A maternal high-fat diet is accompanied by alterations in the fetal primate metabolome

Initiation of metformin in early pregnancy results in fetal bioaccumulation, growth restriction, and renal dysmorphology in a primate model

BACKGROUND

In recent years, pragmatic metformin use in pregnancy has stretched to include prediabetes mellitus, type 2 diabetes mellitus, gestational diabetes mellitus, and (most recently) preeclampsia. However, with its expanded use, concerns of unintended harm have been raised.

OBJECTIVE

This study developed an experimental primate model and applied ultrahigh performance liquid chromatography coupled to triple-quadrupole mass spectrometry for direct quantitation of maternal and fetal tissue metformin levels with detailed fetal biometry and histopathology.

STUDY DESIGN

Within 30 days of confirmed conception (defined as early pregnancy), 13 time-bred (timed-mated breeding) Rhesus dams with pregnancies designated for fetal necropsy were initiated on twice-daily human dose-equivalent 10 mg/kg metformin or vehicle control. Pregnant dams were maintained as pairs and fed either a control chow or 36% fat Western-style diet. Metformin or placebo vehicle control was delivered in various treats while the animals were separated via a slide. A cesarean delivery was performed at gestational day 145, and amniotic fluid and blood were collected, and the fetus and placenta were delivered. The fetus was immediately necropsied by trained primate center personnel. All fetal organs were dissected, measured, sectioned, and processed per clinical standards. Fluid and tissue metformin levels were assayed using validated ultrahigh performance liquid chromatography coupled to triple-quadrupole mass spectrometry in selected reaction monitoring against standard curves.

RESULTS

Among 13 pregnancies at gestational day 145 with fetal necropsy, 1 dam and its fetal tissues had detectable metformin levels despite being allocated to the vehicle control group (>1 μmol metformin/kg maternal weight or fetal or placental tissue), whereas a second fetus allocated to the vehicle control group had severe fetal growth restriction (birthweight of 248.32 g [<1%]) and was suspected of having a fetal congenital condition. After excluding these 2 fetal pregnancies from further analyses, 11 fetuses from dams initiated on either vehicle control (n=4: 3 female and 1 male fetuses) or 10 mg/kg metformin (n=7: 5 female and 2 male fetuses) were available for analyses. Among dams initiated on metformin at gestational day 30 (regardless of maternal diet), significant bioaccumulation within the fetal kidney (0.78-6.06 μmol/kg; mean of 2.48 μmol/kg), liver (0.16-0.73 μmol/kg; mean of 0.38 μmol/kg), fetal gut (0.28-1.22 μmol/kg; mean of 0.70 μmol/kg), amniotic fluid (0.43-3.33 μmol/L; mean of 1.88 μmol/L), placenta (0.16-1.00 μmol/kg; mean of 0.50 μmol/kg), fetal serum (0.00-0.66 μmol/L; mean of 0.23 μmol/L), and fetal urine (4.10-174.10 μmol/L; mean of 38.5 μmol/L) was observed, with fetal levels near biomolar equivalent to maternal levels (maternal serum: 0.18-0.86 μmol/L [mean of 0.46 μmol/L]; maternal urine: 42.60-254.00 μmol/L [mean of 149.30 μmol/L]). Western-style diet feeding neither accelerated nor reduced metformin bioaccumulations in maternal or fetal serum, urine, amniotic fluid, placenta, or fetal tissues. In these 11 animals, fetal bioaccumulation of metformin was associated with less fetal skeletal muscle (57% lower cross-sectional area of gastrocnemius) and decreased liver, heart, and retroperitoneal fat masses (P<.05), collectively driving lower delivery weight (P<.0001) without changing the crown-rump length. Sagittal sections of fetal kidneys demonstrated delayed maturation, with disorganized glomerular generations and increased cortical thickness. This renal dysmorphology was not accompanied by structural or functional changes indicative of renal insufficiency.

CONCLUSION

Our study demonstrates fetal bioaccumulation of metformin with associated fetal growth restriction and renal dysmorphology after maternal initiation of the drug within 30 days of conception in primates. Given these results and the prevalence of metformin use during pregnancy, additional investigation of any potential immediate and enduring effects of prenatal metformin use is warranted.

Maternal Western-style diet in nonhuman primates leads to offspring islet adaptations including altered gene expression and insulin hypersecretion

Maternal overnutrition is associated with increased susceptibility to type 2 diabetes in the offspring. Rodent models have shown that maternal overnutrition influences islet function in offspring. To determine whether maternal Western-style diet (WSD) alters prejuvenile islet function in a model that approximates that of human offspring, we utilized a well-characterized Japanese macaque model. We compared islet function from offspring exposed to WSD throughout pregnancy and lactation and weaned to WSD (WSD/WSD) compared with islets from offspring exposed only to postweaning WSD (CD/WSD) at 1 yr of age. WSD/WSD offspring islets showed increased basal insulin secretion and an exaggerated increase in glucose-stimulated insulin secretion, as assessed by dynamic ex vivo perifusion assays, relative to CD/WSD-exposed offspring. We probed potential mechanisms underlying insulin hypersecretion using transmission electron microscopy to evaluate β-cell ultrastructure, qRT-PCR to quantify candidate gene expression, and Seahorse assay to assess mitochondrial function. Insulin granule density, mitochondrial density, and mitochondrial DNA ratio were similar between groups. However, islets from WSD/WSD male and female offspring had increased expression of transcripts known to facilitate stimulus-secretion coupling and changes in the expression of cell stress genes. Seahorse assay revealed increased spare respiratory capacity in islets from WSD/WSD male offspring. Overall, these results show that maternal WSD feeding confers changes to genes governing insulin secretory coupling and results in insulin hypersecretion as early as the postweaning period. The results suggest a maternal diet leads to early adaptation and developmental programming in offspring islet genes that may underlie future β-cell dysfunction.NEW & NOTEWORTHY Programed adaptations in islets in response to maternal WSD exposure may alter β-cell response to metabolic stress in offspring. We show that islets from maternal WSD-exposed offspring hypersecrete insulin, possibly due to increased components of stimulus-secretion coupling. These findings suggest that islet hyperfunction is programed by maternal diet, and changes can be detected as early as the postweaning period in nonhuman primate offspring.

HSF1 is a driver of leukemia stem cell self-renewal in acute myeloid leukemia

Acute myeloid leukemia (AML) is maintained by self-renewing leukemic stem cells (LSCs). A fundamental problem in treating AML is that conventional therapy fails to eliminate LSCs, which can reinitiate leukemia. Heat shock transcription factor 1 (HSF1), a central regulator of the stress response, has emerged as an important target in cancer therapy. Using genetic Hsf1 deletion and a direct HSF1 small molecule inhibitor, we show that HSF1 is specifically required for the maintenance of AML, while sparing steady-state and stressed hematopoiesis. Mechanistically, deletion of Hsf1 dysregulates multifaceted genes involved in LSC stemness and suppresses mitochondrial oxidative phosphorylation through downregulation of succinate dehydrogenase C (SDHC), a direct HSF1 target. Forced expression of SDHC largely restores the Hsf1 ablation-induced AML developmental defect. Importantly, the growth and engraftment of human AML cells are suppressed by HSF1 inhibition. Our data provide a rationale for developing efficacious small molecules to specifically target HSF1 in AML.

Large1 gene transfer in older myd mice with severe muscular dystrophy restores muscle function and greatly improves survival

Muscular dystrophy is a progressive and ultimately lethal neuromuscular disease. Although gene editing and gene transfer hold great promise as therapies when administered before the onset of severe clinical symptoms, it is unclear whether these strategies can restore muscle function and improve survival in the late stages of muscular dystrophy. Largemyd/Largemyd (myd) mice lack expression of like-acetylglucosaminyltransferase-1 (Large1) and exhibit severe muscle pathophysiology, impaired mobility, and a markedly reduced life span. Here, we show that systemic delivery of AAV2/9 CMV Large1 (AAVLarge1) in >34-week-old myd mice with advanced disease restores matriglycan expression on dystroglycan, attenuates skeletal muscle pathophysiology, improves motor and respiratory function, and normalizes systemic metabolism, which collectively and markedly extends survival. Our results in a mouse model of muscular dystrophy demonstrate that skeletal muscle function can be restored, illustrating its remarkable plasticity, and that survival can be greatly improved even after the onset of severe muscle pathophysiology.

Maternal and early life exposures and their potential to influence development of the microbiome

At the dawn of the twentieth century, the medical care of mothers and children was largely relegated to family members and informally trained birth attendants. As the industrial era progressed, early and key public health observations among women and children linked the persistence of adverse health outcomes to poverty and poor nutrition. In the time hence, numerous studies connecting genetics ("nature") to public health and epidemiologic data on the role of the environment ("nurture") have yielded insights into the importance of early life exposures in relation to the occurrence of common diseases, such as diabetes, allergic and atopic disease, cardiovascular disease, and obesity. As a result of these parallel efforts in science, medicine, and public health, the developing brain, immune system, and metabolic physiology are now recognized as being particularly vulnerable to poor nutrition and stressful environments from the start of pregnancy to 3 years of age. In particular, compelling evidence arising from a diverse array of studies across mammalian lineages suggest that modifications to our metagenome and/or microbiome occur following certain environmental exposures during pregnancy and lactation, which in turn render risk of childhood and adult diseases. In this review, we will consider the evidence suggesting that development of the offspring microbiome may be vulnerable to maternal exposures, including an analysis of the data regarding the presence or absence of a low-biomass intrauterine microbiome.

Western-style diet consumption impairs maternal insulin sensitivity and glucose metabolism during pregnancy in a Japanese macaque model

The prevalence of maternal obesity is increasing in the United States. Offspring born to women with obesity or poor glycemic control have greater odds of becoming obese and developing metabolic disease later in life. Our group has utilized a macaque model to study the metabolic effects of consumption of a calorically-dense, Western-style diet (WSD; 36.3% fat) during pregnancy. Here, our objective was to characterize the effects of WSD and obesity, alone and together, on maternal glucose tolerance and insulin levels in dams during each pregnancy. Recognizing the collinearity of maternal measures, we adjusted for confounding factors including maternal age and parity. Based on intravenous glucose tolerance tests, dams consuming a WSD showed lower glucose area under the curve during first study pregnancies despite increased body fat percentage and increased insulin area under the curve. However, with (1) prolonged WSD feeding, (2) multiple diet switches, and/or (3) increasing age and parity, WSD was associated with increasingly higher insulin levels during glucose tolerance testing, indicative of insulin resistance. Our results suggest that prolonged or recurrent calorically-dense WSD and/or increased parity, rather than obesity per se, drive excess insulin resistance and metabolic dysfunction. These observations in a highly relevant species are likely of clinical and public health importance given the comparative ease of maternal dietary modifications relative to the low likelihood of successfully reversing obesity in the course of any given pregnancy.

Nutrition and Metabolic Adaptations in Physiological and Complicated Pregnancy: Focus on Obesity and Gestational Diabetes

Pregnancy offers a window of opportunity to program the future health of both mothers and offspring. During gestation, women experience a series of physical and metabolic modifications and adaptations, which aim to protect the fetus development and are closely related to both pre-gestational nutritional status and gestational weight gain. Moreover, pre-gestational obesity represents a challenge of treatment, and nowadays there are new evidence as regard its management, especially the adequate weight gain. Recent evidence has highlighted the determinant role of nutritional status and maternal diet on both pregnancy outcomes and long-term risk of chronic diseases, through a transgenerational flow, conceptualized by the Development Origin of Health and Diseases (Dohad) theory. In this review we will analyse the physiological and endocrine adaptation in pregnancy, and the metabolic complications, thus the focal points for nutritional and therapeutic strategies that we must early implement, virtually before conception, to safeguard the health of both mother and progeny. We will summarize the current nutritional recommendations and the use of nutraceuticals in pregnancy, with a focus on the management of pregnancy complicated by obesity and hyperglycemia, assessing the most recent evidence about the effects of ante-natal nutrition on the long-term, on either maternal health or metabolic risk of the offspring.

Maternal Malnutrition Affects Hepatic Metabolism through Decreased Hepatic Taurine Levels and Changes in HNF4A Methylation

Fetal programming implies that the maternal diet during pregnancy affects the long-term health of offspring. Although maternal diet influences metabolic disorders and non-alcoholic fatty liver disease in offspring, the hepatic mechanisms related to metabolites are still unknown. Here, we investigated the maternal diet-related alterations in metabolites and the biological pathway in male offspring at three months of age. Pregnant rats were exposed to 50% food restriction during the prenatal period or a 45% high-fat diet during the prenatal and postnatal periods. The male offspring exposed to food restriction and high-fat diets had lower birth weights than controls, but had a catch-up growth spurt at three months of age. Hepatic taurine levels decreased in both groups compared to controls. The decreased hepatic taurine levels in offspring affected excessive lipid accumulation through changes in hepatocyte nuclear factor 4 A methylation. Moreover, the alteration of gluconeogenesis in offspring exposed to food restriction was observed to a similar extent as that of offspring exposed to a high fat diet. These results indicate that maternal diet affects the dysregulation in hepatic metabolism through changes in taurine levels and HNF4A methylation, and predisposes the offspring to Type 2 diabetes and non-alcoholic fatty liver disease in later life.

Strength of nonhuman primate studies of developmental programming: review of sample sizes, challenges, and steps for future work

Nonhuman primate (NHP) studies are crucial to biomedical research. NHPs are the species most similar to humans in lifespan, body size, and hormonal profiles. Planning research requires statistical power evaluation, which is difficult to perform when lacking directly relevant preliminary data. This is especially true for NHP developmental programming studies, which are scarce. We review the sample sizes reported, challenges, areas needing further work, and goals of NHP maternal nutritional programming studies. The literature search included 27 keywords, for example, maternal obesity, intrauterine growth restriction, maternal high-fat diet, and maternal nutrient reduction. Only fetal and postnatal offspring studies involving tissue collection or imaging were included. Twenty-eight studies investigated maternal over-nutrition and 33 under-nutrition; 23 involved macaques and 38 baboons. Analysis by sex was performed in 19; minimum group size ranged from 1 to 8 (mean 4.7 ± 0.52, median 4, mode 3) and maximum group size from 3 to 16 (8.3 ± 0.93, 8, 8). Sexes were pooled in 42 studies; minimum group size ranged from 2 to 16 (mean 5.3 ± 0.35, median 6, mode 6) and maximum group size from 4 to 26 (10.2 ± 0.92, 8, 8). A typical study with sex-based analyses had group size minimum 4 and maximum 8 per sex. Among studies with sexes pooled, minimum group size averaged 6 and maximum 8. All studies reported some significant differences between groups. Therefore, studies with group sizes 3-8 can detect significance between groups. To address deficiencies in the literature, goals include increasing age range, more frequently considering sex as a biological variable, expanding topics, replicating studies, exploring intergenerational effects, and examining interventions.

The development and ecology of the Japanese macaque gut microbiome from weaning to early adolescence in association with diet

Previously we have shown that the Japanese macaque gut microbiome differs not by obesity per se, but rather in association with high-fat diet (HFD) feeding. This held true for both pregnant dams, as well as their 1-year-old offspring, even when weaned onto a control diet. Here we aimed to examine the stability of the gut microbiome over time and in response to maternal and postweaning HFD feeding from 6 months of age, and at 1 and 3 years of age. In both cross-sectional and longitudinal specimens, we performed analysis of the V4 hypervariable region of the 16S rRNA gene on anus swabs collected from pregnant dams and their juveniles at age 6 months to 3 years (n = 55). Extracted microbial DNA was subjected to 16S-amplicon-based metagenomic sequencing on the Illumina MiSeq platform. We initially identified 272 unique bacterial genera, and multidimensional scaling revealed samples to cluster by age and diet exposures. Dirichlet multinomial mixture modeling of microbiota abundances enabled identification of two predominant enterotypes to which samples sorted, characterized primarily by Treponema abundance, or lack thereof. Approximating the time of initial weaning (6 months), the Japanese macaque offspring microbiome underwent a significant state type transition which stabilized from 1 to 3 years of age. However, we also found the low abundance Treponema enterotype to be strongly associated with HFD exposure, be it during gestation/lactation or in the postweaning interval. Examination of taxonomic co-occurrences revealed samples within the low Treponema cluster were relatively permissive (allowing for increased interactions between microbiota) whereas samples within the high Treponema cluster were relatively exclusionary (suggesting decreased interactions amongst microbiota). Taken together, these findings suggest that Treponemes are keystone species in the developing gut microbiome of the gut, and susceptible to HFD feeding in their relative abundance.

High Fat Programming and Cardiovascular Disease

Programming is triggered through events during critical developmental phases that alter offspring health outcomes. High fat programming is defined as the maintenance on a high fat diet during fetal and/or early postnatal life that induces metabolic and physiological alterations that compromise health. The maternal nutritional status, including the dietary fatty acid composition, during gestation and/or lactation, are key determinants of fetal and postnatal development. A maternal high fat diet and obesity during gestation compromises the maternal metabolic state and, through high fat programming, presents an unfavorable intrauterine milieu for fetal growth and development thereby conferring adverse cardiac outcomes to offspring. Stressors on the heart, such as a maternal high fat diet and obesity, alter the expression of cardiac-specific factors that alter cardiac structure and function. The proper nutritional balance, including the fatty acid balance, particularly during developmental windows, are critical for maintaining cardiac structure, preserving cardiac function and enhancing the cardiac response to metabolic challenges.

Developmental Programming of Obesity and Diabetes in Mouse, Monkey, and Man in 2018: Where Are We Headed?

Childhood obesity and its comorbidities continue to accelerate across the globe. Two-thirds of pregnant women are obese/overweight, as are 20% of preschoolers. Gestational diabetes mellitus (GDM) is escalating, affecting up to 1 in 5 pregnant women. The field of developmental origins of health and disease has begun to move beyond associations to potential causal mechanisms for developmental programming. Evidence across species compellingly demonstrates that maternal obesity, diabetes, and Western-style diets create a long-lasting signature on multiple systems, including infant stem cells, the early immune system, and gut microbiota. Such exposures accelerate adipogenesis, disrupt mitochondrial metabolism, and impair energy sensing, affecting neurodevelopment, liver, pancreas, and skeletal muscle. Attempts to prevent developmental programming have met with very limited success. A challenging level of complexity is involved in how the host genome, metabolome, and microbiome throughout pregnancy and lactation increase the offspring's risk of metabolic diseases across the life span. Considerable gaps in knowledge include the timing of exposure(s) and permanence or plasticity of the response, encompassing effects from both maternal and paternal dysmetabolism. Basic, translational, and human intervention studies targeting pathways that connect diet, microbiota, and metabolism in mothers with obesity/GDM and their infants are a critical unmet need and present new challenges for disease prevention in the next generation.

Modulations in the offspring gut microbiome are refractory to postnatal synbiotic supplementation among juvenile primates

Background

We and others have previously shown that alterations in the mammalian gut microbiome are associated with diet, notably early life exposure to a maternal high fat diet (HFD). Here, we aimed to further these studies by examining alterations in the gut microbiome of juvenile Japanese macaques (Macaca fuscata) that were exposed to a maternal HFD, weaned onto a control diet, and later supplemented with a synbiotic comprised of psyllium seed and Enterococcus and Lactobacillus species.

Results

Eighteen month old offspring (n = 7) of 36% HFD fed dams were fed a control (14% fat) diet post weaning, then were synbiotic supplemented for 75 days and longitudinal stool and serum samples were obtained. All stool samples were subjected to 16S rRNA metagenomic sequencing, and microbiome profiles and serum lipids and triglycerides were compared to untreated, healthy age matched and diet matched controls (n = 7). Overall, 16S-based metagenomic analysis revealed that supplementation exerted minimal alterations to the gut microbiome including transient increased abundance of Lactobacillus species and decreased abundance of few bacterial genera, including Faecalibacterium and Anaerovibrio. However, serum lipid analysis revealed significant decreases in triglycerides, cholesterol, and LDL (p < 0.05). Nevertheless, supplemented juveniles challenged 4 months later were not protected from HFD-induced gut dysbiosis.

Conclusions

Synbiotic supplementation is temporally associated with alterations in the gut microbiome and host lipid profiles of juvenile Japanese macaques that were previously exposed to a maternal HFD. Despite these presumptive temporal benefits, a protective effect against later HFD-challenge gut dysbiosis was not observed.

Electronic supplementary material

The online version of this article (10.1186/s12866-018-1169-9) contains supplementary material, which is available to authorized users.

Bone marrow lympho-myeloid malfunction in obesity requires precursor cell-autonomous TLR4

Obesity, a prevalent condition in adults and children, impairs bone marrow (BM) function. However, the underlying mechanisms are unclear. Here, we show that obese mice exhibit poor emergency immune responses in a toll-like receptor 4 (TLR4)-dependent manner. Canonical myeloid genes (Csf1r, Spi1, Runx1) are enhanced, and lymphoid genes (Flt3, Tcf3, Ebf1) are reduced. Using adoptive transfer and mixed BM chimera approaches we demonstrate that myeloid>lymphoid bias arises after 6 weeks of high-fat diet and depends on precursor cell-autonomous TLR4. Further, lean mice exposed to the TLR4 ligand lipopolysaccharide (LPS) at doses similar to that detectable in obese serum recapitulates BM lympho-myeloid alterations. Together, these results establish a mechanistic contribution of BM cell-intrinsic TLR4 to obesity-driven BM malfunction and demonstrate the importance of LPS. Our findings raises important questions about the impact of maternal obesity and endotoxemia to fetal hematopoiesis, as fetal immune precursors are also sensitive to TLR4 signals.

Obesity can affect bone marrow cell differentiation and the generation of myeloid and lymphoid cells. Here, the authors show that diet and obesity, as well as low-dose lipopolysaccharide, can alter Toll-like receptor 4 signaling bone marrow cells to skew the myeloid-lymphoid homeostasis in mice.

Metabolic programming of the epigenome: host and gut microbial metabolite interactions with host chromatin

The mammalian gut microbiota has been linked to host developmental, immunologic, and metabolic outcomes. This collection of trillions of microbes inhabits the gut and produces a myriad of metabolites, which are measurable in host circulation and contribute to the pathogenesis of human diseases. The link between endogenous metabolite availability and chromatin regulation is a well-established and active area of investigation; however, whether microbial metabolites can elicit similar effects is less understood. In this review, we focus on seminal and recent research that establishes chromatin regulatory roles for both endogenous and microbial metabolites. We also highlight key physiologic and disease settings where microbial metabolite-host chromatin interactions have been established and/or may be pertinent.

Genomic Variants Associated with Resistance to High Fat Diet Induced Obesity in a Primate Model

Maternal obesity contributes to an increased risk of lifelong morbidity and mortality for both the mother and her offspring. In order to better understand the molecular mechanisms underlying these risks, we previously established and extensively characterized a primate model in Macaca fuscata (Japanese macaque). In prior studies we have demonstrated that a high fat, caloric dense maternal diet structures the offspring’s epigenome, metabolome, and intestinal microbiome. During the course of this work we have consistently observed that a 36% fat diet leads to obesity in the majority, but not all, of exposed dams. In the current study, we sought to identify the genomic loci rendering resistance to obesity despite chronic consumption of a high fat diet in macaque dams. Through extensive phenotyping together with exon capture array and targeted resequencing, we identified three novel single nucleotide polymorphisms (SNPs), two in apolipoprotein B (APOB) and one in phospholipase A2 (PLA2G4A) that significantly associated with persistent weight stability and insulin sensitivity in lean macaques. By application of explicit orthogonal modeling (NOIA), we estimated the polygenic and interactive nature of these loci against multiple metabolic traits and their measures (i.e., serum LDL levels) which collectively render an obesity resistant phenotype in our adult female dams.

Metabolic history impacts mammary tumor epithelial hierarchy and early drug response in mice

The emerging links between breast cancer and metabolic dysfunctions brought forth by the obesity pandemic predict a disproportionate early disease onset in successive generations. Moreover, sensitivity to chemotherapeutic agents may be influenced by the patient's metabolic status that affects the disease outcome. Maternal metabolic stress as a determinant of drug response in progeny is not well defined. Here, we evaluated mammary tumor response to doxorubicin in female mouse mammary tumor virus-Wnt1 transgenic offspring exposed to a metabolically compromised environment imposed by maternal high-fat diet. Control progeny were from dams consuming diets with regular fat content. Maternal high-fat diet exposure increased tumor incidence and reduced tumor latency but did not affect tumor volume response to doxorubicin, compared with control diet exposure. However, doxorubicin-treated tumors from high-fat-diet-exposed offspring demonstrated higher proliferation status (Ki-67), mammary stem cell-associated gene expression (Notch1, Aldh1) and basal stem cell-like (CD29(hi)CD24(+)) epithelial subpopulation frequencies, than tumors from control diet progeny. Notably, all epithelial subpopulations (CD29(hi)CD24(+), CD29(lo)CD24(+), CD29(hi)CD24(+)Thy1(+)) in tumors from high-fat-diet-exposed offspring were refractory to doxorubicin. Further, sera from high-fat-diet-exposed offspring promoted sphere formation of mouse mammary tumor epithelial cells and of human MCF7 cells. Untargeted metabolomics analyses identified higher levels of kynurenine and 2-hydroxyglutarate in plasma of high-fat diet than control diet offspring. Kynurenine/doxorubicin co-treatment of MCF7 cells enhanced the ability to form mammosphere and decreased apoptosis, relative to doxorubicin-only-treated cells. Maternal metabolic dysfunctions during pregnancy and lactation may be targeted to reduce breast cancer risk and improve early drug response in progeny, and may inform clinical management of disease.

Hepatic Mitochondrial Pyruvate Carrier 1 Is Required for Efficient Regulation of Gluconeogenesis and Whole-Body Glucose Homeostasis

Gluconeogenesis is critical for maintenance of euglycemia during fasting. Elevated gluconeogenesis during type 2 diabetes (T2D) contributes to chronic hyperglycemia. Pyruvate is a major gluconeogenic substrate and requires import into the mitochondrial matrix for channeling into gluconeogenesis. Here, we demonstrate that the mitochondrial pyruvate carrier (MPC) comprising the Mpc1 and Mpc2 proteins is required for efficient regulation of hepatic gluconeogenesis. Liver-specific deletion of Mpc1 abolished hepatic MPC activity and markedly decreased pyruvate-driven gluconeogenesis and TCA cycle flux. Loss of MPC activity induced adaptive utilization of glutamine and increased urea cycle activity. Diet-induced obesity increased hepatic MPC expression and activity. Constitutive Mpc1 deletion attenuated the development of hyperglycemia induced by a high-fat diet. Acute, virally mediated Mpc1 deletion after diet-induced obesity decreased hyperglycemia and improved glucose tolerance. We conclude that the MPC is required for efficient regulation of gluconeogenesis and that the MPC contributes to the elevated gluconeogenesis and hyperglycemia in T2D.

Obesity and Gestational Diabetes Mellitus Pathways for Programming in Mouse, Monkey, and Man—Where Do We Go Next? The 2014 Norbert Freinkel Award Lecture

Obesity and gestational diabetes mellitus continue to increase worldwide and span the spectrum of age, race, ethnicity, and socioeconomic status. Alarmingly, 1 in 10 infants and toddlers is obese, and 1 in 5 youths is both obese and at risk for metabolic syndrome prior to puberty. The mechanisms underlying how poor maternal health imparts risk for future metabolic disease in the offspring are beginning to emerge in deeply phenotyped human and nonhuman primate models. Maternal diet and obesity impact fuels, hormones, and inflammation with powerful effects on fetal metabolic systems. These are accompanied by persistent changes in the infant microbiome and epigenome and in offspring behavior. These results suggest that gestational and lactational dietary exposures are driving health risks in the next generation. Whether maternal diet can prevent changes in the womb to alter infant life-course disease risk is still unknown. Controlled, mechanistic studies to identify interventions are sorely needed for a healthier next generation.

Heritable IUGR and adult metabolic syndrome are reversible and associated with alterations in the metabolome following dietary supplementation of 1-carbon intermediates

Metabolic syndrome (MetS), following intrauterine growth restriction (IUGR), is epigenetically heritable. Recently, we abrogated the F2 adult phenotype with essential nutrient supplementation (ENS) of intermediates along the 1-carbon pathway. With the use of the same grandparental uterine artery ligation model, we profiled the F2 serum metabolome at weaning [postnatal day (d)21; n = 76] and adulthood (d160; n = 12) to test if MetS is preceded by alterations in the metabolome. Indicative of developmentally programmed MetS, adult F2, formerly IUGR rats, were obese (621 vs. 461 g; P < 0.0001), dyslipidemic (133 vs. 67 mg/dl; P < 0.001), and glucose intolerant (26 vs. 15 mg/kg/min; P < 0.01). Unbiased gas chromatography-mass spectrometry (GC-MS) profiling revealed 34 peaks corresponding to 12 nonredundant metabolites and 9 unknowns to be changing at weaning [false discovery rate (FDR) < 0.05]. Markers of later-in-life MetS included citric acid, glucosamine, myoinositol, and proline (P < 0.03). Hierarchical clustering revealed grouping by IUGR lineage and supplementation at d21 and d160. Weanlings grouped distinctly for ENS and IUGR by partial least-squares discriminate analysis (PLS-DA; P < 0.01), whereas paternal and maternal IUGR (IUGR(pat)/IUGR(mat), respectively) control-fed rats, destined for MetS, had a distinct metabolome at weaning (randomForest analysis; class error < 0.1) and adulthood (PLS-DA; P < 0.05). In sum, we have found that alterations in the metabolome accompany heritable IUGR, precede adult-onset MetS, and are partially amenable to dietary intervention.

Metabolomics in the developmental origins of obesity and its cardiometabolic consequences

In this review, we discuss the potential role of metabolomics to enhance understanding of obesity-related developmental origins of health and disease (DOHaD). We first provide an overview of common techniques and analytical approaches to help interested investigators dive into this relatively novel field. Next, we describe how metabolomics may capture exposures that are notoriously difficult to quantify, and help to further refine phenotypes associated with excess adiposity and related metabolic sequelae over the life course. Together, these data can ultimately help to elucidate mechanisms that underlie fetal metabolic programming. Finally, we review current gaps in knowledge and identify areas where the field of metabolomics is likely to provide insights into mechanisms linked to DOHaD in human populations.

Metabolomic profiles and childhood obesity

OBJECTIVE

To identify metabolite patterns associated with childhood obesity, to examine relations of these patterns with measures of adiposity and cardiometabolic risk, and to evaluate associations with maternal peripartum characteristics.

METHODS

Untargeted metabolomic profiling was used to quantify metabolites in plasma of 262 children (6-10 years). Principal components analysis was used to consolidate 345 metabolites into 18 factors and identified two that differed between obese (BMI ≥ 95‰; n = 84) and lean children (BMI < 85‰; n = 150). The relations of these factors with adiposity (fat mass, BMI, skinfold thicknesses) and cardiometabolic biomarkers (HOMA-IR, triglycerides, leptin, adiponectin, hsCRP, IL-6) using multivariable linear regression was then investigated. Finally, the associations of maternal prepregnancy obesity, gestational weight gain, and gestational glucose tolerance with the offspring metabolite patterns was examined.

RESULTS

A branched-chain amino acid (BCAA)-related pattern and an androgen hormone pattern were higher in obese vs. lean children. Both patterns were associated with adiposity and worse cardiometabolic profiles. For example, each increment in the BCAA and androgen pattern scores corresponded with 6% (95% CI: 1, 13%) higher HOMA-IR. Children of obese mothers had 0.61 (0.13, 1.08) higher BCAA score than their counterparts.

CONCLUSIONS

BCAA and androgen metabolites were associated with adiposity and cardiometabolic risk during mid-childhood. Maternal obesity may contribute to altered offspring BCAA metabolism.

High-fat maternal diet during pregnancy persistently alters the offspring microbiome in a primate model

The intestinal microbiome is a unique ecosystem and an essential mediator of metabolism and obesity in mammals. However, studies investigating the impact of the diet on the establishment of the gut microbiome early in life are generally lacking, and most notably so in primate models. Here we report that a high-fat maternal or postnatal diet, but not obesity per se, structures the offspring’s intestinal microbiome in Macaca fuscata (Japanese macaque). The resultant microbial dysbiosis is only partially corrected by a low-fat, control diet after weaning. Unexpectedly, early exposure to a high-fat diet diminished the abundance of non-pathogenic Campylobacter in the juvenile gut, suggesting a potential role for dietary fat in shaping commensal microbial communities in primates. Our data challenge the concept of an obesity-causing gut microbiome, and rather provide evidence for a contribution of the maternal diet in establishing the microbiota, which in turn affects intestinal maintenance of metabolic health.

The stunting syndrome in developing countries

Linear growth failure is the most common form of undernutrition globally. With an estimated 165 million children below 5 years of age affected, stunting has been identified as a major public health priority, and there are ambitious targets to reduce the prevalence of stunting by 40% between 2010 and 2025. We view this condition as a 'stunting syndrome' in which multiple pathological changes marked by linear growth retardation in early life are associated with increased morbidity and mortality, reduced physical, neurodevelopmental and economic capacity and an elevated risk of metabolic disease into adulthood. Stunting is a cyclical process because women who were themselves stunted in childhood tend to have stunted offspring, creating an intergenerational cycle of poverty and reduced human capital that is difficult to break. In this review, the mechanisms underlying linear growth failure at different ages are described, the short-, medium- and long-term consequences of stunting are discussed, and the evidence for windows of opportunity during the life cycle to target interventions at the stunting syndrome are evaluated.

Maternal genetic variation accounts in part for the associations of maternal size during pregnancy with offspring cardiometabolic risk in adulthood

BACKGROUND

Maternal pre-pregnancy body-mass index (ppBMI) and gestational weight gain (GWG) are associated with cardiometabolic risk (CMR) traits in the offspring. The extent to which maternal genetic variation accounts for these associations is unknown.

METHODS/RESULTS

In 1249 mother-offspring pairs recruited from the Jerusalem Perinatal Study, we used archival data to characterize ppBMI and GWG and follow-up data from offspring to assess CMR, including body mass index (BMI), waist circumference, glucose, insulin, blood pressure, and lipid levels, at an average age of 32. Maternal genetic risk scores (GRS) were created using a subset of SNPs most predictive of ppBMI, GWG, and each CMR trait, selected among 1384 single-nucleotide polymorphisms (SNPs) characterizing variation in 170 candidate genes potentially related to fetal development and/or metabolic risk. We fit linear regression models to examine the associations of ppBMI and GWG with CMR traits with and without adjustment for GRS. Compared to unadjusted models, the coefficient for the association of a one-standard-deviation (SD) difference in GWG and offspring BMI decreased by 41% (95%CI -81%, -11%) from 0.847 to 0.503 and the coefficient for a 1SD difference in GWG and WC decreased by 63% (95%CI -318%, -11%) from 1.196 to 0.443. For other traits, there were no statistically significant changes in the coefficients for GWG with adjustment for GRS. None of the associations of ppBMI with CMR traits were significantly altered by adjustment for GRS.

CONCLUSIONS

Maternal genetic variation may account in part for associations of GWG with offspring BMI and WC in young adults.

Preconception maternal nutrition: a multi-site randomized controlled trial

BACKGROUND

Research directed to optimizing maternal nutrition commencing prior to conception remains very limited, despite suggestive evidence of its importance in addition to ensuring an optimal nutrition environment in the periconceptional period and throughout the first trimester of pregnancy.

METHODS/STUDY DESIGN

This is an individually randomized controlled trial of the impact on birth length (primary outcome) of the time at which a maternal nutrition intervention is commenced: Arm 1: ≥ 3 mo preconception vs. Arm 2: 12-14 wk gestation vs. Arm 3: none.192 (derived from 480) randomized mothers and living offspring in each arm in each of four research sites (Guatemala, India, Pakistan, Democratic Republic of the Congo). The intervention is a daily 20 g lipid-based (118 kcal) multi-micronutient (MMN) supplement. Women randomized to receive this intervention with body mass index (BMI) <20 or whose gestational weight gain is low will receive an additional 300 kcal/d as a balanced energy-protein supplement. Researchers will visit homes biweekly to deliver intervention and monitor compliance, pregnancy status and morbidity; ensure prenatal and delivery care; and promote breast feeding. The primary outcome is birth length. Secondary outcomes include: fetal length at 12 and 34 wk; incidence of low birth weight (LBW); neonatal/infant anthropometry 0-6 mo of age; infectious disease morbidity; maternal, fetal, newborn, and infant epigenetics; maternal and infant nutritional status; maternal and infant microbiome; gut inflammatory biomarkers and bioactive and nutritive compounds in breast milk. The primary analysis will compare birth Length-for-Age Z-score (LAZ) among trial arms (independently for each site, estimated effect size: 0.35). Additional statistical analyses will examine the secondary outcomes and a pooled analysis of data from all sites.

DISCUSSION

Positive results of this trial will support a paradigm shift in attention to nutrition of all females of child-bearing age.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01883193.

Intake of high saturated-fat diets disturbs steroidogenesis, lipid metabolism and development of obese-swine conceptuses from early-pregnancy stages

The current study indicates that life-long intake, from early-life, of an obesogenic diet with high saturated-fat (HSF) content induces dyslipidemia (high plasma concentrations of triglycerides in concurrence with low concentrations of HDL-cholesterol) in obese swine with leptin resistance (Iberian sows). In case of pregnancy, ovarian features (ovulatory efficiency and luteal steroidogenesis) of sows fed with HSF are not affected but embryo features are affected at so early stages like 28 days of pregnancy (first quarter), although embryo viability was still not affected. In this way, offspring from HSF sows showed a higher incidence of alterations in their developmental trajectory, mainly due to a higher incidence of growth retardation, in their steroidogenic activity and in their availability of triglycerides and cholesterol. In conclusion, the results obtained in the present study illustrate the deleterious effects of maternal dyslipidemia, induced by the intake of HSF diets, on the oestradiol secretion of the conceptuses at early-pregnancy stages and, thus, on their developmental and metabolic features. This article is part of a Special Issue entitled 'Pregnancy and steroids'.

Newborn length predicts early infant linear growth retardation and disproportionately high weight gain in a low-income population

BACKGROUND

Stunting is prevalent by the age of 6 months in the indigenous population of the Western Highlands of Guatemala.

AIM

The objective of this study was to determine the time course and predictors of linear growth failure and weight-for-age in early infancy.

STUDY DESIGN AND SUBJECTS

One hundred and forty eight term newborns had measurements of length and weight in their homes, repeated at 3 and 6 months. Maternal measurements were also obtained.

RESULTS

Mean ± SD length-for-age Z-score (LAZ) declined from newborn -1.0 ± 1.01 to -2.20 ± 1.05 and -2.26 ± 1.01 at 3 and 6 months respectively. Stunting rates for newborn, 3 and 6 months were 47%, 53% and 56% respectively. A multiple regression model (R(2) = 0.64) demonstrated that the major predictor of LAZ at 3 months was newborn LAZ with the other predictors being newborn weight-for-age Z-score (WAZ), gender and maternal education∗maternal age interaction. Because WAZ remained essentially constant and LAZ declined during the same period, weight-for-length Z-score (WLZ) increased from -0.44 to +1.28 from birth to 3 months. The more severe the linear growth failure, the greater WAZ was in proportion to the LAZ.

CONCLUSION

The primary conclusion is that impaired fetal linear growth is the major predictor of early infant linear growth failure indicating that prevention needs to start with maternal interventions.

Relation of food intake behaviors and obesity development in young common marmoset monkeys

OBJECTIVE

Increasing prevalence of childhood obesity and associated risks of adult type disease have led to worldwide concern. It remains unclear how genetic predisposition, environmental exposure to obesogenic food, and developmental programming interact to lead to overweight and obese children. The development of a nonhuman primate model of obesity, and particularly juvenile obesity, is an important step to elucidating the factors associated with obesity and evaluating intervention strategies.

DESIGN AND METHODS

Infant marmosets were followed from birth to 12 months of age. Feeding phenotypes were determined through the use of behavioral observation, solid food intake trials, and liquid feeding trials monitored via lickometer.

RESULTS

Marmosets found to be obese at 12 months of age (more than 14% body fat) start consuming solid food sooner and initiate more time off of care givers. These individuals developed stable feeding phenotypes that included being more efficient consumers during liquid intake trials, drinking more grams of diet per contact with the licksit.

CONCLUSIONS

The weaning process appears to be particularly important in the development of feeding phenotypes and the development of juvenile obesity for the marmosets, and thus this is the time that should be focused upon for intervention testing in both nonhuman primates and children.

Postweaning exposure to a high-fat diet is associated with alterations to the hepatic histone code in Japanese macaques

BACKGROUND

Expression of circadian gene, Npas2, is altered in fetal life with maternal high-fat (HF) diet exposure by virtue of alterations in the fetal histone code. We postulated that these disruptions would persist postnatally.

METHODS

Pregnant macaques were fed a control (CTR) or HF diet and delivered at term. When offspring were weaned, they were placed on either CTR or HF diet for a period of 5 mo to yield four exposure models (in utero diet/postweaning diet: CTR/CTR n = 5; CTR/HF n = 4; HF/CTR n = 4; and HF/HF n = 5). Liver specimens were obtained at necropsy at 1 y of age.

RESULTS

Hepatic trimethylation of lysine 4 of histone H3 is decreased (CTR/HF 0.87-fold, P = 0.038; HF/CTR 0.84-fold, P = 0.038), whereas hepatic methyltransferase activity increased by virtue of diet exposure (HF/HF 1.3-fold, P = 0.019). Using chromatin immunoprecipitation to determine Npas2 promoter occupancy, we found alterations of both repressive and permissive histone modifications specifically with postweaning HF diet exposure.

CONCLUSION

We found that altered Npas2 expression corresponds with a change in the histone code within the Npas2 promoter.

Racial and ethnic health disparities in reproductive medicine: an evidence-based overview

Racial and ethnic health disparities in reproductive medicine exist across the life span and are costly and burdensome to our healthcare system. Reduction and ultimate elimination of health disparities is a priority of the National Institutes of Health who requires reporting of race and ethnicity for all clinical research it supports. Given the increasing rates of admixture in our population, the definition and subsequent genetic significance of self-reported race and ethnicity used in health disparity research is not straightforward. Some groups have advocated using self-reported ancestry or carefully selected single-nucleotide polymorphisms, also known as ancestry informative markers, to sort individuals into populations. Despite the limitations in our current definitions of race and ethnicity in research, there are several clear examples of health inequalities in reproductive medicine extending from puberty and infertility to obstetric outcomes. We acknowledge that socioeconomic status, education, insurance status, and overall access to care likely contribute to the differences, but these factors do not fully explain the disparities. Epigenetics may provide the biologic link between these environmental factors and the transgenerational disparities that are observed. We propose an integrated view of health disparities across the life span and generations focusing on the metabolic aspects of fetal programming and the effects of environmental exposures. Interventions aimed at improving nutrition and minimizing adverse environmental exposures may act synergistically to reverse the effects of these epigenetic marks and improve the outcome of our future generations.

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.

Nutrition and reproduction: links to epigenetics and metabolic syndrome in offspring

PURPOSE OF REVIEW

Inappropriate exposure of gametes and/or products of conception to nutritional imbalance alters critical metabolic set points in the offspring and increases propensity to disease. This review will focus on recent findings highlighting clear links to epigenetic modifications in response to dietary manipulations as well as nutritional strategies with the potential to mitigate the effects of an otherwise poor nutritional environment.

RECENT FINDINGS

Maternal nutritional imbalance, either through global nutritional manipulation or deficiencies in select nutrients, predisposes the offspring to metabolic disease. Disease susceptibility is linked to global and/or specific modifications of the epigenome at key metabolic regulatory genes. Paternal nutritional imbalance also increases the likelihood of metabolic disease in offspring through similar epigenetic mechanisms. Finally, dietary intervention with select nutrients has been shown to ameliorate postnatal disease phenotypes in offspring, although the exact molecular mechanisms have not been elucidated.

SUMMARY

Select nutrients, such as amino acids and vitamins, not only serve as building blocks for growth but also mediate a myriad of physiological functions, including providing substrates for DNA synthesis. These nutrients hold great promise as intervention strategies to combat a suboptimal developmental environment.

Maternal diet: a modulator for epigenomic regulation during development in nonhuman primates and humans

The importance of diet in health and disease has been well characterized in the past decades. Although the earlier focus of diet research was in the context of undernutrition and the importance of adequate nutrient intake to prevent malnutrition, in the current era of epidemic obesity the focus of our efforts has evolved toward understanding the effects of excess caloric intake. The current surge in childhood obesity rates suggests a correlation of maternal metabolic syndrome and obesity with programming of the fetal epigenome for metabolic diseases later in life. Alterations of the fetal genome, epigenome and metabolome have been well documented in cases of maternal malnutrition, including both overnutrition and undernutrition. It is of great interest and importance to understand how these divergent maternal factors regulate/program the fetus for metabolic diseases, and we and others have observed that epigenetic modifications to the fetal and placental epigenome accompany these reprogramming events. The following review summarizes recent studies on the effects of maternal diet and obesity on fetal epigenetics contributing to adult diseases later in life by taking advantage of state-of-the-art genomic, epigenomic and metagenomic techniques in nonhuman primate model systems.

A maternal high-fat diet modulates fetal SIRT1 histone and protein deacetylase activity in nonhuman primates

In nonhuman primates, we previously demonstrated that a maternal high-fat diet (MHFD) induces fetal nonalcoholic fatty liver disease (NAFLD) and alters the fetal metabolome. These changes are accompanied by altered acetylation of histone H3 (H3K14ac). However, the mechanism behind this alteration in acetylation remains unknown. As SIRT1 is both a lysine deacetylase and a crucial sensor of cellular metabolism, we hypothesized that SIRT1 may be involved in fetal epigenomic alterations. Here we show that in utero exposure to a MHFD, but not maternal obesity per se, increases fetal H3K14ac with concomitant decreased SIRT1 expression and diminished in vitro protein and histone deacetylase activity. MHFD increased H3K14ac and DBC1-SIRT1 complex formation in fetal livers, both of which were abrogated with diet reversal despite persistent maternal obesity. Moreover, MHFD was associated with altered expression of known downstream effectors deregulated in NAFLD and modulated by SIRT1 (e.g., PPARΑ, PPARG, SREBF1, CYP7A1, FASN, and SCD). Finally, ex vivo purified SIRT1 retains deacetylase activity on an H3K14ac peptide substrate with preferential activity toward acetylated histone H3; mutagenesis of the catalytic domain of SIRT1 (H363Y) abrogates H3K14ac deacetylation. Our data implicate SIRT1 as a likely molecular mediator of the fetal epigenome and metabolome under MHFD conditions.

Nutrition, epigenetics, and metabolic syndrome

SIGNIFICANCE

Epidemiological and animal studies have demonstrated a close link between maternal nutrition and chronic metabolic disease in children and adults. Compelling experimental results also indicate that adverse effects of intrauterine growth restriction on offspring can be carried forward to subsequent generations through covalent modifications of DNA and core histones.

RECENT ADVANCES

DNA methylation is catalyzed by S-adenosylmethionine-dependent DNA methyltransferases. Methylation, demethylation, acetylation, and deacetylation of histone proteins are performed by histone methyltransferase, histone demethylase, histone acetyltransferase, and histone deacetyltransferase, respectively. Histone activities are also influenced by phosphorylation, ubiquitination, ADP-ribosylation, sumoylation, and glycosylation. Metabolism of amino acids (glycine, histidine, methionine, and serine) and vitamins (B6, B12, and folate) plays a key role in provision of methyl donors for DNA and protein methylation.

CRITICAL ISSUES

Disruption of epigenetic mechanisms can result in oxidative stress, obesity, insulin resistance, diabetes, and vascular dysfunction in animals and humans. Despite a recognized role for epigenetics in fetal programming of metabolic syndrome, research on therapies is still in its infancy. Possible interventions include: 1) inhibition of DNA methylation, histone deacetylation, and microRNA expression; 2) targeting epigenetically disturbed metabolic pathways; and 3) dietary supplementation with functional amino acids, vitamins, and phytochemicals.

FUTURE DIRECTIONS

Much work is needed with animal models to understand the basic mechanisms responsible for the roles of specific nutrients in fetal and neonatal programming. Such new knowledge is crucial to design effective therapeutic strategies for preventing and treating metabolic abnormalities in offspring born to mothers with a previous experience of malnutrition.

Obesity and the risk and detection of fetal malformations

The incidence of obesity in pregnancy has increased over the past 2 decades, with nearly 50% of U.S. women aged 15-49 years classified as overweight or obese. Obesity (independent of diabetes) among gravidae poses unique risks that extend toward the fetus, with several large population-based analyses demonstrating independent increased risks for fetal malformations including neural tube defects, cardiac anomalies, and orofacial clefts, as well as stillbirth and macrosomia. Unfortunately, several lines of evidence also suggest that the quality of the prenatal fetal anatomic survey and certain aspects of prenatal diagnostic screening programs are significantly limited. The net effect is that among obese gravidae, the increased risk of fetal anomalies is further offset by a concomitant diminished ability to sonographically detect such malformations in the prenatal interval. The purpose of this summary review is to systematically examine the evidence suggesting an increased risk of fetal malformations in obese gravidae, the contributing role of diabetes, and the limitations of prenatal diagnostic and sonographic screening among this at-risk population.

Maternal high-fat diet impacts endothelial function in nonhuman primate offspring

OBJECTIVE:

The link between maternal under-nutrition and cardiovascular disease (CVD) in the offspring later in life is well recognized, but the impact of maternal over-nutrition on the offspring's cardiovascular function and subsequent risk for CVD later in life remains unclear. Here, we investigated the impact of maternal exposure to a high-fat/calorie diet (HFD) during pregnancy and early postnatal period on endothelial function of the offspring in a nonhuman primate model.

METHODS:

Offspring, naturally born to either a control (CTR) diet (14% fat calories) or a HFD (36% fat calories) consumption dam, were breast-fed until weaning at about 8 months of age. After weaning, the offspring were either maintained on the same diet (CTR/CTR, HFD/HFD), or underwent a diet switch (CTR/HFD, HFD/CTR). Blood samples and arterial tissues were collected at necropsy when the animals were about 13 months of age.

RESULTS:

HFD/HFD juveniles displayed an increased plasma insulin level and glucose-stimulated insulin secretion in comparison with CTR/CTR. In abdominal aorta, but not the renal artery, acetylcholine-induced vasorelaxation was decreased remarkably for HFD/HFD juveniles compared with CTR/CTR. HFD/HFD animals also showed a thicker intima wall and an abnormal vascular-morphology, concurrent with elevated expression levels of several markers related to vascular inflammation and fibrinolytic function. Diet-switching animals (HFD/CTR and CTR/HFD) displayed modest damage on the abdominal vessel.

CONCLUSION:

Our data indicate that maternal HFD exposure impairs offspring's endothelial function. Both early programming events and postweaning diet contribute to the abnormalities that could be reversed partially by diet intervention.

Maternal high fat diet is associated with decreased plasma n-3 fatty acids and fetal hepatic apoptosis in nonhuman primates

To begin to understand the contributions of maternal obesity and over-nutrition to human development and the early origins of obesity, we utilized a non-human primate model to investigate the effects of maternal high-fat feeding and obesity on breast milk, maternal and fetal plasma fatty acid composition and fetal hepatic development. While the high-fat diet (HFD) contained equivalent levels of n-3 fatty acids (FA's) and higher levels of n-6 FA's than the control diet (CTR), we found significant decreases in docosahexaenoic acid (DHA) and total n-3 FA's in HFD maternal and fetal plasma. Furthermore, the HFD fetal plasma n-6∶n-3 ratio was elevated and was significantly correlated to the maternal plasma n-6∶n-3 ratio and maternal hyperinsulinemia. Hepatic apoptosis was also increased in the HFD fetal liver. Switching HFD females to a CTR diet during a subsequent pregnancy normalized fetal DHA, n-3 FA's and fetal hepatic apoptosis to CTR levels. Breast milk from HFD dams contained lower levels of eicosopentanoic acid (EPA) and DHA and lower levels of total protein than CTR breast milk. This study links chronic maternal consumption of a HFD with fetal hepatic apoptosis and suggests that a potentially pathological maternal fatty acid milieu is replicated in the developing fetal circulation in the nonhuman primate.

Epigenomics: maternal high-fat diet exposure in utero disrupts peripheral circadian gene expression in nonhuman primates

The effect of in utero exposure to a maternal high-fat diet on the peripheral circadian system of the fetus is unknown. Using mRNA copy number analysis, we report that the components of the peripheral circadian machinery are transcribed in the nonhuman primate fetal liver in an intact phase-antiphase fashion and that Npas2, a paralog of the Clock transcription factor, serves as the rate-limiting transcript by virtue of its relative low abundance (10- to 1000-fold lower). We show that exposure to a maternal high-fat diet in utero significantly alters the expression of fetal hepatic Npas2 (up to 7.1-fold, P<0.001) compared with that in control diet-exposed animals and is reversible in fetal offspring from obese dams reversed to a control diet (1.3-fold, P>0.05). Although the Npas2 promoter remains largely unmethylated, differential Npas2 promoter occupancy of acetylation of fetal histone H3 at lysine 14 (H3K14ac) occurs in response to maternal high-fat diet exposure compared with control diet-exposed animals. Furthermore, we find that disruption of Npas2 is consistent with high-fat diet exposure in juvenile animals, regardless of in utero diet exposure. In summary, the data suggest that peripheral Npas2 expression is uniquely vulnerable to diet exposure.