Effect of feeding a high-fat diet during pregnancy on glucose metabolism in the rat

Fructooligosaccharide ameliorates high-fat induced intrauterine inflammation and improves lipid profile in the hamster offspring

Maternal high-fat diet (HFD) often results in intrauterine and feto-placental inflammation, and increases the risks of fetal programming of metabolic diseases. Intake of prebiotic is reported beneficial. However, its effects on HFD during pregnancy and lactation is not known. We evaluated the maternal intake of fructooligosaccharide (FOS) and its impact on placental inflammation, offspring's adiposity, glucose, and lipid metabolism in their later life. Female Golden Syrian hamsters were fed with a control diet (CD, 26.4 % energy from fat) or HFD (60.7% energy from fat) in the presence or absence of FOS from preconception until lactation. All pups were switched over to CD after lactation and continued until the end. Placental inflammation was upregulated in HFD-fed dam, as measured by a high concentration of hsCRP in the serum and amniotic fluid. Neutrophil infiltration was significantly increased in the decidua through the chorionic layer of the placenta. The expression of pro-inflammatory cytokines such as COX2, NFκβ, IL-8, TGFβ mRNA was increased in the chorioamniotic membrane (P <.05). The HFD/CD hamsters had more adiposity, higher triglyceride, and low HDL at 12 months of age compared to CD/CD (P <.05). However, HFD+FOS/CD-fed hamsters prevented adverse effects such as placental inflammation, neutrophil infiltration, glucose, and lipid profiles in the offspring (P <.05). Anti-inflammatory and lipid-lowering effects of FOS may reduce placental inflammation by lowering neutrophil infiltration and decreasing the production of pro-inflammatory cytokines. Intake of FOS during pregnancy may be beneficial in maintaining lipid metabolism and preventing excess adiposity for mother and their offspring.

Lycopene Modulates Placental Health and Fetal Development Under High-Fat Diet During Pregnancy of Rats

Lycopene plays an important role in improving immunity, promoting antioxidant capacity, and regulating fat metabolism. The placenta, an important organ for nutrients exchange between mother and child during pregnancy, directly affects fetal development. This study aims to characterize effects of lycopene on placental health and fetal development under a high-fat diet, and utilize RNA sequencing (RNA-seq) to investigate and integrate the differences of molecular pathways and biological processes in placenta. For placental health, high-fat diet during pregnancy increases placental oxidative stress, inflammation, and fat deposition. However, lycopene reduces the negative effects of high-fat diet on placenta to some extent, and further promotes fetal development. Under high-fat diet, lycopene reduces the levels of Interleukin 17 (IL-17), Interleukin 6 (IL-6), and tumor necrosis factor α (TNF-α) in placenta (p < 0.05) through the IL-17 pathway. Furthermore, lycopene supplementation in high-fat diet increases Glutaredoxin (Glrx) gene and protein expression in the placenta (p < 0.05), increases Glutathione peroxidase (GSH-Px) and Total antioxidant capacity (T-AOC) levels (p < 0.05), decreases reactive oxygen species (ROS) (p < 0.01) and Hydrogen peroxide (H₂ O₂ ) levels (p < 0.05) in placenta. In addition, lycopene supplementation in high fat diet increases the expression of Lep gene and protein in placenta and increases the level of leptin (p < 0.05). In terms of fetal development, the average fetal weight and fetal litter weight are increased by lycopene compared to high-diet treatment.

Physical activity during pregnancy alters gene expression in neonatal tissue

Reducing the risk of developing chronic disease, such as obesity and type 2 diabetes, is an important component of successful aging. Offspring born to mothers who exercise during pregnancy have improved body composition and metabolic profiles. However, mechanisms to explain this phenomenon are lacking.

Purpose

This study examined whether maternal step counts were correlated with neonatal gene expression markers related to glucose metabolism and adipogenesis.

Methods

Physical activity levels were assessed in women with male neonates via Fitbit Flex® during the second and third trimester of pregnancy. The dartos and epidermal/dermal layers of the foreskin were collected following circumcision in full-term, singleton, neonates (n = 12 dartos and n = 14 dermal). Tissue was homogenized, RNA isolated, and a NanoString code set was run to quantify a panel of genes related to glucose metabolism and adipogenesis.

Results

Twelve genes were correlated to steps per day with a P-value of <0.05. After adjusting for multiple comparisons, six genes remained significantly correlated to steps per day (False Discovery Rate-corrected P-value < 0.10). Notably, glucose transporter 1, adiponectin receptor 1, and CCAAT/enhancer-binding protein alpha and beta were positively correlated with steps per day, while peroxisome proliferator-activated receptor alpha and peroxisome proliferator-activated receptor gamma coactivator 1- alpha were negatively correlated with steps per day.

Conclusion

Maternal physical activity is associated with offspring gene expression markers of adipogenesis, insulin sensitivity and glucose uptake. Future studies should aim to mechanistically examine whether these markers are driving increased adiposity in offspring born to sedentary mothers.

Maternal high fat diet and its consequence on the gut microbiome: A rat model

The biological changes that occur during pregnancy in the female mammal include shifts in hormonal regulation in preparation for parturition and lactation, and changes in energy metabolism. In women, studies have also shown that during pregnancy there is a reduction in bacterial species richness in the gut. In the current experiment rats were used to model the interaction of diet, reproductive status, and intestinal bacterial microbiota during pregnancy and lactation. In Experiment 1 rats were exposed to either standard chow or high-fat chow (60%) and were divided into two groups: unmated (NULL) or mated (RE). In Experiment 2, both NULL and RE rats were exposed to high-fat chow for a 30-day period. High-throughput sequencing of the 16S rRNA gene revealed that pregnancy impacted the gut microbiota in a similar manner to humans. The impact of reproductive status on microbiota composition, however, was stronger in rats fed a high-fat (HF) diet. Diet-induced changes replicated some of the changes observed in humans, such as increasing the Firmicutes/Bacteroidetes ratio. However, in contrast to humans, pregnancy in rats did not increase β-diversity between microbiota from different animals. These results indicate that during pregnancy in rats, the gut microbiota is altered in a similar manner to that which occurs in women, and that these changes are further exaggerated by exposure to a HF diet. Thus, the rat may allow modelling the effects of consumption of HF food during pregnancy and enable future studies to determine the risks of HF diets during pregnancy and its consequences on the offspring.

High-fat feeding during pregnancy and lactation affects offspring metabolism in rats

This study was designed to examine the interaction of pregnancy and dietary fat on pregnancy outcome and offspring metabolism in rats. Wistar rats were divided into four groups: HF (40% fat by weight) feeding and pregnant (HFP, n = 15); HF nonpregnant control (HFNP, n = 10); control diet (4.5% fat) and pregnant (CHP, n = 12); and control diet nonpregnant (CHNP, n = 10). Rats were fed the same diets throughout gestation and lactation and were sacrificed at weaning. Litter size was kept at six pups with extra pups killed at birth. HF-fed dams had significantly less caloric intake than control counterparts. HFP had similar body weight changes as CHP during gestation and lactation, whereas HFNP had significantly higher weight and fat content than CHNP. There was no difference in pup's birth weight. However, significantly more HF dams cannibalized their pups. Newborns delivered to HF-fed dams had higher insulin/glucose ratios than CH pups. HFP weanlings weighed more, had more body fat (%), higher liver weight, liver lipid content, and higher blood glucose and triglyceride levels than CHP weanlings. The long-term effects of these metabolic abnormalities need to be further examined.

The role of the glucose/fatty acid cycle in the selective modulation of non-oxidative and oxidative glucose disposal by oxidative muscle in late pregnancy

Physiological insulin stimulation (induced by re-feeding) in late (19 to 20 days) pregnancy in the rat led to only partial reversal of starvation-induced increases in circulating fatty acid concentrations. The impaired suppression of adipose tissue lipolysis was associated with a clear attenuation of the activation of PDHa activity in oxidative skeletal muscles (diaphragm, soleus and adductor longus) in response to physiological insulin stimulation. In contrast, effects of late pregnancy to suppress glucose utilization were only modest in oxidative skeletal muscles, where a predominate fate of glucose under physiological insulin stimulation is glycogen formation. The ability of the pregnant rat to sustain glycogen repletion during physiological insulin stimulation was retained. Glucose utilization by the heart, which in virgin rats is particularly sensitive to increases in lipid-fuel supply and oxidation, bore a significant inverse relationship with the plasma fatty acid concentrations in late-pregnant rats. We conclude that an elevation in circulating fatty acid concentrations in late pregnancy provokes changes in glucose utilization by cardiac and skeletal muscle which are consistent with the operation of the glucose-fatty acid cycle. Importantly, these effects pertain under physiological hyperinsulinaemia. The relative insensitivity of glucose utilization by oxidative skeletal muscle to late pregnancy under conditions of physiological insulin stimulation presumably reflects the predominant use of glucose as a substrate for glycogen synthesis rather than as an energy substrate.

Evaluation of in vivo insulin action and glucose metabolism in milk-fed rats

Milk diet has long been recommended in the management of gastrointestinal pathologies. Since milk feeding represents a high fat-low carbohydrate diet and it is acknowledged that insulin resistance is one of the consequences of high fat feeding, it is important to know whether or not chronic milk feeding leads to an impairment of the insulin-mediated glucose metabolism. To examine this question, adult female rats were given raw cow's milk (50% of total calories as lipids) for 18 days. They were compared to rats raised in parallel and fed the standard laboratory diet (15% of total calories as lipids). At the end of the 18 day period, body weight, daily caloric intake, basal plasma glucose and insulin levels in the milk-fed rats were similar to those in the control rats. In vivo insulin action was assessed with the euglycemichyperinsulinemic clamp technique in anesthetized animals. These studies were coupled with the 2-deoxyglucose technique allowing a measurement of glucose utilization by individual tissues. In the milk fed rats: 1) the basal rate of endogenous glucose production was significantly (p < 0.01) reduced (by 20%); 2) their hepatic glucose production was however normally suppressed by hyperinsulinemia; 3) their basal glucose utilization rate was significantly (p < 0.01) reduced (by 20%); 4) their glucose utilization rate by the whole-body mass or by individual tissues was normally increased by hyperinsulinemia. These results indicate that insulin action in adult rats is not grossly altered after chronic milk-feeding, at least under the present experimental conditions.

Maternal alcohol ingestion inhibits fetal glucose uptake and growth

The distribution of maternally-derived glucose was determined in selected tissues of fetuses from ethanol-fed (EF) rats and from pair-fed (PF) and ad lib-fed (AF) controls. Maternal ethanol ingestion resulted in reduced fetal brain and liver weights and lower liver and lung glycogen levels compared to those of the PF or AF control groups. In addition, experimental fetuses exhibited reduced uptake of maternally-derived [3H] 2-deoxy-D-glucose (2-DG) by placenta and fetal brain. Fetal body, liver, lung, and brain weights correlated with fetal plasma 3H activity and with the fetal:maternal plasma 3H ratio, an indicator of the rate of placental glucose transfer. Brain weight correlated with 2-DG content per gram tissue weight. These observations suggest that reduced nutrient availability due to impaired placental transfer plays a role in the intrauterine growth retardation associated with maternal ethanol ingestion.