Effect of maternal protein restriction during pregnancy and postweaning high-fat feeding on diet-induced thermogenesis in adult mouse offspring

Maternal Brown Rice Diet during Pregnancy Promotes Adipose Tissue Browning in Offspring via Reprogramming PKA Signaling and DNA Methylation

SCOPE

Brown rice, the most consumed food worldwide, has been shown to possess beneficial effects on the prevention of metabolic diseases. However, the way in which maternal brown rice diet improves metabolism in offspring and the regulatory mechanisms remains unclear. The study explores the epigenetic regulation of offspring energy metabolic homeostasis by maternal brown rice diet during pregnancy.

METHODS AND RESULTS

Female mice are fed brown rice during pregnancy, and then body phenotypes, the histopathological analysis, and adipose tissues biochemistry assay of offspring mice are detected. It is found that maternal brown rice diet significantly reduces body weight and fat mass, increases energy expenditure and heat production in offspring. Maternal brown rice diet increases uncoupling protein 1 (UCP1) protein level and upregulates the mRNA expression of thermogenic genes in adipose tissues. Mechanistically, protein kinase A (PKA) signaling is likely responsible in the induced thermogenic program in offspring adipocytes, and the progeny adipocytes browning program is altered due to decreased level of DNA methyltransferase 1 protein and hypomethylation of the transcriptional coregulator positive regulatory domain containing 16 (PRDM16).

CONCLUSIONS

These findings demonstrate that maternal brown rice during pregnancy improves offspring mice metabolic homeostasis via promoting adipose browning, and its mechanisms may be mediated by DNA methylation reprogramming.

High-fat diet during pregnancy lowers fetal weight and has a long-lasting adverse effect on brown adipose tissue in the offspring

Maternal obesity and malnutrition during gestation and lactation have been recognized to increase the risk of obesity and metabolic disorders in the offspring across their lifespan. However, the gestational period during which malnutrition exerts a decisive effect is unclear. Brown adipose tissue (BAT) plays a critical role in energy metabolism owing to its high efficiency in oxidizing glucose and fatty acids. This study aimed to determine the impact of maternal high-fat diet (HFD) consumption only during pregnancy on BAT and energy metabolism in offspring mice. Dams were fed an HFD or a normal chow diet from embryonic day 2.5. HFD consumption during pregnancy induced glucose intolerance and hypertension in dams. In the offspring of HFD-fed dams, maternal HFD lowered fetal weight without affecting placental weight, whereas HFD consumption after birth exacerbated oxygen consumption and cold-induced thermogenesis at 12 months of age, accompanied by increased lipid droplet size in BAT. These data demonstrate that HFD consumption only during pregnancy exerts a long-lasting effect on BAT. Collectively, these findings indicate the importance of nutrition during pregnancy with respect to the energy metabolism of the offspring, and pregnant women should thus ensure proper nutrition during pregnancy to ensure normal energy metabolism in the offspring.

Cardiometabolic Effects of Postnatal High-Fat Diet Consumption in Offspring Exposed to Maternal Protein Restriction In Utero

In recent decades, the high incidence of infectious and parasitic diseases has been replaced by a high prevalence of chronic and degenerative diseases. Concomitantly, there have been profound changes in the behavior and eating habits of families around the world, characterizing a “nutritional transition” phenomenon, which refers to a shift in diet in response to modernization, urbanization, or economic development from undernutrition to the excessive consumption of hypercaloric and ultra-processed foods. Protein malnutrition that was a health problem in the first half of the 20th century has now been replaced by high-fat diets, especially diets high in saturated fat, predisposing consumers to overweight and obesity. This panorama points us to the alarming coexistence of both malnutrition and obesity in the same population. In this way, individuals whose mothers were undernourished early in pregnancy and then exposed to postnatal hyperlipidic nutrition have increased risk factors for developing metabolic dysfunction and cardiovascular diseases in adulthood. Thus, our major aim was to review the cardiometabolic effects resulting from postnatal hyperlipidic diets in protein-restricted subjects, as well as to examine the epigenetic repercussions occasioned by the nutritional transition.

Effects of Low Protein-High Carbohydrate Diet during Early and Late Pregnancy on Respiratory Quotient and Visceral Adiposity

Background

Low Protein-High Carbohydrate (LPHC) diet during pregnancy is considered a nutritional and health problem related to the development of maternal metabolic alterations, such as fatty liver and obesity in the perinatal and postnatal period. It is known that increase in visceral adiposity tissue (VAT) modulates maternal metabolic rate, with the respiratory quotient (RQ) being a parameter related to that variable; however, it is unknown whether LPHC intake during pregnancy affects the VAT and the RQ. In this study, we examine if consumption of LPHC during pregnancy modifies the VAT and RQ in early and late periods of pregnancy.

Methods

This is a longitudinal and cross-sectional study with Wistar rats during gestation (G) (3, 8, 15, and 20) and nonpregnant rats. Rats were fed with a control diet with 63/18% carbohydrate/protein and an experimental diet with 79/6% carbohydrate/protein. We studied water and food consumption and metabolic parameters such as RQ and energy expenditure (EE), calculated by indirect calorimetry. In the cross-sectional study, we determined visceral fat, as well as the concentration of free fatty acids, insulin, glucose, and lipid profile in serum.

Results

Nonpregnant rats with LPHC intake decreased significantly in VAT (86%) and the RQ (18%); in pregnant rats in early (8G) and late pregnancy (15G) in LPHC diet, both parameters (VAT and RQ) (25%-92%) increased during light time. When comparing time points during pregnancy in the control and LPHC groups, the RQ increased in 15G during daytime compared to 8G during the night period (17 and 5%, respectively). In late pregnancy, LPHC intake and triacylglyceride levels increased and cholesterol and glucose decreased (45 and 26%, respectively), in comparison to nonpregnant rats.

Conclusions

LPHC intake in nonpregnant rats decreases the RQ and VAT. Interestingly, the opposite occurs in early pregnancy: the RQ and VAT increased, and this correlates with free fatty acid (FFA) levels. The increase in RQ and VAT during light time in early pregnancy increased mobilization of carbohydrate and protein metabolism. These results suggest that LPHC intake during pregnancy increases the glucose metabolism as a compensatory mechanism for energy needs in the fetus and the mother in early pregnancy.

Maternal Protein Restriction and Post-Weaning High-Fat Feeding Alter Plasma Amino Acid Profiles and Hepatic Gene Expression in Mice Offspring

Maternal undernutrition during pregnancy is closely associated with epigenetic changes in the child, and it affects the development of obesity throughout the child’s life. Here, we investigate the effect of fetal low protein exposure and post-weaning high-fat consumption on plasma amino acid profiles and hepatic gene expression. Mother C57BL/6J mice were fed a 20% (CN) or 9% (LP) casein diet during pregnancy. After birth, the male offspring of both these groups were fed a high-fat diet (HF) from 6 to 32 weeks. At 32 weeks, the final body weight between the two groups remained unchanged, but the LP-HF group showed markedly higher white fat weight and plasma leptin levels. The LP-HF group exhibited a significant increase in the concentrations of isoleucine, leucine, histidine, phenylalanine, serine, and tyrosine. However, no differences were observed in the lipid content in the liver. According to the hepatic gene expression analysis, the LP-HF group significantly upregulated genes involved in the chromatin modification/organization pathways. Thus, maternal low protein and a post-weaning high-fat environment contributed to severe obesity states and changes in gene expression related to hepatic chromatin modification in offspring. These findings provide novel insights for the prevention of lifestyle-related diseases at the early life stage.

Maternal high fructose diet exacerbates white adipose tissue thermogenic process in offspring upon exposure to cold temperature

AIM

An adverse endogenous environment during early life predisposes to metabolic disorder development. We previously reported adverse metabolic and adipose tissue effects in adult male rats born to dams fed with a fructose-rich diet (FRD). The aim of this work was to determine the effect of a FRD consumed by the pregnant mother on the white adipose tissue (WAT) browning capacity of male offspring at adulthood.

MAIN METHODS

Adult SD male offspring from control (C) and FRD-fed mothers were exposed during one week to a cold stimulus. WAT browning capacity was studied through in vivo and in vitro approaches.

KEY FINDINGS

After cold exposure, WAT browning was higher in fructose-programmed animals as evidenced by an increase in ucp-1 gene expression, protein levels, and higher UCP-1 positive foci. Moreover, pgc1-α gene expression was increased. In vitro studies showed a lower adipogenic capacity in cells of prenatally fructose-exposed animals differentiated with a white differentiation cocktail, while a higher ucp-1 expression was noted when their cells were treated with a pro-beige differentiation cocktail.

SIGNIFICANCE

For the first time we demonstrate that pre-natal fructose exposure predisposes programmed male rats to a higher WAT browning-induced response, under stimulated conditions, despite an apparent lower basal thermogenic capacity. These results should be considered in future studies to generate new therapeutic approaches to deal with adverse programming malnutrition effects.

Long-Term Effects of Maternal Low-Protein Diet and Post-weaning High-Fat Feeding on Glucose Metabolism and Hypothalamic POMC Promoter Methylation in Offspring Mice

Substantial evidence indicated that maternal malnutrition could increase the susceptibility to obesity, insulin resistance, and type 2 diabetes in adulthood. It is increasingly apparent that the brain, especially the hypothalamus, plays a critical role in glucose homeostasis. However, little information is known about the mechanisms linking maternal protein restriction combined with post-weaning high-fat (HF) feeding with altered expression of brain neurotransmitters, and investigations into the epigenetic modifications of hypothalamus in offspring have not been fully elucidated. Our objective was to explore the effects of maternal protein restriction combined with post-weaning HF feeding on glucose metabolism and hypothalamic POMC methylation in male offspring mice. C57/BL6 mice were fed on either low-protein (LP) or normal chow (NC) diet throughout gestation and lactation. Then, the male offspring were randomly weaned to either NC or high-fat (HF) diet until 32 weeks of age. Gene expressions and DNA methylation of hypothalamic proopiomelanocortin (POMC) and melanocortin receptor 4 (MC4R) were determined in male offspring. The results showed that birth weights and body weights at weaning were both significantly lower in male offspring mice of the dams fed with a LP diet. Maternal protein restriction combined with post-weaning high-fat feeding, predisposes higher body weight, persistent glucose intolerance (from weaning to 32 weeks of age), hyperinsulinemia, and hyperleptinemia in male offspring mice. POMC and MC4R expressions were significantly increased in offspring mice fed with maternal LP and postnatal high-fat diet (P < 0.05). Furthermore, maternal protein restriction combined with post-weaning high-fat feeding induced hypomethylation of POMC promoter in the hypothalamus (P < 0.05) and POMC-specific methylation (%) was negatively correlated with the glucose response to a glucose load in male offspring mice (r = -0.42, P = 0.039). In conclusion, maternal LP diet combined with post-weaning high-fat feeding predisposed the male offspring to impaired glucose metabolism and hypothalamic POMC hypomethylation. These findings can advance our thinking about hypothalamic POMC gene methylation between maternal LP diet combined with post-weaning high-fat feeding and metabolic health in offspring.

Maternal Protein Restriction Altered Insulin Resistance and Inflammation-Associated Gene Expression in Adipose Tissue of Young Adult Mouse Offspring in Response to a High-Fat Diet

Maternal protein restriction is associated with increased risk of insulin resistance and inflammation in adulthood offspring. Here, we investigated whether maternal protein restriction could alter the risk of metabolic syndrome in postweaning high-fat (HF)-diet-challenged offspring, with focus on epididymal adipose tissue gene expression profile. Female ICR mice were fed a control (C) or a low-protein (LP) diet for two weeks before mating and throughout gestation and lactation, and their male offspring were fed an HF diet for 22 weeks (C/HF and LP/HF groups). A subset of offspring of control dams was fed a low-fat control diet (C/C group). In response to postweaning HF diet, serum insulin level and the homeostasis model assessment of insulin resistance (HOMA-IR) were increased in control offspring. Maternal LP diet decreased HOMA-IR and adipose tissue inflammation, and increased serum adiponectin level in the HF-diet-challenged offspring. Accordingly, functional analysis revealed that differentially expressed genes (DEGs) enriched in cytokine production were downregulated in the LP/HF group compared to the C/HF group. We also observed the several annotated gene ontology terms associated with innate immunity and phagocytosis in down-regulated DEGs between LP/HF and C/C groups. In conclusion, maternal protein restriction alleviated insulin resistance and inflammation in young offspring mice fed a HF diet but may impair development of immune system in offspring.

Programming mediated by fatty acids affects uncoupling protein 1 (UCP-1) in brown adipose tissue

Brown adipose tissue (BAT) has recently been given more attention for the part it plays in obesity. BAT can generate great amounts of heat through thermogenesis by the activation of uncoupling protein 1 (UCP-1), which can be regulated by many environmental factors such as diet. Moreover, the build-up of BAT relates to maternal nutritional changes during pregnancy and lactation. However, at present, there is a limited number of studies looking at maternal nutrition and BAT development, and it seems that the research trend in this field has been considerably declining since the 1980s. There is much to discover yet about the role of different fatty acids on the development of BAT and the activation of UCP-1 during the fetal and the postnatal periods of life. A better understanding of the impact of nutritional intervention on the epigenetic regulation of BAT could lead to new preventive care for metabolic diseases such as obesity. It is important to know in which circumstances lipids could programme BAT during pregnancy and lactation. The modification of maternal dietary fatty acids, amount and composition, during pregnancy and lactation might be a promising strategy for the prevention of obesity in the offspring and future generations.

The Divergent Effect of Maternal Protein Restriction during Pregnancy and Postweaning High-Fat Diet Feeding on Blood Pressure and Adiposity in Adult Mouse Offspring

Obesity is a growing health crisis of pandemic proportions. Numerous animal and human studies have confirmed that obesity and related metabolic abnormalities, such as insulin resistance and cardiovascular disease, may be programmed during development by adverse maternal nutrition. We previously documented that offspring of female mice who were protein-restricted during pregnancy alone had no alterations to their body weights, but did display a considerable reduction in food intake, a finding which was linked to reduced expression levels of appetite regulatory genes in the hypothalamus. Whether such observations were accompanied by changes in metabolic and phenotypic parameters remained to be determined. Female pregnant MF-1 mice were fed, exclusively during the pregnancy period, a normal protein diet containing 18% casein (C) or an isocaloric protein-restricted diet containing 9% casein (PR). From birth, the lactating dams were fed a normal protein diet. At weaning, offspring were fed either the standard chow which contain 7% kcal fat (C) or high-fat diet (HF, 45% kcal fat). This yielded 4 experimental groups denoted by maternal diet/offspring diet: C/C, C/HF, PR/C, PR/HF. Our results showed that offspring adiposity was significantly increased in HF-fed offspring, and was not affected by the 50% reduction in protein content of the maternal diet fed during pregnancy. Similarly, blood glucose levels were higher in HF-fed offspring, regardless of protein content of the maternal diet. Systolic blood pressure, on the other hand, was significantly increased in both male and female offspring of dams fed the PR diet, and this was exacerbated by a postweaning HF diet. Our results show that maternal protein restriction leads to elevations in systolic blood pressure, which is exacerbated by a postweaning HF-diet. Our present findings suggest that, while changes in offspring adiposity brought about by exposure to maternal protein restriction during pregnancy may be restored by adequate maternal protein content during lactation, the same may not be true for systolic blood pressure, which was similarly impaired, regardless of the timing of maternal low-protein exposure.

[Effect of metformin on insulin resistance during catch-up growth in mice with fetal growth restriction]

OBJECTIVE

To study the efficacy of metformin intervention on insulin resistance during catch-up growth in mice with fetal growth restriction (FGR).

METHODS

Mouse models of FGR were established by low protein diet feeding of the pregnant mice. Both the newborn female mice with FGR and normal control (NC) mice were randomized for feeding with a standard diet (SF) or a high-fat diet (HF) after weaning and treatment with gavage of either metformin or normal saline. The mice were examined for vaginal opening time and the estrous cycle at the age of 8 weeks. At the age of 12 weeks, 6 mice in anestrus from each group were fasted for 12 h for measurement of body weight, height, poundera index (PI), fasting blood glucose (FBG), fasting insulin (Fins), follicle stimulating hormone (FSH) and anti-Mullerian hormone (AMH), and the HOMA-IR was calculated. The reproductive capacity of female mice was assessed by mixing them with male mice at the ratio of 2:1. The 3 × 2 factorial analysis was conducted to determine the interactions between FGR, high-fat feeding and metformin.

RESULTS

Factorial analysis showed that FGR and high-fat feeding had significant effects on the PI index, Fins, HOMA-IR, vaginal opening time, and AMH (P<0.05). Metformin significantly affected the factors related to high-fat feeding including weight, PI, FPG, Fins, HOMA-IR and estrous cycle (P<0.05) and the factors related to FGR with the exception of height and FSH (P<0.05). FGR significantly affected the factors tested except for body weight (P<0.05); high-fat feeding affected all the factors but the FSH (P<0.05); metformin affected all the factors but the height and FSH (P<0.05). In the female mice treated with saline, the pregnancy rates differed significantly between FGR mice with high-fat feeding and control mice with standard feeding, and between FGR mice with standard feeding and high-fat feeding (P<0.05).

CONCLUSION

FGR mice can present with delayed puberty with rare ovulation and adulthood insulin resistance, and high-fat feeding after birth can promote the catch-up growth of FGR mice. Metformin intervention is effective for improving insulin resistance and reproductive-endocrine disorders in FGR mice during catch-up growth.

Age-Dependent Control of Energy Homeostasis by Brown Adipose Tissue in Progeny Subjected to Maternal Diet-Induced Fetal Programming

Epidemiological and animal studies show that deleterious maternal environments predispose aging offspring to metabolic disorders and type 2 diabetes. Young progenies in a rat model of maternal low-protein (LP) diet are normoglycemic despite collapsed insulin secretion. However, without further worsening of the insulin secretion defect, glucose homeostasis deteriorates in aging LP descendants. Here we report that normoglycemic and insulinopenic 3-month-old LP progeny shows increased body temperature and energy dissipation in association with enhanced brown adipose tissue (BAT) activity. In addition, it is protected against a cold challenge and high-fat diet (HFD)-induced obesity with associated insulin resistance and hyperglycemia. Surgical BAT ablation in 3-month-old LP offspring normalizes body temperature and causes postprandial hyperglycemia. At 10 months, BAT activity declines in LP progeny with the appearance of reduced protection to HFD-induced obesity; at 18 months, LP progeny displays a BAT activity comparable to control offspring and insulin resistance and hyperglycemia occur. Together our findings identify BAT as a decisive physiological determinant of the onset of metabolic dysregulation in offspring predisposed to altered β-cell function and hyperglycemia and place it as a critical regulator of fetal programming of adult metabolic disease.

The programming effects of nutrition-induced catch-up growth on gut microbiota and metabolic diseases in adult mice

Substantial evidence indicated that catch‐up growth could increase the susceptibility to obesity, insulin resistance, and type 2 diabetes mellitus in adulthood. However, investigations into the “programming” effects of catch‐up growth on gut microbiota in the offspring are limited. C57/BL6 mice were fed on either low protein (LP) or normal chow (NC) diet throughout gestation and lactation. Then, the offspring were randomly weaned to either NC or high fat (HF) diet until 32 weeks of age, generating four experimental groups: NC‐NC, NC‐HF, LP‐NC, and LP‐HF. Metabolic parameters and gut microbiota were examined in the offspring. It showed that the NC‐HF and LP‐HF offspring displayed higher body weight (P < 0.05), impaired glucose tolerance (P < 0.001), and elevated serum lipids (P < 0.05) at 32 weeks of age. Both the operational taxonomic units (OTUs) and the Shannon indexes (P < 0.05) showed significantly lower microbial diversity in NC‐HF and LP‐HF offspring. There were significant variations in the compositions of gut microbiota in the NC‐HF and LP‐HF offspring, compared with NC‐NC offspring (P < 0.05). Furthermore, it indicated Lactobacillus percentage was negatively associated with blood glucose concentrations of intraperitoneal glucose tolerance test (r = −0.886, P = 0.019). In conclusion, catch‐up growth predisposes the offspring to gut microbiota perturbation, obesity, impaired glucose tolerance, insulin resistance, and dyslipidemia. Our study is novel in showing the “programming” effects of nutrition‐induced catch‐up growth on gut microbiota and metabolic diseases in later life.

Maternal protein restriction induces early-onset glucose intolerance and alters hepatic genes expression in the peroxisome proliferator-activated receptor pathway in offspring

Aims/Introduction

Maternal undernutrition during pregnancy and/or lactation can alter the offspring's response to environmental challenges, and thus increases the risk of the development of metabolic diseases at a later age. However, whether maternal protein restriction can modulate glucose metabolism in the early life of offspring is less understood. Furthermore, we explored the potential underlying mechanisms that illustrate this phenotype.

Materials and Methods

To test this hypothesis, we examined the offspring of C57BL/6J mice at weaning to determine the effects of feeding their mothers a low-protein diet or normal chow diet throughout pregnancy and lactation. Gene array experiments and quantitative real-time polymerase chain reaction were utilized to explore the altered hepatic genes expression.

Results

The offspring of dams fed a low-protein diet had a lower birthweight and bodyweight, impaired glucose tolerance, decreased insulin sensitivity, and decreased serum cholesterol at weaning. Using gene array experiments, 253 differentially expressed genes were identified in the liver tissues of the offspring between the two groups. Bioinformatic analyses showed that all differentially expressed genes were mapped to 11 pathways. We focused on the ‘peroxisome proliferator-activated receptor signaling pathway,’ because peroxisome proliferator-activated receptors have emerged as central regulators of glucose and lipid homeostasis. Quantitative real-time polymerase chain reaction was utilized for the validation of genes in the pathway.

Conclusions

A maternal low-protein diet during pregnancy and lactation promotes early-onset glucose intolerance in the offspring mice, and the altered hepatic genes expression in peroxisome proliferator-activated receptor signaling pathway could play role in regulating this phenomenon.

Oxidative stress in mouse sperm impairs embryo development, fetal growth and alters adiposity and glucose regulation in female offspring

Paternal health cues are able to program the health of the next generation however the mechanism for this transmission is unknown. Reactive oxygen species (ROS) are increased in many paternal pathologies, some of which program offspring health, and are known to induce DNA damage and alter the methylation pattern of chromatin. We therefore investigated whether a chemically induced increase of ROS in sperm impairs embryo, pregnancy and offspring health. Mouse sperm was exposed to 1500 µM of hydrogen peroxide (H₂O₂), which induced oxidative damage, however did not affect sperm motility or the ability to bind and fertilize an oocyte. Sperm treated with H₂O₂ delayed on-time development of subsequent embryos, decreased the ratio of inner cell mass cells (ICM) in the resulting blastocyst and reduced implantation rates. Crown-rump length at day 18 of gestation was also reduced in offspring produced by H₂O₂ treated sperm. Female offspring from H₂O₂ treated sperm were smaller, became glucose intolerant and accumulated increased levels of adipose tissue compared to control female offspring. Interestingly male offspring phenotype was less severe with increases in fat depots only seen at 4 weeks of age, which was restored to that of control offspring later in life, demonstrating sex-specific impacts on offspring. This study implicates elevated sperm ROS concentrations, which are common to many paternal health pathologies, as a mediator of programming offspring for metabolic syndrome and obesity.

Fetal programming of adipose tissue function: an evolutionary perspective

Obesity is an escalating threat of pandemic proportions and has risen to such unrivaled prominence in such a short period of time that it has come to define a whole generation in many countries around the globe. The burden of obesity, however, is not equally shared among the population, with certain ethnicities being more prone to obesity than others, while some appear to be resistant to obesity altogether. The reasons behind this ethnic basis for obesity resistance and susceptibility, however, have remained largely elusive. In recent years, much evidence has shown that the level of brown adipose tissue thermogenesis, which augments energy expenditure and is negatively associated with obesity in both rodents and humans, varies greatly between ethnicities. Interestingly, the incidence of low birth weight, which is associated with an increased propensity for obesity and cardiovascular disease in later life, has also been shown to vary by ethnic background. This review serves to reconcile ethnic variations in BAT development and function with ethnic differences in birth weight outcomes to argue that the variation in obesity susceptibility between ethnic groups may have its origins in the in utero programming of BAT development and function as a result of evolutionary adaptation to cold environments.