Maternal obesity is thought to increase the offspring's risk of juvenile obesity and metabolic diseases; however, the mechanism(s) whereby excess maternal nutrition affects fetal development remain poorly understood. Here, we investigated in nonhuman primates the effect of chronic high-fat diet (HFD) on the development of fetal metabolic systems. We found that fetal offspring from both lean and obese mothers chronically consuming a HFD had a 3-fold increase in liver triglycerides (TGs). In addition, fetal offspring from HFD-fed mothers (O-HFD) showed increased evidence of hepatic oxidative stress early in the third trimester, consistent with the development of nonalcoholic fatty liver disease (NAFLD). O-HFD animals also exhibited elevated hepatic expression of gluconeogenic enzymes and transcription factors. Furthermore, fetal glycerol levels were 2-fold higher in O-HFD animals than in control fetal offspring and correlated with maternal levels. The increased fetal hepatic TG levels persisted at P180, concurrent with a 2-fold increase in percent body fat. Importantly, reversing the maternal HFD to a low-fat diet during a subsequent pregnancy improved fetal hepatic TG levels and partially normalized gluconeogenic enzyme expression, without changing maternal body weight. These results suggest that a developing fetus is highly vulnerable to excess lipids, independent of maternal diabetes and/or obesity, and that exposure to this may increase the risk of pediatric NAFLD.

Chromatin structure is epigenetically altered via covalent modifications of histones to allow for heritable gene regulation without altering the nucleotide sequence. Multiple lines of evidence from rodents have established a role for epigenetic remodeling in regulating gene transcription in response to an altered gestational milieu. However, to date, it is unknown whether variations in the intrauterine environment in primates similarly induce changes in key determinants of hepatic chromatin structure. We hypothesized that a maternal high-fat diet would alter the epigenomic profile of the developing offspring, which would result in alterations in fetal gene expression. Age-and weight-matched adult female Japanese macaques were placed on control (13% fat) or high-fat (35% fat) breeder diets and mated annually over a 4-year interval. Fetuses in successive years were delivered near term (e130 of 167 days) and underwent necropsy with tissue harvest. Fetal histones were acid extracted for characterization of H3 modification and chromatin immunoprecipitation (ChIP) with differential display PCR; fetal RNA, DNA, and cytoplasmic and nuclear protein extracts were similarly extracted for comparison. Chronic consumption of a maternal high-fat diet results in a threefold increase in fetal liver triglycerides and histologic correlates of non-alcoholic fatty liver disease. These gross changes in the fetal liver are accompanied by a statistically significant hyperacetylation of fetal hepatic tissue at H3K14 (199 . 85G9 . 64 . 096). However, epigenetic modifications on fetal hepatic H3 associated with gene repression were absent or subtle (PO0 . 05). Subsequent characterization of key epigenetic determinants associated with H3 acetylation marks revealed similar significant alterations in association with a high-fat maternal diet (e.g., relative fetal histone deacetylase 1 (HDAC1) gene expression 0 . 61G0 . 25; PZ0 . 011). Consistent with our mRNA expression profile, fetal nuclear extracts from offspring of highfat diet animals were observed to be significantly relatively deplete of HDAC1 protein (36 . 07G6 . 73 vs 83 . 18G7 . 51; PZ0 . 006) and in vitro HDAC functional activity (0 . 252G0 . 03 vs 0 . 698G0 . 02; P!0 . 001). We employ these observations in ChIP differential display PCR to attempt to identify potential fetal genes whose expression is reprogramed under conditions of a high-fat maternal diet. We quantitatively confirm a minimum of a 40% alteration in the expression of several genes of interest: glutamic pyruvate transaminase (alanine aminotransferase) 2 (GPT2) (1 . 59G0 . 23-fold; PZ0 . 08), DNAJA2 (1 . 36G0 . 21; PZ0 . 09), and Rdh12 (1 . 88G0 . 15; PZ0 . 01) are appreciably increased in fetal hepatic tissue from maternal caloric-dense diet animals when compared with control while Npas2, a peripheral circadian regulator, was significantly downmodulated in the offspring of high-fat diet animals (0 . 66G0 . 08; PZ0 . 03). In this study, we show that a current significant in utero exposure (caloric-dense hi...

We investigated the impact of poor maternal nutrition and metabolic health on the development of islets of the nonhuman primate (NHP). Interestingly, fetal offspring of high fat diet (HFD) fed animals had normal total islet and β cell mass; however, there was a significant reduction in α cell mass, and decreased expression of transcription factors involved in α cell differentiation. In juvenile animals all offspring maintained on a HFD during the postweaning period demonstrated increases in total islet mass, however, the control offspring displaying increased islet number, and HFD offspring displayed increased islet size. Finally, while control offspring had increases in α and β cells, the HFD offspring had increases only in β cell number. These studies indicate that consumption of a HFD diet during pregnancy in the NHP, independent of maternal metabolic health, causes long-term abnormalities in α cell plasticity that may contribute to chronic disease susceptibility.

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PurposeThe dramatic increase in childhood obesity greatly increases the risk of obesity and related health risks in adulthood. While this increase has been predominantly attributed to changes in nutrition and physical exercise in children, maternal health and diet during pregnancy are proving to be critical contributors as well. Concurrent with higher-fat diets in children, an increase in pediatric nonalcoholic fatty liver disease (NAFLD) has been shown. The purpose of these studies was to develop a non-human primate (NHP) model to investigate the contribution of chronic maternal high-fat diet on fetal metabolic systems and, in particular, the liver.MethodsJapanese macaques were placed on one of two diets; (1) control diet (CTR) - 13% of calories from fat and (2) high-fat diet - 35% of calories from fat for 3 years. Fetuses from these moms were obtained at gestational day 130 (full term = 175 days) each year of the diet and tissues were collected during necropsy.ResultsThe high-fat diet induced moderate maternal hyperinsulinemia and hyperleptinemia that increased over the 3 years. In addition, the fetuses displayed increased circulating free fatty acids and shifts in gene expression in liver and skeletal muscle indicating attempted adaptation to this high-fat environment. Fetuses from mothers on the high fat diet for 2-3 years showed changes in gene expression that suggest oxidative stress and insulin resistance. Furthermore, histological analysis of the liver showed increased staining for markers of oxidative stress as well as steatosis.ConclusionFetuses exposed to a high-fat maternal environment can initially generate an adaptive response; however, if the maternal condition persists, the fetus can develop metabolic sequelae. This maternal phenotype (overweight and on a high-fat diet) represents a large proportion of pregnancies within the United States and may be one of the most common health risks facing developing fetuses. These data suggest that increased maternal high fat consumption may underlie some of the metabolic disorders in children including the increased occurrence of NAFLD.AcknowledgmentsNIH grants DK060685, DK060685S2, HD14643, HD18185, and RR00163.