, potentially predicting SGA babies. SGA babies are known to be at a higher risk for type 2 diabetes. This research reveals an imprinted, parentally driven rheostat for in utero growth.

DNA methylation of IGF2DMR and H19 is associated with fetal and infant growth: the generation R study

Changes in epigenetic programming of embryonic growth genes during pregnancy seem to affect fetal growth. Therefore, in a population-based prospective birth cohort in the Netherlands, we examined associations between fetal and infant growth and DNA methylation of IGF2DMR, H19 and MTHFR. For this study, we selected 69 case children born small-for-gestational age (SGA, birth weight <-2SDS) and 471 control children. Fetal growth was assessed with serial ultrasound measurements. Information on birth outcomes was retrieved from medical records. Infant weight was assessed at three and six months. Methylation was assessed in DNA extracted from umbilical cord white blood cells. Analyses were performed using linear mixed models with DNA methylation as dependent variable. The DNA methylation levels of IGF2DMR and H19 in the control group were, median (90% range), 53.6% (44.5-61.6) and 30.0% (25.6-34.2) and in the SGA group 52.0% (43.9-60.9) and 30.5% (23.9-32.9), respectively. The MTHFR region was found to be hypomethylated with limited variability in the control and SGA group, 2.5% (1.4-4.0) and 2.4% (1.5-3.8), respectively. SGA was associated with lower IGF2DMR DNA methylation (β = -1.07, 95% CI -1.93; -0.21, P-value = 0.015), but not with H19 methylation. A weight gain in the first three months after birth was associated with lower IGF2DMR DNA methylation (β = -0.53, 95% CI -0.91; -0.16, P-value = 0.005). Genetic variants in the IGF2/H19 locus were associated with IGF2DMR DNA methylation (P-value<0.05), but not with H19 methylation. Furthermore, our results suggest a possibility of mediation of DNA methylation in the association between the genetic variants and SGA. To conclude, IGF2DMR and H19 DNA methylation is associated with fetal and infant growth.

Artificial Neural Networks, and Evolutionary Algorithms as a systems biology approach to a data-base on fetal growth restriction

One of the specific aims of systems biology is to model and discover properties of cells, tissues and organisms functioning. A systems biology approach was undertaken to investigate possibly the entire system of intra-uterine growth we had available, to assess the variables of interest, discriminate those which were effectively related with appropriate or restricted intrauterine growth, and achieve an understanding of the systems in these two conditions. The Artificial Adaptive Systems, which include Artificial Neural Networks and Evolutionary Algorithms lead us to the first analyses. These analyses identified the importance of the biochemical variables IL-6, IGF-II and IGFBP-2 protein concentrations in placental lysates, and offered a new insight into placental markers of fetal growth within the IGF and cytokine systems, confirmed they had relationships and offered a critical assessment of studies previously performed.

Effects of maternal obstructive sleep apnoea on fetal growth: a prospective cohort study

OBJECTIVE

The objective of this study is to determine whether obstructive sleep apnea (OSA) is associated with reduced fetal growth, and whether nocturnal oxygen desaturation precipitates acute fetal heart rate changes.

STUDY DESIGN

We performed a prospective observational study, screening 371 women in the second trimester for OSA symptoms. 41 subsequently underwent overnight sleep studies to diagnose OSA. Third trimester fetal growth was assessed using ultrasound. Fetal heart rate monitoring accompanied the sleep study. Cord blood was taken at delivery, to measure key regulators of fetal growth.

RESULTS

Of 371 women screened, 108 (29%) were high risk for OSA. 26 high risk and 15 low risk women completed the longitudinal study; 14 had confirmed OSA (cases), and 27 were controls. The median (interquartile range) respiratory disturbance index (number of apnoeas, hypopnoeas or respiratory related arousals/hour of sleep) was 7.9 (6.1-13.8) for cases and 2.2 (1.3-3.5) for controls (p<0.001). Impaired fetal growth was observed in 43% (6/14) of cases, vs 11% (3/27) of controls (RR 2.67; 1.25-5.7; p = 0.04). Using logistic regression, only OSA (OR 6; 1.2-29.7, p = 0.03) and body mass index (OR 2.52; 1.09-5.80, p = 0.03) were significantly associated with impaired fetal growth. After adjusting for body mass index on multivariate analysis, the association between OSA and impaired fetal growth was not appreciably altered (OR 5.3; 0.93-30.34, p = 0.06), although just failed to achieve statistical significance. Prolonged fetal heart rate decelerations accompanied nocturnal oxygen desaturation in one fetus, subsequently found to be severely growth restricted. Fetal growth regulators showed changes in the expected direction- with IGF-1 lower, and IGFBP-1 and IGFBP-2 higher- in the cord blood of infants of cases vs controls, although were not significantly different.

CONCLUSION

OSA may be associated with reduced fetal growth in late pregnancy. Further evaluation is warranted to establish whether OSA may be an important contributor to adverse perinatal outcome, including stillbirth.

Do Biochemical Markers and Apa I Polymorphism in IGF-II Gene Play a Role in the Association of Birth Weight and Later BMI?

BACKGROUND

The aim of the study was to explore the mechanisms underlying the association of birth weight with later body mass index (BMI) from the biochemical markers related to metabolism and the Apa I polymorphism in IGF-II gene.

METHODS

A total of 300 children were selected randomly from the Macrosomia Birth Cohort in Wuxi, China. The height and weight were measured and blood samples were collected. Plasma concentrations of 8 biochemical markers were detected. Apa I polymorphism was analyzed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP).

RESULTS

Biochemical markers were detected for 296 subjects and 271 subjects were genotyped for the Apa I polymorphism. No association was found between birth weight and 8 biochemical markers. In boys, the BMIs of AA, AG and GG genotypes were 16.10 ± 2.24 kg/m(2), 17.40 ± 3.20 kg/m(2), 17.65 ± 2.66 kg/m(2). And there was statistical difference among the three genotypes. But in girls, there was no statistical difference. The birth weights of AA, AG and GG genotypes were 3751.13 ± 492.43 g, 3734.00 ± 456.88 g, 3782.00 ± 461.78 g. And there was no statistical difference among the three genotypes.

CONCLUSION

Biochemical markers are not associated with birth weight. Apa I polymorphism may be related to childhood BMI, but it may be not associated with birth weight. Therefore, biochemical markers and Apa I polymorphism might not play a role in the association of birth weight and BMI.

Placental transport in response to altered maternal nutrition

The mechanisms linking maternal nutrition to fetal growth and programming of adult disease remain to be fully established. We review data on changes in placental transport in response to altered maternal nutrition, including compromized utero-placental blood flow. In human intrauterine growth restriction and in most animal models involving maternal undernutrition or restricted placental blood flow, the activity of placental transporters, in particular for amino acids, is decreased in late pregnancy. The effect of maternal overnutrition on placental transport remains largely unexplored. However, some, but not all, studies in women with diabetes giving birth to large babies indicate an upregulation of placental transporters for amino acids, glucose and fatty acids. These data support the concept that the placenta responds to maternal nutritional cues by altering placental function to match fetal growth to the ability of the maternal supply line to allocate resources to the fetus. On the other hand, some findings in humans and mice suggest that placental transporters are regulated in response to fetal demand signals. These observations are consistent with the idea that fetal signals regulate placental function to compensate for changes in nutrient availability. We propose that the placenta integrates maternal and fetal nutritional cues with information from intrinsic nutrient sensors. Together, these signals regulate placental growth and nutrient transport to balance fetal demand with the ability of the mother to support pregnancy. Thus, the placenta plays a critical role in modulating maternal-fetal resource allocation, thereby affecting fetal growth and the long-term health of the offspring.

Evidence that Igf2 down-regulation in postnatal tissues and up-regulation in malignancies is driven by transcription factor E2f3

Insulin-like growth factor 2 (IGF2) is an important fetal growth factor. Its expression is dramatically down-regulated in multiple organs after birth but is frequently up-regulated in cancers. The mechanisms that drive down-regulation of IGF2 in postnatal tissues or the up-regulation in malignancy are unclear. We found evidence that E2F transcription factor 3 (E2F3) drives these changes in expression. E2f3 mRNA expression, protein expression, and binding to the Igf2 promoter all decreased with age postnatally in multiple mouse organs. In late juvenile hepatocytes, restoration of high E2f3 expression restored high Igf2 expression, indicating a causal relationship, but this induction did not occur in fetal hepatocytes, which already have high E2f3 and Igf2 expression. Transient expression of E2f3 in both HEK293 cells and in late juvenile hepatocytes were able to activate reporter constructs containing the mouse Igf2 promoter P2, which includes consensus E2F-binding sites. In humans, microarray data revealed declines in E2F3 and IGF2 expression with age similar to the mouse. In addition, E2F3-overexpressing human prostate and bladder cancers showed increased IGF2 expression, and levels of E2F3 and IGF2 mRNA in these cancers were positively correlated. Taken together, the findings suggest that down-regulation of E2f3 with age helps drive the dramatic decline in Igf2 expression in postnatal organs, and E2F3 overexpression in human cancers induces IGF2 overexpression.

miR-141 contributes to fetal growth restriction by regulating PLAG1 expression

Background

Fetal growth restriction (FGR) is an important but poorly understood condition of pregnancy, which results in significant fetal, neonatal and long-term morbidity and mortality. Novel research has suggested that altered miRNA expression in the plasma and placenta is associated with adverse pregnancy. We hypothesized that aberrant expression of microRNA-141 (miR-141) in the placenta is associated with FGR. Additionally, expression levels of predicted target genes of miR-141 were also analyzed in placental tissues of FGR and normal controls.

Methodology/Principal Findings

Using quantitative real time PCR, we analyzed the expression level of miR-141 and its target genes in placentas of FGR pregnancies (n = 21) and normal controls (n = 34). Western blot was used to detect the protein expression level of the target genes of miR-141. MiR-141 showed significant up regulation in FGR and significant down regulation of its targets, i.e. E2F transcription factor 3 (E2F3) protein, pleiomorphic adenoma gene 1 (PLAG1) mRNA and protein. Moreover, a positive correlation was found between PLAG1 and insulin-like growth factor 2 (IGF2) expression levels (Spearman r = 0.56, p<0.0001). MiR-141 yields an AUC of 0.83 with 88.5% sensitivity and 71.7% specificity for separating FGR from normal controls. This study indicates that miR-141 may be diagnostically important in FGR.

Conclusions/Significance

Our results indicate that aberrant high expression level of miR-141 might play important roles in the pathogenesis of FGR by suppressing E2F3 and PLAG1. We propose that miR-141 may participate in a miR-141-PLAG1-IGF2 network relating to FGR development. These findings may provide new targets via miR-141 in diagnosis and therapy of FGR in the future.

Intrauterine growth restriction and the innate immune system in preterm infants of ≤32 weeks gestation

OBJECTIVE

Intrauterine growth restriction (IUGR) is a well-known cause of adverse neonatal outcomes. As it may have an impact on innate immune responses, we aimed to investigate several parameters of the innate immune response in preterm infants of ≤32 weeks gestation who were small for gestational age (SGA).

METHODS

We compared clinical data of SGA (n = 20) and appropriate for gestational age (AGA; n = 124) newborns with a gestational age of ≤32 weeks. We investigated full blood counts at birth and on days 3 and 7 of life and cytokine immune responses in a human whole cord blood assay.

RESULTS

SGA preterm infants had a higher risk of the combined outcome mortality or bronchopulmonary dysplasia. Numbers of white blood cells and neutrophils were diminished in SGA infants at birth and on day 3. At birth, platelet counts were also diminished while the number of nucleated red blood cells tended to be elevated in SGA infants. After stimulation of whole blood cell cultures with lipopolysaccharides, the concentrations of interleukin-6 and interleukin-10 were significantly lower in SGA preterm infants compared to AGA infants.

CONCLUSIONS

SGA infants differ remarkably from AGA infants in full blood counts and in their ability to mount an immune response. Whether the quantitative deficiency in innate immunity plays a role for adverse outcomes needs to be investigated in larger future trials.

Regulation of nutrient transport across the placenta

Abnormal fetal growth, both growth restriction and overgrowth, is associated with perinatal complications and an increased risk of metabolic and cardiovascular disease later in life. Fetal growth is dependent on nutrient availability, which in turn is related to the capacity of the placenta to transport these nutrients. The activity of a range of nutrient transporters has been reported to be decreased in placentas of growth restricted fetuses, whereas at least some studies indicate that placental nutrient transport is upregulated in fetal overgrowth. These findings suggest that changes in placental nutrient transport may directly contribute to the development of abnormal fetal growth. Detailed information on the mechanisms by which placental nutrient transporters are regulated will therefore help us to better understand how important pregnancy complications develop and may provide a foundation for designing novel intervention strategies. In this paper we will focus on recent studies of regulatory mechanisms that modulate placental transport of amino acids, fatty acids, and glucose.

Copeptin: a marker for stress reaction in fetuses with intrauterine growth restriction

OBJECTIVE

To compare venous cord plasma concentrations of 4 vasoactive peptide precursors: carboxy-terminal proarginine vasopressin, CT-prondothelin (ET)-1, midregional proadrenomedullin, and MR-proatrial natriuretic peptide, between fetuses with intrauterine growth restriction and appropriate for gestational age controls.

STUDY DESIGN

Matched-pair analysis of 12 fetuses with significant intrauterine growth restriction and 42 healthy appropriate for gestational age control fetuses. All infants were singletons, delivered by elective section after 34 weeks and without chromosomal abnormalities.

RESULTS

Umbilical cord plasma copeptin levels (median [range]) were 4-fold higher in intrauterine growth restriction infants than in matched appropriate for gestational age controls: 23.2 (6.7-449) vs 5.1 (2.5-53) pmol/L (P < .001). Multivariate regression analysis revealed an association between copeptin and umbilical artery resistance index z-score (P = .034). The 3 other precursor peptides showed no changes.

CONCLUSION

High copeptin concentrations in the cord blood of intrauterine growth restriction newborns reflect a fetal stress response and support the fetal programming hypothesis.