Nutritional programming of hypothalamic development: critical periods and windows of opportunity

Inflammation as a Sex-Specific Mediator in the Relationship between Maternal and Offspring Obesity in C57Bl/6J Mice

Maternal obesity is a well-established risk factor for offspring obesity development. The relationship between maternal and offspring obesity is mediated in part by developmental programming of offspring metabolic circuitry, including hypothalamic signaling. Dysregulated hypothalamic inflammation has also been linked to development of obesity. We utilized an established C57Bl/6J mouse model of high-fat, high-sugar diet induced maternal obesity to evaluate the effect of maternal obesity on systemic and hypothalamic TNF-α, IL-6, and IL-1β levels in neonatal and adult offspring. The offspring of dams with obesity demonstrated increased adiposity and decreased activity compared to control offspring. Maternal obesity was associated with decreased plasma TNF-α, IL-6 and IL-1β in adult female offspring and decreased plasma IL-6 in neonatal male offspring. Neonatal female offspring of obese dams had decreased TNF-α gene expression in the hypothalamus compared to control females, while neonatal and adult male offspring of obese dams had decreased IL-6 gene expression in the hypothalamus compared to control males. In summary, our results highlight important sex differences in the inflammatory phenotype of offspring exposed to maternal obesity. Sex-specific immunomodulatory mechanisms should be considered in future efforts to develop therapeutic interventions for obesity prevention and treatment.

Preterm birth: A neuroinflammatory origin for metabolic diseases?

Preterm birth and its related complications have become more and more common as neonatal medicine advances. The concept of "developmental origins of health and disease" has raised awareness of adverse perinatal events in the development of diseases later in life. To explore this concept, we propose that encephalopathy of prematurity (EoP) as a potential pro-inflammatory early life event becomes a novel risk factor for metabolic diseases in children/adolescents and adulthood. Here, we review epidemiological evidence that links preterm birth to metabolic diseases and discuss possible synergic roles of preterm birth and neuroinflammation from EoP in the development of metabolic diseases. In addition, we explore theoretical underlying mechanisms regarding developmental programming of the energy control system and HPA axis.

LAT1-dependent placental methionine uptake is a key player in fetal programming of metabolic disease

The Developmental Origins of Health and Disease hypothesis sustains that exposure to different stressors during prenatal development prepares the offspring for the challenges to be encountered after birth. We studied the gestational period as a particularly vulnerable window where different stressors can have strong implications for fetal programming of the offspring's life-long metabolic status via alterations of specific placentally expressed nutrient transporters. To study this mechanism, we used a murine prenatal stress model, human preeclampsia, early miscarriage, and healthy placental tissue samples, in addition to in vitro models of placental cells. In stressed mice, placental overexpression of L-type amino acid transporter 1 (Lat1) and subsequent global placental DNA hypermethylation was accompanied by fetal and adult hypothalamic dysregulation in global DNA methylation and gene expression as well as long-term metabolic abnormalities exclusively in female offspring. In human preeclampsia, early miscarriage, and under hypoxic conditions, placental LAT1 was significantly upregulated, leading to increased methionine uptake and global DNA hypermethylation. Remarkably, subgroups of healthy term placentas with high expression of stress-related genes presented increased levels of placental LAT1 mRNA and protein, DNA and RNA hypermethylation, increased methionine uptake capacity, one-carbon metabolic pathway disruption, higher methionine concentration in the placenta and transport to the fetus specifically in females. Since LAT1 mediates the intracellular accumulation of methionine, global DNA methylation, and one-carbon metabolism in the placenta, our findings hint at a major sex-specific global response to a variety of prenatal stressors affecting placental function, epigenetic programming, and life-long metabolic disease and provide a much-needed insight into early-life factors predisposing females/women to metabolic disorders.

Leptin and adiposity measures from birth to later childhood: Findings from the Hyperglycemia and Adverse Pregnancy Outcomes Follow-Up Study

BACKGROUND

Cord blood (CB) leptin is positively associated with adiposity at birth, but the association with child adiposity is unclear.

OBJECTIVES

We hypothesized that CB leptin is positively associated with adiposity in peripubertal children and with childhood leptin.

METHODS

Leptin was measured in 986 CB and 931 childhood stored samples from a prospective birth cohort. Adiposity measures were collected at birth and mean age 11.5 years. Linear and logistic regression analyses were used to evaluate associations between log-transformed CB leptin and neonatal and childhood adiposity measures as continuous and categorical variables, respectively.

RESULTS

CB leptin was positively associated with neonatal and childhood adiposity. Childhood associations were attenuated when adjusted for maternal body mass index (BMI) and glucose, but remained statistically significant for childhood body fat percentage (β = 1.15%, confidence interval [CI] = 0.46-1.84), body fat mass (β = 0.69 kg, 95% CI = 0.16-1.23), sum of skin-folds (β = 1.77 mm, 95% CI = 0.31-3.24), log-transformed child serum leptin (β = 0.13, 95% CI = 0.06-0.20), overweight/obesity (OR = 1.21, 95% CI = 1.03-1.42), obesity (OR = 1.31, 95% CI = 1.04-1.66) and body fat percentage >85th percentile (OR = 1.38, 95% CI = 1.12-1.73). Positive associations between newborn adiposity measures and CB leptin confirmed previous reports.

CONCLUSION

CB leptin is positively associated with neonatal and childhood adiposity and child leptin levels, independent of maternal BMI and maternal hyperglycemia. CB leptin may be a biomarker of future adiposity risk.

Methyl donor micronutrients, hypothalamic development and programming for metabolic disease

Nutriture in utero is essential for fetal brain development through the regulation of neural stem cell proliferation, differentiation, and apoptosis, and has a long-lasting impact on risk of disease in offspring. This review examines the role of maternal methyl donor micronutrients in neuronal development and programming of physiological functions of the hypothalamus, with a focus on later-life metabolic outcomes. Although evidence is mainly derived from preclinical studies, recent research shows that methyl donor micronutrients (e.g., folic acid and choline) are critical for neuronal development of energy homeostatic pathways and the programming of characteristics of the metabolic syndrome in mothers and their children. Both folic acid and choline are active in one-carbon metabolism with their impact on epigenetic modification of gene expression. We conclude that an imbalance of folic acid and choline intake during gestation disrupts DNA methylation patterns affecting mechanisms of hypothalamic development, and thus elevates metabolic disease risk. Further investigation, including studies to determine translatability to humans, is required.

Weight Gain in Early Infancy Impacts Appetite Regulation in the First Year of Life. A Prospective Study of Infants Living in Cyprus

BACKGROUND

Eating behavior is associated with weight gain in infancy and childhood. Few studies found a bidirectional association between weight gain and eating behavior development in childhood, but there is little data on the association in early infancy, a period critical for the programming of obesity risk.

OBJECTIVE

We investigated the bidirectional association between appetite traits and weight gain during the first year of life.

METHODS

Participants were part of a cohort of 432 infants born in Cyprus. Appetite traits were measured using the Baby Eating Behavior Questionnaire or the Child Eating Behavior Questionnaire at age 2 to 4 wk, 6 mo, and 12 mo. Weight and length were collected at birth, 4 wk, 6 mo, and 12 mo. Multivariable linear regression was used to analyze associations between appetite traits at 2 to 4 wk and 6 mo and weight for age z-score change (WFAZC) between 4 wk and 6 mo and 6 and 12 mo. Associations were also analyzed in the opposite direction, between WFAZC from birth to 4 wk, 4 wk to 6 mo, and 6 mo to 12 mo and appetite traits at 4 wk, 6 mo, and 12 mo.

RESULTS

Satiety responsiveness (SR) at 2 to 4 wk was associated with lower WFAZC from 4 wk to 6 mo (β: -0.17; 95% CI: -0.30, -0.04) and SR at age 6 mo was associated with lower WFAZC from 6 to 12 mo (β: -0.09; 95% CI: -0.17, -0.02). WFAZC from 4 wk to 6 mo was associated with higher enjoyment of food at 12 mo (β: 0.11; 95% CI: 0.01, 0.20), higher food responsiveness at 12 mo (β: 0.17; 95% CI: 0.04, 0.30), and lower SR at both 6 mo (β: -0.11; 95% CI: -0.21, -0.01) and 12 mo (β: -0.14; 95% CI: -0.24, -0.03).

CONCLUSIONS

We found a bidirectional association between weight gain and appetite traits in infancy, suggesting that the effect of postnatal weight gain on obesity development is partly mediated by programming of appetite traits.

Gestational exposure to continuous light impairs the development of the female reproductive system in adult Wistar rat offspring

INTRODUCTION

It has been suggested that maternal exposure to constant light during the gestational period could be considered as a chronic stressor, impairing offspring development by interfering in neuroendocrine and behavior responses.

OBJECTIVE

This study aimed to evaluate whether maternal exposure to continuous light during pregnancy affects the adult reproductive system in the female offspring.

MATERIALS AND METHODS

Pregnant Wistar rats were allocated into light-dark (LD) group, exposed to light and dark photoperiod during gestation, and the light-light (LL) group, exposed to a photoperiod of constant light during gestation. After birth, pups were maintained under normal light-dark photoperiod until adulthood. At postnatal day 90, blood was collected from the female offspring, to analyze plasma luteinizing hormone (LH) and progesterone levels, and the uterus and ovaries were harvested for morphometric, histological, and oxidative stress evaluations.

RESULTS AND DISCUSSION

Female exposure to continuous light during the intrauterine period resulted in the adult reduction of LH and increased progesterone plasma levels, and uterine injuries a higher number of endometrial glands and reduced levels of antioxidant enzymes, such as glutathione reductase and glutathione S-transferase. In these experimental conditions, gestational continuous light exposure disturbs sex hormone balance and reduces the antioxidant enzymatic activity in the uterus of female offspring in adult life.

Emerging role of hypothalamus in the metabolic regulation in the offspring of maternal obesity

Maternal obesity has a significant impact on the metabolism of offspring both in childhood and adulthood. The metabolic regulation of offspring is influenced by the intrauterine metabolic programming induced by maternal obesity. Nevertheless, the precise mechanisms remain unclear. The hypothalamus is the primary target of metabolic programming and the principal regulatory center of energy metabolism. Accumulating evidence has indicated the crucial role of hypothalamic regulation in the metabolism of offspring exposed to maternal obesity. This article reviews the development of hypothalamus, the role of the hypothalamic regulations in energy homeostasis, possible mechanisms underlying the developmental programming of energy metabolism in offspring, and the potential therapeutic approaches for preventing metabolic diseases later in life. Lastly, we discuss the challenges and future directions of hypothalamic regulation in the metabolism of children born to obese mothers.

Maternal Protein Restriction in Rats Alters Postnatal Growth and Brain Lipid Sensing in Female Offspring

Perinatal nutrition is a key player in the susceptibility to developing metabolic diseases in adulthood, leading to the concept of "metabolic programming". The aim of this study was to assess the impact of maternal protein restriction during gestation and lactation on glucose homeostasis and eating behaviour in female offspring. Pregnant rats were fed a normal or protein-restricted (PR) diet and followed throughout gestation and lactation. Body weight, glucose homeostasis, and eating behaviour were evaluated in offspring, especially in females. Body weight gain was lower in PR dams during lactation only, despite different food and water intakes throughout gestation and lactation. Plasma concentration of leptin, adiponectin and triglycerides increased drastically before delivery in PR dams in relation to fat deposits. Although all pups had identical birth body weight, PR offspring body weight differed from control offspring around postnatal day 10 and remained lower until adulthood. Offspring glucose homeostasis was mildly impacted by maternal PR, although insulin secretion was reduced for PR rats at adulthood. Food intake, satiety response, and cerebral activation were examined after a lipid preload and demonstrated some differences between the two groups of rats. Maternal PR during gestation and lactation does induce extrauterine growth restriction, accompanied by alterations in maternal plasma leptin and adiponectin levels, which may be involved in programming the alterations in eating behaviour observed in females at adulthood.

In utero choline exposure alters growth, metabolism, feed efficiency, and carcass characteristics of Holstein × Angus cattle from weaning to slaughter

Feeding rumen-protected choline (RPC) to late gestation dairy cows has potential to affect growth in offspring. The objective of this study was to evaluate the effects of in utero choline exposure on the growth, feed efficiency (FE), metabolism, and carcass quality of Angus × Holstein cattle. Multiparous Holstein cows pregnant with male (N = 17) or female (N = 30) Angus-sired calves were enrolled 21 d prepartum and randomly assigned to one of four dietary treatments varying in quantity and formulation of RPC. The treatments included a control with 0 g/d supplemental RPC (CTL), supplemental RPC fed at the recommended dose (RD) of 15 g/d from either an established RPC product (RPC1RD; ReaShure; Balchem Corp.) or choline ion from a concentrated RPC prototype (RPC2RD; Balchem Corp.), or a high dose (HD) of RPC2 fed at 22 g/d (RPC2HD). From 2 to 6 mo of age, calves were group housed and offered 2.3 kg grain/hd/d (42% CP) with ad libitum grass hay, and stepped up to a complete finishing diet by 7 mo (12.0% CP; 1.34 Mcal/kg NEg). Weight and height were measured monthly. Animal FE was measured in individual pens for 35 d at 8 mo. Feed intake was measured daily, and blood was obtained on day 18 during the FE period. Afterwards, cattle were group housed and offered a free-choice finishing diet until slaughter, where carcass yield and quality characteristics were measured. Mixed models were used in PROC MIXED (SAS, 9.4) with the fixed effects of treatment, sex, time, their interactions, and the random effect of calf. Month was the repeated measure, and preplanned contrasts were used. Blood and FE data were analyzed with the fixed effect of dam choline treatment, calf sex, and the interaction. Increasing dose of RPC tended to increase weight over the entire study period. Feeding any RPC increased hip and wither height compared with CTL, and increasing RPC dose linearly increased hip and wither height. Treatment and sex interacted on DMI whereby increasing RPC intake linearly increased DMI for males but not females. Compared with control, feeding any RPC decreased plasma insulin, glucose, and an insulin sensitivity index (RQUICKI). In utero choline exposure increased kidney-pelvic-heart fat and marbling score. Mechanisms of action for intrauterine choline exposure on offspring growth, metabolism, and carcass characteristics should be explored as they have direct implications for profitability for cattle growers and feeders.

Maternal prenatal cortisol and the interaction of income and pre-pregnancy body mass index are independently associated with newborn cortisol

While extensive research has supported the developmental programming hypothesis regarding contributions of prenatal psychosocial or nutritional adversity to offspring stress physiology, fewer studies consider both exposures together with maternal stress physiology. This study examined newborn cortisol output during a stressor as a function of maternal pre-pregnancy health status and nutritional history (pre-pregnancy body mass index [PPBMI]), economic resources (household income), and maternal cortisol awakening response (mCAR) in late pregnancy. Participants were 102 mother-infant pairs from an economically and racial/ethnically diverse sample. Offspring salivary cortisol response to a neurobehavioral exam was assessed at 1 month. Income and maternal PPBMI were positively associated with mCAR in late pregnancy. mCAR was positively related to 1-month newborn cortisol response. The interaction of income and PPBMI was positively associated with newborn cortisol output during an exam at 1-month. Mothers with the highest PPBMI and lowest income had offspring with higher cortisol responses than offspring of mothers with higher income and lower PPBMI. There was no evidence of indirect mediation effects of predictors (PPBMI, income, and interaction) on infant cortisol via mCAR. The differential effects of the interaction of PPBMI and income suggest that these exposures influence infant cortisol output in the context of one another, independent of maternal pregnancy cortisol.

Associations between Cord Blood Leptin Levels and Childhood Adiposity Differ by Sex and Age at Adiposity Assessment

Lower cord blood leptin levels have been associated with lower and higher adiposity in childhood and associations seem to differ according to the child’s age, methods of adiposity assessment and sex. Our aim was to investigate sex-specific associations of cord blood leptinemia with childhood adiposity at birth, 3 and 5 years of age. We measured cord blood leptin using Luminex immunoassays in 520 offspring from the Gen3G cohort. We tested associations between cord blood leptin and body mass index (BMI) z-score, skinfolds thicknesses (SFT), and body composition using dual-energy X-ray absorptiometry, adjusted for confounders. At birth, girls had almost twice as much leptin in cord blood as boys (15.5 [8.9; 25.6] vs. 8.6 [4.9; 15.0] ng/mL; p < 0.0001) as well as significantly greater adiposity. Lower levels of cord blood leptin were associated with higher sum of SFT (β = −0.05 ± 0.02; p = 0.03) and higher BMI z-score (β= −0.22 ± 0.08; p = 0.01) in 3-year-old boys only. We did not observe these associations at age 5, or in girls. Our results suggest a sexual dimorphism in the programming of leptin sensitivity and childhood adiposity, but further observational and functional studies are needed to better understand the role of leptin in early life.

Maternal and fetal factors affecting cord plasma leptin and adiponectin levels and their ratio in preterm and term newborns: New insight on fetal origins of metabolic dysfunction

Background

Understanding of maternal and fetal factors affecting leptin, adiponectin and adiponectin: leptin ratio at birth, may provide valuable insights into potential future risk of metabolic alterations and inform primordial prevention and precision nutrition strategies.

Objective

To identify maternal and fetal risk factors that affect leptin and adiponectin levels (markers of adiposity) and adiponectin/leptin ratio (a marker of dysfunctional adipose tissue) at birth.

Methods

We studied mother-infant pairs in the Boston Birth Cohort. Cord blood was collected at birth. We used student t-tests to compare log normalized cord leptin and adiponectin levels. Regression analysis were performed to examine the association of maternal and fetal factors with leptin and adiponectin levels and adiponectin: leptin ratio at birth in both term and preterm infants.

Results

We analyzed 1012 infants (245 preterm). Both cord leptin and adiponectin were higher in term infants than preterm infants (10.2 ± 0.9 vs. 9.2 ± 1.3, p < 0.0001 and 9.5 ± 0.7 vs. 8.9 ± 0.8, p < 0.0001 respectively). Cord leptin was higher for Black infants (10.1 ± 1.1 vs. 9.9 ± 1.2; p < 0.001) although Black (ref: non Black) infants had lower cord adiponectin levels (9.3 ± 0.8 vs. 9.5 ± 0.7; p = 0.01). Ratio of adiponectin to leptin (log normalized) was higher in preterm infants (-0.24) vs. term infants (-0.69). On regression analysis cord leptin was positively associated with longer gestational age, birth weight z score, Black race, maternal overweight and obesity, gestational diabetes and pregestational diabetes mellitus and negatively associated with male sex. Cord adiponectin was positively associated with gestational age, birth weight z score and negatively with Black race and male sex. Adiponectin: leptin ratio was positively with male sex and negatively with GA, birth wt. z score, Black race, gestational DM, pregestational DM and maternal overweight and obesity.

Conclusion

We identified several factors that affect leptin and adiponectin levels along with adiponectin-leptin ratio at birth beyond GA and birth weight which could also play an important role in influencing the trajectory of these hormones and future cardio metabolic outcomes. This knowledge can help tailor precision nutrition interventions.

Female and male C57BL/6J offspring exposed to maternal obesogenic diet develop altered hypothalamic energy metabolism in adulthood

Maternal obesity is exceedingly common and strongly linked to offspring obesity and metabolic disease. Hypothalamic function is critical to obesity development. Hypothalamic mechanisms causing obesity following exposure to maternal obesity have not been elucidated. Therefore, we studied a cohort of C57BL/6J dams, treated with a control or high-fat-high-sugar diet, and their adult offspring to explore potential hypothalamic mechanisms to explain the link between maternal and offspring obesity. Dams treated with obesogenic diet were heavier with mild insulin resistance, which is reflective of the most common metabolic disease in pregnancy. Adult offspring exposed to maternal obesogenic diet had no change in body weight but significant increase in fat mass, decreased glucose tolerance, decreased insulin sensitivity, elevated plasma leptin, and elevated plasma thyroid-stimulating hormone. In addition, offspring exposed to maternal obesity had decreased energy intake and activity without change in basal metabolic rate. Hypothalamic neurochemical profile and transcriptome demonstrated decreased neuronal activity and inhibition of oxidative phosphorylation. Collectively, these results indicate that maternal obesity without diabetes is associated with adiposity and decreased hypothalamic energy production in offspring. We hypothesize that altered hypothalamic function significantly contributes to obesity development. Future studies focused on neuroprotective strategies aimed to improve hypothalamic function may decrease obesity development.NEW & NOTEWORTHY Offspring exposed to maternal diet-induced obesity demonstrate a phenotype consistent with energy excess. Contrary to previous studies, the observed energy phenotype was not associated with hyperphagia or decreased basal metabolic rate but rather decreased hypothalamic neuronal activity and energy production. This was supported by neurochemical changes in the hypothalamus as well as inhibition of hypothalamic oxidative phosphorylation pathway. These results highlight the potential for neuroprotective interventions in the prevention of obesity with fetal origins.

Edible insects prevent changes to brain monoamine profiles from malnourishment in weaned rats

Background: Childhood malnutrition can have devastating consequences on health, behavior, and cognition. Edible insects are sustainable low cost high protein and iron nutritious foods that can prevent malnutrition. However, it is unclear whether insect-based diets may help prevent changes to brain neurochemistry associated with malnutrition.Materials and Methods: Weanling male Sprague-Dawley rats were malnourished by feeding a low protein-iron diet (LPI, 5% protein and ∼2 ppm Fe) for 3 weeks or nourished by feeding a sufficient protein-iron diet (SPI, 15% protein 20 ppm FeSO₄) for the duration of the study. Following 3 weeks of LPI diet, three subsets of the malnourished rats were placed on repletion diets supplemented with cricket, palm weevil larvae, or the SPI diet for 2 weeks, while the remaining rats continued the LPI diet for an additional 2 weeks. Monoamine-related neurochemicals (e.g. serotonin (5-HT), dopamine (DA), norepinephrine) and select monoamine metabolites were measured in the hypothalamus, hippocampus, striatum, and prefrontal cortex using Ultra High-Performance Liquid Chromatography.Results: Five weeks of LPI diets disrupted brain monoamines, most notable in the hypothalamus. Two weeks supplementation with cricket and palm weevil larvae diets prevented changes to measures of 5-HT and DA turnover in the hippocampus and hypothalamus. Moreover, these insect diets prevented the malnutrition-induced imbalance of 5-HT and DA metabolites in the hippocampus, striatum, and hypothalamus.Conclusion: Edible insects such as cricket and palm weevil larvae could be sustainable nutrition intervention to prevent behavioral and cognitive impairment associated abnormal brain monoamine activities that results from early life malnutrition.

Maternal and fetal factors affecting cord plasma leptin and adiponectin levels and their ratio in preterm and term newborns: New insight on fetal origins of metabolic dysfunction

Background

Understanding of maternal and fetal factors affecting leptin, adiponectin, and adiponectin:leptin ratio at birth may provide valuable insights into potential future risk of metabolic alterations and inform primordial prevention and precision nutrition strategies. The objective of this study is to identify maternal and fetal risk factors that affect leptin and adiponectin levels (markers of adiposity) and adiponectin/leptin ratio (a marker of dysfunctional adipose tissue) at birth.

Methods

We studied mother-infant pairs in the Boston Birth Cohort. Cord blood was collected at birth. We used student t- tests to compare log normalized cord leptin and adiponectin levels. Regression analysis was performed to examine the association of maternal and fetal factors with leptin and adiponectin levels and adiponectin:leptin ratio at birth in both term and preterm infants.

Results

We analyzed 1012 infants (245 preterm). Both cord leptin and adiponectin were higher in term infants than preterm infants (10.2 ± 0.9 vs. 9.2 ± 1.3, P < 0.0001 and 9.5 ± 0.7 vs. 8.9 ± 0.8, P < 0.0001, respectively). Cord leptin was higher for Black infants (10.1 ± 1.1 vs. 9.9 ± 1.2; P < 0.001) although Black (ref: non-Black) infants had lower cord adiponectin levels (9.3 ± 0.8 vs. 9.5 ± 0.7; P = 0.01). Ratio of adiponectin to leptin (log normalized) was higher in preterm infants (-0.24) vs. term infants (-0.69). On regression analysis, cord leptin was positively associated with longer gestational age (GA), birth weight z score, Black race, maternal overweight and obesity, gestational diabetes and pregestational diabetes mellitus and negatively associated with male sex. Cord adiponectin was positively associated with GA, birth weight z score and negatively with Black race and male sex. Adiponectin:leptin ratio was positively with male sex and negatively with GA, birth weight z score, Black race, gestational DM, pregestational DM and maternal overweight and obesity.

Conclusions

We identified several factors that affect leptin and adiponectin levels along with adiponectin-leptin ratio at birth beyond GA and birth weight which could also play an important role in influencing the trajectory of these hormones and future cardiometabolic outcomes. This knowledge can help tailor precision nutrition interventions.

Determinants of cord blood adipokines and association with neonatal abdominal adipose tissue distribution

BACKGROUND

Cord blood leptin and adiponectin are adipokines known to be associated with birth weight and overall infant adiposity. However, few studies have investigated their associations with abdominal adiposity in neonates. We examined maternal factors associated with cord blood leptin and adiponectin, and the association of these adipokines with neonatal adiposity and abdominal fat distribution measured by magnetic resonance imaging (MRI) in an Asian mother-offspring cohort.

METHODS

Growing Up in Singapore Towards healthy Outcomes (GUSTO), is a prospective mother-offspring birth cohort study in Singapore. Cord blood plasma leptin and adiponectin concentrations were measured using Luminex and Enzyme-Linked Immunosorbent Assay respectively in 816 infants. A total of 271 neonates underwent MRI within the first 2-weeks after delivery. Abdominal superficial (sSAT), deep subcutaneous (dSAT), and intra-abdominal (IAT) adipose tissue compartment volumes were quantified from MRI images. Multivariable regression analyses were performed.

RESULTS

Indian or Malay ethnicity, female sex, and gestational age were positively associated with cord blood leptin and adiponectin concentrations. Maternal gestational diabetes (GDM) positively associated with cord blood leptin concentrations but inversely associated with cord blood adiponectin concentrations. Maternal pre-pregnancy body mass index (BMI) showed a positive relationship with cord blood leptin but not with adiponectin concentrations. Each SD increase in cord blood leptin was associated with higher neonatal sSAT, dSAT and IAT; differences in SD (95% CI): 0.258 (0.142, 0.374), 0.386 (0.254, 0.517) and 0.250 (0.118, 0.383), respectively. Similarly, each SD increase in cord blood adiponectin was associated with higher neonatal sSAT and dSAT; differences in SD (95% CI): 0.185 (0.096, 0.274) and 0.173 (0.067, 0.278), respectively. The association between cord blood adiponectin and neonatal adiposity was observed in neonates of obese mothers only.

CONCLUSIONS

Cord blood leptin and adiponectin concentrations were associated with ethnicity, maternal BMI and GDM, sex and gestational age. Both adipokines showed positive association with neonatal abdominal adiposity.

Prenatal Pollutant Exposures and Hypothalamic Development: Early Life Disruption of Metabolic Programming

Environmental contaminants in ambient air pollution pose a serious risk to long-term metabolic health. Strong evidence shows that prenatal exposure to pollutants can significantly increase the risk of Type II Diabetes (T2DM) in children and all ethnicities, even without the prevalence of obesity. The central nervous system (CNS) is critical in regulating whole-body metabolism. Within the CNS, the hypothalamus lies at the intersection of the neuroendocrine and autonomic systems and is primarily responsible for the regulation of energy homeostasis and satiety signals. The hypothalamus is particularly sensitive to insults during early neurodevelopmental periods and may be susceptible to alterations in the formation of neural metabolic circuitry. Although the precise molecular mechanism is not yet defined, alterations in hypothalamic developmental circuits may represent a leading cause of impaired metabolic programming. In this review, we present the current knowledge on the links between prenatal pollutant exposure and the hypothalamic programming of metabolism.

Extended light period in the maternal circadian cycle impairs the reproductive system of the rat male offspring

Alterations in the circadian cycle are known to cause physiological disorders in the hypothalamic-pituitary-adrenal and the hypothalamic-pituitary-gonadal axes in adult individuals. Therefore, the present study aimed to evaluate whether exposure of pregnant rats to constant light can alter the reproductive system development of male offspring. The dams were divided into two groups: a light-dark group (LD), in which pregnant rats were exposed to an LD photoperiod (12 h/12 h) and a light-light (LL) group, in which pregnant rats were exposed to a photoperiod of constant light during the gestation period. After birth, offspring from both groups remained in the normal LD photoperiod (12 h/12 h) until adulthood. One male of each litter was selected and, at adulthood (postnatal day (PND) 90), the trunk blood was collected to measure plasma testosterone levels, testes and epididymis for sperm count, oxidative stress and histopathological analyses, and the spermatozoa from the vas deferens to perform the morphological and motility analyses. Results showed that a photoperiod of constant light caused a decrease in testosterone levels, epididymal weight and sperm count in the epididymis, seminiferous tubule diameter, Sertoli cell number, and normal spermatozoa number. Histopathological damage was also observed in the testes, and stereological alterations, in the LL group. In conclusion, exposure to constant light during the gestational period impairs the reproductive system of male offspring in adulthood.

Excess sucrose intake during pregnancy programs fetal brain glucocorticoid receptor expression in female but not male C57Bl/6J mice

BACKGROUND

Sex-specific mechanisms explaining the association between mothers with obesity and the development of obesity in children are poorly characterized. Permanent changes in fetal brain glucocorticoid receptor (GR) expression caused by exposure to overnutrition in utero may program aberrant energy homeostasis, thereby predisposing the offspring to obesity. This study explores sex differences in brain GR expression using an established mouse model of overnutrition during pregnancy.

METHODS

Female C57Bl/6J mice were fed control (CON) or high-fat-high-sucrose (HFHS) diets. Dam cholesterol, insulin, and triglycerides were measured by colorimetric assays. Fetal corticosterone exposure was measured by placental Abca1, Hsd11β1, Hsd11β2, and brain Nr3c1 (GR); Pomc expression measured by RT-qPCR.

RESULTS

Female, but not male, HFHS fetuses had 46% decreased brain GR and twofold increased Pomc expression. There was decreased Abca1 and Hsd11β1 but not Hsd11β2 expression in HFHS placentas. Caloric and sucrose intake, but not fat intake, in dams inversely correlated with fetal GR expression in both sexes. Excess sucrose consumption by dams inversely correlated with female fetal GR and directly correlated with female fetal Pomc expression.

CONCLUSIONS

Excess sucrose consumption in pregnant dams caused lower GR and higher Pomc expression in the female fetal brain. Clinical investigation of excess sucrose intake during pregnancy and its subsequent effect on hypothalamic-pituitary-adrenal axis activity and appetite in offspring may lead to novel, sex-specific obesity prevention strategies in the development of obesity in children.

Modulation of the Hypothalamic Nutrient Sensing Pathways by Sex and Early-Life Stress

There are sex differences in metabolic disease risk, and early-life stress (ES) increases the risk to develop such diseases, potentially in a sex-specific manner. It remains to be understood, however, how sex and ES affect such metabolic vulnerability. The hypothalamus regulates food intake and energy expenditure by sensing the organism's energy state via metabolic hormones (leptin, insulin, ghrelin) and nutrients (glucose, fatty acids). Here, we investigated if and how sex and ES alter hypothalamic nutrient sensing short and long-term. ES was induced in mice by limiting the bedding and nesting material from postnatal day (P)2-P9, and the expression of genes critical for hypothalamic nutrient sensing were studied in male and female offspring, both at P9 and in adulthood (P180). At P9, we observed a sex difference in both Ppargc1a and Lepr expression, while the latter was also increased in ES-exposed animals relative to controls. In adulthood, we found sex differences in Acacb, Agrp, and Npy expression, whereas ES did not affect the expression of genes involved in hypothalamic nutrient sensing. Thus, we observe a pervasive sex difference in nutrient sensing pathways and a targeted modulation of this pathway by ES early in life. Future research is needed to address if the modulation of these pathways by sex and ES is involved in the differential vulnerability to metabolic diseases.

Exosome-Derived MicroRNAs of Human Milk and Their Effects on Infant Health and Development

Multiple biologically active components of human milk support infant growth, health and development. Milk provides a wide spectrum of mammary epithelial cell-derived extracellular vesicles (MEVs) for the infant. Although the whole spectrum of MEVs appears to be of functional importance for the growing infant, the majority of recent studies report on the MEV subfraction of milk exosomes (MEX) and their miRNA cargo, which are in the focus of this review. MEX and the dominant miRNA-148a play a key role in intestinal maturation, barrier function and suppression of nuclear factor-κB (NF-κB) signaling and may thus be helpful for the prevention and treatment of necrotizing enterocolitis. MEX and their miRNAs reach the systemic circulation and may impact epigenetic programming of various organs including the liver, thymus, brain, pancreatic islets, beige, brown and white adipose tissue as well as bones. Translational evidence indicates that MEX and their miRNAs control the expression of global cellular regulators such as DNA methyltransferase 1-which is important for the up-regulation of developmental genes including insulin, insulin-like growth factor-1, α-synuclein and forkhead box P3-and receptor-interacting protein 140, which is important for the regulation of multiple nuclear receptors. MEX-derived miRNA-148a and miRNA-30b may stimulate the expression of uncoupling protein 1, the key inducer of thermogenesis converting white into beige/brown adipose tissue. MEX have to be considered as signalosomes derived from the maternal lactation genome emitted to promote growth, maturation, immunological and metabolic programming of the offspring. Deeper insights into milk's molecular biology allow the conclusion that infants are both "breast-fed" and "breast-programmed". In this regard, MEX miRNA-deficient artificial formula is not an adequate substitute for breastfeeding, the birthright of all mammals.

Maternal-infant nutrition and development programming of offspring appetite and obesity

In the United States and Mexico, the obesity epidemic represents a significant public health problem. Although obesity is often attributed to a Western-style, high-fat diet and decreased activity, there is now compelling evidence that this, in part, occurs because of the developmental programming effects resulting from exposure to maternal overnutrition. Human and animal studies demonstrate that maternal obesity and high-fat diet result in an increased risk for childhood and adult obesity. The potential programming effects of obesity have been partly attributed to hyperphagia, which occurs as a result of increased appetite with reduced satiety neuropeptides or neurons. However, depending on maternal nutritional status during the nursing period, the programmed hyperphagia and obesity can be exacerbated or prevented in offspring born to obese mothers. The underlying mechanism of this phenomenon likely involves the plasticity of the appetite regulatory center and thus presents an opportunity to modulate feeding and satiety regulation and break the obesity cycle.

Infant body composition relationship to maternal adipokines and fat mass: the PONCH study

BACKGROUND

Infant adiposity is linked to both high maternal fat mass (FM) and excessive gestational FM gain, whereas the association with maternal adipokines is less clear. The aim was to determine how levels of maternal leptin, the soluble leptin receptor (sOB-R), adiponectin, and FM during pregnancy were linked to infant FM in normal-weight (NW) women and women with obesity (OB).

METHODS

Body composition and serum levels of leptin, adiponectin, and sOB-R were determined three times during pregnancy in 80 NW and 46 OB women. For infants, body composition was measured at 1 and 12 weeks of age.

RESULTS

Maternal leptin and sOB-R levels increased during pregnancy. For NW women, infant FM at 1 week was inversely associated with changes in maternal leptin and at 12 weeks inversely associated with absolute maternal sOB-R levels throughout pregnancy, as well as changes in sOB-R levels in early pregnancy. For OB women, infant FM at both 1 and 12 weeks were best explained by maternal FM.

CONCLUSIONS

Leptin and sOB-R, thought to regulate leptin bioavailability, are associated with fat accumulation in infants born to NW women. In OB women, maternal FM in early pregnancy is more important than leptin in determining infant fat accumulation.

IMPACT

In normal-weight women, the regulation of maternal leptin bioavailability during pregnancy has a role in infant fat mass accumulation. In women with obesity, however, pre-pregnancy maternal fat mass seems more important for infant fat mass. This is the first study of maternal adipokines and fat mass including longitudinal measurements in both mothers and their children. Understanding the relationship between maternal factors and infant fat mass is of great importance as obesity is programmed over the generations, and it is important to learn what regulates this programming.

The relationship between maternal dietary patterns during pregnancy in women with gestational diabetes mellitus and infant appetitive feeding behaviour at 6 months

Early dietary exposure may influence infant appetitive feeding behaviour, and therefore their later health. Maternal diabetes in pregnancy is associated with an increased risk of obesity in the offspring. We, therefore, examined third-trimester dietary patterns of women with gestational diabetes, their offspring's appetitive feeding behaviour at 6 months of age, and relationships between these. We used data from a prospective cohort of women with gestational diabetes and assessed maternal dietary patterns at 36 weeks' gestation using principal component analysis; infant appetitive feeding behaviour at 6 months of age using the Baby Eating Behaviour Questionnaire; and relationships between these using general linear modelling and chi-square tests. In 325 mother-infant dyads, we identified three distinct maternal dietary patterns: 'Junk,' 'Mixed,' and 'Health-conscious.' The maternal 'Health-conscious' pattern was inversely associated with 'enjoyment of food' in their sons (β - 0.24, 95% CI - 0.36 to - 0.11, p = 0.0003), but not daughters (β - 0.02, 95% CI - 0.12 to 0.08, p = 0.70), and was positively associated with 'slowness in eating,' (β 0.13, 95% CI 0.02 to 0.24, p = 0.01). Third-trimester dietary patterns in women with gestational diabetes may have sex-specific effects on infant appetitive feeding behaviour at 6 months of age.

Primary cilia mediate early life programming of adiposity through lysosomal regulation in the developing mouse hypothalamus

Hypothalamic neurons including proopiomelanocortin (POMC)-producing neurons regulate body weights. The non-motile primary cilium is a critical sensory organelle on the cell surface. An association between ciliary defects and obesity has been suggested, but the underlying mechanisms are not fully understood. Here we show that inhibition of ciliogenesis in POMC-expressing developing hypothalamic neurons, by depleting ciliogenic genes IFT88 and KIF3A, leads to adulthood obesity in mice. In contrast, adult-onset ciliary dysgenesis in POMC neurons causes no significant change in adiposity. In developing POMC neurons, abnormal cilia formation disrupts axonal projections through impaired lysosomal protein degradation. Notably, maternal nutrition and postnatal leptin surge have a profound impact on ciliogenesis in the hypothalamus of neonatal mice; through these effects they critically modulate the organization of hypothalamic feeding circuits. Our findings reveal a mechanism of early life programming of adult adiposity, which is mediated by primary cilia in developing hypothalamic neurons.

Ciliary defects and obesity has been associated, but the underlying mechanism is unclear. Here, the authors show that inhibition of ciliogenesis in POMC neurons during development results in lysosomal protein degradation-dependent axonal disruption and adult obesity in mice.

Maternal High-Fat-High-Carbohydrate Diet-Induced Obesity Is Associated with Increased Appetite in Peripubertal Male but Not Female C57Bl/6J Mice

Diet-induced maternal obesity might play a critical role in altering hypothalamic development, predisposing the offspring to obesity and metabolic disease later in life. The objective of this study was to describe both phenotypic and molecular sex differences in peripubertal offspring energy homeostasis, using a mouse model of maternal obesity induced by a high-fat–high-carbohydrate (HFHC) diet. We report that males, not females, exposed to a maternal HFHC diet had increased energy intake. Males exposed to a maternal HFHC diet had a 15% increased meal size and a 46% increased frequency, compared to the control (CON) males, without a change in energy expenditure. CON and HFHC offspring did not differ in body weight, composition, or plasma metabolic profile. HFHC diet caused decreased hypothalamic glucocorticoid expression, which was further decreased in males compared to females. Maternal weight, maternal caloric intake, and male offspring meal frequency were inversely correlated with offspring hypothalamic insulin receptor (IR) expression. There was a significant interaction between maternal-diet exposure and sex in hypothalamic IR. Based on our preclinical data, we suggest that interventions focusing on normalizing maternal nutrition might be considered to attenuate nutritional influences on obesity programming and curb the continuing rise in obesity rates.

Malnourishment during early lactation disrupts the ontogenetic distribution of the CART and α-MSH anorexigenic molecules in the arcuate/paraventricular pathway and lateral hypothalamus in male rats

Developmental malnourishment impacts the energetic metabolism control throughout life. In rat offspring, a 0% protein diet during the first 10 days of lactation results in leptin resistance and in alterations in: feeding behavior, serum leptin and neuropeptide Y (NPY) levels in the hypothalamic arcuate nucleus (ARC)/paraventricular (PVN) pathway. Here, the distributions of alpha-melanocyte stimulating hormone (α-MSH) and cocaine and amphetamine regulated transcript (CART), anorexigenic molecules, were immunohistochemically assessed in the ARC, PVN and lateral hypothalamus (LH) nuclei. Rat dams were subjected to one of the following diet protocols from postnatal day (P) 1-10: 1) Protein-free (PFG, 0% protein chow); 2) Pair-fed (UFG, normoprotein chow); 3) Control group (CG, normoprotein chow). PFG, UFG and CG male offspring were analyzed at different time points, from P5 to P180. In the ARC, PFG α-MSH and CART were increased from P10 to P45 when compared to CG and UFG. In the PVN, α-MSH and CART peaks in PFG animals were delayed from P20 to P30 when compared to CG. In the LH, CART was more intense in PFG animals than in UFG and CG ones by P20, and, by P30, UFG immunostaining became less intense than in CG. In conclusion, aproteic diet altered the ontogenetic distribution of both anorexigenic molecules. In the PVN, the peak was delayed to P30, which coincides with the leptin peak and follows the previously described NPY (orexigenic) peak in this model. The permanent LH CART and α-MSH increase may be associated with the previously observed PFG hypophagia.

Differential Responses of Liver and Hypothalamus to the Nutritional Condition During Lactation and Adult Life

It was previously reported that liver glucose metabolism in rats under caloric restriction differs from that of freely-fed rats. This study hypothesized that these changes (1) were related to the expression of hypothalamic neuropeptides involved in metabolic control, and (2) were not a residual effect of litter size. To those purposes, liver glucose metabolism and hypothalamic expression of the orexigenic neuropeptides NPY (neuropeptide Y) and AgRP (agouti gene-related peptide); and of the anorexigenic neuropeptides POMC (pro-opiomelanocortin) and CART (cocaine- and amphetamine-related transcripts) were investigated. Male Wistar rats from two different litter sizes (G6 and G12, with 6 or 12 pups, respectively) were subjected to free feeding (GL, ad libitum), 50% caloric restriction (GR) or caloric restriction+ad libitum refeeding (GRL) until the age of 90 days. Biometric values were lower in GR than in GL, while in GRL they were totally or partially recovered. Blood glucose variation during the pyruvate tolerance test (PTT) was small in GR. During in situ liver perfusion, total, basal, and adrenaline-stimulated liver glucose outputs were high in GR, but additional glucose output in the presence of alanine was negligible. Refeeding (GRL) yielded values close to those of GL. Litter size did not consistently influence any of these variables. The expression of transcripts of the hypothalamic neuropeptides was responsive to feeding regimen, litter size and/or their interaction and differed from G6 to G12, while the metabolic changes of the liver were qualitatively equal in both GR. Therefore, the changes in glucose metabolism in the liver of rats under caloric restriction were not determined by either litter size or hypothalamic neuropeptide expression and were linked only to the prevailing feeding regimen of the adult animal.

Individual housing of male C57BL/6J mice after weaning impairs growth and predisposes for obesity

For (metabolic) research models using mice, singly housing is widely used for practical purposes to study e.g. energy balance regulation and derangements herein. Mouse (social) housing practices could however influence study results by modulating (metabolic) health outcomes. To study the effects of the social housing condition, we assessed parameters for energy balance regulation and proneness to (diet induced) obesity in male C57Bl/6J mice that were housed individually or socially (in pairs) directly after weaning, both at standard ambient temperature of 21°C. During adolescence, individually housed mice had reduced growth rate, while energy intake and energy expenditure were increased compared to socially housed counterparts. At 6 weeks of age, these mice had reduced lean body mass, but significantly higher white adipose tissue mass compared to socially housed mice, and higher UCP-1 mRNA expression in brown adipose tissue. During adulthood, body weight gain of individually housed animals exceeded that of socially housed mice, with elevations in both energy intake and expenditure. At 18 weeks of age, individually housed mice showed higher adiposity and higher mRNA expression of UCP-1 in inguinal white but not in brown adipose tissue. Exposure to an obesogenic diet starting at 6 weeks of age further amplified body weight gain and adipose tissue deposition and caused strong suppression of inguinal white adipose tissue mRNA UCP-1 expression. This study shows that post-weaning individual housing of male mice impairs adolescent growth and results in higher susceptibility to obesity in adulthood with putative roles for thermoregulation and/or affectiveness.

Maternal Protein Restriction in Rats Alters the Expression of Genes Involved in Mitochondrial Metabolism and Epitranscriptomics in Fetal Hypothalamus

Fetal brain development is closely dependent on maternal nutrition and metabolic status. Maternal protein restriction (PR) is known to be associated with alterations in the structure and function of the hypothalamus, leading to impaired control of energy homeostasis and food intake. The objective of this study was to identify the cellular and molecular systems underlying these effects during fetal development. We combined a global transcriptomic analysis on the fetal hypothalamus from a rat model of maternal PR with in vitro neurosphere culture and cellular analyses. Several genes encoding proteins from the mitochondrial respiratory chain complexes were overexpressed in the PR group and mitochondrial metabolic activity in the fetal hypothalamus was altered. The level of the N6-methyladenosine epitranscriptomic mark was reduced in the PR fetuses, and the expression of several genes involved in the writing/erasing/reading of this mark was indeed altered, as well as genes encoding several RNA-binding proteins. Additionally, we observed a higher number of neuronal-committed progenitors at embryonic day 17 (E17) in the PR fetuses. Together, these data strongly suggest a metabolic adaptation to the amino acid shortage, combined with the post-transcriptional control of protein expression, which might reflect alterations in the control of the timing of neuronal progenitor differentiation.

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.

Increased Hypothalamic Projections to the Lateral Hypothalamus and Responses to Leptin in Rat Neonates From High Fat Fed Mothers

The lateral hypothalamus (LHA) is a central hub in the regulation of food intake and metabolism, as it integrates homeostatic and hedonic circuits. During early development, maturing input to and output from the LHA might be particularly sensitive to environmental dietary changes. We examined the effects of a maternal high fat diet (HFD, 60% Kcal in fat) on the density of hypothalamic projections to the orexin (ORX-A) field of the LHA in 10 day-old (PND10) rat pups using retrograde labeling with fluorescent microspheres. We also compared responsiveness of phenotypically identified LHA neurons to leptin administration (3 mg/kg, bw) between pups from control (CD) or high fat (HFD) fed mothers on PND10 and 15-16, at the onset of independent feeding. HFD pups exhibited a higher density of LHA projections (p = 0.05) from the ventromedial hypothalamus (VMH) compared to CD pups and these originated from both SF-1 and BDNF-positive neurons in the VMH. Increased circulating leptin levels in HFD pups, particularly on PND15-16 was consistent with enhanced pSTAT3 responses to leptin in the orexin (ORX-A) field of the LHA, with some of the activated neurons expressing a GABA, but not CART phenotype. ORX-A neurons colocalizing with pERK were significantly higher in PND15-16 HFD pups compared to CD pups, and leptin-induced increase in pERK signaling was only observed in CD pups. There was no significant effect of leptin on pERK in HFD pups. These results suggest that perinatal maternal high fat feeding increases hypothalamic projections to the ORX-A field of the LHA, increases basal activation of ORX-A neurons and direct responsiveness of LHA neurons to leptin. Since these various LHA neuronal populations project quite heavily to Dopamine (DA) neurons in the ventral tegmental area, they might participate in the early dietary programming of mesocorticolimbic reward circuits and food intake.

Modulation of liver glucose output by free or restricted feeding in the adult rat is independent of litter size

Background

Caloric restriction since birth changes glucose metabolism by the liver in overnight-fasted rats to a fed-like pattern, in which glucose output is large but gluconeogenesis is negligible. It was investigated whether these changes could be a residual effect of the nutritional condition during lactation and what could be the mechanism of such change.

Methods

Newborn Wistar rat pups were arranged in litters of 6 or 12 (G6 and G12). After weaning, the male pups were divided in: G6L and G12 L, fed freely until the age of 90 days (freely-fed groups); G6R and G12R, given 50% of the GL ingestion (food-restricted groups) until 90 days of age; G6RL and G12RL, given 50% of the GL ingestion until 60 days of age and fed freely until 90 days of age (refed groups). The experimental protocols were carried out at the age of 90 days after overnight fasting. Pairs of groups were compared through t test; other statistical comparisons were made with one-way ANOVA with Tukey post hoc text.

Results

Caloric restriction was effective in decreasing body and fat weights, total cholesterol and LDL. These effects were totally or partially reversed after 30 days of refeeding (groups GRL). During liver perfusion, the high glucose output of the GRs was further enhanced by adrenaline (1 μM), but not by lactate infusion. In contrast, in groups G6L, G12 L, G6RL and G12RL glycogenolysis (basal and adrenaline-stimulated glucose output) was low and gluconeogenesis from lactate was significant. A twofold increase in liver content of PKA in group G6R suggests that liver sensitivity to glucagon and adrenaline was higher because of caloric restriction, resulting in enhanced glucose output.

Conclusions

As glucose output was not affected by litter size, liver glucose metabolism in the adult rat, in contrast to other metabolic processes, is not a programmed effect of the nutritional condition during lactation. In addition, the increased expression of PKA points to a higher sensitivity of the animals under caloric restriction to glycogenolytic hormones, a relevant condition for glucose homeostasis during fasting.

Epigenetics: Linking Early Postnatal Nutrition to Obesity Programming?

Despite constant research and public policy efforts, the obesity epidemic continues to be a major public health threat, and new approaches are urgently needed. It has been shown that nutrient imbalance in early life, from conception to infancy, influences later obesity risk, suggesting that obesity could result from "developmental programming". In this review, we evaluate the possibility that early postnatal nutrition programs obesity risk via epigenetic mechanisms, especially DNA methylation, focusing on four main topics: (1) the dynamics of epigenetic processes in key metabolic organs during the early postnatal period; (2) the epigenetic effects of alterations in early postnatal nutrition in animal models or breastfeeding in humans; (3) current limitations and remaining outstanding questions in the field of epigenetic programming; (4) candidate pathways by which early postnatal nutrition could epigenetically program adult body weight set point. A particular focus will be given to the potential roles of breast milk fatty acids, neonatal metabolic and hormonal milieu, and gut microbiota. Understanding the mechanisms by which early postnatal nutrition can promote lifelong metabolic modifications is essential to design adequate recommendations and interventions to "de-program" the obesity epidemic.

Cortisol, leptin and free leptin index (FLI) in newborns in the first days of life and their importance for body weight programming

BACKGROUND

Birth weight and leptin seem to be the factors responsible for early programming of body weight in later life. A marker for leptin action is free leptin index (FLI), which depends on soluble leptin receptor (Ob-Re) (FLI = leptin/Ob-Re). In the present article, we suggest that FLI is modulated partly by cortisol variations observed in newborns in the first days of life and is connected with their postnatal weight loss.

METHODS

The study group consisted of 44 full-term newborns. Leptin, cortisol and Ob-Re concentrations were determined in the umbilical cord blood (UCB) and in the newborns' blood (NB) on the fourth day of life, free leptin index (FLI = leptin/Ob-Re) was calculated. Correlations between the assessed parameters and the somatic features of the newborns were examined.

RESULTS

Birth weight, length and chest circumference of newborns were positively correlated with leptin concentration in the UCB but not with FLI in the UCB. Cortisol and leptin concentrations, as well as FLI values declined concomitantly with body weight, and were lower on the fourth day of life than on the first one; however, Ob-Re concentration increased (p < 0.0001). There was a positive correlation between the newborns' birth weight loss percentage evaluated on the fourth day of life and FLI in newborns (R = 0.39; p < 0.01). Positive correlations between cortisol and Ob-Re in UCB (R = 0.35; p < 0.02) and in NB (R = 0.36; p < 0.01), as well as a negative correlation between cortisol and FLI (R = -0.32; p < 0.03) in NB were noted.

CONCLUSIONS

Our data suggest a possible relationship between cortisol and a soluble leptin receptor (Ob-Re), which changes free leptin index (FLI) and is connected with birth weight loss in newborns. Whether these observations are important for programming of future body weight of children requires further research.

Potential attenuation of early-life overfeeding-induced metabolic dysfunction by chronic maternal acetylcholinesterase inhibitor exposure

Evidence suggests that low concentration perinatal exposure to environmental contaminants, such as organophosphate (OP) is associated with later life insulin resistance and type 2 diabetes. The aim of this work was to investigate whether chronic maternal OP exposure exacerbates metabolic dysfunctions in early-overfed rats. During pregnancy and lactational periods, dams received OP by gavage. To induce neonatal overnutrition at postnatal day 3, pups were standardized to 9 or 3 per nest. At 90-days-old, glucose-insulin homeostasis and insulin release from pancreatic islets were analyzed. While both OP exposure and overfeeding alone did induce diabetogenic phenotypes in adulthood, there was no exacerbation in rats that experienced both. Unexpectedly, the group that experienced both had improved adiposity, metabolic parameters, attenuated insulin release from isolated islets in the presence of glucose and low function of muscarinic acetylcholine receptor M3, as well as an attenuation of beta cell mass hyperplasia. High levels of butyrylcholinesterase and low levels of insulin in milk may contribute to the OP-induced developmental programming. Our study showed that maternal OP exposure may program insulin release as well as endocrine pancreas structure, thus affecting metabolism in adulthood. Our data suggest that while perinatal OP exposure alone increases the risk for later life T2D, it actually reverses many of the programmed metabolic dysfunction that is induced by postnatal overfeeding. These surprising results may suggest that low-dose administration of acetylcholinesterase inhibitors could be of utility in preventing detrimental developmental programming that is caused by early-life overnutrition.

Fetal and Infancy Growth Pattern, Cord and Early Childhood Plasma Leptin, and Development of Autism Spectrum Disorder in the Boston Birth Cohort

Leptin is a proinflammatory cytokine that plays an important role in energy homeostasis. Emerging evidence suggests that leptin levels are altered in children with autism spectrum disorder (ASD); however, this has not been studied prospectively. Rapid growth during infancy and early childhood has been implicated in ASD, but the evidence is inconsistent. As leptin is involved in growth and is a potential risk factor for ASD, we explored the associations between (a) cord, early childhood leptin and ASD; and (b) birth weight for gestational age, early childhood weight gain, and ASD. We also assessed the mediating role of leptin in the relationship between weight gain during infancy and ASD. This study was conducted in a sample of 822 subjects from the Boston Birth Cohort. ASD was defined from diagnostic codes in electronic medical records. Extremely rapid weight gain during infancy was associated with a greater ASD risk and this persisted after adjusting for potential confounders (aOR: 3.11; 95% CI: 1.37, 7.07). Similarly, children that had higher plasma leptin levels, prior to ASD diagnosis, had an increased ASD risk in both unadjusted and adjusted models (aOR: 7.87; 95% CI: 2.06, 30.04). Further, early childhood leptin indirectly mediated the relationship between rapid weight gain and ASD. No associations were found between birth weight for gestational age, cord leptin and risk of ASD. Our findings provide a basis to further explore whether the combination of early life growth pattern and a biomarker such as leptin can predict ASD earlier. Autism Res 2018, 11: 1416-1431. © 2018 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: Is early life growth and a biomarker leptin related to ASD risk? To answer this question, we followed 822 children from birth and found that those who gained weight very quickly in infancy, had higher leptin levels in early childhood, had a greater chance of later ASD diagnosis. More research is needed to see if infant's weight gain pattern along with a biomarker (such as leptin) can be used to identify children with ASD sooner.

Neonatal overfeeding increases capacity for catecholamine biosynthesis from the adrenal gland acutely and long-term in the male rat

A poor nutritional environment during early development has long been known to increase disease susceptibility later in life. We have previously shown that rats that are overfed as neonates (i.e. suckled in small litters (4 pups) relative to control conditions (12 pups)) show dysregulated hypothalamic-pituitary-adrenal axis responses to immune stress in adulthood, particularly due to an altered capacity of the adrenal to respond to an immune challenge. Here we hypothesised that neonatal overfeeding similarly affects the sympathomedullary system, testing this by investigating the biochemical function of tyrosine hydroxylase (TH), the first rate-limiting enzyme in the catecholamine synthesis. We also examined changes in adrenal expression of the leptin receptor and in mitogen-activated protein kinase (MAPK) signalling. During the neonatal period, we saw age-dependent changes in TH activity and phosphorylation, with neonatal overfeeding stimulating increased adrenal TH specific activity at postnatal days 7 and 14, along with a compensatory reduction in total TH protein levels. This increased TH activity was maintained into adulthood where neonatally overfed rats exhibited increased adrenal responsiveness 30 min after an immune challenge with lipopolysaccharide, evident in a concomitant increase in TH protein levels and specific activity. Neonatal overfeeding significantly reduced the expression of the leptin receptor in neonatal adrenals at postnatal day 7 and in adult adrenals, but did not affect MAPK signalling. These data suggest neonatal overfeeding alters the capacity of the adrenal to synthesise catecholamines, both acutely and long term, and these effects may be independent of leptin signalling.

The impact of androgen actions in neurons on metabolic health and disease

The male hormone testosterone exerts different effects on glucose and energy homeostasis in males and females. Testosterone deficiency predisposes males to visceral obesity, insulin resistance and type 2 diabetes. However, testosterone excess predisposes females to similar metabolic dysfunction. Here, we review the effects of testosterone actions in the central nervous system on metabolic function in males and females. In particular, we highlight changes within the hypothalamus that control glucose and energy homeostasis. We distinguish the organizational effects of testosterone in the programming of neural circuitry during development from the activational effects of testosterone during adulthood. Finally, we explore potential sites where androgen might be acting to impact metabolism within the central nervous system.

Impact of maternal high fat diet on hypothalamic transcriptome in neonatal Sprague Dawley rats

Maternal consumption of a high fat diet during early development has been shown to impact the formation of hypothalamic neurocircuitry, thereby contributing to imbalances in appetite and energy homeostasis and increasing the risk of obesity in subsequent generations. Early in postnatal life, the neuronal projections responsible for energy homeostasis develop in response to appetite-related peptides such as leptin. To date, no study characterises the genome-wide transcriptional changes that occur in response to exposure to high fat diet during this critical window. We explored the effects of maternal high fat diet consumption on hypothalamic gene expression in Sprague Dawley rat offspring at postnatal day 10. RNA-sequencing enabled discovery of differentially expressed genes between offspring of dams fed a high fat diet and offspring of control diet fed dams. Female high fat diet offspring displayed altered expression of 86 genes (adjusted P-value<0.05), including genes coding for proteins of the extra cellular matrix, particularly Collagen 1a1 (Col1a1), Col1a2, Col3a1, and the imprinted Insulin-like growth factor 2 (Igf2) gene. Male high fat diet offspring showed significant changes in collagen genes (Col1a1 and Col3a1) and significant upregulation of two genes involved in regulation of dopamine availability in the brain, tyrosine hydroxylase (Th) and dopamine reuptake transporter Slc6a3 (also known as Dat1). Transcriptional changes were accompanied by increased body weight, body fat and body length in the high fat diet offspring, as well as altered blood glucose and plasma leptin. Transcriptional changes identified in the hypothalamus of offspring of high fat diet mothers could alter neuronal projection formation during early development leading to abnormalities in the neuronal circuitry controlling appetite in later life, hence priming offspring to the development of obesity.

Smell and taste in the preterm infant

Olfaction and gustation are critical for the enjoyment of food but also have important metabolic roles, initiating the cephalic phase response that sets in train secretion of hormones important for metabolism and digestion before any food is actually ingested. Smell and taste receptors are functional in the fetus and there is evidence for antenatal learning of odours. Despite enteral nutrition and metabolism being major issues in the care of very preterm infants, often little consideration is given to the potential role of smell and taste in supporting these processes, or in the role they may have in encoding hypothalamic circuitry in a way that promotes healthy metabolism in the post‑neonatal period. This review will discuss the evidence for the role of smell and taste in the newborn infant.

Activity Dependent Modulation of Granule Cell Survival in the Accessory Olfactory Bulb at Puberty

The vomeronasal system (VNS) is specialized in the detection of salient chemical cues triggering social and neuroendocrine responses. Such responses are not always stereotyped, instead, they vary depending on age, sex, and reproductive state, yet the mechanisms underlying this variability are unclear. Here, by analyzing neuronal survival in the first processing nucleus of the VNS, namely the accessory olfactory bulb (AOB), through multiple bromodeoxyuridine birthdating protocols, we show that exposure of female mice to male soiled bedding material affects the integration of newborn granule interneurons mainly after puberty. This effect is induced by urine compounds produced by mature males, as bedding soiled by younger males was ineffective. The granule cell increase induced by mature male odor exposure is not prevented by pre-pubertal ovariectomy, indicating a lesser role of circulating estrogens in this plasticity. Interestingly, the intake of adult male urine-derived cues by the female vomeronasal organ increases during puberty, suggesting a direct correlation between sensory activity and AOB neuronal plasticity. Thus, as odor exposure increases the responses of newly born cells to the experienced stimuli, the addition of new GABAergic inhibitory cells to the AOB might contribute to the shaping of vomeronasal processing of male cues after puberty. Consistently, only after puberty, female mice are capable to discriminate individual male odors through the VNS.

Involvement of the CXCL12 System in the Stimulatory Effects of Prenatal Exposure to High-Fat Diet on Hypothalamic Orexigenic Peptides and Behavior in Offspring

Exposure to a high fat diet (HFD) during gestation stimulates neurogenesis and expression of hypothalamic orexigenic neuropeptides that affect consummatory and emotional behaviors. With recent studies showing a HFD to increase inflammation, this report investigated the neuroinflammatory chemokine, CXCL12, and compared the effects of prenatal CXCL12 injection to those of prenatal HFD exposure, first, by testing whether the HFD affects circulating CXCL12 in the dam and the CXCL12 system in the offspring brain, and then by examining whether prenatal exposure to CXCL12 itself mimics the effects of a HFD on hypothalamic neuropeptides and emotional behaviors. Our results showed that prenatal exposure to a HFD significantly increased circulating levels of CXCL12 in the dam, and that daily injections of CXCL12 induced a similar increase in CXCL12 levels as the HFD. In addition, prenatal HFD exposure significantly increased the expression of CXCL12 and its receptors, CXCR4 and CXCR7, in the hypothalamic paraventricular nucleus (PVN) of the offspring. Finally, the results revealed strong similarities in the effects of prenatal HFD and CXCL12 administration, which both stimulated neurogenesis and enkephalin (ENK) expression in the PVN, while having inconsistent or no effect in other regions of the hypothalamus, and also increased anxiety as measured by several behavioral tests. These results focus attention specifically on the CXCL12 chemokine system in the PVN of the offspring as being possibly involved in the stimulatory effects of prenatal HFD exposure on ENK-expressing neurons in the PVN and their associated changes in emotional behavior.

Non-Neuronal Cells in the Hypothalamic Adaptation to Metabolic Signals

Although the brain is composed of numerous cell types, neurons have received the vast majority of attention in the attempt to understand how this organ functions. Neurons are indeed fundamental but, in order for them to function correctly, they rely on the surrounding "non-neuronal" cells. These different cell types, which include glia, epithelial cells, pericytes, and endothelia, supply essential substances to neurons, in addition to protecting them from dangerous substances and situations. Moreover, it is now clear that non-neuronal cells can also actively participate in determining neuronal signaling outcomes. Due to the increasing problem of obesity in industrialized countries, investigation of the central control of energy balance has greatly increased in attempts to identify new therapeutic targets. This has led to interesting advances in our understanding of how appetite and systemic metabolism are modulated by non-neuronal cells. For example, not only are nutrients and hormones transported into the brain by non-neuronal cells, but these cells can also metabolize these metabolic factors, thus modifying the signals reaching the neurons. The hypothalamus is the main integrating center of incoming metabolic and hormonal signals and interprets this information in order to control appetite and systemic metabolism. Hence, the factors transported and released from surrounding non-neuronal cells will undoubtedly influence metabolic homeostasis. This review focuses on what is known to date regarding the involvement of different cell types in the transport and metabolism of nutrients and hormones in the hypothalamus. The possible involvement of non-neuronal cells, in particular glial cells, in physiopathological outcomes of poor dietary habits and excess weight gain are also discussed.

Programming of Adiposity in Childhood and Adolescence: Associations With Birth Weight and Cord Blood Adipokines

CONTEXT

Exposure to maternal adiposity during pregnancy is associated with higher offspring birth weight and greater adiposity through childhood and adult life. As birth weight reflects the summation of lean and fat mass, the extent to which fat mass at birth tracks into later life is unknown.

OBJECTIVE

To determine whether fat mass at birth is associated with child and adolescent adiposity.

DESIGN, SETTING, AND PARTICIPANTS

UK birth cohort with markers of neonatal fat mass; cord blood leptin, adiponectin, and birth weight and adiposity outcomes at age 9 (n = 2775) and 17 years (n = 2138).

MAIN OUTCOMES

Offspring body mass index (BMI), waist circumference, dual-energy X-ray absorptiometry-determined fat mass, and obesity at age 9 and 17 years.

RESULTS

Higher cord blood leptin was associated with higher z scores of fat mass [difference in mean per 10 pg/mL: 0.03 standard deviation (SD); 95% confidence interval (CI), 0.00 to 0.06], waist circumference (0.04 SD; 95% CI, 0.00 to 0.07), and BMI (0.04 SD; 95% CI, 0.00 to 0.08) at age 9. However, by age 17 the adjusted results were attenuated to the null. Cord blood adiponectin was not associated with measures of adiposity at age 9. At age 17, cord blood adiponectin was positively associated with fat mass (0.02 SD per 10 μg/mL; 95% CI, 0.02 to 0.03) and waist circumference (0.04 SD per 10 μg/mL; 95% CI, 0.03 to 0.05). Birth weight was positively associated with waist circumference (0.03 SD per 100 g; 95% CI, 0.02 to 0.04) and BMI (0.02 SD per 100 g; 95% CI, 0.00 to 0.03), but not fat mass or odds of obesity. Cord blood leptin and adiponectin were not associated with obesity at either age.

CONCLUSIONS

Increased cord blood leptin and adiponectin, known surrogates of fetal fat mass, were weakly associated with increased fat mass in late childhood and adolescence, respectively.

Effects of maternal obesity on placental function and fetal development

Obesity has reached epidemic proportions, and pregnancies in obese mothers have increased risk for complications including gestational diabetes, hypertensive disorders, pre-term birth and caesarian section. Children born to obese mothers are at increased risk of obesity and metabolic disease and are susceptible to develop neuropsychiatric and cognitive disorders. Changes in placental function not only play a critical role in the development of pregnancy complications but may also be involved in linking maternal obesity to long-term health risks in the infant. Maternal adipokines, i.e., interleukin 6 (IL-6), tumor necrosis factor alpha (TNF-α), leptin and adiponectin link maternal nutritional status and adipose tissue metabolism to placental function. Adipokines and metabolic hormones have direct impact on placental function by modulating placental nutrient transport. Nutrient delivery to the fetus is regulated by a complex interaction including insulin signaling, cytokine profile and insulin responsiveness, which is modulated by adiponectin and IL-1β. In addition, obese pregnant women are at risk for hypertension and preeclampsia with reduced placental vascularity and blood flow, which would restrict placental nutrient delivery to the developing fetus. These sometimes opposing signals regulating placental function may contribute to the diversity of short and long-term outcomes observed in pregnant obese women. This review focuses on the changes in adipokines and obesity-related metabolic hormones, how these factors influence placental function and fetal development to contribute to long-term metabolic and behavioral consequences of children born to obese mothers.