Nutritional programming of insulin resistance: causes and consequences

HM-chromanone alleviates hyperglycemia and inflammation in mice with endotoxin-induced insulin resistance

This study was designed to investigate whether (E)-5-hydroxy-7-methoxy-3-(2'-hydroxybenzyl)-4-chromanone alleviates inflammation and hyperglycemia in mice with endotoxin-induced insulin resistance. (E)-5-hydroxy-7-methoxy-3-(2'-hydroxybenzyl)-4-chromanone (10, 30, and 50 mg/kg bodyweight) was orally pre-administered to C57BL/6 J mice. An hour later, lipopolysaccharides (20 mg/kg bodyweight) was administered intraperitoneally to induce endotoxins. Blood samples were collected from the tail vein of the mice every 0, 30, and 90 min. The results indicated that (E)-5-hydroxy-7-methoxy-3-(2'-hydroxybenzyl)-4-chromanone effectively regulated blood glucose levels in mice with endotoxin-induced insulin resistance. Furthermore, (E)-5-hydroxy-7-methoxy-3-(2'-hydroxybenzyl)-4-chromanone significantly reduced the phosphorylation of mammalian target of rapamycin, ribosomal protein S6 kinase 1, and protein kinase C θ. Additionally, (E)-5-hydroxy-7-methoxy-3-(2'-hydroxybenzyl)-4-chromanone suppressed the phosphorylation of c-Jun-NH2-terminal kinase and IkB kinase β, thereby decreasing the phosphorylation of inhibitor of nuclear factor kappa-B α and activating the nuclear factor-κB and activator protein-1 in the liver. Therefore, the expression of tumor necrosis factor-α, interleukin-6, and interleukin-1β was significantly reduced by suppressing the nuclear factor-κB and activator protein 1 activity. Suppression of mammalian target of rapamycin, S6 kinase 1, protein kinase C θ, c-Jun-NH2-terminal kinase, and IkB kinase β also ameliorated insulin resistance by reducing the phosphorylation of insulin receptor substrate-1 serine 307, thereby decreasing hyperglycemia. These findings suggest that (E)-5-hydroxy-7-methoxy-3-(2'-hydroxybenzyl)-4-chromanone can alleviate hyperglycemia and inflammation in mice with endotoxin-induced insulin resistance.

Long-term effects of prenatal undernutrition on female rat hypothalamic KNDy neurons

The nutritional environment during development periods induces metabolic programming, leading to metabolic disorders and detrimental influences on human reproductive health. This study aimed to determine the long-term adverse effect of intrauterine malnutrition on the reproductive center kisspeptin-neurokinin B-dynorphin A (KNDy) neurons in the hypothalamic arcuate nucleus (ARC) of female offspring. Twelve pregnant rats were divided into ad-lib-fed (control, n = 6) and 50% undernutrition (UN, n = 6) groups. The UN group was restricted to 50% daily food intake of the control dams from gestation day 9 until term delivery. Differences between the two groups in terms of various maternal parameters, including body weight (BW), pregnancy duration, and litter size, as well as birth weight, puberty onset, estrous cyclicity, pulsatile luteinizing hormone (LH) secretion, and hypothalamic gene expression of offspring, were determined. Female offspring of UN dams exhibited low BW from birth to 3 weeks, whereas UN offspring showed signs of precocious puberty; hypothalamic Tac3 (a neurokinin B gene) expression was increased in prepubertal UN offspring, and the BW at the virginal opening was lower in UN offspring than that in the control group. Interestingly, the UN offspring showed significant decreases in the number of KNDy gene-expressing cells after 29 weeks of age, but the number of ARC kisspeptin-immunoreactive cells, pulsatile LH secretions, and estrous cyclicity were comparable between the groups. In conclusion, intrauterine undernutrition induced various changes in KNDy gene expression depending on the life stage. Thus, intrauterine undernutrition affected hypothalamic developmental programming in female rats.

Early unhealthy eating habits underlie morpho-functional changes in the liver and adipose tissue in male rats

Early-life consumption of high-fat and sugar-rich foods is recognized as a major contributor for the onset of metabolic dysfunction and its related disorders, including diabetes and nonalcoholic fatty liver disease. The lifelong impact of early unhealthy eating habits that start at younger ages remains unclear. Therefore, to better understand the effects of diet, it is essential to evaluate the structural and functional changes induced in metabolic organs and potential mechanisms underlying those changes. To investigate the long-term effects of eating habits, young male rats were exposed to high-sugar and high-energy diets. After 14 weeks, body composition was assessed, and histopathological changes were analyzed in the liver and adipose tissue. Serum biochemical parameters were also determined. Expression of inflammatory markers in the liver was evaluated by immunohistochemistry. Our results revealed that serum levels of glucose, creatinine, aspartate transaminase (AST), alanine transaminase (ALT), and lipid profile were increased in rats red high-sugar and high-energy diets. Histopathological alterations were observed, including abnormal hepatocyte organization and lipid droplet accumulation in the liver, and abnormal structure of adipocytes. In both unhealthy diet groups, hepatic expression of Toll-like receptor 4 (TLR4), cyclooxygenase 2 (COX-2), and E-selectin were increased, as well as a biomarker of oxidative stress. Together, our data demonstrated that unhealthy diets induced functional and structural changes in the metabolic organs, suggesting that proinflammatory and oxidative stress mechanisms trigger the hepatic alterations and metabolic dysfunction.

Curcumin alleviates hepatic steatosis by improving mitochondrial function in postnatal overfed rats and fatty L02 cells through the SIRT3 pathway

Postnatal overfeeding could increase the risk of non-alcoholic fatty liver disease (NAFLD) in adulthood. This study investigated the effects of curcumin (CUR) on hepatic steatosis in postnatal overfed rats and elucidated potential mechanisms in mitochondrial functions. Male rats were adjusted to ten (normal litter, NL) or three (small litter, SL) at postnatal day 3. After weaning, NL rats were fed with normal diet (NL) or a high-fat diet (NH) for 10 weeks. SL rats were fed with normal diet (SL), a high-fat diet (SH), a normal diet supplemented with 2% CUR (SL-CUR) or a high-fat diet supplemented with 2% CUR (SH-CUR). At week 13, compared with NL rats, SL and NH rats showed increased body weight, glucose intolerance, dyslipidemia and hepatic lipid accumulation, and these changes were more obvious in SH rats. The opposite trends were observed in SL-CUR and SH-CUR rats. Moreover, CUR could preserve mitochondrial biogenesis and antioxidant response in postnatal overfed rats, and upregulated the mRNA and protein levels of SIRT3. In vitro, L02 cells were exposed to free fatty acids and/or CUR. CUR decreased the levels of cellular lipids and mitochondrial reactive oxygen species, and increased the mitochondrial DNA copy number and superoxide dismutase activity in fatty L02 cells. However, these effects were blocked after SIRT3 silencing. It was concluded that postnatal overfeeding damaged mitochondrial biogenesis and antioxidant response, and increased hepatic lipids and the severity of high-fat-induced NAFLD, while CUR alleviated hepatic steatosis, at least partially, by enhancing mitochondrial function through SIRT3.

Role of stilbenes against insulin resistance: A review

Insulin resistance (IR) is a state characterized by the inability of tissues to utilize blood glucose particularly liver, muscle, and adipose tissues resulting in hyperglycemia and hyperinsulinemia. A close relationship exists between IR and the development of type 2 diabetes (T2D). Therefore, therapeutic approaches to treat IR also improve T2D simultaneously. Scientific evidence has highlighted the major role of inflammatory cytokines, reactive oxygen species (ROS), environmental & genetic factors, and auto-immune disorders in the pathophysiology of IR. Among therapeutic remedies, nutraceuticals like polyphenols are being used widely to ameliorate IR due to their safer nature compared to pharmaceutics. Stilbenes are considered important metabolically active polyphenols currently under the limelight of research to cope with IR. In this review, efforts are made to elucidate cellular and subcellular mechanisms influenced by stilbenes including modulating insulin signaling cascade, correcting glucose transport pathways, lowering postprandial glucose levels, and protecting β-cell damage and its effects on the hyperactive immune system and proinflammatory cytokines to attenuate IR. Furthermore, future directions to further the research in stilbenes as a strong candidate against IR are included so that concrete recommendation for their use in humans is made.

Understanding the Long-Lasting Effects of Fetal Nutrient Restriction versus Exposure to an Obesogenic Diet on Islet-Cell Mass and Function

Early life represents a window of phenotypic plasticity. Thus, exposure of the developing fetus to a compromised nutritional environment can have long term consequences for their health. Indeed, undernutrition or maternal intake of an obesogenic diet during pregnancy leads to a heightened risk of type 2 diabetes (T2D) and obesity in her offspring in adult life. Given that abnormalities in beta-cell function are crucial in delineating the risk of T2D, studies have investigated the impact of these exposures on islet morphology and beta-cell function in the offspring in a bid to understand why they are more at risk of T2D. Interestingly, despite the contrasting maternal metabolic phenotype and, therefore, intrauterine environment associated with undernutrition versus high-fat feeding, there are a number of similarities in the genes/biological pathways that are disrupted in offspring islets leading to changes in function. Looking to the future, it will be important to define the exact mechanisms involved in mediating changes in the gene expression landscape in islet cells to determine whether the road to T2D development is the same or different in those exposed to different ends of the nutritional spectrum.

Lasting Effects of Low to Non-Lethal Radiation Exposure during Late Gestation on Offspring's Cardiac Metabolism and Oxidative Stress

Ionizing radiation (IR) is known to cause fetal programming, but the physiological effects of low-dose IR are not fully understood. This study examined the effect of low (50 mGy) to non-lethal (300 and 1000 mGy) radiation exposure during late gestation on cardiac metabolism and oxidative stress in adult offspring. Pregnant C57BL/6J mice were exposed to 50, 300, or 1000 mGy of gamma radiation or Sham irradiation on gestational day 15. Sixteen weeks after birth, ¹⁸F-Fluorodeoxyglucose (FDG) uptake was examined in the offspring using Positron Emission Tomography imaging. Western blot was used to determine changes in oxidative stress, antioxidants, and insulin signaling related proteins. Male and female offspring from irradiated dams had lower body weights when compared to the Sham. 1000 mGy female offspring demonstrated a significant increase in ¹⁸F-FDG uptake, glycogen content, and oxidative stress. 300 and 1000 mGy female mice exhibited increased superoxide dismutase activity, decreased glutathione peroxidase activity, and decreased reduced/oxidized glutathione ratio. We conclude that non-lethal radiation during late gestation can alter glucose uptake and increase oxidative stress in female offspring. These data provide evidence that low doses of IR during the third trimester are not harmful but higher, non-lethal doses can alter cardiac metabolism later in life and sex may have a role in fetal programming.

Placental superoxide dismutase 3 mediates benefits of maternal exercise on offspring health

Poor maternal diet increases the risk of obesity and type 2 diabetes in offspring, adding to the ever-increasing prevalence of these diseases. In contrast, we find that maternal exercise improves the metabolic health of offspring, and here, we demonstrate that this occurs through a vitamin D receptor-mediated increase in placental superoxide dismutase 3 (SOD3) expression and secretion. SOD3 activates an AMPK/TET signaling axis in fetal offspring liver, resulting in DNA demethylation at the promoters of glucose metabolic genes, enhancing liver function, and improving glucose tolerance. In humans, SOD3 is upregulated in serum and placenta from physically active pregnant women. The discovery of maternal exercise-induced cross talk between placenta-derived SOD3 and offspring liver provides a central mechanism for improved offspring metabolic health. These findings may lead to novel therapeutic approaches to limit the transmission of metabolic disease to the next generation.

Using a Microsimulation of Energy Balance to Explore the Influence of Prenatal Sugar-Sweetened Beverage Intake on Child BMI

OBJECTIVE

Experiments with animals suggest that high sugar consumption during pregnancy may predispose offspring to obesity, but few human studies have examined this relationship. This study explored the association between the consumption of sugar-sweetened beverages (SSBs) during pregnancy and caloric intake through childhood.

METHODS

Using cohort data on child weight, height, and physical activity levels, a lab-validated microsimulation model of energy balance was employed to infer the caloric intake of children through age 11 years. Random effects models were then employed to explore the relationships between prenatal maternal consumption and inferred caloric intake during childhood.

RESULTS

An additional daily serving of SSBs during the second trimester of pregnancy was associated with an increase in child consumption of 13 kcal/d (95% CI: 1.2-26.8). Age-stratified models adjusting for maternal and child covariates suggested that this association was strongest for children aged 2.5 to 5.5 years. The consumption of SSBs during the first trimester was not found to have a consistently positive relationship to caloric intake.

CONCLUSIONS

These findings suggest that SSB consumption during the second trimester of pregnancy is associated with child energy intake and may influence anthropometry in early childhood, which is consistent with and suggestive of the presence of biological causal pathways alongside likely simultaneous contributions of social and environmental influences.

Possible Dietary Effects of Insect-Based Diets across Zebrafish (Danio rerio) Generations: A Multidisciplinary Study on the Larval Phase

Insects represent a valuable and sustainable alternative ingredient for aquafeed formulation. However, insect-based diets have often highlighted controversial results in different fish species, especially when high inclusion levels were used. Several studies have demonstrated that nutritional programming through parental feeding may allow the production of fish better adapted to use sub-optimal aquafeed ingredients. To date, this approach has never been explored on insect-based diets. In the present study, five experimental diets characterized by increasing fish meal substitution levels with full-fat Black Soldier Fly (Hermetia illucens; BSF) prepupae meal (0%, 25%, 50%, 75% and 100%) were used to investigate the effects of programming via broodstock nutrition on F1 zebrafish larvae development. The responses of offspring were assayed through biometric, gas chromatographic, histological, and molecular analyses. The results evidenced that the same BSF-based diets provided to adults were able to affect F1 zebrafish larvae fatty acid composition without impairing growth performances, hepatic lipid accumulation and gut health. Groups challenged with higher BSF inclusion with respect to fish meal (50%, 75% and 100%) showed a significant downregulation of stress response markers and a positive modulation of inflammatory cytokines gene expression. The present study evidences that nutritional programming through parental feeding may make it possible to extend the fish meal substitution level with BSF prepupae meal in the diet up to almost 100% without incurring the well-known negative side effects of BSF-based diets.

Increasing preweaning milk replacer supply affects postweaning energy metabolism of Holstein male calves

Male Holstein calves commonly receive minimal quantities of milk replacer (MR) to speed up weaning and reduce costs. Studies with Holstein female calves show that early life feed restriction affects energy metabolism later in life. Aiming to test this hypothesis, 120 Holstein bull calves (48.4 ± 2.2 kg of BW and 20 ± 3.2 d of age) housed in 24 pens were blocked and randomized to two treatments: A low calf MR allowance (LP) (two daily doses of 2 l each, 582 g/d of DM), or a high MR allowance (HP) (two daily meals of 4 l each, 1164 g/d of DM). Calves were weaned at day 49 of the study and slaughtered at 32.8 ± 0.5 weeks of age. Throughout the study, animals had ad libitum access to a common compound feed, straw, and water. Twenty-four animals were randomly selected for an intravenous glucose tolerance test (IVGTT). The IVGTT was performed at week 6 and 12 of the study and consisted of an intravenous glucose infusion and sequential blood sampling up to 90 min after glucose infusions. Calves were heavier for HP until week 12, after which the difference disappeared. By design, the MR intake was higher in the HP group resulting in a higher energy intake and a higher average daily gain in the preweaning phase. Blood glucose curves were not different at week 6, but at week 12, 5 min after the infusion, glucose was higher in HP calves. Insulin curves were not different at week 6. Nevertheless, in week 12, a higher insulin concentration was observed for HP 5, 10, 15, 20, 30, 35, and 45 min' postinfusion, indicating a higher requirement of insulin to control glycemia. Differences between HP and LP calves were also observed for the quantitative insulin sensitivity check index, maximum insulin concentration, and insulin delta at week 12. Blood glucose reached maximum concentration within 5-10 min of the IVGTT test, and the concentration was, on average, 8.58 and 10.80 mmol/l at weeks 6 and 12, respectively. Insulin reached maximum concentration within 10-15 min of the IVGTT, and concentrations were, on average, 33.32 and 32.61 μUI/ml at weeks 6 and 12, respectively. Doubling MR supply improved animal growth up to weaning, but these differences disappeared by the end of the feeding period. Despite similar responses to glucose infusions preweaning, higher milk supply seemed to decrease insulin sensitivity after weaning.

Moderate over-feeding of different sources of metabolizable energy and protein improved gestational insulin resistance markers and maternal metabolic status of sheep around lambing

The objective of this study was to determine the effect of moderate over-nutrition of energy (using flaxseed as a source of n-3 fatty acids) and protein (using rumen-protected lysine and methionine) around parturition on prepartal insulin resistance (IR) and periparturient metabolic status and performance of ewes. For this purpose, 32 apparently healthy ewes (2.5 ± 1 years old, 42.19 ± 1.65 kg body weight (BW)) were randomly selected out of 200 pregnant Zell ewes on d 50 before the expected lambing. After receiving a ten-day adaptation diet, eight ewes were randomly allocated to one of the following four dietary treatments: 1) the adaptation diet that meets the metabolizable energy (ME) and protein (MP) requirements of ewes during late pregnancy as recommended by National Research Council = NRC (2007) (Control = CON). 2) A diet with 10% higher levels of ME than NRC (2007) recommendations using corn grain as a source of extra ME (HEC). 3) A diet with 10% higher levels of ME compared to NRC (2007) recommendations using flaxseed for additional ME (HEF). 4) A diet with a 10% higher level of MP than NRC (2007) recommendations using rumen-protected lysine and methionine as a source of extra MP (PRO). While the dietary treatments did not affect animals' dry matter intake (DMI), the CON ewes lost more BW starting from d 10 to d 30 relative to parturition compared to others (P < 0.05). Milk protein and fat yield (g/d) were significantly higher for PRO and HEF compared to HEC and CON ewes (P < 0.05). Moderately over-fed ewes with MP and ME had an improved insulin sensitivity (IS) compared to CON ones. The source of additional ME also impacted IR indices because HEC showed an enhancement in IS than HEF animals (P < 0.05). A lower IS in CON ewes was parallel with higher concentrations of plasma urea at prepartum (P < 0.01), lower levels of plasma cholesterol, triglyceride (P < 0.01) and glucose post-partum (P < 0.05), and a tendency for higher levels of beta-hydroxybutyrate (BHB) and non-esterified fatty acids (NEFA) in CON ewes during both pre- and post-partum periods. There were negative correlations between plasma urea, BHB, and NEFA with IR markers on d 7 prepartum in line with these results. Comparing data, we could not find a significant change in metabolic status among ewes fed with either PRO or HEF/HEC. In conclusion, the inclusion of 10% extra MP and ME could improve late gestation maternal IS and the metabolic status of dams around lambing.

Hyperlipidic diet affects body composition and induces anxiety-like behaviour in intrauterine growth-restricted adult mice

NEW FINDINGS

What is the central question of this study? What is the effect in male and female offspring of a protein-deficient diet producing intrauterine growth restriction (IUGR) in maternal mice on morphometric, metabolic and behavioural parameters before and after a challenge with a fat diet? What is the main finding and its importance? Male and female mice presented different growth trajectories after birth. IUGR favoured increased adiposity in male mice, and high-fat diet-induced anxiety-like behaviour in female mice.

ABSTRACT

As there is sexual dimorphism in the response to maternal manipulations, we aimed to analyse the effects of intrauterine growth restriction (IUGR) in both sexes on morphometric, metabolic and behavioural parameters throughout postnatal development, and after challenge with a hyperlipidic diet. Female Swiss mice (n = 59) were distributed into two groups (SD: standard diet, n = 26; and PDD: isocaloric protein-deficient diet, n = 33), 2 weeks before mating and during the gestational period. After birth, offspring from SD and PDD dams were cross-fostered and nurtured by SD dams until postnatal day (PND) 28. At PND 60 all animals were challenged with a hypercaloric diet for 4 weeks. Offspring birth weight was significantly reduced in the PDD group compared to the SD group (P = 0.0001), but only male offspring presented a rapid catch-up during the first 21 days of development. Although no differences in body weight were observed between groups after the challenge with the hyperlipidic diet, an increase in the relative perigonadal white adipose tissue (P = 0.009) and a decrease in gross gastrocnemius muscle weight (P = 0.010) were observed in the PDD males. In relation to behavioural tests, there was an increase in locomotion in both sexes (P = 0.0001), and a decrease in female grooming (P = 0.006) in the PDD group. Additionally, females from the PDD group showed increased hyperlipidic food intake. In conclusion, IUGR affected both sexes, with females showing prominent behavioural modifications and males presenting altered body composition elicited by a hyperlipidic diet.

Vitamin D Deficiency in Mexican Pregnant Women: Is Supplementation with ≤400 IU/day Enough?

Controversy remains surrounding vitamin D routine supplementation in healthy pregnancy, and the doses are unclear. The aim of this study was to describe maternal vitamin D status throughout pregnancy in a group of Mexican women and evaluate the effect of frequently prescribed doses of vitamin D3 on longitudinal 25-OH-D concentrations, adjusting for obesity, season, and other factors. We conducted a cohort study (Instituto Nacional de Perinatología-INPer) (2017-2020)) of healthy pregnant women without complications. Pregestational overweight/obesity (body mass index ≥ 25), vitamin D3 supplementation (prescribed by physician; 0-250, 250-400, and >400 IU/day), and serum 25-OH-D concentrations (ELISA) were evaluated in each trimester of pregnancy. Vitamin D deficiency or insufficiency was computed (<20 and <30 ng/mL, respectively). We studied 141 adult women; 58.5% had pregestational obesity or overweight. In the first trimester, 45.8% of the women were supplemented with vitamin D3; 51.4% had vitamin D insufficiency and 37.3%, deficiency. In the third trimester, 75.4% of the women were supplemented, and 20% of them still had deficiency. The final general mixed linear model showed that 25-OH-D significantly increased throughout pregnancy (p < 0.001); the highest increase was observed in the third trimester in women with doses >400 IU/day of vitamin D3 (+4 ng/mL, 95% CI: 1.72-8.11 ng/mL). In winter/autumn, 25-OH-D concentrations were also lower (p ≤ 0.05). In this group of pregnant Mexican women, the prevalence of vitamin D deficiency and insufficiency was high. A higher increase in 25-OH-D concentrations during pregnancy was observed when the women were supplemented with >400 IU/day. Common supplementation doses of 250-400 IU/day were insufficient for achieving an adequate maternal vitamin D status.

Parental Selenium Nutrition Affects the One-Carbon Metabolism and the Hepatic DNA Methylation Pattern of Rainbow Trout (Oncorhynchus mykiss) in the Progeny

Selenium is an essential micronutrient and its metabolism is closely linked to the methionine cycle and transsulfuration pathway. The present study evaluated the effect of two different selenium supplements in the diet of rainbow trout (Onchorhynchus mykiss) broodstock on the one-carbon metabolism and the hepatic DNA methylation pattern in the progeny. Offspring of three parental groups of rainbow trout, fed either a control diet (NC, basal Se level: 0.3 mg/kg) or a diet supplemented with sodium selenite (SS, 0.8 mg Se/kg) or hydroxy-selenomethionine (SO, 0.7 mg Se/kg), were collected at swim-up fry stage. Our findings suggest that parental selenium nutrition impacted the methionine cycle with lower free methionine and S-adenosylmethionine (SAM) and higher methionine synthase (mtr) mRNA levels in both selenium-supplemented treatments. DNA methylation profiling by reduced representation bisulfite sequencing (RRBS) identified differentially methylated cytosines (DMCs) in offspring livers. These DMCs were related to 6535 differentially methylated genes in SS:NC, 6890 in SO:NC and 7428 in SO:SS, respectively. Genes with the highest methylation difference relate, among others, to the neuronal or signal transmitting and immune system which represent potential targets for future studies.

Developmental programming of insulin resistance: are androgens the culprits?

Insulin resistance is a common feature of many metabolic disorders. The dramatic rise in the incidence of insulin resistance over the past decade has enhanced focus on its developmental origins. Since various developmental insults ranging from maternal disease, stress, over/undernutrition, and exposure to environmental chemicals can all program the development of insulin resistance, common mechanisms may be involved. This review discusses the possibility that increases in maternal androgens associated with these various insults are key mediators in programming insulin resistance. Additionally, the intermediaries through which androgens misprogram tissue insulin sensitivity, such as changes in inflammatory, oxidative, and lipotoxic states, epigenetic, gut microbiome and insulin, as well as data gaps to be filled are also discussed.

Epigenome environment interactions accelerate epigenomic aging and unlock metabolically restricted epigenetic reprogramming in adulthood

Our early-life environment has a profound influence on developing organs that impacts metabolic function and determines disease susceptibility across the life-course. Using a rat model for exposure to an endocrine disrupting chemical (EDC), we show that early-life chemical exposure causes metabolic dysfunction in adulthood and reprograms histone marks in the developing liver to accelerate acquisition of an adult epigenomic signature. This epigenomic reprogramming persists long after the initial exposure, but many reprogrammed genes remain transcriptionally silent with their impact on metabolism not revealed until a later life exposure to a Western-style diet. Diet-dependent metabolic disruption was largely driven by reprogramming of the Early Growth Response 1 (EGR1) transcriptome and production of metabolites in pathways linked to cholesterol, lipid and one-carbon metabolism. These findings demonstrate the importance of epigenome:environment interactions, which early in life accelerate epigenomic aging, and later in adulthood unlock metabolically restricted epigenetic reprogramming to drive metabolic dysfunction.

Early life exposure to environmental stressors, including endocrine disrupting chemicals (EDCs), can impact health later in life. Here, the authors show that neonatal EDC exposure in rats causes epigenetic reprogramming in the liver, which is transcriptionally silent until animals are placed on a Western-style diet.

Aluminum Exposure and Gestational Diabetes Mellitus: Associations and Potential Mediation by n-6 Polyunsaturated Fatty Acids

As the earth's third most abundant element with various industrial applications, aluminum (Al) has received increasing concerns over its potential adverse health effects. Although Al exposure has been suggested to increase the risks of type 2 diabetes, little has been done to explore Al exposure in pregnant women and potential impact on the incidence of gestational diabetes mellitus (GDM). Our present study demonstrated positive associations between Al concentrations in maternal plasma collected in the first trimester of pregnancy and GDM risks (P_trend < 0.001) based on a nested case-control study from Wuhan, China, including 305 GDM cases and 305 healthy controls. The highest tertile of plasma Al concentrations corresponded to an odds ratio of 4.03 (95% confidence interval: [2.14, 7.58]) relative to the lowest tertile, after the adjustment for established GDM risk factors and other plasma metals. We also observed significant correlations between plasma Al and several plasma polyunsaturated fatty acids (PUFA; e.g., linoleic acid 18:2 n-6) levels. In addition, mediation effects on the associations of Al exposure with GDM risks were observed for n-6 PUFAs (estimated mediation percentage: 48.3%) and total PUFAs (48.9%). Our study is not only by far the largest study of its kind to demonstrate maternal Al exposure and the association with GDM risks, but it also offers an insight into the potential mediation roles of n-6 PUFAs in an epidemiological setting. These findings contribute to a better understanding of perinatal Al exposure and GDM risks.

Long-term impact of a 4-day feed restriction at the protozoea stage on metabolic gene expressions of whiteleg shrimp (Litopenaeus vannamei)

Based on the "nutritional programming" concept, we evaluated the long-term effects of an early four-day caloric restriction (40% reduction in feed allowance compared to a normal feeding level) at the protozoea stage in whiteleg shrimp. We analyzed long-term programming of shrimp by studying metabolism at the molecular level, through RT-qPCR of key biomarkers (involved in intermediary metabolism and digestion). The mRNA levels (extracted from the whole body) were analyzed after the stimulus and after the rearing period, at 20 and 35 days, respectively. At the end of the experimental period, shrimp growth performance was evaluated. There was no difference between normal feed allowance (CTL) and feed-restricted shrimp (RES) for performance parameters (survival, final body weight and the number of post-larvae g-1 or PL g-1). The stimulus directly affected the mRNA levels for only two genes, i.e., preamylase and lvglut 2 which were expressed at higher levels in feed-restricted shrimp. In the long-term, higher levels of mRNAs for enzymes coding for glycolysis and ATP synthesis were also detected. This suggests a possible long-term modification of the metabolism that is linked to the stimulus at the protozoea stage. Overall, further studies are needed to improve nutritional programming in shrimp.

Early life programming in mice by maternal overnutrition: mechanistic insights and interventional approaches

Animal models have been indispensable in elucidating the potential causative mechanisms underlying the effects of maternal diet on offspring health. Of these, the mouse has been widely used to model maternal overnutrition and/or maternal obesity and to study its effects across one or more generations. This review discusses recent findings from mouse models, which resemble the human situation, i.e. overnutrition/obesity across pregnancy and lactation. It also highlights the importance of embryo transfer models in identifying critical developmental period(s) during which specific metabolic changes are programmed in the offspring. The mouse is also an excellent tool for maternal intervention studies aimed at elucidating the longer-term effects on the offspring and for defining possible maternal factors underling the programming of metabolic adversity in offspring. While knowledge of the mouse genome and the molecular tools available have allowed great progress to be made in the field, it is clear that we need to define if the effects on the offspring are mediated by maternal obesity per se or if specific components of the maternal metabolic environment are more important. We can then begin to identify at-risk offspring and to design more effective interventions for the mother and/or her child. This article is part of the theme issue 'Developing differences: early-life effects and evolutionary medicine'.

How Birth Season Affects Vulnerability to the Effect of Ambient Ozone Exposure on the Disease Burden of Hypertension in the Elderly Population in a Coastal City in South China

Birth season is an important factor that reflects prenatal nutritional conditions during early development, and which might have lifelong impacts on health. Moreover, ambient ozone pollution has been considered an important environmental risk factor for hypertension. However, whether birth season affects vulnerability to the effect of ambient ozone exposure on late-life hypertension is still unknown. A flexible case–crossover design was used to explore the effect of ambient ozone exposure on the disease burden of hypertension using years of life lost (YLL) in the elderly population in a coastal city in South China from 2013 to 2016. The influence of birth season was also explored. Ozone exposure was significantly associated with increased YLL from hypertension. The association was higher in the elderly individuals who were born in autumn than in those born in other seasons. Specifically, every 10 μg/m³ increase in ozone was associated with 0.68 (95% CI: 0.27, 1.10) YLL from hypertension in the elderly population born in autumn, while nonsignificant associations were found for those born in other seasons. The birth season, which affects the nutritional condition during early development, could affect vulnerability to the effect of ambient ozone exposure on the disease burden of hypertension in late life. The findings highlighted the importance of taking birth season into consideration when exploring the hypertensive effects of ozone exposure.

Kukoamine B Ameliorate Insulin Resistance, Oxidative Stress, Inflammation and Other Metabolic Abnormalities in High-Fat/High-Fructose-Fed Rats

BACKGROUND

Obesity is characterized by excessive body fat, insulin resistance and dyslipidemia, which increases the chances of developing chronic diseases like type 2 diabetes, cardiovascular diseases, hypertension, nonalcoholic fatty liver diseases, some types of cancers and neurodegenerative diseases. Kukoamine B (Kuk B) is a spermine alkaloid obtained from Lycium chinense, and it has been shown to possess antidiabetic, antioxidant and anti-inflammatory properties. In this study, we evaluated the therapeutic effect of Kuk B on high-fat diet/high-fructose (HFDFr)-induced insulin resistance and obesity in experimental rats.

MATERIALS AND METHODS

Rats were fed with either normal rat diet or HFDFr for 10 consecutive weeks. The groups that were fed with HFDFr received Kuk B (25 and 50 mg/kg) from the beginning of the 6th week to the 10th week. After treatment, the effect of Kuk B on body weight, food, water intake, insulin, blood glucose, serum biochemical parameters, hepatic oxidative stress (malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px) and proinflammatory cytokine (interleukin (IL)-6, interleukin (IL)-1β and tumor necrosis factor alpha (TNF-α)) levels was determined. Histopathological analysis of the liver tissues was also performed.

RESULTS

HFDFr-fed rats showed a significant increase in body weight, fasting blood glucose, insulin, lipid accumulation and liver function enzymes. In addition, HFDFr diet increased hepatic MDA, TNF-α, IL-1β and IL-6 and decreased hepatic SOD, CAT and GSH-Px activities. On the other hand, Kuk B significantly attenuated body weight, insulin resistance, lipid accumulation, oxidative stress and inflammation.

CONCLUSION

These results indicated that Kuk B showed protective effect against HFDFr-induced metabolic disorders by downregulating lipid accumulation, oxidative stress and inflammatory factors.

Role of c-Jun N-Terminal Kinases (JNKs) in Epilepsy and Metabolic Cognitive Impairment

Previous studies have reported that the regulatory function of the different c-Jun N-terminal kinases isoforms (JNK1, JNK2, and JNK3) play an essential role in neurological disorders, such as epilepsy and metabolic-cognitive alterations. Accordingly, JNKs have emerged as suitable therapeutic strategies. In fact, it has been demonstrated that some unspecific JNK inhibitors exert antidiabetic and neuroprotective effects, albeit they usually show high toxicity or lack therapeutic value. In this sense, natural specific JNK inhibitors, such as Licochalcone A, are promising candidates. Nonetheless, research on the understanding of the role of each of the JNKs remains mandatory in order to progress on the identification of new selective JNK isoform inhibitors. In the present review, a summary on the current gathered data on the role of JNKs in pathology is presented, as well as a discussion on their potential role in pathologies like epilepsy and metabolic-cognitive injury. Moreover, data on the effects of synthetic small molecule inhibitors that modulate JNK-dependent pathways in the brain and peripheral tissues is reviewed.

Altered triglyceride and phospholipid metabolism predates the diagnosis of gestational diabetes in obese pregnancy

Gestational diabetes (GDM), a common pregnancy complication associated with obesity and long-term health risks, is usually diagnosed at approximately 28 weeks of gestation. An understanding of lipid metabolism in women at risk of GDM could contribute to earlier diagnosis and treatment. We tested the hypothesis that altered lipid metabolism at the beginning of the second trimester in obese pregnant women is associated with a diagnosis of GDM. Plasma samples from 831 participants (16-45 years, 15-18 weeks gestation, BMI ≥ 30) from the UPBEAT study of obese pregnant women were used. The lipid, sterol and glyceride fraction was isolated and analysed in a semi-quantitative fashion using direct infusion mass spectrometry. A combination of uni-, multi-variate and multi-variable statistical analyses was used to identify candidate biomarkers in plasma associated with a diagnosis of GDM (early third trimester; IADPSG criteria). Multivariable adjusted analyses showed that participants who later developed GDM had a greater abundance of several triglycerides (48:0, 50:1, 50:2, 51:5, 53:4) and phosphatidylcholine (38:5). In contrast sphingomyelins (32:1, 41:2, 42:3), lyso-phosphatidylcholine (16:0, 18:1), phosphatidylcholines (35:2, 40:7, 40:10), two polyunsaturated triglycerides (46:5, 48:6) and several oxidised triglycerides (48:6, 54:4, 56:4, 58:6) were less abundant. We concluded that both lipid and triglyceride metabolism were altered at least 10 weeks before diagnosis of GDM. Further investigation is required to determine the functional consequences of these differences and the mechanisms by which they arise.

Calorie Restriction in Adulthood Reduces Hepatic Disorders Induced by Transient Postnatal Overfeeding in Mice

Impaired early nutrition influences the risk of developing metabolic disorders in later life. We observed that transient postnatal overfeeding (OF) in mice induces long-term hepatic alterations, characterized by microsteatosis, fibrosis associated with oxidative stress (OS), and stress-induced premature senescence (SIPS). In this study, we investigated whether such changes can be reversed by moderate calorie restriction (CR). C57BL/6 male mice pups were maintained during lactation in litters adjusted to nine pups in the normal feeding (NF) group and three pups in the transient postnatal OF group. At six months of age, adult mice from the NF and OF groups were randomly assigned to an ad libitum diet or CR (daily energy supply reduced by 20%) for one month. In each group, at the age of seven months, analysis of liver structure, liver markers of OS (superoxide anion, antioxidant defenses), and SIPS (lipofuscin, p53, p21, p16, pRb/Rb, Acp53, sirtuin-1) were performed. CR in the OF group reduced microsteatosis, decreased levels of superoxide anion, and increased protein expression of catalase and superoxide dismutase. Moreover, CR decreased lipofuscin staining, p21, p53, Acp53, and p16 but increased pRb/Rb and sirtuin-1 protein expression. CR did not affect the NF group. These results suggest that CR reduces hepatic disorders induced by OF.

Higher glycolytic capacities in muscle of carnivorous rainbow trout juveniles after high dietary carbohydrate stimulus at first feeding

Background

Rainbow trout is a “glucose-intolerant” carnivorous species. Using the metabolic programming strategy, we used early nutritional stimuli in order to modify carbohydrate utilization in trout juveniles.

Method

Fish were fed two diets during the first feeding, namely HP (no carbohydrate / high protein) diet and LP (high carbohydrate / low protein) diet. HP diet was used as the control diet and LP diet as an early stimulus diet. We also used another early stimulus with fish fed HP diet every other day during the first feeding (HP restriction feeding - HPR). After the first-feeding stage (4 weeks), all fish were subsequently subjected to a growth trial with a commercial diet followed by a challenge test with the LP diet (11 weeks). At the end of the first feeding stimulus and of the challenge test, we investigated growth performance, glucose metabolism-related parameters and global DNA C^mCGG methylation in trout.

Results

LP and HPR dietary stimuli have been a success as shown by the direct modifications of growth performance and mRNA levels for glucose metabolism-related genes at the end of first feeding compared to alevins fed the HP diet. At the end of the challenge trial, no variation in growth performance and hepatic metabolism of LP-history and HPR-history in trout juveniles were observed. However, in muscle of trout juvenile subjected to LP diet at the first feeding, we found an up-regulation of mRNA levels of some glucose metabolism (glucose transport and glycolysis)-related genes and an increase of activities of important glycolysis-related enzymes (hexokinase, phosphofructokinase and pyruvate kinase). These observations are associated with a decrease in the content of glycogen compared to fish fed the HP diet. Moreover, global C^mCGG DNA methylation in the muscle of fish with LP history was significantly lower than those fed the HP diet.

Conclusion

Dietary LP stimulus at first feeding could permanently modify glucose metabolism and global C^mCGG DNA methylation level in muscle of trout juveniles, showing that the first feeding stage is efficient for programming the glucose metabolism in fish.

Chronic aerobic exercise improves insulin sensitivity and modulates Nrf2 and NF‑κB/IκBα pathways in the skeletal muscle of rats fed with a high fat diet

The present study aimed to investigate the molecular mechanisms of the ameliorative effects of chronic aerobic exercise on non-alcoholic steatohepatitis (NASH) in rat skeletal muscle. Female Sprague-Dawley rats (n=6–9 per group) were divided into four groups: i) Rats fed with normal chow; ii) exercise rats fed with normal chow + exercise (run on a rotarod for 30 min per day from 9–12 weeks); iii) rats fed with a high-fat diet (HFD); iv) rats fed with an HFD + exercise. All HFD rats were fed with an HFD consisting of 30% fat from fish oil throughout the study for 12 weeks. Exercise decreased the levels of hepatic lipogenic markers carbohydrate-responsive element-binding protein, fat-specific protein 27 and liver X receptor and improved systemic glucose and insulin intolerance in the NASH animal model. The beneficial effects may have been mediated partly via the tripartite motif-containing family protein 72 (TRIM72)/PI3K/Akt/mTOR pathway, accompanied with an upregulation of glucose transporter 4 in the skeletal muscle. The exercise regimen activated the master regulator of antioxidant enzymes, nuclear factor erythroid 2-related factor 2, with upregulation of superoxide dismutase [Cu-Zn] expression and a corresponding decrease in kelch-like ECH-associated protein 1 expression, but failed to decrease the levels of the oxidative marker malondialdehyde in the HFD rat skeletal muscle. Chronic exercise decreased the expression of the inflammation marker NF-κB, followed by a decrease in interleukin-6 and tumor necrosis factor-α levels, as verified by a corresponding increase in the level of NF-κB inhibitor α expression. Exercise may exert its beneficial effects by improving muscle insulin sensitivity via the TRIM72/PI3K/Akt/mTOR pathway, contributing to the improvement of systemic insulin intolerance, and finally leading to decreased hepatic lipogenesis during NASH. The attenuation of insulin resistance by exercise may be partly achieved through a decrease in the level of inflammation and an increased antioxidant response.

Evidence from 3-month-old infants shows that a combination of postnatal feeding and exposures in utero shape lipid metabolism

We tested the hypothesis that both postnatal feeding and conditions in utero affect lipid metabolism in infants. Infants who experienced restrictive growth conditions in utero and others exposed to maternal hyperglycaemia were compared to a control group with respect to feeding mode. Dried blood spots were collected from a pilot subset of infant participants of the Cambridge Baby Growth Study at 3mo. Groups: (a) a normal gestation (control, n = 40), (b) small for gestational age (SGA, n = 34) and (c) whose mothers developed hyperglycaemia (n = 59). These groups were further stratified by feeding mode; breastfed, formula-fed or received a mixed intake. Their phospholipid, glyceride and sterol fractions were profiled using direct infusion mass spectrometry. Statistical tests were used to identify molecular species that indicated differences in lipid metabolism. The abundance of several phospholipids identified by multivariate analysis, PC(34:1), PC(34:2) and PC-O(34:1), was 30-100% higher across all experimental groups. SM(39:1) was around half as abundant in in utero groups among breastfed infants only. The evidence from this pilot study shows that phospholipid metabolism is modulated by both conditions in utero and postnatal feeding in a cohort of 133 Caucasian infants, three months post partum.

Relationship between the lipid composition of maternal plasma and infant plasma through breast milk

INTRODUCTION

This study was motivated by the report that infant development correlates with particular lipids in infant plasma.

OBJECTIVE

The hypothesis was that the abundance of these candidate biomarkers is influenced by the dietary intake of the infant.

METHODS

A cohort of 30 exclusively-breastfeeding mother-infant pairs from a small region of West Africa was used for this observational study. Plasma and milk from the mother and plasma from her infant were collected within 24 h, 3 months post partum. The lipid, sterol and glyceride composition was surveyed using direct infusion MS in positive and negative ion modes. Analysis employed a combination of univariate and multivariate tests.

RESULTS

The lipid profiles of mother and infant plasma samples are similar but distinguishable, and both are distinct from milk. Phosphatidylcholines (PC), cholesteryl esters (CEs) and cholesterol were more abundant in mothers with respect to their infants, e.g. PC(34:1) was 5.66% in mothers but 3.61% in infants (p = 3.60 × 10^-10), CE(18:2) was 8.05% in mothers but 5.18% in infants (p = 1.37 × 10^-11) whilst TGs were lower in mothers with respect to their infants, e.g. TG(52:2) was 2.74% in mothers and 4.23% in infants (p = 1.63 × 10^-05). A latent structure model showed that four lipids in infant plasma previously shown to be biomarkers clustered with cholesteryl esters in the maternal circulation.

CONCLUSION

This study found evidence that the abundance of individual lipid isoforms associated with infant development are associated with the abundance of individual molecular species in the mother's circulation.

Plasma phospholipid n-3 and n-6 polyunsaturated fatty acids in relation to cardiometabolic markers and gestational diabetes: A longitudinal study within the prospective NICHD Fetal Growth Studies

BACKGROUND

Despite dietary recommendations of polyunsaturated fatty acids (PUFAs) for cardiometabolic health, n-3 and n-6 PUFAs and their interplay in relation to diabetes risk remain debated. Importantly, data among pregnant women are scarce. We investigated individual plasma phospholipid n-3 and n-6 PUFAs in early to midpregnancy in relation to subsequent risk of gestational diabetes mellitus (GDM).

METHODS AND FINDINGS

Within the National Institute of Child Health and Human Development (NICHD) Fetal Growth Studies-Singleton Cohort (n = 2,802), individual plasma phospholipid n-3 and n-6 PUFAs levels were measured at gestational weeks (GWs) 10-14, 15-26, 23-31, and 33-39 among 107 GDM cases (ascertained on average at GW 27) and 214 non-GDM controls. Conditional logistic regression was used, adjusting for major risk factors for GDM. After adjusting for covariates, individual n-3 eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA), and docosahexaenoic acid (DHA) were inversely correlated with insulin-resistance markers, whereas individual n-6 dihomo-gamma-linolenic acid (DGLA) was positively correlated with insulin-resistance markers. At GW 15-26, a standard deviation (SD) increase in total n-3 PUFAs and individual n-3 DPA was associated with a 36% (adjusted odds ratio 0.64; 95% CI 0.42-0.96; P = 0.042) and 33% (0.67; 95% CI 0.45-0.99; P = 0.047) lower risk of GDM, respectively; however, the significance did not persist after post hoc false-discovery rate (FDR) correction (FDR-corrected P values > 0.05). Associations between total n-6 PUFAs and GDM were null, whereas associations with individual n-6 PUFAs were differential. Per SD increase, gamma-linolenic acid (GLA) at GWs 10-14 and DGLA at GWs 10-14 and 15-26 were significantly associated with a 1.40- to 1.95-fold higher risk of GDM, whereas docosatetraenoic acid (DTA) at GW 15-26 was associated with a 45% (0.55; 95% CI 0.37-0.83) lower risk of GDM (all FDR-corrected P values < 0.05). Null associations were observed for linoleic acid (LA) in either gestational window in relation to risk of GDM. Women with high (≥median) n-3 PUFAs and low (<median) n-6 PUFAs levels had a 64% (95% CI 0.14-0.95; P value = 0.039) lower risk of GDM versus women with low n-3 and high n-6 PUFAs. Limitations include the inability to distinguish between exogenous and endogenous influences on circulating PUFA levels and the lack of causality inherent in observational studies.

CONCLUSIONS

Our findings may suggest a potential role of primarily endogenously metabolized plasma phospholipid n-6 PUFAs including GLA, DGLA, and DTA in early to midpregnancy in the development of GDM. Null findings on primarily diet-derived n-3 EPA and DHA and n-6 LA do not provide strong evidence to suggest a beneficial role in prevention of GDM, although not excluding the potential benefit of EPA and DHA on glucose-insulin homeostasis given the inverse associations with insulin-resistance markers. Our findings highlight the importance of assessing individual circulating PUFAs to investigate their distinct pathophysiologic roles in glucose homeostasis in pregnancy.

Sex Dependent Dysregulation of Hepatic Glucose Production in Lean Type 2 Diabetic Rats

We have characterized a lean type 2 diabetic rat model by gestational low protein programming. We aimed to identify if the regulation of hepatic glucose production (HGP) via gluconeogenesis and glycogenolysis is affected and if there are any sex differences. Fasting (6-7 months old) type 2 diabetic rats received 2H2O followed by a primed constant rate infusion of [6,6-2H2] glucose. Blood samples were drawn during steady states after 4 h of fasting and following a euglycemic hyperinsulinemic clamp. HGP and the fraction of glucose derived from gluconeogenesis under fasting and euglycemic states were measured from steady state glucose enrichments after the infusion of [6,6-2H2]glucose and 2H2O tracers. Glycogenolysis was determined by calculating the difference between total HGP and gluconeogenesis rates. Hepatic gene expression of enzymes involved in HGP were quantified using qPCR. HGP rates was similar during fasting in both groups and sexes. However, under simulated fed condition, HGP rate was suppressed in controls but not in type 2 diabetic rats. They also showed inefficient HGP suppression in a simulated fed state. Differential analysis showed that suppression of both gluconeogenesis and glycogenolysis under simulated fed state was affected in these low protein programmed type 2 diabetic rats. These effects were greater in females when compared to males. Further, key genes involved in these processes like G6Pase, Pepck, pyruvate carboxylase, and glycogen phosphorylase in liver were dysregulated. Our data shows impaired suppression of HGP via gluconeogenesis and glycogenolysis in type 2 diabetic rats with greater effects on females.

Dlk1 expression relates to visceral fat expansion and insulin resistance in male and female rats with postnatal catch-up growth

BACKGROUND

Although prenatal and postnatal programming of metabolic diseases in adulthood is well established, the mechanisms underpinning metabolic programming are not. Dlk1, a key regulator of fetal development, inhibits adipocyte differentiation and restricts fetal growth.

METHODS

Assess DLk1 expression in a Wistar rat model of catch-up growth following intrauterine restriction. Dams fed ad libitum delivered control pups (C) and dams on a 50% calorie-restricted diet delivered pups with low birth weight (R). Restricted offspring fed a standard rat chow showed catch-up growth (R/C) but those kept on a calorie-restricted diet did not (R/R).

RESULTS

Decreased Dlk1 expression was observed in adipose tissue and skeletal muscle of R/C pups along with excessive visceral fat accumulation, decreased circulating adiponectin, increased triglycerides and HOMA-IR (from p < 0.05 to p < 0.0001). Moreover, in R/C pups the reduced Dlk1 expression in adipose tissue and skeletal muscle correlated with visceral fat (r = -0.820, p < 00001) and HOMA-IR (r = -0.745, p = 0.002).

CONCLUSIONS

Decreased Dlk1 expression relates to visceral fat expansion and insulin resistance in a rat model of catch-up growth following prenatal growth restriction. Modulation of Dlk1 expression could be among the targets for the early prevention of fetal programming of adult metabolic disorders.

The Association of Maternal Protein Intake during Pregnancy in Humans with Maternal and Offspring Insulin Sensitivity Measures

The purpose of this review is to critically evaluate the studies assessing the relations between protein intake during human pregnancy and insulin sensitivity measures in the mother and offspring, and to get a better understanding of the knowledge gaps that still exist. Overall, there is insufficient evidence to conclude about implications of higher amounts of protein intake during pregnancy on maternal or offspring insulin sensitivity. However, studies show a relation between protein quality and insulin sensitivity, such that animal protein may be associated with negative outcomes and plant protein may be associated with positive insulin sensitivity outcomes. There is an urgent need for standardized studies using comparable terminology to evaluate any potential relations between insulin sensitivity in mothers and offspring and truly low and high maternal protein intake while maintaining eucaloric balance to better inform about optimal protein dosage and quality during this period.

Cancer-Induced Reprogramming of Host Glucose Metabolism: "Vicious Cycle" Supporting Cancer Progression

Unrestricted cancer growth requires permanent supply of glucose that can be obtained from cancer-mediated reprogramming of glucose metabolism in the cancer-bearing host. The pathological mechanisms by which cancer cells exert their negative influence on host glucose metabolism are largely unknown. This paper proposes a mechanism of metabolic and hormonal changes that may favor glucose delivery to tumor (not host) cells by creating a cancer-host “vicious cycle” whose prolonged action drives cancer progression and promotes host cachexia. To verify this hypothesis, a feedback model of host-cancer interactions that create the “vicious cycle” via cancer-induced reprogramming of host glucose metabolism is proposed. This model is capable of answering some crucial questions as to how anabolic cancer cells can reprogram the systemic glucose metabolism and why these pathways were not observed in pregnancy. The current paper helps to better understanding a pathogenesis of cancer progression and identify hormonal/metabolic targets for anti-cancer treatment.

Maternal High-Protein Diet during Pregnancy Modifies Rat Offspring Body Weight and Insulin Signalling but Not Macronutrient Preference in Adulthood

Diet of mothers during gestation may impact offspring phenotype. This study evaluated the consequences of a maternal High-Protein (HP) diet during gestation on food preferences and phenotypic characteristics in adult rat offspring. Dams were fed a HP or a Normal-Protein (NP) isocaloric diet during gestation only. Weaned female pups were divided into 3 diet groups: NP control or one of two dietary self-selection (DSS) conditions. In DSS1, offspring had a free choice between proteins (100%) or a mix of carbohydrates (88%) and lipids (12%). In DSS2, the choice was between proteins (100%), carbohydrate (100%) or lipids (100%). DSS2 groups consumed more of their energy from protein and lipids, with a decreased carbohydrate intake (p < 0.0001) compared to NP groups, regardless of the maternal diet. Offspring from HP gestation dams fed the DSS2 diet (HPDSS2) had a 41.2% increase of total adiposity compared to NPDSS2 (p < 0.03). Liver Insulin receptor and Insulin substrate receptor 1 expression was decreased in offspring from HP compared to NP gestation dams. These results showed the specific effects of DSS and maternal diet and data suggested that adult, female offspring exposed to a maternal HP diet during foetal life were more prone to adiposity development, in response to postweaning food conditions.

Hypothalamic Dysfunction in Obesity and Metabolic Disorders

The hypothalamus is the brain region responsible for the maintenance of energetic homeostasis. The regulation of this process arises from the ability of the hypothalamus to orchestrate complex physiological responses such as food intake and energy expenditure, circadian rhythm, stress response, and fertility. Metabolic alterations such as obesity can compromise these hypothalamic regulatory functions. Alterations in circadian rhythm, stress response, and fertility further contribute to aggravate the metabolic dysfunction of obesity and contribute to the development of chronic disorders such as depression and infertility.At cellular level, obesity caused by overnutrition can damage the hypothalamus promoting inflammation and impairing hypothalamic neurogenesis. Furthermore, hypothalamic neurons suffer apoptosis and impairment in synaptic plasticity that can compromise the proper functioning of the hypothalamus. Several factors contribute to these phenomena such as ER stress, oxidative stress, and impairments in autophagy. All these observations occur at the same time and it is still difficult to discern whether inflammatory processes are the main drivers of these cellular dysfunctions or if the hypothalamic hormone resistance (insulin, leptin, and ghrelin) can be pinpointed as the source of several of these events.Understanding the mechanisms that underlie the pathophysiology of obesity in the hypothalamus is crucial for the development of strategies that can prevent or attenuate the deleterious effects of obesity.

Ovarian and Extra-Ovarian Mediators in the Development of Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is a heterogeneous endocrine disorder affecting women of reproductive age. The origin of PCOS is still not clear and appears to be a function of gene x environment interactions. This review addresses the current knowledge of the genetic and developmental contributions to the etiology of PCOS, the ovarian and extra-ovarian mediators of PCOS and the gaps and key challenges that need to be addressed in the diagnosis, treatment and prevention of PCOS.

DNA methylation of the promoter region of bnip3 and bnip3l genes induced by metabolic programming

BACKGROUND

Environmental changes of biotic or abiotic nature during critical periods of early development may exert a profound influence on physiological functions later in life. This process, named developmental programming can also be driven through parental nutrition. At molecular level, epigenetic modifications are the most likely candidate for persistent modulation of genes expression in later life.

RESULTS

In order to investigate epigenetic modifications induced by programming in rainbow trout, we focused on bnip3 and bnip3l paralogous genes known to be sensitive to environmental changes but also regulated by epigenetic modifications. Two specific stimuli were used: (i) early acute hypoxia applied at embryo stage and (ii) broodstock and fry methionine deficient diet, considering methionine as one of the main methyl-group donor needed for DNA methylation. We observed a programming effect of hypoxia with an increase of bnip3a and the four paralogs of bnip3l expression level in fry. In addition, parental methionine nutrition was correlated to bnip3a and bnip3lb1 expression showing evidence for early fry programming. We highlighted that both stimuli modified DNA methylation levels at some specific loci of bnip3a and bnip3lb1.

CONCLUSION

Overall, these data demonstrate that methionine level and hypoxia stimulus can be of critical importance in metabolic programming. Both stimuli affected DNA methylation of specific loci, among them, an interesting CpG site have been identified, namely - 884 bp site of bnip3a, and may be positively related with mRNA levels.

Treatment of type 2 diabetes mellitus via reversing insulin resistance and regulating lipid homeostasis in vitro and in vivo using cajanonic acid A

The present study investigated the effects of cajanonic acid A (CAA), extracted from the leaves of Cajanus cajan (L.) Millsp with a purity of 98.22%, on the regulatory mechanisms of glucose and lipid metabolism. HepG2 cells transfected with a protein-tyrosine phosphatase 1B (PTP1B) overexpression plasmid were established. The cells, induced with insulin resistance by dexamethasone (Dex) treatment, together with type 2 diabetes mellitus (T2DM) model rats and ob/ob mice, were used in the present study. The effects of CAA treatment on the differentiation of 3T3-L1 adipocytes were determined using Oil Red O. The expression levels of insulin signaling factors were detected via reverse transcription-quantitative polymerase chain reaction and western blot analyses. The results revealed that the overexpression of PTP1B contributed to insulin resistance, which was reversed by CAA treatment via inhibiting the activity of PTP1B and by regulating the expression of associated insulin signaling factors. The treatment of cell lines with Dex led to increased expression of PTP1B but decreased glucose consumption, and decreased tyrosine phosphorylation of insulin receptor, insulin receptor substrate 1, and phosphoinositide 3-kinase. Treatment with CAA not only reduced the fasting blood glucose levels and protected organs from damage, but also reduced the serum fasting levels of total cholesterol, triglycerides and low-density lipoprotein cholesterol in the T2DM rats. CAA treatment also inhibited adipocyte differentiation and decreased the mRNA levels of various adipogenic genes. Furthermore, CAA treatment restored the transduction of insulin signaling by regulating the expression of PTP1B and associated insulin signaling factors. Treatment with CAA also reduced the problems associated with hyperglycemia and hyperlipidemia. In conclusion, CAA may be used to cure T2DM via restoring insulin resistance and preventing obesity.

Aberrant DNA Methylation Involved in Obese Women with Systemic Insulin Resistance

Background

Epigenetics has been recognized as a significant regulator in many diseases. White adipose tissue (WAT) epigenetic dysregulation is associated with systemic insulin resistance (IR). The aim of this study was to survey the differential methylation of genes in obese women with systemic insulin resistance by DNA methylation microarray.

Methods

The genome-wide methylation profile of systemic insulin resistant obese women was obtained from Gene Expression Omnibus database. After data preprocessing, differing methylation patterns between insulin resistant and sensitive obese women were identified by Student's t-test and methylation value differences. Network analysis was then performed to reveal co-regulated genes of differentially methylated genes. Functional analysis was also implemented to reveal the underlying biological processes related to systemic insulin resistance in obese women.

Results

Relative to insulin sensitive obese women, we initially screened 10,874 differentially methylated CpGs, including 7402 hyper-methylated sites and 6073 hypo-methylated CpGs. Our analysis identified 4 significantly differentially methylated genes, including SMYD3, UST, BCL11A, and BAI3. Network and functional analyses found that these differentially methylated genes were mainly involved in chondroitin and dermatan sulfate biosynthetic processes.

Conclusion

Based on our study, we propose several epigenetic biomarkers that may be related to obesity-associated insulin resistance. Our results provide new insights into the epigenetic regulation of disease etiology and also identify novel targets for insulin resistance treatment in obese women.

A cross-sectional survey investigating women's information sources, behaviour, expectations, knowledge and level of satisfaction on advice received about diet and supplements before and during pregnancy

BACKGROUND

The reported long-term effects of poor maternal nutrition and uptake of recommended supplements before and during pregnancy was the impetus behind this study. Our objectives were to investigate and understand women's expectations, knowledge, behaviour and information sources used regarding the use of nutrition and vitamin supplements before and during pregnancy.

METHODS

A cross-sectional survey using a self-administered questionnaire was undertaken. A purposive sampling technique was used. Women attending the antenatal clinic at Croydon University Hospital during 2015 were invited to take part in the study. The data was analysed using descriptive statistics, paired sample T-tests and Chi-squared tests, with the level of significance set at 5% (p < 0.05).

RESULTS

A total of 133 pregnant women completed the survey. Analysis of the results showed that women are currently using electronic resources (33%, n = 42) rather than healthcare professionals (19%, n = 25) as an information source before pregnancy. Women who sourced information through the internet were significantly more likely to take folic acid (p = 0.006) and vitamin D (p = 0.004) before pregnancy. Women preferred to receive information from the antenatal clinic (62%, n = 83), internet (46%, n = 61) and from mobile applications (27%, n = 36). Although women believed they had sufficient knowledge (60%, n = 80) and had received adequate advice (53%, n = 70) concerning the correct supplements to take, this was not demonstrated in their behaviour, with only a small number of women (37%, n = 49) taking a folic acid supplement before pregnancy. Women mistakenly perceived the timing of supplement advice as correct, with only a small number of women (18%, n = 23) considering the advice on supplements as too late.

CONCLUSIONS

Despite the small sample size, this study demonstrated that women did not receive timely and/or accurate advice to enable them to take the recommended supplements at the optimal time. Women had the misconception that they understood the correct use of pregnancy supplements. This misunderstanding may be prevented by providing women intending to become pregnant with a structured, approved electronic source of information that improves their supplements uptake.

Folate treatment partially reverses gestational low-protein diet-induced glucose intolerance and the magnitude of reversal is age and sex dependent

OBJECTIVES

Gestational low-protein (LP) programming causes glucose intolerance (GI) and insulin resistance (IR) in adult offspring. Folate supplementation has been shown to rescue the offspring from various programming effects. The aim of this study was to investigate whether folate supplementation during pregnancy reverses LP-induced GI and IR.

METHODS

Pregnant rats were fed control (20% protein), isocaloric low-protein (LP, 6%) or LP with 5 mg/kg folate (LPF) diets from gestational day 4 to delivery. The control diet was given during lactation and to pups after weaning. Glucose tolerance test was done at 1, 2, and 3 mo of age followed by euglycemic-hyperinsulinemic clamp at 4 mo. Rats were sacrificed at 4 mo and their gonadal, renal, inguinal, brown fat, and pancreas were weighed and expressed relative to their body weight.

RESULTS

LP- and LPF-fed dams showed similar weight loss during late pregnancy after decreased feed intake. Both LP and LPF pups were smaller at birth but their weights caught up like that of controls by 3 mo. In males, folate supplementation reduced LP-induced GI at 2 mo (glucose area under the curve [AUC]: 1940 mmol/L × 180 min in LP, 1629 mmol/L × 180 min in LPF, and 1653 mmol/L × 180 min in controls; P <0.05, LP versus control and P <0.01, LP versus LPF) but the effect diminished at 3 mo. In females, folate reduced GI at 1 mo (glucose AUC: 1406 mmol/L × 180 min in LP, 1264 mmol/L × 180 min in LPF, and 1281 mmol/L × 180 min in controls; P <0.05, LP versus control and LP versus LPF) but had no effect at 2 and 3 mo. Interestingly, the LPF group had higher pancreatic weights than other groups, suggesting that folate helps in pancreatic development enabling the LPF rats to produce/secrete more insulin to maintain euglycemia. Euglycemic-hyperinsulinemic clamp shows both LP and LPF are insulin resistant compared with controls by 4 mo with LPF more severe than LP in males. Interestingly, females were more insulin resistant than males.

CONCLUSIONS

Folate treatment partially reverses LP-induced GI and the magnitude of reversal is age and sex dependent. Furthermore, folate treatment does not reverse IR in either sex but makes it worse in males at 4 mo. The present study demonstrated that folate treatment is not sufficient to rescue the LP programming effects.

Early nutrition and ageing: can we intervene?

Ageing, a complex process that results in progressive decline in intrinsic physiological function leading to an increase in mortality rate, has been shown to be affected by early life nutrition. Accumulating data from animal and epidemiological studies indicate that exposure to a suboptimal nutritional environment during fetal life can have long-term effects on adult health. In this paper, we discuss the impact of early life nutrition on the development of age-associated diseases and life span. Special emphasis is given to studies that have investigated the molecular mechanisms underlying these effects. These include permanent structural and cellular changes including epigenetics modifications, oxidative stress, DNA damage and telomere shortening. Potential strategies targeting these mechanisms, in order to prevent or alleviate the detrimental effects of suboptimal early nutrition on lifespan and age-related diseases, are also discussed. Although recent reports have already identified effective therapeutic interventions, such as antioxidant supplementation, further understanding of the extent and nature of how early nutrition influences the ageing process will enable the development of novel and more effective approaches to improve health and extend human lifespan in the future.

GWAS on prolonged gestation (post-term birth): analysis of successive Finnish birth cohorts

Background

Gestation is a crucial timepoint in human development. Deviation from a term gestational age correlates with both acute and long-term adverse health effects for the child. Both being born preterm and post-term, that is, having short and long gestational ages, are heritable and influenced by the prenatal and perinatal environment. Despite the obvious heritable component, specific genetic influences underlying differences in gestational age are poorly understood.

Methods

We investigated the genetic architecture of gestational age in 9141 individuals, including 1167 born post-term, across two Northern Finland cohorts born in 1966 or 1986.

Results

Here we identify one globally significant intronic genetic variant within the ADAMTS13 gene that is associated with prolonged gestation (p=4.85×10−8). Additional variants that reached suggestive levels of significance were identified within introns at the ARGHAP42 and TKT genes, and in the upstream (5’) intergenic regions of the B3GALT5 and SSBP2 genes. The variants near the ADAMTS13, B3GALT5, SSBP2 and TKT loci are linked to alterations in gene expression levels (cis-eQTLs). Luciferase assays confirmed the allele specific enhancer activity for the BGALT5 and TKT loci.

Conclusions

Our findings provide the first evidence of a specific genetic influence associated with prolonged gestation. This study forms a foundation for a better understanding of the genetic and long-term health risks faced by induced and post-term individuals. The long-term risks for induced individuals who have a previously overlooked post-term potential may be a major issue for current health providers.

Transient postnatal overfeeding causes liver stress-induced premature senescence in adult mice

Unbalanced nutrition early in life is increasingly recognized as an important factor in the development of chronic, non-communicable diseases at adulthood, including metabolic diseases. We aimed to determine whether transient postnatal overfeeding (OF) leads to liver stress-induced premature senescence (SIPS) of hepatocytes in association with liver structure and hepatic function alterations. Litters sizes of male C57BL/6 mice were adjusted to 9 pups (normal feeding, NF) or reduced to 3 pups during the lactation period to induce transient postnatal OF. Compared to the NF group, seven-month-old adult mice transiently overfed during the postnatal period were overweight and developed glucose intolerance and insulin resistance. Their livers showed microsteatosis and fibrosis, while hepatic insulin signaling and glucose transporter protein expressions were altered. Increased hepatic oxidative stress (OS) was observed, with increased superoxide anion production, glucose-6-phosphate dehydrogenase protein expression, oxidative DNA damage and decreased levels of antioxidant defense markers, such as superoxide dismutase and catalase proteins. Hepatocyte senescence was characterized by increased p21^WAF, p53, Acp53, p16^INK4a and decreased pRb/Rb and Sirtuin-1 (SIRT-1) protein expression levels. Transient postnatal OF induces liver OS at adulthood, associated with hepatocyte SIPS and alterations in liver structure and hepatic functions, which could be mediated by a SIRT-1 deficiency.

The cellular and molecular bases of leptin and ghrelin resistance in obesity

Obesity, a major risk factor for the development of diabetes mellitus, cardiovascular diseases and certain types of cancer, arises from a chronic positive energy balance that is often due to unlimited access to food and an increasingly sedentary lifestyle on the background of a genetic and epigenetic vulnerability. Our understanding of the humoral and neuronal systems that mediate the control of energy homeostasis has improved dramatically in the past few decades. However, our ability to develop effective strategies to slow the current epidemic of obesity has been hampered, largely owing to the limited knowledge of the mechanisms underlying resistance to the action of metabolic hormones such as leptin and ghrelin. The development of resistance to leptin and ghrelin, hormones that are crucial for the neuroendocrine control of energy homeostasis, is a hallmark of obesity. Intensive research over the past several years has yielded tremendous progress in our understanding of the cellular pathways that disrupt the action of leptin and ghrelin. In this Review, we discuss the molecular mechanisms underpinning resistance to leptin and ghrelin and how they can be exploited as targets for pharmacological management of obesity.

Protein malnutrition blunts the increment of taurine transporter expression by a high-fat diet and impairs taurine reestablishment of insulin secretion

Taurine (Tau) restores β-cell function in obesity; however, its action is lost in malnourished obese rodents. Here, we investigated the mechanisms involved in the lack of effects of Tau in this model. C57BL/6 mice were fed a control diet (CD) (14% protein) or a protein-restricted diet (RD) (6% protein) for 6 wk. Afterward, mice received a high-fat diet (HFD) for 8 wk [CD + HFD (CH) and RD + HFD (RH)] with or without 5% Tau supplementation after weaning on their drinking water [CH + Tau (CHT) and RH + Tau (RHT)]. The HFD increased insulin secretion through mitochondrial metabolism in CH and RH. Tau prevented all those alterations in CHT only. The expression of the taurine transporter (Tau-T), as well as Tau content in pancreatic islets, was increased in CH but had no effect on RH. Protein malnutrition programs β cells and impairs Tau-induced restoration of mitochondrial metabolism and biogenesis. This may be associated with modulation of the expression of Tau-T in pancreatic islets, which may be responsible for the absence of effect of Tau in protein-malnourished obese mice.-Branco, R. C. S., Camargo, R. L., Batista, T. M., Vettorazzi, J. F., Borck, P. C., dos Santos-Silva, J. C. R., Boschero, A. C., Zoppi, C. C., Carneiro, E. M. Protein malnutrition blunts the increment of taurine transporter expression by a high-fat diet and impairs taurine reestablishment of insulin secretion.