Neonatal nutrition: metabolic programming of pancreatic islets and obesity

Can breastfeeding affect the rest of our life?

The breastfeeding period is one of the most important critical windows in our development, since milk, our first food after birth, contains several compounds, such as macronutrients, micronutrients, antibodies, growth factors and hormones that benefit human health. Indeed, nutritional, and environmental alterations during lactation, change the composition of breast milk and induce alterations in the child's development, such as obesity, leading to the metabolic dysfunctions, cardiovascular diseases and neurobehavioral disorders. This review is based on experimental animal models, most of them in rodents, and summarizes the impact of an adequate breast milk supply in view of the developmental origins of health and disease (DOHaD) concept, which has been proposed by researchers in the areas of epidemiology and basic science from around the world. Here, experimental advances in understanding the programming during breastfeeding were compiled with the purpose of generating knowledge about the genesis of chronic noncommunicable diseases and to guide the development of public policies to deal with and prevent the problems arising from this phenomenon. This review article is part of the special issue on "Cross talk between periphery and brain".

Effect of Postnatal Nutritional Environment Due to Maternal Diabetes on Beta Cell Mass Programming and Glucose Intolerance Risk in Male and Female Offspring

Besides the fetal period, the suckling period is a critical time window in determining long-term metabolic health. We undertook the present study to elucidate the impact of a diabetic suckling environment alone or associated with an in utero diabetic environment on beta cell mass development and the risk of diabetes in the offspring in the long term. To that end, we have compared two experimental settings. In setting 1, we used Wistar (W) rat newborns resulting from W ovocytes (oW) transferred into diabetic GK rat mothers (pGK). These oW/pGK neonates were then suckled by diabetic GK foster mothers (oW/pGK/sGK model) and compared to oW/pW neonates suckled by normal W foster mothers (oW/pW/sW model). In setting 2, normal W rat newborns were suckled by diabetic GK rat foster mothers (nW/sGK model) or normal W foster mothers (nW/sW model). Our data revealed that the extent of metabolic disorders in term of glucose intolerance and beta cell mass are similar between rats which have been exposed to maternal diabetes both pre- and postnatally (oW/pGK/sGK model) and those which have been exposed only during postnatal life (nW/sW model). In other words, being nurtured by diabetic GK mothers from birth to weaning was sufficient to significantly alter the beta cell mass, glucose-induced insulin secretion and glucose homeostasis of offspring. No synergistic deleterious effects of pre-and postnatal exposure was observed in our setting.

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.

The Japanese Wagyu beef industry: current situation and future prospects - A review

In Japan, Wagyu cattle include four Japanese breeds; Black, Brown, Shorthorn, and Polled. Today, the renowned brand name Wagyu includes not only cattle produced in Japan, but also cattle produced in countries such as Australia and the United States. In recent years, the intramuscular fat percentage in beef (longissimus muscle) from Japanese Black cattle has increased to be greater than 30%. The Japanese Black breed is genetically predisposed to producing carcass lipids containing higher concentrations of monounsaturated fatty acids than other breeds. However, there are numerous problems with the management of this breed including high production costs, disposal of untreated excrement, the requirement for imported feed, and food security risks resulting from various viral diseases introduced by imported feed. The feeding system needs to shift to one that is more efficient, and improves management for farmers, food security for consumers, and the health environment for residents of Japan. Currently, we are developing a metabolic programming and an information and communications technology (ICT, or Interne of Things) management system for Wagyu beef production as future systems. If successful, we will produce safe, high-quality Wagyu beef using domestic pasture resources while solving the problems of how to utilize increasing areas of abandoned agricultural land and to make use of the plant-based feed resources in Japan’s mountainous areas.

Epigenetic Programming of Synthesis, Release, and/or Receptor Expression of Common Mediators Participating in the Risk/Resilience for Comorbid Stress-Related Disorders and Coronary Artery Disease

Corticotrophin releasing factor, vasopressin, oxytocin, natriuretic hormones, angiotensin, neuregulins, some purinergic substances, and some cytokines contribute to the long-term modulation and restructuring of cardiovascular regulation networks and, at the same time, have relevance in situations of comorbid abnormal stress responses. The synthesis, release, and receptor expression of these mediators seem to be under epigenetic control since early stages of life, possibly underlying the comorbidity to coronary artery disease (CAD) and stress-related disorders (SRD). The exposure to environmental conditions, such as stress, during critical periods in early life may cause epigenetic programming modifying the development of pathways that lead to stable and long-lasting alterations in the functioning of these mediators during adulthood, determining the risk of or resilience to CAD and SRD. However, in contrast to genetic information, epigenetic marks may be dynamically altered throughout the lifespan. Therefore, epigenetics may be reprogrammed if the individual accepts the challenge to undertake changes in their lifestyle. Alternatively, epigenetics may remain fixed and/or even be inherited in the next generation. In this paper, we analyze some of the common neuroendocrine functions of these mediators in CAD and SRD and summarize the evidence indicating that they are under early programming to put forward the theoretical hypothesis that the comorbidity of these diseases might be epigenetically programmed and modified over the lifespan of the individual.

Effects of infant formula composition on long-term metabolic health

Early nutrition may have long-lasting metabolic impacts in adulthood. Even though breast milk is the gold standard, most infants are at least partly formula-fed. Despite obvious improvements, infant formulas remain perfectible to reduce the gap between breastfed and formula-fed infants. Improvements such as reducing the protein content, modulating the lipid matrix and adding prebiotics, probiotics and synbiotics, are discussed regarding metabolic health. Numerous questions remain to be answered on how impacting the infant formula composition may modulate the host metabolism and exert long-term benefits. Interactions between early nutrition (composition of human milk and infant formula) and the gut microbiota profile, as well as mechanisms connecting gut microbiota to metabolic health, are highlighted. Gut microbiota stands as a key actor in the nutritional programming but additional well-designed longitudinal human studies are needed.

Impact of perinatal exposure to sucrose or high fructose corn syrup (HFCS-55) on adiposity and hepatic lipid composition in rat offspring

KEY POINTS

Fructose-containing sugars, including sucrose and high fructose corn syrup (HFCS), have been implicated in the epidemics of obesity and type 2 diabetes. Few studies have evaluated the impact of perinatal exposure to these sugars on metabolic and physiological outcomes in the offspring. Using a rat model, offspring exposed to a maternal sucrose or HFCS diet during the prenatal and/or suckling periods were found to have altered adiposity and liver fat content and composition at weaning. Plasma levels of free fatty acids remained elevated in young adulthood, but consumption of a control diet following weaning appeared to ameliorate most other effects of perinatal exposure to a maternal high-sugar diet. Guidelines for maternal nutrition should advise limiting consumption of fructose-containing sugars, and it is particularly important that these recommendations include maternal nutrition during lactation.

ABSTRACT

Perinatal exposure to excess maternal intake of added sugars, including fructose and sucrose, is associated with an increased risk of obesity and type 2 diabetes in adult life. However, it is unknown to what extent the type of sugar and the timing of exposure affect these outcomes. The aim of this study was to determine the impact of exposure to maternal consumption of a 10% (w/v) beverage containing sucrose or high fructose corn syrup-55 (HFCS-55) during the prenatal and/or suckling periods on offspring at 3 and 12 weeks, utilising a cross-fostering approach in a rodent model. Perinatal sucrose exposure decreased plasma glucose concentrations in offspring at 3 weeks, but did not alter glucose tolerance. Increased adiposity was observed in 3-week-old offspring exposed to sucrose or HFCS-55 during suckling, with increased hepatic fat content in HFCS-55-exposed offspring. In terms of specific fatty acids, hepatic monounsaturated (omega-7 and -9) fatty acid content was elevated at weaning, and was most pronounced in sucrose offspring exposed during both the prenatal and suckling periods, and HFCS-55 offspring exposed during suckling only. By 12 weeks, the effects on adiposity and hepatic lipid composition were largely normalised. However, exposure to either sucrose or HFCS-55 during the prenatal period only was associated with elevated plasma free fatty acids at weaning, and this effect persisted until 12 weeks. This study suggests that the type of sugar and the timing of exposure (prenatal or suckling periods) are both important for determining the impact on metabolic health outcomes in the offspring.

Brief neonatal nutritional supplementation has sex-specific effects on glucose tolerance and insulin regulating genes in juvenile lambs

BACKGROUND

The nutritional plane and composition during fetal life can impact upon growth and epigenetic regulation of genes affecting pancreatic β-cell development and function. However, it is not clear whether β-cell development can be altered by nutritional factors or growth rate after birth. We therefore investigated the effect of neonatal nutritional supplements on growth, glucose tolerance, and pancreatic development in lambs.

METHODS

Newborn lambs were randomized to daily nutritional supplements, calculated to increase macronutrient intake to a similar degree as human breast milk fortifier, or an equivalent volume of water, for 2 wk while continuing to suckle ewe milk. Intravenous glucose tolerance test (IVGTT) was performed at 4 mo of age, and pancreata collected for molecular analysis.

RESULTS

Supplemented lambs had slower weight gain than controls. In supplemented lambs, insulin response to IVGTT was increased in males but decreased in females, compared to same sex controls, and was unrelated to growth rate. mRNA expression of key genes in β-cell development showed sexually dimorphic effects. Epigenetic change occurred in the promotor region of PDX1 gene with decreased suppression and increased activation marks in supplemented lambs of both sexes.

CONCLUSION

Nutritional interventions in early life have long-term, sex-specific effects on pancreatic function.

Postnatal β-cell maturation is associated with islet-specific microRNA changes induced by nutrient shifts at weaning

Glucose-induced insulin secretion is an essential function of pancreatic β-cells that is partially lost in individuals affected by Type 2 diabetes. This unique property of β-cells is acquired through a poorly understood postnatal maturation process involving major modifications in gene expression programs. Here we show that β-cell maturation is associated with changes in microRNA expression induced by the nutritional transition that occurs at weaning. When mimicked in newborn islet cells, modifications in the level of specific microRNAs result in a switch in the expression of metabolic enzymes and cause the acquisition of glucose-induced insulin release. Our data suggest microRNAs have a central role in postnatal β-cell maturation and in the determination of adult functional β-cell mass. A better understanding of the events governing β-cell maturation may help understand why some individuals are predisposed to developing diabetes and could lead to new strategies for the treatment of this common metabolic disease.

Pancreatic β-cells are less responsive to changes in glucose concentration in newborn than in adult rats. Here, the authors show that functional β-cell maturation is associated with changes in miRNA expression induced by nutritional shifts at the suckling-to-weaning transition.

Potential of the application of epigenetics in animal production

Our many current environmental challenges, including worldwide abnormal weather, global warming, and pollution, necessitate a new and innovative strategy for animal production for the next generation. This strategy should incorporate not only higher-efficiency production, but also advanced biological concepts and multi-functional agricultural techniques, into environmentally friendly systems. Recent research has discovered a unique phenomenon referred to as ‘foetal and neonatal programming’, which is based on ‘the developmental origins of health and disease (DOHaD)’ concept. These studies have shown that alterations in foetal and early postnatal nutrition and endocrine status may result in developmental adaptations that permanently change the structure, physiology and metabolism of affected animals during adult life. Ruminants fill an important ecological niche that capitalises on the symbiotic relationship between fibre-fermenting ruminal microbes and the mammalian demand for usable nutrients. The timing of the perturbation in maternal nutrient availability plays an important role in determining the effect that the foetal and neonatal programming will have on the developing placenta or foetus and offspring performance. Developmental programming through nutritional manipulations may help the ruminant, as an effective grass–protein converter, fulfil its production potential.

Infant formula supplemented with low protein and high carbohydrate alters the intestinal microbiota in neonatal SD rats

Background

Infant microbiota is influenced by numerous factors, such as delivery mode, environment, prematurity and diet (breast milk or formula) and last but not least, the diet composition. In the diet composition, protein and carbohydrate are very important for the growth of microbiota, many infant fomulas (different ratio protein/carbohydrate) can regulate the development of gut microbiota by different metabolism. The effect of low-protein, high-carbohydrate infant formula on the establishment of microbiota remains unclear, and the effect of human breast milk on the gut microbiota of the rats has also not been reported.

Results

In a 7 d intervention, a total of 36 neonatal SD rats (14 d old) were randomly assigned to the following groups: (1) breast-fed group (A group); (2) low-protein, high-carbohydrate infant formula-fed group (B group); (3) human breast milk-fed group (C group). After 7 days, we selected 6 rats at random from each group to study. Microbial composition in the contents of the large intestines was analysed by Miseq Sequencing. Significantly different (p<0.05) microbial colonisation patterns were observed in the large intestines of breast-fed group from low-protein, high-carbohydrate infant formula-fed and human breast milk-fed rats, but the microbiota of low-protein, high-carbohydrate infant formula-fed group and human breast milk-fed group have high similarity. At the phylum level, the absolute quantity of Bacteroidetes, Firmicutes and Proteobacteria (p<0.001) significantly differentiated in breast-fed group from low- protein, high- carbohydrate infant formula-fed and human breast milk-fed groups. Lachnospiraceae, Bacteroidaceae, Porphyromonadaceae and Prevotellaceae were the 4 top families in breast-fed group, but the top 4 families in low-protein, high- carbohydrate infant formula-fed and human breast milk-fed groups were the same, which were Bacteroidaceae, Enterobacteriaceae, Porphyromonadaceae and Lachnospiraceae. At the genus level, Bacteroides was the most abundant division, their OTUS abundance in three groups was 14.91%, 35.94%, 43.24% respectively.

Conclusions

This study showed that infant formula closer resembling human milk was more different than rats’ breast milk and led to a microbiota profile similar to that for human breast milk-fed neonates. The finding could support a new thinking to develop infant formulas, and provide much more details than what is known previously.

Electronic supplementary material

The online version of this article (doi:10.1186/s12866-014-0279-2) contains supplementary material, which is available to authorized users.

Prematurity and programming: contribution of neonatal Intensive Care Unit interventions

Contemporary clinical practice for the care of the prematurely born babies has markedly improved their rates of survival so that most of these babies are expected to grow up to live a healthy functional life. Since the clinical follow-up is of short duration (years), only limited data are available to relate non-communicable diseases in adult life to events and interventions in the neonatal period. The major events that could have a programming effect include: (1) intrauterine growth restriction; (2) interruption of pregnancy with change in redox and reactive oxygen species (ROS) injury; (3) nutritional and pharmacological protocols for clinical care; and (4) nutritional care in the first 2 years resulting in accelerated weight gain. The available data are discussed in the context of perturbations in one carbon (methyl transfer) metabolism and its possible programming effects. Although direct evidence for genomic methylation is not available, clinical and experimental data on impact of redox and ROS, of low protein intake, excess methionine load and vitamin A, on methyl transfers are reviewed. The consequences of antenatal and postnatal administration of glucocorticoids are presented. Analysis of the correlates of insulin sensitivity at older age, suggests that premature birth is the major contributor, and is compounded by gain in weight during infancy. We speculate that premature interruption of pregnancy and neonatal interventions by affecting one carbon metabolism may cause programming effects on the immature baby. These can be additive to the effects of intrauterine environment (growth restriction) and are compounded by accelerated growth in early infancy.

Breast milk banking: current opinion and practice in Australian neonatal intensive care units

AIM

To find out the knowledge and attitudes of health-care professionals (HCPs) in Australian neonatal intensive care units (NICUs) towards breast milk banking (BMBg) and pasteurised donated breast milk (PDBM).

METHODS

Cross-sectional structured survey of HCPs in all 25 NICUs in Australia.

RESULTS

Response rate was 43.4% (n= 358 of 825). Participants included nurses and midwives (291, 81.3%) and the remainder were neonatologists and neonatal trainees (67, 18.7%). A variable number of HCPs agreed that PDBM would decrease the risk of necrotising enterocolitis (81%) and allergies (48.9%), 8.4% thought PDBM will carry risk of infections and 78.8% agreed that PDBM is preferable over formula, but only 67.5% thought that establishing breast milk banks (BMBs) are justifiable. Significant differences were found between doctors and nurses/midwives, with 19.4% of doctors compared with 5.8% of nurses/midwives agreed that PDBM carried an increased risk of infection. Although, over 90% of nurses/midwives and 70% of doctors agreed that the donation of breast milk is important, only 71% of nurses/midwives and 52.2% of doctors thought that setting up a BMB was justifiable.

CONCLUSION

The opinions about BMBg differ widely between HCPs; however, the majority support the practice. HCPs had different knowledge gaps in regard to BMBg. Nurses/midwives positively view the practice of BMBg more strongly compared with neonatologists.

Long term metabolic impact of high protein neonatal feeding: a preliminary study in male rat pups born with a low birth weight

BACKGROUND & AIMS

Nutrition received in early life may impact adult health. The aim of the study was to determine whether high protein feeding in neonatal period would have long term metabolic effects in an animal model of low birth weight infants.

METHODS

Male rat pups born from dams receiving a low protein diet during gestation were separated from their mothers, and equipped with gastrostomy tubes to receive as their sole feeding a milk formula of either adequate protein (AP; n = 14; 8.7 g protein/dL; total energy: 155 kcal/100 g), or high protein content (HP; n = 14; 13.0 g protein/dL; total energy: 171 kcal/100 g) between the 7th (D7) and 21st day (D21) of life. Rats were then weaned to standard chow until sacrificed at adulthood.

RESULTS

At D18, HP feeding was associated with higher estimated rates of protein turnover (p = 0.007) and synthesis (p = 0.051), as assessed using l-[U-(13)C]valine infusion. HP milk feeding in early life was associated with an increase in weight gain from puberty through adulthood, along with an increase in food intake, serum insulin (179 ± 58 vs. 55 ± 7 pmol/L; means ± SE), pancreatic β-cell number, plasma triglycerides (95 ± 8 vs. 73 ± 9 mg/dL), serum leptin (9.7 ± 1.0 vs. 5.5 ± 1.2 ng/mL), mesenteric fat mass, and adipocyte size.

CONCLUSIONS

In an animal model of low birth weight infants, high protein neonatal feeding may have a lasting effect on fat and glucose metabolism, potentially leading to "metabolic syndrome" in adulthood.

Child health, developmental plasticity, and epigenetic programming

Plasticity in developmental programming has evolved in order to provide the best chances of survival and reproductive success to the organism under changing environments. Environmental conditions that are experienced in early life can profoundly influence human biology and long-term health. Developmental origins of health and disease and life-history transitions are purported to use placental, nutritional, and endocrine cues for setting long-term biological, mental, and behavioral strategies in response to local ecological and/or social conditions. The window of developmental plasticity extends from preconception to early childhood and involves epigenetic responses to environmental changes, which exert their effects during life-history phase transitions. These epigenetic responses influence development, cell- and tissue-specific gene expression, and sexual dimorphism, and, in exceptional cases, could be transmitted transgenerationally. Translational epigenetic research in child health is a reiterative process that ranges from research in the basic sciences, preclinical research, and pediatric clinical research. Identifying the epigenetic consequences of fetal programming creates potential applications in clinical practice: the development of epigenetic biomarkers for early diagnosis of disease, the ability to identify susceptible individuals at risk for adult diseases, and the development of novel preventive and curative measures that are based on diet and/or novel epigenetic drugs.

Does consumption of processed foods explain disparities in the body weight of individuals? The case of Guatemala

Overweight/obesity, caused by the 'nutrition transition', is identified as one of the leading risk factors for non-communicable mortality. The nutrition transition in developing countries is associated with a major shift from the consumption of staple crops and whole grains to highly and partially processed foods. This study examines the contribution of processed foods consumption to the prevalence of overweight/obesity in Guatemala using generalized methods of moments (GMM) regression. The results show that all other things remaining constant, a 10% point increase in the share of partially processed foods from the total household food expenditure increases the BMI of family members (aged 10 years and above) by 3.95%. The impact of highly processed foods is much stronger. A 10% point increase in the share of highly processed food items increases the BMI of individuals by 4.25%, ceteris paribus. The results are robust when body weight is measured by overweight/obesity indicators. These findings suggest that increasing shares of partially and highly processed foods from the total consumption expenditure could be one of the major risk factors for the high prevalence of overweight/obesity in the country.

Hypothalamus integrity and appetite regulation in low birth weight rats reared artificially on a high-protein milk formula

High-protein (HP) milk formulas are routinely used in infants born with a low birth weight (LBW) to enhance growth and ensure a better verbal IQ development. Indirect evidence points to a link between an HP intake during early life and the prevalence of obesity in later life. We hypothesized that HP milk supplementation to LBW pups during early postnatal life would impact hypothalamic appetite neuronal pathways development with consequences, at adulthood, on energy homeostasis regulation. Rat pups born with a LBW were equipped with gastrostomy tubes on the fifth day of life. They received a milk formula with either normal protein (NP, 8.7 g protein/dl) or high protein content (HP; 13.0 g protein/dl) and were subsequently weaned to a standard, solid diet at postnatal day 21. Rats that had been fed HP content milk gained more weight at adulthood associated with an increase of plasma insulin, leptin and triglycerides concentrations compared to NP rats. Screening performed on hypothalamus in development from the two groups of rats identified higher gene expression for cell proliferation and neurotrophin markers in HP rats. Despite these molecular differences, appetite neuronal projections emanating from the arcuate nucleus did not differ between the groups. Concerning feeding behavior at adulthood, rats that had been fed HP or NP milk exhibited differences in the satiety period, resting postprandial duration and nocturnal meal pattern. The consequences of HP milk supplementation after LBW will be discussed in regard to neural development and metabolic anomalies.

Timing and Duration of Drug Exposure Affects Outcomes of a Drug-Nutrient Interaction During Ontogeny

Significant drug-nutrient interactions are possible when drugs and nutrients share the same absorption and disposition mechanisms. During postnatal development, the outcomes of drug-nutrient interactions may change with postnatal age since these processes undergo ontogenesis through the postnatal period. Our study investigated the dependence of a significant drug-nutrient interaction (cefepime-carnitine) on the timing and duration of drug exposure relative to postnatal age. Rat pups were administered cefepime (5 mg/kg) twice daily subcutaneously according to different dosing schedules (postnatal day 1-4, 1-8, 8-11, 8-20, or 1-20). Cefepime significantly reduced serum and heart L-carnitine levels in postnatal day 1-4, 1-8 and 8-11 groups and caused severe degenerative changes in ventricular myocardium in these groups. Cefepime also altered the ontogeny of several key L-carnitine homeostasis pathways. The qualitative and quantitative changes in levels of hepatic γ-butyrobetaine hydroxylase mRNA and activity, hepatic trimethyllysine hydroxlase mRNA, intestinal organic cation/carnitine transporter (Octn) mRNA, and renal Octn2 mRNA depended on when during postnatal development the cefepime exposure occurred and duration of exposure. Despite lower levels of heart L-carnitine in earlier postnatal groups, levels of carnitine palmitoyltransferase mRNA and activity, heart Octn2 mRNA and ATP levels in all treatment groups remained unchanged with cefepime exposure. However, changes in other high energy phosphate substrates were noted and reductions in the phosphocreatine/ATP ratio were found in rat pups with normal serum L-carnitine levels. In summary, our data suggest a significant drug-nutrient transport interaction in developing neonates, the nature of which depends on the timing and duration of exposure relative to postnatal age.

The early nutritional environment of mice determines the capacity for adipose tissue expansion by modulating genes of caveolae structure

While the phenomenon linking the early nutritional environment to disease susceptibility exists in many mammalian species, the underlying mechanisms are unknown. We hypothesized that nutritional programming is a variable quantitative state of gene expression, fixed by the state of energy balance in the neonate, that waxes and wanes in the adult animal in response to changes in energy balance. We tested this hypothesis with an experiment, based upon global gene expression, to identify networks of genes in which expression patterns in inguinal fat of mice have been altered by the nutritional environment during early post-natal development. The effects of over- and under-nutrition on adiposity and gene expression phenotypes were assessed at 5, 10, 21 days of age and in adult C57Bl/6J mice fed chow followed by high fat diet for 8 weeks. Under-nutrition severely suppressed plasma insulin and leptin during lactation and diet-induced obesity in adult mice, whereas over-nourished mice were phenotypically indistinguishable from those on a control diet. Food intake was not affected by under- or over-nutrition. Microarray gene expression data revealed a major class of genes encoding proteins of the caveolae and cytoskeleton, including Cav1, Cav2, Ptrf (Cavin1), Ldlr, Vldlr and Mest, that were highly associated with adipose tissue expansion in 10 day-old mice during the dynamic phase of inguinal fat development and in adult animals exposed to an obesogenic environment. In conclusion gene expression profiles, fat mass and adipocyte size in 10 day old mice predicted similar phenotypes in adult mice with variable diet-induced obesity. These results are supported by phenotypes of KO mice and suggest that when an animal enters a state of positive energy balance adipose tissue expansion is initiated by coordinate changes in mRNA levels for proteins required for modulating the structure of the caveolae to maximize the capacity of the adipocyte for lipid storage.

Aortic vasoreactivity during a postnatal critical window of the pancreas in rats

Changes in aortic vasoreactivity during the postnatal pancreatic critical window, where insulin and glucose, which modify vasoreactivity, are elevated, were studied and compared to those in control and metabolic syndrome (MS) rats. Twelve 21- and 28-day-old rats were used. To develop MS rats, male Wistar animals were given 30% sucrose in drinking water since weaning and used when 6 months old. Glucose and insulin levels were higher during suckling and decreased after weaning, and insulin and triglycerides levels increased in MS rats. Contraction elicited by norepinephrine (NE) was stronger than KCl contraction at all ages. KCl-induced contraction increased with, age being stronger in control rats; it further increased in MS rats. Norepinephrine-induced contraction increased from day 12 to day 28 but stabilized from day 21 to day 28; it was stronger in controls and increased in MS rats. Vasorelaxation to acetylcholine in NE precontracted rings did not change during the neonatal period, being similar to MS rats and lower than in controls. Insulin-induced increase in contraction elicited by KCl increased from day 12 to day 28 and increased from control to MS rats. There is a postnatal critical window in vasoreactivity that might predispose to cardiovascular diseases in adults.

Nutritional developmental epigenomics: immediate and long-lasting effects

The phenotype of an individual is the result of complex interactions between genome, epigenome and current, past and ancestral environment leading to a lifelong remodelling of the epigenomes. The genetic information expression contained in the genome is controlled by labile chromatin-associated epigenetic marks. Epigenetic misprogramming during development is widely thought to have a persistent effect on the health of the offspring and may even be transmitted to the next generation. The epigenome serves as an interface between the environment and the genome. Dietary factors, including folate involved in C1 metabolism, and other social and lifestyle exposures have a profound effect on many aspects of health including ageing and do so, at least partly, through interactions with the genome, which result in altered gene expression with consequences for cell function and health throughout the life course. Depending on the nature and intensity of the environmental insult, the critical spatiotemporal windows and developmental or lifelong processes involved, epigenetic alterations can lead to permanent changes in tissue and organ structure and function or to phenotypic changes that can (or cannot) be reversed using appropriate epigenetic tools. Moreover, the flexibility of epigenetic marks may make it possible for environmental, nutritional and hormonal factors or endocrine disruptors to alter, during a particular spatiotemporal window in a sex-specific manner, the sex-specific methylation or demethylation of specific CpG and/or histone modifications underlying sex-specific expression of a substantial proportion of genes. Moreover, genetic factors, the environment and stochastic events change the epigenetic landscape during the lifetime of an individual. Epigenetic alterations leading to gene expression dysregulation accumulate during ageing and are important in tumorigenesis and age-related diseases. Several encouraging trials suggest that prevention and therapy of age- and lifestyle-related diseases by individualised tailoring to optimal epigenetic diets or drugs are conceivable. However, these interventions will require intense efforts to unravel the complexity of these epigenetic, genetic and environment interactions and to evaluate their potential reversibility with minimal side effects.

Ten putative contributors to the obesity epidemic

The obesity epidemic is a global issue and shows no signs of abating, while the cause of this epidemic remains unclear. Marketing practices of energy-dense foods and institutionally-driven declines in physical activity are the alleged perpetrators for the epidemic, despite a lack of solid evidence to demonstrate their causal role. While both may contribute to obesity, we call attention to their unquestioned dominance in program funding and public efforts to reduce obesity, and propose several alternative putative contributors that would benefit from equal consideration and attention. Evidence for microorganisms, epigenetics, increasing maternal age, greater fecundity among people with higher adiposity, assortative mating, sleep debt, endocrine disruptors, pharmaceutical iatrogenesis, reduction in variability of ambient temperatures, and intrauterine and intergenerational effects as contributing factors to the obesity epidemic are reviewed herein. While the evidence is strong for some contributors such as pharmaceutical-induced weight gain, it is still emerging for other reviewed factors. Considering the role of such putative etiological factors of obesity may lead to comprehensive, cause specific, and effective strategies for prevention and treatment of this global epidemic.

Metabolic programming: Role of nutrition in the immediate postnatal life

Although genes and dietary habits are generally implicated in the aetiology of the prevailing obesity epidemic, the steep increase in the incidence of obesity within a relatively short span of time suggests that other contributing factors may be at play. The role of nutritional experience during the very early periods of life is increasingly being recognized as contributing to growth and metabolic changes in later life. Epidemiological data and studies from animal models have established a strong correlation between an aberrant intrauterine environment and adult-onset disorders in offspring. The nutritional experience in the immediate postnatal life is another independent factor contributing to the development of metabolic diseases in adulthood. Although studies on the small-litter rat model have shown that overnourishment during the suckling period results in adult-onset metabolic disorders, our studies have shown that a change in the quality of calories-specifically, increased carbohydrate intake by newborn rat pups in the immediate postnatal period-results in chronic hyperinsulinaemia and adult-onset obesity. Several functional alterations in islets and in the hypothalamic energy homeostatic mechanism appear to support this phenotype. Remarkably, female rats that underwent the high-carbohydrate dietary modification as neonates spontaneously transmitted the obesity phenotype to their offspring, thus establishing a vicious generational effect. The high-carbohydrate diet-fed rat model has particular relevance in the context of the current human infant feeding practices: reduction in breast feeding and increase in formula feeding for infants, accompanied by early introduction of carbohydrate-enriched baby foods.

Metabolic effects of different protein intakes after short term undernutrition in artificially reared infant rats

BACKGROUND

Early postnatal nutrition is involved in metabolic programming. Small for gestational age and premature babies commonly receive insufficient dietary protein during the neonatal period due to nutrition intolerance, whereas high protein formulas are used to achieve catch up growth. Neither the short term, nor the long term effects of such manipulation of protein intake are known.

AIM

We hypothesized that high or low protein intake during infancy would induce metabolic alterations both during early-life and in adulthood.

METHODS

Gastrostomized neonatal rat pups received either 50% (P50%), 100% (P100%), or 130% (P130%) of the normal protein content in rat milk from the 7th to the 15th day of life (D7 to D15), when they were either sacrificed or placed with mothers for the long term study. Glucose tolerance tests (GTT) were performed at D230. Long term rats were sacrificed at D250.

RESULTS

At D15, weight of P50% pups was lower than P100% and P130% pups. Neither liver and kidney mass, nor islet beta-cell areas were altered. Brain weight (adjusted to body weight) was higher in P50% vs. P130% (p<0.05). Insulin/glucose ratio was lower in P50% vs. P130%. Expression of GLUT4 on adipocyte cell membrane and GLUT2 in liver cytosol was significantly enhanced in P50% vs. P130%. Long term, neither GTT results nor body nor organ weights differed between groups.

CONCLUSION

In neonatal rats, higher protein intakes via the enteral route led to enhanced short term weight gain, insulin resistance, and modified expression of glucose transporters. However, these differences were not sustained.

Morbidity of overweight (>or=85th percentile) in the first 2 years of life

OBJECTIVES

Our hypothesis was that morbidity related to overweight/obesity is already evident in infants and young toddlers. The major objectives of this study were (1) to assess the prevalence of overweight in a sample of hospitalized infants and (2) to assess the prevalence of morbidity in overweight infants in a community-based sample.

METHODS

The hospital admission study population included 2139 infants, <or=24 months of age, who were admitted for any reason to the pediatric department at the Bnai Zion Medical Center in 2004-2005. For the community-based sample, we identified overweight infants (>or=85th weight-for-height percentile in >or=2 measurements, >or=3 months apart), <or=24 months of age, in 8 mother and child health care facilities in the Haifa subdistrict of Israel. Parents of infants were interviewed by using a structured questionnaire.

RESULTS

We found that overweight infants (85th to 94th percentiles) had fewer admissions and fewer repeated admissions than expected. Infants of >or=95th percentile had more admissions than expected, as well as a larger number of repeated admissions. In the second part of the study, we found that rates of developmental delays (mainly delayed gross motor skills) and snoring were significantly higher in infants of >or=85th percentile. In addition, although the results were not statistically significant, infants with overweight suffered more frequently from breathing problems, such as asthma and stridor. When the mothers were asked to assess whether their child was overweight, only 31.6% of mothers of overweight children thought that the child was overweight.

CONCLUSIONS

The high admission rates for infants of >or=95th percentile and the high incidence rates of respiratory morbidity, snoring, and delayed gross motor skills in overweight infants support our hypothesis regarding early morbidity associated with overweight.

Dietary fructose during the suckling period increases body weight and fatty acid uptake into skeletal muscle in adult rats

OBJECTIVE

The suckling period is one potentially "critical" period during which nutritional intake may permanently "program" metabolism to promote increased adult body weight and insulin resistance in later life. This study determined whether fructose introduced during the suckling period altered body weight and induced changes in fatty acid transport leading to insulin resistance in adulthood in rats.

METHODS AND PROCEDURES

Pups were randomly assigned to one of four diets: suckle controls (SCs), rat milk substitute formula (Rat Milk Substitute), fructose-containing formula (Fructose), or galactose-containing formula (Galactose). Starting at weaning, all pups received the same diet; at 8 weeks of age, half of the SC rats began ingesting a diet containing 65% kcal fructose (SC-Fructose). This continued until animals were 12 weeks old and the study ended.

RESULTS

At weeks 8, 10, and 11, the Fructose group weighed more than SC and SC-Fructose groups (P < 0.05). At weeks 8 and 10 of age, the Fructose group had significantly higher insulin concentrations vs. rats in the SC-Fructose group. (3)H-Palmitate transport into vesicles from hind limb skeletal muscle was higher in Fructose vs. SC rats (P < 0.05). CD36 expression was increased in the sarcolemma but not in whole tissue homogenates from skeletal muscle from Fructose rats (P < 0.05) suggesting a redistribution of this protein associated with fatty acid uptake across the plasma membrane. This change in subcellular localization of CD36 is associated with insulin resistance in muscle.

DISCUSSION

Consuming fructose during suckling may result in lifelong changes in body weight, insulin secretion, and fatty acid transport involving CD36 in muscle and ultimately promote insulin resistance.

A review of islet of Langerhans degeneration in rodent models of type 2 diabetes

Type 2 diabetes mellitus (TTDM) is characterized by progressive loss of glucose control through multifactorial mechanisms. The search for an understanding of TTDM has relied on animal models since the realization of the importance of the pancreas in controlling plasma glucose concentration. Rodent models of TTDM are developed to express hyperglycemia and not islet degeneration per se. Degeneration of the islets of Langerhans with beta-cell loss is secondary to insulin resistance and is regarded as the more important lesion. Despite this, differences between models are seen in the development and progression of islet degeneration. Assessing the differences between the models is important to appreciate the various aspects of TTDM and understand their advantages as well as their deficiencies. Relevant animal models of TTDM provide opportunities to investigate important physiological and cell biological processes that may ultimately lead to development of targeted therapies. This article reviews the importance, advantages, and limitations of rodent models of TTDM in relation to the histopathological changes that characterize islet degeneration. Pathophysiological mechanisms that contribute to islet degeneration are also discussed and are placed into the context of changes in islet histological appearances.

Impact of early postnatal weight gain and feeding patterns on body mass index in adolescence

Postnatal weight gain may predispose to the development of obesity during childhood. The aims of this study were to study the impact of weight gain during specific periods of the first year of life and of feeding patterns on the body mass index (BMI) of adolescents. Growth records during the first 24 months of life of 88 obese and 214 non-obese 12 year-old Arab children were evaluated. Birth weight and length were similar for obese and non-obese adolescents, while the rate of breastfeeding was significantly lower in the obese group (p < 0.01). Obese adolescents demonstrated a small yet significant accelerated weight gain at 4 (p = 0.002) and 12 (p = 0.01) months of age. Weight gain during the first 2 months of life and feeding pattern were independent predictors of BMI at the age of 12 years. Thus, early postnatal weight gain is associated with obesity in adolescence, while breastfeeding seems to have a protective effect.

The role of beta-cell dysfunction in the cardiometabolic syndrome

The regulation of blood glucose levels involves a finely tuned relationship between insulin sensitivity, hepatic glucose output, and production of insulin. The cardiometabolic syndrome includes in its definition criteria a disturbance of normal glucose tolerance and implies development of both insulin resistance and beta-cell dysfunction. There is now abundant evidence pointing toward a central role of dysregulation of the beta-cell function and mass in the development of impaired glucose tolerance. Mechanisms implicated in beta-cell dysfunction include genetic abnormalities, prenatal and early postnatal insults, and environmental events along with obesity, dyslipidemia-lipotoxicity, glucotoxicity, oxidative stress, chronic low-grade inflammation, amyloid deposition, and activation of the local renin-angiotensin system. Novel therapeutic characteristics of known medications such as metformin, thiazolidinediones, angiotensin-converting enzyme inhibitors/angiotensin receptor blockers, and novel medications such as exendin-4 promise encouraging possibilities to battle against the cardiometabolic syndrome and the future development of cardiovascular disease.

Autonomic involvement in the permanent metabolic programming of hyperinsulinemia in the high-carbohydrate rat model

Exposure to a high-carbohydrate (HC) milk formula during the suckling period results in permanent metabolic programming of hyperinsulinemia in HC rats. Previous studies have shown that hyperinsulinemia in HC rats involves a programmed hyperresponsiveness to glucose. However, the immediate onset and persistence of enhanced insulin secretion throughout life suggests a role for numerous factors that control insulin secretion. Present in vivo and in vitro studies have shown a role for altered autonomic activity, including increased parasympathetic and decreased sympathetic activities, in the maintenance of hyperinsulinemia in 100-day-old HC rats. HC rats were shown to be more sensitive to cholinergic-induced potentiation of glucose-stimulated insulin secretion (GSIS) in response to acetylcholine and showed increased sensitivity to blockade of cholinergic-induced insulin secretion by the muscarinic-type 3 receptor-specific antagonist 4-diphenylacetoxy-N-methylpiperidine. In addition, HC rats were less sensitive to adrenergic-induced inhibition of insulin secretion by oxymetazoline, whereas treatment with yohimbine resulted in increased GSIS. Furthermore, HC rats showed greater reductions in plasma insulin levels after vagotomy, as well as an attenuation of yohimbine-induced potentiation of GSIS, suggesting that yohimbine-mediated changes are mediated by parasympathetic activity. Changes in autonomic regulation of GSIS are supported by increased mRNA levels of the parasympathetic signaling molecules muscarinic-type 3 receptor, phospholipase Cbeta1, and protein kinase C-alpha and decreased levels of alpha(2a)-adrenergic receptors in islets from adult HC rats. In conclusion, metabolic programming of hyperinsulinemia throughout adulthood of HC rats involves changes in autonomic activity in response to the HC dietary intervention in the suckling period.

Role of the autonomic nervous system in the development of hyperinsulinemia by high-carbohydrate formula feeding to neonatal rats

An early dietary intervention in the form of a high-carbohydrate (HC) milk formula in neonatal rat pups results in immediate onset of hyperinsulinemia. While increased insulin secretion in HC rats has been shown to be related to hypersensitivity to glucose, the immediate onset of hyperinsulinemia and its persistence throughout the suckling period suggest involvement of multiple systems that enhance insulin secretion in response to increased demand. Evidence presented here in 12-day-old HC rats indicates that altered activity of the autonomic nervous system contributes to enhanced insulin secretory responses to glucose stimulation through increased parasympathetic and decreased sympathetic signaling. Both in vivo and in vitro studies have shown that HC rats secrete significantly higher levels of insulin in response to glucose in the presence of acetylcholine, a cholinergic agonist, while sensitivity to inhibition of insulin secretion by oxymetazoline, an alpha(2a)-adrenergic receptor (alpha(2a)AR) agonist, was reduced. In addition, HC rats showed increased sensitivity to blockade of cholinergic-induced insulin secretion by the muscarinic type 3 receptor (M3R) antagonist 4-diphenylacetoxy-N-methylpiperidine methobromide, as well as increased potentiation of glucose-stimulated insulin secretion by treatment with yohimbine. Increases in islets levels of M3R, phospholipase C-beta1, and protein kinase Calpha mRNAs, as well as decreased alpha(2a)AR mRNA, in 12-day-old HC rats provide a mechanistic connection to the changes in insulin secretion seen in HC rats. In conclusion, altered autonomic regulation of insulin secretion, due to the HC nutritional intervention, contributes to the development of hyperinsulinemia in 12-day-old HC rats.

Animal models for small for gestational age and fetal programming of adult disease

Fetal growth retardation is a fetal adaptation in response to inadequate supply of oxygen and/or nutrients. Animal models of intrauterine growth retardation are an invaluable tool to question the genetic, molecular and cellular events that determine fetal growth and development. Rodent and non-litter bearing animals are mammalian system with similar embryology,anatomy and physiology to humans. Utilization of these systems has led to a greater understanding of the pathophysiology and consequences of intrauterine growth retardation. These observations are comparable to that observed in humans born small for gestational age, and are of interest because of the known association between poor fetal growth and development of adult disease. All the experimental manipulations described here have altered a number of metabolic and physiological variables, but the pattern of alterations seems to vary with the procedure and species employed. This review describes animal models for intrauterine growth retardation and assesses their potentials and limitations at aiming to improve strategies for the prevention of adult disease.

Long-term consequences of under-nutrition during suckling on glucose tolerance and lipoprotein profile in female and male rats

To determine the effect of under-nutrition during suckling in adults, at delivery female Sprague Dawley rats were allowed to lactate litters of either eight (controls) or sixteen pups each (large litter, LL). The amount of milk taken by LL pups was less than the controls and the concentration of triacylglycerols (TG) in the milk of the former was lower. The increase of both body weight and length in LL was lower than in the controls during suckling. At weaning, pups were allowed to eat ad libitum a standard diet and whereas at 20 months female body weight did not differ between LL and control rats, LL males weighed less than controls. Plasma NEFA were lower in male LL than in controls at 10 months, leptin at 10 and 16 months and TG and VLDL-TG at 20 months, with no differences in females. When 20 months old, lumbar and epididymal adipose tissue weights were lower in male LL than in controls, but not in females. The increase in plasma insulin after oral glucose load was lower in LL than in controls, both in males and females at 4 and 16 months, and only in males at 10 months, whereas the change in plasma glucose remained constant between the groups. Results indicate that both the pancreatic beta-cell function and insulin sensitivity and adipose tissue metabolism are independently programmed as a consequence of under-nutrition during suckling, the effect being more manifest for males than for females.

Restructuring of pancreatic islets and insulin secretion in a postnatal critical window

Function and structure of adult pancreatic islets are determined by early postnatal development, which in rats corresponds to the first month of life. We analyzed changes in blood glucose and hormones during this stage and their association with morphological and functional changes of alpha and beta cell populations during this period. At day 20 (d20), insulin and glucose plasma levels were two- and six-fold higher, respectively, as compared to d6. Interestingly, this period is characterized by physiological hyperglycemia and hyperinsulinemia, where peripheral insulin resistance and a high plasmatic concentration of glucagon are also observed. These functional changes were paralleled by reorganization of islet structure, cell mass and aggregate size of alpha and beta cells. Cultured beta cells from d20 secreted the same amount of insulin in 15.6 mM than in 5.6 mM glucose (basal conditions), and were characterized by a high basal insulin secretion. However, beta cells from d28 were already glucose sensitive. Understanding and establishing morphophysiological relationships in the developing endocrine pancreas may explain how events in early life are important in determining adult islet physiology and metabolism.

Developmental programming of obesity in mammals

Converging lines of evidence from epidemiological studies and animal models now indicate that the origins of obesity and related metabolic disorders lie not only in the interaction between genes and traditional adult risk factors, such as unbalanced diet and physical inactivity, but also in the interplay between genes and the embryonic, fetal and early postnatal environment. Whilst studies in man initially focused on the relationship between low birth weight and risk of adult obesity and metabolic syndrome, evidence is also growing to suggest that increased birth weight and/or adiposity at birth can also lead to increased risk for childhood and adult obesity. Hence, there appears to be increased risk of obesity at both ends of the birth weight spectrum. Animal models, including both under- and overnutrition in pregnancy and lactation lend increasing support to the developmental origins of obesity. This review focuses upon the influence of the maternal nutritional and hormonal environment in pregnancy in permanently programming appetite and energy expenditure and the hormonal, neuronal and autocrine mechanisms that contribute to the maintenance of energy balance in the offspring. We discuss the potential maternal programming 'vectors' and the molecular mechanisms that may lead to persistent pathophysiological changes resulting in subsequent disease. The perinatal environment, which appears to programme subsequent obesity, provides a potential therapeutic target, and work in this field will readily translate into improved interventional strategies to stem the growing epidemic of obesity, a disease which, once manifest, has proven particularly resistant to treatment.

Ontogeny of ingestive behavior

Review of the ontogeny of the controls of independent ingestion reveals that some of the direct and indirect controls of meal size identified in adult rats function in the first three postnatal weeks. The controls appear sequentially and some of them change their potency after they emerge. Indirect controls exerted by metabolism and adiposity do not emerge until the fourth postnatal week or later in the postweaning period. Recent experiments in rats with monogenic obesities involving the leptin and cholecystokinin receptors have demonstrated the usefulness of independent ingestion in the detection of the earliest expression of hyperphagia. Although much remains to be learned about the normal controls of independent ingestion, it is clear that it provides relevant information about the development of normal and abnormal controls of meal size in rodents that is useful for translational research into the controls of meal size in normal and obese children.

Dietary fat and fat types as early determinants of childhood obesity: a reappraisal

BACKGROUND

The growing prevalence of childhood overweight and obesity has renewed interest in determining the influence of the maternal and infant diet on the risk of developing excess fat mass later in life.

APPROACH

Review of available human and animal data reporting the effects of dietary fat and fat types early in life on adipose development.

RESULTS

Rodent studies tend to show that maternal high-fat feeding during pregnancy and lactation results in increased adiposity of the offspring. Nevertheless, today there is a lack of population-based studies investigating this potential detrimental effect of maternal high-fat intake. Most epidemiological studies, performed so far, do not find any association between the level of dietary fat intake of infants and children and body weight and/or fatness. Regarding fat types exposure to high levels of dietary n-6 fatty acids during gestation and post-natal life, has been shown to promote obesity in mice. Nevertheless, other rodent studies do not demonstrate such an effect.

CONCLUSION

There is no evidence supporting a restriction of fat intake during the first two post-natal years but the potential detrimental effects of maternal high-fat intake during gestation should be further investigated. The role of dietary fat types as early determinants of childhood obesity has so far been poorly studied. Robust evidence to support the adipogenic effects of n-6 fatty acids enriched-diets is currently lacking but this hypothesis is of importance and should be further evaluated in different animal models as well as in longitudinal human studies.

Is defective pancreatic beta-cell mass environmentally programmed in Goto-Kakizaki rat model of type 2 diabetes?: insights from crossbreeding studies during suckling period

OBJECTIVE

The Goto-Kakizaki (GK) rat is a spontaneous model of type 2 diabetes with a well established pathological pancreatic beta-cell development. Hyperglycemia experienced during early postnatal life contributes to the programming of endocrine pancreas. We have analyzed the consequences of hyperglycemic versus euglycemic suckling period for the pancreatic beta-cell mass and the in vivo glucose tolerance and insulin secretion in 4-week-old unweaned control Wistar (W), diabetic GK, and in offspring issued from crosses between normoglycemic W and diabetic GK rats.

METHODS

Mother/father crosses yielded offspring designated as follows: W/W, GK/GK, W/GK, and GK/W. In vivo glucose tolerance and insulin secretion tests were performed on males 4 weeks after birth, that is, just before weaning. Beta-cell mass was determined by immunohistochemistry and morphometry.

RESULTS

Four-week-old W/GK and GK/W rats are normoglycemic, normoinsulinemic, and display a similarly small beta-cell mass. Both W/GK and GK/W rats exhibit in vivo glucose intolerance and defective insulin secretion in response to glucose.

CONCLUSIONS

Our data obtained from crossbreeding studies during suckling period suggest that the defective pancreatic beta-cell mass is not environmentally programmed in the GK model of type 2 diabetes. Rather, they support the hypothesis that the beta-cell mass defect in the GK is linked to genetic determinism.

Adiponectin, Adipocyte Fatty Acid Binding Protein, and Epidermal Fatty Acid Binding Protein: Proteins Newly Identified in Human Breast Milk

Background: Breastfeeding may protect children from developing metabolic syndrome and other diseases later in life. We investigated novel proteins in human breast milk that might play a role in this process.

Methods: We used ELISA to measure adiponectin, adipocyte and epidermal fatty acid binding proteins (AFABP, EFABP), and leptin concentrations in human breast milk obtained from 59 mothers 48 h after initiation of lactation. Using a questionnaire and medical records, we collected information about the mothers and newborns.

Results: Mean (SE) adiponectin concentrations in breast milk were 13.7 (0.8), range 3.9–30.4 μg/L; AFABP concentrations 26.7 (4.4), range 1.2–137.0 μg/L; EFABP concentrations 18.1 (1.4), range 0.8–47.0 μg/L; and leptin concentrations 0.50 (0.05), range 0–1.37 μg/L. We found a significant correlation between AFABP and EFABP concentrations (r = 0.593, P &lt;0.0001). Maternal EFABP concentrations were significantly higher in mothers who delivered boys than in those who delivered girls [21.7 (2.3) vs 15.4 (1.7) μg/L, P = 0.028] and correlated with newborn birth weight (r = 0.266, P = 0.045). Maternal leptin correlated with body weight before pregnancy (r = 0.272, P = 0.043) and at delivery (r = 0.370, P = 0.005), body mass index before pregnancy (r = 0.397, P = 0.003) and at delivery (r = 0.498, P &lt;0.0001), body weight gain during pregnancy (r = 0.267, P = 0.047), and newborn gestational age (r = 0.266, P = 0.048). Leptin was significantly lower in mothers who delivered preterm vs term babies [0.30 (0.09) vs 0.60 (0.05) ug/L, P = 0.026].

Conclusions: Concentrations of adiponectin, AFABP, and EFABP in human breast milk are related to nutritional variables of mothers and newborns and thus may play a role in the protective effects of breastfeeding.

Early-life immune challenge: defining a critical window for effects on adult responses to immune challenge

Many aspects of mammalian physiology are functionally immature at birth and continue to develop throughout at least the first few weeks of life. Animals are therefore vulnerable during this time to environmental influences such as stress and challenges to the immune system that may permanently affect adult function. The adult immune system is uniquely sensitive to immune challenges encountered during the neonatal period, but it is unknown where the critical window for this programming lies. We subjected male Sprague-Dawley rats at postnatal day (P)7, P14, P21, and P28 to either a saline or lipopolysaccharide (LPS) injection and examined them in adulthood for differences in responses to a further LPS injection. Adult febrile and cyclooxygenase-2 responses to LPS were attenuated in rats given LPS at P14 and P21, but not in those treated at P7 or P28, while P7-LPS rats displayed lower adult body weights than those treated at other times. P28-LPS rats also tended to display enhanced anxiety in the elevated plus maze. In further experiments, we examined maternal-pup interactions, looking at the mothers' preference in two pup-retrieval tasks, and found no differences in maternal attention to LPS-treated pups. We therefore demonstrate a 'critical window' for the effects of a neonatal immune challenge on adult febrile responses to inflammation and suggest that there are other critical time points during development for the programming of adult physiology. We also show that the neonatal LPS effects on the adult immune system are not likely due to overt differences in maternal attention.

Hypercytolipidemia-induced cellular lipoapoptosis: Cytostructural and endometabolic basis of progressive organo-involution following expression of diabetes (db/db) and obese (ob/ob) mutation syndromes

Onset expression of Type 2 (NIDDM) diabetes and obesity metabolic syndromes (DOS) are characterized by premature, progressive cytoatrophy and organo-involution induced by dysregulated cellular gluco- and lipo-metabolic cascades. The consequential systemic, interstitial and intracellular hyperlipidemia disrupts normal cytointegrity and metabolic responsivity to the established hypercaloric pericellular environments. The sequential cytostructural, metabolic and endocrine disturbances associated with the development of progressive DOS-associated hypercytolipidemia compromises cellular metabolic response cascades and promotes cytochemical disturbances which culminate with nuclear lipoapoptosis and cytoatrophy. The dramatic alterations in interstitial glucose and lipid (free fatty acids/triglycerides) concentrations are recognized to influence interstitial and cytoplasmic microchemical environments, which markedly alter cellular nutrient diffusion and active trans-membrane flux rates. The progressive exacerbation of interstitial and cytoplasmic lipid imbibition has been demonstrated to be associated with DNA fragmentation by lipo-infiltration into the chromatin matrix, inducing structural disruption and physical dissolution, indexed as nuclear lipoapoptosis. Therapeutic reduction of the severity of hypercytolipidemia-induced structural and cytochemical compromise promotes the restoration of homeostatic metabolic support for normalized cytostructural indices and supportive cellular gluco- and lipo-metabolic cascades. The re-establishment of a homeostatic interstitial microenvironment moderates the severity of cytolipidemic compromise within affected cell types, reduces nuclear lipo-infiltration and DNA lipo-dissolution, resulting in the preservation of cytostructural integrity. Through the therapeutic restoration of extra- and intra-cellular microchemical environments in genetically dysregulated metabolic syndrome models, the coincident cytochemical, endocrine and metabolic disturbances associated with progressive hypercytolipidemia, resulting from the expressed systemic hypercaloric environmental and hepato-pancreatic endometabolic disturbances which characterize Type 2 (NIDDM) diabetes-obesity and metabolic (X) syndromes, may be ameliorated.

NICHD: AAP workshop on neonatology research and training areas of research in neonatal gastroenterology

Future research in neonatal and developmental gastroenterology should include inquiry well beyond finding a cure or better preventative measures against necrotizing enterocolitis. The gastrointestinal (GI) tract acts not only as a digestive-absorptive organ; it also serves major endocrine and neural functions. It encompasses a vast surface area exposed to the external environment and plays a major role in both innate and adaptive immunity. Numerous short- and long-term health benefits could be derived from a better understanding of the developing GI tract.

Composition, structure and absorption of milk lipids: a source of energy, fat-soluble nutrients and bioactive molecules

Milkfat is a remarkable source of energy, fat-soluble nutrients and bioactive lipids for mammals. The composition and content of lipids in milkfat vary widely among mammalian species. Milkfat is not only a source of bioactive lipid components, it also serves as an important delivery medium for nutrients, including the fat-soluble vitamins. Bioactive lipids in milk include triacylglycerides, diacylglycerides, saturated and polyunsaturated fatty acids, and phospholipids. Beneficial activities of milk lipids include anticancer, antimicrobial, anti-inflammatory, and immunosuppression properties. The major mammalian milk that is consumed by humans as a food commodity is that from bovine whose milkfat composition is distinct due to their diet and the presence of a rumen. As a result of these factors bovine milkfat is lower in polyunsaturated fatty acids and higher in saturated fatty acids than human milk, and the consequences of these differences are still being researched. The physical properties of bovine milkfat that result from its composition including its plasticity, make it a highly desirable commodity (butter) and food ingredient. Among the 12 major milk fatty acids, only three (lauric, myristic, and palmitic) have been associated with raising total cholesterol levels in plasma, but their individual effects are variable-both towards raising low-density lipoproteins and raising the level of beneficial high-density lipoproteins. The cholesterol-modifying response of individuals to consuming saturated fats is also variable, and therefore the composition, functions and biological properties of milkfat will need to be re-evaluated as the food marketplace moves increasingly towards more personalized diets.