Leptin serum concentrations in healthy neonates within the first week of life: relation to insulin and growth hormone levels, skinfold thickness, body mass index and weight

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

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

Programming of metabolism by adipokines during development

The intrauterine and early postnatal periods represent key developmental stages in which an organism is highly susceptible to being permanently influenced by maternal factors and nutritional status. Strong evidence indicates that either undernutrition or overnutrition during development can predispose individuals to disease later in life, especially type 2 diabetes mellitus and obesity, a concept known as metabolic programming. Adipose tissue produces important signalling molecules that control energy and glucose homeostasis, including leptin and adiponectin. In addition to their well-characterized metabolic effects in adults, adipokines have been associated with metabolic programming by affecting different aspects of development. Therefore, alterations in the secretion or signalling of adipokines, caused by nutritional insults in early life, might lead to metabolic diseases in adulthood. This Review summarizes and discusses the potential role of several adipokines in inducing metabolic programming through their effects during development. The identification of the endocrine factors that act in early life to permanently influence metabolism represents a key step in understanding the mechanisms behind metabolic programming. Thus, future strategies aiming to prevent and treat these metabolic diseases can be designed, taking into consideration the relationship between adipokines and the developmental origins of health and disease.

Bone Mass Accrual in First Six Months of Life: Impact of Maternal Diabetes, Infant Adiposity, and Cord Blood Adipokines

The perinatal period is a time of substantial bone mass accrual with many factors affecting long-term bone mineralization. Currently it is unclear what effect maternal gestational/type 2 diabetes has on infant bone mass accrual. This is a prospective study of offspring of Native American and Hispanic mothers with normoglycemia (n = 94) and gestational diabetes or type 2 diabetes (n = 64). Infant anthropometrics were measured at birth, 1, and 6 months of age. Cord blood leptin, high-molecular weight adiponectin (HMWA), pigment epithelium-derived factor (PEDF), vascular epithelium growth factor (VEGF), endoglin, and C-peptide were measured by ELISA. Infants had bone mineral density measurement at 1 month or/and 6 months of age using dual-energy x-ray absorptiometry scan. Mothers with diabetes were older (31 ± 6 years vs 25 ± 4 years) and had higher pre-pregnancy BMI (32.6 ± 5.8 vs 27.2 ± 6.4 kg/m²) than control mothers. Mean HbA1C of mothers with diabetes was 5.9 ± 1.0% compared to 5.1 ± 0.3% in controls early in pregnancy. Infants born to mothers with diabetes (DM-O) were born at a slightly lower gestational age compared to infants born to control mothers (Con-O). There was no difference in total body less head bone mineral content (BMC) or bone mineral density (BMD) between DM-O and Con-O. For both groups together, bone area, BMD, and BMC tracked over the first 6 months of life (r: 0.56, 0.38, and 0.48, respectively). Percent fat was strongly and positively correlated with BMC at 1 month of age (r = 0.44; p < 0.001) and BMC at both 1 and 6 months of age correlated strongly with birth weight. There were no associations between infant bone mass and cord blood leptin, PEDF, or VEGF, while C-peptide had a significant correlation with BMC at 1 and 6 months only in DM-O (p = 0.01 and 0.03, respectively). Infants born to mothers with well-controlled gestational/type 2 diabetes have normal bone mass accrual. Bone mineral content during this time is highly correlated with indices of infant growth and the association of bone mineral indices with percent body fat suggests that bone-fat crosstalk is operative early in life.

Ambient air pollution during pregnancy and cardiometabolic biomarkers in cord blood

Prenatal air pollution exposure has been associated with adverse childhood cardiometabolic outcomes. It is unknown whether evidence of metabolic disruption associated with air pollution is identifiable at birth. We examined exposure to prenatal ambient air pollution and cord blood cardiometabolic biomarkers among 812 mother-infant pairs in the Healthy Start study.

Placental lipid transport and content in response to maternal overweight and gestational diabetes mellitus in human term placenta

BACKGROUND AND AIMS

Placental lipid transport is altered in women with high prepregnancy body mass index (pre-BMI) or gestational diabetes (GDM), which consequently affects foetal growth. However, the interaction of maternal overweight (OW) and GDM on placental lipid metabolism and possible adaptations are less studied. We aimed to examine whether maternal OW or GDM is the main factor disrupting placental lipid processing in human term placenta.

METHODS AND RESULTS

A total of 152 lean (18.5 ≤ pre-BMI ≤ 23.9 kg/m²) and OW (24 ≤ pre-BMI ≤ 27.9 kg/m²) pregnant women with or without GDM with a scheduled delivery by caesarean section were recruited. Maternal venous blood samples were used to measure metabolic parameters during pregnancy. Term placentas and cord blood were collected at delivery to determine placental lipid metabolism and foetal circulating lipid levels. Maternal OW significantly increased the placental mRNA expression of genes involved in lipid metabolism (FAT/CD36, FATP1, FATP4, FATP6, and PPAR-α), elevated placental lipid content (triglyceride, cholesterol), enhanced placental mTORC1-rpS6 and ERK1/2 signalling, increased cord blood insulin levels and birth weight. Neonatal birth weight was positively correlated with maternal pre-BMI, placental ERK1/2 signalling and cord blood insulin. There was an interaction between OW and GDM in regulating key placental fuel transport and storage gene expression (LPL, FATP6, FABP7, PPAR-α, PPAR-β, PPAR-γ, IR-β, GLUT1, SNAT2, SNAT4, and LAT1).

CONCLUSION

Maternal OW mainly affects placental lipid metabolism, which may contribute to foetal overgrowth and may impact long-term offspring health. GDM plays a less significant role in affecting placental lipid transfer and other mechanisms may be involved.

The postnatal leptin surge in mice is variable in both time and intensity and reflects nutritional status

BACKGROUND/OBJECTIVES

The murine postnatal leptin surge occurs within the first 4 weeks of life and is critical for neuronal projection development within hypothalamic feeding circuits. Here we describe the influence of nutritional status on the timing and magnitude of the postnatal leptin surge in mice.

METHODS

Plasma leptin concentrations were measured 1-3 times per week for the first 4 weeks of life in C57BL/6J pups reared in litters adjusted to 3 (small), 7-8 (normal), or 11-12 (large) pups per dam fed breeder chow or raised in litters of 7-8 by dams fed high-fat diet (HFD) ad libitum starting either prior to conception or at parturition.

RESULTS

Mice raised in small litters become fatter than pups raised in either normal or large litters. The leptin surge in small litter pups starts earlier, lasts longer, and is dramatically larger in magnitude compared to normal litter pups, even when leptin concentrations are normalized to fat mass. In mice reared in large litters, weight gain is diminished and the surge is both significantly delayed and lower in magnitude compared to control pups. Pups reared by HFD-fed dams (starting preconception or at parturition) are fatter and have augmented leptin surge magnitude compared to pups suckled by chow-fed dams. Surge timing varies depending upon nutritional status of the pup; the source of the surge is primarily subcutaneous adipose tissue. At peak leptin surge, within each group, fat mass and plasma leptin are uncorrelated; in comparison with adults, pups overproduce leptin relative to fat mass. Plasma leptin elevation persists longer than previously described; at postnatal day 27 mice continue overproducing leptin relative to fat mass.

CONCLUSIONS

In mice, small litter size and maternal HFD feeding during the perinatal period augment the plasma leptin surge whereas large litter size is associated with a delayed surge of reduced magnitude.

The Role of Leptin in the Development of Energy Homeostatic Systems and the Maintenance of Body Weight

LEP is a pleiotropic gene and the actions of leptin extend well beyond simply acting as the signal of the size of adipose tissue stores originally proposed. This is a discussion of the multi-system interactions of leptin with the development of the neural systems regulating energy stores, and the subsequent maintenance of energy stores throughout the lifespan. The prenatal, perinatal, and later postnatal effects of leptin on systems regulating body energy stores and on the energy stores themselves are heavily influenced by the nutritional environment which leptin exposure occurs. This review discusses the prenatal and perinatal roles of leptin in establishing the neuronal circuitry and other systems relevant to the adiposity set-point (or “threshold”) and the role of leptin in maintaining weight homeostasis in adulthood. Therapeutic manipulation of the intrauterine environment, use of leptin sensitizing agents, and identification of specific cohorts who may be more responsive to leptin or other means of activating the leptin signaling pathway are ripe areas for future research.

Leptin Distribution in Rat Foetal and Extraembryonic Tissues in Late Gestation: A Physiological View of Amniotic Fluid Leptin

Prenatal leptin is key to regulating foetal growth and early metabolic programming. The presence of intact leptin in rat foetal (at late gestation) and neonatal (immediately after birth) stomach content and mucosa has been previously described, suggesting that it may act as a regulatory nutrient for the neonate rats, be internalised by the stomach, and play a physiological role early in life, which requires to be further investigated, including its origin. We aimed to study the ontogeny of the presence of leptin in the foetal stomach and key extraembryonic tissues in rats at late gestation (days 18-21). Leptin concentration was determined by enzyme-linked immunosorbent assay, and placental leptin immunolocalisation was analysed by immunohistochemistry. Leptin showed a sudden appearance in the amniotic fluid (AF) at day 20 of gestation, gastric content (swallowed AF), stomach, and umbilical cord, significantly increasing at day 21. Leptin levels in these fluids and tissues were positively correlated. In the placenta, leptin was detectable at all the studied days, but its localisation changed from widespread throughout the placenta at day 18 to well-defined in the labyrinth zone from day 19 onwards. The results support a possible internalisation of AF leptin by the immature stomach of near-term foetuses and suggest that changes in placental leptin localisation might help to explain the sudden appearance of leptin in AF at gestational day 20, with potential physiological significance regarding short-term feeding control and metabolic programming in the developing offspring.

An examination of sex differences in associations between cord blood adipokines and childhood adiposity

BACKGROUND

Though the physiological roles of adipokines in metabolism, insulin resistance and satiety are clear, literature regarding associations between cord blood adipokine levels and childhood adiposity is equivocal.

OBJECTIVES

To determine whether cord blood levels of leptin and adiponectin are associated with adiposity in children 2 to 5 years of age, and whether such associations are modified by sex.

METHODS

Leptin and adiponectin levels were measured in cord blood and anthropometric measures were completed on 550 children enrolled in the Maternal-Infant Research on Environmental Chemicals Child Development Plus study (MIREC-CD Plus). We used multivariable linear and Poisson regression models to determine associations between cord blood adipokine levels and child body mass index (BMI), triceps and subscapular skinfold thickness and risk of overweight/obesity and to assess effect modification by child sex.

RESULTS

Cord blood adiponectin was significantly associated with modest increases in BMI and the sum of triceps and subscapular skinfold z-scores in boys but not girls. A doubling of adiponectin levels was associated with a 30% increased risk of overweight/obesity in boys (RR = 1.30; 95% CI: 1.02, 1.64). Leptin was not associated with anthropometric measures in either sex.

CONCLUSIONS

The observed associations between adiponectin and adiposity in boys were statistically significant, of moderate magnitude, and underscore the value of considering sex-specific patterns.

BCG scar, socioeconomic and nutritional status: a study of newborns in urban area of Makassar, Indonesia

Objective

To investigate factors that determine the response to Bacille Calmette–Guérin (BCG) vaccination in urban environments with respect to socioeconomic status (SES), prenatal exposure to infections or newborn's nutritional status.

Methods

The study was conducted in an urban area, in Makassar, Indonesia. At baseline, 100 mother and newborns pair from high and low SES communities were included. Intestinal protozoa, soil transmitted helminths, total IgE, anti‐Hepatitis A Virus IgG and anti‐Toxoplasma IgG were measured to determine exposure to infections. Information on gestational age, birth weight/height and delivery status were collected. Weight‐for‐length z‐score, a proxy for newborns adiposity, was calculated. Leptin and adiponectin from cord sera were also measured. At 10 months of age, BCG scar size was measured from 59 infants. Statistical modelling was performed using multiple linear regression.

Results

Both SES and birth nutritional status shape the response towards BCG vaccination at 10 months of age. Infants born to low SES families have smaller BCG scar size compared to infants born from high SES families and total IgE contributed to the reduced scar size. On the other hand, infants born with better nutritional status were found to have bigger BCG scar size but this association was abolished by leptin levels at birth.

Conclusion

This study provides new insights into the importance of SES and leptin levels at birth on the development of BCG scar in 10 months old infants.

Altered maternal and placental lipid metabolism and fetal fat development in obesity: Current knowledge and advances in non-invasive assessment

Abnormal maternal lipid profiles, a hallmark of increased maternal adiposity, are associated with pregnancy complications such as preeclampsia and gestational diabetes, and offspring long-term metabolic health is impacted as the consequence of altered fetal growth, physiology and often iatrogenic prematurity. The metabolic changes associated with maternal obesity and/or the consumption of a high-fat diet effecting maternal lipid profiles and metabolism have also been documented to specifically affect placental function and may underlie changes in fetal development and life course disease risk. The placenta plays a critical role in mediating nutritional signals between the fetus and the mother. As obesity rates in women of reproductive age continue to increase, it is becoming evident that inclusion of new technologies that allow for a better understanding of early changes in placental lipid transport and metabolism, non-invasively in maternal circulation, maternal tissues, placenta, fetal circulation and fetal tissues are needed to aid timely clinical diagnosis and treatment for obesity-associated diseases. This review describes pregnancy lipid homeostasis, with specific reference to changes arising from altered maternal body composition on placental and fetal lipid transport and metabolism. Current technologies for lipid assessments, such as metabolomics and lipidomics may be impacted by labour or mode of delivery and are only reflective of a single time point. This review further addresses how established and novel technologies for assessing lipids and their metabolism non-invasively and during the course of pregnancy may guide future research into the effect of maternal metabolic health on pregnancy outcome, placenta and fetus.

Markers of bone metabolism, serum leptin levels and bone mineral density in preterm babies

The prospective study assessed the influence of serum leptin levels on markers of bone metabolism and bone mineral density in 2-year-old infants born preterm. A total of 57 randomized preterm Caucasian newborns (32nd-37th week of gestation) were included in the study. Bone metabolism markers were measured every 6 months. The infants were monitored prospectively up to the age of 2 years. When the infants turned 2 years of age, they were investigated by dual energy X-ray absorptiometry (lumbar spine). The median cord blood leptin levels was 3.07 μg/L. The median leptin level during check-ups before 2 years of age was 9.96 μg/L. The other laboratory markers were within the normal ranges for that age. The bone mineral density reached, on average, 0.410 g/cm2. Lower leptin levels in the cord blood and in the serum of preterm infants do not influence bone mineral density during the first 2 years of life.

Adipokines in umbilical cord blood from children born large for gestational age

BACKGROUND

The etiology of childhood obesity and the associated morbidity is multifactorial. Recently, data suggesting a prenatal programming towards later childhood obesity and metabolic deregulation through the intrauterine environment has emerged. This study explored the concentrations of adipokines and their mutual relationship at birth in children born to non-diabetic mothers.

METHODS

Adiponectin, leptin and sOB-R were measured using ELISA-based commercial kits in umbilical cord blood from 60 neonates (30 born large for gestational age [LGA] and 30 born appropriate for gestational age [AGA]). Children exposed to maternal diabetes, chronic disease and preeclampsia were excluded.

RESULTS

The LGA group exhibited significantly elevated concentrations of leptin (p<0.001) and of free leptin index (p<0.001) and decreased sOB-R concentrations (p=0.005) when compared to the AGA group, which persisted in multiple regression analysis after taking the gestational age into account (p=0.048, p<0.001 and p<0.001, respectively). Only a trend towards a difference in adiponectin was demonstrated (p=0.057) regardless of adjustment (p=0.150). However, the leptin/adiponectin ratio was elevated in the LGA group (p=0.008), regardless of adjustment (p=0.039).

CONCLUSION

The data indicate a disturbance of adipokines in macrosomic newborns and that the mutual ratios between adipokines may provide a more sensitive marker of metabolic disturbance than any isolated adipokine.

Leptin and neuropeptide Y levels in newborns

AIM

Several studies have investigated leptin and neuropeptide Y (NPY) levels in children, but the information for newborns in the literature is limited. The purpose of this study was to determine leptin and NPY levels in 14- to 28-day-old newborns.

MATERIALS AND METHODS

This prospective study was performed in Atatürk University Medical Faculty Research Hospital Neonatal Clinic, Erzurum, Turkey between July and December, 2014. Sixty-two 14- to 28-day-old neonates, 26 female and 36 male, were included. Age, height, and body weight of the patients were recorded. Feeding status was also recorded. The newborns were divided into two groups--those receiving breastfeeding only and those receiving breastfeeding and formula. Plasma leptin levels were measured using enzyme amplified sensitivity immunoassay (EASIA).

RESULTS

The mean leptin level in 14- to 28-day-old female neonates was 4.25 ± 3.08 ng/mL, and the mean NPY level was 24.79 ± 9.87 ng/mL. The mean leptin level in 14- to 28-day male neonates was 3.49 ± 2.52 ng/mL, and the mean NPY level was 25.80 ± 9.58 ng/mL. No significant difference was determined between leptin (p=0.228) or NPY (p=0.144) in terms of feeding status. No significant difference was also observed between the sex in terms of leptin or NPY levels (leptin p=0.775 and NPY p=0.687).

CONCLUSION

There were no differences in terms of feeding status and sex in leptin and NPY levels in the neonatal period.

Developmental influences on circuits programming susceptibility to obesity

Suboptimal maternal nutrition exerts lasting impacts on obesity risk in offspring, but the direction of the effect is determined by the timing of exposure. While maternal undernutrition in early pregnancy is associated with increased body mass index, in later pregnancy it can be protective. The importance of the timing of maternal undernutrition is also observed in rodents, however, many of the processes that occur in the last trimester of human gestation are delayed to the postnatal period. Neonatal leptin administration exerts lasting impacts on susceptibility to obesity in rodents. Although leptin can influence the formation of hypothalamic circuits involved in homeostatic control of feeding during the postnatal period, these effects are too late to account for its ability to reverse adverse metabolic programming due to early gestational exposure to maternal undernutrition. This review presents an alternative framework for understanding the effects of neonatal leptin through influences on developing thermoregulatory circuits.

Maternal obesity and the developmental programming of hypertension: a role for leptin

Mother-child cohort studies have established that both pre-pregnancy body mass index (BMI) and gestational weight gain are independently associated with cardio-metabolic risk factors in young adult offspring, including systolic and diastolic blood pressure. Animal models in sheep and non-human primates provide further evidence for the influence of maternal obesity on offspring cardiovascular function, whilst recent studies in rodents suggest that perinatal exposure to the metabolic milieu of maternal obesity may permanently change the central regulatory pathways involved in blood pressure regulation. Leptin plays an important role in the central control of appetite, is also involved in activation of efferent sympathetic pathways to both thermogenic and non-thermogenic tissues, such as the kidney, and is therefore implicated in obesity-related hypertension. Leptin is also thought to have a neurotrophic role in the development of the hypothalamus, and altered neonatal leptin profiles secondary to maternal obesity are associated with permanently altered hypothalamic structure and function. In rodent studies, maternal obesity confers persistent sympathoexcitatory hyper-responsiveness and hypertension acquired in the early stages of development. Experimental neonatal hyperleptinaemia in naive rat pups provides further evidence of heightened sympathetic tone and proof of principle that hyperleptinaemia during a critical window of hypothalamic development may directly lead to adulthood hypertension. Insight from these animal models raises the possibility that early-life exposure to leptin in humans may lead to early onset essential hypertension. Ongoing mother-child cohort and intervention studies in obese pregnant women provide a unique opportunity to address associations between maternal obesity and offspring cardiovascular function. The goal of the review is to highlight the potential importance of leptin in the developmental programming of hypertension in obese pregnancy.

Umbilical cord plasma and salivary insulin and leptin concentrations in AGA neonates: a preliminary report

Background and objective: Insulin and leptin hormones are important regulators of food intake and energy balance. There is limited information about insulin and leptin hormones in neonates. This preliminary study aimed to investigate the concentrations of insulin and leptin in umbilical cord plasma and neonate's saliva and their relationships.

METHODS

Umbilical cord plasma and salivary samples were obtained from 13 healthy, appropriate for gestational age (AGA) neonates. Insulin and leptin concentrations in umbilical cord plasma and saliva were measured using the MILLIPLEX MAP® Human Metabolic Hormone Magnetic Bead Panel.

RESULTS

Insulin concentrations in umbilical cord plasma correlates positively and significantly with leptin concentrations in umbilical cord plasma (r = 0.55, p = 0.04).

CONCLUSIONS

More research is needed to explore the relationships between insulin and leptin hormones in neonate's saliva.

Effect of reducing the n-6/n-3 fatty acid ratio on the maternal and fetal leptin axis in relation to infant body composition

OBJECTIVE

To investigate the effect of reducing the n-6/n-3 fatty acid ratio in maternal nutrition on the maternal and cord blood leptin axis and their association with infant body composition up to 2 years.

DESIGN AND METHODS

208 healthy pregnant women were randomized to either a dietary intervention to reduce the n-6/n-3 fatty acid ratio from 15th week of gestation until 4 months postpartum or a control group. Leptin, soluble leptin receptor and free leptin index were determined in maternal and cord plasma and related to infant body composition assessed by skinfold thicknesses up to 2 years.

RESULTS

The intervention had no effect on either the maternal or fetal leptin axis. Maternal leptin in late pregnancy was inversely related to infant weight and lean body mass (LBM) up to 2 years, after multiple adjustments. Cord leptin was positively related to weight, body fat, and LBM at birth, and inversely associated with weight, BMI, fat mass, and LBM at 2 years and weight gain up to 2 years. The contribution of cord leptin to infant outcomes was overall stronger compared with maternal leptin.

CONCLUSIONS

Both, maternal and fetal leptin were associated with subsequent infant anthropometry with a greater impact of fetal leptin.

Leptin and ghrelin levels in colostrum, milk and blood plasma of sows and pig neonates during the first week of lactation

Radioimmunology was used to determine leptin and ghrelin levels in sow colostrum and milk in relation to those in sow and neonatal pig blood plasma and to the body weight of piglets during the first week of lactation. The highest concentration of leptin was found in colostrum on the second day of lactation (69.3 ± 6.3 ng/mL). Leptin concentrations in sow plasma were significantly lower than in colostrum/milk (2.19 ± 0.9 ng/mL, P = 0.7692) and were stable in the first 7 days of lactation. Total and active ghrelin concentrations in colostrum/milk were stable in the measured time points (6734 ± 261 pg/mL, P = 0.3397; 831 ± 242 pg/mL, P = 0.3988, respectively). Total ghrelin concentrations in sow plasma were lower than in colostrum/milk. These results indicate that pigs follow a unique species-specific pattern of leptin and ghrelin synthesis, release and existence, and that the mammary gland is an important source of leptin and ghrelin contained in colostrum/milk.

Leptin and adiponectin in cord blood from children of normal weight, overweight and obese mothers

AIM

To study cord blood concentrations of adiponectin and leptin in children born by normal weight, overweight and obese mothers and to study these parameters in relation to a weight gain intervention programme for obese mothers.

METHODS

Ten millilitre cord blood was collected and analysed for leptin and adiponectin concentrations in children with gestational age >37 weeks born by 60 normal weight, 45 overweight and 145 obese mothers. 82 obese mothers took part in a weight gain intervention programme.

RESULTS

Concentrations of leptin and adiponectin were higher in cord blood from children of overweight and obese mothers compared with children of normal weight mothers (leptin: Md 13.2, 30, 3 and 90.2 ng/mL respectively, p < 0.001; adiponectin 35.9, 205.4, 213.8 ng/L p < 0.001). No differences were found between overweight and obese mothers. The weight gain intervention programme for obese pregnant women had significant effects on the weight gain during pregnancy but had no effects on cord blood serum concentrations of leptin and adiponectin.

CONCLUSION

Cord blood leptin and adiponectin concentrations were higher in children born by overweight or obese women compared with children of normal weight mothers. A weight gain intervention programme for obese pregnant women did not affect these results. Intrauterine exposition to high concentrations of leptin and adiponectin may play a role in weight development later in life.

In utero fuel homeostasis: Lessons for a clinician

Fetus exists in a complex, dynamic, and yet intriguing symbiosis with its mother as far as fuel metabolism is concerned. Though the dependence on maternal fuel is nearly complete to cater for its high requirement, the fetus is capable of some metabolism of its own. The first half of gestation is a period of maternal anabolism and storage whereas the second half results in exponential fetal growth where maternal stores are mobilized. Glucose is the primary substrate for energy production in the fetus though capable of utilizing alternate sources like lactate, ketoacids, amino acids, fatty acids, and glycogen as fuel under special circumstances. Key transporters like glucose transporters (GLUT) are responsible for preferential transfers, which are in turn regulated by complex interaction of maternal and fetal hormones. Amino acids are preferentially utilized for growth and essential fatty acids for development of brain and retina. Insulin, insulin like growth factors, glucagon, catecholamines, and letpin are the hormones implicated in this fascinating process. Hormonal regulation of metabolic substrate utilization and anabolism in the fetus is secondary to the supply of nutrient substrates. The knowledge of fuel homeostasis is crucial for a clinician caring for pregnant women and neonates to manage disorders of metabolism (diabetes), growth (intrauterine growth restriction), and transitional adaptation (hypoglycemia).

Lactation Biology Symposium: role of colostrum and colostrum components on glucose metabolism in neonatal calves

In neonatal calves, nutrient intake shifts from continuous glucose supply via the placenta to discontinuous colostrum and milk intake with lactose and fat as main energy sources. Calves are often born hypoglycemic and have to establish endogenous glucose production (eGP) and gluconeogenesis, because lactose intake by colostrum and milk does not meet glucose demands. Besides establishing a passive immunity, colostrum intake stimulates maturation and function of the neonatal gastrointestinal tract (GIT). Nutrients and nonnutritive factors, such as hormones and growth factors, which are present in high amounts in colostrum of first milking after parturition, affect intestinal growth and function and enhance the absorptive capacity of the GIT. Likely as a consequence of that, colostrum feeding improves the glucose status in neonatal calves by increasing glucose absorption, which results in elevated postprandial plasma glucose concentrations. Hepatic glycogen concentrations rise much greater when colostrum instead of a milk-based colostrum replacer (formula with same nutrient composition as colostrum but almost no biologically active substances, such as hormones and growth factors) is fed. In contrast, first-pass glucose uptake in the splanchnic tissue tended to be greater in calves fed formula. The greater plasma glucose rise and improved energy status in neonatal calves after colostrum intake lead to greater insulin secretion and accelerated stimulation of anabolic processes indicated by enhanced maturation of the postnatal somatotropic axis in neonatal calves. Hormones involved in stimulation of eGP, such as glucagon and cortisol, depend on neonatal diet, but their effects on eGP stimulation seem to be impaired. Although colostrum feeding affects systemic insulin, IGF-I, and leptin concentrations, evidence for systemic action of colostral insulin, IGF-I, and leptin in neonatal calves is weak. Studies so far indicate no absorption of insulin, IGF-I, and leptin from colostrum in neonatal calves, unlike in rodents where systemic effects of colostral leptin are demonstrated. Therefore, glucose availability in neonatal calves is promoted by perinatal maturation of eGP and colostrum intake. There may be long-lasting effects of an improved colostrum supply and glucose status on postnatal growth and development, and colostrum supply may contribute to neonatal programming of performance (milk and growth) in later life, but data proving this concept are missing.

Leptin levels in cord blood and anthropometric measures at birth: a systematic review and meta-analysis

The role of intrauterine environment in the development of obesity is increasingly recognised. Adipokines and specifically leptin have been examined as potential biomarkers predicting early development of obesity. We conducted a systematic review and meta-analysis of the epidemiological evidence for the association between leptin levels in cord blood and anthropometric measurements at birth in healthy mother-newborn pairs. A PubMed search was performed between 1994 and 2009 and manual search of reference lists of retrieved articles. Forty-four studies met the inclusion criteria set. All studies reported a positive correlation between leptin levels and birthweight. The combined correlation coefficient (r) was 0.46 [95%CI 0.43, 0.50]. Leptin levels explained 21% of variation in birthweight. Results were similar in males (r=0.55; 0.40, 0.68) and females (r=0.60; 0.50, 0.69), and between Caucasians (r=0.45; 0.39, 0.51) and eastern Asian populations (r=0.47; 0.37, 0.55). Statistically significant positive correlations were also found for birth length (r=0.29; 0.23, 0.34) and ponderal index (r=0.36; 0.31, 0.41). There was no indication of publication bias (Egger's test P-value=0.23). This meta-analysis shows a clear but moderate correlation between leptin levels in cord blood and birthweight that is observed in different population groups.

The conflicting effects of maternal nutrient restriction and early-life obesity on renal health

Epidemiological and animal studies have demonstrated that early-life nutrition alters the metabolic responses and generates structural changes in complex tissues, such as the kidneys, which may lead to a reduction in the offspring lifespan. Independently, obesity induces a spontaneous low-grade chronic inflammatory response by modulating several of the major metabolic pathways that ultimately compromise long-term renal health. However, the combined effects of maternal nutrition and early-life obesity in the development of renal diseases are far from conclusive. Previous results, using the ovine model, demonstrated that the combination of a reduction in fetal nutrition and juvenile obesity induced a series of adaptations associated with severe metabolic syndrome in the heart and adipose tissue. Surprisingly, exposure to an obesogenic environment in the kidney of those offspring produced an apparent reduction in glomerulosclerosis in relation to age- and weight-matched controls. However, this reduction in cellular apoptosis was accompanied by a rise in glomerular filtration rate and blood pressure of equal intensity when compared with obese controls. The intention of this review is to explain the adaptive responses observed in this model, based on insights into the mechanism of renal fetal programming, and their potential interactions with some of the metabolic changes produced by obesity.

The role of adipocytokines in fetal growth

Cumulative evidence suggests that the origins of obesity may occur during fetal development. In this respect, the concept of "developmental programming" was introduced and supported by experimental and epidemiological data. This concept supports the idea that the nutritional and hormonal status during pregnancy could irreversibly interfere in metabolism control. The mechanisms responsible for this developmental programming remain poorly documented. However, recent research indicates that adipocytokines may play a critical role in this process. Thus, leptin, adiponectin, and the recently identified resistin, visfatin, and apelin, all exert effects on fat, muscle, and liver cells early in life. The aforementioned adipocytokines are secreted by adipocytes and human placenta during fetal life and may play a major role in the etiopathogenesis of the metabolic syndrome. This review will focus on the intrauterine expression of adipocytokines, their contribution to the hormonal control of fetal growth, and their role in restricted and exaggerated intrauterine growth.

Association of cord plasma leptin with birth size in term newborns

BACKGROUND

Leptin is secreted from adipose tissue and plays an important role in obesity. Recent studies have shown that the relationship between Leptin and body fat mass may have ethnic differences. The purpose of our study was to investigate the relationship between venous umbilical cord plasma Leptin and anthropometric markers in term healthy Taiwanese newborns.

METHODS

Umbilical venous plasma samples were obtained from 98 term neonates (48 males and 50 females) and leptin Levels were analyzed by enzyme-linked immunosorbent assay.

RESULTS

Umbilical cord plasma Levels of leptin were significantly higher in the female neonates than in males (p<0.001). The large-for-gestationaL age and appropriate-for-gestational age newborns had significantly higher Leptin cord plasma levels than the small-for-gestational age newborns (p<0.01 and p<0.05, respectively). In both male and female neonates, umbilical Leptin Levels showed significant positive correlations with birth weight and birth Length. Multiple Linear regression analysis revealed that birth weight was the only significant predictor of umbilical cord plasma Leptin levels in both male and female neonates. However, the slopes of the regressions between Leptin and birth weight in male and female neonates were not different.

CONCLUSION

In Taiwanese healthy term neonates, leptin umbilical cord plasma Levels are associated with sex and birth weight of the neonate. The relationship between Leptin and birth weight may differ among different ethnic groups. These findings imply that the relationship between leptin and body fat mass may develop early in life.

Changes in insulin levels following 6-month treatment with recombinant human growth hormone in growth hormone-deficient adults

INTRODUCTION

Eighty-six adult patients with GH deficiency (GHD) of adult or childhood onset were treated for 6 months, with recombinant human growth hormone (rhGH) at a low (LD) or conventional dose (CD). The treatment effect on insulin levels was investigated.

METHODS

This manuscript refers to the Italian addendum to an International Study (B9R-EW-GDED) in which patients with GHD were randomized to receive r-hGH replacement therapy at a dose of either 3 microg/kg/day or 6 microg/kg/day for the 3 months. The dose was then doubled for the next 3 months.

RESULTS

After 6 months of r-hGH treatment, insulin levels increased with both GH dosages, with a greater increase achieved in the low-dose subgroup. Insulin levels also increased significantly in the childhood-onset, while even decreased in the adult-onset subgroup. On the whole, in more than 50% of patients, insulin values rose by >13%. Moreover, mean levels of IGF-I increased 2-3 fold (p<0.001 vs baseline) in both the LD and CD groups. Significant and similar increases in IGF binding protein-3 levels were seen in both the LD and CD groups over the treatment period, regardless the time of onset of GHD.

CONCLUSION

Insulin increased with both GH dosages and more than half of patients presented an important increase in insulin plasma levels. It would be of interest to assess if there is a correlation between the changes in insulin levels and other cardiovascular risk factors such as hemostatic parameters.

Cord blood leptin and adiponectin as predictors of adiposity in children at 3 years of age: a prospective cohort study

OBJECTIVES

Leptin and adiponectin are adipocyte-secreted hormones that regulate energy homeostasis and metabolism. Because their roles in the neonatal period and in early childhood are poorly understood, we aimed in this prospective cohort study to determine the extent to which umbilical cord blood leptin and adiponectin concentrations predict measures of adiposity and growth at 3 years of age.

PATIENTS AND METHODS

We studied 588 children participating in the prospective prebirth cohort study Project Viva. We examined associations of cord blood leptin and adiponectin levels with weight changes during the first 6 months of life, 3-year circulating leptin and adiponectin concentrations, and the following adiposity-related outcomes at 3 years of age: BMI z score, height-for-age z score, and sums of triceps and subscapular skinfold thicknesses to represent overall adiposity, as well as subscapular/triceps skinfold ratio to represent central adiposity.

RESULTS

Cord blood leptin and adiponectin were each directly associated with the duration of gestation and birth weight for gestational age z scores. Cord blood leptin levels were negatively associated with change in weight-for-length, weight-for-age, and length-for-age z scores between birth and 6 months of age. Similarly, cord blood adiponectin was negatively associated with change in weight-for-length and weight-for-age z scores. After adjusting for several maternal and child factors related to obesity, each 10 ng/mL increment of cord blood leptin was associated with a reduction in BMI z score and higher leptin levels at 3 years but not with skinfold thicknesses. Each 10 microg/mL increment of cord blood adiponectin was positively associated with a higher subscapular skinfold thickness/triceps skinfold thickness ratio at 3 years.

CONCLUSIONS

Lower cord blood leptin levels are associated with smaller size at birth but more pronounced weight gain in the first 6 months of life and higher BMI at 3 years of age. Cord blood adiponectin levels are also directly associated with birth weight for gestational age, inversely associated with weight gain in the first 6 months of life, and predict an increase in central adiposity at age 3 years.

Catch-up growth following fetal growth restriction promotes rapid restoration of fat mass but without metabolic consequences at one year of age

Background

Fetal growth restriction (FGR) followed by rapid weight gain during early life has been suggested to be the initial sequence promoting central adiposity and insulin resistance. However, the link between fetal and early postnatal growth and the associated anthropometric and metabolic changes have been poorly studied.

Methodology/Principal Findings

Over the first year of post-natal life, changes in body mass index, skinfold thickness and hormonal concentrations were prospectively monitored in 94 infants in whom the fetal growth velocity had previously been measured using a repeated standardized procedure of ultrasound fetal measurements. 45 infants, thinner at birth, had experienced previous FGR (FGR+) regardless of birth weight. Growth pattern in the first four months of life was characterized by greater change in BMI z-score in FGR+ (+1.26+/−1.2 vs +0.58 +/−1.17 SD in FGR−) resulting in the restoration of BMI and of fat mass to values similar to FGR−, independently of caloric intakes. Growth velocity after 4 months was similar and BMI z-score and fat mass remained similar at 12 months of age. At both time-points, fetal growth velocity was an independent predictor of fat mass in FGR+. At one year, fasting insulin levels were not different but leptin was significantly higher in the FGR+ (4.43+/−1.41 vs 2.63+/−1 ng/ml in FGR−).

Conclusion

Early catch-up growth is related to the fetal growth pattern itself, irrespective of birth weight, and is associated with higher insulin sensitivity and lower leptin levels after birth. Catch-up growth promotes the restoration of body size and fat stores without detrimental consequences at one year of age on body composition or metabolic profile. The higher leptin concentration at one year may reflect a positive energy balance in children who previously faced fetal growth restriction.

Adipocytes and adipose tissue

An epidemic of obesity is taking place in most societies around the world. Overall obesity substantially increases the risk of subsequent morbidity. In children and adolescents the degree of body fat mass depends upon ethnic background, gender, developmental stage and age. Obesity is characterized by increases in the number or size of fat cells, or a combination of both. It is generally believed that the number of fat cells depends on age of onset and degree of obesity. This chapter provides information on intrauterine growth of fetal adipose tissue, the earliest period of onset of proliferation, and some of the factors that interact to enhance or suppress development. Fetal adipose tissue development is regulated by the complex interaction of transcription factors, nutrients and adipocytokines. Maternal, endocrine, and paracrine factors also influence specific changes in angiogenesis, adipogenesis, and metabolism. During embryogenesis and in fetal life, leptin and adiponectin, two important adipocytokines, are present at high concentrations in the circulation and in tissues. Developmental stages and metabolic processes influenced by specific hormones and paracrine factors have been identified through examination of the offspring of obese and diabetic pregnancies, hormonal manipulation during late pregnancy in animal models, and the use of cell cultures. Collectively, the results of the studies cited herein delineate the basis for imprinting or conditioning of fetal pre-adipocytes at the paracrine/autocrine level, and of fetal adipose tissue development and metabolism.

Circulating apelin concentrations in mother/infant pairs at term

AIM

To prospectively investigate circulating concentrations of the adipokine and angiogenic factor apelin in mother/infant pairs and correlate them with respective insulin concentrations.

METHODS

Plasma apelin concentrations were determined in 40 mothers and their singleton full-term foetuses and neonates on day 1 (N1) and 4 (N4) of life.

RESULTS

Maternal apelin concentrations were lower compared to foetal, N1 and N4 ones (p<0.001 in all cases). N1 apelin concentrations were lower compared to foetal and N4 ones (p=0.002 and p=0.005, respectively). Maternal apelin concentrations positively correlated with foetal, N1 and N4 concentrations (r=0.663, p<0.001, r=0.486, p=0.003, r=0.484, p=0.003, respectively). Foetal apelin concentrations positively correlated with N1 and N4 ones (r=0.337, p=0.044 and r=0.574, p<0.001, respectively). N1 apelin concentrations positively correlated with N4 ones (r=0.513, p=0.001). No association was found between apelin concentrations and birthweight, gender, parity or mode of delivery. No significant correlations were observed between apelin and insulin concentrations.

CONCLUSIONS

Concentrations of apelin are high in the foetus, possibly suggesting its potential role in intrauterine development. Apelin expression in placental tissue could account for its higher foetal concentrations and for its down-regulation soon after birth. The postnatal increase of apelin concentrations could presumably point to a gradual initiation of ex utero angiogenesis.

Treatment of acromegaly with pegvisomant during pregnancy: maternal and fetal effects

OBJECTIVE

Our objective was to describe the first case of the successful use of pegvisomant during pregnancy in a woman with acromegaly.

DESIGN

We present the case of a 26-yr-old female with acromegaly who had failed surgical and subsequent medical therapy but whose disease was well controlled on pegvisomant. She then conceived and was continued on pegvisomant throughout pregnancy. We then collected both maternal and cord blood samples at parturition, and later analyzed her breast milk.

RESULTS

Maternal IGF-I was well controlled during gestation. Fetal GH and IGF-I were within the normal range. Maternal pegvisomant levels were consistent with a 25-mg daily dosage. Fetal pegvisomant levels were minimal and near the range detected in untreated acromegalic patients, likely representing minimal cross-reactivity from endogenous GH or spurious contamination by maternal blood. GH variant levels in the maternal blood and the cord blood were both within the normal ranges. Pegvisomant levels in breast milk were below the lower limit of quantification of the assay and similar to those observed when analyzing breast milk samples from normal mothers in the same assay. Fetal growth parameters were normal; the baby was healthy and showed no adverse signs.

CONCLUSIONS

Pegvisomant therapy during gestation was safe and effective in our patient. Transplacental passage of pegvisomant is either absent or minimal, with a concentration highly unlikely to convey any significant pharmacodynamic effects on the fetal GH and IGF-I system. In addition, there is no evidence of substantial secretion of pegvisomant into breast milk.

Blood visfatin concentrations in normal full-term pregnancies

AIM

To prospectively investigate blood visfatin concentrations during the perinatal period in normal pregnancies.

METHODS

Visfatin concentrations were determined in maternal, umbilical cord (representing the foetal state) and neonatal blood on day 1 (N1) and 4 (N4).

RESULTS

Maternal and foetal visfatin concentrations were similar (18.83+/-4.27 and 19.35+/-4.90 ng/mL, respectively). There were significant correlations between maternal and foetal (r=0.742, p<0.001), as well as between N1 and N4 (r=0.487, p=0.029) visfatin concentrations. Foetal concentrations were significantly elevated compared to N1 (p=0.032). There was no difference between N1 and N4 concentrations. However, there was a correlation between birth weight and neonatal visfatin concentrations: there was a mean increase in N1 and N4 visfatin concentrations by 0.221 ng/mL and 0.292 ng/mL, respectively, for every unit increase in customized centile (adjusted birth weight) (p=0.021 and p=0.005, respectively). No association was found between serum visfatin concentrations and gender, parity or mode of delivery.

CONCLUSIONS

Expression in foetal membranes and placental transfer could be responsible for higher blood visfatin concentrations during intrauterine life. Customized centiles seem to be independent predictor variables for postnatal visfatin concentrations. This finding could be attributed to the production of visfatin in adipose tissue, a main contributor to birth weight and consequently to customized centiles.

Body fat at birth and cord blood levels of insulin, adiponectin, leptin, and insulin-like growth factor-I in small-for-gestational-age infants

BACKGROUND

Low birthweight has been associated with an increased risk of obesity, insulin resistance, and diabetes in adulthood. The aim of this study was to evaluate IGF-I, adiponectin, insulin levels, and body fat in small-for-gestational-age (SGA) infants at birth.

METHODS

We performed a transverse comparative study in SGA and appropriate-for-gestational-age (AGA) infants. The study was conducted at the Hospital of Gynecology and Obstetrics in Leon, Mexico. Weight, length, and percent of body fat were evaluated during the first 48 h of birth. Glucose, insulin, leptin, adiponectin, and IGF-I levels in cord blood were measured.

RESULTS

We studied 100 infants (50 SGA and 50 AGA). A history of diabetes in a second-degree relative was higher in SGA infants than in AGA infants (48.0 vs. 30.0%, respectively; p = 0.03). Glucose, adiponectin, insulin and IGF-I levels were similar between the groups. Leptin levels and percentage of body fat were lower in SGA than AGA (15.3 vs. 23.4 ng/mL; p = 0.003, 11.1 vs. 12.7%; p <0.001, respectively). Logistic regression analysis showed that length, percentage of body fat, and leptin levels were positively associated with birthweight. However, leptin levels were not independent of percentage of body fat.

CONCLUSIONS

Low body fat and leptin levels, but no evidence of increased metabolic risk at birth, were found in SGA infants.

Hyperinsulinemia in cord blood in mothers with type 2 diabetes and gestational diabetes mellitus in New Zealand

OBJECTIVE

In genetically diabetes-prone populations, maternal diabetes during pregnancy increases the risk of their children developing diabetes and obesity (the vicious cycle of type 2 diabetes). Fetal hyperinsulinemia at birth acts as a marker of this risk. We therefore examined whether cord insulin and leptin concentrations are increased in offspring of Maori and Pacific Island mothers with type 2 and gestational diabetes mellitus (GDM) and varying degrees of glycemic control (HbA(1c)).

RESEARCH DESIGNS AND METHODS

Maori and Pacific Island mothers were prospectively recruited at Middlemore Hospital, South Auckland. Cord blood was taken from umbilical vein at birth from singleton babies born after 32 weeks of gestation to 138 mothers with GDM, 39 mothers with type 2 diabetes, and 95 control mothers.

RESULTS

Babies born to mothers with both type 2 diabetes and GDM had higher birth weight and skinfold thickness and markedly higher concentrations of insulin (median [interquartile range] type 2 diabetes 77 pmol/l [42-143], GDM 67 pmol/l [42-235], and control subjects 33 pmol/l [18-62]; P < 0.001) and leptin (type 2 diabetes 39 ng/ml [18-75], GDM 31 ng/ml [17-58], and control subjects 13 ng/ml [8-22]; P < 0.001) in cord blood. Cord insulin concentrations >120 pmol/l were found in 29% of offspring of mothers with GDM and 31% of mothers with type 2 diabetes. Many mothers with GDM had abnormalities of glucose tolerance postpartum (20% type 2 diabetes, 34% impaired glucose tolerance or impaired fasting glucose). Higher cord insulin (57 pmol/l [40-94]) and leptin (26 ng/ml [17-39]) concentrations were found even in offspring of GDM mothers with normal glucose tolerance postpartum.

CONCLUSIONS

Raised cord insulin and leptin concentrations are a common finding in offspring of mothers with type 2 diabetes and GDM in this population.

Inverse changes in the serum levels of the soluble leptin receptor and leptin in neonates: relations to anthropometric data

We aimed to evaluate the role of the soluble leptin receptor (sOB-R), the major leptin-binding protein in blood, for the regulation of growth and development of neonates. Therefore, human arterial and venous cord blood samples were taken from newborns of 45 healthy mothers to investigate correlations with anthropometric data. Furthermore, we compared changes in sOB-R and leptin in neonatal serum between postnatal d 1, 3, and 5. Cord blood levels of leptin (direct correlation) and the molar sOB-R/leptin ratio (inverse correlation) correlated significantly (P < 0.05) with weight, triceps, biceps, iliacal, and subscapular skinfolds at birth as well as on d 3 and 5 of life. During the first week of life, median leptin levels decreased significantly (P < 0.001) from 3.4 ng/ml in venous cord blood to 2.2 ng/ml in venous blood on d 1 after birth to 0.88 ng/ml on d 3 and 0.75 ng/ml on d 5. In contrast and most interestingly, median levels of sOB-R increased significantly (P < 0.001) from 14.5 ng/ml in cord blood to 18.9 ng/ml on d 1, 83 ng/ml on d 3, and 79.4 ng/ml on d 5. Consequently, the molar sOB-R/leptin ratio increased from 0.45 to 1.30 (d 1), 10.5 (d 3), and 13.7 (d 5) during the same period (P < 0.001). We found a remarkable postnatal change in the leptin-sOB-R axis with decreasing leptin and increasing sOB-R levels. Hence, the sOB-R may block leptin function by its competition with the membrane receptor for the ligand. These suppressive effects may be an important stimulus for energy uptake in the first week of life or in other conditions with a high energy demand.

Neonatal leptin levels are strongly associated with female gender, birth length, IGF-I levels and formula feeding

OBJECTIVE

To investigate predictors of circulating leptin in healthy full-term newborns and to explore the relationship with anthropometric variables, serum levels of adiponectin and the major components of the IGF system at birth. To explore whether leptin levels are regulated by breastfeeding vs. formula feeding.

DESIGN

Observational cross-sectional study.

PATIENTS

Three hundred and nineteen healthy full-term newborns delivered during 1999 in Athens, Greece.

MEASUREMENTS

Anthropometric measurements, formula feeding information and blood samples were obtained. Leptin and adiponectin determinations were performed using a radioimmunoassay (RIA).

RESULTS

Multivariate regression analyses showed that leptin levels were positively associated with female gender, newborn length, ponderal index and IGF-I levels, but not with adiponectin levels. Newborns who were fed exclusively with milk formulas had more than twice the leptin levels of those who were exclusively breastfed.

CONCLUSIONS

Leptin levels are positively related to female gender and anthropometric characteristics of neonates but, contrary to studies in adults, are not correlated with adiponectin levels. We also found evidence that formula feeding imparts a considerable increase in leptin levels in newborns.

Leptin profile in neonatal gonadotropin surge and relationship between leptin and body mass index in early infancy

AIM

This study was designed to investigate the longitudinal and dynamic profile of leptin and its relationship with sex hormones including luteinizing hormone (LH), follicle-stimulating hormone (FSH), estradiol (E2) and testosterone (TTE) in neonatal 'minipuberty'. We also investigated the effects of leptin in the regulation of body weight gain and body mass index (BMI) in the first 3 months of life.

METHODS

A longitudinal study was carried out in a cohort of 15 male and 15 female term infants during the first 3 months of life. Blood samples were collected in the morning from the infants on the 3rd, 15th, 30th, and 90th days of life. At each sample collection, anthropometric measurements were recorded. Serum leptin, LH, FSH, E2 (girls only) and TTE (boys only) concentrations were analyzed using standard biochemical methods. Association of leptin with weight gain, BMI, and these hormones during infancy was evaluated.

RESULTS

Leptin levels increased significantly between the 3rd and 90th days of life in both boys and girls. BMI of both groups increased significantly from the 3rd to the 90th day. There was no significant difference in the leptin levels and leptin/BMI ratios of the two sexes at different time points. Leptin levels on the 30th and 90th days correlated significantly with BMI in both sexes. LH and FSH levels in both groups were found to be significantly higher on the 15th day of life. No correlation was observed between leptin and LH, FSH, E2 or TTE levels throughout the study.

CONCLUSIONS

Leptin levels do not differ between the two sexes during early infancy and possibly there is no role for leptin in the surge of gonadotropins or sex steroids in neonatal minipuberty. The relationship between leptin and BMI could not be seen in the first postnatal days and the transient lack of the regulatory effect of BMI on leptin concentrations might reflect an adaptive resistance in the production of leptin to support catch-up growth after initial physiological weight loss in newborns.

The relation of insulin, leptin and IGF-1 to birthweight in offspring of women with type 1 diabetes

OBJECTIVE

Maternal diabetes is associated with excess foetal growth. We have assessed the influence of maternal diabetes on hormones associated with foetal growth and the relationship of these hormones to birthweight.

DESIGN

Case-control study.

PATIENTS

Singleton offspring of mothers with type 1 diabetes (ODM, n = 140) and control mothers (Control, n = 49).

MEASUREMENTS

Birthweight, cord blood insulin, proinsulin, 32-33 split proinsulin, leptin, IGF-1, IGFBP-3, cortisol.

RESULTS

Maternal diabetes was associated with higher birthweight (ODM 3.80 +/- 0.69 kg; Control; 3.56 +/- 0.52 kg, P = 0.02) and marked increases in insulin (median [interquartile range]: ODM 110 [60-217] pmol/l; Control 22 [15-37] pmol/l; P < 0.0001) and leptin (ODM 32 [15-60] ng/ml; Control 9 [4-17] ng/ml; P < 0.0001) but no absolute difference in IGF-1 (ODM 7.9 [6.2-9.8] nmol/l, Control 7.5 [6.2-9.8] nmol/l, P = 0.24) or its principle binding protein IGFBP-3 (ODM 1.63 +/- 0.38 micro g/ml, Control 1.63 +/- 0.28 micro g/ml; P = 0.12). Individually, insulin, insulin propeptides, leptin, IGF-1 and IGFBP-3 were significantly (P < 0.05) correlated with birthweight (in ODM and Control). IGF-1 and leptin were positively related to birthweight independently of each other and insulin in both ODM and Control. By contrast, insulin showed independent relationships to birthweight in ODM (P < 0.0001) but not in Control (P = 0.4).

CONCLUSIONS

Maternal diabetes is associated with marked elevation of insulin and leptin in cord blood of their offspring. Hormonal correlates of birthweight differ between ODM and Control with an independent relationship of insulin to birthweight observed only in ODM.

Cord plasma concentrations of adiponectin and leptin in healthy term neonates: positive correlation with birthweight and neonatal adiposity

OBJECTIVE

Adiponectin is negatively associated with leptin, insulin and obesity in children and adults. Whereas increases in fetal insulin and leptin are associated with increased weight and adiposity at birth, the role of adiponectin in fetal growth has not yet been determined. The aims of this study were to examine the relationships between adiponectin and insulin, leptin, weight and adiposity at birth in healthy term infants.

DESIGN AND METHODS

Anthropometric parameters including weight, length, circumferences and skinfold thickness were measured, and plasma lipid profiles, insulin, leptin and adiponectin concentrations in cord blood samples from 226 singleton infants born at term after uncomplicated pregnancies were assayed.

RESULTS

Cord plasma adiponectin, leptin and insulin levels correlated significantly and positively with birthweight (P = 0.001, P < 0.001, P < 0.001, respectively) and the sum of skinfold thicknesses (P < 0.001, P < 0.001, P < 0.001, respectively). Mean cord plasma adiponectin and leptin levels, but not insulin level, were significantly higher in large-for-gestational-age (LGA) infants compared with appropriate-for-gestational-age (AGA) infants. Cord plasma leptin concentration, but not adiponectin concentration, was significantly higher in female infants than in male infants (P = 0.003 and P = 0.94, respectively). Cord plasma adiponectin concentration correlated positively with leptin level (P = 0.007) but not with insulin level (P = 0.78).

CONCLUSIONS

High adiponectin levels are present in the cord blood. Cord plasma adiponectin and leptin levels are positively correlated with birthweight and adiposity. This suggests that adiponectin may be involved in regulating fetal growth.

Leptin levels as function of age, gender, auxological and hormonal parameters in 202 healthy neonates at birth and during the first month of life

Leptin signals to the brain energy stores and balance while integrating neuroendocrine functions. Leptin levels in adults are higher in females than in males, while a gender-related difference in newborns is controversial. To clarify this point, in 202 healthy neonates we measured dynamic changes in leptin levels over the first month of life and looked for correlation between leptin levels and auxological and hormonal parameters. Cord leptin concentration in females was higher (p < 0.001) than in males. IGF-I, IGF-II, insulin, testosterone and 17beta-estradiol levels were similar in both sexes while insulin-like growth factor binding protein 3 (IGF-BP3) levels in females were slightly higher than in males. Leptin levels were positively associated to body weight, gestational age, IGF-BP3 levels, insulin levels and maternal body mass index (BMI) at time of delivery. In a subset of subjects (no. = 65), in comparison with cord levels, serum leptin levels were decreased on the 5th day of life (p < 0.0001) and then increased at 1 month (p < 0.0001). Positive association between leptin and weight was lost on the 5th day of life but present again at 1 month. In conclusion, our findings in a large population of neonates definitely show that leptin levels at birth are functions of gender, body weight and gestational age but not of length, cranial circumference, IGF-I and IGF-II levels. These findings, coupled with weight-independent prompt decrease after birth followed by weight-dependent increase at one month of life, suggest that leptin secretion in neonates as well as in adults mainly signals the nutritional state to the brain.

Umbilical cord and maternal blood leptin concentrations in intrauterine growth retardation

Leptin, the ob gene product, plays an important role in the regulation of body fat mass and weight. In previous studies, it was demonstrated that leptin is detectable in human fetal cord blood as early as at 18 weeks of gestation and that serum leptin concentrations are significantly reduced in small gestational age newborns. In the present study, we investigated whether umbilical and maternal serum leptin concentrations correlate with intrauterine growth retardation (IUGR). In addition, we aimed to determine the relationships between leptin concentration in the maternal and cord blood. We studied 40 newborn infants (21 female and 19 male; gestational age, 38-42 weeks) and their mothers. Of the infants studied, 10 had IUGR. Serum leptin concentrations were measured by radioimmunoassay. All newborns had detectable leptin concentrations. Leptin concentrations were significantly lower in newborns with IUGR and in their mothers (n = 10; 3.53 +/- 1.42 ng/ml, 6.75 +/- 1.47 ng/ml, respectively) than in infants experiencing normal growth and their mothers (n = 30; 5.58 +/- 2.98 ng/ml, 9.85 +/- 6.50 ng/ml, respectively) (p < 0.01 for newborns, p < 0.05 for mothers). There was no significant correlation between umbilical leptin concentration and maternal leptin concentration (r = 0.229; p = 0.155) in all study groups but, significantly, a correlation was observed in the group with IUGR (r = 0.736; p = 0.015). There were no significant correlations between both umbilical and maternal leptin concentrations and parity, delivery type and gestational age. There was a correlation between umbilical leptin concentration and birth weight of newborns (r = 0.383; p = 0.015) but no correlation with body mass index (BMI) of the newborns (r = 0.034; p = 0.834). Maternal leptin concentrations correlated with maternal weight and BMI (r=0.606; p=0.000, r=0.535; p=0.000, respectively). There was no correlation between maternal leptin concentrations and birth weight of the newborns (r=0.179; p=0.269) and with BMI of the newborns (r = 0.146; p = 0.367). There was no gender difference in leptin concentrations in the newborns (n=21; 5.50 +/- 3.37 ng/ml, for females; n = 19; 4.58 +/- 1.98 ng/ml for males) (p = 0.296). In summary, we have shown that IUGR is associated with a decreased leptin concentration in newborns and their mothers. The association between umbilical serum leptin and birth weight in this and other studies suggests a pivotal role of fetal leptin in regulating fetal growth and development.

The effect of gender and gestational diabetes mellitus on cord leptin concentration

OBJECTIVE

The purpose of this study was to determine the relationship of neonatal sex and gestational diabetes mellitus on cord leptin concentration and to determine whether cord leptin has a stronger correlation with fat mass compared with birth weight or lean body mass. We hypothesized that there are no significant differences in fetal leptin concentration between male and female or between neonates of mothers with gestational diabetes mellitus and control neonates, when adjusted for body composition.

STUDY DESIGN

Cord blood leptin concentrations were measured in newborn infants of 78 women (44 control neonates and 34 gestational diabetes mellitus). Of the 78 neonates, 32 babies were female, and 46 babies were male. Birth weights were measured with a calibrated scale, and body compositions were measured by total body electrical conductivity.

RESULTS

Estimated mean gestational age at delivery was 39.1 +/- 1.1 weeks for control neonates versus 38.6 +/- 1.3 weeks for neonates of mothers with gestational diabetes mellitus (P =.01). The fat mass for the control neonates and neonates of mothers with gestational diabetes mellitus was 0.36 +/- 0.15 kg versus 0.48 +/- 0.21 kg (P =.01); the percent body fat for the control neonates and neonates of mothers with gestational diabetes mellitus was 10.5% +/- 3.8% versus 13.2% +/- 4.3% (P =.006), respectively. There was no significant difference in cord leptin concentration between male and female neonates (16.0 +/- 13.8 ng/dL vs 12.7 +/- 12.8 ng/dL, P =.24). Cord leptin concentrations (18.1 +/- 16.2 ng/dL vs 10.9 +/- 9.5 ng/dL, P =.02) were significantly greater in neonates of mothers with gestational diabetes mellitus than in control neonates. In all subjects, cord leptin was significantly correlated with percent body fat (r = 0.51, P <.0001), fat mass (r = 0.49,P <.0001), and birth weight (r = 0.25, P =.03). After the adjustment for fat mass, there was no significant difference in cord leptin concentration between control neonates and neonates of mothers with gestational diabetes mellitus (P =.20), but there was a significant difference between male and female neonates (P =.04). However, when an adjustment was made for both fat mass and lean body mass, there was no longer a significant difference between male and female neonates (P =.12)

CONCLUSION

The differences in cord leptin concentration between male and female neonates and between infants of women with gestational diabetes mellitus and control neonates are related to differences in body composition.

Malnutrition during lactation as a metabolic imprinting factor inducing the feeding pattern of offspring rats when adults. The role of insulin and leptin

The aim of the present study was to determine the impact of malnutrition during early postnatal life and the feeding pattern of rat offspring when adults (2 months and 1 year old). In comparison with rats normally fed during lactation, we observed that adult offspring displayed a faster process of feeding reduction when a protein-free diet was offered. In addition, we studied the concentration of insulin and leptin in the lactating pups (10 days) and when these offspring became adult after the onset of a new feeding pattern induced by the protein-free diet. When the diet was changed at 60 days, the offspring malnourished during lactation displayed, after 3 days, a food intake reduction around 41.4 vs 14.2% of the control group. At 10 days of life, plasma leptin and insulin were higher in the malnourished pups when compared with normally fed rats (leptin: 4.6 +/- 0.8 vs 2.25 ng/ml; insulin: 0.73 +/- 0.12 vs 0.22 +/- 0.03 ng/ml) while at 60 days they showed reduction of both hormones when compared with the control group (leptin: 1.03 +/- 0.25 vs 1.43 +/- 0.5 ng/ml; insulin: 0.54 +/- 0.3 vs 0.61 +/- 0.4 ng/ml). Despite the different food intake reductions, the malnourished and control rats displayed a similar reduction of insulin and leptin after 3 days of protein-free diet (from 60 to 63 days). The data suggest that the high concentration of insulin and leptin found at 10 days in the malnourished pups may elicit a sustained long-term and unique feeding pattern.

Umbilical cord plasma leptin is increased in preeclampsia

OBJECTIVE

The objective of this study was to compare umbilical cord plasma leptin between infants of mothers who experienced preeclampsia and infants of control subjects and to study the relation between cord plasma leptin and infant obesity, as indicated by ponderal index.

STUDY DESIGN

On the basis of a population of approximately 13,000 deliveries, we compared cord plasma leptin from preeclamptic (n = 256 women) and control pregnancies (n = 607 women) after taking the differences in gestational age and ponderal index into account.

RESULTS

Cord plasma leptin increased strongly with gestational age, both in the preeclampsia group and the control subjects (P <.01), but at each gestational age the preeclampsia group had higher leptin levels than control subjects (P <.01). Adjustment for the higher ponderal index among control subjects (P <.05) did not alter the difference in leptin levels between the groups.

CONCLUSION

We found higher levels of umbilical cord plasma leptin in infants of mothers who had preeclampsia (compared with infants of control subjects) after adjusting for differences in gestational age, gender, and infant ponderal index.