Diet-Induced Maternal Obesity Alters Insulin Signalling in Male Mice Offspring Rechallenged with a High-Fat Diet in Adulthood

Sex-Dependent Variations in Hypothalamic Fatty Acid Profile and Neuropeptides in Offspring Exposed to Maternal Obesity and High-Fat Diet

Maternal obesity and/or high-fat diet (HF) consumption can disrupt appetite regulation in their offspring, contributing to transgenerational obesity and metabolic diseases. As fatty acids (FAs) play a role in appetite regulation, we investigated the maternal and fetal levels of FAs as potential contributors to programmed hyperphagia observed in the offspring of obese dams. Female mice were fed either a control diet (CT) or HF prior to mating, and fetal and maternal blood and tissues were collected at 19 days of gestation. Elevated levels of linoleic acid were observed in the serum of HF dams as well as in the serum of their fetuses. An increased concentration of eicosadienoic acid was also detected in the hypothalamus of female HF-O fetuses. HF-O male fetuses showed increased hypothalamic neuropeptide Y (Npy) gene expression, while HF-O female fetuses showed decreased hypothalamic pro-opiomelanocortin (POMC) protein content. Both male and female fetuses exhibited reduced hypothalamic neurogenin 3 (NGN-3) gene expression. In vitro experiments confirmed that LA contributed to the decreased gene expression of Pomc and Ngn-3 in neuronal cells. During lactation, HF female offspring consumed more milk and had a higher body weight compared to CT. In summary, this study demonstrated that exposure to HF prior to and during gestation alters the FA composition in maternal serum and fetal serum and hypothalamus, particularly increasing n-6, which may play a role in the switch from POMC to NPY neurons, leading to increased weight gain in the offspring during lactation.

Maternal-placental axis and its impact on fetal outcomes, metabolism, and development

Maternal obesity could impact offspring's health. During "critical period" such as pregnancy insults have a significant role in developing chronic diseases later in life. Literature has shown that diet can play a major role in essential metabolic and development processes on fetal outcomes. Moreover, the placenta, an essential organ developed in pregnancy, seems to have its functions impaired based on pre-gestational and gestational nutritional status. Specifically, a high-fat diet has been shown as a potential nutritional insult that also affects the maternal-placental axis, which is involved in offspring development and outcome. Moreover, some classes of nutrients are associated with pregnancy complications such as reduced intake of micronutrients and diabetes, preeclampsia, and preterm delivery. Thus, we will summarize the current literature on maternal environment factors that impacts the placental development and consequently the fetal an offspring health, or the maternal-placental axis, and this on fetal outcomes, metabolism, and development.

Research Progress on the effects of adverse exposure during pregnancy on skeletal muscle function in offspring

Skeletal muscle plays a crucial role in maintaining metabolic function, energy homeostasis, movement function, as well as endocrine function. The gestation period is a critical stage for the myogenesis and development of skeletal muscle. Adverse environmental exposures during pregnancy would impose various effects on the skeletal muscle health of offspring. Maternal obesity during pregnancy can mediate lipid deposition in skeletal muscle of offspring by affecting fetal skeletal muscle metabolism and inflammation-related pathways. Poor dietary habits during pregnancy, such as high sugar and high fat intake, can affect the autophagy function of skeletal muscle mitochondria and reduce the quality of offspring skeletal muscle. Nutritional deficiencies during pregnancy can affect the development of offspring skeletal muscle through epigenetic modifications. Gestational diabetes may affect the function of offspring skeletal muscle by upregulating the levels of miR-15a and miR-15b in offspring. Exposure to environmental endocrine disruptors during pregnancy may impair skeletal muscle function by interfering with insulin receptor-related signaling pathways in offspring. This article reviews the research progress on effects and possible mechanisms of adverse maternal exposures during pregnancy on offspring skeletal muscle function in clinical and animal studies, aiming to provide scientific evidence for the prevention and treatment strategy of birth defects in skeletal muscle.

Leucine supplementation in maternal high-fat diet alleviated adiposity and glucose intolerance of adult mice offspring fed a postweaning high-fat diet

BACKGROUND

Combined maternal and postnatal high-fat (HF) diet intake predisposes offspring to metabolic dysregulation during adulthood. As the inhibitory effects of leucine consumption on obesity and metabolic disorders have been reported, the effects of maternal leucine supplementation on metabolic dysregulation in adult offspring were investigated.

METHODS

Female mice were exposed to a control (C) or HF diet, with or without leucine (L) supplementation (1.5%, w/v), 3 weeks before mating, during pregnancy, and during lactation (C, CL, HF, and HFL). Male offspring were exposed to an HF diet for 12 weeks after weaning (C/HF, CL/HF, HF/HF, and HFL/HF). Serum biochemical parameters were determined for both the dams and offspring. Oral glucose tolerance test and qRT-PCR analysis were used to investigate metabolic dysregulation in the offspring.

RESULTS

HFL dams exhibited higher relative adipose tissue weights than HF dams. Body weight, relative adipose tissue weight, and serum glucose levels were lower in the HFL/HF offspring than in the HF/HF offspring. Maternal leucine supplementation tended to alleviate glucose intolerance in the offspring of HF diet-fed dams. Additionally, mRNA levels of fibroblast growth factor 21 (FGF21), a hepatokine associated with glucose homeostasis, were higher in HFL/HF offspring than in HF/HF offspring and were negatively correlated with adiposity and serum glucose levels. The mRNA levels of genes encoding a FGF21 receptor complex, Fgf receptor 1 and klotho β, and its downstream targets, proliferator-activated receptor-γ co-activator 1α and sirtuin 1, were higher in adipose tissues of the HFL/HF offspring than in those of the HF/HF offspring. Serum lipid peroxide levels were lower in HFL dams than in HF dams and positively correlated with body and adipose tissue weights of offspring.

CONCLUSIONS

Leucine supplementation in HF diet-fed dams, but not in control diet-fed dams, resulted in an anti-obesity phenotype accompanied by glucose homeostasis in male offspring challenged with postnatal HF feeding. Activation of FGF21 signaling in the adipose tissue of offspring may be responsible for these beneficial effects of leucine.

Rodent models of metabolic disorders: considerations for use in studies of neonatal programming

Epidemiologically, metabolic disorders have garnered much attention, perhaps due to the predominance of obesity. The early postnatal life represents a critical period for programming multifactorial metabolic disorders of adult life. Though altricial rodents are prime subjects for investigating neonatal programming, there is still no sufficiently generalised literature on their usage and methodology. This review focuses on establishing five approach-based models of neonatal rodents adopted for studying metabolic phenotypes. Here, some modelled interventions that currently exist to avoid or prevent metabolic disorders are also highlighted. We also bring forth recommendations, guidelines and considerations to aid research on neonatal programming. It is hoped that this provides a background to researchers focused on the aetiology, mechanisms, prevention and treatment of metabolic disorders.

Effects of maternal high-fat diet on the hypothalamic components related to food intake and energy expenditure in mice offspring

Maternal exposure to a high-fat diet (HFD) during pregnancy and lactation has been related to changes in the hypothalamic circuits involved in the regulation of food intake. Furthermore, maternal HFD during the critical period of development can alter the offspring's metabolic programming with long-term repercussions. This study systematically reviewed the effects of HFD consumption during pre-pregnancy, pregnancy and/or lactation. The main outcomes evaluated were food intake; body weight; cellular or molecular aspects of peptides and hypothalamic receptors involved in the regulation of energy balance in mice. Two independent authors performed a search in the electronic databases Medline/PubMed, LILACS, Web of Science, EMBASE, SCOPUS and Sigle via Open Gray. Included were experimental studies of mice exposed to HFD during pregnancy and/or lactation that evaluated body composition, food intake, energy expenditure and hypothalamic components related to energy balance. Internal validity was assessed using the SYRCLE risk of bias. The Kappa index was measured to analyze the agreement between reviewers. The PRISMA statement was used to report this systematic review. Most studies demonstrated that there was a higher body weight, body fat deposits and food intake, as well as alterations in the expression of hypothalamic neuropeptides in offspring that consumed HFD. Therefore, the maternal diet can affect the phenotype and metabolism of the offspring, in addition to harming the hypothalamic circuits and favoring the orexigenic pathways.

Programming by maternal obesity: a pathway to poor cardiometabolic health in the offspring

There is an ever increasing prevalence of maternal obesity worldwide such that in many populations over half of women enter pregnancy either overweight or obese. This review aims to summarise the impact of maternal obesity on offspring cardiometabolic outcomes. Maternal obesity is associated with increased risk of adverse maternal and pregnancy outcomes. However, beyond this exposure to maternal obesity during development also increases the risk of her offspring developing long-term adverse cardiometabolic outcomes throughout their adult life. Both human studies and those in experimental animal models have shown that maternal obesity can programme increased risk of offspring developing obesity and adipose tissue dysfunction; type 2 diabetes with peripheral insulin resistance and β-cell dysfunction; CVD with impaired cardiac structure and function and hypertension via impaired vascular and kidney function. As female offspring themselves are therefore likely to enter pregnancy with poor cardiometabolic health this can lead to an inter-generational cycle perpetuating the transmission of poor cardiometabolic health across generations. Maternal exercise interventions have the potential to mitigate some of the adverse effects of maternal obesity on offspring health, although further studies into long-term outcomes and how these translate to a clinical context are still required.

Hepatic Epigenetic Reprogramming After Liver Resection in Offspring Alleviates the Effects of Maternal Obesity

Obesity has become a public health problem in recent decades, and during pregnancy, it can lead to an increased risk of gestational complications and permanent changes in the offspring resulting from a process known as metabolic programming. The offspring of obese dams are at increased risk of developing non-alcoholic fatty liver disease (NAFLD), even in the absence of high-fat diet consumption. NAFLD is a chronic fatty liver disease that can progress to extremely severe conditions that require surgical intervention with the removal of the injured tissue. Liver regeneration is necessary to preserve organ function. A range of pathways is activated in the liver regeneration process, including the Hippo, TGFβ, and AMPK signaling pathways that are under epigenetic control. We investigated whether microRNA modulation in the liver of the offspring of obese dams would impact gene expression of Hippo, TGFβ, and AMPK pathways and tissue regeneration after partial hepatectomy (PHx). Female Swiss mice fed a standard chow or a high-fat diet (HFD) before and during pregnancy and lactation were mated with male control mice. The offspring from control (CT-O) and obese (HF-O) dams weaned to standard chow diet until day 56 were submitted to PHx surgery. Prior to the surgery, HF-O presented alterations in miR-122, miR-370, and Let-7a expression in the liver compared to CT-O, as previously shown, as well as in its target genes involved in liver regeneration. However, after the PHx (4 h or 48 h post-surgery), differences in gene expression between CT-O and HF-O were suppressed, as well as in microRNA expression in the liver. Furthermore, both CT-O and HF-O presented a similar regenerative capacity of the liver within 48 h after PHx. Our results suggest that survival and regenerative mechanisms induced by the partial hepatectomy may overcome the epigenetic changes in the liver of offspring programmed by maternal obesity.

Hepatic microRNA modulation might be an early event to non-alcoholic fatty liver disease development driven by high-fat diet in male mice

INTRODUCTION

Metabolic alterations caused by an imbalance of macronutrient consumption are often related to the modulation of microRNAs (miRNAs), which could alter mRNAs expression profile and accelerate the development of non-alcoholic fatty liver disease (NAFLD).

AIMS

This study aimed to investigate the contribution of miRNAs in modulating early stages of NAFLD in mice submitted to a high-fat diet (HFD).

METHODS AND RESULTS

Male Swiss mice, fed either a control diet or an HFD for 1, 3, 7, 15, 30, 56 days, were assessed for metabolic alterations, gene expression and NAFLD markers. A hepatocyte cell line was used to investigate the effects of miR-370 modulation on enzymes involved in β-oxidation. Body weight and adiposity were higher after 7 days of HFD. Fasting glucose and insulin increased after 3 and 7 days of HFD, respectively. While hepatic lipid content increased from the first day on, hepatic glycogen had a decrease after 3 days of HFD consumption. miR-370 and Let-7 expression increased with acute and chronic exposure to HFD, accompanied by carnitine palmitoyltransferase 1A (Cpt1a), acyl-CoA dehydrogenase very long chain (Acadvl) and protein kinase AMP-activated Catalytic Subunit 2 (Prkaa2) downregulation, while decreased miR-122 expression was accompanied by 1-acylglycerol-3-phosphate-O-acyltransferase (Agpat) upregulation after 56 days of HFD consumption, some of them confirmed by in vitro experiments. Despite fluctuations in TNFa and IL6 mRNA levels, molecular modulation was consistent with hepatic TG and NAFLD development.

CONCLUSION

Hepatic miR-370-122-Let7 miRNA modulation could be the first insult to NAFLD development, preceding changes in glycemic homeostasis and adiposity.

Animal Foetal Models of Obesity and Diabetes - From Laboratory to Clinical Settings

The prenatal period, during which a fully formed newborn capable of surviving outside its mother's body is built from a single cell, is critical for human development. It is also the time when the foetus is particularly vulnerable to environmental factors, which may modulate the course of its development. Both epidemiological and animal studies have shown that foetal programming of physiological systems may alter the growth and function of organs and lead to pathology in adulthood. Nutrition is a particularly important environmental factor for the pregnant mother as it affects the condition of offspring. Numerous studies have shown that an unbalanced maternal metabolic status (under- or overnutrition) may cause long-lasting physiological and behavioural alterations, resulting in metabolic disorders, such as obesity and type 2 diabetes (T2DM). Various diets are used in laboratory settings in order to induce maternal obesity and metabolic disorders, and to alter the offspring development. The most popular models are: high-fat, high-sugar, high-fat-high-sugar, and cafeteria diets. Maternal undernutrition models are also used, which results in metabolic problems in offspring. Similarly to animal data, human studies have shown the influence of mothers' diets on the development of children. There is a strong link between the maternal diet and the birth weight, metabolic state, changes in the cardiovascular and central nervous system of the offspring. The mechanisms linking impaired foetal development and adult diseases remain under discussion. Epigenetic mechanisms are believed to play a major role in prenatal programming. Additionally, sexually dimorphic effects on offspring are observed. Therefore, further research on both sexes is necessary.

Maternal high-fat diet consumption programs male offspring to mitigate complications in liver regeneration

In the last decades, obesity and nonalcoholic fatty liver disease (NAFLD) have become increasingly prevalent in wide world. Fatty liver can be detrimental to liver regeneration (LR) and offspring of obese dams (HFD-O) are susceptible to NAFLD development. Here we evaluated LR capacity in HFD-O after partial hepatectomy (PHx). HFD-O re-exposed or not to HFD in later life were evaluated for metabolic parameters, inflammation, proliferation, tissue repair markers and survival rate after PHx. Increasing adiposity and fatty liver were observed in HFD-O. Despite lower IL-6 levels, Ki67 labeling, cells in S phase and Ciclin D1/PCNA protein content, a lower impact on survival rate was found after PHx, even when re-exposed to HFD. However, no difference was observed between offspring of control dams (SC-O) and HFD-O after surgery. Although LR impairment is dependent of steatosis development, offspring of obese dams are programmed to be protected from the damage promoted by HFD.

Effect of maternal apical periodontitis on the final step of insulin signalling and inflammatory pathway in the adult male offspring of rats

AIM

To evaluate the final step of insulin signalling, inflammatory pathway (related to the inhibition of insulin signalling), peroxisome proliferator-activated receptor-gamma coactivator 1α (PGC-1α) protein content and DNA methylation in the Slc2a4 gene promoter region in the skeletal muscle of adult male offspring of rats with apical periodontitis (AP) in a single tooth or in four teeth.

METHODOLOGY

Female Wistar rats were distributed into three groups: a control group, a group with one tooth with AP and a group with four teeth with AP. Thirty days after induction of AP, female rats from all groups were mated with healthy male rats. When male offspring reached 75 days of age, the following analyses were performed in the gastrocnemius muscle (GM): insulin-stimulated Akt serine and threonine phosphorylation status; NF-κB p50 and p65 subunits phosphorylation status; GLUT4, TNF-α and PGC-1α protein content by Western blotting; GLUT4 and TNF-α gene expression by real-time polymerase chain reaction (PCR); and DNA methylation in the Slc2a4 gene promoter region by restriction digestion and real-time PCR. Analysis of variance was performed, followed by Tukey's post hoc test. p values <.05 were considered to be statistically significant.

RESULTS

Maternal AP in four teeth decreased insulin-stimulated Akt serine and threonine phosphorylation status, reduced GLUT4 gene expression and its protein content, and increased NF-κB p50 and p65 subunits phosphorylation status in the GM of adult offspring. There were no alterations in the parameters analysed in the GM of adult offspring of rats with AP in a single tooth. In addition, maternal AP did not affect TNF-α gene expression and its protein content, PGC-1α protein content and DNA methylation in the Slc2a4 gene promoter region in the GM of adult offspring.

CONCLUSIONS

Maternal AP in four teeth was associated with impairment in the final step of insulin signalling in the GM of adult male offspring in rats. An increase in NF-κB activity may be involved in this decrease in insulin signalling. This study demonstrates the impact of maternal AP on the health of offspring, demonstrating the importance of maintaining adequate maternal oral health to prevent diseases in adult offspring in rats.

Milk Polar Lipids Supplementation to Obese Rats During Pregnancy and Lactation Benefited Skeletal Outcomes of Male Offspring

SCOPE

Dietary intervention to obese dams during pregnancy and lactation period provides avenues for improving metabolic profiles of the offspring. In the current study, the effects of polar lipids-enriched milk fat globule membrane (MFGM-PL) supplementation to obese dams during pregnancy and lactation on the skeletal outcomes of male offspring are investigated.

METHODS AND RESULTS

MFGM-PL is supplemented to obese rats induced by high-fat diet during pregnancy and lactation at a dose of 400 mg kg-1 body weight. Results show that maternal MFGM-PL supplementation significantly ameliorates the stunted skeletal growth of male offspring at weaning. In adulthood offspring, maternal MFGM-PL supplementation protects against high-fat diet (HFD)-induced bone microstructure degeneration and bone marrow adipocyte accumulation. Further investigation shows that maternal supplementation of MFGM-PL significantly ameliorates insulin resistance and increases the mRNA expression of growth hormone releasing hormone (GHRH) in the hypothalamus of HFD offspring. The growth hormone (GH)/insulin-like growth factor-1 (IGF-1) axis is subsequently enhanced in MFGM-PL + HFD offspring, contributing to the beneficial skeletal outcomes.

CONCLUSION

The findings suggest that maternal MFGM-PL supplementation of HFD dam during pregnancy and lactation shows desirable effects on fetal skeletal development, with lasting beneficial programming impacts on skeletal outcomes of offspring.

Offspring of Obese Dams Exhibit Sex-Differences in Pancreatic Heparan Sulfate Glycosaminoglycans and Islet Insulin Secretion

Offspring of obese mothers suffer higher risks of type 2 diabetes due to increased adiposity and decreased β cell function. To date, the sex-differences in offspring islet insulin secretion during early life has not been evaluated extensively, particularly prior to weaning at postnatal day 21 (P21). To determine the role of maternal obesity on offspring islet insulin secretion, C57BL/6J female dams were fed chow or western diet from 4 weeks prior to mating to induce maternal obesity. First, offspring of chow-fed and obese dams were evaluated on postnatal day 21 (P21) prior to weaning for body composition, glucose and insulin tolerance, and islet phasic insulin-secretion. Compared to same-sex controls, both male and female P21 offspring born to obese dams (MatOb) had higher body adiposity and exhibited sex-specific differences in glucose tolerance and insulin secretion. The male MatOb offspring developed the highest extent of glucose intolerance and lowest glucose-induced insulin secretion. In contrast, P21 female offspring of obese dams had unimpaired insulin secretion. Using SAX-HPLC, we found that male MatOb had a decrease in pancreatic heparan sulfate glycosaminoglycan, which is a macromolecule critical for islet health. Notably, 8-weeks-old offspring of obese dams continued to exhibit a similar pattern of sex-differences in glucose intolerance and decreased islet insulin secretion. Overall, our study suggests that maternal obesity induces sex-specific changes to pancreatic HSG in offspring and a lasting effect on offspring insulin secretion, leading to the sex-differences in glucose intolerance.

MicroRNA Let-7 targets AMPK and impairs hepatic lipid metabolism in offspring of maternal obese pregnancies

Nutritional status during gestation may lead to a phenomenon known as metabolic programming, which can be triggered by epigenetic mechanisms. The Let-7 family of microRNAs were one of the first to be discovered, and are closely related to metabolic processes. Bioinformatic analysis revealed that Prkaa2, the gene that encodes AMPK α2, is a predicted target of Let-7. Here we aimed to investigate whether Let-7 has a role in AMPKα2 levels in the NAFLD development in the offspring programmed by maternal obesity. Let-7 levels were upregulated in the liver of newborn mice from obese dams, while the levels of Prkaa2 were downregulated. Let-7 levels strongly correlated with serum glucose, insulin and NEFA, and in vitro treatment of AML12 with glucose and NEFA lead to higher Let-7 expression. Transfection of Let-7a mimic lead to downregulation of AMPKα2 levels, while the transfection with Let-7a inhibitor impaired both NEFA-mediated reduction of Prkaa2 levels and the fat accumulation driven by NEFA. The transfection of Let-7a inhibitor in ex-vivo liver slices from the offspring of obese dams restored phospho-AMPKα2 levels. In summary, Let-7a appears to regulate hepatic AMPKα2 protein levels and lead to the early hepatic metabolic disturbances in the offspring of obese dams.

The dual nature of obesity in metabolic programming: quantity versus quality of adipose tissue

The global prevalence of obesity has been rising at an alarming rate, accompanied by an increase in both childhood and maternal obesity. The concept of metabolic programming is highly topical, and in this context, describes a predisposition of offspring of obese mothers to the development of obesity independent of environmental factors. Research published in this issue of Clinical Science conducted by Litzenburger and colleagues (Clin. Sci. (Lond.) (2020) 134, 921-939) have identified sex-dependent differences in metabolic programming and identify putative signaling pathways involved in the differential phenotype of adipose tissue between males and females. Delineating the distinction between metabolically healthy and unhealthy obesity is a topic of emerging interest, and the precise nature of adipocytes are key to pathogenesis, independent of adipose tissue volume.

Molecular mechanisms governing offspring metabolic programming in rodent models of in utero stress

The results of different human epidemiological datasets provided the impetus to introduce the now commonly accepted theory coined as 'developmental programming', whereby the presence of a stressor during gestation predisposes the growing fetus to develop diseases, such as metabolic dysfunction in later postnatal life. However, in a clinical setting, human lifespan and inaccessibility to tissue for analysis are major limitations to study the molecular mechanisms governing developmental programming. Subsequently, studies using animal models have proved indispensable to the identification of key molecular pathways and epigenetic mechanisms that are dysregulated in metabolic organs of the fetus and adult programmed due to an adverse gestational environment. Rodents such as mice and rats are the most used experimental animals in the study of developmental programming. This review summarises the molecular pathways and epigenetic mechanisms influencing alterations in metabolic tissues of rodent offspring exposed to in utero stress and subsequently programmed for metabolic dysfunction. By comparing molecular mechanisms in a variety of rodent models of in utero stress, we hope to summarise common themes and pathways governing later metabolic dysfunction in the offspring whilst identifying reasons for incongruencies between models so to inform future work. With the continued use and refinement of such models of developmental programming, the scientific community may gain the knowledge required for the targeted treatment of metabolic diseases that have intrauterine origins.

Maternal resistance to diet-induced obesity partially protects newborn and post-weaning male mice offspring from metabolic disturbances

The rising rate of childhood overweight follows the increase in maternal obesity, since perinatal events impact offspring in a diversity of metabolic disorders. Despite many studies that have linked dietary consumption, overnutrition, or maternal obesity as the mediators of fetal metabolic programming, there are gaps regarding the knowledge about the contribution of different maternal phenotypes to the development of metabolic disturbances in offspring. This study aimed to investigate whether maternal high-fat diet (HFD) consumption without the development of the obese phenotype would protect offspring from metabolic disturbances. Female mice were fed standard chow diet or a HFD for 4 weeks before mating. HFD females were classified into obesity-resistant (OR) or obesity-prone (OP), according to weight gain. OP females presented with higher adiposity, fasting serum glucose and insulin, cholesterol and non-esterified fatty acid (NEFA). Newborn offspring from OP dams showed higher serum glucose and insulin and alteration in hepatic gene expression that may have contributed to the rise in hepatic fat content and decline of glycogen levels in the liver. Despite offspring from OR and OP females having showed similar growth after the day of delivery, offspring from OP females had higher caloric intake, fasting glucose, serum triglycerides and altered hepatic gene expression, as well as glucose and pyruvate intolerance and lower insulin sensitivity at d28 compared with offspring from OR females. Maternal pre-pregnancy serum glucose, insulin, and NEFA positively correlated with serum glucose and fat liver content and negatively correlated with hepatic glycogen in offspring. In conclusion, our results show that maternal resistance to diet-induced obesity partially protects offspring from early metabolic disturbances.

Neonatal administration of kaempferol does not alter satiety but increases somatic growth and reduces adiposity in offspring of high-fat diet dams

AIM

The aim of this study was to evaluate the effects of maternal exposure to a high-fat diet associated with neonatal administration of kaempferol on somatic growth, biochemical profile and feeding behavior in offspring.

MATERIALS AND METHODS

Wistar rats were distributed according to diet during pregnancy and lactation into Control (C; 3.4 kcal/g; 12% kcal/lipids) or High-fat (HFD; 4.6 kcal/g; 51% kcal/lipids) groups. In the offspring, vehicle (V) or kaempferol (K, 1 mg/kg) were administered from the 8th until the 21st postnatal day (PND). Maternal body weight (BW), caloric intake and adiposity were measured. In the offspring, somatic growth parameters were evaluated on the 7th, 14th, 21st, 25th and 30th PND, except for BW, which was measured from the 8th to the 21st and from the 25th to the 30th PND. Feeding behavior was assessed by food intake and behavioral satiety sequence (BSS) on the 30th PND. The biochemical profile and relative weight of adipose tissue of offspring were also measured.

KEY FINDINGS

Dams exposed to HFD showed no difference in body weight and caloric intake but exhibited increased adiposity. Neonatal administration of kaempferol increased body weight after weaning and somatic growth in the offspring of HFD dams. Neonatal kaempferol also reduced adiposity and serum creatinine levels in offspring. Neither maternal diet nor kaempferol altered offspring feeding behavior.

SIGNIFICANCE

Neonatal administration of kaempferol promotes increased somatic growth post-weaning, reduces adiposity, and does not alter feeding behavior in offspring from high-fat dams.

Perinatal exposure to maternal obesity: Lasting cardiometabolic impact on offspring

Evidence from epidemiological, clinical, and animal model studies clearly demonstrates that prenatal and lactational maternal obesity and high-fat diet consumption are associated with cardiometabolic morbidity in offspring. Fetal and offspring sex may be an important effect modifier. Adverse offspring cardiometabolic outcomes observed in the setting of maternal obesity include an increased risk for obesity, features of metabolic syndrome (hypertension, hyperglycemia and insulin resistance, hyperlipidemia, increased adiposity), and non-alcoholic fatty liver disease. This review article synthesizes human and animal data linking maternal obesity and high-fat diet consumption in pregnancy and lactation to adverse cardiometabolic outcomes in offspring. We review key mechanisms underlying skeletal muscle, adipose tissue, pancreatic, liver, and central brain reward programming in obesity-exposed offspring, and how such malprogramming contributes to offspring cardiometabolic morbidity.

Relationship of maternal high-fat diet during pregnancy and lactation to offspring health

A balanced maternal diet is essential for proper fetal development, and the consumption of a nutritionally inadequate diet during intrauterine development and early childhood is associated with a significantly increased risk of metabolic and brain disorders in offspring. The current literature indicates that maternal exposure to a high-fat diet exerts an irreversible influence on the general health of the offspring. This review of preclinical research examines the relationship between a maternal high-fat diet during pregnancy or lactation and metabolic changes, molecular alterations in the brain, and behavioral disorders in offspring. Animal models indicate that offspring exposed to a maternal high-fat diet during pregnancy and lactation manifest increased depressive-like and aggressive behaviors, reduced cognitive development, and symptoms of metabolic syndrome. Recently, epigenetic and molecular studies have shown that maternal nutrition during pregnancy and the suckling period modifies the development of neurotransmitter circuits and many other factors important to central nervous system development. This finding confirms the importance of a balanced maternal diet for the health of offspring.

Maternal high fat diet consumption reduces liver alpha7 nicotinic cholinergic receptor expression and impairs insulin signalling in the offspring

The activation of nicotinic acetylcholine receptor α7 subunit (α7nAChR) has been associated to anti-inflammatory response in macrophages. High-fat diet (HFD) consumption during pregnancy and lactation impairs the cholinergic anti-inflammatory pathway in liver and white adipose tissue of offspring. In order to evaluate the relationship between damage in the cholinergic anti-inflammatory pathway and insulin resistance (IR) development, the liver of offspring of obese dams was investigated. Additionally, the capacity of α7nAChR activation to reduce IR induced by saturated fatty acid was investigated in hepatoma cell line. Initially, female mice were subjected to either standard chow (SC) or HFD during pregnancy and lactation period. After weaning, only male offspring from HFD dams (HFD-O) and SC dams (SC-O) were fed with the SC diet. Hepatic α7nAChR expression was downregulated, and hepatic TNF-α, IL-1β, and pIKK level, but not pJNK, were elevated in the HFD-O compared to SC-O mice. Besides, hepatic expression of TNF-α in response to lipopolysaccharide (LPS) was higher in HFD-O than SC-O mice. Insulin-stimulated phosphorylation of the AKT was lower in HFD-O compared to SC-O. Additionally, insulin-stimulated phosphorylation of the AKT in KOα7^Alb-Cre mice fed HFD was lower than WT mice fed HFD. In hepatoma cell line, palmitate increased IL-6 and TNF-α expressions and pJNK level. These effects were accompanied by reduced capacity of insulin to stimulate AKT phosphorylation. PNU or nicotine reduced cytokine expression and JNK activation, but improved insulin resistance induced by palmitate. Our results suggest that maternal obesity impairs hepatic α7nAChR expression and AKT phosphorylation in the offspring. In vitro studies suggest that α7nAChR activation has potential to reduce deleterious effect of saturated fatty acids on insulin signalling.

Prenatal Choline Supplementation during High-Fat Feeding Improves Long-Term Blood Glucose Control in Male Mouse Offspring

Maternal obesity increases the risk of metabolic dysregulation in rodent offspring, especially when offspring are exposed to a high-fat (HF), obesogenic diet later in life. We previously demonstrated that maternal choline supplementation (MCS) in HF-fed mouse dams during gestation prevents fetal overgrowth and excess adiposity. In this study, we examined the long-term metabolic influence of MCS. C57BL/6J mice were fed a HF diet with or without choline supplementation prior to and during gestation. After weaning, their pups were exposed to either a HF or control diet for 6 weeks before measurements. Prenatal and post-weaning dietary treatments led to sexually dimorphic responses. In male offspring, while post-weaning HF led to impaired fasting glucose and worse glucose tolerance (p < 0.05), MCS in HF dams (HFCS) attenuated these changes. HFCS (versus maternal normal fat control) appeared to improve metabolic functioning of visceral adipose tissue during post-weaning HF feeding, preventing the elevation in leptin and increasing (p < 0.05) mRNA expression of insulin receptor substrate 1 (Irs1) that promotes peripheral insulin signaling in male offspring. In contrast, MCS had minimal effects on metabolic outcomes of female offspring. In conclusion, MCS during HF feeding in mice improves long-term blood glucose homeostasis in male offspring when they are faced with a postnatal obesogenic environment.

The effect of troxerutin on anxiety- and depressive-like behaviours in the offspring of high-fat diet fed dams

This study aimed at investigating the metabolic and behavioural effects of troxerutin treatment in the offspring of high fat diet (HFD) fed dams. Female Wistar rats (n = 40) received normal diet (ND) or HFD for 8 weeks prior to breeding. After mating, pregnant animals were assigned to four subgroups: ND, ND + Tro (troxerutin 150 mg/kg/day), HFD, and HFD + Tro. On the 21st day, male offspring were weaned and fed ND until 12 weeks old. Behavioural tests were performed on postnatal day (PND) 80 and 90. Compared to the controls, the HFD offspring showed more anxiety- and depressive-like behaviours, higher blood glucose, cholesterol, and cortisol levels. On the other hand, chronic troxerutin administration during gestation restored metabolic and behavioural changes to normal. In summary, troxerutin improved anxiety- and depressive-like behaviours, as well as metabolic status in the offspring of the HFD fed dams. More studies are needed to determine the underlying mechanisms.

High-fat diet affects pregestational adiposity and glucose tolerance perturbing gestational placental macronutrient transporters culminating in an obese offspring in wild-type and glucose transporter isoform 3 heterozygous null mice

We examined the effect of a high-fat diet (HFD) vs. control diet (CD) upon pregestational and gestational wild-type (wt) and glucose transporter (glut)3 heterozygous (glut3^+/-) female mice and observed an increase in pregestational body weights, white adiposity (wt > glut3^+/-), circulating cholesterol, and high-density lipoproteins, with glucose intolerance in both genotypes. The HFD-exposed offspring displayed reduced birth weight with catch up to CD-fed in wt vs. an increased birth weight persisting as such at weaning by day 21 in glut3^+/- mice. To decipher the mechanism behind this genotype-specific difference in the HFD offspring's phenotype, we first examined placental macronutrient transporters and noted HFD-induced increase in CD36 in wt with no change in other FATPs, sodium-coupled neutral amino acid transporters and system L amino acid transporter in both genotypes. In contrast, while placental Glut1 increased in both the genotypes, only Glut3 increased in the glut3^+/- genotype in response to HFD. Hence, we next assessed glut3^+/- embryonic (ES) cells under differing stressors of low glucose, hypoxia and inhibition of oxidative phosphorylation. Reduced Glut3-mediated glucose uptake in glut3^+/- vs. wt ES cells culminated in deficient growth. We conclude that maternal HFD affects the in utero growth potential of the offspring by altering placental CD36 and Glut1 concentrations. In contrast, a differential effect on placental Glut3 concentrations between glut3^+/- and wt genotypes is evident, with an increase occurring in the glut3^+/- genotype alone. Deficient Glut3 in ES cells interferes with glucose uptake, cell survival and growth being further exaggerated with low glucose, hypoxia and inhibition of oxidative phosphorylation.

Maternal diet-induced obesity during suckling period programs offspring obese phenotype and hypothalamic leptin/insulin resistance

During the early post-natal period, offspring are vulnerable to environmental insults, such as nutritional and hormonal changes, which increase risk to develop metabolic diseases later in life. Our aim was to understand whether maternal obesity during lactation programs offspring to metabolic syndrome and obese phenotype, in addition we aimed to assess the peripheral glucose metabolism and hypothalamic leptin/insulin signaling pathways. At delivery, female Wistar rats were randomly divided in two groups: Control group (CO), mothers fed a standard rodent chow (Nuvilab); and Diet-induced obesity group (DIO), mothers who had free access to a diet performed with 33% ground standard rodent chow, 33% sweetened condensed milk (Nestlé), 7% sucrose and 27% water. Maternal treatment was performed throughout suckling period. All offspring received standard rodent chow from weaning until 91-day-old. DIO dams presented increased total body fat and insulin resistance. Consequently, the breast milk from obese dams had altered composition. At 91-day-old, DIO offspring had overweight, hyperphagia and higher adiposity. Furthermore, DIO animals had hyperinsulinemia and insulin resistance, they also showed pancreatic islet hypertrophy and increased pancreatic β-cell proliferation. Finally, DIO offspring showed low ObRb, JAK2, STAT-3, IRβ, PI3K and Akt levels, suggesting leptin and insulin hypothalamic resistance, associated with increased of hypothalamic NPY level and decreased of POMC. Maternal obesity during lactation malprograms rat offspring to develop obesity that is associated with impairment of melanocortin system. Indeed, rat offspring displayed glucose dyshomeostasis and both peripheral and central insulin resistance.

The effect of Guarana (Paullinia cupana) on metabolic and inflammatory parameters in adult male mice programmed by maternal obesity

PURPOSE

Maternal obesity can program the offspring, increasing the risk of overweight and obesity in adult life. Guarana (Paullinia cupana) is a Brazilian plant that has weight-reducing effects. Thus, this study aimed to evaluate the effects of Guarana on metabolic and inflammatory parameters in mice programmed by maternal obesity.

METHODS

Swiss female mice were divided into two groups: control and high fat (HF), who received a standard diet or a high-fat diet (HFD), respectively, for 8 weeks prior to mating, gestation, and lactation. After post-natal day (PN) 21, the offspring of the HF group were subdivided into three groups: HF without treatment; HF early treatment, offspring treated with Guarana (1 g/kg bodyweight) in PN25-PN30; HF late treatment, offspring treated with Guarana (1 g/kg bodyweight) in PN65-PN75. Basal energy expenditure, the lipid profile and fasting glucose levels were determined. Body composition was evaluated by dissecting adipose tissue depots. Gene expression was analyzed using real-time PCR.

RESULTS

During mating, the weight of HF females increased; after lactation, their adipose tissue depots and fasting glycemic levels also increased. The offspring of the HF group showed an increased body weight at PN21. At PN80, in the mice treated with Guarana (with both treatments), VO₂ and energy expenditure increased, adipose tissue depots decreased, and the expression of leptin, IL-6, TNF-α, and MCP-1 decreased compared with that in the HF group.

CONCLUSIONS

Guarana treatment at both stages of life reversed some of the alterations developed by the offspring of HF animals in adult life.

The nutrition-gut microbiome-physiology axis and allergic diseases

Dietary and bacterial metabolites influence immune responses. This raises the question whether the increased incidence of allergies, asthma, some autoimmune diseases, cardiovascular disease, and others might relate to intake of unhealthy foods, and the decreased intake of dietary fiber. In recent years, new knowledge on the molecular mechanisms underpinning a 'diet-gut microbiota-physiology axis' has emerged to substantiate this idea. Fiber is fermented to short chain fatty acids (SCFAs), particularly acetate, butyrate, and propionate. These metabolites bind 'metabolite-sensing' G-protein-coupled receptors such as GPR43, GPR41, and GPR109A. These receptors play fundamental roles in the promotion of gut homeostasis and the regulation of inflammatory responses. For instance, these receptors and their metabolites influence Treg biology, epithelial integrity, gut homeostasis, DC biology, and IgA antibody responses. The SCFAs also influence gene transcription in many cells and tissues, through their inhibition of histone deacetylase expression or function. Contained in this mix is the gut microbiome, as commensal bacteria in the gut have the necessary enzymes to digest dietary fiber to SCFAs, and dysbiosis in the gut may affect the production of SCFAs and their distribution to tissues throughout the body. SCFAs can epigenetically modify DNA, and so may be one mechanism to account for diseases with a 'developmental origin', whereby in utero or post-natal exposure to environmental factors (such as nutrition of the mother) may account for disease later in life. If the nutrition-gut microbiome-physiology axis does underpin at least some of the Western lifestyle influence on asthma and allergies, then there is tremendous scope to correct this with healthy foodstuffs, probiotics, and prebiotics.

Paternal high-fat diet enhances offspring whole-body insulin sensitivity and skeletal muscle insulin signaling early in life

Evidence suggests that paternal diet can predispose offspring to metabolic dysfunction. Despite this knowledge, little is known regarding the effects of paternal high-fat feeding on offspring insulin sensitivity. The purpose of this study was to investigate for the first time the effects of paternal high-fat feeding on whole-body and skeletal muscle insulin action in young and adult offspring. At 4 weeks of age, founder C57BL6/N males (F0) were fed a high-fat diet or control diet for 12 weeks and then bred with females on a control diet. Offspring (F1) were euthanized at 6 weeks, 6 months, or 12 months and insulin-stimulated insulin signaling was measured ex vivo in isolated soleus muscle. At 6 weeks of age, paternal high fat offspring (HFO) had enhanced whole-body insulin sensitivity (35%, P < 0.05), as well as, increased insulin-stimulated skeletal muscle phosphorylation of Akt threonine 308 (70%, P < 0.05) and AS160 threonine 642 (80%, P < 0.05) compared to paternal control fed offspring (CFO), despite both offspring groups consuming standard chow. At 6 months of age, HFO had increased percent body fat compared to CFO (74%, P < 0.005) and whole-body and skeletal muscle insulin signaling normalized to CFO. Body fat was inversely related with insulin signaling in HFO, but not CFO. These findings suggest that paternal high-fat feeding contributes to enhanced whole-body and skeletal muscle insulin sensitivity in HFO early in life; however, these benefits are lost by early adulthood, potentially due to premature increases in body fat.

Intrauterine growth restriction combined with a maternal high-fat diet increased adiposity and serum corticosterone levels in adult rat offspring

Intrauterine growth restriction (IUGR) and fetal exposure to a maternal high-fat diet (HFD) independently increase the risk of developing obesity in adulthood. Excess glucocorticoids increase obesity. We hypothesized that surgically induced IUGR combined with an HFD would increase adiposity and glucocorticoids more than in non-IUGR offspring combined with the same HFD, findings that would persist despite weaning to a regular diet. Non-IUGR (N) and IUGR (I) rat offspring from dams fed either regular rat chow (R) or an HFD (H) were weaned to either a regular rat chow or an HFD. For non-IUGR and IUGR rats, this study design resulted in three diet groups: offspring from dams fed a regular diet and weaned to a regular diet (NRR and IRR), offspring rats from dams fed an HFD and weaned to a regular diet (NHR and IHR) and offspring from dams fed an HFD and weaned to an HFD (NHH and IHH). Magnetic resonance imaging or fasting visceral and subcutaneous adipose tissue collection occurred at postnatal day 60. IHH male rats had greater adiposity than NHH males, findings that were only partly normalized by weaning to a regular chow. IHH male rats had a 10-fold increase in serum corticosterone levels. IHH female rats had increased adiposity and serum triglycerides. We conclude that IUGR combined with an HFD throughout life increased adiposity, glucocorticoids and triglycerides in a sex-specific manner. Our data suggest that one mechanism through which the perinatal environment programs increased adiposity in IHH male rats may be via increased systemic glucocorticoids.

Helianthus tuberosus (Jerusalem artichoke) tubers improve glucose tolerance and hepatic lipid profile in rats fed a high-fat diet

OBJECTIVES

To analyze the effects of feeding Helianthus tuberosus (HT) tubers on glucose tolerance and lipid profile in rats fed a high-fat diet (HFD).

METHODS

A normal HFD or HFD including 10 w/w% HT tubers (HFD + HT) was fed to F334/Jcl rats. After 10 weeks, organ weights, glucose tolerance, and lipid profile were analyzed.

RESULTS

The body weight, liver weight, and epidermal fat content in the HFD group were higher than those of the normal group, and similar to those of the HFD + HT group. The oral glucose tolerance test at 10 weeks revealed that the blood glucose level 30 min after beginning the test in the HFD + HT group was significantly lower than that in the HFD group. Liver triglyceride and total cholesterol levels in the HFD + HT group were significantly lower than those in the HFD group. Fecal triglyceride and total cholesterol levels in the HFD + HT group were higher than those in the HFD group. Histological analyses revealed that fat and glycogen accumulation increased in the HFD group, but decreased in the HFD + HT group.

CONCLUSIONS

These results indicate that HT tubers have anti-fatty liver effects based on improvements in glucose tolerance and the hepatic lipid profile.

Chronic maternal inflammation or high-fat-feeding programs offspring obesity in a sex-dependent manner

BACKGROUND/OBJECTIVES

The current world-wide obesity epidemic partially results from a vicious circle whereby maternal obesity during pregnancy predisposes the offspring for accelerated weight gain and development of metabolic syndrome. Here we investigate whether low-grade inflammation, characteristic of the obese state, provides a causal role for this disastrous fetal programming in mice.

METHODS

We exposed pregnant and lactating C57BL/6JBom female mice to either high-fat diet (HFD), or continuous infusion of lipopolysaccharide (LPS), a potent trigger of innate immunity, and studied offspring phenotypes.

RESULTS

Both maternal LPS or HFD treatments rendered the offspring hyperphagic and inept of coping with a HFD challenge during adulthood, increasing their adiposity and weight gain. The metabolic effects were more pronounced in female offspring, while exposed male offspring mounted a larger inflammatory response to HFD at adulthood.

CONCLUSIONS

This supports our hypothesis and highlights the programming potential of inflammation in obese pregnancies.

Lipid overload during gestation and lactation can independently alter lipid homeostasis in offspring and promote metabolic impairment after new challenge to high-fat diet

Background

Nutritional status in early life is critically involved in the metabolic phenotype of offspring. However the changes triggered by maternal consumption of high-fat diet (HFD) in pre- or postnatal period should be better understood. Here we evaluated whether maternal HFD consumption during gestation and lactation could differently affect liver miR-122 and miR-370 expression leading to metabolic damages observed in offspring. Moreover, we investigate whether early overnutrition program offspring to more harmful response to HFD in later life.

Methods

Female mice were fed either a standard chow (SC) diet or a HFD three weeks before and during mating, gestation and/or lactation. Offspring were evaluated on the delivery day (d0), in a cross-fostering model at day 28 (d28) and in adult life, after a re-challenge with a HFD (d82).

Results

In vitro analysis using liver cell line showed that palmitate could induced decrease in miR-122 and increase in miR-370 expression. Newborn pups (d0) from obese dams showed a decrease in lipid oxidation markers (Cpt1a and Acadvl), an increase in triacylglycerol synthesis markers (Agpat and Gpam), as well as lower miR-122 and higher miR-370 hepatic content that was inversely correlated to maternal serum NEFA and TAG. Pups fostered to SC dams presented an increase in body weight and Agpat/Gpam expression at d28 compared to pups fostered to HFD dams and an inverse correlation was observed between miR-122 hepatic expression and offspring serum TAG. In adult life (d82), the reintroduction of HFD resulted in higher body weight gain and hepatic lipid content. These effects were accompanied by impairment in lipid and glucose metabolism, demonstrated by reduced Cpt1a/Acadvl and increased Agpat/Gpam expression, lower glucose tolerance and insulin sensitivity.

Conclusion

Our data suggest that both gestational and lactation overnutrition results in metabolic changes that can permanently alter lipid homeostasis in offspring. The presence of fatty acids in maternal blood and milk seem to be responsible for modulating the expression of miR-122 and miR-370, which are involved in liver metabolism. These alterations significantly increase susceptibility to obesity and ectopic lipid accumulation and lead to a more harmful response to HFD in offspring.

Electronic supplementary material

The online version of this article (doi:10.1186/s12986-017-0168-4) contains supplementary material, which is available to authorized users.

Lipid overload during gestation and lactation can independently alter lipid homeostasis in offspring and promote metabolic impairment after new challenge to high-fat diet

BACKGROUND

Nutritional status in early life is critically involved in the metabolic phenotype of offspring. However the changes triggered by maternal consumption of high-fat diet (HFD) in pre- or postnatal period should be better understood. Here we evaluated whether maternal HFD consumption during gestation and lactation could differently affect liver miR-122 and miR-370 expression leading to metabolic damages observed in offspring. Moreover, we investigate whether early overnutrition program offspring to more harmful response to HFD in later life.

METHODS

Female mice were fed either a standard chow (SC) diet or a HFD three weeks before and during mating, gestation and/or lactation. Offspring were evaluated on the delivery day (d0), in a cross-fostering model at day 28 (d28) and in adult life, after a re-challenge with a HFD (d82).

RESULTS

In vitro analysis using liver cell line showed that palmitate could induced decrease in miR-122 and increase in miR-370 expression. Newborn pups (d0) from obese dams showed a decrease in lipid oxidation markers (Cpt1a and Acadvl), an increase in triacylglycerol synthesis markers (Agpat and Gpam), as well as lower miR-122 and higher miR-370 hepatic content that was inversely correlated to maternal serum NEFA and TAG. Pups fostered to SC dams presented an increase in body weight and Agpat/Gpam expression at d28 compared to pups fostered to HFD dams and an inverse correlation was observed between miR-122 hepatic expression and offspring serum TAG. In adult life (d82), the reintroduction of HFD resulted in higher body weight gain and hepatic lipid content. These effects were accompanied by impairment in lipid and glucose metabolism, demonstrated by reduced Cpt1a/Acadvl and increased Agpat/Gpam expression, lower glucose tolerance and insulin sensitivity.

CONCLUSION

Our data suggest that both gestational and lactation overnutrition results in metabolic changes that can permanently alter lipid homeostasis in offspring. The presence of fatty acids in maternal blood and milk seem to be responsible for modulating the expression of miR-122 and miR-370, which are involved in liver metabolism. These alterations significantly increase susceptibility to obesity and ectopic lipid accumulation and lead to a more harmful response to HFD in offspring.