Relation of cord plasma concentrations of proinsulin, 32-33 split proinsulin, insulin and C-peptide to placental weight and the baby's size and proportions at birth

Sex differences in lipids: A life course approach

Differences between men and women in lipids and lipoproteins are observed in distribution and trajectory from infancy to adulthood in the general population. However, these differences are more pronounced in hereditary lipid disorders such as familial hypercholesterolemia (FH) when absolute cholesterol levels are higher from birth onwards. In the early life course, girls compared to boys have higher low-density lipoprotein cholesterol (LDL-C) levels and total cholesterol, while high-density lipoprotein cholesterol (HDL-C) levels are similar. In early adulthood to middle-age, women have lower LDL-C and higher HDL-C levels, as LDL-C levels increase and HDLC levels decrease in men. In the elderly, all lipids - total cholesterol, LDL-C, HDL-C and triglyceride levels decrease but are more pronounced in men. Lipid levels are also affected by specific transitions in girls/women such as the menstrual cycle, pregnancy, breastfeeding and menopause. Lipid levels fluctuate during the menstrual cycle. During pregnancy a physiological increase of LDL-C and even a larger increase in triglyceride levels are observed. Pregnancy has a double impact on LDL-C accumulation in women with FH as they have to stop statins, and the absolute increase in LDL-C is higher than in women without FH. In the menopausal transition, women develop a more adverse lipid profile. Therefore, it is important to take into account both sex and the life course when assessing a lipid profile.

The Melatonin and Enriched Environment Ameliorated Low Protein-Induced Intrauterine Growth Retardation by IGF-1 And mtor Signaling Pathway and Autophagy Inhibition in Rats

CDATA[Aim: The present study investigated whether melatonin (MEL) and enriched environment (EE) might protect against intrauterine growth retardation (IUGR) in rats.

METHODS

Sprague-Dawley rats were randomly allocated to 3 groups: control (C), model (M) and EE+MEL group. Animals were housed in an enriched environment (EE+MEL group) or remained in a standard environment (C group, M group). IUGR rat model was built by feeding a low protein diet during pregnancy. MEL was administered by gavaging. At day 1 post-birth, the baseline characteristics and serum biochemical parameters, morphology of liver and small intestine, enzyme activities, and mRNA expression levels of fetal rats were determined. The autophagy marker LC3 and Beclin1 were determined by western blot analysis.

RESULTS

EE+MEL markedly improved the baseline characteristics, hepatic and intestinal morphology of IUGR fetuses. In addition, the lactase activities in the fetal intestine were markedly increased by the EE+MEL. The levels of serum somatostatin (SST), Growth hormone (GH), GH releasing hormone (GHRH), Insulin-like Growth Factor 1 (IGF-1), triiodothyronine (T3), and tetraiodothyronine (T4) were found to be recovered by EE+MEL. In addition, the EE+MEL significantly ameliorated the mRNA expression of SST, GHRH, and GHRH receptor (GHRHR), GH, GHR, IGF-1, and IGF-1 receptor (IGF1R), IGF binding protein-1 (IGFBP1), mammalian target of rapamycin (mTOR), S6 kinase 1 (S6K1) and eukaryotic initiation factor 4E (eIF4E)-binding protein 1 (4EBP1) in fetuses. In IUGR fetal livers, LC3 and Beclin1 were found to be increased at birth, while LC3 and Beclin1 were observed to be significantly decreased in the EE+MEL group.

CONCLUSION

EE+MEL could improve fetal rats' baseline characteristics, serum biochemical parameters, birth weight, intestinal and hepatic morphology and enzyme activities. These effects could be explained by the activation of the IGF-1/IGFBP1 and IGF-1/mTOR/S6K1/4EBP1 signaling pathway and autophagy inhibition.

[Insulin Difference of Boys and Girls at Birth]

BACKGROUND

Different opinions exist whether girls show higher insulin levels than boys at birth. Insulin values of 863 consecutively born babies whose mothers had no screening for gestational diabetes may provide clarification.

METHOD

Cord serum, measured with a commercially available insulin assay, is therefore retrospectively analyzed for insulin differences in boys and girls.

RESULTS

Girls show higher insulin values than boys (♀6.0/♂5.2 µU/ml). Insulin-sex-difference amounts to 0.8 µU/ml [95% CI 0.3 to 1.3]; p-value 0.003. It is also found in AGA babies, in children of multiparous women, after elective caesarean section and spontaneous vaginal delivery (0.8/1.2/1.7/0.9 µU/ml; p-values 0.003/0.001/0.025/0.006). Girls of multiparous women with macrosomia (LGA/≥ 4000 g) show the highest values of insulin (13.8/13.8 µU/ml) and of insulin-sex-difference (5.5/5.6 µU/ml, p-value 0.001/0.001). This insulin difference can be seen in firstborn babies weighing less than 3640 g, but ≥ 4060 g an inverse insulin sex difference (-5.4 µU/ml; p-value 0.023) with higher insulin values in boys exists (11.3 µU/ml). Children with hyperinsulinaemia (≥20 µU/ml) (17♀, 11♂) show no insulin difference, girls weigh more than boys (154 g, p-value 0.463) and later born babies more (695 g, p-value 0.0001) than firstborns.

CONCLUSION

Higher insulin values of girls have been confirmed. An as yet unknown inverse insulin difference with higher insulin values of firstborn boys with macrosomia has been proved.

Hormonal Changes Associated With Intra-Uterine Growth Restriction: Impact on the Developing Brain and Future Neurodevelopment

The environment in which a fetus develops is not only important for its growth and maturation but also for its long-term postnatal health and neurodevelopment. Several hormones including glucocorticosteroids, estrogens and progesterone, insulin growth factor and thyroid hormones, carefully regulate the growth of the fetus and its metabolism during pregnancy by controlling the supply of nutrients crossing the placenta. In addition to fetal synthesis, hormones regulating fetal growth are also expressed and regulated in the placenta, and they play a key role in the vulnerability of the developing brain and its maturation. This review summarizes the current understanding and evidence regarding the involvement of hormonal dysregulation associated with intra-uterine growth restriction and its consequences on brain development.

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.

Assessing the growth of preterm infants using detailed anthropometry

AIM

Preterm infants display altered body composition compared to term infants, and weight gain is a crude indicator body composition. Childhood mid-upper arm circumference (MUAC) is a measure of nutritional status. This study investigates MUAC and mid-thigh circumference (MTC) to monitor growth in preterm infants.

METHODS

Preterm infants (<30-week gestation) were recruited. MUAC, MTC, weight, length and head circumference (HC) were measured at recruitment and weekly intervals until discharge. Descriptive, correlation and regression analyses were used.

RESULTS

Ninety-three infants were recruited. Median measurement duration was eight weeks (1-19). Median gestational age was 27 weeks (23-29). Analysis by curve estimation displayed a mean increase of 2.58 mm/week (left MUAC) (p ≤ 0.0001), 2.56 mm/week (right MUAC) (p ≤ 0.0001), 4.16 mm/week (left MTC) (p ≤ 0.0001), 4.20 mm/week (right MTC) (p ≤ 0.0001). Coefficients of determination (R² ) were calculated using a growth regression model for MUAC and MTC (0.866-0.917); measures were comparable to growth modelling of weight (0.913), length (0.945) and HC (0.928). High concordance between left and right MUAC and MTC generated a Pearson's correlation coefficient of 0.999 (MUAC) (p ≤ 0.001) and 0.994 (MTC) (p ≤ 0.001).

CONCLUSION

Data demonstrate the potential utility of MUAC and MTC as additional measures of growth in preterm infants that are reproducible over time. There is potential to gain insights to improve lean-mass accretion in preterm infants.

Insulin receptor isoforms: an integrated view focused on gestational diabetes mellitus

The human insulin receptor (IR) exists in two isoforms that differ by the absence (IR-A) or the presence (IR-B) of a 12-amino acid segment encoded by exon 11. Both isoforms are functionally distinct regarding their binding affinities and intracellular signalling. However, the underlying mechanisms related to their cellular functions in several tissues are only partially understood. In this review, we summarize the current knowledge in this field regarding the alternative splicing of IR isoform, tissue-specific distribution and signalling both in physiology and disease, with an emphasis on the human placenta in gestational diabetes mellitus (GDM). Furthermore, we discuss the clinical relevance of IR isoforms highlighted by findings that show altered insulin signalling due to differential IR-A and IR-B expression in human placental endothelium in GDM pregnancies. Future research and clinical studies focused on the role of IR isoform signalling might provide novel therapeutic targets for treating GDM to improve the adverse maternal and neonatal outcomes.

Association of the intronic polymorphism rs12540874 A>G of the GRB10 gene with high birth weight

BACKGROUND

High birth weight (HBW) is considered a key predictor of the development of chronic diseases, such as Type 2 Diabetes (T2D). Foetal growth depends on many factors, among which placental function is critical. Some genes with expression in the placenta, such as GRB10, are known to be involved in the regulation of insulin receptor pathways and the size of mouse littermates.

AIM

To evaluate whether the intronic polymorphism rs12540874 A>G of the GRB10 gene is associated with HBW in term newborns.

STUDY DESIGN

A total of 51 healthy term newborns were enrolled in a nested case-control study. The case group was defined by the presence of HBW (n=17) and the control group by newborns with normal birth weight (NBW n=34). Maternal and foetal factors influencing HBW were considered as exclusion criteria. The polymorphism was determined through real-time PCR using TaqMan technology. Categorical variables were evaluated with descriptive statistics, and multivariate logistic regression analysis was used to evaluate the association between polymorphism and HBW.

RESULTS

The newborns in the case group had a longer gestation period (39. 7 ± 1.0 and 38.8 ± 1.8 weeks) and higher insulin levels at birth (9.5 ± 4.0 and 5.7 ± 3.4 μU/mL) than the newborns in the control group. The multivariate regression analysis, adjusted for weeks of gestation, showed a significant association between the SNP rs12540874 A>G of the GRB10 gene with HBW (OR 4.9; CI95% 1.10-22.10 p=0.02).

CONCLUSIONS

Our results suggest that the SNP rs12540874 A>G, an intronic SNP of the gene GRB10, is associated with HBW.

Low birth weight and elevated head-to-abdominal circumference ratio are associated with elevated fetal glycated serum protein concentrations

OBJECTIVE

To analyze the association between low birth weight, head-to-abdominal circumference ratio, and insulin resistance in early life.

METHOD AND RESULTS

Glycated serum proteins (GSPs) were quantified at delivery in 612 Chinese mother/child pairs serving as a surrogate of maternal and fetal glycemia. Differential ultrasound examination of the fetal's body (head circumference, biparietal diameter, pectoral diameter, abdominal circumference, and femur length) was done in average 1 week prior to delivery. Multivariable regression analysis considering gestational age at delivery, the child's sex, maternal BMI, maternal age at delivery, maternal body weight, and pregnancy-induced hypertension revealed that fetal GSP was inversely associated with birth weight (R² = 0.416; P < 0.001). Fetal GSP was furthermore positively associated with the head-to-abdominal circumference ratio, whereas the maternal GSP was negatively correlated with the offspring's head-to-abdominal circumference ratio (R² = 0.285; P = 0.010 and R² = 0.261; P = 0.020, respectively). The increased head-to-abdominal circumference ratio in newborns with higher fetal GSP is mainly due to a reduced abdominal circumference rather than reduced growth of the brain.

CONCLUSION

The disproportional intrauterine growth is in line with the concept of so-called brain sparing, a mechanism maintaining the intrauterine growth of the brain at the expense of trunk growth. Our data suggest that the low birth weight phenotype, linked to cardiovascular diseases like hypertension in later life, might be a phenotype of disproportional intrauterine growth retardation and early life insulin resistance.

Venous liver blood flow and regulation of human fetal growth: evidence from macrosomic fetuses

OBJECTIVE

Experimental studies show that fetal liver venous perfusion is a determinant for growth in utero. Here we explore the relationship between fetal venous blood flow to the liver and macrosomia.

STUDY DESIGN

From diameter and blood flow velocity measurements, we derived liver venous blood flow in a longitudinal ultrasound study of 25 macrosomic fetuses of nondiabetic mothers during the second half of pregnancy.

RESULTS

Compared with appropriately growing fetuses, macrosomic fetuses directed more umbilical blood to the liver tissue, with correspondingly less contribution from the portal circulation when normalized for fetal weight. Whereas total venous liver blood flow showed no late gestation rise in the reference population, it continued to increase in macrosomic fetuses and was accompanied by greater fetal weight.

CONCLUSION

The direct relationship between venous liver blood flow and macrosomia in the fetus supports the concept that intrauterine growth is linked to the amount and distributional pattern of venous liver perfusion.

Insulin and the IGF system in the human placenta of normal and diabetic pregnancies

The insulin/insulin-like growth factor (IGF) system regulates fetal and placental growth and development. In maternal diabetes, components of this system including insulin, IGF1, IGF2 and various IGF-binding proteins are deregulated in the maternal or fetal circulation, or in the placenta. The placenta expresses considerable amounts of insulin and IGF1 receptors at distinct locations on both placental surfaces. This makes the insulin and the IGF1 receptor accessible to fetal and/or maternal insulin, IGF1 and IGF2. Unlike the receptor for IGF1, the insulin receptor undergoes a gestational change in expression site from the trophoblast at the beginning of pregnancy to the endothelium at term. Insulin and IGFs are implicated in the receptor-mediated regulation of placental growth and transport, trophoblast invasion and placental angiogenesis. The dysregulation of the growth factors and their receptors may be involved in placental and fetal changes observed in diabetes, i.e. enhanced placental and fetal growth, placental hypervascularization and higher levels of fetal plasma amino acids.

Mutations in the glucokinase gene of the fetus result in reduced placental weight

OBJECTIVE

In human pregnancy, placental weight is strongly associated with birth weight. It is uncertain whether there is regulation of the placenta by the fetus or vice versa. We aimed to test the hypothesis that placental growth is mediated, either directly or indirectly, by fetal insulin.

RESEARCH DESIGN AND METHODS

Birth weight and placental weight were measured in 43 offspring of 21 parents with mutations in the glucokinase (GCK) gene (25 had inherited the mutation and 18 had not), which results in reduced fetal insulin secretion. Birth weight, placental weight, umbilical cord insulin, and maternal glucose and insulin concentrations were measured in 573 nondiabetic, healthy, term pregnancies.

RESULTS

GCK mutation carriers were lighter and also had smaller placentas (610 vs. 720 g, P = 0.042). This difference was also seen in 17 discordant sibling pairs (600 vs. 720 g, P = 0.003). GCK mRNA was not detected in the placenta by RT-PCR. In the normal pregnancies, placental weight was strongly correlated with birth weight (r = 0.61, P < 0.001). Cord insulin concentrations were directly related to placental weight (r = 0.28) and birth weight (r = 0.36) (P < 0.001 for both).

CONCLUSIONS

These results suggest that insulin, directly or indirectly, plays a role in placental growth, especially as a mutation in the GCK gene, which is known to only alter fetal insulin secretion, results in altered placental weight. This finding is consistent with the preferential localization of the insulin receptors in the fetal endothelium of the placenta in the last trimester of pregnancy.

Maternal vitamin D status during pregnancy and child outcomes

OBJECTIVE

To investigate whether exposure to high maternal concentrations of 25(OH)-vitamin D in pregnancy poses any risk to the child.

DESIGN

Prospective study.

SETTING

Princess Anne Maternity Hospital, Southampton, UK.

SUBJECTS

A group of 596 pregnant women were recruited. A total of 466 (78%) children were examined at birth, 440 (74%) at age 9 months and 178 (30%) at age 9 years.

METHODS

Maternal 25 (OH)-vitamin D concentrations were measured in late pregnancy. Anthropometry of the child was recorded at birth, 9 months and 9 years. At 9 months, atopic eczema was assessed. At 9 years, children had an echocardiogram and a dual energy x-ray absorptiometry scan, blood pressure, arterial compliance and carotid intima-media thickness were measured and intelligence and psychological function assessed.

RESULTS

There were no associations between maternal 25(OH)-vitamin D concentrations and the child's body size or measures of the child's intelligence, psychological health or cardiovascular system. Children whose mothers had a 25(OH)-vitamin D concentration in pregnancy >75 nmol/l had an increased risk of eczema on examination at 9 months (OR 3.26, 95% CI 1.15-9.29, P=0.025) and asthma at age 9 years (OR 5.40, 95% CI, 1.09-26.65, P=0.038) compared to children whose mothers had a concentration of <30 nmol/l.

CONCLUSION

Exposure to maternal concentrations of 25(OH)-vitamin D in pregnancy in excess of 75 nmol/l does not appear to influence the child's intelligence, psychological health or cardiovascular system; there could be an increased risk of atopic disorders, but this needs confirmation in other studies.

Increased insulin sensitivity and maintenance of glucose utilization rates in fetal sheep with placental insufficiency and intrauterine growth restriction

In this study we determined body weight-specific fetal (umbilical) glucose uptake (UGU), utilization (GUR), and production rates (GPR) and insulin action in intrauterine growth-restricted (IUGR) fetal sheep. During basal conditions, UGU from the placenta was 33% lower in IUGR fetuses, but GUR was not different between IUGR and control fetuses. The difference between glucose utilization and UGU rates in the IUGR fetuses demonstrated the presence and rate of fetal GPR (41% of GUR). The mRNA concentrations of the gluconeogenic enzymes glucose-6-phophatase and PEPCK were higher in the livers of IUGR fetuses, perhaps in response to CREB activation, as phosphorylated CREB/total CREB was increased 4.2-fold. A hyperglycemic clamp resulted in similar rates of glucose uptake and utilization in IUGR and control fetuses. The nearly identical GURs in IUGR and control fetuses at both basal and high glucose concentrations occurred at mean plasma insulin concentrations in the IUGR fetuses that were approximately 70% lower than controls, indicating increased insulin sensitivity. Furthermore, under basal conditions, hepatic glycogen content was similar, skeletal muscle glycogen was increased 2.2-fold, the fraction of fetal GUR that was oxidized was 32% lower, and GLUT1 and GLUT4 concentrations in liver and skeletal muscle were the same in IUGR fetuses compared with controls. These results indicate that insulin-responsive fetal tissues (liver and skeletal muscle) adapt to the hypoglycemic-hypoinsulinemic IUGR environment with mechanisms that promote glucose utilization, particularly for glucose storage, including increased insulin action, glucose production, shunting of glucose utilization to glycogen production, and maintenance of glucose transporter concentrations.

Impact of fetal growth restriction on body composition and hormonal status at birth in infants of small and appropriate weight for gestational age

BACKGROUND

Fetal growth restriction (FGR) has been related to several health risks, which have been generally identified in small-for-gestational age (SGA) individuals.

OBJECTIVE

To evaluate the impact of FGR on body composition and hormonal status in infants born either small- or appropriate-for-gestational age (AGA).

METHODS

Fetal growth was assessed by ultrasound every 4 weeks from mid-gestation to birth in 248 high-risk pregnancies for SGA. Fetal growth velocity was calculated as change in the estimated fetal weight percentiles and FGR defined as its reduction by more than 20 percentiles from 22 gestational weeks to birth. Impact of FGR on body composition, cord insulin, IGF-I, IGF binding protein-3 (IGFBP-3), and cortisol concentrations was assessed in SGA and AGA newborns.

RESULTS

Growth-retarded AGA infants showed significantly reduced birth weight, ponderal index, percentage of fat mass, and bone mineral density when compared with AGA newborns with stable intrauterine growth. Cord IGF-I and IGFBP-3 concentrations were significantly decreased in growth-retarded infants in both SGA and AGA groups. Cord insulin concentration was significantly lower and cord cortisol significantly higher in AGA infants with FGR versus AGA newborns with stable intrauterine growth. After adjustment for gestational age and gender, birth weight was directly related to fetal growth velocity and cord IGF-I concentration. The variation in infant's adiposity was best explained by fetal growth velocity and cord insulin concentration.

CONCLUSIONS

FGR affects body composition and hormonal parameters in newborns with birth weight within the normal range, suggesting these individuals could be at similar metabolic risks as SGA. .

Measurement of cord insulin and insulin-related peptides suggests that girls are more insulin resistant than boys at birth

OBJECTIVE

We aimed to examine sex differences in insulin and insulin propeptide concentrations at birth using validated cord blood collection.

RESEARCH DESIGN AND METHODS

We tested the impact on insulin and insulin propeptides of taking 13 cord blood samples in heparin and EDTA and then centrifuging and separating plasma after 1, 2, 24, or 48 h at room temperature (heparin) or 4 degrees C (EDTA). Cord plasma insulin and insulin propeptides concentrations were measured in 440 babies and correlated with offspring anthropometry measured at birth.

RESULTS

Cord insulin concentrations significantly decreased (74% those at baseline by 24 h; P = 0.01) in the samples taken in heparin and stored at room temperature, but those taken on EDTA and refrigerated remained stable for up to 48 h. Insulin propeptides were stable in both. Cord plasma insulin and insulin propeptides measured in EDTA were related to all measures of birth size and maternal glycemia and BMI (r > 0.11; P < 0.03 for all) and were higher in those delivered via caesarean section. Girls were lighter (3,497 vs. 3,608 g; P = 0.01) but had higher cord insulin (46.7 vs. 41.2 pmol/l; P = 0.031), total proinsulin (34.1 vs. 25.8 pmol/l; P < 0.001), and intact proinsulin (9.5 vs. 8.3 pmol/l; P = 0.004) concentrations than boys; this was further confirmed when cord insulin concentrations of boys and girls were compared after pair matching for birth weight (insulin 49.7 vs. 42.1 pmol/l; P = 0.004).

CONCLUSIONS

When using appropriate sample collection methods, female newborns have higher insulin concentrations than male newborns, despite being smaller, suggesting intrinsic insulin resistance in girls.

Placental immaturity and hyperinsulinaemia in full-term newborns

BACKGROUND

Evidence from large studies suggests that low birthweight is a risk factor for cardiovascular disease and glucose metabolism disorders in adulthood, but the physiological mechanisms involved in intrauterine growth conditioning low birthweight are not completely understood. The objectives of this study were to determine whether placental immaturity (PI), defined as the lower quartile of placental maturity index (PMI), is associated to hyperinsulinaemia at birth and to identify the risk factors associated with PI.

MATERIALS AND METHODS

Cross-sectional study conducted at medical research units of two Mexican general hospitals. A total of 272 full-term newborns with gestational age >/= 38 and < 41 weeks were allocated into the corresponding group according to the quartile distribution of PMI. Data from the lower (PMI < 13.3) and higher quartile (PMI >/= 24.3) were compared. The PMI was estimated by dividing the number of epithelial plates by the average thickness of the epithelial plate. Serum measures included cord glucose and insulin levels of the newborns at birth.

RESULTS

A total of 74 (27.2%) children had hyperinsulinaemia at birth, of them 47 (63.5%) with PI. The adjusted multiple regression analysis showed a strong association between PI and hyperinsulinaemia at birth [odds ratio (OR) 2.6; CI 95% 1.3-4.3). Additional adjusted analysis showed that both mother's age </= 16 years (OR 1.75; CI95% 1.2-9.1) and maternal cigarette smoking (OR 2.7; CI95% 1.3-8.9) are associated to PI.

CONCLUSIONS

The PI is independently associated with hyperinsulinaemia at birth: smoking and mother's age lower than 16 years are risk factors for development of PI.

Weight deficit at birth and Turner's syndrome

Turner's syndrome (TS) is one of the most frequent diseases accompanied by growth deficiency. Though developmental disorders have been observed in the fetal period, there has been disagreement as to whether short stature is frequent in newborn girls with Turner's syndrome. Hence we attempted to determine the incidence of 'small for gestational age' in TS compared with healthy newborns girls delivered at term above -2 SD (body length and weight) for gestational age. The medical records of 548 girls with TS recruited from Polish university and district hospitals were screened, with 468 of them delivered at term (gestational age > or =38 weeks) being included in this study. Mean weight (+/- SD) at birth was 2963 +/- 444 g, which was below the normal value for gestational age in nearly 90%. The mean birth weight deficiency was 600 g, but exceeded 1000 g in over 10%. When a newborn girl delivered at term has a marked weight deficit, Turner's syndrome should be considered. This is especially so when the girl is a product of a first pregnancy, when routine karyotyping is recommended. The condition may arise from a partial dysfunction of a gene or genes on the X-chromosome involved in the control of fetal growth.

The gender insulin hypothesis: why girls are born lighter than boys, and the implications for insulin resistance

Girls are born lighter than boys. The consistency of this observation across different populations is striking, suggesting that it may have fundamental significance for those conditions linked with lower birth weight, such as diabetes. Previous hypotheses relating low birth weight to subsequent diabetes have addressed differences in insulin resistance within the sexes, not between them. Here, we propose that gender-specific genes affecting insulin sensitivity are responsible for the gender difference in birth weight--the genetically more insulin resistant female fetus is less responsive to the trophic effects of insulin and is therefore smaller. These genes also render female subjects more susceptible to diabetes, explaining why reports of type 2 diabetes (T2D) in younger populations show a female preponderance. Consistent with our proposal, concentrations of insulin and/or its propeptides are higher at birth in female populations and they are intrinsically more insulin resistant throughout life, with attendant impact on their metabolism, and the regressions describing the relationship between insulin resistance and adiposity in female and male subjects have similar gradients, but different constants. These gender-specific genes have a demonstrable impact on fetal growth and insulin resistance. Diabetes and cardiovascular disease are thought to be driven by insulin resistance, and the observations reported here may help to focus the search for genes that control it.

Paternal insulin resistance and its association with umbilical cord insulin concentrations

AIMS/HYPOTHESIS

Fetal growth is influenced by genetic factors as well as the intra-uterine environment. We hypothesised that some genetic factors may alter fetal insulin secretion and insulin action.

SUBJECTS, MATERIALS AND METHODS

To assess this, we analysed plasma insulin concentration in umbilical cord blood from 644 normal, term, UK Caucasian deliveries from the Exeter Family Study of Childhood Health. We tested for associations between cord insulin and each of parental anthropometry, fasting glucose, insulin and lipids.

RESULTS

As expected, cord insulin concentrations correlated with all measures of birth size (weight, length, head and arm circumferences, sum of skinfold thicknesses, ponderal index: r=0.16-0.4, p<0.01 for all) and maternal BMI (r=0.11, p=0.005), maternal glucose (r=0.25, p<0.001) and maternal insulin resistance (r=0.23, p<0.001). Paternal fasting insulin and insulin resistance were correlated with cord insulin (r=0.15, p=0.006; r=0.13, p=0.001, respectively), and this was independent of paternal BMI. Multiple linear regression analysis revealed paternal insulin resistance to be a predictor of cord insulin concentrations, independently of maternal factors.

CONCLUSION

Our results show an independent relationship between paternal insulin resistance and cord insulin concentrations. This is consistent with heritability of insulin resistance from father to offspring and a compensatory increase in fetal insulin secretion, the latter occurring pre-natally before the homeostatic feedback loop between glucose and insulin is established.

Geographical variation in neonatal phenotype

BACKGROUND

Recent studies have shown associations between size and body proportions at birth and health outcomes throughout the life cycle, but there are few data on how neonatal phenotype varies in different populations around the world.

METHODS

Data from the UK, Finland, India, Sri Lanka, China, DR Congo, Nigeria, and Jamaica (n=22,067) were used to characterize geographical differences in phenotype in singleton, live-born newborns. Measurements included birth weight, placental weight, length, head, chest, abdominal and arm circumferences, and skinfolds.

RESULTS

Neonates in Europe were the largest, followed by Jamaica, East Asia (China), then Africa and South Asia. Birth weight varied widely (mean values 2,730-3,570 g), but in contrast, head circumference was similar in all except China (markedly smaller). The main difference in body proportions between populations was the head to length ratio, with small heads relative to length in China and large heads relative to length in South Asia and Africa.

CONCLUSIONS

These marked geographical differences in neonatal phenotype need to be considered when investigating determinants of fetal growth, and optimal phenotype for short-term and long-term outcomes.

Geographical variation in relationships between parental body size and offspring phenotype at birth

BACKGROUND

Size and body proportions at birth are partly determined by maternal body composition, but most studies of mother-baby relationships have only considered the effects of maternal height and weight on offspring birth weight, and few have examined the size of effects. Paternal size and body composition also play a role, primarily through the fetal genome, although few studies have investigated relationships with neonatal phenotype.

METHODS

Data from the UK, Finland, India, Sri Lanka, China, DR Congo, Nigeria and Jamaica were used to investigate the effects of maternal measures (derived at 30 weeks' gestation, n=16,418), and also paternal size (n=3,733) on neonatal phenotype, for singleton, live-born, term births.

RESULTS

After accounting for variation in maternal size and shape across populations, differences in neonatal phenotype were markedly reduced. Mother-baby relationships were similar across populations, although some were stronger in developing countries. Maternal height was generally the strongest predictor of neonatal length, maternal head circumference of neonatal head and maternal skinfold thickness of neonatal skinfolds. Relationships with maternal arm muscle area were generally weak. Effects of paternal height and body mass index were weaker than the equivalent maternal measurements in most studies.

CONCLUSIONS

Differences in maternal body composition account for a large part of the geographical variation in neonatal phenotype. The size of the effects of all maternal measures on neonatal phenotype suggests that nutrition at every stage of the mother's life cycle may influence fetal growth. Further research is needed into father-baby relationships and the genetic mechanisms that influence fetal growth.

Increased neonatal fat mass, not lean body mass, is associated with maternal obesity

OBJECTIVE

The purpose of this study was to compare body composition measures in neonates of women who were overweight/obese (body mass index, > or = 25 kg/m2) versus women who were lean/average (body mass index, < 25 kg/m2), all of whom had normal glucose tolerance levels.

STUDY DESIGN

Seventy-six neonates (34 female and 42 male) of singleton pregnancies of pregravid overweight/obese women and 144 neonates (67 female and 77 male) of lean/average women were assessed with anthropometric measures and total body electrical conductivity evaluation of body composition at birth.

RESULTS

There was a borderline increase in birthweight (3436 +/- 567 g vs 3284 +/- 534 g; P = .051) but not lean body mass (3020 +/- 410 g vs 2950 +/- 400 g; P = .23) in the overweight/obese versus lean/average weight groups. However, there were significant increases in percent body fat (11.6% +/- 4.7% vs 9.7 +/- 4.3%; P = .003) and fat mass (420 +/- 220 g vs 380 +/- 170 g; P = .01) in neonates of overweight/obese women versus lean/average weight women.

CONCLUSION

Overweight/obese women with normal glucose tolerance levels have neonates who are heavier than lean/average weight women because of increased adiposity. We speculate that this increased obesity in offspring of obese women with normal glucose tolerance levels is a significant risk for adolescent obesity and components of the metabolic syndrome.

Metabolic risk in early childhood: the EarlyBird Study

OBJECTIVE

For a decade or more, poor nutrition during gestation, expressed as low weight at birth, was held to be the factor responsible for insulin resistance later in life. Birth weights, however, are rising and insulin-resistant states, such as diabetes, faster still. Alternative explanations are needed for insulin resistance in contemporary society. This review cites data from the EarlyBird study on the relationships of insulin resistance and metabolic disturbance in early childhood.

DESIGN

EarlyBird is a nonintervention prospective cohort study that asks the question 'Which children develop insulin resistance, and why?' It is unique in taking serial blood samples from a young age with which to monitor the behaviour of insulin resistance and its metabolic correlates, and in its comprehensive assessment of factors known or thought to influence insulin resistance

SUBJECTS

In all, 307 randomly selected healthy school children at school entry (mean age 4.9 y) and at 12 and 24 months later.

MEASUREMENTS

In the children: Birth weight and, at each time point height, weight, body mass index (BMI, kg/m(2)), skinfolds at five sites, circumferences, resting energy expenditure, physical activity, body composition, heart rate variability, diet, HOMA-IR and HOMA-ISC, blood pressure, full blood count, haemoglobin and haematocrit, HbA1C, total cholesterol, HDL cholesterol, LDL cholesterol, triglycerides, uric acid, IGF-1, gonadotrophins and SHBG. In their parents: At baseline height, weight, BMI, waist circumference, HOMA-IR and HOMA-ISC, full blood count, haematocrit, HbA1C, total cholesterol, HDL cholesterol, calculated LDL cholesterol, triglycerides, uric acid, gonadotrophins and SHBG.

RESULTS

Four observations are reported here: (1) There are clear correlations in contemporary children between insulin resistance and weight at 5 y, but none with birth weight. (2) Females throughout life are intrinsically more insulin resistant than males. (3) The substantial variation of physical activity among young children is attributable to the child, and not to his environment. (4) There is dissociation in young children between fatness and insulin resistance.

CONCLUSION

There is much yet to be learned about the development of obesity and insulin resistance in children. The notions of overnutrition and underactivity alone are too simplistic.

Diminished beta-cell replication contributes to reduced beta-cell mass in fetal sheep with intrauterine growth restriction

Human fetuses with severe intrauterine growth restriction (IUGR) have less pancreatic endocrine tissue and exhibit beta-cell dysfunction, which may limit beta-cell function in later life and contribute to their increased incidence of noninsulin-dependent diabetes mellitus. Three factors, replication, apoptosis, and neoformation, contribute to fetal beta-cell mass. We studied an ovine model of IUGR to understand whether nutrient deficits lead to decreased rates of fetal pancreatic beta-cell replication, increased rates of apoptosis, or lower rates of differentiation. At 90% of term gestation, IUGR fetal and pancreatic weights were 58% and 59% less than pair-fed control, respectively. We identified a selective impairment of beta-cell mass compared with other pancreatic cell types in IUGR fetuses. Insulin and insulin mRNA contents were less than other pancreatic endocrine hormones in IUGR fetuses, as were pancreatic insulin positive area (42%) and beta-cell mass (76%). Pancreatic beta-cell apoptosis was not different between treatments. beta-cell capacity for cell cycling, determined by proliferating cell nuclear antigen (PCNA) immunostaining, was not different between treatment groups. However, the percentage of beta-cells actually undergoing mitosis was 72% lower in IUGR fetuses. These results indicate that in utero nutrient deficits decrease the population of pancreatic beta-cells by lengthening G1, S, and G2 stages of interphase and decreasing mitosis near term. Diminished beta-cell mass in IUGR infants at birth, if not adequately compensated for after birth, may contribute to insufficient insulin production in later life and, thus, a predisposition to noninsulin-dependent diabetes.

Neonatal bone mass: influence of parental birthweight, maternal smoking, body composition, and activity during pregnancy

Evidence is accumulating that intrauterine growth and development may influence an individual's risk of osteoporosis in later adult life. To examine maternal and paternal influences on intrauterine skeletal growth, we used dual-energy X-ray absorptiometry to measure the neonatal bone mineral content (BMC) and bone mineral density (BMD) of 145 infants born at term. Independently of the infant's duration of gestation at birth, the birthweights of both parents and the height of the father were positively correlated with neonatal whole body BMC. Women who smoked during pregnancy had infants with a lower whole body BMC and BMD; overall, there was a 7.1-g (11%) average difference between whole body BMC of infants whose mothers did and did not smoke during pregnancy (p = 0.005). Women with thinner triceps skinfold thicknesses (reflecting lower fat stores) and those who reported a faster walking pace and more frequent vigorous activity in late pregnancy also tended to have infants with a lower BMC and BMD (p values for BMC; 0.02, 0.03, and 0.05, respectively). Maternal thinness and faster walking pace but not maternal smoking or parental birthweight also were associated with lower bone mineral apparent density (BMAD). The influences on skeletal growth and mineralization were independent of placental weight, a marker of the placental capacity to deliver nutrients to the fetus. These observations point to a combination of genetic and intrauterine environmental influences on prenatal skeletal development and suggest that environmental modulation, even at this early stage of life, may reduce the risk of osteoporosis in adulthood.

Early-life programming of susceptibility to dysregulation of glucose metabolism and the development of Type 2 diabetes mellitus

There is increasing epidemiological evidence in humans which associates low birthweight with later metabolic disorders, including insulin resistance and glucose intolerance. There is evidence that nutritional and hormonal factors (e.g. maternal protein restriction, exposure to excess maternal glucocorticoids) markedly influence intra-uterine growth and development. A picture is also emerging of the biochemical and physiological mechanisms that may underlie these effects. This review focuses on recent research directed towards understanding the molecular basis of the relationship between indices of poor early growth and the subsequent development of glucose intolerance and Type 2 diabetes mellitus using animal models that attempt to recreate the process of programming via an adverse intra-uterine or neonatal environment. Emphasis is on the chain of events and potential mechanisms by which adverse adaptations affect pancreatic-beta-cell insulin secretion and the sensitivity to insulin of key metabolic processes, including hepatic glucose production, skeletal-muscle glucose disposal and adipose-tissue lipolysis. Unravelling the molecular details involved in metabolic programming may provide new insights into the pathogenesis of impaired glucoregulation and Type 2 diabetes.

Observational study of maternal anthropometry and fetal insulin

AIMS

To examine the relation between maternal body fat and fetal metabolism.

METHODS

In this observational study, cord blood samples were collected from 60 infants of healthy women for the measurement of insulin and C peptide concentrations. Maternal weight, height, body mass index (BMI) and body composition (skinfold thickness measurements and bioelectrical impedance) were assessed at 13-15 weeks of gestation. Twenty five of the volunteers agreed to have a 75 g oral glucose tolerance test at 28-31 weeks of gestation.

RESULTS

Positive correlations were observed with both cord insulin or C peptide concentrations and maternal early pregnancy BMI (r=0.44, p=0.002 and r=0.33, p=0.008, respectively). There was no significant correlation between cord insulin or C peptide concentrations and birthweight or birth weight centiles.

CONCLUSION

Maternal BMI could be a predictor of fetal cord insulin concentration.

Relationship between maternal serum vascular endothelial growth factor concentration in early pregnancy and fetal and placental growth

Vascular endothelial growth factor (VEGF) has important effects on endothelial cells increasing cell proliferation, permeability and nitric oxide production; concentrations of VEGF in the maternal serum increase during the first 10 weeks of pregnancy. In this study, the relationship of maternal serum VEGF with maternal health during pregnancy and with fetal and placental size at mid-pregnancy and at term was investigated. Serum was obtained from 539 Caucasian women with singleton pregnancies between 8 and 20 weeks of pregnancy (mean 14 weeks). Total serum VEGF concentrations were measured by direct competitive radioimmunoassay. Fetal size and placental volume were measured by ultrasound between 16 and 20 weeks gestation. Birthweight, placental weight and anthropometric measurements of the baby were obtained after delivery. Serum VEGF concentrations were found to be higher in women with a lower weight before pregnancy (P = 0.01) and in those carrying a female fetus (P = 0.002). VEGF concentrations were positively correlated with placental volume (r = 0.17, P = 0.0001) but not with fetal size between 16 and 20 weeks gestation. Serum VEGF concentrations were positively correlated with both birthweight (r = 0.10, P = 0.02) and placental weight at delivery (r = 0.13, P = 0.003). The data presented support the view that VEGF may be one of the factors involved in mediating the maternal cardiovascular adaptation to pregnancy.

Maternal regulation of fetal development and health in adult life

Babies who are small or disproportionate at birth, or who have altered placental growth are now known to have increased rates of coronary heart disease, hypertension and non-insulin-dependent diabetes in adult life. These associations are thought to result from fetal 'programming', whereby a stimulus or insult at a critical, sensitive period of early life has permanent effects on the body's structure, physiology and metabolism. Small size at birth and disproportion in head size, length and weight appear to be surrogate markers for the actual influences that programme the fetus. These observations have prompted a re-evaluation of the maternal regulation of human fetal development. Recent studies suggest that the fetus may be considerably more sensitive to the materno-placental supply of nutrients than hitherto imagined. Adult cardiovascular disease may be a consequence of fetal adaptations invoked when the materno-placental nutrient supply fails to match the fetal nutrient demand. Understanding the maternal regulation of human fetal development could lead to public health measures that improve the adult health of future generations.

Disproportionate fetal growth and fingerprint patterns

Fingerprint whorl patterns are formed during fetal life. In a group of 180 term infants, those with more fingerprint whorls tended to have a small abdominal circumference (P = 0.09) and high ratio of head to abdominal circumference (P = 0.008). These associations were independent of the relation between the whorl counts of the mothers and their infants. We also found an independent correlation between the babies' whorl count and the combination of increasing subscapular (P = 0.03) and decreasing triceps (P = 0.02) skinfold thicknesses of the mothers. Whorl patterns are associated with adult hypertension; maternal nutritional status may influence their common origin during fetal development.