Increased maternal fat consumption during pregnancy alters body composition in neonatal mice

Post mortem analysis of hepatic volume and lipid content by magnetic resonance imaging and spectroscopy in fixed murine neonates

Maternal obesity and hyperglycemia are linked to an elevated risk for obesity, diabetes, and steatotic liver disease in the adult offspring. To establish and validate a noninvasive workflow for perinatal metabolic phenotyping, fixed neonates of common mouse strains were analyzed postmortem via magnetic resonance imaging (MRI)/magnetic resonance spectroscopy (MRS) to assess liver volume and hepatic lipid (HL) content. The key advantage of nondestructive MRI/MRS analysis is the possibility of further tissue analyses, such as immunohistochemistry, RNA extraction, and even proteomics, maximizing the data that can be gained per individual and therefore facilitating comprehensive correlation analyses. This study employed an MRI and 1H-MRS workflow to measure liver volume and HL content in 65 paraformaldehyde-fixed murine neonates at 11.7 T. Liver volume was obtained using semiautomatic segmentation of MRI acquired by a RARE sequence with 0.5-mm slice thickness. HL content was measured by a STEAM sequence, applied with and without water suppression. T1 and T2 relaxation times of lipids and water were measured for respective correction of signal intensity. The HL content, given as CH2/(CH2 + H2O), was calculated, and the intrasession repeatability of the method was tested. The established workflow yielded robust results with a variation of ~3% in repeated measurements for HL content determination. HL content measurements were further validated by correlation analysis with biochemically assessed triglyceride contents (R2 = 0.795) that were measured in littermates. In addition, image quality also allowed quantification of subcutaneous adipose tissue and stomach diameter. The highest HL content was measured in C57Bl/6N (4.2%) and the largest liver volume and stomach diameter in CBA (53.1 mm3 and 6.73 mm) and NMRI (51.4 mm3 and 5.96 mm) neonates, which also had the most subcutaneous adipose tissue. The observed effects were independent of sex and litter size. In conclusion, we have successfully tested and validated a robust MRI/MRS workflow that allows assessment of morphology and HL content and further enables paraformaldehyde-fixed tissue-compatible subsequent analyses in murine neonates.

Expression of glucagon-like peptide-1 and glucose-dependent insulinotropic polypeptide in the rat submandibular gland is influenced by pre- and post-natal high-fat diet exposure

Background: Incretins, i.e., glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) promote insulin secretion to reduce postprandial blood sugar. Previous studies found incretins in the salivary glands. However, the role of GLP-1 and GIP in the submandibular gland (SMG) is unclear. This study investigates the effects of a high-fat diet (HFD) on the expression of GLP-1 and GIP throughout the development of rat SMG. Methods: Pregnant 11-week-old Wistar rats were divided into two groups: those fed on a standard diet (n = 5) and those fed on a HFD (n = 5). From day 7 of pregnancy and throughout the lactation period, all the rats were fed on either a chow diet or HFD. The newborns were divided into four subgroups (n = 6): standard diet males (SM), HFD males (HM), standard diet females (SF), and HFD females (HF). The SMGs of 3- and 10-week-old rats from each subgroup were collected under general anesthesia. Moreover, body weight, food intake, and fasting blood sugar were measured. The mRNA expression of GLP-1 and GIP was quantified, and the localization was observed using immunohistochemistry (p < 0.05). Results: GLP-1 mRNA expression was statistically significantly more upregulated in HM than in HF at 3 weeks. Moreover, GLP-1 mRNA expression was significantly higher in HM than in both SM and HF at 10 weeks. Although a decreasing trend was observed in GIP mRNA expression in both 3- and 10-week-old rats fed on a HFD, a significant difference between HM and SM only occurred at 3 weeks. Furthermore, the GIP mRNA expression of HM was lower than that of HF at 10 weeks. Immunohistochemical staining revealed GLP-1 and GIP expression mainly in the SMG duct system. Moreover, vacuolated cytoplasm in the duct was observed in rats fed on a HFD. Conclusion: Exposure to HFD during pre- and post-natal periods increased GLP-1 mRNA expression in the SMGs of male rats. However, GIP expression decreased following the HFD in male newborns. Furthermore, a decreasing trend of GIP mRNA expression was observed in male newborns after HFD feeding. Sex influenced incretin hormones secretion and obesity-related conditions. HFD during pre- and post-natal periods reprograms the epigenome, contributing to subsequent disease development.

The Legacy of Parental Obesity: Mechanisms of Non-Genetic Transmission and Reversibility

While a dramatic increase in obesity and related comorbidities is being witnessed, the underlying mechanisms of their spread remain unresolved. Epigenetic and other non-genetic mechanisms tend to be prominent candidates involved in the establishment and transmission of obesity and associated metabolic disorders to offspring. Here, we review recent findings addressing those candidates, in the context of maternal and paternal influences, and discuss the effectiveness of preventive measures.

A maternal higher-complex carbohydrate diet increases bifidobacteria and alters early life acquisition of the infant microbiome in women with gestational diabetes mellitus

Gestational diabetes mellitus (GDM) is associated with considerable imbalances in intestinal microbiota that may underlie pathological conditions in both mothers and infants. To more definitively identify these alterations, we evaluated the maternal and infant gut microbiota through the shotgun metagenomic analysis of a subset of stool specimens collected from a randomized, controlled trial in diet-controlled women with GDM. The women were fed either a CHOICE diet (60% complex carbohydrate/25% fat/15% protein, n=18) or a conventional diet (CONV, 40% complex carbohydrate/45% fat/15% protein, n=16) from 30 weeks' gestation through delivery. In contrast to other published studies, we designed the study to minimize the influence of other dietary sources by providing all meals, which were eucaloric and similar in fiber content. At 30 and 37 weeks' gestation, we collected maternal stool samples; performed the fasting measurements of glucose, glycerol, insulin, free fatty acids, and triglycerides; and administered an oral glucose tolerance test (OGTT) to measure glucose clearance and insulin response. Infant stool samples were collected at 2 weeks, 2 months, and 4-5 months of age. Maternal glucose was controlled to conventional targets in both diets, with no differences in Homeostatic Model Assessment of Insulin Resistance (HOMA-IR). No differences in maternal alpha or beta diversity between the two diets from baseline to 37 weeks' gestation were observed. However, women on CHOICE diet had higher levels of Bifidobacteriaceae, specifically Bifidobacterium adolescentis, compared with women on CONV. Species-level taxa varied significantly with fasting glycerol, fasting glucose, and glucose AUC after the OGTT challenge. Maternal diet significantly impacted the patterns of infant colonization over the first 4 months of life, with CHOICE infants showing increased microbiome alpha diversity (richness), greater Clostridiaceae, and decreased Enterococcaceae over time. Overall, these results suggest that an isocaloric GDM diet containing greater complex carbohydrates with reduced fat leads to an ostensibly beneficial effect on the maternal microbiome, improved infant gut microbiome diversity, and reduced opportunistic pathogens capable of playing a role in obesity and immune system development. These results highlight the critical role a maternal diet has in shaping the maternal and infant microbiome in women with GDM.

A comprehensive review on high fat diet-induced diabetes mellitus: An epigenetic view

Modern lifestyle, genetics, nutritional overload through high-fat diet attributed prevalence and diabetes outcomes with various complications primarily due to obesity in which energy-dense diets frequently affect metabolic health. One possible issue usually associated with elevated chronic fat intake is insulin resistance, and hyperglycaemia constitutes an important function in altering the carbohydrates and lipids metabolism. Similarly, in assessing human susceptibility to weight gain and obesity, genetic variations play a central role, contributing to keen interest in identifying the possible role of epigenetics as a mediator of gene-environmental interactions influencing the production of type 2 diabetes mellitus and its related concerns. Epigenetic modifications associated with the acceptance of a sedentary lifestyle and environmental stress factors in response to energy intake and expenditure imbalances complement genetic alterations and lead to the production and advancement of metabolic disorders such as diabetes and obesity. Methylation of DNA, histone modifications and increases in the expression of non-coding RNAs can result in reduced transcriptional activity of key β-cell genes thus creating insulin resistance. Epigenetics contribute to changes in the expression of the underlying insulin resistance and insufficiency gene networks, along with low-grade obesity-related inflammation, increased ROS generation and DNA damage in multi organs. This review focused on epigenetic mechanisms and metabolic regulations associated with high fat diet (HFD)-induced diabetes mellitus.

Obesity, not a high fat, high sucrose diet alone, induced glucose intolerance and cardiac dysfunction during pregnancy and postpartum

Cardiovascular disease is the leading cause of death in women during pregnancy and the postpartum period. Obesity is an independent risk factor for cardiovascular diseases. Nearly 60% of women of reproductive age are considered overweight or obese, cardiovascular disease morbidity and mortality continue to be pervasive. The objective of this study was to determine the effects of an obesogenic diet on the cardiometabolic health of dams during pregnancy and postpartum. Female mice were fed either a high-fat, high-sucrose diet (HFHS) or a refined control diet (CON) for 8 weeks before initiation of pregnancy and throughout the study period. Mice in the HFHS showed two distinct phenotypes, obesity-prone (HFHS/OP) and obesity resistance (HFHS/OR). Pre-pregnancy obesity (HFHS/OP) induced glucose intolerance before pregnancy and during postpartum. Systolic function indicated by the percent fractional shortening (%FS) was significantly decreased in the HFHS/OP at late pregnancy (vs. HFHS/OR) and weaning (vs. CON), but no differences were found at 6 weeks of postpartum among groups. No induction of pathological cardiac hypertrophy markers was found during postpartum. Plasma adiponectin was decreased while total cholesterol was increased in the HFHS/OP. Our results suggested that obesity, not the diet alone, negatively affected cardiac adaptation during pregnancy and postpartum.

Maternal dietary fat intake during pregnancy and newborn body composition

OBJECTIVE

Increased infant birth weight and adiposity are associated with an altered risk of adult chronic diseases. The objective was to investigate the association between maternal dietary fat intake during pregnancy and newborn adiposity.

STUDY DESIGN

The study included 79 singleton pregnancies. Associations between maternal dietary fat intake during each trimester and infant adiposity at birth were assessed.

RESULT

Average total grams of maternal total dietary fat and unsaturated fat intake during pregnancy correlated with infant percent body fat after adjusting for potential confounding variables (r = 0.23, p = 0.045; r = 0.24, p = 0.037). Maternal average daily intake of total fat, saturated fat, and unsaturated fat during the second trimester of pregnancy were each associated with infant percent body fat (r = 0.25, p = 0.029; r = 0.23, p = 0.046; r = 0.25, p = 0.031; respectively).

CONCLUSIONS

The second trimester of pregnancy is a key time period for fetal adipose tissue metabolic programming and therefore a target for nutritional intervention.

Maternal fats and pregnancy complications: Implications for long-term health

Pregnancy imposes increased nutritional requirements for the well being of the mother and fetus. Maternal lipid metabolism is critical for fetal development and long-term health of the offspring as it plays a key role in energy storage, tissue growth and cell signaling. Maternal fat composition is considered as a modifiable risk for abnormal lipid metabolism and glucose tolerance during pregnancy. Data derived from observational studies demonstrate that higher intake of saturated fats during pregnancy is associated with pregnancy complications (preeclampsia, gestational diabetes mellitus and preterm delivery) and poor birth outcomes (intra uterine growth retardation and large for gestational age babies). On the other hand, prenatal long chain polyunsaturated fatty acids status is shown to improve birth outome. In this article, we discuss the role of maternal lipids during pregnancy on fetal growth and development and its consequences on the health of the offspring.

Maternal Obesity During Pregnancy and Lactation Influences Offspring Obesogenic Adipogenesis but Not Developmental Adipogenesis in Mice

Obesity is an escalating health crisis of pandemic proportions and by all accounts it has yet to reach its peak. Growing evidence suggests that obesity may have its origins in utero. Recent studies have shown that maternal obesity during pregnancy may promote adipogenesis in offspring. However, these studies were largely based on cell culture models. Whether or not maternal obesity impacts on offspring adipogenesis in vivo remains to be fully established. Furthermore, in vivo adipogenic differentiation has been shown to happen at distinct time periods, one during development (developmental adipogenesis-which is complete by 4 weeks of age in mice) and another in adulthood in response to feeding a high-fat (HF) diet (obesogenic adipogenesis). We therefore set out to determine whether maternal obesity impacted on offspring adipocyte hyperplasia in vivo and whether maternal obesity impacted on developmental or obesogenic adipogenesis, or both. Our findings reveal that maternal obesity is associated with enhanced obesogenic adipogenesis in HF-fed offspring. Interestingly, in newly weaned (4-week-old) offspring, maternal obesity is associated with adipocyte hypertrophy, but there were no changes in adipocyte number. Our results suggest that maternal obesity impacts on offspring obesogenic adipogenesis but does not affect developmental adipogenesis.

Maternal high fat diet compromises survival and modulates lung development of offspring, and impairs lung function of dams (female mice)

Background

Epidemiological studies have identified strong relationships between maternal obesity and offspring respiratory dysfunction; however, the causal direction is not known. We tested whether maternal obesity alters respiratory function of offspring in early life.

Methods

Female C57Bl/6 J mice were fed a high or low fat diet prior to and during two rounds of mating and resulting pregnancies with offspring lung function assessed at 2 weeks of age. The lung function of dams was measured at 33 weeks of age.

Results

A high fat diet caused significant weight gain prior to conception with dams exhibiting elevated fasting glucose, and glucose intolerance. The number of surviving litters was significantly less for dams fed a high fat diet, and surviving offspring weighed more, were longer and had larger lung volumes than those born to dams fed a low fat diet. The larger lung volumes significantly correlated in a linear fashion with body length. Pups born from the second pregnancy had reduced tissue elastance compared to pups born from the first pregnancy, regardless of the dam’s diet. As there was reduced offspring survival born to dams fed a high fat diet, the statistical power of lung function measures of offspring was limited. There were signs of increased inflammation in the bronchoalveolar lavage fluid of dams (but not offspring) fed a high fat diet, with more tumour necrosis factor-α, interleukin(IL)-5, IL-33 and leptin detected. Dams that were fed a high fat diet and became pregnant twice had reduced fasting glucose immediately prior to the second mating, and lower levels of IL-33 and leptin in bronchoalveolar lavage fluid.

Conclusions

While maternal high fat diet compromised litter survival, it also promoted somatic and lung growth (increased lung volume) in the offspring. Further studies are required to examine downstream effects of this enhanced lung volume on respiratory function in disease settings.

Semi-synthetic diet versus diet using natural ingredients-Comparative study in female Golden Syrian hamsters

Semi-synthetic diets (SSD) are recommended and are widely used to carry out experiments in rodents. However, in our experiments planned to carry out generation studies in female Golden Syrian hamsters using semi-synthetic diets, it was observed that the hamsters did not conceive as a result of decreased food intake. In this paper, we present the effects of both semi-synthetic diets and natural source diets (NSD) on food intake, body weight and reproductive performance of this species. Four-week-old female hamsters were equally divided into 3 groups and initially acclimatized for 2 weeks on natural chow diet (NCD). Thereafter, they were fed either control diet, high fat diet (HFD) or low protein diet (LPD) based on semi-synthetic/natural source ingredients until 12 weeks. Daily food intake and weekly body weights were monitored. Hamsters were kept for mating for about 2 weeks from 10th week onwards, during which the pregnancy confirmation test was done using standard vaginal smear examination. In all the groups fed SSD, the food intake was very poor, hamsters lost body weight and did not conceive, thus preventing us from carrying out further experiments. Hamsters fed NCD/NSD ingested more than twice as much as hamsters fed SSD (7-8 g/day/hamster against 3 g/day/hamster on average respectively). Based on the results of the current research, we conclude that the routinely used semi-synthetic diet is not suitable for carrying out studies in female hamsters. We suggest that scientists must also consider the unusual biological characteristics of a given species besides other biological factors. It is therefore critical to select appropriate biological models and diets that provide optimal sensitivity and specificity to accomplish the research objectives.

Maternal dietary ratio of linoleic acid to alpha-linolenic acid during pregnancy has sex-specific effects on placental and fetal weights in the rat

Background

Increased consumption of linoleic acid (LA, omega-6) in Western diets coupled with the pro-inflammatory and adipogenic properties of its derivatives has led to suggestions that fetal exposure to this dietary pattern could be contributing to the intergenerational cycle of obesity.

Method

This study aimed to evaluate the effects of maternal consumption of a LA to alpha-linolenic acid (ALA) ratio similar to modern Western diets (9:1) compared to a lower ratio (1:1.5) on placental and fetal growth, and to determine any cumulative effects by feeding both diets at two total fat levels (18% vs 36% fat w/w). Female Wistar rats (n = 5–7/group) were assigned to one of the four experimental diets prior to mating until 20d of gestation.

Results

Fatty acid profiles of maternal and fetal blood and placental tissue at 20d gestation were different between dietary groups, and largely reflected dietary fatty acid composition. Female fetuses were heavier (2.98 ± 0.06 g vs 3.36 ± 0.07 g, P < 0.01) and male placental weight was increased (0.51 ± 0.02 g vs 0.58 ± 0.02 g, P < 0.05) in the low LA:ALA groups. Female fetuses of dams exposed to a 36% fat diet had a reduced relative liver weight irrespective of LA:ALA ratio (7.61 ± 0.22% vs 6.93 ± 0.19%, P < 0.05). These effects occurred in the absence of any effect of the dietary treatments on maternal bodyweight, fat deposition or expression of key lipogenic genes in maternal and fetal liver or maternal adipose tissue.

Conclusion

These findings suggest that both the total fat content as well as the LA:ALA ratio of the maternal diet have sex-specific implications for the growth of the developing fetus.

The Effect of Maternal Obesity on Placental Cell-Free DNA Release in a Mouse Model

BACKGROUND

The fetal fraction of cell-free DNA (cfDNA) in maternal plasma is decreased in obese women. The underlying mechanism is not well understood. The amount of cfDNA released from the placenta has not been directly examined in maternal obesity.

OBJECTIVE

We sought to quantify release of cfDNA from the placenta and fetal membranes in maternal diet-induced obesity using explant cultures in an established mouse model.

STUDY DESIGN

C57BL6/J females were fed either 60% high-fat diet or 10% fat-matched control diet for 14 weeks prepregnancy and throughout gestation. Placentas and fetal membranes were collected on e18 and randomly allocated to time 0-, 1-, or 6-hour culture times. The CfDNA was isolated from culture media, quantified, and normalized to tissue weight.

RESULTS

Placentas from obese dams released significantly less cfDNA compared to those of lean dams at time 0 (45.8 ± 4.3 ng/mg vs 65.6 ± 7.9 ng/mg, P = .02). Absolute cfDNA levels increased with longer placental culture, with no significant differences between obese and lean dams at 1 and 6 hours. Membranes released significantly less cfDNA than did placentas at every time point.

CONCLUSIONS

Maternal obesity is associated with decreased release of cfDNA from the placenta compared to lean controls immediately after tissue harvest. This may provide an alternative explanation for the lower fetal fraction of cfDNA noted in maternal obesity.

Opposing Actions of Developmental Trichloroethylene and High-Fat Diet Coexposure on Markers of Lipogenesis and Inflammation in Autoimmune-Prone Mice

Trichloroethylene (TCE) is a widespread environmental pollutant associated with immunotoxicity and autoimmune disease. Previous studies showed that mice exposed from gestation through early life demonstrated CD4+ T cell alterations and autoimmune hepatitis. Determining the role of one environmental risk factor for any disease is complicated by the presence of other stressors. Based on its known effects, we hypothesized that developmental overnutrition in the form of a moderately high-fat diet (HFD) consisting of 40% kcal fat would exacerbate the immunotoxicity and autoimmune-promoting effects of low-level (<10 μg/kg/day) TCE in autoimmune-prone MRL+/+ mice over either stressor alone. When female offspring were evaluated at 27 weeks of age we found that a continuous exposure beginning at 4 weeks preconception in the dams until 10 weeks of age in offspring that TCE and HFD promoted unique effects that were often antagonistic. For a number of adiposity endpoints, TCE significantly reversed the expected effects of HFD on expression of genes involved in fatty acid synthesis/insulin resistance, as well as mean pathology scores of steatosis. Although none of the animals developed pathological signs of autoimmune hepatitis, the mice generated unique patterns of antiliver antibodies detected by western blotting attributable to TCE exposure. A majority of cytokines in liver, gut, and splenic CD4+ T cells were significantly altered by TCE, but not HFD. Levels of bacterial populations in the intestinal ileum were also altered by TCE exposure rather than HFD. Thus, in contrast to our expectations this coexposure did not promote synergistic effects.

Infant Adiposity is Independently Associated with a Maternal High Fat Diet but not Related to Niacin Intake: The Healthy Start Study

Objectives Over-nutrition during pregnancy resulting from maternal obesity or an unhealthy diet can lead to excess infant adiposity at birth. Specific dietary macro- and micronutrients have been shown to increase fat cell development in both in-vitro and in-vivo models and may therefore link maternal diet to increased infant adiposity. We hypothesized that high maternal dietary niacin intake during pregnancy, especially in combination with a high-fat diet (HFD) would increase infant adiposity. Methods We included 1040 participants from a pre-birth cohort of mother-infant pairs. Maternal diet was assessed using multiple 24-hour dietary recalls. HFD was defined as ≥30% of calories from fat and ≥12% of fat calories from saturated fat. Neonatal body composition (% fat mass [%FM], fat mass [FM], fat-free mass [FFM]) was measured by PEAPOD. We used multivariate regression to assess the joint effect of maternal dietary niacin and maternal HFD on neonatal body composition. Results Dietary niacin was not associated with neonatal body composition, and maternal HFD did not modify this finding. However, maternal HFD was independently associated with %FM (β = 0.8 [0.1, 1.4]%, p < 0.01] and FM (β = 32.4 [6.7, 58.0] g, p < 0.01). Conclusions for Practice Our results suggest that a HFD during pregnancy may increase infant adiposity, therefore supporting the need for improved diet counseling of pregnant women at both the clinical and community levels.

Amplification and propagation of interleukin-1β signaling by murine brain endothelial and glial cells

BACKGROUND

During acute infections and chronic illnesses, the pro-inflammatory cytokine interleukin-1β (IL-1β) acts within the brain to elicit metabolic derangements and sickness behaviors. It is unknown which cells in the brain are the proximal targets for IL-1β with respect to the generation of these illness responses. We performed a series of in vitro experiments to (1) investigate which brain cell populations exhibit inflammatory responses to IL-1β and (2) examine the interactions between different IL-1β-responsive cell types in various co-culture combinations.

METHODS

We treated primary cultures of murine brain microvessel endothelial cells (BMEC), astrocytes, and microglia with PBS or IL-1β, and then performed qPCR to measure inflammatory gene expression or immunocytochemistry to evaluate nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) activation. To evaluate whether astrocytes and/or BMEC propagate inflammatory signals to microglia, we exposed microglia to astrocyte-conditioned media and co-cultured endothelial cells and glia in transwells. Treatment groups were compared by Student's t tests or by ANOVA followed by Bonferroni-corrected t tests.

RESULTS

IL-1β increased inflammatory gene expression and NF-κB activation in primary murine-mixed glia, enriched astrocyte, and BMEC cultures. Although IL-1β elicited minimal changes in inflammatory gene expression and did not induce the nuclear translocation of NF-κB in isolated microglia, these cells were more robustly activated by IL-1β when co-cultured with astrocytes and/or BMEC. We observed a polarized endothelial response to IL-1β, because the application of IL-1β to the abluminal endothelial surface produced a more complex microglial inflammatory response than that which occurred following luminal IL-1β exposure.

CONCLUSIONS

Inflammatory signals are detected, amplified, and propagated through the CNS via a sequential and reverberating signaling cascade involving communication between brain endothelial cells and glia. We propose that the brain's innate immune response differs depending upon which side of the blood-brain barrier the inflammatory stimulus arises, thus allowing the brain to respond differently to central vs. peripheral inflammatory insults.

Beneficial effects of exercise on offspring obesity and insulin resistance are reduced by maternal high-fat diet

SCOPE

We investigated the long-term effects of maternal high-fat consumption and post-weaning exercise on offspring obesity susceptibility and insulin resistance.

METHODS

C57BL/6J dams were fed either a high-fat (HFD, 40% kcal fat) or low-fat (LFD, 10% kcal fat) semi-synthetic diet during pregnancy and lactation. After weaning, male offspring of both maternal diet groups (mLFD; mHFD) received a LFD. At week 7, half of the mice got access to a running wheel (+RW) as voluntary exercise training. To induce obesity, all offspring groups (mLFD +/-RW and mHFD +/-RW) received HFD from week 15 until week 25.

RESULTS

Compared to mLFD, mHFD offspring were more prone to HFD-induced body fat gain and exhibited an increased liver mass which was not due to increased hepatic triglyceride levels. RW improved the endurance capacity in mLFD, but not in mHFD offspring. Additionally, mHFD offspring +RW exhibited higher plasma insulin levels during glucose tolerance test and an elevated basal pancreatic insulin production compared to mLFD offspring.

CONCLUSION

Taken together, maternal HFD reduced offspring responsiveness to the beneficial effects of voluntary exercise training regarding the improvement of endurance capacity, reduction of fat mass gain, and amelioration of HFD-induced insulin resistance.

Parental High-Fat Diet Promotes Inflammatory and Senescence-Related Changes in Prostate

Background. Obesity and dietary habits are associated with increased incidences of aging-related prostatic diseases. The present study was aimed to investigate transgenerational effects of chronic high-fat diet (HFD) feeding on inflammation and senescence-related changes in prostate. Methods. Sprague-Dawley rats were kept on either normal or HFD one. Senescence-associated β-galactosidase (SA β-gal) activity, inflammation, and cellular proliferation were determined in the prostate. Results. Increased SA β-gal activity, expression of p53, and cell proliferation marker PCNA were observed in ventral prostate of HFD-fed rats. Immunostaining for p53 and PCNA revealed that the p53 immunopositive cells were primarily in stroma while PCNA immunopositive cells were epithelial cells. An increase in expression of cycloxygenase-2 (COX-2) and phosphorylation of nuclear factor-kappa B (NF-kB) was observed in prostate of weaning pups HFD-fed parents. However, in adult pups, irrespective of dietary habit, a significant increase in the expression of COX-2, PCNA, phosphorylation of NF-kB, infiltration of inflammatory cells, and SA β-gal activity was observed. Conclusions. Present investigation reports that HFD feeding promotes accumulation of p53 expressing cells, proliferation of epithelial cells, and senescence-related changes in prostate. Further, parental HFD-feeding upholds inflammatory, proliferative, and senescence-related changes in prostate of pups.

Maternal Western diet increases adiposity even in male offspring of obesity-resistant rat dams: early endocrine risk markers

Maternal overnutrition or associated complications putatively mediate the obesogenic effects of perinatal high-fat diet on developing offspring. Here, we tested the hypothesis that a Western diet developmental environment increases adiposity not only in male offspring from obesity-prone (DIO) mothers, but also in those from obesity-resistant (DR) dams, implicating a deleterious role for the Western diet per se. Selectively bred DIO and DR female rats were fed chow (17% kcal fat) or Western diet (32%) for 54 days before mating and, thereafter, through weaning. As intended, despite chow-like caloric intake, Western diet increased prepregnancy weight gain and circulating leptin levels in DIO, but not DR, dams. Yet, in both genotypes, maternal Western diet increased the weight and adiposity of preweanlings, as early as in DR offspring, and increased plasma leptin, insulin, and adiponectin of weanlings. Although body weight normalized with chow feeding during adolescence, young adult Western diet offspring subsequently showed decreased energy expenditure and, in DR offspring, decreased lipid utilization as a fuel substrate. By mid-adulthood, maternal Western diet DR offspring ate more chow, weighed more, and were fatter than controls. Thus, maternal Western diet covertly programmed increased adiposity in childhood and adulthood, disrupted relations of energy regulatory hormones with body fat, and decreased energy expenditure in offspring of lean, genetically obesity-resistant mothers. Maternal Western diet exposure alone, without maternal obesity or overnutrition, can promote offspring weight gain.

Nicotinamide Promotes Adipogenesis in Umbilical Cord-Derived Mesenchymal Stem Cells and Is Associated with Neonatal Adiposity: The Healthy Start BabyBUMP Project

The cellular mechanisms whereby excess maternal nutrition during pregnancy increases adiposity of the offspring are not well understood. However, nicotinamide (NAM), a fundamental micronutrient that is important in energy metabolism, has been shown to regulate adipogenesis through inhibition of SIRT1. Here we tested three novel hypotheses: 1) NAM increases the adipogenic response of human umbilical cord tissue-derived mesenchymal stem cells (MSCs) through a SIRT1 and PPARγ pathway; 2) lipid potentiates the NAM-enhanced adipogenic response; and 3) the adipogenic response to NAM is associated with increased percent fat mass (%FM) among neonates. MSCs were derived from the umbilical cord of 46 neonates born to non-obese mothers enrolled in the Healthy Start study. Neonatal %FM was measured using air displacement plethysmography (Pea Pod) shortly after birth. Adipogenic differentiation was induced for 21 days in the 46 MSC sets under four conditions, +NAM (3mM)/-lipid (200 μM oleate/palmitate mix), +NAM/+lipid, -NAM/+lipid, and vehicle-control (-NAM/-lipid). Cells incubated in the presence of NAM had significantly higher PPARγ protein (+24%, p <0.01), FABP4 protein (+57%, p <0.01), and intracellular lipid content (+51%, p <0.01). Lipid did not significantly increase either PPARγ protein (p = 0.98) or FABP4 protein content (p = 0.82). There was no evidence of an interaction between NAM and lipid on adipogenic response of PPARγ or FABP4 protein (p = 0.99 and p = 0.09). In a subset of 9 MSC, SIRT1 activity was measured in the +NAM/-lipid and vehicle control conditions. SIRT1 enzymatic activity was significantly lower (-70%, p <0.05) in the +NAM/-lipid condition than in vehicle-control. In a linear model with neonatal %FM as the outcome, the percent increase in PPARγ protein in the +NAM/-lipid condition compared to vehicle-control was a significant predictor (β = 0.04, 95% CI 0.01-0.06, p <0.001). These are the first data to support that chronic NAM exposure potentiates adipogenesis in human MSCs in-vitro, and that this process involves PPARγ and SIRT1.

A short-term transition from a high-fat diet to a normal-fat diet before pregnancy exacerbates female mouse offspring obesity

BACKGROUND/OBJECTIVES

Recent findings have highlighted the detrimental influence of maternal overnutrition and obesity on fetal development and early life development. However, there are no evidence-based guidelines regarding the optimal strategy for dietary intervention before pregnancy.

SUBJECTS/METHODS

We used a murine model to study whether switching from a high-fat (HF) diet to a normal-fat (NF) diet (H1N group) 1 week before pregnancy could lead to in utero reprogramming of female offspring obesity; comparator groups were offspring given a consistent maternal HF group or NF group until weaning. After weaning, all female offspring were given the HF diet for either 9 or 12 weeks before being killed humanely.

RESULTS

H1N treatment did not result in maternal weight loss before pregnancy. NF offsprings were neither obese nor glucose intolerant during the entire experimental period. H1N offsprings were most obese after the 12-week postweaning HF diet and displayed glucose intolerance earlier than HF offsprings. Our mechanistic study showed reduced adipocyte insulin receptor substrate 1 (IRS1) and hepatic IRS2 expression and increased adipocyte p-Ser(636/639) and p-Ser(612) of H1N or HF offspring compared with that in the NF offspring. Among all groups, the H1N offspring had lowest level of IRS1 and the highest levels of p-Ser(636/639) and p-Ser(612) in gonadal adipocyte. In addition, the H1N offspring further reduced the expression of Glut4 and Glut2, vs those of the HF offspring, which was lower compared with the NF offspring. There were also enhanced expression of genes inhibiting glycogenesis and decreased hepatic glycogen in H1N vs HF or NF offspring. Furthermore, we showed extremely higher expression of lipogenesis and adipogenesis genes in gonadal adipocytes of H1N offspring compared with all other groups.

CONCLUSIONS

Our results suggest that a transition from an HF diet to an NF diet shortly before pregnancy, without resulting in maternal weight loss, is not necessarily beneficial and may have deleterious effects on offspring.

Effects of Maternal Obesity on Fetal Programming: Molecular Approaches

Maternal obesity has become a worldwide epidemic. Obesity and a high-fat diet have been shown to have deleterious effects on fetal programming, predisposing offspring to adverse cardiometabolic and neurodevelopmental outcomes. Although large epidemiological studies have shown an association between maternal obesity and adverse outcomes for offspring, the underlying mechanisms remain unclear. Molecular approaches have played a key role in elucidating the mechanistic underpinnings of fetal malprogramming in the setting of maternal obesity. These approaches include, among others, characterization of epigenetic modifications, microRNA expression, the gut microbiome, the transcriptome, and evaluation of specific mRNA expression via quantitative reverse transcription polmerase chain reaction (RT-qPCR) in fetuses and offspring of obese females. This work will review the data from animal models and human fluids/cells regarding the effects of maternal obesity on fetal and offspring neurodevelopment and cardiometabolic outcomes, with a particular focus on molecular approaches.

Maternal High-Fat Feeding Increases Placental Lipoprotein Lipase Activity by Reducing SIRT1 Expression in Mice

This study investigated how maternal overnutrition and obesity regulate expression and activation of proteins that facilitate lipid transport in the placenta. To create a maternal overnutrition and obesity model, primiparous C57BL/6 mice were fed a high-fat (HF) diet throughout gestation. Fetuses from HF-fed dams had significantly increased serum levels of free fatty acid and body fat. Despite no significant difference in placental weight, lipoprotein lipase (LPL) protein levels and activity were remarkably elevated in placentas from HF-fed dams. Increased triglyceride content and mRNA levels of CD36, VLDLr, FABP3, FABPpm, and GPAT2 and -3 were also found in placentas from HF-fed dams. Although both peroxisome proliferator-activated receptor-γ (PPARγ) and CCAAT/enhancer binding protein-α protein levels were significantly increased in placentas of the HF group, only PPARγ exhibited a stimulative effect on LPL expression in cultured JEG-3 human trophoblasts. Maternal HF feeding remarkably decreased SIRT1 expression in placentas. Through use of an SIRT1 activator and inhibitor and cultured trophoblasts, an inhibitory effect of SIRT1 on LPL expression was demonstrated. We also found that SIRT1 suppresses PPARγ expression in trophoblasts. Most importantly, inhibition of PPARγ abolished the SIRT1-mediated regulatory effect on LPL expression. Together, these results indicate that maternal overnutrition induces LPL expression in trophoblasts by reducing the inhibitory effect of SIRT1 on PPARγ.

The role of chicken ovalbumin upstream promoter transcription factor II in the regulation of hepatic fatty acid oxidation and gluconeogenesis in newborn mice

Chicken ovalbumin upstream promoter transcription factor II (COUP-TFII) is an orphan nuclear receptor involved in the control of numerous functions in various organs (organogenesis, differentiation, metabolic homeostasis, etc.). The aim of the present work was to characterize the regulation and contribution of COUP-TFII in the control of hepatic fatty acid and glucose metabolisms in newborn mice. Our data show that postnatal increase in COUP-TFII mRNA levels is enhanced by glucagon (via cAMP) and PPARα. To characterize COUP-TFII function in the liver of suckling mice, we used a functional (dominant negative form; COUP-TFII-DN) and a genetic (shRNA) approach. Adenoviral COUP-TFII-DN injection induces a profound hypoglycemia due to the inhibition of gluconeogenesis and fatty acid oxidation secondarily to reduced PEPCK, Gl-6-Pase, CPT I, and mHMG-CoA synthase gene expression. Using the crossover plot technique, we show that gluconeogenesis is inhibited at two different levels: 1) pyruvate carboxylation and 2) trioses phosphate synthesis. This could result from a decreased availability in fatty acid oxidation arising cofactors such as acetyl-CoA and reduced equivalents. Similar results are observed using the shRNA approach. Indeed, when fatty acid oxidation is rescued in response to Wy-14643-induced PPARα target genes (CPT I and mHMG-CoA synthase), blood glucose is normalized in COUP-TFII-DN mice. In conclusion, this work demonstrates that postnatal increase in hepatic COUP-TFII gene expression is involved in the regulation of liver fatty acid oxidation, which in turn sustains an active hepatic gluconeogenesis that is essential to maintain an appropriate blood glucose level required for newborn mice survival.

Maternal intake of fat in pregnancy and offspring metabolic health - A prospective study with 20 years of follow-up

BACKGROUND

Maternal fat intake during pregnancy in relation to offspring metabolic outcomes has been studied primarily in animal models, yet little is known about the association in humans. The aim of this study was to examine the association of total and subtype of fat consumption in pregnancy with anthropometric measures and biomarkers of adiposity and glucose metabolism in the offspring.

METHODS

A source population was 965 Danish pregnant women recruited in 1988-1989 with offspring follow-up at 20 years. Information on fat intake was collected in the 30(th) week of gestation, and we subdivided fat according to saturated (SFA), monounsaturated (MUFA), and polyunsaturated (PUFA) fat. Offspring body mass index (BMI) and waist circumference (WC) were recorded at follow-up (n = 670-678), and biomarkers were quantified in a subset (n = 443) of participants. Multivariable linear and log-binomial regression were used to calculate effect estimates and 95% CI for a 1:1%energy substitution of carbohydrates for fat.

RESULTS

The mean (standard deviation) BMI was 22.1 (3.3) and 22.8 (2.9) kg/m(2) in female and male offspring, respectively. The median (10th to 90th percentile) of maternal fat intake was 31% of energy [23,39]. We found no overall associations for maternal fat intake with female offspring anthropometry. However, for male offspring higher intake of MUFA during pregnancy was associated with higher insulin levels at 20 years (Q4 vs. Q1: %Δ: 37, 95% CI: 1, 86) accompanied by a non-significant 3.6 (95% CI: -1.1, 8.2) cm increase in WC. High maternal total fat intake (>=35% energy) was also associated with higher BMI (0.9, 95% CI: 0.2, 1.6) and WC (4.0, 95% CI: 1.6, 2.3) among male offspring.

CONCLUSIONS

A high fat diet during pregnancy may increase adiposity in adult male offspring. We surmise that maternal MUFA intake during this time included both MUFA and trans fat misclassified as MUFA, and that the associations observed may be more reflective of the latter exposure.

Trans and interesterified fat and palm oil during the pregnancy and lactation period inhibit the central anorexigenic action of insulin in adult male rat offspring

Palm oil and interesterified fat have been used to replace partially hydrogenated fats, rich in trans isomers, in processed foods. This study investigated whether the maternal consumption of normolipidic diets containing these lipids affects the insulin receptor and Akt/protein kinase B (PKB) contents in the hypothalamus and the hypophagic effect of centrally administered insulin in 3-month-old male offspring. At 90 days, the intracerebroventricular injection of insulin decreased 24-h feeding in control rats but not in the palm, interesterified or trans groups. The palm group exhibited increases in the insulin receptor content of 64 and 69 % compared to the control and trans groups, respectively. However, the quantifications of PKB did not differ significantly across groups. We conclude that the intake of trans fatty acid substitutes during the early perinatal period affects food intake regulation in response to centrally administered insulin in the young adult offspring; however, the underlying mechanisms remain unclear.

The intrauterine and nursing period is a window of susceptibility for development of obesity and intestinal tumorigenesis by a high fat diet in Min/+ mice as adults

We studied how obesogenic conditions during various life periods affected obesity and intestinal tumorigenesis in adult C57BL/6J-Min (multiple intestinal neoplasia)/+ mice. The mice were given a 10% fat diet throughout life (negative control) or a 45% fat diet in utero, during nursing, during both in utero and nursing, during adult life, or during their whole life-span, and terminated at 11 weeks for tumorigenesis (Min/+) or 23 weeks for obesogenic effect (wild-type). Body weight at 11 weeks was increased after a 45% fat diet during nursing, during both in utero and nursing, and throughout life, but had normalized at 23 weeks. In the glucose tolerance test, the early exposure to a 45% fat diet in utero, during nursing, or during both in utero and nursing, did not affect blood glucose, whereas a 45% fat diet given to adults or throughout life did. However, a 45% fat diet during nursing or during in utero and nursing increased the number of small intestinal tumors. So did exposures to a 45% fat diet in adult life or throughout life, but without increasing the tumor numbers further. The intrauterine and nursing period is a window of susceptibility for dietary fat-induced obesity and intestinal tumor development.

Maternal high-fat diet and obesity compromise fetal hematopoiesis

OBJECTIVE

Recent evidence indicates that the adult hematopoietic system is susceptible to diet-induced lineage skewing. It is not known whether the developing hematopoietic system is subject to metabolic programming via in utero high-fat diet (HFD) exposure, an established mechanism of adult disease in several organ systems. We previously reported substantial losses in offspring liver size with prenatal HFD. As the liver is the main hematopoietic organ in the fetus, we asked whether the developmental expansion of the hematopoietic stem and progenitor cell (HSPC) pool is compromised by prenatal HFD and/or maternal obesity.

METHODS

We used quantitative assays, progenitor colony formation, flow cytometry, transplantation, and gene expression assays with a series of dietary manipulations to test the effects of gestational high-fat diet and maternal obesity on the day 14.5 fetal liver hematopoietic system.

RESULTS

Maternal obesity, particularly when paired with gestational HFD, restricts physiological expansion of fetal HSPCs while promoting the opposing cell fate of differentiation. Importantly, these effects are only partially ameliorated by gestational dietary adjustments for obese dams. Competitive transplantation reveals compromised repopulation and myeloid-biased differentiation of HFD-programmed HSPCs to be a niche-dependent defect, apparent in HFD-conditioned male recipients. Fetal HSPC deficiencies coincide with perturbations in genes regulating metabolism, immune and inflammatory processes, and stress response, along with downregulation of genes critical for hematopoietic stem cell self-renewal and activation of pathways regulating cell migration.

CONCLUSIONS

Our data reveal a previously unrecognized susceptibility to nutritional and metabolic developmental programming in the fetal HSPC compartment, which is a partially reversible and microenvironment-dependent defect perturbing stem and progenitor cell expansion and hematopoietic lineage commitment.

The aetiology of obesity beyond eating more and exercising less

Although recent increases in availability of energy dense, processed foods and reductions in institutionally driven physical activity have created an environment that is permissible for obesity to occur, several other factors may contribute to the development of obesity in this context. We review evidence for eleven such factors: endocrine disruptors, intrauterine effects, epigenetics, maternal age, differential fecundity and assortative mating by body mass index, microorganisms, reduction in variability of ambient temperatures, smoking cessation, sleep debt, and pharmaceutical iatrogenesis. Evidence for the role of endocrine disruptors, microorganisms, ambient temperatures, sleep and reproductive factors is accumulating, but additional research is needed to confirm the causative role of these factors in human obesity. However, the role of certain pharmaceuticals and smoking cessation in development of human obesity is clear. Practice points for consideration and future research needed are highlighted for each factor.

Lipotoxicity and the role of maternal nutrition

Intrauterine malnutrition predisposes the offspring towards the development of type 2 diabetes and cardiovascular disease. To explain this association, the Developmental Origins of Health and Disease hypothesis was introduced, meaning that subtle environmental changes during embryonic and foetal development can influence post-natal physiological functions. Different mechanisms, including epigenetics, are thought to be involved in this foetal programming, but the link between epigenetics and disease is missing. There is increasing evidence that ectopic lipid accumulation and/or lipotoxicity is induced by foetal programming. The aim of this review is to provide insights into the mechanisms underlying lipotoxicity through programming, which contributes to the increase in hepatic and cardiac metabolic risk.

Maternal high-fat diet alters expression of pathways of growth, blood supply and arachidonic acid in rat placenta

The high fat content in Western diets probably affects placental function during pregnancy with potential consequences for the offspring in the short and long term. The aim of the present study was to compare genome-wide placental gene expression between rat dams fed a high-fat diet (HFD) and those fed a control diet for 3 weeks before conception and during gestation. Gene expression was measured by microarray and pathway analysis was performed. Gene expression differences were replicated by real-time PCR and protein expression was assessed by Western blot analysis. Placental and fetal weights at E17.25 were not altered by exposure to the maternal HFD. Gene pathways targeting placental growth, blood supply and chemokine signalling were up-regulated in the placentae of dams fed the HFD. The up-regulation in messenger RNA expression for five genes Ptgs2 (fatty acid cyclo-oxidase 2; COX2), Limk1 (LIM domain kinase 1), Pla2g2a (phospholipase A2), Itga1 (integrin α-1) and Serpine1 was confirmed by real-time PCR. Placental protein expression for COX2 and LIMK was also increased in HFD-fed dams. In conclusion, maternal HFD feeding alters placental gene expression patterns of placental growth and blood supply and specifically increases the expression of genes involved in arachidonic acid and PG metabolism. These changes indicate a placental response to the altered maternal metabolic environment.

Maternal high fat feeding does not have long-lasting effects on body composition and bone health in female and male Wistar rat offspring at young adulthood

High fat diets adversely affect body composition, bone mineral and strength, and alter bone fatty acid composition. It is unclear if maternal high fat (HF) feeding permanently alters offspring body composition and bone health. Female rats were fed control (CON) or HF diet for 10 weeks, bred, and continued their diets throughout pregnancy and lactation. Male and female offspring were studied at weaning and 3 months, following consumption of CON diet. At weaning, but not 3 months of age, male and female offspring from dams fed HF diet had lower lean mass and higher fat and bone mass, and higher femur bone mineral density (females only) than offspring of dams fed CON diet. Male and female offspring femurs from dams fed HF diet had higher monounsaturates and lower n6 polyunsaturates at weaning than offspring from dams fed CON diet, where females from dams fed HF diet had higher saturates and lower n6 polyunsaturates at 3 months of age. There were no differences in strength of femurs or lumbar vertebrae at 3 months of age in either male or female offspring. In conclusion, maternal HF feeding did not permanently affect body composition and bone health at young adulthood in offspring.

Nutritional manipulations in the perinatal period program adipose tissue in offspring

Epidemiological studies demonstrated initially that maternal undernutrition results in low birth weight with increased risk for long-lasting energy balance disorders. Maternal obesity and diabetes associated with high birth weight, excessive nutrition in neonates, and rapid catchup growth also increase the risk of adult-onset obesity. As stated by the Developmental Origin of Health and Disease concept, nutrient supply perturbations in the fetus or neonate result in long-term programming of individual body weight set point. Adipose tissue is a key fuel storage unit involved mainly in the maintenance of energy homeostasis. Studies in numerous animal models have demonstrated that the adipose tissue is the focus of developmental programming events in a sex- and depot-specific manner. In rodents, adipose tissue development is particularly active during the perinatal period, especially during the last week of gestation and during early postnatal life. In contrast to rodents, this process essentially takes place before birth in bigger mammals. Despite these different developmental time windows, altricial and precocial species share several mechanisms of adipose tissue programming. Offspring from malnourished dams present adipose tissue with a series of alterations: impaired glucose uptake, insulin and leptin resistance, low-grade inflammation, modified sympathetic activity with reduced noradrenergic innervations, and thermogenesis. These modifications reprogram adipose tissue metabolism by changing fat distribution and composition and by enhancing adipogenesis, predisposing the offspring to fat accumulation. Subtle adipose tissue circadian rhythm changes are also observed. Inappropriate hormone levels, modified tissue sensitivity (especially glucocorticoid system), and epigenetic mechanisms are key factors for adipose tissue programming during the perinatal period.

High-saturated fat-sucrose feeding affects lactation energetics in control mice and mice selectively bred for high wheel-running behavior

Feeding a diet high in fat and sucrose (HFS) during pregnancy and lactation is known to increase susceptibility to develop metabolic derangements later in life. A trait for increased behavioral activity may oppose these effects, since this would drain energy from milk produced to be made available to the offspring. To investigate these interactions, we assessed several components of behavioral energetics during lactation in control mice (C) and in mice of two lines selectively bred for high wheel-running activity (S1, S2) subjected to a HFS diet or a low-fat (LF) diet. Energy intake, litter growth, and milk energy output at peak lactation (MEO; assessed by subtracting maternal metabolic rate from energy intake) were elevated in HFS-feeding dams across all lines compared with the LF condition, an effect that was particularly evident in the S dams. This effect was not preceded by improved lactation behaviors assessed between postnatal days 1 and 7 (PND 1-7). In fact, S1 dams had less high-quality nursing, and S2 dams showed poorer pup retrieval than C dams during PND 1-7, and S dams had generally higher levels of physical activity at peak lactation. These data demonstrate that HFS feeding increases MEO underlying increased litter and pup growth, particularly in mice with a trait for increased behavioral physical activity.

Animal models of in utero exposure to a high fat diet: a review

The incidence of metabolic disease, including type 2 diabetes and obesity, has increased to epidemic levels in recent years. A growing body of evidence suggests that the intrauterine environment plays a key role in the development of metabolic disease in offspring. Among other perturbations in early life, alteration in the provision of nutrients has profound and lasting effects on the long term health and well being of offspring. Rodent and non-human primate models provide a means to understand the underlying mechanisms of this programming effect. These different models demonstrate converging effects of a maternal high fat diet on insulin and glucose metabolism, energy balance, cardiovascular function and adiposity in offspring. Furthermore, evidence suggests that the early life environment can result in epigenetic changes that set the stage for alterations in key pathways of metabolism that lead to type 2 diabetes or obesity. Identifying and understanding the causal factors responsible for this metabolic dysregulation is vital to curtailing these epidemics. This article is part of a Special Issue entitled: Modulation of Adipose Tissue in Health and Disease.

Early growth response protein-1 mediates lipotoxicity-associated placental inflammation: role in maternal obesity

Obesity is associated with low-grade chronic inflammation, which contributes to cellular dysfunction promoting metabolic disease. Obesity during pregnancy leads to a proinflammatory milieu in the placenta; however, the underlying causes for obesity-induced placental inflammation remain unclear. Here, we examine the mechanisms by which saturated fatty acids and inflammatory cytokines induce inflammation in placental trophoblasts. We conducted global transcriptomic profiling in BeWo cells following palmitate and/or TNFα treatment and gene/protein expression analyses of MAPK pathways and characterized downstream transcription factors directly regulating inflammatory cytokines. Microarray analysis revealed increased expression of genes regulating inflammation, stress response, and immediate early response in cytotrophoblasts in response to palmitic acid (PA), TNFα, or a combination of both (PA + TNFα). Both gene ontology and gene set enrichment analysis revealed MAPK and EGR-1 signaling to be upregulated in BeWo cells, which was confirmed via immunoblotting. Importantly, activation of JNK signaling was necessary for increased proinflammatory cytokine (IL-6, TNFα, and IL-8) and EGR1 mRNA. Consistent with the requirement of JNK signaling, ChIP analysis confirmed the recruitment of c-Jun and other MAPK-responsive immediate early factors on the EGR1 promoter. Moreover, recruitment of EGR-1 on cytokine promoters (IL-6, TNFα, and IL-8) and an impaired proinflammatory response following knockdown of EGR-1 suggested it as a central component of the mechanism facilitating inflammatory gene expression. Finally, akin to in vitro findings, term placenta from obese women also had both increased JNK and p38 signaling and greater EGR-1 protein relative to lean women. Our results demonstrate that lipotoxic insults induce inflammation in placental cells via activation of JNK/EGR-1 signaling.

Transgenic increase in N-3/n-6 Fatty Acid ratio reduces maternal obesity-associated inflammation and limits adverse developmental programming in mice

Maternal and pediatric obesity has risen dramatically over recent years, and is a known predictor of adverse long-term metabolic outcomes in offspring. However, which particular aspects of obese pregnancy promote such outcomes is less clear. While maternal obesity increases both maternal and placental inflammation, it is still unknown whether this is a dominant mechanism in fetal metabolic programming. In this study, we utilized the Fat-1 transgenic mouse to test whether increasing the maternal n-3/n-6 tissue fatty acid ratio could reduce the consequences of maternal obesity-associated inflammation and thereby mitigate downstream developmental programming. Eight-week-old WT or hemizygous Fat-1 C57BL/6J female mice were placed on a high-fat diet (HFD) or control diet (CD) for 8 weeks prior to mating with WT chow-fed males. Only WT offspring from Fat-1 mothers were analyzed. WT-HFD mothers demonstrated increased markers of infiltrating adipose tissue macrophages (P<0.02), and a striking increase in 12 serum pro-inflammatory cytokines (P<0.05), while Fat1-HFD mothers remained similar to WT-CD mothers, despite equal weight gain. E18.5 Fetuses from WT-HFD mothers had larger placentas (P<0.02), as well as increased placenta and fetal liver TG deposition (P<0.01 and P<0.02, respectively) and increased placental LPL TG-hydrolase activity (P<0.02), which correlated with degree of maternal insulin resistance (r = 0.59, P<0.02). The placentas and fetal livers from Fat1-HFD mothers were protected from this excess placental growth and fetal-placental lipid deposition. Importantly, maternal protection from excess inflammation corresponded with improved metabolic outcomes in adult WT offspring. While the offspring from WT-HFD mothers weaned onto CD demonstrated increased weight gain (P<0.05), body and liver fat (P<0.05 and P<0.001, respectively), and whole body insulin resistance (P<0.05), these were prevented in WT offspring from Fat1-HFD mothers. Our results suggest that reducing excess maternal inflammation may be a promising target for preventing adverse fetal metabolic outcomes in pregnancies complicated by maternal obesity.

Missense mutation in mouse GALC mimics human gene defect and offers new insights into Krabbe disease

Krabbe disease is a devastating pediatric leukodystrophy caused by mutations in the galactocerebrosidase (GALC) gene. A significant subset of the infantile form of the disease is due to missense mutations that result in aberrant protein production. The currently used mouse model, twitcher, has a nonsense mutation not found in Krabbe patients, although it is similar to the human 30 kb deletion in abrogating GALC expression. Here, we identify a spontaneous mutation in GALC, GALCtwi-5J, that precisely matches the E130K missense mutation in patients with infantile Krabbe disease. GALCtwi-5J homozygotes show loss of enzymatic activity despite normal levels of precursor protein, and manifest a more severe phenotype than twitcher, with half the life span. Although neuropathological hallmarks such as gliosis, globoid cells and psychosine accumulation are present throughout the nervous system, the CNS does not manifest significant demyelination. In contrast, the PNS is severely hypomyelinated and lacks large diameter axons, suggesting primary dysmyelination, rather than a demyelinating process. Our data indicate that early demise is due to mechanisms other than myelin loss and support an important role for neuroinflammation in Krabbe disease progression. Furthermore, our results argue against a causative relationship between psychosine accumulation, white matter loss and gliosis.

Perinatal epigenetic determinants of cognitive and metabolic disorders

Multiple cues from the environment of our indirect and immediate ancestors, which often persist throughout the prenatal period and adulthood, are shaping our phenotypes through either direct, parent-to-child influences, or transgenerational inheritance. These effects are due to gene-environment interactions, which are intended to be a predictive tool and a mechanism of quick adaptation to the environment, as compared with genetic variations that are inherited over many generations. In certain circumstances the influences induced by the gene-environment interactions can have deleterious effects upon the health status, in the context of a radical change in the environment that does not fit with the predicted conditions, via epigenetic alterations. Conversely the best fit to the expected environment might have a delayed aging process and a longer life span. This review will touch upon the Developmental Origins of Health and Disease (DoHAD) concept, while discussing recent advances in the understanding of metabolic and cognitive disruptions, with a focus on epigenetic factors, their transgenerational effects, and the consequences they might have upon the onset of chronic disease and premature exitus.

Biological determinants linking infant weight gain and child obesity: current knowledge and future directions

Childhood obesity rates have reached epidemic proportions. Excessive weight gain in infancy is associated with persistence of elevated weight status and later obesity. In this review, we make the case that weight gain in the first 6 mo is especially predictive of later obesity risk due to the metabolic programming that can occur early postpartum. The current state of knowledge regarding the biological determinants of excess infant weight gain is reviewed, with particular focus on infant feeding choice. Potential mechanisms by which different feeding approaches may program the metabolic profile of the infant, causing the link between early weight gain and later obesity are proposed. These mechanisms are likely highly complex and involve synergistic interactions between endocrine effects and factors that alter the inflammatory and oxidative stress status of the infant. Gaps in current knowledge are highlighted. These include a lack of data describing 1) what type of infant body fat distribution may impart risk and 2) how maternal metabolic dysfunction (obesity and/or diabetes) may affect milk composition and exert downstream effects on infant metabolism. Improved understanding and management of these early postnatal determinants of childhood obesity may have great impact on reducing its prevalence.