Consumption of sucrose, but not high fructose corn syrup, leads to increased adiposity and dyslipidaemia in the pregnant and lactating rat

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.

Metabolic and behavioural effects in offspring exposed to maternal sucrose consumption: a systematic review and meta-analysis of data from rodent models

Consumption of sugar-sweetened beverages (SSBs) during pregnancy has been associated with childhood obesity. Research in which rodent dams have been given high-fat/high-sugar diets has consistently found metabolic alterations in their offspring. However, what remains unclear is the potential impact on the developing fetus of giving sugar in isolation at concentrations similar to SSBs to the mothers. Therefore, we conducted a systematic review and meta-analysis (Protocol No: 127115 on Prospero) to identify potential relationships between maternal sucrose consumption and metabolic outcomes in offspring of rodent (rat or mouse) models. We analysed studies that provided rodent mothers dams with access to sucrose solutions (8-20% w/v) prior to conception, during pregnancy and/or lactation and that reported offspring outcomes of body weight (BW), body composition and glycaemic control. Following a systematic search of four databases (PubMed, EMBASE, Web of Science and Scopus) performed on 15 January 2019, maternal and offspring data from 15 papers were identified for inclusion. Only rat studies were identified. Meta-analyses were performed on standardised mean differences for maternal and offspring BW and fasting glucose levels, with subgroup analyses of strain, sucrose concentration, exposure period and sex of offspring. A bias towards the inclusion of only data from male offspring was identified and this limited interpretation of potential sexually dimorphic outcomes. Maternal sucrose exposure was associated with an increased risk of obesity and poor glucose disposal in adult and aged offspring.

Maternal fructose consumption down-regulates Lxra expression via miR-206-mediated regulation

Maternal fructose consumption affects the metabolic functions of offspring later in life. However, the molecular mechanism remains poorly understood. Differences of microRNA expression profile and DNA methylation status are a candidate mechanism to explain the developmental programming that contributes to the development of a metabolic disorder. This study examined the transgenerational effect of maternal fructose consumption from the perspective of epigenetic modification. To do this, we collected serum and liver tissues from male offspring rats that were exposed to maternal distilled water or 20% fructose water during gestation and lactation. A decreased serum high-density lipoprotein cholesterol (HDL-C) level was observed in the offspring of fructose-fed dams at postnatal day (PD) 160. Given research indicating a role of liver X receptor alpha (LXRA) in cholesterol metabolism, we analyzed Lxra expression. Real-time polymerase chain reaction analysis demonstrated that offspring that were delivered from fructose-fed dams exhibited decreased Lxra gene expression in their liver tissue. There is a well-established association between Lxra expression and the level of DNA methylation and miR-206 expression. Pyrosequencing assays revealed no differences in the level of DNA methylation in the Lxra promoter region, whereas miR-206 expression was increased in the liver at PD 60 and 160. Our data indicate that early-life exposure to maternal fructose results in changing of miR-206 expression level in the liver that suppresses the expression of Lxra. This phenomenon may be associated with the decreased serum HDL-C level in offspring.

Potential effect of maternal dietary sucrose or fructose syrup on CD36, leptin, and ghrelin-mediated fetal programming of obesity

The influence of HFCS (high fructose corn syrup - free fructose) and sucrose (bound fructose) on fetal appetite signals is unknown. This study aimed to determine the effects of HFCS or sucrose on the peptide-mediated appetite regulation in fetal programming of obesity. Sprague Dawley female rats were administered feed and plain water (control) or water containing maltodextrin (vehicle), sucrose, fructose, or HFCS (20%, w/v) for 12 weeks before mating and throughout pregnancy and lactation (n_dams = 31; n_pups = 207). Maternal chow-feed consumption in the HFCS and sucrose groups and sugar-added drink consumption in the HFCS group were higher compared to the vehicle and control groups (P < 0.05). The total body fat accumulated in sucrose, fructose, and HFCS groups in dams and pups was higher than those in the vehicle and control groups (P < 0.05). The HFCS groups showed lower plasma leptin levels and higher ghrelin levels. Soluble CD36 levels in plasma and tongue samples were high in HFCS groups of dams and pups (P < 0.05). Rather than bound fructose, the free fructose from the maternal diet contributes to the programming of obesity through the disruption of leptin, ghrelin, and CD36 expression involved in appetite regulation.

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.

Diet-dependence of metabolic perturbations mediated by the endocrine disruptor tolylfluanid

Emerging evidence implicates environmental endocrine-disrupting chemicals (EDCs) in the pathogenesis of metabolic diseases such as obesity and diabetes; however, the interactions between EDCs and traditional risk factors in disease pathogenesis remain incompletely characterized. The present study interrogates the interaction of the EDC tolylfluanid (TF) and traditional dietary stressors in the promotion of metabolic dysfunction. Eight-week-old male C57BL/6 mice were fed a high-fat, high-sucrose diet (HFHSD) or a high-sucrose diet (HSD), with or without TF supplementation at 100 μg/g, for 12 weeks. Food intake, body weight and visceral adiposity were quantified. Glucose homeostasis was interrogated by intraperitoneal glucose and insulin tolerance tests at 9 and 10 weeks of exposure, respectively. After 12 weeks of dietary exposure, metabolic cage analyses were performed to interrogate nutrient handling and energy expenditure. In the background of an HFHSD, TF promoted glucose intolerance; however, weight gain and insulin sensitivity were unchanged, and visceral adiposity was reduced. In the background of an HSD, TF increased visceral adiposity; however, glucose tolerance and insulin sensitivity were unchanged, while weight gain was reduced. Thus, these analyses reveal that the metabolic perturbations induced by dietary exposure to TF, including the directionality of alterations in body weight gain, visceral adiposity and glucose homeostasis, are influenced by dietary macronutrient composition, suggesting that populations may exhibit distinct metabolic risks based on their unique dietary characteristics.

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.

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.

Effects of post-suckling n-3 polyunsaturated fatty acids: prevention of dyslipidemia and liver steatosis induced in rats by a sucrose-rich diet during pre- and post-natal life

The interaction between fetal programming and the post-natal environment suggests that the post-natal diet could amplify or attenuate programmed outcomes. We investigated whether dietary n-3 long-chain polyunsaturated fatty acids (n-3 PUFAs) at weaning resulted in an amelioration of dyslipidemia, adiposity and liver steatosis that was induced by a sucrose-rich diet (SRD; where the fat source is corn oil) from the onset of pregnancy up to adulthood. During pregnancy and lactation, dams were fed an SRD or the standard powdered rodent commercial diet (RD). At weaning and until 150 days of life, male offspring from SRD-dams were divided into two groups and fed an SRD or SRD-with-fish oil [where 6% of the corn oil was partially replaced by fish oil (FO) 5% and corn oil (CO) 1%], forming SRD-SRD or SRD-FO groups. Male offspring from RD-dams continued with RD up to the end of the experimental period, forming an RD-RD group. The presence of FO in the weaning diet showed the following: prevention of hypertriglyceridemia and liver steatosis, together with increased lipogenic enzyme activity caused by a maternal SRD; the complete normalization of CPT I activity and PPARα protein mass levels; a slight but not statistically significant accretion of visceral adiposity; and limited body fat content and reduced plasma free fatty acid levels. All of these results were observed even in the presence of a high-sucrose diet challenge after weaning. SRD-dams' breast milk showed a more saturated fatty acid composition. These results suggest the capacity of n-3 PUFAs to overcome some adverse outcomes induced by a maternal and post-weaning sucrose-rich diet.

Pre-gestational overweight in guinea pig sows induces fetal vascular dysfunction and increased rate of large and small fetuses

In humans, obesity before and during pregnancy is associated with both fetal macrosomia and growth restriction, and long-term cardiovascular risk in the offspring. We aimed to determine whether overweighted pregnant guinea pig sows results in an increased fetal weight at term and the effects on the vascular reactivity in fetal systemic and umbilical arteries. Pregnant guinea pigs were classified as control (n=4) or high weight (HWS, n=5) according to their pre-mating weight, and their fetuses extracted at 0.9 gestation (~60 days). Segments of fetal femoral and umbilical arteries were mounted in a wire myograph, where the contractile response to KCl (5-125 mM), and the relaxation to nitric oxide synthase-dependent agents (insulin, 10-10-10-7 and acetylcholine, 10-10-10-5) and nitric oxide [sodium nitroprusside (SNP), 10-10-10-5] were determined. Fetuses from HWS (HWSF) were grouped according to their body weight as low (85 g) fetal weight, based on the confidence interval (76.5-84.9 g) of the control group. No HWSF were observed in the normal range. Umbilical arteries from HWSF showed a lower response to KCl and insulin compared with controls, but a comparable response with SNP. Conversely, femoral arteries from HWSF showed an increased response to KCl and acetylcholine, along with a decreased sensitivity to SNP. These data show that overweight sows have altered fetal growth along gestation. Further, large and small fetuses from obese guinea pig sows showed altered vascular reactivity at umbilical and systemic vessels, which potentially associates with long-term cardiovascular risk.