Macrosomia revisited: ponderal index and leptin delineate subtypes of fetal overgrowth

Adipokines in pregnancy

Reproductive success consists of a sequential events chronology, starting with the ovum fertilization, implantation of the embryo, placentation, and cellular processes like proliferation, apoptosis, angiogenesis, endocrinology, or metabolic changes, which taken together finally conduct the birth of healthy offspring. Currently, many factors are known that affect the regulation and proper maintenance of pregnancy in humans, domestic animals, or rodents. Among the determinants of reproductive success should be distinguished: the maternal microenvironment, genes, and proteins as well as numerous pregnancy hormones that regulate the most important processes and ensure organism homeostasis. It is well known that white adipose tissue, as the largest endocrine gland in our body, participates in the synthesis and secretion of numerous hormones belonging to the adipokine family, which also may regulate the course of pregnancy. Unfortunately, overweight and obesity lead to the expansion of adipose tissue in the body, and its excess in both women and animals contributes to changes in the synthesis and release of adipokines, which in turn translates into dramatic changes during pregnancy, including those taking place in the organ that is crucial for the proper progress of pregnancy, i.e. the placenta. In this chapter, we are summarizing the current knowledge about levels of adipokines and their role in the placenta, taking into account the physiological and pathological conditions of pregnancy, e.g. gestational diabetes mellitus, preeclampsia, or intrauterine growth restriction in humans, domestic animals, and rodents.

Birth size after embryo cryopreservation: larger by all measures?

STUDY QUESTION

Are the changes in birthweight after frozen and fresh embryo transfer associated with corresponding changes in other measures of foetal growth and placental efficiency?

SUMMARY ANSWER

Although placental efficiency was reduced for both frozen and fresh embryo transfer, children born after frozen embryo transfer (frozen-ET) had symmetrically increased size at birth, whereas children born after fresh embryo transfer (fresh-ET) were asymmetrically smaller at birth, compared to naturally conceived children.

WHAT IS KNOWN ALREADY

In pregnancies following frozen-ET, the risk of being born large, as measured by birthweight, is higher than after natural and fresh-ET conceptions. It is not known whether this is a result of symmetrically increased growth and increased placental efficiency.

STUDY DESIGN, SIZE, DURATION

A Norwegian nationwide registry-based cohort study of 3093 singletons born after frozen-ET, 15 510 singletons born after fresh-ET and 1 125 366 singletons born after natural conception from 1988 to 2015 was performed. We identified 6334 sibships with at least two different conception methods.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Data were collected from the Medical Birth Registry of Norway and the Norwegian National Education Database. Main outcome measures were birth length, birthweight, head circumference, ponderal index (birthweight relative to birth length in kg/m3), placental weight, birthweight:placental weight ratio, gestational age, and birthweight z-score. We estimated mean differences between children born after frozen-ET and fresh-ET compared to natural conception, at the population level and within sibships. Adjustments were made for birth year, maternal age, parity, and education.

MAIN RESULTS AND THE ROLE OF CHANCE

Estimates at the population level and within sibships were consistent for all outcomes, for both fresh and frozen-ET compared to natural conception. Within sibships, children born after frozen-ET had longer mean length (Δ = 0.42 cm, 95% CI 0.29 to 0.55) and head circumference (Δ = 0.32 cm, 95% CI 0.23 to 0.41) at birth, but a similar ponderal index (Δ = 0.11 kg/m3, 95% CI -0.04 to 0.26), compared to naturally conceived. Children born after fresh-ET had a shorter length (Δ = -0.22 cm, 95% CI -0.29 to -0.15) and head circumference (Δ = -0.15 cm, 95% CI -0.19 to -0.10), and lower ponderal index (Δ = -0.15 kg/m3, 95% CI -0.23 to -0.07) at birth compared to natural conception within sibships. Furthermore, mean placental weight was larger after both frozen-ET (Δ = 37 g, 95% CI 28 to 45) and fresh-ET (Δ = 7 g, 95% CI 2 to 13) compared to natural conception within sibships, whereas mean birthweight:placental weight ratio was reduced for both frozen-ET (Δ = -0.11, 95% CI -0.17 to -0.05) and fresh-ET (Δ = -0.13, 95% CI -0.16 to -0.09). A range of sensitivity analyses all gave similar conclusions as the main models, including restriction to full siblings, restriction to single embryo transfer, and adjustment for maternal BMI, height, and smoking.

LIMITATIONS, REASONS FOR CAUTION

Additional adjustment for maternal BMI, height, and smoking was possible only for a small sample of the study population (15%). Data on causes and duration of infertility, as well as treatment details, were limited.

WIDER IMPLICATIONS OF THE FINDINGS

The increased birthweight observed in singletons after frozen-ET is associated with a symmetrically increased birth size and large placentas, also after controlling for maternal factors through sibship analyses. Identifying the responsible treatment factors and the long-term health outcomes are particularly important considering the increase in elective freezing of all embryos.

STUDY FUNDING/COMPETING INTEREST(S)

This work was partly supported by the Central Norway Regional Health Authorities (project number 46045000), the Norwegian University of Science and Technology (project number 81850092) and the Research Council of Norway through its Centres of Excellence funding scheme (project number 262700). The authors have no conflicts of interest to declare.

TRIAL REGISTRATION NUMBER

N/A.

Fetal macrosomia, fetal insulin, and insulin-like growth factor- 1 among neonates in Lagos, Nigeria: A case-control study

Purpose

Fetal macrosomia is associated with perinatal injuries. The purpose of this study was to assess the relationship between fetal insulin, insulin-like Growth factor-1(IGF-1), and macrosomia in a resource-limited setting.

Method

This was a case-control study at tertiary and secondary health facilities in Lagos, Nigeria. One hundred and fifty mother-neonate pairs were recruited, and their socio-demographic and obstetric history was recorded. Fetal cord venous blood was collected at birth, and neonatal anthropometry was measured within 24hrs of life. Insulin and IGF-1 assay were measured with Enzyme-Linked Immunosorbent Assay (ELISA). Pearson’s Chi-square was used to assess the association between categorical variables and macrosomia. Spearman’s rank correlation of insulin, IGF-1, and fetal anthropometry was performed. Multivariable logistic regression was used to evaluate the association of insulin and IGF-1 with fetal birth weight. A statistically significant level was set at P-value < 0.05.

Results

Macrosomic neonates had mean fetal weight, fetal length, and occipitofrontal circumference (OFC) of 4.15±0.26kg, 50.85±2.09cm and 36.35± 1.22cm respectively. The median Insulin (P = 0.023) and IGF-1 (P < 0.0001) were significantly higher among macrosomic neonates as compared to normal weight babies. Maternal BMI at birth (p = 0.003), neonate’s gender (p < 0.001), fetal cord serum IGF-1 (p < 0.001) and insulin assay (P-value = 0.027) were significant predictors of fetal macrosomia. There was positive correlation between cord blood IGF-1 and birth weight (r = 0.47, P-value < 0.001), fetal length (r = 0.30, P-value = 0.0002) and OFC (r = 0.37, P-value < 0.001).

Conclusion

Among participating mother-neonate dyad, maternal BMI at birth, neonate’s gender, and fetal cord serum IGF-1 and serum insulin are significantly associated with fetal macrosomia.

Determinants of the persistency of macrosomia and shoulder dystocia despite treatment of gestational diabetes mellitus

Aims

to identify potentially modifiable risk factors associated with the persistency of macrosomia and/or shoulder dystocia in infants born to women treated for gestational diabetes mellitus (GDM).

Methods

this case-control retrospective study included 113 cases complicated by macrosomia (ponderal index ≥97^th percentile) and/or shoulder dystocia, and 226 controls without these complications. Factors associated with macrosomia and/or shoulder dystocia and with failure of diabetes management were assessed by multivariable analyses.

Results

Macrosomia and/or shoulder dystocia were associated with previous delivery of a large for gestational age (LGA) infant (adjusted odds ratio, 2.34, 95% confidence interval [1.01–5.45]), three abnormal glucose values during oral glucose tolerance test (2.83 [1.19–6.72]), a higher gestational weight gain before treatment (1.08 [1.01–1.15]), and failure of diabetes management (2.68 [1.32–5.45]). A non-Euro Caucasian origin (3.08 [1.37–6.93]), previous delivery of a LGA infant (3.21 [1.31–7.87]), institution of treatment after 32 weeks of gestation (3.92 [1.86–8.25]), and insulin therapy (2.91 [1.20–7.03]) were associated with failure of diabetes management.

Conclusions

supportive care in at risk women, limitation of weight gain in early pregnancy, shortened delay between diagnosis and treatment of GDM, and intensive insulin dosage adjustments might be means to improve the neonatal prognosis of GDM.

Impact of exercise during pregnancy on gestational weight gain and birth weight: an overview

OBJECTIVE

This article presents the state of knowledge related to the impact of exercise on gestational weight gain and birth weight.

TRANSCENDENCE OF BABY WEIGHT

Birth weight is an important indicator of intrauterine environment and maternal and newborn health. There are several factors that can affect birth weight including mother's pre-pregnancy Body Mass Index (BMI), gestational weight gain, Gestational Diabetes Mellitus (GDM), chronic diabetes and gestational age at birth.

IMPACT OF EXERCISE DURING PREGNANCY

Physical exercise has the potential to prevent excessive gestational weight gain, GDM and the potential complications associated with obesity during pregnancy. Therefore, women who regularly exercise during pregnancy are more likely to have an appropriate gestational weight gain and in turn, an appropriate birth weight infant, preventing being LGA without increasing risk of SGA, and this reduces risk factors for later life chronic disease development in the child including cardiovascular disease, obesity and diabetes.

RECOMMENDATIONS

It would be advisable to promote compliance with physical activity and exercise recommendations during pregnancy by using the specific resources to prescribe exercise to pregnant women without obstetric contraindications.

Markers of obesity and growth in preeclamptic and normotensive pregnant women

The objective of the study was to analyse leptin, IGF-1, Apo A, lipoproteins, haem oxygenase-1 (HO-1) in maternal sera and venous umbilical cord sera of newborn babies of 25 preeclamptics (group II), and 25 normotensive pregnant women (group I) as markers of obesity and growth in preeclamptic and normotensive pregnant women. Apo A I and II levels were estimated by competitive immunoassay using direct chemiluminiscence technology. Haem oxygenase-1 (HO-1), leptin and IGF-1 were analysed by ELISA. Maternal and cord blood levels of homocysteine, folic acid, lipid profile (namely, total cholesterol, triglycerides, LDL-C, VLDL-C and HDL-C), Haem oxygenase 1 were higher in preeclamptic women as compared to normotensive pregnant women. Serum and cord blood Apo A-I and Apo B, leptin levels, IGF-I were lower in preeclamptic women as compared to normotensive pregnant. The findings of high serum HO-1 levels in maternal and cord blood in preeclampsia supports the role of oxidative stress and excessive inflammatory response in the pathogenesis of preeclampsia. It seems likely that IGF-1 and leptin play a central role in controlling foetal growth. There is increasing evidence that the foundations of life-long health are, in part, laid in the uterus. Findings of present study suggest that alterations in biochemical markers of growth and obesity occur in mothers and foetuses and modifications of uterine environment can be of help to prevent future cardiovascular risk. Impact statement Preeclampsia has been reported to be associated with an increased risk of later life cardiovascular disease. However, information regarding how obesity increases the risk of preeclampsia is limited. Atherogenic milieu occurring during pregnancy persists into adulthood and foetal growth retardation is strongly associated with adult atherosclerosis. There is conflicting evidence regarding alterations of IGFs in preeclamptic pregnancies and deficit in circulating and cord blood IGF-1 levels in intrauterine growth restricted newborns and a correlation between IGF-1 levels and birth weight have been reported. Leptin is a predictor of cardiovascular risk independent of insulin resistance. Emerging evidence supports an important role for the haem oxygenase system (HO-1) in the maintenance of a healthy pregnancy, especially during pathological challenge. Conflicting data are available regarding HO-1, leptin and IGF -1 in preeclamptic mothers. The extent to which they mediate foetal growth and developmental abnormalities remains to be clarified. Serum IGF-1 levels were significantly decreased in preeclamptics and maternal IGF-1 showed a strong inverse correlation with leptin levels. High serum HO-1 levels in maternal and cord blood in preeclampsia were observed in the present study. Findings of the present study suggest that alterations in biochemical markers of growth and obesity occur in mothers and foetuses and modifications of the uterine environment can be of help to prevent future cardiovascular risk.

Epigenetics and early life origins of chronic noncommunicable diseases

In light of the increasing threats of chronic noncommunicable diseases in developing countries, the growing recognition of the early life origins of chronic disease, and innovative breakthroughs in biomedical research and technology, it is imperative that we harness cutting-edge data to improve health promotion and maintenance. It is well recognized that chronic diseases are complex traits affected by a wide range of environmental and genetic factors; however, the role of epigenetic factors, particularly with regard to early life origins, remains largely unexplored. Given the unique properties of the epigenome-functionality during critical time windows, such as the intrauterine period, heritability, and reversibility-enhancing our understanding of epigenetic mechanisms may offer new opportunities for the development of novel early prediction and prevention paradigms. This may present an unparalleled opportunity to offer maternal and child health professionals important tools with the translational value to predict, detect, and prevent disease at an early age, long before its clinical occurrence, and as such, break lifelong and transgenerational cycles of disease. In doing so, modern technology can be leveraged to make great contributions to population health, quality of life, and reducing the burdensome economic costs of noncommunicable diseases in developing countries.

Cord blood leptin levels of healthy neonates are associated with IFN-γ production by cord blood T-cells

Leptin is a hormone synthesized by adipocytes and other tissues, including the placenta, and it regulates food intake and energy expenditure, reproductive and immune functions. To investigate the role of leptin in neonatal immunity, we measured serum leptin and cytokine (IFN-γ, TNF-α, IL-2, IL-4, IL-10, IL-12) levels in the cord blood (cb) of 510 healthy neonates, 14 small for gestational age (SGA), 312 appropriately grown for gestational age (AGA) and 184 large for gestational age (LGA). Median serum leptin concentration in the whole sample was 11 ng/ml. In 11.2% neonates (1 SGA, 32 AGA, 24 LGA), leptin levels were >90th percentile (median 39 ng/ml). In 33.3% of those (3.72% of total sample) with the highest leptin levels (median 46 ng/ml), significantly elevated levels of serum IFN-γ were also found (mean 27.11 pg/ml, range 17.5-38.5 pg/ml). In neonates with leptin levels ∼50th percentile (median 12 ng/ml) or <10th percentile (median 1 ng/ml), serum IFN-γ levels were negligible. All other cytokines measured, were < the assays' detection limits. To investigate whether leptin can independently influence cytokine gene expression by cb T-cells and monocytes (Mc), we cultured cb T-cells or Mc, isolated from randomly selected AGA neonates or adult peripheral blood, with leptin. This resulted in upregulation of IL-2, IFN-γ and IL-4 gene expression in cb and adult T-cells and IL-10 expression mainly in cb-Mc. Significantly higher expression of IFN-γ occurred in female cb-T-cells cultured with leptin, compared with male cb-T-cells. In conclusion, the concurrent presence of high concentrations in both leptin and IFN-γ in cb of healthy infants, and leptin's ability to directly upregulate cytokine gene expression in cb T and Mc cells, indicate that abnormally high leptin levels can independently influence the immune system of healthy newborns, and may mediate gender differences in the development of a Th1 polarized immune response.

Absence of increase in carotid artery intima-media thickness in infants of diabetic mothers

OBJECTIVE

Infants of diabetic mothers (IDM) are considered as a risk group for atherosclerosis. Increased aortic intima-media thickness has been reported in IDM. The purpose of this study was to assess carotid artery intima-media thickness (CA-IMT), left ventricular mass index (LVMI) and atherosclerotic risk factors in IDM.

METHODS

Thirty IDM and 25 healthy controls were included in the study. Of these infants, 14 were appropriate-for-gestational age (AGA) and 16 were large-for-gestational age (LGA). CA-IMT and LVMI were obtained by M-mode echocardiographic examination. The relationship between parameters of atherosclerosis and echocardiographic measurements was assessed by Pearson's correlation analysis.

RESULTS

LVMI was higher in LGA IDM when compared to AGA IDM and controls. CA-IMT was not significantly different between the groups and was also not related to atherosclerotic risk factors. Serum lipid and insulin levels were higher in LGA IDM when compared with AGA IDM and controls. There were no correlations between CA-IMT, LVMI and atherosclerotic risk factors.

CONCLUSIONS

In contrast to previous reports indicating an increase in CA-IMT in IDM, no differences were found between IDM and controls in this study. Our results indicate that macrosomic IDM are prone to hypertrophic cardiomyopathy but not to atherosclerotic changes in the blood vessels.

Influence of maternal diabetes on serum leptinemic and insulinemic status of the offspring: a case study of selected patients in a tertiary care hospital in Bangladesh

INTRODUCTION

Leptin is now known to be an important hormone affecting intrauterine fetal growth. Since growth of fetus is also affected by the glycemic status of the mother. Serum leptin of infant is influenced by the maternal diabetic state. Investigation of cord blood leptin in babies of DM (Diabetes Mellitus) and GDM (Gestational Diabetes Mellitus) mothers (controlled blood glucose levels) may provide some indication about involvement of genetic factor in the development of leptin abnormalities in fetus.

AIM

The study was taken to investigate whether cord blood insulin, c-peptide and leptin levels correlate with birth weight in offspring of DM mother.

METHODS

Blood was drawn from umbilical cord of 30 babies from GDM mothers (GDM-babies), 45 babies from Type 2 DM Mothers (DM-babies), and 30 babies from ND (Nondiabetic) mothers (ND-babies) of term pregnancy. Weight, blood glucose, placenta, serum leptin and c-peptide of the babies were measured.

RESULTS

Birth weight of GDM and DM babies were significantly higher compared to ND-babies. Glucose level in GDM babies was significantly higher than ND and DM babies. Leptin levels in GDM babies were significantly higher than that of ND and DM babies. Serum c-peptide in GDM babies was significantly higher than DM and ND babies. However, there was no significant difference in leptin-glucose ratio among the three groups. Irrespective of degree of hyperglycemia leptin is a major determinant of fetal growth.

CONCLUSIONS

DM mother produces different insulinemic and leptinemic responses in the fetus indicating a possible genetic involvement.

Adiponectin: serum levels, promoter polymorphism, and associations with birth size and cardiometabolic outcome in young adults born large for gestational age

OBJECTIVE

To assess whether the -11391G>A polymorphism in the regulatory region of the adiponectin gene (ADIPOQ) is associated with birth size, postnatal growth, adiponectinemia, and cardiometabolic risk in adult life.

DESIGN

Case-control study nested within a prospective cohort of 2063 community subjects born in 1978/1979 and followed since birth to date.

METHODS

ADIPOQ -11391G>A genotype-phenotype associations were evaluated in 116 subjects born large for gestational age (LGA) and 392 gender-matched controls at birth (birth size), at 8-10 years (catch-down growth), and at 23-25 years of age (cardiometabolic profile).

RESULTS

The -11391A variant allele frequency was higher in LGA subjects (P=0.04). AA genotype was associated with augmented probability of being born LGA (odds ratio=4.14; 95% confidence interval: 1.16-16.7; P=0.03). This polymorphism was associated neither with body composition nor with postnatal growth pattern. At the age of 23-25 years, the -11391A variant allele was associated with higher serum adiponectin levels (GG: 10.7+/-6.2 versus GA: 12.2+/-6.5 versus AA: 14.2+/-6.8 microg/ml; P<0.01). Subjects born LGA presented higher body mass index (BMI; P=0.01), abdominal circumference (P=0.04), blood pressure (P=0.04), and homeostasis assessment model for insulin resistance (P=0.01) than adequate for gestational age. Symmetry at birth did not influence these variables. The occurrence of catch-down of weight was associated with lower BMI and abdominal circumference (P<0.001) at 23-25 years.

CONCLUSIONS

The -11391A ADIPOQ gene variant was associated with increased chance of being born LGA and with higher adiponectin levels in early adult life.

Leptin and its metabolic interactions: an update

Obesity results from an abnormal accumulation of fat in the white adipose tissue. Recent research utilizing genetic models of obesity in rodents has implicated a major role of leptin as a controller of obesity. Leptin is a 167-amino acid peptide hormone encoded by the obesity gene (ob), which is secreted by adipocytes and plays an important role in regulating food intake, energy expenditure and adiposity. Leptin receptors (OB-R) are expressed in the central nervous system mainly in afferent satiety centres of hypothalamus and in peripheral organs such as adipose tissues, skeletal muscles, pancreatic beta-cells and liver, thus indicating the autocrine and paracrine role of leptin in energy regulation. In human beings, a highly organized circadian pattern of leptin secretion is observed with peak levels in the midnight probably resulting from cumulative hyperinsulinemia of entire day. Leptin has a dual role in weight maintenance. Leptin reflects total body adipose tissue mass whereas in conditions of negative and positive energy balance, the dynamic changes in plasma leptin concentration function as a sensor of energy balance and influence the efferent energy regulation pathways. Many effects of leptin on metabolism are mediated by interaction with Insulin and also by synergistic action with cholecystokinin. Besides physiological roles, leptin may influence pathological conditions like obesity-associated atherosclerosis, oxidative stress and cancers. The purpose of the present review is to summarize the important aspects of the biology, actions, and regulation of leptin and to serve as an update of new information.

Fetal responses during placental malaria modify the risk of low birth weight

Inflammation during placental malaria (PM) is associated with low birth weight (LBW), especially during the first pregnancy, but the relative contribution of maternal or fetal factors that mediate this effect remains unclear and the role of gamma interferon (IFN-gamma) has been controversial. We examined the relationship of maternal and cord plasma levels of IFN-gamma, tumor necrosis factor alpha, interleukin-10, ferritin, and leptin to birth weight for Tanzanian women delivering in an area where there is a high rate of malaria transmission. The placental levels of inflammatory cytokines, including IFN-gamma, increased significantly during PM in primigravid and multigravid women but not in secundigravid women. PM also increased maternal peripheral levels of all inflammatory markers except IFN-gamma but had strikingly little effect on cord levels of these proteins. In a multivariate analysis, placental IFN-gamma was negatively associated (P = 0.01) and cord ferritin was positively associated (P < 0.0001) with birth weight in infected (PM-positive [PM+]) first-time mothers. This relationship was not observed in other mothers, consistent with the epidemiology of PM and disease. Cord leptin had a strong positive relationship with birth weight in offspring of PM-negative women (P = 0.02 to P < 0.0001) but not in offspring of PM+ women (all differences were not significant) in the three gravidity groups. The results confirmed that placental IFN-gamma is related to LBW due to PM during first pregnancies and suggest that fetal ferritin plays a protective role. Because fetal cells are a source of placental IFN-gamma and cord ferritin, the fetal response to PM may modify the risk of LBW.

Ghrelin, leptin, IGF-1, IGFBP-3, and insulin concentrations at birth: is there a relationship with fetal growth and neonatal anthropometry?

BACKGROUND

Insulin, growth hormone (GH), and growth factors (insulin-like growth factors [IGFs] and their binding proteins [IGFBPs]) are known to influence fetal growth and also the synthesis/secretion of the recently discovered hormones leptin and ghrelin.

METHODS

In 153 delivering mothers and their offspring at birth, we prospectively investigated the association between mothers' and babies' serum concentrations of ghrelin, leptin, insulin, IGF-1, and IGFBP-3 and neonatal anthropometric characteristics and the growth of the fetus. We also tried to put babies' serum glucose and GH measurements in this context.

RESULTS

Birth weight (BW), birth length, head circumference, and ponderal index (PI) were positively associated with cord IGF-1, IGFBP-3, and leptin and negatively associated with GH. BW was independently associated with maternal stature and prepartum weight, birth length with maternal stature, PI with maternal insulin and prepartum weight, and head circumference with maternal ghrelin. Compared with preterm infants whose development was appropriate for gestational age (AGA), preterm growth-restricted babies displayed alteration in GH-IGF axis (increased GH and low IGF-1 and IGFBP-3 concentrations), low leptin and glucose concentrations, and increased ghrelin concentrations. In large-for-gestational-age (LGA) babies, leptin, IGFBP-3, insulin, and glucose concentrations were significantly higher in asymmetric LGA newborns than in symmetric LGA and AGA newborns.

CONCLUSIONS

We found relationships between metabolic factors, fetal growth, and anthropometry. Intrauterine growth restriction involved alteration in the fetal GH-IGF axis, with relatively low leptin and glucose concentrations and increased ghrelin concentrations. Leptin, insulin, and IGFBP-3 delineated subtypes of fetal overgrowth.

Leptin in embryos from control and diabetic rats during organogenesis: a modulator of nitric oxide production and lipid homeostasis

BACKGROUND

Leptin is involved in many metabolic and reproductive events and its levels are altered by the diabetic pathology. In this study, leptin concentrations and leptin effects on both nitric oxide (NO) and lipid concentrations were investigated in embryos from control and diabetic rats.

METHODS

Diabetes was induced by neonatal streptozotocin administration (90 mg/kg). Embryos from control and diabetic rats were obtained on days 10.5 and 13.5 of gestation, corresponding to early organogenesis and post-placentation periods respectively. Leptin was analysed by enzyme immunoanalysis and immunohistochemistry. Nitrates and nitrites were assessed as an index of NO production. Lipid concentrations were analysed by thin layer chromatography.

RESULTS

Leptin concentrations were decreased in embryos obtained from diabetic rats on days 10.5 and 13.5 of gestation when compared to controls. NO concentrations, elevated in diabetic embryopathy, were diminished in the presence of leptin in the embryos obtained from control and diabetic animals both during early organogenesis and after placentation. Leptin additions reduced phospholipid, cholesterol and cholesteryl ester concentrations in embryos obtained from diabetic rats during early organogenesis, although no leptin effects on lipid concentrations were observed in control embryos at this developmental stage. In embryos obtained on day 13.5 of gestation leptin additions reduced cholesteryl ester concentrations in controls, and diminished cholesteryl ester, triglycerides and phospholipids in embryos from diabetic rats.

CONCLUSIONS

We demonstrated that leptin plays a role in the regulation of NO concentrations and lipid homeostasis during embryo organogenesis and that the diabetic environment causes a reduction of leptin concentrations in rat embryos.

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.

Leptine et grossesse: dogmes, questions et perspectives

Leptin has been primarily considered as a protein secreted by the adipocyte and a regulator of satiety and energy homeostasis. A role for leptin in pregnancy was later suggested as circulating levels of leptin are high in the pregnant woman and leptin is synthetized within the placenta. Placental leptin production is increased in various obstetrical conditions associated with alterations of fetal growth (diabetes, preeclampsia). Furthermore, umbilical leptin can be viewed as a biomarker of fetal adiposity. Our aim is to review the putative roles of leptin in pregnancy.

The known and unknown of leptin in pregnancy

Leptin, which was identified originally as an adipocyte-derived protein, was regarded for years as an exclusive regulator of satiety and energy homeostasis. A role for leptin in pregnancy was later suggested by the findings that plasma levels during gestation are greater than in nongravid individuals and that leptin is synthesized within the fetoplacental unit. Observational studies have established that leptin production is dysregulated in several pathologic stages of pregnancy in association with alterations of fetal growth. For example, an overproduction of leptin by the placenta in pregnancy with diabetes mellitus or hypertension is associated with maternal hyperleptinemia. Evidence is also accumulating that umbilical leptin levels can be viewed as a biomarker of fetal adiposity. Ten years after its discovery as a hormone, we review the known and unknowns of leptin in pregnancy with particular emphasis on its functions in health and disease. We aim to demonstrate that studies of leptin in pregnancy largely have contributed to insight into the mechanisms of leptin action, both as a hormone and as a cytokine.

Prenatal programming of postnatal obesity: fetal nutrition and the regulation of leptin synthesis and secretion before birth

Exposure to either an increased or decreased level of intrauterine nutrition can result in an increase in adiposity and in circulating leptin concentrations in later life. In animals such as the sheep and pig in which fat is deposited before birth, leptin is synthesised in fetal adipose tissue and is present in the fetal circulation throughout late gestation. In the sheep a moderate increase or decrease in the level of maternal nutrition does not alter fetal plasma leptin concentrations, but there is evidence that chronic fetal hyperglycaemia and hyperinsulinaemia increase fetal fat mass and leptin synthesis within fetal fat depots. Importantly, there is a positive relationship between the relative mass of the 'unilocular' component of fetal perirenal and interscapular adipose tissue and circulating fetal leptin concentrations in the sheep. Thus, as in the neonate and adult, circulating leptin concentrations may be a signal of fat mass in fetal life. There is also evidence that leptin can act to regulate the lipid storage, leptin synthetic capacity and potential thermogenic functions of fat before birth. Thus, leptin may act as a signal of energy supply and have a 'lipostatic' role before birth. Future studies are clearly required to determine whether the intrauterine and early postnatal nutrient environment programme the endocrine feedback loop between adipose tissue and the central and peripheral neuroendocrine systems that regulate energy balance, resulting in an enhanced risk of obesity in adult life.

Determinants of fetal growth

Fetal growth is the end product of a variety of genetic, maternal, fetal, and placental factors. Maternal size is a dominant determinant of birth weight. Specific nutrients and their availability modify the expression of genetically determined metabolic and transfer systems. Hormones and growth factors of maternal, fetal, and placental origin regulate nutrient transfer and fetal organ development. Fetal development is ultimately determined by dynamic interactions between all of these factors beginning prior to conception and proceeding to delivery.

Sonographic evaluation of fetal growth and body composition in women with different degrees of normal glucose metabolism

OBJECTIVE

To investigate the maternal demographic and metabolic factors contributing to the growth of fetal lean and fat body mass in women whose degree of glucose intolerance is less than that defining gestational diabetes in comparison with women with normal glucose metabolism.

RESEARCH DESIGN AND METHODS

Longitudinal sonographic examinations of 66 singleton fetuses without anomalies of nonobese mothers with abnormal oral glucose challenge test (GCT) results and without gestational diabetes (group 1) were compared with those of 123 singleton fetuses without anomalies of nonobese mothers with normal GCT values (group 2). Lean body mass measurements included head circumference, femur length, mid-upper arm, and mid-thigh central areas. Fat body mass measurements included the anterior abdominal wall thickness, the subscapular thickness, and the mid-upper arm and mid-thigh subcutaneous areas. All the women performed a 24-h glucose profile on the day preceding the ultrasound scan. Multivariate logistic regression analysis established best-fit equations for fetal sonographic measurements of fat and lean body mass. Independent variables included groups 1 and 2, maternal age, parity, prepregnancy BMI, gestational age, weight gain during pregnancy, fetal sex, and the following averaged 24-h profile maternal capillary blood glucose values: preprandial, 1-h postprandial, and 2-h postprandial.

RESULTS

No difference was found between the two groups with respect to fetal lean body mass parameters; the factors that contributed significantly and most frequently were gestational age and fetal sex (male). With respect to fetal fat body mass, all the measurements were significantly higher in group 1 than in group 2. In all instances, the significantly contributing factors were gestational age and maternal 1-h postprandial glucose values, whereas another frequent contributor was prepregnancy BMI.

CONCLUSIONS

Our study suggests the possibility of using sonographically determined fetal fat and lean mass measurements as indicators of body composition. The assessment of these parameters, achievable in a noninvasive and reproducible fashion in pregnancies complicated by glucose intolerance, might enable the real-time detection of fetal overgrowth and disproportion, thus opening the possibility of exploring interventions to limit fetal fat accretion, birth weight, and potential resulting morbidity.

Leptin stimulates the activity of the system A amino acid transporter in human placental villous fragments

The activity and expression of placental nutrient transporters are primary determinants for the supply of nutrients to the fetus, and these nutrients in turn regulate fetal growth. We developed an experimental system to assess amino acid uptake in single primary villous fragments to study hormonal regulation of the amino acid transporter system A in term human placenta. Validation of the method, using electron microscopy and studies of hormone production, indicated that fragments maintained ultrastructural and functional integrity for at least 3 h. The activity of system A was measured as the Na(+)-dependent uptake of methylaminoisobutyric acid (MeAIB), and the effect of 1 h incubation in various hormones was investigated. Uptake of MeAIB into villous fragments in the presence of Na(+) was linear up to at least 30 min. Insulin (300 ng/ml, n = 14) increased system A activity by 56% (P < 0.05). This effect was also present at insulin concentrations in the physiological range (+47% at 0.6 ng/ml, n = 10, P < 0.05). Leptin (500 ng/ml, n = 14) increased Na(+)-dependent MeAIB uptake by 37% (P < 0.05). System A activity increased in a concentration-dependent fashion in response to leptin (n = 10). However, neither epidermal GF (600 ng/ml), cortisol (340 ng/ml), nor GH (500 ng/ml) altered system A activity significantly (n = 14). We conclude that primary single isolated villous fragments can be used in studies of hormonal regulation of nutrient uptake into the syncytiotrophoblast. These data suggest that leptin regulates system A, a key amino acid transporter.

Predictive value of hormone measurements in maternal and fetal complications of pregnancy

Intrauterine tissues (placenta, amnion, chorion, decidua) express hormones and cytokines that play a decisive role in maternal-fetal physiological interactions. The excessive or deficient release of some placental hormones in association with gestational diseases may reflect an abnormal differentiation of the placenta, an impaired fetal metabolism, or an adaptive response of the feto-placental unit to adverse conditions. This review is focused on the applicability of hormone measurements in the risk assessment, early diagnosis, and management of pregnancies complicated by Down's syndrome, fetal growth restriction, preeclampsia, preterm delivery, and diabetes mellitus. Combined hormonal tests or the combination of hormones and ultrasound may achieve reasonable sensitivity, but research continues to simplify the screening programs without sacrificing their accuracy. Only in a few instances is there sufficient evidence to firmly recommend the routine use of hormone tests to predict maternal and fetal complications, but the judicious use of selected tests may enhance the sensitivity of the risk assessment based solely on clinical and ultrasound examination.

Risks of congenital anomalies in large for gestational age infants

OBJECTIVES

To evaluate the association between large for gestational age (LGA) and demographic and medical risk factors as well as specific types of congenital anomalies.

STUDY DESIGN

A retrospective, case-control study on 2,149,617 consecutive births was conducted. LGA was defined as 1.64 SD above the mean weight for gestational age, adjusted by sex and altitude. Risk factor frequency distributions were compared between LGA and normal birth weight neonates. Associations between LGA and 41 infants with isolated congenital anomalies were evaluated.

RESULTS

Of 31,897 neonates with congenital anomalies, 1800 were LGA. Five anomalies were associated with LGA: talipes calcaneovalgus, hydrocephaly, combined angiomatoses, hip subluxation, and non-brown-pigmented nevi. Multiparity, vaginal bleeding, diabetes, and delivery by cesarean section were more frequent in LGA than in appropriate for gestational age infants' mothers. Several maternal but no paternal factors were statistically associated with an increased risk for LGA infants.

CONCLUSIONS

The clinical observation that nevi are more commonly observed in LGA patients was supported. The higher frequencies of hip subluxation and talipes calcaneovalgus among LGA neonates reinforces their pathogenesis as deformations, whereas those of combined angiomatoses and hydrocephaly could reflect increased fluid or body mass.

Prospective function of placental leptin at maternal-fetal interface

Leptin is an endocrine and a growth factor which is important for regulation of body fat, feeding, and energy homeostasis. The anti-obesity function of leptin has been recently extended to reproduction, puberty and pregnancy as an endocrine signal to the hypothalamus. Leptin controls the functional integrity of the feto-placental unit thereby maintaining pregnancy by virtue of its immunomodulatory property via T lymphocytes or other proto-oncogenes. Dysregulation of autocrine/paracrine function of leptin at feto-placento-maternal interface may be implicated in the pathogenesis of recurrent miscarriage gestational diabetes, pre-eclampsia and intra-uterine fetal growth retardation including disturbance of fetal bone turnover. This review will focus on the role of leptin in normal and abnormal pregnancy and fetal growth.

[Placental leptin and pregnancy pathologies]

Leptin, the protein encoded by the Ob gene, is produced by the white adipose tissue and by the placenta during pregnancy. Placental leptin production makes a substantial contribution to maternal circulating levels during pregnancy which rapidly decrease and return to normal after delivery. Leptin has been detected in fetal plasma as early as week 18 of gestation, and umbilical leptin concentrations are closely related to birth weight. This has led to the hypothesis that fetal fat mass mainly determines fetal circulating leptin. Placental leptin production is increased in choriocarcinoma, preeclampsia and type 1 diabetes. Estrogens, hypoxia and insulin have been suggested as positive regulators of placental leptin production. Maternal leptinemia might act as a sensor of energy balance during pregnancy. The presence of both leptin and leptin receptors in the placenta suggests that leptin can act by autocrine or endocrine pathways in the human placenta. The roles of fetal leptin and consequences of increased placental leptin production in pathological pregnancies have yet to be elucidated.

Leptin in pregnancy

Leptin is a polypeptide hormone that aids in the regulation of body weight and energy homeostasis and is linked to a variety of reproductive processes in both animals and humans. Thus, leptin may help regulate ovarian development and steroidogenesis and serve as either a primary signal initiating puberty or as a permissive regulator of sexual maturation. Perhaps significantly, peripheral leptin concentrations, adjusted for adiposity, are dramatically higher in females than in males throughout life. During primate pregnancy, maternal levels that arise from adipose stores and perhaps the placenta increase with advancing gestational age. Proposed physiological roles for leptin in pregnancy include the regulation of conceptus growth and development, fetal/placental angiogenesis, embryonic hematopoiesis, and hormone biosynthesis within the maternal-fetoplacental unit. The specific localization of both leptin and its receptor in the syncytiotrophoblast implies autocrine and/or paracrine relationships in this endocrinologically active tissue. Interactions of leptin with mechanisms regulating pre-eclampsia and maternal diabetes have also been suggested. Collectively, therefore, reports suggest that a better understanding of the regulation of leptin and its role(s) throughout gestation may eventually impact those causes of human perinatal morbidity and mortality that are exacerbated by intrauterine growth retardation, macrosomia, placental insufficiency, or prematurity.