Leptin in early life: a key factor for the development of the adult metabolic profile

Minireview: Glucocorticoid-Leptin Crosstalk: Role of Glucocorticoid-Leptin Counterregulation in Metabolic Homeostasis and Normal Development

Glucocorticoids and leptin are two important hormones that regulate metabolic homeostasis by controlling appetite and energy expenditure in adult mammals. Also, glucocorticoids and leptin strongly counterregulate each other, such that chronic stress-induced glucocorticoids upregulate the production of leptin and leptin suppresses glucocorticoid production directly via action on endocrine organs and indirectly via action on food intake. Altered glucocorticoid or leptin levels during development can impair organ development and increase the risk of chronic diseases in adults, but there are limited studies depicting the significance of glucocorticoid-leptin interaction during development and its impact on developmental programming. In mammals, leptin-induced suppression of glucocorticoid production is critical during development, where leptin prevents stress-induced glucocorticoid production by inducing a period of short-hyporesponsiveness when the adrenal glands fail to respond to certain mild to moderate stressors. Conversely, reduced or absent leptin signaling increases glucocorticoid levels beyond what is appropriate for normal organogenesis. The counterregulatory interactions between leptin and glucocorticoids suggest the potential significant involvement of leptin in disorders that occur from stress during development.

The Metabolically Obese, Normal-Weight Phenotype in Young Rats Is Associated with Cognitive Impairment and Partially Preventable with Leptin Intake during Lactation

The intake of high-fat diets (HFDs) and obesity are linked to cognitive impairment. Here, we aimed to investigate whether an early metabolically obese, normal-weight (MONW) phenotype, induced with an HFD in young rats, also leads to cognitive dysfunction and to evaluate the potential cognitive benefits of neonatal intake of leptin. To achieve this, Wistar rats orally received physiological doses of leptin or its vehicle during lactation, followed by 11 weeks of pair-feeding with an HFD or control diet post-weaning. Working memory was assessed using a T-maze, and gene expression in the hippocampus and peripheral blood mononuclear cells (PBMCs) was assessed with real-time RT-qPCR to identify cognition biomarkers. Young MONW-like rats showed hippocampal gene expression changes and decreased working memory. Animals receiving leptin during lactation presented similar gene expression changes but preserved working memory despite HFD intake, partly due to improved insulin sensitivity. Notably, PBMC Syn1 expression appears as an accessible biomarker of cognitive health, reflecting both the detrimental effect of HFD intake at early ages despite the absence of obesity and the positive effects of neonatal leptin treatment on cognition. Thus, the MONW phenotype developed at a young age is linked to cognitive dysfunction, which is reflected at the transcriptomic level in PBMCs. Neonatal leptin intake can partly counteract this impaired cognition resulting from early HFD consumption.

Dam Body Condition Score Alters Offspring Circulating Cortisol and Energy Metabolites in Holstein Calves but Did Not Affect Neonatal Leptin Surge

The neonatal leptin surge is important for hypothalamic development, feed intake regulation, and long-term metabolic control. In sheep, the leptin surge is eliminated with maternal overnutrition and an elevated dam body condition score (BCS), but this has not been assessed in dairy cattle. The aim of this study was to characterize the neonatal profile of leptin, cortisol and other key metabolites in calves born to Holstein cows with a range of BCS. Dam BCS was determined 21 d before expected parturition. Blood was collected from calves within 4 h of birth (d 0), and on days 1, 3, 5, and 7. Serum was analyzed for concentrations of leptin, cortisol, blood urea nitrogen, β-hydroxybutyrate (BHB), free fatty acids (FFA), triglycerides, and total protein (TP). Statistical analysis was performed separately for calves sired by Holstein (HOL) or Angus (HOL-ANG) bulls. Leptin tended to decrease after birth in HOL calves, but there was no evidence of an association between leptin and BCS. For HOL calves, the cortisol level increased with an increasing dam BCS on day 0 only. Dam BCS was variably associated with the calf BHB and TP levels, depending on the sire breed and day of age. Further investigation is required to elucidate the impacts of maternal dietary and energy status during gestation on offspring metabolism and performance, in addition to the potential impact of the absence of a leptin surge on long-term feed intake regulation in dairy cattle.

Paternal dietary ratio of n-6: n-3 polyunsaturated fatty acids programs offspring leptin expression and gene imprinting in mice

Background

This study determined the effects of the paternal dietary ratio of n-6: n-3 polyunsaturated fatty acids (PUFAs) on leptin expression in the offspring and associated gene imprinting in a mouse model.

Methods

Three- to four-week-old male C57BL/6J mice (F0) were fed an n-3 PUFA-deficient (n-3 D) diet, a diet with normal n-3 PUFA content (n-3 N; n-6: n-3 = 4.3:1), or a diet with a high n-3 PUFA content (n-3 H; n-6: n-3 = 1.5:1) for 8 weeks. Two subsequent generations were generated by mating F0 and F1 male mice with 10-week-old virgin female C57 BL/6J mice, to produce F1 and F2 offspring.

Results

Compared to the paternal n-3 D diet, paternal n-3 N and n-3 H diets reduced adipose mRNA expression of leptin (Lep) and its plasma concentrations in juvenile F1 male and female offspring, and adult F1 male and F2 female offspring, with upregulated Lep receptor mRNA expression in the hypothalamus. Meanwhile, paternal n-3 N and n-3 H diets altered the expression of the imprinted genes H19, Igf2, Igf2r, Plagl1, Cdkn1c, Kcnq1ot1, Peg3, and Grb10 in the adipose tissue of juvenile and adult F1 males, with almost no effects on F1 females, while more effects were observed in the adult F2 females than F2 males. Principal component analysis verified that Plagl1, Cdkn1c, and Kcnq1ot1 contributed the most to variation in adipose tissue expression in all offspring. Some of these genes (Plagl1, Cdkn1c, Kcnq1ot1, Peg3, and Grb10) were altered by the paternal n-3 N and n-3 H diets in the F1 and F2 generation testes as well. Furthermore, adipose Lep expression was positively correlated with expressions of H19, Igf2r, Plagl1, and Kcnq1ot1 in juvenile F1 males and females, negatively correlated with the Kcnq1ot1 expression in adult F1 males, and positively correlated with the Plagl1 expression in adult F2 females.

Conclusion

These data imply that paternal Plagl1, Cdkn1c, and Kcnq1ot1 might be part of the pathways involved in offspring leptin programming. Therefore, a lower ratio of n-6: n-3 PUFAs, with higher intake of n-3 PUFAs in paternal pre-conception, may help maintain the offspring's optimal leptin pattern in a sex-specific manner through multiple generations, and thereby, be beneficial for the offspring's long-term health.

Neonatal leptin antagonism improves metabolic programming of postnatally overnourished mice

BACKGROUND/OBJECTIVES

Alteration of the perinatal nutritional environment is an important risk factor for the development of metabolic diseases in later life. The hormone leptin plays a critical role in growth and development. Previous studies reported that postnatal overnutrition increases leptin secretion during the pre-weaning period. However, a direct link between leptin, neonatal overnutrition, and lifelong metabolic regulation has not been investigated.

METHODS

We used the small litter mouse model combined with neonatal leptin antagonist injections to examine whether attenuating leptin during early life improves lifelong metabolic regulation in postnatally overnourished mice.

RESULTS

Postnatally overnourished mice displayed rapid weight gain during lactation and remained overweight as adults. These mice also showed increased adiposity and perturbations in glucose homeostasis in adulthood. Neonatal administration of a leptin antagonist normalized fat mass and insulin sensitivity in postnatally overnourished mice. These metabolic improvements were associated with enhanced sensitivity of hypothalamic neurons to leptin.

CONCLUSIONS

Early postnatal overnutrition causes metabolic alterations that can be permanently attenuated with the administration of a leptin antagonist during a restricted developmental window.

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.

Leptin administration during lactation leads to different nutritional, biometric, hemodynamic, and cardiac outcomes in prepubertal and adult female Wistar rats

Literature reports that insults, such as hormonal disturbances, during critical periods of development may modulate organism physiology and metabolism favoring cardiovascular diseases (CVDs) later in life. Studies show that leptin administration during lactation leads to cardiovascular dysfunction in young and adult male Wistar rats. However, there are sex differences regarding CVD. Thus, the present work aimed to investigate neonatal leptin administration's consequences on different outcomes in female rats at prepubertal and adult age. Newborn Wistar female rats were divided into two groups, Leptin and Control, receiving daily subcutaneous injections of this adipokine (8 μg/100 g) or saline for the first 10 of 21 d of lactation. Nutritional, biometric, hemodynamic, and echocardiographic parameters, as well as maximal effort ergometer performance, were determined at postnatal days (PND) 30 and 150. Leptin group presented lower food intake (p = 0.0003) and higher feed efficiency (p = 0.0058) between PND 21 and 30. Differences concerning echocardiographic parameters revealed higher left ventricle internal diameter (LVID) in systole (p = 0.0051), as well as lower left ventricle ejection fraction (LVEF) (p = 0.0111) and fractional shortening (FS) (p = 0.0405) for this group at PND 30. Older rats treated with leptin during lactation presented only higher LVID in systole (p = 0.0270). Systolic blood pressure and maximum effort ergometer test performance was similar between groups at both ages. These data suggest that nutritional, biometric, and cardiac outcomes due to neonatal leptin administration in female rats are age-dependent.

Sex and Exposure to Postnatal Chlorpyrifos Influence the Epigenetics of Feeding-Related Genes in a Transgenic APOE Mouse Model: Long-Term Implications on Body Weight after a High-Fat Diet

Developmental exposure to toxicants and diet can interact with an individual's genetics and produce long-lasting metabolic adaptations. The different isoforms of the apolipoprotein E (APOE) are an important source of variability in metabolic disorders and influence the response to the pesticide chlorpyrifos (CPF). We aimed to study the epigenetic regulation on feeding control genes and the influence of postnatal CPF exposure, APOE genotype, and sex, and how these modifications impact on the metabolic response to a high-fat diet (HFD). Both male and female apoE3- and apoE4-TR mice were exposed to CPF on postnatal days 10-15. The DNA methylation pattern of proopiomelanocortin, neuropeptide Y, leptin receptor, and insulin-like growth factor 2 was studied in the hypothalamus. At adulthood, the mice were given a HFD for eight weeks. The results highlight the importance of sex in the epigenetic regulation and the implication of CPF treatment and APOE genotype. The body weight progression exhibited sex-dimorphic differences, apoE4-TR males being the most susceptible to the effects induced by CPF and HFD. Overall, these results underscore the pivotal role of sex, APOE genotype, and developmental exposure to CPF on subsequent metabolic disturbances later in life and show that sex is a key variable in epigenetic regulation.

Leptin partially mediates the association between early-life nutritional supplementation and long-term glycemic status among women in a Guatemalan longitudinal cohort

BACKGROUND

Early-life exposure to improved nutrition is associated with decreased risk of diabetes but increased risk of obesity. Leptin positively correlates with adiposity and has glucose-lowering effects, thus it may mediate the association of early-life nutrition and long-term glycemic status.

OBJECTIVES

We aimed to investigate the role of leptin in the differential association between early-life nutrition and the risks of obesity and diabetes.

METHODS

We analyzed data from a Guatemalan cohort who were randomly assigned at the village level to receive nutritional supplements as children. We conducted mediation analysis to examine the role of leptin in the associations of early-life nutrition and adult cardiometabolic outcomes.

RESULTS

Among 1112 study participants aged (mean ± SD) 44.1 ± 4.2 y, 60.6% were women. Cardiometabolic conditions were common: 40.2% of women and 19.4% of men were obese, and 53.1% of women and 41.0% of men were hyperglycemic or diabetic. Median (IQR) leptin concentration was 15.2 ng/mL (10.2-17.3 ng/mL) in women and 2.7 ng/mL (1.3-5.3 ng/mL) in men. Leptin was positively correlated with BMI (Spearman's ρ was 0.6 in women, 0.7 in men). Women exposed to improved nutrition in early life had 2.8-ng/mL (95% CI: 0.3, 5.3 ng/mL) higher leptin and tended to have lower fasting glucose (-0.8 mmol/L; -1.8, 0.2 mmol/L, nonsignificant) than unexposed women. There were no significant differences in leptin (-0.7 ng/mL; -2.1, 0.8 ng/mL) or fasting glucose (0.2 mmol/L; -0.5, 0.9 mmol/L) in men exposed to improved nutrition in early life compared with unexposed men. Leptin mediated 34.9% of the pathway between early-life nutrition and fasting glucose in women. The mediation in women was driven by improved pancreatic β-cell function. We did not observe the mediation effect in men.

CONCLUSIONS

Leptin mediated the glucose-lowering effect of early-life nutrition in women but not in men.

Weaning Holstein Calves at 17 Weeks of Age Enables Smooth Transition from Liquid to Solid Feed

Development of calves depends on prenatal and postnatal conditions. Primiparous cows were still maturing during pregnancy, which can lead to negative intrauterine conditions and affect the calf's metabolism. It is hypothesized that weaning calves at higher maturity has positive effects due to reduced metabolic stress. We aimed to evaluate effects of mothers' parity and calves' weaning age on growth performance and blood metabolites. Fifty-nine female Holstein calves (38.8 ± 5.3 kg birth weight, about 8 days old) were used in a 2 × 2 factorial experiment with factors weaning age (7 vs. 17 weeks) and parity of mother (primiparous vs. multiparous cows). Calves were randomly assigned one of these four groups. Live weight, live weight gain and morphometry increased over time and were greater in calves weaned later. Metabolic indicators except total protein were interactively affected by time and weaning age. Leptin remained low in early-weaned calves born to primiparous cows, while it increased in the other groups. The results suggest that weaning more mature calves has a positive effect on body growth, and calves born to primiparous cows particularly benefit from this weaning regimen. It also enables a smooth transition from liquid to solid feed, which might reduce the associated stress of weaning.

Postnatal administration of leptin antagonist mitigates susceptibility to obesity under high-fat diet in male αMUPA mice

Perturbations in postnatal leptin signaling have been associated with altered susceptibility to diet-induced obesity (DIO) under high-fat-diet (HFD), albeit with contradicting evidence. Previous studies have shown that alpha murine urokinase-type plasminogen activator (αMUPA) mice have a higher and longer postnatal leptin surge compared with their wild types (WTs) as well as lower body weight and food intake under regular diet (RD). Here we explored αMUPA's propensity for DIO and the effect of attenuating postnatal leptin signaling with leptin antagonist (LA) on energy homeostasis under both RD and HFD. Four-day-old αMUPA pups were treated on alternate days until postnatal day 18 with either vehicle or LA (10 or 20 mg·day^-1·kg^-1) and weaned into RD or HFD. Compared with RD-fed αMUPA males, HFD-fed αMUPA males showed higher energy intake, even when corrected for body weight difference, and became hyperinsulinemic and obese. Additionally, HFD-fed αMUPA males gained body weight at a higher rate than their WTs mainly because of strain differences in energy expenditure. LA administration did not affect strain differences under RD but attenuated αMUPA's hyperinsulinemia and DIO under HFD, most likely by mediating energy expenditure. Together with our previous findings, these results suggest that αMUPA's leptin surge underlies its higher susceptibility to obesity under HFD, highlighting the role of leptin-related developmental processes in inducing obesity in a postweaning obesogenic environment, at least in αMUPA males. This study therefore supports the use of αMUPA mice for elucidating developmental mechanisms of obesity and the efficacy of early-life manipulations via leptin surge axis in attenuating DIO.

Enhancement of immune maturation in suckling rats by leptin and adiponectin supplementation

Leptin and adiponectin, adipokines present in breast milk, have shown immunomodulatory properties. The current study aimed to ascertain whether a nutritional supplementation with leptin or adiponectin in neonatal rats was able to influence the maturation of the systemic immune response in early life. To achieve this, suckling Wistar rats were supplemented with either leptin (0.7 μg/kg/day) or adiponectin (35 μg/kg/day) during the whole suckling period. Plasmatic immunoglobulins were quantified, and spleen lymphocyte composition and their ability to proliferate and release cytokines were evaluated during (day 14) and at the end (day 21) of the suckling period. Rats fed with either adipokine showed higher plasma IgM and IgG1 concentrations and adiponectin supplementation also increased IgG2a at both studied days (P < 0.05). With regard to the lymphocyte composition, both adipokine supplementations increased T cell proportion and both CD4⁺ and CD8⁺ T cell subsets after two weeks of supplementation (P < 0.05). Moreover, only leptin administration increased NK and NKT cell proportions at the end of the suckling period. Finally, both adipokines influenced the cytokine secretion pattern by splenocytes. In conclusion, these results suggest that leptin and adiponectin play a role in the maturation of the systemic immune response during the suckling period.

Neonatal leptin treatment reverses the bone-suppressive effects of maternal undernutrition in adult rat offspring

Alterations in the early life environment, including maternal undernutrition (UN) during pregnancy, can lead to increased risk of metabolic and cardiovascular disorders in offspring. Leptin treatment of neonates born to UN rats reverses the programmed metabolic phenotype, but the possible benefits of this treatment on bone tissue have not been defined. We describe for the first time the effects of neonatal leptin treatment on bone in adult offspring following maternal UN. Offspring from either UN or ad libitum-fed (AD) rats were treated with either saline or leptin (2.5 µg/ g.d on postnatal days (D)3–13) and were fed either a chow or high fat (HF) diet from weaning until study completion at D170. Analysis of micro-tomographic data of the left femur showed highly significant effects of UN on cortical and trabecular bone tissue indices, contributing to inferior microstructure and bone strength, almost all of which were reversed by early leptin life treatment. The HF fat diet negatively affected trabecular bone tissue, but the effects of only trabecular separation and number were reversed by leptin treatment. The negative effects of maternal UN on skeletal health in adult offspring might be prevented or attenuated by various interventions including leptin. Establishment of a minimal efficacious leptin dose warrants further study.

Appetite-regulating hormones in early life and relationships with type of feeding and body composition in healthy term infants

Introduction

Body composition in early life influences development of obesity during childhood and beyond. Appetite-regulating hormones (ARH) play a role in regulation of food intake and might thus influence body composition in later life. Studies on associations between ARH and body composition in early life are limited.

Methods

In 197 healthy term infants, we measured serum fasting levels of ghrelin, leptin, insulin, glucose-dependent insulinotropic peptide (GIP), pancreatic polypeptide (PP) and peptide YY (PYY) at 3 months and in 41 infants also at 6 months and their associations with type of feeding and longitudinal fat mass percentage (FM%) measured by air displacement plethysmography at 1, 3 and 6 months and abdominal visceral and subcutaneous fat, measured by ultrasound, at 3 and 6 months.

Results

Infants with formula feeding for 3 months had significantly higher serum levels of ghrelin, leptin, insulin, GIP and PP (p = 0.026, p = 0.018, p = 0.002, p < 0.001, resp.) and lower serum levels of PYY (p = 0.002) at 3 months than breastfed infants. Leptin and ghrelin correlated positively with FM% at 3 months and insulin with change in FM% between 1 and 3 months (r = 0.40, p < 0.001, r = 0.23, p < 0.05, r = 0.22, p < 0.01, resp.). Leptin at 3 months correlated with subcutaneous fat at 3 months (r = 0.23, p < 0.001), but not with visceral fat. Other ARH did not correlate with body composition.

Conclusion

Formula-fed infants had a different profile of ARH than breastfed infants, suggesting that lower levels of ghrelin, leptin and insulin in breastfed infants contribute to the protective role of breastfeeding against obesity development. Leptin, ghrelin and insulin were associated with fat mass percentage or its changes.

Maternal health and eating habits: metabolic consequences and impact on child health

Apart from direct inheritance and the effects of a shared environment, maternal health, eating habits and diet can affect offspring health by developmental programming. Suboptimal maternal nutrition (i.e., either a reduction or an increase above requirement) or other insults experienced by the developing fetus can induce significant changes in adipose tissue and brain development, energy homeostasis, and the structure of vital organs. These can produce long-lasting adaptations that influence later energy balance, and increase the susceptibility of that individual to obesity and the components of the metabolic syndrome. Studies that elucidate the mechanisms behind these associations will have a positive impact on the health of the future adult population and may help to contain the obesity epidemic.

Long Term Hippocampal and Cortical Changes Induced by Maternal Deprivation and Neonatal Leptin Treatment in Male and Female Rats

Maternal deprivation (MD) during neonatal life has diverse long-term behavioral effects and alters the development of the hippocampus and frontal cortex, with several of these effects being sexually dimorphic. MD animals show a marked reduction in their circulating leptin levels, not only during the MD period, but also several days later (PND 13). A neonatal leptin surge occurs in rodents (beginning around PND 5 and peaking between PND 9 and 10) that has an important neurotrophic role. We hypothesized that the deficient neonatal leptin signaling of MD rats could be involved in the altered development of their hippocampus and frontal cortex. Accordingly, a neonatal leptin treatment in MD rats would at least in part counteract their neurobehavioural alterations. MD was carried out in Wistar rats for 24 h on PND 9. Male and female MD and control rats were treated from PND 9 to 13 with rat leptin (3 mg/kg/day sc) or vehicle. In adulthood, the animals were submitted to the open field, novel object memory test and the elevated plus maze test of anxiety. Neuronal and glial population markers, components of the glutamatergic and cannabinoid systems and diverse synaptic plasticity markers were evaluated by PCR and/or western blotting. Main results include: 1) In some of the parameters analyzed, neonatal leptin treatment reversed the effects of MD (eg., mRNA expression of hippocampal IGF1 and protein expression of GFAP and vimentin) partially confirming our hypothesis; 2) The neonatal leptin treatment, per se, exerted a number of behavioral (increased anxiety) and neural effects (eg., expression of the following proteins: NG2, NeuN, PSD95, NCAM, synaptophysin). Most of these effects were sex dependent. An adequate neonatal leptin level (avoiding excess and deficiency) appears to be necessary for its correct neuro-programing effect.

Nutritional ingredients modulate adipokine secretion and inflammation in human primary adipocytes

Nutritional factors such as casein hydrolysates and long chain polyunsaturated fatty acids have been proposed to exert beneficial metabolic effects. We aimed to investigate how a casein hydrolysate (eCH) and long chain polyunsaturated fatty acids could affect human primary adipocyte function in vitro. Incubation conditions with the different nutritional factors were validated by assessing cell vitality with lactate dehydrogenase (LDH) release and neutral red incorporation. Intracellular triglyceride content was assessed with Oil Red O staining. The effect of eCH, a non-peptidic amino acid mixture (AA), and long-chain polyunsaturated fatty acids (LC-PUFAs) on adiponectin and leptin secretion was determined by enzyme-linked immunosorbent assay (ELISA). Intracellular adiponectin expression and nuclear factor-κB (NF-κB) activation were analyzed by Western blot, while monocyte chemoattractant protein-1 (MCP-1) release was explored by ELISA. The eCH concentration dependently increased adiponectin secretion in human primary adipocytes through its intrinsic peptide bioactivity, since the non-peptidic mixture, AA, could not mimic eCH’s effects on adiponectin secretion. Eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and DHA combined with arachidonic acid (ARA) upregulated adiponectin secretion. However, only DHA and DHA/ARA exerted a potentanti-inflammatory effect reflected by prevention of tumor necrosis factor-α (TNF-α) induced NF-κB activation and MCP-1 secretion in human adipocytes. eCH and DHA alone or in combination with ARA, may hold the key for nutritional programming through their anti-inflammatory action to prevent diseases with low-grade chronic inflammation such as obesity or diabetes.

Components of the metabolic syndrome in early childhood in very-low-birth-weight infants

BACKGROUND/AIMS

Term small-for-gestational-age and preterm born infants have an increased prevalence of metabolic syndrome components already in childhood. Data in very-low-birth-weight (VLBW) children are limited. We investigated the prevalence of metabolic syndrome components in VLBW infants at 2 years of corrected age.

METHODS

We included 38 children, participating in the Neonatal Insulin Replacement Therapy in Europe (NIRTURE) trial, a randomized controlled trial of early insulin therapy in VLBW infants. Metabolic syndrome components were defined as: body mass index SDS >2; blood pressure (systolic and/or diastolic) ≥ 90th percentile; triglycerides ≥ 0.98 mmol/l; high-density lipoprotein (HDL) cholesterol ≤ 1.03 mmol/l; glucose ≥ 5.6 mmol/l.

RESULTS

Two children (5%) had three metabolic syndrome components, 13 children (34%) had two components, and 11 children (29%) one component. 63% had raised blood pressure (prevalence higher in boys), 32% low HDL, and 30% high triglycerides (prevalence lower in early insulin group). In children with body mass index SDS <0, insulin-treated children had higher HDL than children with standard care. Systolic blood pressure was correlated with growth between term and 2 years of corrected age.

CONCLUSIONS

VLBW infants already have a high prevalence of metabolic syndrome components at 2 years of corrected age. Early insulin treatment could have long-term benefits for some of these components.

Early-life adversity programs emotional functions and the neuroendocrine stress system: the contribution of nutrition, metabolic hormones and epigenetic mechanisms

Clinical and pre-clinical studies have shown that early-life adversities, such as abuse or neglect, can increase the vulnerability to develop psychopathologies and cognitive decline later in life. Remarkably, the lasting consequences of stress during this sensitive period on the hypothalamic-pituitary-adrenal axis and emotional function closely resemble the long-term effects of early malnutrition and suggest a possible common pathway mediating these effects. During early-life, brain development is affected by both exogenous factors, like nutrition and maternal care as well as by endogenous modulators including stress hormones. These elements, while mostly considered for their independent actions, clearly do not act alone but rather in a synergistic manner. In order to better understand how the programming by early-life stress takes place, it is important to gain further insight into the exact interplay of these key elements, the possible common pathways as well as the underlying molecular mechanisms that mediate their effects. We here review evidence that exposure to both early-life stress and early-life under-/malnutrition similarly lead to life-long alterations on the neuroendocrine stress system and modify emotional functions. We further discuss how the different key elements of the early-life environment interact and affect one another and next suggest a possible role for the early-life adversity induced alterations in metabolic hormones and nutrient availability in shaping later stress responses and emotional function throughout life, possibly via epigenetic mechanisms. Such knowledge will help to develop intervention strategies, which gives the advantage of viewing the synergistic action of a more complete set of changes induced by early-life adversity.

Development of food intake controls: neuroendocrine and environmental regulation of food intake during early life

This article is part of a Special Issue "Energy Balance". The development of neuroendocrine regulation of food intake during early life has been shaped by natural selection to allow for optimal growth and development rates needed for survival. In vertebrates, neonates or early larval forms typically exhibit "feeding drive," characterized by a developmental delay in 1) responsiveness of the hypothalamus to satiety signals (e.g., leptin, melanocortins) and 2) sensitivity to environmental cues that suppress food intake. Homeostatic regulation of food intake develops once offspring transition to later life history stages when growth is slower, neuroendocrine systems are more mature, and appetite becomes more sensitive to environmental or social cues. Across vertebrate groups, there is a tremendous amount of developmental plasticity in both food intake regulation and stress responsiveness depending on the environmental conditions experienced during early life history stages or by pregnant/brooding mothers. This plasticity is mediated through the organizing effects of hormones acting on the food intake centers of the hypothalamus during development, which alter epigenetic expression of genes associated with ingestive behaviors. Research is still needed to reveal the mechanisms through which environmental conditions during development generate and maintain these epigenetic modifications within the lifespan or across generations. Furthermore, more research is needed to determine whether observed patterns of plasticity are adaptive or pathological. It is clear, however, that developmental programming of food intake has important effects on fitness, and therefore, has ecological and evolutionary implications.

Additive effects of maternal high fat diet during lactation on mouse offspring

Recent reports indicated that nutrition in early infancy might influence later child health outcomes such as obesity and metabolic syndrome. Therefore, we examined the effects of maternal high fat diet (HFD) during lactation on the onset of a metabolic syndrome in their offspring. All offspring were cross-fostered by dams on the same or opposite diet to yield 4 groups: offspring from HFD-fed dams suckled by HFD-fed dams (OHH) and by control diet (CD)-fed dams (OHC) and CD-fed dams suckled by HFD-fed dams (OCH) and by CD-fed dams (OCC) mice. We examined several metabolic syndrome-related factors including body weight, blood pressure, glucose tolerance and adipocytokines. Mean body weights of OHH and OCH mice were significantly higher than those of OHC and OCC mice, respectively, with elevated systolic blood pressure. Moreover, OHH and OCH mice revealed significantly worse glucose tolerance compared with the OHC and OCC mice, respectively. Triglyceride and leptin levels were significantly increased and adiponectin levels were significantly reduced by the maternal HFD during lactation, with similar changes in leptin and adiponectin mRNA expression but without histone modifications in adipose tissues. In addition, maternal obesity induced by HFD during lactation increased and prolonged the leptin surge in the offspring and the gender differences of leptin surge were observed. Our data suggested that maternal HFD during lactation might have an additive effect on the onset of the metabolic syndrome in the offspring, irrespective of the nutritional status in utero through the modified leptin surge.

The role of leptin in diencephalic syndrome

Diencephalic syndrome is a rare condition associated with central nervous system tumors. The most common presentation is secondary failure to thrive with proper caloric intake and no statural impairment. Despite the importance of this syndrome, little is known of its pathophysiology. Some reports have documented changes in human growth hormone and insulin levels at the onset, whereas others have described endocrine disorders of hypothalamic insufficiency resulting from surgery of the tumor. It has been suggested that the hormonal changes described, such as increased human growth hormone and ghrelin or decreased insulin and leptin levels, are related to a patient's BMI. These findings support the role of these 4 hormones as indicators of the patient's nutritional status but not as mediators or potential therapeutic targets of the disease. We report the case of an infant who initially presented with tumor progression and, after chemotherapy, progressive weight gain and reduced tumor size. Because he presented no hormonal deficiencies or obesity after therapy, we were able to analyze his hormonal status uninfluenced by effects of metabolic treatment or excess weight. Although ghrelin and leptin levels have been related to nutritional status, our patient's leptin levels fell when tumor size decreased and weight increased: an extraordinary finding because leptin concentration is expected to increase with weight gain. This paradoxical response suggests that leptin may be dysregulated in diencephalic syndrome or that the diencephalic astrocytoma may have had an effect on leptin secretion.

The role of leptin in the control of insulin-glucose axis

Obesity and diabetes mellitus are great public health concerns throughout the world because of their increasing incidence and prevalence. Leptin, the adipocyte hormone, is well known for its role in the regulation of food intake and energy expenditure. In addition to the regulation of appetite and satiety that recently has attracted much attentions, insight has also been gained into the critical role of leptin in the control of the insulin-glucose axis, peripheral glucose and insulin responsiveness. Since the discovery of leptin, leptin has been taken for its therapeutic potential to obesity and diabetes. Recently, the therapeutic effects of central leptin gene therapy have been reported in insulin-deficient diabetes in obesity animal models such as ob/ob mise, diet-induced obese mice, and insulin-deficient type 1 diabetes mice, and also in patients with inactivating mutations in the leptin gene. Herein, we review the role of leptin in regulating feeding behavior and glucose metabolism and also the therapeutic potential of leptin in obesity and diabetes mellitus.

The hypothalamus-adipose axis is a key target of developmental programming by maternal nutritional manipulation

Epidemiological studies initially demonstrated that maternal undernutrition leading to low birth weight may predispose for energy balance disorders throughout life. High birth weight due to maternal obesity or diabetes, inappropriate early post-natal nutrition and rapid catch-up growth may also sensitise to increased risk of obesity. As stated by the Developmental Origin of Health and Disease concept, the perinatal perturbation of foetus/neonate nutrient supply might be a crucial determinant of individual programming of body weight set point. The hypothalamus-adipose axis plays a pivotal role in the maintenance of energy homoeostasis controlling the nutritional status and energy storage level. The perinatal period largely corresponds to the period of brain maturation, neuronal differentiation and active adipogenesis in rodents. Numerous dams and/or foetus/neonate dietary manipulation models were developed to investigate the mechanisms underlying perinatal programming in rodents. These models showed several common offspring hypothalamic consequences such as impaired neurogenesis, neuronal functionality, nuclei structural organisation and feeding circuitry hardwiring. These alterations led to a persistent reprogrammed appetite system that favoured the orexigenic pathways, leptin/insulin resistance and hyperphagia. Impaired hypothalamic sympathetic outflow to adipose tissue and/or reduced innervation may also account for modified fat cell metabolism. Thus, enhanced adipogenesis and/or lipogenesis capacities may predispose the offspring to fat accumulation. Abnormal hypothalamus-adipose axis circadian rhythms were also evidenced. This review mainly focuses on studies in rodents. It highlights hormonal and epigenetic mechanisms responsible for long-lasting programming of energy balance in the offspring. Dietary supplementation may provide a therapeutic option using a specific regimen for reversing adverse programming outcomes in humans.

Effects of coronary ischemia-reperfusion in a rat model of early overnutrition. Role of angiotensin receptors

Background

Obesity during childhood has dramatically increased worldwide in the last decades. Environmental factors acting early in life, including nutrition, play an important role in the pathogenesis of obesity and cardiovascular diseases in adulthood.

Aims

To analyze the effects of early overfeeding on the heart and coronary circulation, the effect of ischemia-reperfusion (I/R) and the role of the renin-angiotensin system (RAS) were studied in isolated hearts from control and overfed rats during lactation.

Methods and Results

On the day of birth litters were adjusted to twelve pups per mother (control) or to three pups per mother (overfed). At weaning (21 days) the rats were killed and the heart perfused in a Langendorff system and subjected to 30 min of ischemia followed by 15 min of reperfusion. The contractility (left developed intraventricular pressure) was lower in the hearts from overfed rats, and was reduced by I/R in hearts from control but not from overfed rats. I/R also reduced the coronary vasoconstriction to angiotensin II more in hearts from control than from overfed rats, and the vasodilatation to bradykinin similarly in both experimental groups. The expression of both angiotensin AGTRa and AGTR2 receptors was increased in the myocardium of overfed rats, and I/R increased the expression of both receptors in control rats but reduced it in overfed rats. The expression of apoptotic and antiapoptotic markers was increased in hearts of overfed rats compared with control, and further increased by I/R.

Conclusions

These results suggest that both overfeeding and I/R impair cardiac and coronary function due, at least in part, to activation of the angiotensin pathway. However, overfeeding may reduce the impairment of ventricular contractility by I/R.

Neurodevelopmental consequences of maternal distress: what do we really know?

A simple internet search of 'maternal stress and pregnancy' turns up hundreds of hits explaining that an adverse intrauterine environment can affect fetal development and potentially lead to various learning, behavioral, and mood disorders in childhood, as well as complex diseases such as obesity and cardiovascular conditions later in life. Indeed, a growing body of literature now links several intrauterine challenges, including maternal obesity and stress, with adverse developmental outcomes in the child. Over the past 5 years, nearly 5000 publications have explored the consequences of maternal distress on young offspring, a marked increase from the 475 published studies over a comparable period 20 years ago. Yet, despite this explosion of research and widespread warnings to pregnant mothers, we still lack a basic understanding of the pathophysiology linking adverse maternal health to the onset of disease in the child, especially regarding how prenatal and perinatal challenges might affect brain development. Recent studies have begun to explore the cellular basis of the abnormal brain cytoarchitecture associated with fetal exposure to intrauterine challenges. Here, our goal is to review the scientific evidence that maternal distress interferes with key neurodevelopmental steps, as an entry point toward mapping the pathophysiology of pre- and perinatal stress on the unborn child's brain.

Correlation between Helicobacter pylori infection and hemoglobin A1c expression

Helicobacter pylori (H. pylori) is a gram-negative bacterium that is closely related with the pathogenesis of chronic gastritis, peptic ulcer, gastric carcinoma as well as many extra-gastrointestinal tract diseases such as coronary heart disease, iron deficiency anemia, idiopathic thrombocytopenic purpura, and diabetes mellitus (DM). Hemoglobin A1c (HbA1c) level is useful in diagnosing and monitoring DM. Recent studies showed that H. pylori is involved in the up-regulation of HbA1c level in DM patients through modulating the expression of leptin and ghrelin, whose interactions affect obesity, insulin sensitivity, glucose homeostasis and DM. Further studies on the association between H. pylori infection and HbA1c will certainly provide new prospects for early diagnosis and treatment of H. pylori-related DM and its complications.