Early Life Exposure to Fructose Alters Maternal, Fetal and Neonatal Hepatic Gene Expression and Leads to Sex-Dependent Changes in Lipid Metabolism in Rat Offspring

Maternal nutrition during mid-pregnancy and children's body composition at 7 years of age in the SELMA study

Optimal nutrition during pregnancy is vital for both maternal and child health. Our objective was to explore if prenatal diet is associated with children's height and body fat. Nutrient intake was assessed through a FFQ from 808 pregnant women and summarised to a nutrition index, 'My Nutrition Index' (MNI). The association with children's height and body fat (bioimpedance) was assessed with linear regression models. Secondary analysis was performed with BMI, trunk fat and skinfolds. Overall, higher MNI score was associated with greater height (β = 0·47; (95 % CI 0·00, 0·94), among both sexes. Among boys, higher MNI was associated with 0·15 higher BMI z-scores, 0·12 body fat z-scores, 0·11 trunk fat z-scores, and larger triceps, and triceps + subscapular skinfolds (β = 0·05 and β = 0·06; on the log2 scale) (P-value < 0·05). Among girls, the opposite associations were found with 0·12 lower trunk fat z-scores, and smaller subscapular and suprailiac skinfolds (β = -0·07 and β = -0·10; on the log2 scale) (P-value < 0·05). For skinfold measures, this would represent a ± 1·0 millimetres difference. Unexpectedly, a prenatal diet in line with recommended nutrient intake was associated with higher measures of body fat for boys and opposite to girls at a pre-pubertal stage of development.

Maternal monosaccharide diets evoke cognitive, locomotor, and emotional disturbances in adolescent and young adult offspring rats

Anxiety and depression are the most common mental disorders affecting people worldwide. Recent studies have highlighted that a maternal high-sugar diet (HSD) could be a risk factor for neurobehavioural dysregulations, including mood disorders. Increased consumption of added sugar in food such as refined fructose/glucose can increase the risk of metabolic disorders and impact susceptibility to mental disorders. Furthermore, a few papers have reported disabilities in learning and memory among offspring after maternal HSD, thus suggesting a relationship between maternal nutrition and offspring neurogenesis. In this study, we evaluated the impact of maternal monosaccharide consumption based on a glucose (GLU) or fructose (FRU) diet during pregnancy and lactation in adolescent and young adult offspring rats of both sexes on cognitive, locomotor, and emotional disturbances. Locomotor activity, short-term memory, anxiety-like and depressive-like behavior were evaluated in the offspring. We report for the first time that the maternal GLU or FRU diet is sufficient to evoke anxiety-like behavior among adolescent and young adult offspring. Moreover, we found that maternal monosaccharide diets lead to hyperactivity and depressive-like behavior in male adolescent rats. We also noticed that a maternal FRU diet significantly enhanced novelty-seeking behavior only in young adult male rats. Our novel findings indicated that the maternal monosaccharide diet, especially a diet enriched in FRU, resulted in strong behavioral alterations in offspring rats at early life stages. This study also revealed that male rats were more susceptible to hyperactivity and anxiety- and depressive-like phenotypes than female rats. These results suggest that maternal monosaccharide consumption during pregnancy and lactation is an important factor affecting the emotional status of offspring.

Maternal Fructose Intake, Programmed Mitochondrial Function and Predisposition to Adult Disease

Fructose consumption is now recognised as a major risk factor in the development of metabolic diseases, such as hyperlipidaemia, diabetes, non-alcoholic fatty liver disease and obesity. In addition to environmental, social, and genetic factors, an unfavourable intrauterine environment is now also recognised as an important factor in the progression of, or susceptibility to, metabolic disease during adulthood. Developmental trajectory in the short term, in response to nutrient restriction or excessive nutrient availability, may promote adaptation that serves to maintain organ functionality necessary for immediate survival and foetal development. Consequently, this may lead to decreased function of organ systems when presented with an unfavourable neonatal, adolescent and/or adult nutritional environment. These early events may exacerbate susceptibility to later-life disease since sub-optimal maternal nutrition increases the risk of non-communicable diseases (NCDs) in future generations. Earlier dietary interventions, implemented in pregnant mothers or those considering pregnancy, may have added benefit. Although, the mechanisms by which maternal diets high in fructose and the vertical transmission of maternal metabolic phenotype may lead to the predisposition to adult disease are poorly understood. In this review, we will discuss the potential contribution of excessive fructose intake during pregnancy and how this may lead to developmental reprogramming of mitochondrial function and predisposition to metabolic disease in offspring.

The programming effect of parenteral obesity on the structural and mechanical properties of femora in female rats fed a varied calorie diet during puberty

The study was aimed to ascertain whether continuation or change in the offspring of the diet consumed by the parents modulates, in later life, the previously programmed bone metabolism. We used adult Wistar rats (16 males; 32 females), divided into groups that were fed either a standard (diet S) or a high-energy (diet F). After 90 days of obesity induction, the rats were submitted to obtain female offspring from parents S and F. The offspring stayed with their mothers until 21 days of age (weaning day). Our previous studies have proved the programming effects of parental obesity on the skeletal system of their offspring at the age of 21 days. Weaned female offspring were divided into groups: S/S-parents and offspring fed the S diet; S/F-parents fed the S diet and offspring fed the F diet; F/S-parents fed the diet F and offspring with the diet S; F/F-parents and offspring fed the F diet (F/F). After sacrifice, isolated femurs were assessed by peripheral quantitative computed tomography and by a three-point bending test. The bones were examined at 49 and 90 days of life. We found that nutritional programming has a significant influence on the development and metabolism of the skeletal system in females during growth and maturity. Moreover, the modification of nutrition alters the metabolism of bone tissue, and the osteotropic effects vary depending on the nature of the change, as well as the stage of development. Reducing the caloric content of the diet inhibits the mineralization and decreases the mechanical strength of the bones while increasing the caloric content of the diet has a beneficial osteotropic effect.

Maternal Fructose Intake Causes Developmental Reprogramming of Hepatic Mitochondrial Catalytic Activity and Lipid Metabolism in Weanling and Young Adult Offspring

Excess dietary fructose is a major public health concern, yet little is known about its influence on offspring development and later-life disease when consumed in excess during pregnancy. To determine whether increased maternal fructose intake could have long-term consequences on offspring health, we investigated the effects of 10% w/v fructose water intake during preconception and pregnancy in guinea pigs. Female Dunkin Hartley guinea pigs were fed a control diet (CD) or fructose diet (FD; providing 16% of total daily caloric intake) ad libitum 60 days prior to mating and throughout gestation. Dietary interventions ceased at day of delivery. Offspring were culled at day 21 (D21) (weaning) and at 4 months (4 M) (young adult). Fetal exposure to excess maternal fructose intake significantly increased male and female triglycerides at D21 and 4 M and circulating palmitoleic acid and total omega-7 through day 0 (D0) to 4 M. Proteomic and functional analysis of significantly differentially expressed proteins revealed that FD offspring (D21 and 4 M) had significantly increased mitochondrial metabolic activities of β-oxidation, electron transport chain (ETC) and oxidative phosphorylation and reactive oxygen species production compared to the CD offspring. Western blotting analysis of both FD offspring validated the increased protein abundances of mitochondrial ETC complex II and IV, SREBP-1c and FAS, whereas VDAC1 expression was higher at D21 but lower at 4 M. We provide evidence demonstrating offspring programmed hepatic mitochondrial metabolism and de novo lipogenesis following excess maternal fructose exposure. These underlying asymptomatic programmed pathways may lead to a predisposition to metabolic dysfunction later in life.

Parental overnutrition by carbohydrates in developmental origins of metabolic syndrome

interplay of genomic component and the exposome. Parental diet has been shown to affect offspring metabolic health via multiple epigenetic mechanisms. Excess carbohydrate intake is one of the driving forces of the obesity and metabolic syndrome pandemics. This review summarizes the evidence for the effects of maternal carbohydrate (fructose, sucrose, glucose) overnutrition on the modulation of metabolic syndrome components in the offspring. Despite substantial discrepancies in experimental design, common effects of maternal carbohydrate overnutrition include increased body weight and hepatic lipid content of the "programmed" offspring. However, the administration of sucrose to several rat models leads to apparently favorable metabolic outcomes. Moreover, there is evidence for the role of genomic background in modulating the metabolic programming effect in the form of nutri-epigenomic interaction. Comprehensive, robust studies are needed to resolve the temporal, sex-specific, genetic, epigenetic and nutritional aspects of parental overnutrition in the intergenerational and transgenerational pathogenesis of metabolic syndrome.

Parental overnutrition by carbohydrates in developmental origins of metabolic syndrome

Metabolic syndrome is a prevalent disease resulting from an interplay of genomic component and the exposome. Parental diet has been shown to affect offspring metabolic health via multiple epigenetic mechanisms. Excess carbohydrate intake is one of the driving forces of the obesity and metabolic syndrome pandemics. This review summarizes the evidence for the effects of maternal carbohydrate (fructose, sucrose, glucose) overnutrition on the modulation of metabolic syndrome components in the offspring. Despite substantial discrepancies in experimental design, common effects of maternal carbohydrate overnutrition include increased body weight and hepatic lipid content of the "programmed" offspring. However, the administration of sucrose to several rat models leads to apparently favorable metabolic outcomes. Moreover, there is evidence for the role of genomic background in modulating the metabolic programming effect in the form of nutri-epigenomic interaction. Comprehensive, robust studies are needed to resolve the temporal, sex-specific, genetic, epigenetic and nutritional aspects of parental overnutrition in the intergenerational and transgenerational pathogenesis of metabolic syndrome.

Maternal fructose intake predisposes rat offspring to metabolic disorders via abnormal hepatic programming

Given that fructose consumption has increased by more than 10-fold in recent decades, it is possible that excess maternal fructose consumption causes harmful effects in the next generation. This study attempted to elucidate the mechanism of the harmful effects of excessive maternal fructose intake from the perspective of offspring liver function. Female rats during gestation and lactation were fed water containing fructose, and their offspring were fed normal water. We attempted to elucidate the mechanism of fructose-induced transgenerational toxicity by conducting a longitudinal study focusing on hepatic programming prior to disease onset. Impaired Insulin resistance and decreased high-density lipoprotein-cholesterol levels were observed at 160 days of age. However, metabolic disorders were not observed in 60-day-old offspring. Microarray analysis of 60-day-old offspring livers showed the reduction of hepatic insulin-like growth factor-1 (Igf1) mRNA expression. This reduction continued until the rats were aged 160 days and attenuated Igf1 signaling. Hepatic microRNA-29 (miR-29a) and miR-130a, which target Igf1 mRNA, were also found to be upregulated. Interestingly, these miRNAs were upregulated in the absence of metabolic disorder. In this study, we found that maternal fructose intake resulted in dysregulated expression of Igf1 and its target miRNAs in the offspring liver, and that these offspring were more likely to develop metabolic disorders. Abnormal hepatic programming induced by an imbalanced maternal nutritional environment is maintained throughout life, implying that it may contribute to metabolic disorders.

Maternal Fructose Diet-Induced Developmental Programming

Developmental programming of chronic diseases by perinatal exposures/events is the basic tenet of the developmental origins hypothesis of adult disease (DOHaD). With consumption of fructose becoming more common in the diet, the effect of fructose exposure during pregnancy and lactation is of increasing relevance. Human studies have identified a clear effect of fructose consumption on maternal health, but little is known of the direct or indirect effects on offspring. Animal models have been utilized to evaluate this concept and an association between maternal fructose and offspring chronic disease, including hypertension and metabolic syndrome. This review will address the mechanisms of developmental programming by maternal fructose and potential options for intervention.

Neonatal zingerone protects against the development of high-fructose diet-induced metabolic syndrome in adult Sprague-Dawley rats

During the early postnatal period, dietary manipulations can alter the developmental trajectory of the growing offspring, causing beneficial or adverse health outcomes later in adult life. We investigated the potential preventive effects of neonatal zingerone intake on the development of fructose-induced metabolic derangements in rats.Four-day old male and female Sprague-Dawley rat pups (n = 79) were randomly grouped and administered: 10 ml/kg body weight (bwt) of distilled water (W), 10 ml/kg bwt 20% fructose solution (FS), 10 ml/kg bwt fructose solution + 40 mg/kg bwt of zingerone in distilled water (ZF) or 40 mg/kg bwt of zingerone in distilled water (ZW) pre-weaning. After weaning, W and ZW continued on unlimited tap water, while FS and ZF continued on unlimited fructose solution for 10 weeks. Body mass and food and fluid intake were evaluated, plasma was collected for metabolic assays and visceral fat was quantified.Food intake was decreased, fructose and overall caloric intake were increased due to fructose feeding in both sexes (P < 0.05). When compared with the controls, the high-fructose diet significantly raised the terminal body masses of females (P < 0.0001), concentrations of triglycerides, total cholesterol, LDL-c, TG:HDL-c ratio and visceral fat mass relative to bwt in both sexes (P < 0.05). Zingerone prevented (P < 0.05) the fructose-induced increase in body mass (females) and hypercholesterolemia (both sexes). Levels of HDL-c, glycaemic parameters and adiponectin were not affected by the interventions (P > 0.05). Sex-related differences were observed in food, fluid and caloric intake, terminal mass, cholesterol subtypes and visceral fat percentage (P < 0.05).Zingerone could be used strategically in the neonatal phase as a prophylatic management of high-fructose diet-induced metabolic syndrome.

The high-fructose intake of dams during pregnancy and lactation exerts sex-specific effects on adult rat offspring metabolism

Experimental studies have demonstrated the effects of maternal fructose consumption during pregnancy and lactation on metabolic alterations in their offspring, especially male offspring. However, few studies have focused on female offspring after providing fructose in food to dam rats. Here, we studied whether offspring of both sexes were differentially affected by a maternal high-fructose diet (HFD). For this purpose, Sprague-Dawley rats were fed during pregnancy and lactation with a standard diet (SD) or a HFD (50% w/w). After weaning, offspring were fed an SD; 3 days later, dams were sacrificed, and their offspring were sacrificed on postnatal day 90. Body weight (BW), food and water intake (only for dams), and various biomarkers of metabolic syndrome were measured. When compared to the SD-fed dams, HFD-fed dams had a reduction in BW and food and water intake. Conversely, adiposity, liver weight, liver lipids, and plasma levels of glucose, insulin, cholesterol, triglycerides, and uric acid were increased in HFD-fed dams. Moreover, the BW, food consumption, weight of retroperitoneal fat pads, and liver lipids increased in female and male offspring of HFD-fed dams. Interestingly, the pups of HFD-fed mothers showed increased levels of leptin and insulin resistance and decreased levels of adiponectin which were more pronounced in male offspring than in female offspring. In contrast, a higher increase in BW was shown earlier in female offspring. Thus, high-fructose consumption by dams during pregnancy and lactation led to sex-specific developmental programming of the metabolic syndrome phenotype in adult offspring.

Exposure to high fructose corn syrup during adolescence in the mouse alters hepatic metabolism and the microbiome in a sex-specific manner

KEY POINTS

The prevalence of obesity and non-alcoholic fatty liver disease in children is dramatically increasing at the same time as consumption of foods with a high sugar content. Intake of high fructose corn syrup (HFCS) is a possible aetiology as it is thought to be more lipogenic than glucose. In a mouse model, HFCS intake during adolescence increased fat mass and hepatic lipid levels in male and female mice. However, only males showed impaired glucose tolerance. Multiple metabolites including lipids, bile acids, carbohydrates and amino acids were altered in liver in a sex-specific manner at 6 weeks of age. Some of these changes were also present in adulthood even though HFCS exposure ended at 6 weeks. HFCS significantly altered the gut microbiome, which was associated with changes in key microbial metabolites. These results suggest that HFCS intake during adolescence has profound metabolic changes that are linked to changes in the microbiome and these changes are sex-specific.

ABSTRACT

The rapid increase in obesity, diabetes and fatty liver disease in children over the past 20 years has been linked to increased consumption of high fructose corn syrup (HFCS), making it essential to determine the short- and long-term effects of HFCS during this vulnerable developmental window. We hypothesized that HFCS exposure during adolescence significantly impairs hepatic metabolic signalling pathways and alters gut microbial composition, contributing to changes in energy metabolism with sex-specific effects. C57bl/6J mice with free access to HFCS during adolescence (3-6 weeks of age) underwent glucose tolerance and body composition testing and hepatic metabolomics, gene expression and triglyceride content analysis at 6 and 30 weeks of age (n = 6-8 per sex). At 6 weeks HFCS-exposed mice had significant increases in fat mass, glucose intolerance, hepatic triglycerides (females) and de novo lipogenesis gene expression (ACC, DGAT, FAS, ChREBP, SCD, SREBP, CPT and PPARα) with sex-specific effects. At 30 weeks, HFCS-exposed mice also had abnormalities in glucose tolerance (males) and fat mass (females). HFCS exposure enriched carbohydrate, amino acid, long chain fatty acid and secondary bile acid metabolism at 6 weeks with changes in secondary bile metabolism at 6 and 30 weeks. Microbiome studies performed immediately before and after HFCS exposure identified profound shifts of microbial species in male mice only. In summary, short-term HFCS exposure during adolescence induces fatty liver, alters important metabolic pathways, some of which continue to be altered in adulthood, and changes the microbiome in a sex-specific manner.

Ovariectomy, but not orchiectomy, exacerbates metabolic syndrome after maternal high-fructose intake in adult offspring

High fructose diet is associated with the global metabolic syndrome (MtS) pandemic. MtS develops in early life, depending on prenatal and postnatal nutritional status. We hypothesized that ovariectomy increases the chances of developing MtS in adult offspring following high fructose intake by the mother. Pregnant C57BL/6J mouse dams drank water with or without 20% fructose during pregnancy and lactation. After weaning, the pups were fed regular chow. The offspring were evaluated until they were 7 months of age after the mice in each group, both sexes, were gonadectomized at 4 weeks of age. The offspring (both sexes) of the dams who had high fructose intake developed MtS. In the offspring of dams who drank tap water, orchiectomy increased the body weight gain and body fat accumulation, while ovariectomy increased the body fat accumulation as compared to the sham controls. In the offspring of dams with high fructose intake, orchiectomy decreased the body weight gain, body fat accumulation, visceral adiposity, and glucose intolerance, while ovariectomy exacerbated all of them as compared to the sham operations. These data indicate that ovariectomy encourages the development of MtS in adult offspring after maternal high fructose intake, while orchiectomy prevents the development of MtS. The sex difference indicates that male and female sex hormones play contradictory roles in the development of MtS.

Maternal high-fructose intake during pregnancy and lactation induces metabolic syndrome in adult offspring

BACKGROUND/OBJECTIVES

Nutritional status and food intake during pregnancy and lactation can affect fetal programming. In the current metabolic syndrome epidemic, high-fructose diets have been strongly implicated. This study investigated the effect of maternal high-fructose intake during pregnancy and lactation on the development of metabolic syndrome in adult offspring.

SUBJECTS/METHODS

Drinking water with or without 20% fructose was administered to female C57BL/6J mice over the course of their pregnancy and lactation periods. After weaning, pups ate regular chow. Accu-Chek Performa was used to measure glucose levels, and a tail-cuff method was used to examine systolic blood pressure. Animals were sacrificed at 7 months, their livers were excised, and sections were stained with Oil Red O and hematoxylin and eosin (H&E) staining. Kidneys were collected for gene expression analysis using quantitative real-time Polymerase chain reaction.

RESULTS

Adult offspring exposed to maternal high-fructose intake during pregnancy and lactation presented with heavier body weights, fattier livers, and broader areas under the curve in glucose tolerance test values than control offspring. Serum levels of alanine aminotransferase, aspartate aminotransferase, glucose, triglycerides, and total cholesterol and systolic blood pressure in the maternal high-fructose group were higher than that in controls. However, there were no significant differences in mRNA expressions of renin-angiotensin-aldosterone system genes and sodium transporter genes.

CONCLUSIONS

These results suggest that maternal high-fructose intake during pregnancy and lactation induces metabolic syndrome with hyperglycemia, hypertension, and dyslipidemia in adult offspring.

Fructose-mediated effects on gene expression and epigenetic mechanisms associated with NAFLD pathogenesis

Nonalcoholic fatty liver disease (NAFLD) is a chronic, frequently progressive condition that develops in response to excessive hepatocyte fat accumulation (i.e., steatosis) in the absence of significant alcohol consumption. Liver steatosis develops as a result of imbalanced lipid metabolism, driven largely by increased rates of de novo lipogenesis and hepatic fatty acid uptake and reduced fatty acid oxidation and/or disposal to the circulation. Fructose is a naturally occurring simple sugar, which is most commonly consumed in modern diets in the form of sucrose, a disaccharide comprised of one molecule of fructose covalently bonded with one molecule of glucose. A number of observational and experimental studies have demonstrated detrimental effects of dietary fructose consumption not only on diverse metabolic outcomes such as insulin resistance and obesity, but also on hepatic steatosis and NAFLD-related fibrosis. Despite the compelling evidence that excessive fructose consumption is associated with the presence of NAFLD and may even promote the development and progression of NAFLD to more clinically severe phenotypes, the molecular mechanisms by which fructose elicits effects on dysregulated liver metabolism remain unclear. Emerging data suggest that dietary fructose may directly alter the expression of genes involved in lipid metabolism, including those that increase hepatic fat accumulation or reduce hepatic fat removal. The aim of this review is to summarize the current research supporting a role for dietary fructose intake in the modulation of transcriptomic and epigenetic mechanisms underlying the pathogenesis of NAFLD.

Fructose Consumption During Pregnancy Influences Milk Lipid Composition and Offspring Lipid Profiles in Guinea Pigs

Excess dietary fructose is a major public health concern (1-4). Evidence shows increased fructose intake can cause insulin resistance, hepatic de novo lipogenesis, hypertriglyceridemia, obesity and non-alcoholic fatty liver disease (NAFLD) (5-9). However, little is known about the effects of fructose during pregnancy and its influence on offspring development and predisposition to later-life disease. To determine whether moderately increased maternal fructose intake could have health consequences on offspring, we have investigated the effects of 10% w/v fructose water intake during preconception and pregnancy. Female Dunkin Hartley guinea pigs were fed a control diet (CD) or fructose diet (FD;10% kcal from fructose) ad-libitum 60 days prior to mating and throughout gestation. Offspring were culled at weaning, day 21 (d21). Compared to CD dams, FD dams had altered glucose metabolism and increased milk free fatty acid content. Matsuda-DeFronzo insulin sensitivity index (M-ISI) from OGTT plasma showed no significant difference in whole-body insulin sensitivity between FD and CD dams 60 days post-dietary intervention and during midgestation. Fetal exposure to increased maternal fructose resulted in offspring with significantly altered serum free fatty acids at days 0, 7, 14, and 21 [including pentadecanoic acid (15:0), dma16:0, margaric acid (17:0) palmitoleic acid, total omega-7 and total saturates], increased levels of uric acid and triglycerides were also observed at d21. We have demonstrated that increased fructose intake during pregnancy can cause significant changes in maternal metabolic function and milk composition, which alters offspring metabolism. Taken together, these changes in pregnancy outcomes and feto-maternal condition may underlie their offspring's predisposition to metabolic dysfunction during later-life.

Effects of Maternal Fructose Intake on Perinatal ER-Stress: A Defective XBP1s Nuclear Translocation Affects the ER-stress Resolution

Endoplasmic reticulum (ER) homeostasis is crucial to appropriate cell functioning, and when disturbed, a safeguard system called unfolded protein response (UPR) is activated. Fructose consumption modifies ER homeostasis and has been related to metabolic syndrome. However, fructose sweetened beverages intake is allowed during gestation. Therefore, we investigate whether maternal fructose intake affects the ER status and induces UPR. Thus, administrating liquid fructose (10% w/v) to pregnant rats partially activated the ER-stress in maternal and fetal liver and placenta. In fact, a fructose-induced increase in the levels of pIRE1 (phosphorylated inositol requiring enzyme-1) and its downstream effector, X-box binding protein-1 spliced form (XBP1s), was observed. XBP1s is a key transcription factor, however, XBP1s nuclear translocation and the expression of its target genes were reduced in the liver of the carbohydrate-fed mothers, and specifically diminished in the fetal liver and placenta in the fructose-fed mothers. These XBP1s target genes belong to the ER-associated protein degradation (ERAD) system, used to buffer ER-stress and to restore ER-homeostasis. It is known that XBP1s needs to form a complex with diverse proteins to migrate into the nucleus. Since methylglyoxal (MGO) content, a precursor of advanced glycation endproducts (AGE), was augmented in the three tissues in the fructose-fed mothers and has been related to interfere with the functioning of many proteins, the role of MGO in XBP1s migration should not be discarded. In conclusion, maternal fructose intake produces ER-stress, but without XBP1s nuclear migration. Therefore, a complete activation of UPR that would resolve ER-stress is lacking. A state of fructose-induced oxidative stress is probably involved.

Effects of consuming sugars and alternative sweeteners during pregnancy on maternal and child health: evidence for a secondhand sugar effect

Consumption of sugar and alternative low- or no-energy sweeteners has increased in recent decades. However, it is still uncertain how consumption of sugar and alternative sweeteners during pregnancy affects pregnancy outcomes and long-term offspring health. This review aims to collate the available evidence surrounding the consequences of sugar and alternative sweetener consumption during pregnancy, a so-called secondhand sugar effect. We found evidence that sugar consumption during pregnancy may contribute to increased gestational weight gain and the development of pregnancy complications, including gestational diabetes, preeclampsia and preterm birth. Further, we found a growing body of the animal and human evidence that maternal sugar intake during pregnancy may impact neonatal and childhood metabolism, taste perception and obesity risk. Emerging evidence also suggests that both maternal and paternal preconception sugar intakes are linked to offspring metabolic outcomes, perhaps via epigenetic alterations to the germline. While there have been fewer studies of the impacts of alternative sweetener consumption before and during pregnancy, there is some evidence to suggest effects on infant outcomes including preterm birth risk, increased infant body composition and offspring preference for sweet foods, although mechanisms are unclear. We conclude that preconception and gestational sugar and alternative sweetener consumption may negatively impact pregnancy outcomes and offspring health and that there is a need for further observational, mechanistic and intervention research in this area.

The protective effect of neonatal oral administration of oleanolic acid against the subsequent development of fructose-induced metabolic dysfunction in male and female rats

BACKGROUND

Consumption of fructose-rich diets has been implicated in the increasing global prevalence of metabolic syndrome (MetS). Interventions during periods of early ontogenic developmental plasticity can cause epigenetic changes which program metabolism for positive or negative health benefits later in life. The phytochemical oleanolic acid (OA) possesses anti-diabetic and anti-obesity effects. We investigated the potential protective effects of neonatal administration of OA on the subsequent development of high fructose diet-induced metabolic dysfunction in rats.

METHOD

Male and female (N = 112) suckling rats were randomly assigned to four groups and administered orally: distilled water (DW), oleanolic acid (OA; 60 mg/kg), high-fructose solution (HF; 20% w/v) or OA + HF for 7 days. The rats were weaned onto normal commercial rat chow up to day 55. From day 56, half of the rats in each treatment group were continued on plain water and the rest on a high fructose solution as drinking fluid for 8 weeks. On day 110, the rats were subjected to an oral glucose tolerance test and then euthanased on day 112. Tissue and blood samples were collected to determine the effects of the treatments on visceral fat pad mass, fasting plasma levels of cholesterol, insulin, glucose, triglycerides, insulin resistance (HOMA-IR) and glucose tolerance.

RESULTS

Rats which consumed fructose as neonates and then later as adults (HF + F) and those which consumed fructose only in adulthood (DW + F) had significant increases in terminal body mass (females only), visceral fat mass (males and females), serum triglycerides (females only), epididymal fat (males only), fasting plasma glucose (males and females), impaired glucose metabolism (females only), β-cell dysfunction and insulin resistance (males and females) compared to the other treatment groups (P < 0.05). There were no differences in fasting serum cholesterol levels across all treatment groups in both male and female rats (P > 0.05).

CONCLUSION

We conclude that neonatal oral administration of OA during the critical window of developmental plasticity protected against the development of health outcomes associated with fructose-induced metabolic disorders in the rats.

Maternal fructose induces gender-dependent changes in both LXRα promoter methylation and cholesterol metabolism in progeny

Fructose consumption from added sugars correlates with the epidemic rise in obesity, metabolic syndrome and cardiovascular diseases. However, consumption of beverages containing fructose is allowed during gestation. We have investigated whether maternal fructose intake produces subsequent changes in cholesterol metabolism of progeny. Carbohydrates were supplied to pregnant rats in drinking water (10% w/v solution) throughout gestation. Adult male and female descendants from fructose-fed, control or glucose-fed mothers were studied. Male offspring from fructose-fed mothers had elevated plasma HDL-cholesterol levels, whereas female progeny from fructose-fed mothers presented lower levels of non-HDL cholesterol vs. the other two groups. Liver X-receptor (LXR), an important regulator of cholesterol metabolism, and its target genes such as scavenger receptor B1, ATP-binding cassette (ABC)G5 and cholesterol 7-alpha hydroxylase showed decreased gene expression in males from fructose-fed mothers and the opposite in the female progeny. Moreover, the expression of a number of LXRα target genes related to lipogenesis paralleled to that for LXRα expression. In accordance with this, LXRα gene promoter methylation was increased in males from fructose-fed mothers and decreased in the corresponding group of females. Surprisingly, plasma folic acid levels, an important methyl-group donor, were augmented in males from fructose-fed mothers and diminished in female offspring. Maternal fructose intake produces a fetal programming that influences, in a gender-dependent manner, the transcription factor LXRα epigenetically, and both hepatic mRNA gene expression and plasma parameters of cholesterol metabolism in adult progeny. Changes in the LXRα promoter methylation might be related to the availability of the methyl donor folate.

High Fructose Intake During Pregnancy in Rats Influences the Maternal Microbiome and Gut Development in the Offspring

Studies in pregnant women indicate the maternal microbiome changes during pregnancy so as to benefit the mother and fetus. In contrast, disruption of the maternal microbiota around birth can compromise normal bacterial colonisation of the infant's gastrointestinal tract. This may then inhibit development of the gut so as to increase susceptibility to inflammation and reduce barrier function. The impact of modulating fructose intake on the maternal microbiome through pregnancy is unknown, therefore we examined the effect of fructose supplementation on the maternal microbiome together with the immediate and next generation effects in the offspring. Wistar rat dams were divided into control and fructose fed groups that received 10% fructose in their drinking water from 8 weeks of age and throughout pregnancy (10-13 weeks). Maternal fecal and blood samples were collected pre-mating (9 weeks) and during early (gestational day 4-7) and late pregnancy (gestational day 19-21). We show supplementation of the maternal diet with fructose appears to significantly modulate the maternal microbiome, with a significant reduction in Lactobacillus and Bacteroides. In offspring maintained on this diet up to pregnancy and term there was a reduction in gene expression of markers of gut barrier function that could adversely affect its function. An exacerbated insulin response to pregnancy, reduced birth weight, but increased fat mass was also observed in these offspring. In conclusion dietary supplementation with fructose modulates the maternal microbiome in ways that could adversely affect fetal growth and later gut development.

The effect of maternal intake of sucrose or high-fructose corn syrup (HFCS)-55 during gestation and lactation on lipogenic gene expression in rat offspring at 3 and 12 weeks of age

Perinatal exposure to sucrose or high-fructose corn syrup-55 (HFCS-55) in rats has previously been associated with altered hepatic fat content and composition post-weaning, although the effects on hepatic metabolism are unknown. The current study aimed to determine the sex-specific effects of maternal consumption of sucrose or HFCS-55 on the expression of hepatic lipogenic genes in the offspring. Liver samples were collected from offspring of albino Wistar rats provided with ad libitum access to either water (control), 10% sucrose or 10% HFCS-55 solution during pregnancy and lactation at 3 weeks (control n=16, sucrose n=22, HFCS-55 n=16) and 12 weeks (control n=16, sucrose n=10, HFCS-55 n=16) of age. Hepatic expression of the transcription factors such as carbohydrate response element-binding protein, sterol regulatory element-binding protein-1c and downstream genes was determined by quantitative real-time PCR. Sucrose-exposed offspring had higher hepatic SREBP-1c messenger RNA expression compared with control and HFCS-55 groups at both 3 weeks (P=0.01) and 12 weeks (P=0.03) of age. There were no differences in the expression of other hepatic lipogenic genes between groups at either 3 or 12 weeks. Thus, perinatal exposure to sucrose may be more detrimental to offspring hepatic metabolism compared with HFCS-55, independent of sex, and it will be important to evaluate the longer-term effects of perinatal sucrose exposure in future studies.

Neonatal intake of oleanolic acid attenuates the subsequent development of high fructose diet-induced non-alcoholic fatty liver disease in rats

Dietary manipulations during the early postnatal period are associated with the development of metabolic disorders including non-alcoholic fatty liver disease (NAFLD) or long-term protection against metabolic dysfunction. We investigated the potential hepatoprotective effects of neonatal administration of oleanolic acid (OA), a phytochemical, on the subsequent development in adulthood, of dietary fructose-induced NAFLD. Male and female suckling rats (n=112) were gavaged with; distilled water (DW), OA (60 mg/kg), high fructose solution (HF; 20% w/v) and OA+HF (OAHF) for 7 days. The rats were weaned onto normal rat chow on day 21 up to day 55. From day 56, half of the rats in each treatment group were continued on plain water or HF as drinking fluid for 8 weeks. Hepatic lipid accumulation and hepatic histomorphometry were then determined. Fructose consumption in adulthood following neonatal fructose intake (HF+F) caused a 47-49% increase in hepatic lipid content of both male and female rats (P<0.05). However, fructose administered in adulthood only, caused a significant increase (P<0.05) in liver lipid content in females only. NAFLD activity scores for inflammation and steatosis were higher in the fructose-fed rats compared with other groups (P<0.05). Steatosis, low-grade inflammation and fibrosis were observed in rats that received HF+F. NAFLD area fraction for fibrosis was three times higher in rats that received fructose neonatally and in adulthood compared with the rats in the negative control group (P<0.05). Treatment with OA during a critical window of developmental plasticity in rats prevented the development of fructose-induced NAFLD.

Maternal dietary free or bound fructose diversely influence developmental programming of lipogenesis

Background

Maternal dietary choices throughout preconception, pregnancy, and lactation irreversibly affect the development of fetal tissues and organs, known as fetal programming. Recommendations tend to emphasize reducing added sugars. However, the impact of maternal dietary free or bound fructose in added sugars on developmental programming of lipogenesis is unknown.

Methods

Virgin Sprague-Dawley rats were randomly divided into five groups. Rats were given feed and plain water (control) or water containing maltodextrin (vehicle), fructose, high-fructose corn syrup (HFCS) containing 55% fructose, sucrose (20% w/v) for 12 weeks before mating and throughout the pregnancy and lactation periods. Body weight, water, and feed intake were measured throughout the study. At the end of the lactation period, blood was drawn to determine the fasting levels of glucose, insulin, triglycerides, and non-esterified fatty acids (NEFA) in blood. Triglycerides and acetyl Co-A Carboxylase-1 (ACC1) levels in livers were analyzed, and insulin resistance was calculated.

Results

The energy intake of dams in the HFCS group was higher than in the fructose group, while weight gain was less in the HFCS group than in the fructose group. HFCS resulted in greater insulin resistance in dams, whereas free fructose had a robust effect on the fetal programming of insulin resistance. Free fructose and HFCS in the maternal diet increased blood and liver triglycerides and NEFA content in pups. Furthermore, fructose and HFCS exposure increased phosphorylated ACC1 as compared to maltodextrin and control, indicating greater fatty acid synthesis in pups and dams.

Conclusion

Different types of added sugar in the maternal diet have different metabolic effects on the developmental programming of lipogenesis. Consequently, high fructose intake via processed foods may increase the risk for chronic diseases, and free fructose might contribute to developmental programming of chronic diseases more than bound fructose.

Effect of neonatal orally administered S-allyl cysteine in high-fructose diet fed Wistar rats

S-allyl cysteine (SAC) has antioxidant, antidiabetic and antiobesity properties. We hypothesized that neonatal oral administration of SAC would protect rats against neonatal and adulthood high-fructose diet-induced adverse metabolic outcomes in adulthood. In total, 112 (males=56; females=56), 4-day-old Wistar rat pups were randomly allocated to groups and administered the following treatment regimens daily for 15 days from postnatal day (PND) 6-20: group I - 10 ml/kg distilled water, group II - 10 ml/kg 20% fructose solution (FS), group III - 150 mg/kg SAC and group IV - SAC+FS. On PND 21, the pups were weaned and allowed to grow on a standard rat chow (SRC) until PND 56. The rats from each treatment regimen were then randomly split into two subgroups: one on a SRC and plain drinking water and another on SRC and 20% FS as drinking fluid and then subjected to these treatment regimens for 8 weeks after which they were euthanized and tissues collected for analyzes. Neonatal oral administration of SAC attenuated the neonatal high-fructose diet-induced programming for hepatic lipid accretion in adulthood but not against adulthood high-fructose diet-induced visceral obesity. Neonatal oral administration of SAC programmes for protection against neonatal fructose-induced programming for hepatic lipid accumulation thus could potentially protect against fat-mediated liver derangements in adult life.

Conditional postnatal deletion of the neonatal murine hepatic circadian gene, Npas2, alters the gut microbiome following restricted feeding

BACKGROUND

We have recently shown in both non-human primates and in rodents that fetal and neonatal hepatic expression of the circadian transcription factor, Npas2, is modulated by a high fat maternal diet and plays a critical role in establishing life-long metabolic homeostasis. Similarly, we and others have also established the importance of the maternal and early postnatal diet on establishment of the early gut microbiome.

OBJECTIVE

We hypothesized that altered circadian gene expression solely in the neonatal liver would result in gut microbiome dysbiosis, especially with diet-induced metabolic stress (ie, restricted feeding). Using a murine model in which we conditionally knock out Npas2 in the neonatal liver, we aimed to determine the role of the circadian machinery in gut dysbiosis with restricted feeding.

STUDY DESIGN

We collected fecal samples from liver Npas2 conditional knockout (n = 11) and wild-type (n = 13) reproductive-aged mice before (study day 0) and after the restricted feeding study (study day 17). Extracted DNA was sequenced using the MiSeq Illumina platform using primers specific for the V4 region of the 16S ribosomal DNA gene. The resulting sequences were quality filtered, aligned, and assigned taxonomy. Principal coordinate analysis was performed on unweighted and weighted UniFrac distances between samples with a permutation analysis of variance to assess clustering significance between groups. Microbial taxa that significantly differ between groups of interest was determined using linear discriminate analysis effect size and randomForrest.

RESULTS

Principal coordinate analysis performed on weighted UniFrac distances between male conditional knockout and wild-type cohorts revealed that the gut microbiome of the mice did not differ by genotype at the start of the restricted feeding study but did differ by virtue of genotype at the end of the study (P = .001). Moreover, these differences could be at least partially attributed to restricted feeding-associated alterations in relative abundance of the Bacteroides genus, which has been implicated as crucial to establishing a healthy gut microbiome early in development.

CONCLUSION

Here we have provided an initial key insight into the interplay between neonatal establishment of the peripheral circadian clock in the liver and the ability of the gut microbiome to respond to dietary and metabolic stress. Because Npas2 expression in the liver is a target of maternal high-fat diet-induced metabolic perturbations during fetal development, we speculate that these findings have potential implications in the long-term metabolic health of their offspring.

Maternal Macronutrient Consumption and the Developmental Origins of Metabolic Disease in the Offspring

Recent research aimed at understanding the rise in obesity and cardiometabolic disease in children suggests that suboptimal maternal nutrition conditions organ systems and physiological responses in the offspring contributing to disease development. Understanding the mechanisms by which the macronutrient composition of the maternal diet during pregnancy or lactation affects health outcomes in the offspring may lead to new maternal nutrition recommendations, disease prevention strategies and therapies that reduce the increasing incidence of cardiometabolic disease in children. Recent mechanistic animal model research has identified how excess fats and sugars in the maternal diet alter offspring glucose tolerance, insulin signaling and metabolism. Maternal nutrition appears to influence epigenetic alterations in the offspring and the programming of gene expression in key metabolic pathways. This review is focused on experimental studies in animal models that have investigated mechanisms of how maternal consumption of macronutrients affects cardiometabolic disease development in the offspring. Future research using "-omic" technologies is essential to elucidate the mechanisms of how altered maternal macronutrient consumption influences the development of disease in the offspring.

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

KEY POINTS

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

ABSTRACT

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

Dietary fructose as a risk factor for non-alcoholic fatty liver disease (NAFLD)

Glucose is a major energy source for the entire body, while fructose metabolism occurs mainly in the liver. Fructose consumption has increased over the last decade globally and is suspected to contribute to the increased incidence of non-alcoholic fatty liver disease (NAFLD). NAFLD is a manifestation of metabolic syndrome affecting about one-third of the population worldwide and has progressive pathological potential for liver cirrhosis and cancer through non-alcoholic steatohepatitis (NASH). Here we have reviewed the possible contribution of fructose to the pathophysiology of NAFLD. We critically summarize the current findings about several regulators, and their potential mechanisms, that have been studied in humans and animal models in response to fructose exposure. A novel hypothesis on fructose-dependent perturbation of liver regeneration and metabolism is advanced. Fructose intake could affect inflammatory and metabolic processes, liver function, gut microbiota, and portal endotoxin influx. The role of the brain in controlling fructose ingestion and the subsequent development of NAFLD is highlighted. Although the importance for fructose (over)consumption for NAFLD in humans is still debated and comprehensive intervention studies are invited, understanding of how fructose intake can favor these pathological processes is crucial for the development of appropriate noninvasive diagnostic and therapeutic approaches to detect and treat these metabolic effects. Still, lifestyle modification, to lessen the consumption of fructose-containing products, and physical exercise are major measures against NAFLD. Finally, promising drugs against fructose-induced insulin resistance and hepatic dysfunction that are emerging from studies in rodents are reviewed, but need further validation in human patients.

Fructose during pregnancy provokes fetal oxidative stress: The key role of the placental heme oxygenase-1

SCOPE

One of the features of metabolic syndrome caused by liquid fructose intake is an impairment of redox status. We have investigated whether maternal fructose ingestion modifies the redox status in pregnant rats and their fetuses.

METHODS AND RESULTS

Fructose (10% wt/vol) in the drinking water of rats throughout gestation, leads to maternal hepatic oxidative stress. However, this change was also observed in glucose-fed rats and, in fact, both carbohydrates produced a decrease in antioxidant enzyme activity. Surprisingly, mothers fed carbohydrates displayed low plasma lipid oxidation. In contrast, fetuses from fructose-fed mothers showed elevated levels of plasma lipoperoxides versus fetuses from control or glucose-fed mothers. Interestingly, a clearly augmented oxidative stress was observed in placenta of fructose-fed mothers, accompanied by a lower expression of the transcription factor Nuclear factor-erythroid 2-related factor-2 (Nrf2) and its target gene, heme oxygenase-1 (HO-1), a potent antioxidant molecule. Moreover, histone deacetylase 3 (HDAC3) that has been proposed to upregulate HO-1 expression by stabilizing Nrf2, exhibited a diminished expression in placenta of fructose-supplemented mothers.

CONCLUSIONS

Maternal fructose intake provoked an imbalanced redox status in placenta and a clear diminution of HO-1 expression, which could be responsible for the augmented oxidative stress found in their fetuses.

A review of fundamental principles for animal models of DOHaD research: an Australian perspective

Epidemiology formed the basis of ‘the Barker hypothesis’, the concept of ‘developmental programming’ and today’s discipline of the Developmental Origins of Health and Disease (DOHaD). Animal experimentation provided proof of the underlying concepts, and continues to generate knowledge of underlying mechanisms. Interventions in humans, based on DOHaD principles, will be informed by experiments in animals. As knowledge in this discipline has accumulated, from studies of humans and other animals, the complexity of interactions between genome, environment and epigenetics, has been revealed. The vast nature of programming stimuli and breadth of effects is becoming known. As a result of our accumulating knowledge we now appreciate the impact of many variables that contribute to programmed outcomes. To guide further animal research in this field, the Australia and New Zealand DOHaD society (ANZ DOHaD) Animals Models of DOHaD Research Working Group convened at the 2nd Annual ANZ DOHaD Congress in Melbourne, Australia in April 2015. This review summarizes the contributions of animal research to the understanding of DOHaD, and makes recommendations for the design and conduct of animal experiments to maximize relevance, reproducibility and translation of knowledge into improving health and well-being.

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.

High Risk of Metabolic and Adipose Tissue Dysfunctions in Adult Male Progeny, Due to Prenatal and Adulthood Malnutrition Induced by Fructose Rich Diet

The aim of this work was to determine the effect of a fructose rich diet (FRD) consumed by the pregnant mother on the endocrine-metabolic and in vivo and in vitro adipose tissue (AT) functions of the male offspring in adulthood. At 60 days of age, rats born to FRD-fed mothers (F) showed impaired glucose tolerance after glucose overload and high circulating levels of leptin (LEP). Despite the diminished mass of retroperitoneal AT, this tissue was characterized by enhanced LEP gene expression, and hypertrophic adipocytes secreting in vitro larger amounts of LEP. Analyses of stromal vascular fraction composition by flow cytometry revealed a reduced number of adipocyte precursor cells. Additionally, 60 day-old control (C) and F male rats were subjected to control diet (CC and FC animals) or FRD (CF and FF rats) for three weeks. FF animals were heavier and consumed more calories. Their metabolic-endocrine parameters were aggravated; they developed severe hyperglycemia, hypertriglyceridemia, hyperleptinemia and augmented AT mass with hypertrophic adipocytes. Our study highlights that manipulation of maternal diet induced an offspring phenotype mainly imprinted with a severely unhealthy adipogenic process with undesirable endocrine-metabolic consequences, putting them at high risk for developing a diabetic state.

The Programming Power of the Placenta

Size at birth is a critical determinant of life expectancy, and is dependent primarily on the placental supply of nutrients. However, the placenta is not just a passive organ for the materno-fetal transfer of nutrients and oxygen. Studies show that the placenta can adapt morphologically and functionally to optimize substrate supply, and thus fetal growth, under adverse intrauterine conditions. These adaptations help meet the fetal drive for growth, and their effectiveness will determine the amount and relative proportions of specific metabolic substrates supplied to the fetus at different stages of development. This flow of nutrients will ultimately program physiological systems at the gene, cell, tissue, organ, and system levels, and inadequacies can cause permanent structural and functional changes that lead to overt disease, particularly with increasing age. This review examines the environmental regulation of the placental phenotype with particular emphasis on the impact of maternal nutritional challenges and oxygen scarcity in mice, rats and guinea pigs. It also focuses on the effects of such conditions on fetal growth and the developmental programming of disease postnatally. A challenge for future research is to link placental structure and function with clinical phenotypes in the offspring.

SIRT1 Disruption in Human Fetal Hepatocytes Leads to Increased Accumulation of Glucose and Lipids

There are unprecedented epidemics of obesity, such as type II diabetes and non-alcoholic fatty liver diseases (NAFLD) in developed countries. A concerning percentage of American children are being affected by obesity and NAFLD. Studies have suggested that the maternal environment in utero might play a role in the development of these diseases later in life. In this study, we documented that inhibiting SIRT1 signaling in human fetal hepatocytes rapidly led to an increase in intracellular glucose and lipids levels. More importantly, both de novo lipogenesis and gluconeogenesis related genes were upregulated upon SIRT1 inhibition. The AKT/FOXO1 pathway, a major negative regulator of gluconeogenesis, was decreased in the human fetal hepatocytes inhibited for SIRT1, consistent with the higher level of gluconeogenesis. These results indicate that SIRT1 is an important regulator of lipid and carbohydrate metabolisms within human fetal hepatocytes, acting as an adaptive transcriptional response to environmental changes.