Prenatal and postnatal pathways to obesity: different underlying mechanisms, different metabolic outcomes

Calorie restriction during gestation affects ovarian reserve in offspring in the mouse

The aim of this study was to investigate the effect of calorie restriction (CR) during pregnancy in mice on metabolism and ovarian function in the offspring. Pregnant female mice were divided into two groups, a control group and a CR group (n=7 in each). Mice in the CR group were fed 50% of the amount consumed by control females from Day 10 of gestation until delivery. After weaning, the offspring received diet ad libitum until 3 months of age, when ovaries were collected. Ovaries were serially cut and every sixth section was used for follicle counting. Female offspring from CR dams tended to have increased bodyweight compared with offspring from control females (P=0.08). Interestingly, fewer primordial follicles (60% reduction; P=0.001), transitional follicles (P=0.0006) and total follicles (P=0.006) were observed in offspring from CR mothers. The number of primary, secondary and tertiary follicles did not differ between the groups (P>0.05). The CR offspring had fewer DNA double-strand breaks in primary follicle oocytes (P=0.03). In summary, CR during the second half of gestation decreased primordial ovarian follicle reserve in female offspring. These findings suggest that undernutrition during the second half of gestation may decrease the reproductive lifespan of female offspring.

The significant role of carnitine and fatty acids during pregnancy, lactation and perinatal period. Nutritional support in specific groups of pregnant women

BACKGROUND & AIMS

Pregnancy is characterized by a complexity of metabolic processes that may impact fetal health and development. Women's nutrition during pregnancy and lactation is considered important for both mother and infant. This review aims to investigate the significant role of fatty acids and carnitine during pregnancy and lactation in specific groups of pregnant and lactating women.

METHODS

The literature was reviewed using relevant data bases (e.g. Pubmed, Scopus, Science Direct) and relevant articles were selected to provide information and data for the text and associated Tables.

RESULTS

Dynamic features especially of plasma carnitine profile during pregnancy and lactation, indicate an extraordinarily active participation of carnitine in the intermediary metabolism both in pregnant woman and in neonate and may also have implications for health and disease later in life. Maternal diets rich in trans and saturated fatty acids can lead to impairments in the metabolism and development of the offspring, whereas the consumption of long chain-polyunsaturated fatty acids during pregnancy plays a beneficial physiologic and metabolic role in the health of offspring.

CONCLUSIONS

Pregnant women who are underweight, overweight or obese, with gestational diabetes mellitus or diabetes mellitus and those who choose vegan/vegetarian diets or are coming from socially disadvantaged areas, should be nutritionally supported to achieve a higher quality diet during pregnancy and/or lactation.

Role of microRNA-122 in hepatic lipid metabolism of the weanling female rat offspring exposed to prenatal and postnatal caloric restriction

We examined the role of hepatocyte micro-RNA-122 and hypothalamic neuropeptides, in weanling (21d) female rats exposed to calorie restriction induced growth restriction either prenatally (IUGR), postnatally (PNGR) or both (IPGR) vs. ad lib fed controls (CON). IUGR were hyperinsulinemic, hyperleptinemic and dyslipidemic with high circulating miR-122. In contrast, PNGR and IPGR displayed insufficient glucose, insulin and leptin amidst high ketones with a dichotomy in circulating miR-122 of PNGR Collapse

Key Words

• Circadian rhythm
• Energy balance
• Fatty acid oxidation
• Hepatic fatty acid synthesis
• Hypothalamic genes
• Intra-uterine growth restriction
• microRNA-122

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MESH Headings

• Animals
• Body Weight
• Caloric Restriction/adverse effects
• Circadian Rhythm
• Energy Metabolism
• Fatty Acids/genetics
• Fatty Acids/metabolism
• Female
• Fetal Growth Retardation/etiology
• Gene Expression
• Growth Disorders/etiology
• Hypothalamus/chemistry
• Lipid Metabolism/genetics
• Lipid Metabolism/physiology
• Liver/chemistry
• Liver/metabolism
• MicroRNAs/genetics
• MicroRNAs/physiology
• Organ Size
• Pregnancy
• RNA, Messenger/analysis
• Rats
• Rats, Sprague-Dawley
• Weaning

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Grants

• R01 HD041230 NICHD NIH HHS
• R01 HD081206 NICHD NIH HHS

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Affiliation(s)

Yun Dai Department of Pediatrics and the Children's Discovery and Innovation Institute, David Geffen School of Medicine UCLA, Los Angeles, CA
Shubhamoy Ghosh Department of Pediatrics and the Children's Discovery and Innovation Institute, David Geffen School of Medicine UCLA, Los Angeles, CA
Bo-Chul Shin Department of Pediatrics and the Children's Discovery and Innovation Institute, David Geffen School of Medicine UCLA, Los Angeles, CA
Sherin U Devaskar Department of Pediatrics and the Children's Discovery and Innovation Institute, David Geffen School of Medicine UCLA, Los Angeles, CA.

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Collaborators Collapse

Predictors Linking Obesity and the Gut Microbiome (the PROMISE Study): Protocol and Recruitment Strategy for a Cross-Sectional Study on Pathways That Affect the Gut Microbiome and Its Impact on Obesity

Background

The prevalence of obesity has increased substantially over recent decades and is associated with considerable health inequalities. Although the causes of obesity are complex, key drivers include overconsumption of highly palatable, energy-dense, and nutrient-poor foods, which have a profound impact on the composition and function of the gut microbiome. Alterations to the microbiome may play a critical role in obesity by affecting energy extraction from food and subsequent energy metabolism and fat storage.

Objective

We report the study protocol and recruitment strategy of the PRedictors linking Obesity and the gut MIcrobiomE (PROMISE) study, which characterizes the gut microbiome in 2 populations with different metabolic disease risk (Pacific and European women) and different body fat profiles (normal and obese). It investigates (1) the role of gut microbiome composition and functionality in obesity and (2) the interactions between dietary intake; eating behavior; sweet, fat, and bitter taste perception; and sleep and physical activity; and their impact on the gut microbiome, metabolic and endocrine regulation, and body fat profiles.

Methods

Healthy Pacific and New Zealand (NZ) European women aged between 18 and 45 years from the Auckland region were recruited for this cross-sectional study. Participants were recruited such that half in each group had either a normal weight (body mass index [BMI] 18.5-24.9 kg/m²) or were obese (BMI ≥30.0 kg/m²). In addition to anthropometric measurements and assessment of the body fat content using dual-energy x-ray absorptiometry, participants completed sweet, fat, and bitter taste perception tests; food records; and sleep diaries; and they wore accelerometers to assess physical activity and sleep. Fasting blood samples were analyzed for metabolic and endocrine biomarkers and DNA extracted from fecal samples was analyzed by shotgun sequencing. Participants completed questionnaires on dietary intake, eating behavior, sleep, and physical activity. Data were analyzed using descriptive and multivariate regression methods to assess the associations between dietary intake, taste perception, sleep, physical activity, gut microbiome complexity and functionality, and host metabolic and body fat profiles.

Results

Of the initial 351 women enrolled, 142 Pacific women and 162 NZ European women completed the study protocol. A partnership with a Pacific primary health and social services provider facilitated the recruitment of Pacific women, involving direct contact methods and networking within the Pacific communities. NZ European women were primarily recruited through Web-based methods and special interest Facebook pages.

Conclusions

This cross-sectional study will provide a wealth of data enabling the identification of distinct roles for diet, taste perception, sleep, and physical activity in women with different body fat profiles in modifying the gut microbiome and its impact on obesity and metabolic health. It will advance our understanding of the etiology of obesity and guide future intervention studies involving specific dietary approaches and microbiota-based therapies.

Trial Registration

Australian New Zealand Clinical Trials Registry ACTRN12618000432213; https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=370874

International Registered Report Identifier (IRRID)

RR1-10.2196/14529

Dietary Patterns in New Zealand Women: Evaluating Differences in Body Composition and Metabolic Biomarkers

The combinations of food consumed together (dietary patterns) may have a greater influence on health than nutrients or food groups consumed independently. This study investigated the relationship between dietary patterns, body composition and metabolic biomarkers of premenopausal New Zealand women from three ethnic groups. In total, 408 New Zealand European, Māori and Pacific women aged 16-45 years participated in the Women's EXPLORE (EXamining Predictors Linking Obesity Related Elements) study. Participants completed a 220-item food frequency questionnaire. Several body composition parameters and metabolic biomarkers were measured. Dietary patterns were extracted by principal component analysis and dietary pattern scores were categorised into tertiles to assess links with other measured parameters. Women with higher scores for the 'refined and processed' pattern were younger, had higher body mass index, total body fat, plasma leptin and plasma insulin (p < 0.001), and lower plasma ghrelin levels (p < 0.05) than women with lower scores. In addition, more Māori (51%) and Pacific (68%) women followed the 'refined and processed' pattern, while more New Zealand European women (40%) followed the 'sweet and savoury snacking' pattern. These data show that dietary pattern analysis is a useful tool to assess links between diet and metabolic health. It further reveals interesting ethnic group-specific differences in dietary pattern use.

The role of adipokines in developmental programming: evidence from animal models

Alterations in the environment during critical periods of development, including altered maternal nutrition, can increase the risk for the development of a range of metabolic, cardiovascular and reproductive disorders in offspring in adult life. Following the original epidemiological observations of David Barker that linked perturbed fetal growth to adult disease, a wide range of experimental animal models have provided empirical support for the developmental programming hypothesis. Although the mechanisms remain poorly defined, adipose tissue has been highlighted as playing a key role in the development of many disorders that manifest in later life. In particular, adipokines, including leptin and adiponectin, primarily secreted by adipose tissue, have now been shown to be important mediators of processes underpinning several phenotypic features associated with developmental programming including obesity, insulin sensitivity and reproductive disorders. Moreover, manipulation of adipokines in early life has provided for potential strategies to ameliorate or reverse the adverse sequalae that are associated with aberrant programming and provided insight into some of the mechanisms involved in the development of chronic disease across the lifecourse.

Food restriction during pregnancy and female offspring fertility: adverse effects of reprogrammed reproductive lifespan

BACKGROUND

Food restriction during pregnancy can influence the health of the offspring during the adulthood. The aim of the present study was to examine the effect of maternal food restriction (MFR) on the reproductive performance in female rat offspring from the first (FR1) and second (FR2) generations.

METHODS

Adult virgin Wistar female rats were given free access to tap water and were fed ad libitum on standard rodent chow, were mated with virgin adult males, and then were randomly divided into two groups: controls (that was fed ad libitum ) and food-restricted group (FR, that was given only 50% of ad libitum food throughout gestation). Their first (FR1) and the second (FR2) generation of offspring were fed ad libitum and sacrificed before puberty and at adulthood. Their ovaries were removed and their histology evaluated by estimating the number of follicles (total and at various stages of folliculogenesis), and the presence of multi-nuclei oocytes and multi-oocyte follicles.

RESULTS

Total number of ovarian follicles was lower in FR1 females at week 4 in comparison with controls, while it was not different in FR2 females vs.

CONTROLS

The number of the primordial follicle was lower in FR1 and FR2 females vs. controls at both week 4 and at week 8. When compared to the controls, the follicles containing multi-nuclei oocytes were more frequent in ovaries from FR1 and FR2 females at week 4, and higher and lower respectively in ovaries form FR1 and FR2 females at week 8.

CONCLUSION

MFR affects ovarian histology by inducing the development of abnormal follicles in the ovaries in first and second generation offspring. This finding could influence the ovarian function resulting in an early pubertal onset and an early decline in reproductive lifespan.

Development of a new diet-induced obesity (DIO) model using Wistar lean rats

Obesity is an increasingly severe socioeconomic health issue worldwide. Rodents with diet-induced obesity (DIO) are widely used as models of obesity. The main aim of this study was to establish a DIO model using Wistar lean (+/+ or +/-) rats by feeding a high-fat diet (45 kcal% fat) to dams during the latter term of gestation and the lactation period. A second aim was to examine the effect of post-weaning nutrition independently of maternal nutrition. Some pups (group D) were fed the same high-fat diet after weaning, while others (group C) were fed a chow diet after weaning. In the control groups, the dams were fed only the chow diet and the pups were fed either the chow diet (group A) or high-fat diet (group B) after weaning. Between 16-21 weeks of age, group D showed the heaviest body weight and visceral adipose tissue weight among groups, in addition to glucose intolerance and high concentrations of glucose and cholesterol in plasma. Group B showed mild obesity with dysfunctions in glucose and lipid metabolism. Interestingly, group C showed mild obesity and impaired glucose tolerance, similar to the phenotype of group B. In summary, the high-fat diet challenge of dams during gestation and lactation caused an increase in adipose tissue weight and abnormalities of glucose and lipid metabolism in their adult offspring. Our results suggest the importance of both maternal and post-weaning nutrition for DIO production and provide useful DIO models.

Maternal Food Restriction during Pregnancy and Lactation Adversely Affect Hepatic Growth and Lipid Metabolism in Three-Week-Old Rat Offspring

Maternal malnutrition influences the early development of foetal adaptive changes for survival. We explored the effects of maternal undernutrition during gestation and lactation on hepatic growth and function. Sprague-Dawley rats were fed a normal or a food-restricted (FR) diet during gestation and/or lactation. We performed analyses of covariance (adjusting for the liver weight/body weight ratio) to compare hepatic growth and lipid metabolism among the offspring. Maternal FR during gestation triggered the development of wide spaces between hepatic cells and increased the expression of mammalian target of rapamycin (mTOR) in three-week-old male offspring compared with controls (both p < 0.05). Offspring nursed by FR dams exhibited wider spaces between hepatic cells and a lower liver weight/body weight ratio than control offspring, and increased mTOR expression (p < 0.05). Interestingly, the significant decrease in expression of lipogenic-related genes was dependent on carbohydrate-responsive element-binding protein, despite the increased expression of sterol regulatory element-binding protein 1 (SREBP1) (p < 0.05). This study demonstrated increased expression of key metabolic regulators (mTOR and SREBP1), alterations in lipid metabolism, and deficits in hepatic growth in the offspring of FR-treated dams.

Diet-induced obesity and prenatal undernutrition lead to differential neuroendocrine gene expression in the hypothalamic arcuate nuclei

Previously we reported that prenatal undernutrition (UN) leads to a dysregulation of appetite suppression through alterations in hypothalamic neuropeptide gene expression. In the current study, we expand our observations and investigate neuroendocrine transcriptional responses and central leptin sensitivity within the arcuate nucleus of rats exposed to prenatal UN or a postnatal high-fat diet (HF). Pregnant Wistar rats were fed a standard chow diet either ad libitum (AD) or at 30 % of AD intake throughout gestation (UN) resulting in either control or intrauterine growth-restricted female offspring. At weaning, AD offspring were fed either a chow (C) or a HF (30 % fat wt/wt) diet ad libitum for the remainder of the study, whereas UN offspring were fed a chow diet only. At ~142 days, AD and UN offspring received either recombinant rat leptin (L) or saline (S) subcutaneously for 14 days. Prenatal UN had a significant effect on hypothalamic NPY (P < 0.0001), AgRP (P < 0.01) and ObRb (P < 0.02) mRNA expression compared to AD chow-fed offspring. A postnatal HF diet had a significant effect on AgRP mRNA expression (P < 0.001), compared to AD chow-fed offspring, but no effect on NPY and ObRb expression. Leptin treatment, in both UN and HF offspring, was ineffective in reducing NPY and AgRP mRNA expression, and had no effect on ObRb expression. These findings suggest that prenatal UN and a postnatal HF diet lead to differential neuroendocrine gene expression in the hypothalamic arcuate nuclei and reduced sensitivity to leptin's anorexigenic effects.

Maternal high fructose and low protein consumption during pregnancy and lactation share some but not all effects on early-life growth and metabolic programming of rat offspring

Maternal nutritional stress during pregnancy acts to program offspring metabolism. We hypothesized that the nutritional stress caused by maternal fructose or low protein intake during pregnancy would program the offspring to develop metabolic aberrations that would be exacerbated by a diet rich in fructose or fat during adult life. The objective of this study was to characterize and compare the fetal programming effects of maternal fructose with the established programming model of a low-protein diet on offspring. Male offspring from Sprague-Dawley dams fed a 60% starch control diet, a 60% fructose diet, or a low-protein diet throughout pregnancy and lactation were weaned onto either a 60% starch control diet, 60% fructose diet, or a 30% fat diet for 15 weeks. Offspring from low-protein and fructose-fed dam showed retarded growth (P<.05) at weaning (50.3, 29.6 vs 59.1±0.8 g) and at 18 weeks of age (420, 369 vs 464±10.9 g). At 18 weeks of age, offspring from fructose dams expressed greater quantities (P<.05) of intestinal Pgc1a messenger RNA compared with offspring from control or low-protein dams (1.31 vs 0.89, 0.85; confidence interval, 0.78-1.04). Similarly, maternal fructose (P=.09) and low-protein (P<.05) consumption increased expression of Pgc1a in offspring liver (7.24, 2.22 vs 1.22; confidence interval, 2.11-3.45). These data indicate that maternal fructose feeding is a programming model that shares some features of maternal protein restriction such as retarded growth, but is unique in programming of selected hepatic and intestinal transcripts.

Moderately decreased maternal dietary energy intake during pregnancy reduces fetal skeletal muscle mitochondrial biogenesis in the pigs

BACKGROUND

Mitochondria are of major importance in oocyte and early embryo, playing a key role in maintaining energy homeostasis. Epidemiological findings indicate that maternal undernutrition-induced mitochondrial dysfunction during pregnancy is associated with the development of metabolic disorders in offspring. Here, we investigated the effects of moderately decreased maternal energy intake during pregnancy on skeletal muscle mitochondrial biogenesis in fetal offspring with pig as a model.

METHODS

Pregnant Meishan sows were allocated to a standard-energy (SE) intake group as recommended by the National Research Council (NRC; 2012) and a low-energy (LE) intake group. Fetal umbilical vein serum and longissimus muscle samples were collected for further analysis on day 90 of pregnancy.

RESULTS

Sow and fetal weights and the concentrations of serum growth hormone (GH) and glucose were reduced in LE group. Maternal LE diet decreased the messenger RNA (mRNA) expression of genes involved in mitochondrial biogenesis and function such as peroxisome proliferator-activated receptor gamma coactivator 1α (PPARGC1A), nuclear respiratory factor 1 (NRF1), mitochondrial transcription factor A (TFAM), β subunit of mitochondrial H(+)-ATP synthase (ATB5B), sirtuin 1 (Sirt1), and citrate synthase (CS). The protein expression of PPARGC1A and Sirt1, intracellular NAD(+)-to-NADH ratio, and CS activity was reduced in LE group, and accordingly, mitochondrial DNA (mtDNA) content was decreased. Moreover, copper/zinc superoxide dismutase (CuZn-SOD) expression at both mRNA and protein levels and SOD and catalase (CAT) activities were reduced in LE group as well.

CONCLUSIONS

The observed decrease in muscle mitochondrial biogenesis and antioxidant defense capacity suggests that moderately decreased maternal energy intake during pregnancy impairs mitochondrial function in fetal pigs.

Postnatal high-fat diet enhances ectopic fat deposition in pigs with intrauterine growth retardation

OBJECTIVES

Intrauterine growth retardation (IUGR) and postnatal nutrition are risk factors for adult metabolic syndrome. However, the influences of long-term high-fat diet (HFD) intake on ectopic fat deposition in non-adipose tissues in IUGR pigs remain unclear. The present study was to determine whether HFD consumption would enhance ectopic fat deposition in IUGR pigs.

METHODS

At day 28, IUGR and control pigs were fed ad libitum to either a regular diet or a HFD. Lipid store, enzymatic activities and mRNA expression of lipid metabolism-related factors in liver and semitendinosus muscle (SM) were quantified at postnatal day 178.

RESULTS

Feeding a HFD to IUGR pigs but not to control pigs significantly increased daily weight gain, carcass fat mass, plasma leptin level and lipid content and lipoprotein lipase (LPL) activity and mRNA abundances of LPL and peroxisome proliferator-activated receptor gamma (PPARγ) in liver and SM, but decreased daily feed intake and mRNA expression of hormone-sensitive lipase (LIPE) and carnitine palmitoyl transferase-1 (CPT-1) in liver and SM (P < 0.05). Compared with control pigs, IUGR pigs had a lower body weight but higher plasma levels of total cholesterol (TC) and insulin (P < 0.05). HFD-fed pigs exhibited greater body weight, plasma concentrations of triglyceride (TG), high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C), regardless of birth weight (P < 0.05).

CONCLUSION

Our results suggested that IUGR increased the vulnerability of HFD-fed pigs to ectopic fat deposition via enhanced fatty acid flux toward ectopic sites and reduced lipolysis and fatty acid oxidation.

Decreased liver triglyceride content in adult rats exposed to protein restriction during gestation and lactation: role of hepatic triglyceride utilization

We have previously demonstrated that protein restriction throughout gestation and lactation reduces liver triglyceride content in adult rat offspring. However, the mechanisms mediating the decrease in liver triglyceride content are not understood. The aim of the current study was to use a new group of pregnant animals and their offspring and determine the contribution of increased triglyceride utilization via the hepatic fatty-acid oxidation and triglyceride secretory pathways to the reduction in liver triglyceride content. Pregnant Sprague-Dawley rats received either a control or a low protein diet throughout pregnancy and lactation. Pups were weaned onto laboratory chow on day 28 and killed on day 65. Liver triglyceride content was reduced in male, but not female, low-protein offspring, both in the fed and fasted states. The reduction was accompanied by a trend towards higher liver carnitine palmitoyltransferase-1a activity, suggesting increased fatty-acid transport into the mitochondrial matrix. However, medium-chain acyl coenzyme A dehydrogenase activity within the mitochondrial matrix, expression of nuclear peroxisome proliferator activated receptor-α, and plasma levels of β-hydroxybutyrate were similar between low protein and control offspring, indicating a lack of change in fatty-acid oxidation. Hepatic triglyceride secretion, assessed by blocking peripheral triglyceride utilization and measuring serum triglyceride accumulation rate, and the activity of microsomal transfer protein, were similar between low protein and control offspring. Because enhanced triglyceride utilization is not a significant contributor, the decrease in liver triglyceride content in male low-protein offspring is likely due to alterations in liver fatty-acid transport or triglyceride biosynthesis.

Biological and Nutritional Properties of Palm Oil and Palmitic Acid: Effects on Health

A growing body of evidence highlights the close association between nutrition and human health. Fat is an essential macronutrient, and vegetable oils, such as palm oil, are widely used in the food industry and highly represented in the human diet. Palmitic acid, a saturated fatty acid, is the principal constituent of refined palm oil. In the last few decades, controversial studies have reported potential unhealthy effects of palm oil due to the high palmitic acid content. In this review we provide a concise and comprehensive update on the functional role of palm oil and palmitic acid in the development of obesity, type 2 diabetes mellitus, cardiovascular diseases and cancer. The atherogenic potential of palmitic acid and its stereospecific position in triacylglycerols are also discussed.

Offspring’s hydromineral adaptive responses to maternal undernutrition during lactation

Early development, throughout gestation and lactation, represents a period of extreme vulnerability during which susceptibility to later metabolic and cardiovascular injuries increases. Maternal diet is a major determinant of the foetal and newborn developmental environment; maternal undernutrition may result in adaptive responses leading to structural and molecular alterations in various organs and tissues, such as the brain and kidney. New nephron anlages appear in the renal cortex up to postnatal day 4 and the last anlages to be formed develop into functional nephrons by postnatal day 10 in rodents. We used a model of undernutrition in rat dams that were food-restricted during the first half of the lactation period in order to study the long-term effects of maternal diet on renal development, behaviour and neural hydromineral control mechanisms. The study showed that after 40% food restriction in maternal dietary intake, the dipsogenic responses for both water and salt intake were not altered; Fos expression in brain areas investigated involved in hydromineral homeostasis control was always higher in the offspring in response to isoproterenol. This was accompanied by normal plasma osmolality changes and typical renal histology. These results suggest that the mechanisms for the control of hydromineral balance were unaffected in the offspring of these 40% food-restricted mothers. Undernutrition of the pups may not be as drastic as suggested by dams’ restriction.

Leptin intake in suckling rats restores altered T3 levels and markers of adipose tissue sympathetic drive and function caused by gestational calorie restriction

BACKGROUND

Maternal calorie restriction during gestation in rats has been associated with altered white adipose tissue (WAT) sympathetic innervation and function in offspring. Here, we aimed to investigate whether supplementation with oral leptin (a breast milk component) throughout the lactation period may revert the aforementioned adverse programming effects.

METHODS

Three groups of male and female rats were studied at the postnatal day 25: the offspring of control dams, the offspring of 20% calorie-restricted dams during pregnancy (CR) and CR rats supplemented with physiological doses of leptin throughout lactation (CR-Leptin). Tyrosine hydroxylase (TH) levels and its immunoreactive area, and mRNA expression levels of lipid metabolism-related genes and of deiodinase iodothyronine type II (Dio2) were determined in WAT. Triiodothyronine (T3) levels were determined in the blood.

RESULTS

In CR males, leptin treatment restored the decreased TH levels and its immunoreactive area in WAT, and partially normalized expression levels of genes related to lipolysis and fatty acid oxidation (adipose triglyceride lipase, hormone-sensitive lipase, carnitine palmitoyltransferase 1b and peroxisome proliferator-activated receptor gamma coactivator 1-alpha). Leptin treatment also reverted the decreased T3 plasma levels and WAT lipoprotein lipase mRNA levels occurring in CR males and females, and the decreased Dio2 mRNA levels in CR females.

CONCLUSIONS

Leptin supplementation throughout the lactation period reverts the malprogrammed effects on WAT structure and function induced by undernutrition during pregnancy. These findings support the relevance of the intake of leptin during lactation, bearing clear characteristics of essential nutrient, and provide a strategy to treat and/or prevent the programmed trend to obesity acquired by inadequate fetal nutrition.

Metabolic and Histopathological Effects of Fructose Intake During Pregestation, Gestation and Lactation in Rats and their Offspring

OBJECTIVE

Studies have demonstrated a significant relationship between maternal fructose intake and metabolic outcome in their offspring. However, there is a paucity of data about the long-term effects of fructose intake on the offspring of fructose-fed dams. Therefore, we planned a study to evaluate the long-term effects of fructose intake on the offspring of dam rats fed a high-fructose diet.

METHODS

Sixteen virgin female Sprague-Dawley rats were divided into two groups. Group 1 received a regular diet and Group 2 a high-fructose diet. Both groups received their experimental diets for 8 weeks before conception. They were mated and continued to feed with their experimental diet during mating and during their pregnancy and lactation periods. After weaning, the offspring from each group were divided into two groups. Group 1A received a regular diet, Group 1B - a fructose diet, Group 2A - a regular diet and Group 2B received a fructose diet. After weaning, the offspring were anesthetized and blood samples were collected for biochemical analysis. Liver, kidney and retroperitoneal adipose tissue were harvested for histopathological examination. Primary antibodies against inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) were determined as early inflammation markers.

RESULTS

After weaning, while daily water consumption was found to be significantly higher in Groups 2B and 1B (p<0.01), daily laboratory chow consumption was significantly lower in Groups 1A and 2A (p<0.01). Body weight was significantly higher in Groups 1B and 2B (p<0.01). Serum glucose, triglyceride, low-density lipoprotein cholesterol and very low-density lipoprotein cholesterol levels were found to be increased and high-density lipoprotein cholesterol levels decreased in Group 2B (p<0.05). The intensities of iNOS staining in the retroperitoneal adipose tissue, COX-2 staining in the liver and both iNOS and COX-2 staining in the kidney were higher in Group 2B (p<0.05).

CONCLUSION

Based on our findings, we believe that the offspring of dams which received a high fructose intake during their pregestation, gestation and lactation periods are at risk of developing metabolic syndrome in their later life only if they continue to receive a high intake of fructose. We therefore propose that the risk of developing metabolic syndrome can probably be reduced by modifying the diet of the offspring after weaning.

Metabolic programming of adipose tissue structure and function in male rat offspring by prenatal undernutrition

Background

A number of different pathways to obesity with different metabolic outcomes are recognised. Prenatal undernutrition in rats leads to increased fat deposition in adulthood. However, the form of obesity is metabolically distinct from obesity induced through other pathways (e.g. diet-induced obesity). Previous rat studies have shown that maternal undernutrition during pregnancy led to insulin hyper-secretion and obesity in offspring, but not to systemic insulin resistance. Increased muscle and liver glycogen stores indicated that glucose is taken up efficiently, reflecting an active physiological function of these energy storage tissues. It is increasingly recognised that adipose tissue plays a central role in the regulation of metabolism and pathophysiology of obesity development. The present study investigated the cell size and endocrine responsiveness of subcutaneous and visceral adipose tissue from prenatally undernourished rats. We aimed to identify whether these adipose tissue depots contribute to the altered energy metabolism observed in these offspring.

Methods

Adipocyte size was measured in both subcutaneous (ScAT) and retroperitoneal adipose tissue (RpAT) in male prenatally ad libitum fed (AD) or prenatally undernourished (UN) rat offspring. Metabolic responses were investigated in adipose tissue explants stimulated by insulin and beta₃ receptor agonists ex vivo. Expression of markers of insulin signalling was determined by Western blot analyses. Data were analysed by unpaired t-test or Two Way ANOVA followed by Fisher’s PLSD post-hoc test, where appropriate.

Results

Adipocytes in offspring of undernourished mothers were larger, even at a lower body weight, in both RpAT and ScAT. The insulin response of adipose tissue was reduced in ScAT, and statistically absent in RpAT of UN rats compared with control. This lack of RpAT insulin response was associated with reduced expression of insulin signalling pathway proteins. Adrenergic receptor-driven lipolysis was observed in both adipose depots; however insulin failed to express its anti-lipolytic effect in RpAT in both, AD and UN offspring.

Conclusions

Metabolic dysregulation in offspring of undernourished mothers is mediated by increased adipocyte size and reduced insulin responsiveness in both ScAT and especially in RpAT. These functional and morphological changes in adipocytes were accompanied by impaired activity of the insulin signalling cascade highlighting the important role of different adipose tissue depots in the pathogenesis of metabolic disorders.

Rescue of glucocorticoid-programmed adipocyte inflammation by omega-3 fatty acid supplementation in the rat

BACKGROUND

Adverse fetal environments predispose offspring to pathologies associated with the metabolic syndrome. Previously we demonstrated that adult offspring of dexamethasone-treated mothers had elevated plasma insulin and pro-inflammatory cytokines, effects prevented by a postnatal diet enriched with omega (n)-3 fatty acids. Here we tested whether prenatal glucocorticoid excess also programmed the adipose tissue phenotype, and whether this outcome is rescued by dietary n-3 fatty acids.

METHODS

Offspring of control and dexamethasone-treated mothers (0.75 μg/ml in drinking water, day 13 to term) were cross-fostered to mothers on a standard (Std) or high n-3 (Hn3) diet at birth. Offspring remained on these diets post-weaning, and serum and retroperitoneal fat were obtained at 6 months of age (n = 5-8 per group). Serum was analysed for blood lipids and fatty acid profiles, adipocyte cross sectional area was measured by unbiased stereological analysis and adipose expression of markers of inflammation, glucocorticoid sensitivity and lipid metabolism were determined by RT-qPCR analysis.

RESULTS

Serum total fatty acid levels were elevated (P < 0.01) in male offspring of dexamethasone-treated mothers, an effect prevented by Hn3 consumption. Prenatal dexamethasone also programmed increased adipose expression of Il6, Il1b (both P < 0.05) and Tnfa (P < 0.001) mRNAs regardless of fetal sex, but again this effect was prevented (for Il6 and Il1b) by Hn3 consumption. Offspring of dexamethasone-treated mothers had increased adipose expression of Gr (P = 0.008) and Ppara (P < 0.05) regardless of sex or postnatal diet, while 11bHsd1 was upregulated in males only. The Hn3 diet increased Ppard expression and reduced adipocyte size in all offspring (both P < 0.05) irrespective of prenatal treatment.

CONCLUSIONS

Prenatal glucocorticoid exposure programmed increased expression of inflammatory markers and enhanced glucocorticoid sensitivity of adipose tissue. Partial prevention of this phenotype by high n-3 consumption indicates that postnatal dietary manipulations can limit adverse fetal programming effects on adipose tissue.

Exercise as an intervention to improve metabolic outcomes after intrauterine growth restriction

Individuals born after intrauterine growth restriction (IUGR) are at an increased risk of developing diabetes in their adult life. IUGR impairs β-cell function and reduces β-cell mass, thereby diminishing insulin secretion. IUGR also induces insulin resistance, with impaired insulin signaling in muscle in adult humans who were small for gestational age (SGA) and in rodent models of IUGR. There is epidemiological evidence in humans that exercise in adults can reduce the risk of metabolic disease following IUGR. However, it is not clear whether adult IUGR individuals benefit to the same extent from exercise as do normal-birth-weight individuals, as our rat studies suggest less of a benefit in those born IUGR. Importantly, however, there is some evidence from studies in rats that exercise in early life might be able to reverse or reprogram the long-term metabolic effects of IUGR. Studies are needed to address gaps in current knowledge, including determining the mechanisms involved in the reprogramming effects of early exercise in rats, whether exercise early in life or in adulthood has similar beneficial metabolic effects in larger animal models in which insulin resistance develops after IUGR. Human studies are also needed to determine whether exercise training improves insulin secretion and insulin sensitivity to the same extent in IUGR adults as in control populations. Such investigations will have implications for customizing the recommended level and timing of exercise to improve metabolic health after IUGR.

GCN2 in the brain programs PPARγ2 and triglyceride storage in the liver during perinatal development in response to maternal dietary fat

The liver plays a central role in regulating lipid metabolism and facilitates efficient lipid utilization and storage. We discovered that a modest increase in maternal dietary fat in mice programs triglyceride storage in the liver of their developing offspring. The activation of this programming is not apparent, however, until several months later at the adult stage. We found that the perinatal programming of adult hepatic triglyceride storage was controlled by the eIF2α kinase GCN2 (EIF2AK4) in the brain of the offspring, which stimulates epigenetic modification of the Pparγ2 gene in the neonatal liver. Genetic ablation of Gcn2 in the offspring exhibited reduced hepatic triglyceride storage and repressed expression of the peroxisome proliferator-activated receptor gamma 2 (Pparγ2) and two lipid droplet protein genes, Fsp27 and Cidea. Brain-specific, but not liver-specific, Gcn2 KO mice exhibit these same defects demonstrating that GCN2 in the developing brain programs hepatic triglyceride storage. GCN2 and nutrition-dependent programming of Pparγ2 is correlated with trimethylation of lysine 4 of histone 3 (H3K4me3) in the Pparγ2 promoter region during neonatal development. In addition to regulating hepatic triglyceride in response to modest changes in dietary fat, Gcn2 deficiency profoundly impacts the severity of the obese-diabetic phenotype of the leptin receptor mutant (db/db) mouse, by reducing hepatic steatosis and obesity but exacerbating the diabetic phenotype. We suggest that GCN2-dependent perinatal programming of hepatic triglyceride storage is an adaptation to couple early nutrition to anticipated needs for hepatic triglyceride storage in adults. However, increasing the hepatic triglyceride set point during perinatal development may predispose individuals to hepatosteatosis, while reducing circulating fatty acid levels that promote insulin resistance.

Timing of maternal exposure to a high fat diet and development of obesity and hyperinsulinemia in male rat offspring: same metabolic phenotype, different developmental pathways?

Objective. Offspring born to mothers either fed an obesogenic diet throughout their life or restricted to pregnancy and lactation demonstrate obesity, hyperinsulinemia, and hyperleptinemia, irrespective of their postweaning diet. We examined whether timing of a maternal obesogenic diet results in differential regulation of pancreatic adipoinsular and inflammatory signaling pathways in offspring. Methods. Female Wistar rats were randomized into 3 groups: (1) control (CONT): fed a control diet preconceptionally and during pregnancy and lactation; (2) maternal high fat (MHF): fed an HF diet throughout their life and during pregnancy and lactation; (3) pregnancy and lactation HF (PLHF): fed a control diet throughout life until mating, then HF diet during pregnancy and lactation. Male offspring were fed the control diet postweaning. Plasma and pancreatic tissue were collected, and mRNA concentrations of key factors regulating adipoinsular axis signaling were determined. Results. MHF and PLHF offspring exhibited increased adiposity and were hyperinsulinemic and hyperleptinemic compared to CONT. Despite a similar anthropometric phenotype, MHF and PLHF offspring exhibited distinctly different expression for key pancreatic genes, dependent upon maternal preconceptional nutritional background. Conclusions. These data suggest that despite using differential signaling pathways, obesity in offspring may be an adaptive outcome of early life exposure to HF during critical developmental windows.

Metabolic programming of obesity by energy restriction during the perinatal period: different outcomes depending on gender and period, type and severity of restriction

Epidemiological studies in humans and controlled intervention studies in animals have shown that nutritional programming in early periods of life is a phenomenon that affects metabolic and physiological functions throughout life. The phenotypes of health or disease are hence the result of the interaction between genetic and environmental factors, starting right from conception. In this sense, gestation and lactation are disclosed as critical periods. Continuous food restriction during these stages may lead to permanent adaptations with lasting effects on the metabolism of the offspring and may influence the propensity to develop different chronic diseases associated with obesity. However, the different outcomes of these adaptations on later health may depend on factors such as the type, duration, period, and severity of the exposure to energy restriction conditions, and they are, in part, gender specific. A better understanding of the factors and mechanisms involved in metabolic programming, and their effects, may contribute significantly to the prevention of obesity, which is considered to be one of the major health concerns of our time. Here, the different outcomes of maternal food restriction during gestation and lactation in the metabolic health of offspring, as well as potential mechanisms underlying these effects are reviewed.

Hepatic insulin signaling changes: possible mechanism in prenatal hypoxia-increased susceptibility of fatty liver in adulthood

Nonalcoholic fatty liver disease (NAFLD) is strongly linked to insulin resistance. Prenatal hypoxia (PH) is a risk factor in programming of insulin resistance, glucose intolerance, and metabolic dysfunctions in later life, although the mechanisms are unclear. In this study, the role of metabolic and histological changes as well as the hepatic insulin signaling mechanisms were determined in increasing susceptibility of NAFLD in the fetus and offspring exposed to PH. Pregnant rats exposed to hypoxia (O(2) 10%) during pregnancy demonstrated decreased fetal body and liver weight as well as liver to body weight ratio, whereas these changes were not observed in the offspring. However, male liver to body weight ratio increased after PH stress. Microscopic analysis demonstrated that exposure to PH resulted in distorted architecture of the hepatic parenchyma cells with reduced cellularity in the fetus and offspring. Blood glucose and insulin levels were lower with enhanced insulin sensitivity and increased expression of hepatic insulin-signaling elements in the fetus. Furthermore, insulin resistance, impaired glucose homeostasis, and altered expression of insulin-signaling elements occurred in the offspring. Postnatal hypoxia increased hepatic lipid droplets and triglyceride in liver, whereas expressions of insulin-signaling elements were less in the offspring exposed to PH except glucose transporters 2. The results indicated that PH contributed to hepatocyte heteroplasia and metabolic changes that enhanced vulnerability for NAFLD in the offspring, probably via affecting insulin signaling pathway, including glucose transporters 2.

Superimposition of postnatal calorie restriction protects the aging male intrauterine growth- restricted offspring from metabolic maladaptations

Intrauterine growth restriction (IUGR) results in dysregulated glucose homeostasis and adiposity in the adult. We hypothesized that with aging, these perturbations will wane, and superimposition of postnatal growth restriction (PNGR) on IUGR [intrauterine and postnatal growth restriction (IPGR)] will reverse the residual IUGR phenotype. We therefore undertook hyperinsulinemic-euglycemic clamp, energy balance, and physical activity studies during fed, fasted, and refed states, in light and dark cycles, on postweaned chow diet-fed more than 17-month aging male IUGR, PNGR, and IPGR vs. control (CON) rat offspring. Hyperinsulinemic-euglycemic clamp revealed similar whole-body insulin sensitivity and physical activity in the nonobese IUGR vs. CON, despite reduced heat production and energy expenditure. Compared with CON and IUGR, IPGR mimicking PNGR was lean and growth restricted with increased physical activity, O(2) consumption (VO(2)), energy intake, and expenditure. Although insulin sensitivity was no different in IPGR and PNGR, skeletal muscle insulin-induced glucose uptake was enhanced. This presentation proved protective against the chronologically earlier (5.5 months) development of obesity and dysregulated energy homeostasis after 19 wk on a postweaned high-fat diet. This protective role of PNGR on the metabolic IUGR phenotype needs future fine tuning aimed at minimizing unintended consequences.

Fetal liver blood flow distribution: role in human developmental strategy to prioritize fat deposition versus brain development

Among primates, human neonates have the largest brains but also the highest proportion of body fat. If placental nutrient supply is limited, the fetus faces a dilemma: should resources be allocated to brain growth, or to fat deposition for use as a potential postnatal energy reserve? We hypothesised that resolving this dilemma operates at the level of umbilical blood distribution entering the fetal liver. In 381 uncomplicated pregnancies in third trimester, we measured blood flow perfusing the fetal liver, or bypassing it via the ductus venosus to supply the brain and heart using ultrasound techniques. Across the range of fetal growth and independent of the mother's adiposity and parity, greater liver blood flow was associated with greater offspring fat mass measured by dual-energy X-ray absorptiometry, both in the infant at birth (r = 0.43, P<0.001) and at age 4 years (r = 0.16, P = 0.02). In contrast, smaller placentas less able to meet fetal demand for essential nutrients were associated with a brain-sparing flow pattern (r = 0.17, p = 0.02). This flow pattern was also associated with a higher degree of shunting through ductus venosus (P = 0.04). We propose that humans evolved a developmental strategy to prioritize nutrient allocation for prenatal fat deposition when the supply of conditionally essential nutrients requiring hepatic inter-conversion is limited, switching resource allocation to favour the brain if the supply of essential nutrients is limited. Facilitated placental transfer mechanisms for glucose and other nutrients evolved in environments less affluent than those now prevalent in developed populations, and we propose that in circumstances of maternal adiposity and nutrient excess these mechanisms now also lead to prenatal fat deposition. Prenatal developmental influences play important roles in the human propensity to deposit fat.

Early postnatal caloric restriction protects adult male intrauterine growth-restricted offspring from obesity

Postnatal ad libitum caloric intake superimposed on intrauterine growth restriction (IUGR) is associated with adult-onset obesity, insulin resistance, and type 2 diabetes mellitus (T2DM). We hypothesized that this paradigm of prenatal nutrient deprivation-induced programming can be reversed with the introduction of early postnatal calorie restriction. Ten-month-old male rats exposed to either prenatal nutrient restriction with ad libitum postnatal intake (IUGR), pre- and postnatal nutrient restriction (IPGR), or postnatal nutrient restriction limited to the suckling phase (50% from postnatal [PN]1 to PN21) (PNGR) were compared with age-matched controls (CON). Visceral adiposity, metabolic profile, and insulin sensitivity by hyperinsulinemic-euglycemic clamps were examined. The 10-month-old male IUGR group had a 1.5- to 2.0-fold increase in subcutaneous and visceral fat (P < 0.0002) while remaining euglycemic, insulin sensitive, inactive, and exhibiting metabolic inflexibility (Vo(2)) versus CON. The IPGR group remained lean, euglycemic, insulin sensitive, and active while maintaining metabolic flexibility. The PNGR group was insulin sensitive, similar to IPGR, but less active while maintaining metabolic flexibility. We conclude that IUGR resulted in obesity without insulin resistance and energy metabolic perturbations prior to development of glucose intolerance and T2DM. Postnatal nutrient restriction superimposed on IUGR was protective, restoring metabolic normalcy to a lean and active phenotype.

Desnutrição perinatal e o controle hipotalâmico do comportamento alimentar e do metabolismo do músculo esquelético

A deficiência de nutrientes durante os períodos críticos do desenvolvimento tem sido associada com maior risco para desenvolver obesidade e diabetes Mellitus na vida adulta. Um dos mecanismos propostos refere-se à regulação do comportamento alimentar e às alterações do metabolismo energético do músculo esquelético. Recentemente, tem sido proposta a existência de uma comunicação entre o hipotálamo e o músculo esquelético a partir de sinais autonômicos que podem explicar as repercussões da desnutrição perinatal. Assim, esta revisão tem como objetivo discutir as repercussões da desnutrição perinatal sobre o comportamento alimentar e o metabolismo energético muscular e a comunicação existente entre o hipotálamo e o músculo via sinais adrenérgicos. Foram utilizadas as bases de dados MedLine/PubMed, Lilacs e Bireme, com publicações entre 2000 e 2011. Os termos de indexação utilizados foram: feeding behavior, energy metabolism, protein malnutrition, developmental plasticity, skeletal muscle e autonomic nervous system. Concluiu-se que a desnutrição perinatal pode atuar no controle hipotalâmico do comportamento alimentar e no metabolismo energético muscular, e a comunicação hipotálamo-músculo pode favorecer o desenvolvimento de obesidade e comorbidades durante o desenvolvimento.

Obesity and the developmental origins of health and disease

The concept that environmental stimuli imparted on a developing organism have the potential to affect both its short- and long-term developmental profiles is intuitively appealing and, more importantly, supported by a growing body of experimental and observational evidence. A number of groups have posited model hypotheses in tandem with experimental data, linking extrinsic factors to the development of a host of human diseases. Here, we review the evolution of 'the developmental origins of health and disease' as a concept and discuss recent advances in the association of specific stimuli to obesity, an epidemic cause of human morbidity and mortality.

Postnatal development of metabolic flexibility and enhanced oxidative capacity after prenatal undernutrition

Metabolic flexibility is the body's ability to adapt to changing energy demand and nutrient supply. Maternal undernutrition causes growth restriction at birth and subsequent obesity development. Intriguingly, metabolic flexibility is maintained due to adaptations of muscle tissue. The aim of the present study was to investigate developmental pathways of these adaptive changes. Wistar rats received standard chow at either ad libitum (AD) or 30% of ad libitum intake (UN) throughout pregnancy. At all ages, metabolic status indicated similar insulin sensitivity in AD and UN offspring despite the development of adiposity in UN offspring at weaning. Type IIA fiber size was reduced in soleus muscle of UN offspring at weaning and they had a higher percentage of type I fibers in adulthood with a concomitantly higher oxidative capacity. Plasticity of muscle was present during the postnatal period and proposes novel pathways for the dynamic development of metabolic flexibility throughout postnatal life.

Early onset of fatty liver in growth-restricted rat fetuses and newborns

Intrauterine growth-restricted (IUGR) newborns have increased risk of adult metabolic syndrome, including fatty liver. However, it is unclear whether the fatty liver development is "programmed" or secondary to the accompanying obesity. In this study, we examined hepatic lipid accumulation and lipid-regulatory factors (sterol regulatory element-binding protein-1c and fatty acid synthase) in IUGR and Control fetal (embryonic day 20; e20) and newborn (postnatal day 1; p1) rat pups. Notably, despite of in utero undernutrition state, IUGR fetuses demonstrated "fatty liver" with upregulation of these lipogenic indices at as early as e20. Both IUGR and Control newborns exhibited the same extent of massive increase in hepatic lipid content, whereas IUGR newborns continued to exhibit upregulated lipogenic indices. The persistent upregulation of the lipogenic indices in fetal and newborn IUGR suggests that fatty liver is gestationally programmed. Our study suggested that IUGR offspring were born with an altered metabolic life strategy of increased fuel/lipid storage which could be a distinct metabolic pathway of the thrifty phenotype.

Early and post-weaning malnutrition impairs alpha-MSH expression in the hypothalamus: a possible link to long-term overweight

The present study explored the effects of early and post-weaning malnutrition and nutritional rehabilitation on orexigenic (orexin (ORX) and neuropeptide Y (NPY)) and anorexigenic peptides (alpha-melanocyte stimulating hormone (alpha-MSH)) expressed in hypothalamic nuclei. Male Wistar rats were malnourished during gestation-lactation (MGL) or from weaning to post-natal day 55 (MPW; P55). Two groups of rats were rehabilitated with a balanced diet until P90 (MGL-R and MPW-R, respectively). After a glucose tolerance test (GTT) brains were processed for immunohistochemistry. Malnourished groups were hyperglycemic after GTT. ORX expression did not display any difference. Only MGL rats showed increased NPY immunoreactivity in ARC and PVN nuclei, and both malnourished groups showed low alpha-MSH expression in the PVN and DMH, as compared with their controls. After nutritional rehabilitation rats showed normal GTT, increased rate of body and adipose tissue weights and high proportion of food ingestion. Both rehabilitated groups maintained low alpha-MSH expression in the PVN, indicating a deleterious long-lasting effect.

Pre- and postnatal methyl deficiency in the rat differentially alters glucose homeostasis

BACKGROUND/AIMS

Early-life methyl-donor deficiency is implicated in growth restriction and later-life development of type 2 diabetes mellitus. We ascertained whether dietary methyl-donor deficiency in the mother during pregnancy or during postweaning growth in the rat would impair glucose homeostasis, insulin secretion and pancreatic endocrine development in young adults.

METHODS

Effects of maternal methyl deficiency (90% deficiency in methionine, folate and choline) were compared with those of postweaning methyl deficiency and with control diets for effects on growth, impaired glucose tolerance, insulin secretion and pancreas development in offspring. Studies focussed on male offspring, which have been shown more susceptible to early-life influences on later disease development.

RESULTS

Prenatal methyl deficiency delayed delivery, restricted birthweight by 22%, reduced litter size by 33% and increased offspring mortality to 23% shortly after birth. It reduced relative endocrine pancreatic mass in adult male offspring to 46% of endocrine mass in controls, but only mildly impaired their glucose tolerance and insulin secretion. In contrast, postweaning methyl deficiency restricted growth of male rats and reduced relative pancreatic endocrine mass (-40%), but improved their glucose tolerance, despite decreased insulin secretion.

CONCLUSION

It is clear that the global undernutrition (UN) during pregnancy in rodents alters glucose metabolism in adult offspring. It has been hypothesised that alterations in epigenetic mechanisms may underlie this phenotype. However, removing all methyl donors during pregnancy, which are essential for epigenetic processes in development, did not cause any alteration in glucose metabolism in offspring as seen in the global UN model.

Developmental programming of energy balance and its hypothalamic regulation

Developmental programming is an important physiological process that allows different phenotypes to originate from a single genotype. Through plasticity in early life, the developing organism can adopt a phenotype (within the limits of its genetic background) that is best suited to its expected environment. In humans, together with the relative irreversibility of the phenomenon, the low predictive value of the fetal environment for later conditions in affluent countries makes it a potential contributor to the obesity epidemic of recent decades. Here, we review the current evidence for developmental programming of energy balance. For a proper understanding of the subject, knowledge about energy balance is indispensable. Therefore, we first present an overview of the major hypothalamic routes through which energy balance is regulated and their ontogeny. With this background, we then turn to the available evidence for programming of energy balance by the early nutritional environment, in both man and rodent models. A wealth of studies suggest that energy balance can indeed be permanently affected by the early-life environment. However, the direction of the effects of programming appears to vary considerably, both between and within different animal models. Because of these inconsistencies, a comprehensive picture is still elusive. More standardization between studies seems essential to reach veritable conclusions about the role of developmental programming in adult energy balance and obesity.

Moderate caloric restriction during gestation in rats alters adipose tissue sympathetic innervation and later adiposity in offspring

Maternal prenatal undernutrition predisposes offspring to higher adiposity in adulthood. Mechanisms involved in these programming effects, apart from those described in central nervous system development, have not been established. Here we aimed to evaluate whether moderate caloric restriction during early pregnancy in rats affects white adipose tissue (WAT) sympathetic innervation in the offspring, and its relationship with adiposity development. For this purpose, inguinal and retroperitoneal WAT (iWAT and rpWAT, respectively) were analyzed in male and female offspring of control and 20% caloric-restricted (from 1-12 d of pregnancy) (CR) dams. Body weight (BW), the weight, DNA-content, morphological features and the immunoreactive tyrosine hydroxylase and Neuropeptide Y area (TH+ and NPY+ respectively, performed by immunohistochemistry) of both fat depots, were studied at 25 d and 6 m of age, the latter after 2 m exposure to high fat diet. At 6 m of life, CR males but not females, exhibited greater BW, and greater weight and total DNA-content in iWAT, without changes in adipocytes size, suggesting the development of hyperplasia in this depot. However, in rpWAT, CR males but not females, showed larger adipocyte diameter, with no changes in DNA-content, suggesting the development of hypertrophy. These parameters were not different between control and CR animals at the age of 25 d. In iWAT, both at 25 d and 6 m, CR males but not females, showed lower TH(+) and NPY(+), suggesting lower sympathetic innervation in CR males compared to control males. In rpWAT, at 6 m but not at 25 d, CR males but not females, showed lower TH(+) and NPY(+). Thus, the effects of caloric restriction during gestation on later adiposity and on the differences in the adult phenotype between internal and subcutaneous fat depots in the male offspring may be associated in part with specific alterations in sympathetic innervation, which may impact on WAT architecture.

Maternal protein restriction during pregnancy and lactation in rats imprints long-term reduction in hepatic lipid content selectively in the male offspring

Maternal protein restriction during pregnancy and lactation reduces whole body lipid stores and alters lipid homeostasis in the adult offspring. Lipid homeostasis in the body is regulated, in part, by the liver via the metabolic processes of synthesis and utilization of lipids. The present study tested the hypothesis that maternal protein restriction will imprint changes in hepatic lipid metabolism and thereby alter the hepatic lipid content of the adult offspring. Pregnant rats were fed purified diets containing 19% protein (control group) or 8% protein (low-protein group) throughout pregnancy and lactation. On day 28, pups from both groups were weaned onto regular laboratory chow. On days 65 and 150, male and female pups from each litter in both groups were killed and blood and liver collected. Maternal protein restriction was found to reduce birth weight and produce long-term reduction in the body weight of the offspring. On day 65, liver triglyceride content was decreased by 40% in the male offspring that were fed a low-protein diet. The reduction in liver triglyceride content persisted until day 150, at which time it was accompanied by decreases in hepatic cholesterol content. No such changes were observed in the female offspring. To determine if the alterations in liver lipid content resulted in compensatory changes in liver carbohydrate stores, hepatic glycogen content was measured in male offspring. Hepatic glycogen content was similar between the 2 groups on days 65 and 150. In conclusion, the present study in rats showed that maternal protein restriction during pregnancy and lactation imprints long-term changes in hepatic lipid content selectively in the male offspring.

Moderate caloric restriction during gestation results in lower arcuate nucleus NPY- and alphaMSH-neurons and impairs hypothalamic response to fed/fasting conditions in weaned rats

AIM

We aimed to characterize the developmental programming effects of moderate caloric restriction during early pregnancy on factors involved in hypothalamic control of energy balance.

METHODS

Twenty-five-days-old offspring Wistar rats from 20% caloric restricted dams (from 1 to 12 days of pregnancy) (CR) and from control dams were studied under fed and 12 h fasting conditions. Morphometric studies on arcuate nucleus (ARC) and determinations of circulating parameters and hypothalamic levels of neuropeptide Y (NPY), proopiomelanocortin (POMC), long-form leptin receptor (ObRb), insulin receptor (InsR) and suppressor of cytokine signalling-3 (SOCS-3) mRNA were performed.

RESULTS

CR animals did not show different body weight with respect to their controls, but presented higher food intake. They exhibited lower neuropeptide Y- and alpha-melanocyte-stimulating hormone-neurons (decreases of 18 and 13% in males, and 10 and 18% in females respectively) and lower total cells (decrease of 3% in males and 18% in females) in ARC. Under fed conditions, CR animals presented lower circulating leptin and ghrelin levels (decreases of 37 and 43% in males, and 15 and 34% in females respectively); furthermore, hypothalamic POMC, NPY (only in females), ObRb and InsR mRNA levels were reduced (39, 16 and 26% in males, and 112, 33, 61 and 56% in females), and those of SOCS-3 were increased (86% in males and 74% in females). Unlike control animals, under fasting conditions, ObRb, InsR and POMC mRNA levels did not decrease in CR females, and NPY mRNA decreased instead of increase in CR males.

CONCLUSIONS

Moderate caloric restriction during gestation affects offspring hypothalamic structure and function, impairing its response to fed/fasting conditions, which suggests a predisposition to insulin and leptin resistance.

Effect of intrauterine undernutrition during late gestation on pancreatic beta cell mass

We analyzed the effect of low birth weight on pancreatic beta cell mass. We used pregnant C57BL6J mice, and we reduced their food supply by 30% during the late gestational period and examined the changes in the metabolism and pancreatic beta cell mass. Pancreatic beta cell mass at birth was greatly decreased in the mice of the food restriction group (RG) as compared to the mice of the control group (CG). The body weight of RG mice exhibited a "catch-up growth" pattern and became equivalent to that of CG mice 7 days after birth, and thereafter exceeded that of CG mice; however, the pancreatic beta cell mass in RG mice remained lower than that in CG mice at the age of 4 weeks. A high-fat diet significantly increased the pancreatic beta cell mass in RG mice as compared to that in CG mice at 12 weeks of age. However, RG mice fed on high-fat diets tended to exhibit a decrease in the pancreatic beta cell mass at approximately 20 weeks of age. The plasma insulin concentrations also tended to be decreased in RG mice after 24 weeks of age as compared to those of CG mice. These results thus indicate that the growth of pancreatic beta cells is insufficient in RG mice, and pancreatic beta cell failure can easily develop as a consequence of insulin resistance.

Shaping adult phenotypes through early life environments

A major question in the biology of stress and environmental adaptation concerns the neurobiological basis of how neuroendocrine systems governing physiological regulatory mechanisms essential for life (metabolism, immune response, organ function) become harmful. The current view is that a switch from protection to damage occurs when vulnerable phenotypes are exposed to adverse environmental conditions. In accordance with this theory, sequelae of early life social and environmental stressors, such as childhood abuse, neglect, poverty, and poor nutrition, have been associated with the emergence of mental and physical illness (i.e., anxiety, mood disorders, poor impulse control, psychosis, and drug abuse) and an increased risk of common metabolic and cardiovascular diseases later in life. Evidence from animal and human studies investigating the associations between early life experiences (including parent-infant bonding), hypothalamus-pituitary-adrenal axis activity, brain development, and health outcome provide important clues into the neurobiological mechanisms that mediate the contribution of stressful experiences to personality development and the manifestation of illness. This review summarizes our current molecular understanding of how early environment influences brain development in a manner that persists through life and highlights recent evidence from rodent studies suggesting that maternal care in the first week of postnatal life establishes diverse and stable phenotypes in the offspring through epigenetic modification of genes expressed in the brain that shape neuroendocrine and behavioral stress responsivity throughout life.

Fructose and saturated fats predispose hyperinsulinemia in lean male rat offspring

BACKGROUND

Early exposure to suboptimal nutrition during perinatal period imposes risk to metabolic disorders later in life. Fructose intake has been associated with increases in de novo lipogenesis, dyslipidemia, insulin resistance, and obesity. Excess consumption of saturated fat is associated with metabolic disorders.

AIM OF THE STUDY

Objective of this animal study was to investigate morphological, metabolic, and endocrine phenotypes of male offspring born to dams consuming diets containing either 30% fructose, 9.9% coconut fat and 0.5% cholesterol (F + SFA) or 30% glucose, and 11% corn oil (C), 1 month before conception and during gestation and nursing.

METHODS

Proven male and female Sprague Dawley breeders were fed ad libitum with either F + SFA or C diet throughout the study. At weaning, five male pups from each group were sacrificed for determining morphological phenotypes. The other five male offspring from each group were rehabilitated to the C diet for an additional 12 weeks. At the age of 15 weeks, morphological phenotypes and blood biochemistries [glucose, insulin, growth hormone (GH), insulin-like growth factor-1 (IGF-1), corticosterone, and testosterone] of male adult offspring were then assessed.

RESULTS

Body weight (BW) and body length of the F + SFA male adult offspring was slightly smaller than the C. The BW-adjusted epididymal and retroperitoneal fat depots of the F + SFA adult offspring were significantly 18 and 44% smaller than the C, respectively. GH and IGF-1 were not different in adult offspring between groups. Fasted plasma insulin of the F + SFA adult offspring was 64% larger than the C (P <or= 0.0001) and homeostasis model assessment value was 55% larger (P = 0.004). There were negative correlations between fat depot sizes and plasma insulin in adult offspring.

CONCLUSIONS

Our results suggest that, through fetal programming, an early exposure to both fructose and saturated fats may cause hyperinsulinemia and insulin insensitivity in the nonobese male rats later in life.

Prenatally induced changes in muscle structure and metabolic function facilitate exercise-induced obesity prevention

Effective regulation of energy metabolism is vital for the maintenance of optimal health, and an inability to make these dynamic adjustments is a recognized cause of obesity and metabolic disorders. Epidemiological and experimental studies have highlighted the role of prenatal factors in the disease process, and it is now generally accepted that maternal nutrition during pregnancy significantly influences intrauterine development, shaping postnatal health. Consequences of impaired nutrition during fetal development include intrauterine growth restriction (IUGR) and subsequent obesity development in adult life. We have previously shown that prenatal undernutrition has a lasting effect on behavior, with IUGR offspring expressing a higher preference for voluntary exercise, and moderate daily exercise preventing obesity development. The present study investigated skeletal muscle structure in IUGR offspring and how moderate daily exercise drives changes in metabolic pathways that promote obesity prevention. Pregnant Wistar rats were either fed chow ad libitum or undernourished, generating control or IUGR offspring respectively. Although red muscle structure indicated higher oxidative capacity in IUGR offspring, obesity prevention was not due to increased fatty acid oxidation, indicated by decreased peroxisomal proliferator-activated receptor-gamma coactivator 1 and carnitine-palmitoyltransferase 1 expression. In contrast, increased protein kinase Czeta expression and glycogen content in white muscle of exercised IUGR offspring suggests an enhanced capacity for anaerobic utilization of glucose. Furthermore, exercise-induced lactate accumulation was effectively prevented by stimulation of a lactate shuttle, driven by the increases in monocarboxylate transporters-4 and -1 in white muscle. This enhanced metabolic flexibility in IUGR offspring may facilitate muscle contractile performance and therefore support moderate daily exercise for effective obesity prevention.