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Pregnancy conditions like maternal pre-pregnancy obesity and gestational diabetes (GDM) have been linked with the development of placenta, a critical organ required for maternal-fetal interface during gestation, and can lead to adverse health outcomes in both mother and fetus. However, the molecular signatures associated with these conditions are not fully understood. Epigenetic clocks, which are based upon DNA methylation of age-related CpGs, are thought to better reflect biological age compared to chronological age and have been used in different tissues as potential biomarkers. In the present study, we hypothesized that altered placental epigenetic gestational aging is associated with pre-pregnancy obesity and GDM. We explored these relationships by leveraging data from three diverse cohorts in the Environmental influences on Child Health Outcomes (ECHO) program (overall N=830) . First, we investigated associations between maternal pre-pregnancy obesity and GDM and estimated placental epigenetic gestational age acceleration (eGAA) . Next, we examined associations between these two conditions and methylation of each CpG site within the robust placental clock (558 CpGs) . Significant associations were not observed between pre-pregnancy obesity and GDM and eGAA. Interestingly, pre-pregnancy obesity was associated with methylation levels at 28 placental clock CpGs (q Disclosure K.Huff: None. C.Marsit: None. S.Niemiec: None. H.Volk: None. T.M.O'shea: None. R.Fry: None. K.Roell: None. C.Bulka: None. K.E.Boyle: None. C.Breton: None. A.Burt: None. D.Dabelea: None. L.Kahn: None. M.R.Karagas: None. Funding National Institutes of Health (UH3OD023348)

An adverse intrauterine environment is associated with the future risk of obesity and type 2 diabetes. Changes in placental function may underpin the intrauterine origins of adult disease, but longitudinal studies linking placental function with childhood outcomes are rare. Here, we determined the abundance and phosphorylation of protein intermediates involved in insulin signaling, inflammation, cortisol metabolism, protein glycosylation, and mitochondrial biogenesis in placental villus samples from healthy mothers from the Healthy Start cohort. Using MANOVA, we tested the association between placental proteins and offspring adiposity (fat mass percentage) at birth (n = 109) and infancy (4–6 months, n = 104), and adiposity, skinfold thickness, triglycerides, and insulin in children (4–6 years, n = 66). Placental IGF-1 receptor protein was positively associated with serum triglycerides in children. GSK3β phosphorylation at serine 9, a readout of insulin and growth factor signaling, and the ratio of phosphorylated to total JNK2 were both positively associated with midthigh skinfold thickness in children. Moreover, peroxisome proliferator–activated receptor γ coactivator (PGC)-1α abundance was positively associated with insulin in children. In conclusion, placental insulin/IGF-1 signaling, PGC-1α, and inflammation pathways were positively associated with metabolic outcomes in 4- to 6-year-old children, identifying a novel link between placental function and long-term metabolic outcomes.

OBJECTIVE: Our hypothesis was that the activity of placental nutrient-sensing pathways is associated with adiposity and metabolic health in childhood. RESEARCH DESIGN AND METHODS: Using placental villus samples from healthy mothers from the Healthy Start Study, we measured the abundance and phosphorylation of key intermediates in the mTOR, insulin, AMPK, and ER stress signaling pathways. Using multivariate multiple regression models, we tested the association between placental proteins and offspring adiposity (%fat mass) at birth (n = 109), 4–6 months (n = 104), and 4–6 years old (n = 64), adjusted for offspring sex and age. RESULTS: Placental mTORC1 phosphorylation was positively associated with adiposity at birth (R(2) = 0.13, P = 0.009) and 4–6 years (R(2) = 0.15, P = 0.046). The mTORC2 target PKCα was positively associated with systolic blood pressure at 4–6 years (β = 2.90, P = 0.005). AMPK phosphorylation was positively associated with adiposity at birth (β = 2.32, P = 0.023), but the ratio of phosphorylated to total AMPK was negatively associated with skinfold thickness (β = −2.37, P = 0.022) and body weight (β = −2.92, P = 0.005) at 4–6 years. CONCLUSIONS: This is the first report of associations between key placental protein activity measures and longitudinal child outcomes at various life stages. Our data indicate that AMPK and mTOR signaling are linked to cardiometabolic measures at birth and 4–6 years, providing novel insight into potential mechanisms underpinning how metabolic signaling in the placenta is associated with future risk of cardiovascular disease.

OBJECTIVE: Maternal obesity increases the risks for adverse pregnancy and offspring outcomes but with large heterogeneity. This study examined changes to the maternal metabolic milieu across pregnancy in women with obesity. It identified differences between a metabolically unhealthy obesity (MUO) phenotype and a metabolically healthy obesity (MHO) phenotype, as well as the differences in offspring adiposity between the two metabolic phenotypes. METHODS: In early pregnancy, women were classified with MHO (n = 13) or MUO (n = 9) based on the presence of zero or ≥2 risk factors for metabolic syndrome, respectively (systolic blood pressure > 130 mm Hg or diastolic blood pressure > 85 mm Hg, HDL cholesterol < 50 mg/dL, LDL cholesterol ≥ 100 mg/dL, triglycerides ≥ 150 mg/dL, and glucose ≥ 100 mg/dL). Area under the pregnancy concentration curve for glucose and triglycerides measured at early (13-16 weeks), mid- (24-27 weeks), and late (35-37 weeks) pregnancy, gestational weight gain (GWG), energy expenditure, maternal fat accretion, and infant body composition were compared. RESULTS: Maternal BMI, GWG, and fat accretion did not differ between MUO and MHO. Women with MUO had a greater area under the pregnancy concentration curve for glucose (+2,170 [382] mg/dL·day, p < 0.001) and triglycerides (+12,211 [3,916] mg/dL·day, p < 0.001). There were no differences in late-pregnancy total daily energy expenditure, but activity energy expenditure was significantly lower in MUO (−403 [144] kcal). MUO offspring had greater weight (+621 [205] g, p = 0.01) and adiposity (+5.8% [2.1%], p = 0.02) at 1 week of life but showed no differences in fat-free mass. CONCLUSIONS: Independent of GWG, MUO resulted in heightened exposure of fetal fat-promoting substrates. Differing metabolic phenotypes may explain heterogeneity of offspring adiposity born to women with obesity.

Exposure to maternal obesity may promote metabolic dysfunction in offspring. We used infant mesenchymal stem cells (MSCs) to experimentally examine cellular mechanisms of intergenerational health transmission. Our earlier reports show MSCs collected from infants of mothers with obesity had a dichotomous distribution in metabolic efficiency; they were either efficient (Ef-Ob) or inefficient (In-Ob) with respect to fatty acid oxidation (FAO). Here, we sought to determine if this was due to a primary defect in FAO. Accordingly, we measured FAO in myogenic differentiating MSCs under 3 conditions: (a) myogenesis alone, (b) excess fatty acid exposure, and (c) excess fatty acid exposure plus a chemical uncoupler to increase metabolic rate. Compared with normal weight and Ef-Ob MSCs, In-Ob displayed lower FAO in myogenesis alone and after fatty acid plus uncoupler, indicating In-Ob were less metabolically flexible after increasing lipid availability and metabolic rate, demonstrating a primary deficit in FAO. MSC FAO was negatively associated with fasting maternal glucose and insulin and positively associated with fasting HDL-cholesterol. MSC FAO was negatively associated with infant fat mass. These data indicate a less favorable maternal metabolic milieu, independent of maternal BMI, reduces intrinsic MSC FAO and is linked to higher infant adiposity as early as birth.

Introduction: Maternal obesity is associated with greater neonatal adiposity and increased offspring risk for type 2 diabetes (T2D) later in life. We have previously reported that mesenchymal stem cells (MSCs) isolated from umbilical cord tissue maintain similar metabolic phenotype to the infant, particularly when differentiated to adipocytes or myocytes. A well-established driver in the pathogenesis of T2D is skeletal muscle insulin resistance. Therefore, we hypothesized that MSCs from infants born to mothers with obesity would display insulin resistance when differentiated to myocytes. Objectives: The objective was to determine the effect of maternal obesity on offspring MSC insulin sensitivity (Si). Methods: MSCs were isolated from umbilical cord tissue from offspring born to either normal weight (BMI 21.1 ± 0.9, n = 9) or obese (BMI 32.9 ± 2.1, n = 10) mothers enrolled in the Healthy Start pre-birth cohort study in Colorado. Following differentiation into skeletal muscle myocytes, MSCs were serum starved and incubated with 14C-glucose, in the presence or absence of insulin. The rate of insulin-mediated 14C-glucose incorporation into glycogen, was used as an index of offspring Si. Results: Offspring Si did not correlate with maternal BMI (r = 0.26), nor was BMI different between groups when median-stratified by offspring Si. However, maternal free fatty acid levels positively correlated with offspring Si (r = 0.63, p < 0.05) and were significantly elevated in the high Si group (low Si vs. high Si; 332.1 ± 30.9 vs. 483.3 ± 48.7 uEq/L, p < 0.05). Conclusions: Offspring Si was not related to the BMI of the mother. Moreover, offspring Si was higher in cells from infants born to mothers with higher free fatty acids during pregnancy. Considering the role of insulin in somatic growth pathways, this phenomenon may serve to increase available nutrient storage capacity during early development. Disclosure A.B. Chaves: None. J.A. Johnson: None. D. Zheng: None. D. Dabelea: None. J.A. Houmard: None. K.E. Boyle: None. Funding American Heart Association (14PRE18230008); Nutrition Obesity Research Center (P30DK048520); National Institutes of Health (R01DK076648); Colorado National Center for Advancing Translational Sciences (UL1TR001082)

Overweight and obesity accompanies up to 70% of pregnancies and is a strong risk factor for offspring metabolic disease. Maternal obesity-associated inflammation and lipid profile are hypothesized as important contributors to excess offspring liver and skeletal muscle lipid deposition and oxidative stress. Here, we tested whether dams expressing the fat-1 transgene, which endogenously converts omega-6 (n-6) to omega-3 (n-3) polyunsaturated fatty acid, could protect wild-type (WT) offspring against high-fat diet induced weight gain, oxidative stress, and disrupted mitochondrial fatty acid oxidation. Despite similar body mass at weaning, offspring from fat-1 high-fat-fed dams gained less weight compared with offspring from WT high-fat-fed dams. In particular, WT males from fat-1 high-fat-fed dams were protected from post-weaning high-fat diet induced weight gain, reduced fatty acid oxidation, or excess oxidative stress compared with offspring of WT high-fat-fed dams. Adult offspring of WT high-fat-fed dams exhibited greater skeletal muscle triglycerides and reduced skeletal muscle antioxidant defense and redox balance compared with offspring of WT dams on control diet. Fat-1 offspring were protected from the reduced fatty acid oxidation and excess oxidative stress observed in offspring of WT high-fat-fed dams. These results indicate that a maternal fat-1 transgene has protective effects against offspring liver and skeletal muscle lipotoxicity resulting from a maternal high-fat diet, particularly in males. Altering maternal fatty acid composition, without changing maternal dietary composition or weight gain with high-fat feeding, may highlight important strategies for n-3-based prevention of developmental programming of obesity and its complications.

We have reported that umbilical cord mesenchymal stem cells (MSCs) from infants born to mothers with obesity have less AMP-activated protein kinase [AMPK] and less inhibitory phosphorylation of glycogen synthase kinase 3 [GSK3]β, a regulator of MSC differentiation. This is accompanied by a greater capacity for in vitro adipogenesis, which positively correlates with infant adiposity. Here we hypothesized that, independent of maternal pre-pregnancy (pp)BMI, maternal glucose and insulin would be associated with GSK3β and AMPK in undifferentiated infant MSCs. We studied 67 women (ppBMI 18-42 kg/m2) at mid (15-23 weeks) and late (24-32 weeks) gestation without preeclampsia or gestational diabetes, as well as their infants’ MSCs. We ran linear models to test the effect of fasting maternal glucose and insulin on each phosphorylated MSC protein, with infant sex and gestational age as covariates, ± ppBMI as a covariate to account for collinearity with metabolic measures. Linear model p-values and Pearson correlations are reported. Maternal glucose at mid (p = 0.03, r = 0.26) and late (p = 0.009, r = 0.35) gestation had a significant effect on AMPKThr172, with no effect of ppBMI, indicating greater AMPK activity with higher maternal glucose. Mid gestation insulin (p = 0.04, r = -0.21) was associated with GSK3βSer9, with the same trend for HOMA-IR—but not when ppBMI was included as a covariate, as it was also negatively associated with GSK3βSer9 (p = 0.02, r = -0.24), showing collinearity of ppBMI and insulin (r = 0.40). This signifies higher ppBMI and insulin with less GSK3β inhibition, which we have previously linked to greater adipogenesis. These results demonstrate the novel finding that maternal glucose during pregnancy is associated with perturbations to lipid metabolism pathways in infant MSCs across a wide range of ppBMI, giving important clues as to how maternal metabolism may impact infant metabolic disease risk. Disclosure M. Keleher: None. D. Dabelea: None. J.E. Friedman: Consultant; Self; Janssen Research & Development. K.E. Boyle: None. Funding National Institutes of Health (4UH3OD023248-03)

This study was designed to investigate mechanisms of lipid metabolic inflexibility in human obesity and the ability of fenofibrate (FENO) to increase skeletal muscle fatty acid oxidation (FAO) in primary human skeletal muscle cell cultures (HSkMC) exhibiting metabolic inflexibility. HSkMC from 10 lean and 10 obese, insulin resistant subjects were treated with excess fatty acid for 24 hours (24hFA) to gauge lipid-related metabolic flexibility. Metabolically inflexible HSkMC from obese individuals were then treated with 24hFA in combination with FENO to determine effectiveness for increasing FAO. Mitochondrial enzyme activity and FAO were measured in skeletal muscle from subjects with pre-diabetes (n=11) before and after 10 weeks of fenofibrate in vivo. 24hFA increased FAO to a greater extent in HSkMC from lean vs. obese subjects (+49% vs. +9%, for lean vs. obese, respectively; p

Severe demyelinating disorders of the central nervous system (CNS) such as multiple sclerosis (MS), can be devastating for many young lives. To date, the factors resulting in poor remyelination and repair are not well understood, and reparative therapies that benefit MS patients have yet to be developed. We have previously shown that the activity and abundance of Lipoprotein Lipase (LPL)-the rate-limiting enzyme in the hydrolysis of triglyceride-rich lipoproteins-is increased in Schwann cells and macrophages following nerve crush injury in the peripheral nervous system (PNS), suggesting that LPL may help scavenge myelin-derived lipids. We hypothesized that LPL may play a similar role in the CNS. To test this, mice were immunized with MOG35-55 peptide to induce experimental allergic encephalomyelitis (EAE). LPL activity was increased (p < 0.05) in the brain at 30 days post-injection, coinciding with partial remission of clinical symptoms. Furthermore, LPL abundance and activity was up-regulated (p < 0.05) at the transition between de-and re-myelination in lysolecithin-treated ex vivo cerebellar slices. Since microglia are the key immune effector cells of the CNS we determined the role of LPL in microglia. Lipid uptake was decreased (p < 0.001) in LPL-deficient BV-2 microglial cells compared to WT. In addition, LPL-deficient cells showed dramatically reduced expression of anti-inflammatory markers, YM1 (22 fold, p < 0.001), and arginase 1 (Arg1; 265 fold, p < 0.001) and increased expression of pro-inflammatory markers, such as iNOS compared to WT cells (+53 fold, p < 0.001). This suggests that LPL is a feature of reparative microglia, further supported by the metabolic and inflammatory profile of LPL-deficient microglia. Taken together, our data strongly suggest that LPL expression is a novel feature of a microglial phenotype that supports remyelination and repair through the clearance of lipid debris. This mechanism may be exploited to develop future reparative therapies for MS and primary neurodegenerative disorders (Alzheimer's disease (AD) and Parkinson's disease). Refereed/Peer-reviewed

Objective Investigate the effects of obesity and high-fat diet (HFD) exposure on fatty acid oxidation and TCA cycle intermediates and amino acids in skeletal muscle to better characterize energy metabolism. Methods Plasma and skeletal muscle metabolomic profiles were measured from lean and obese males before and after a 5-day HFD in the 4 h postprandial condition. Results At both time points, plasma short-chain acylcarnitine species (SCAC) were higher in the obese subjects, while the amino acids glycine, histidine, methionine, and citrulline were lower in skeletal muscle of obese subjects. Skeletal muscle medium-chain acylcarnitines (MCAC) C6, C8, C10:2, C10:1, C10, and C12:1 increased in obese subjects, but decreased in lean subjects, from pre- to post-HFD. Plasma content of C10:1 was also decreased in the lean but increased in the obese subjects from pre- to post-HFD. CD36 increased from pre- to post-HFD in obese but not lean subjects. Conclusions Lower skeletal muscle amino acid content and accumulation of plasma SCAC in obese subjects could reflect increased anaplerosis for TCA cycle intermediates, while accumulation of MCAC suggests limitations in β-oxidation. These measures may be important markers of or contributors to dysregulated metabolism observed in skeletal muscle of obese humans.

Background The IL-1 family cytokine interleukin 37 (IL-37) has broad anti-inflammatory effects and functions as a natural suppressor of innate inflammation and acquired immunity (1). We have reported that administration of recombinant human IL-37 to wild type mice or expression in mice transgenic for human IL-37 suppress proinflammatory cytokines and curb excessive inflammation in various conditions including inflammatory arthritis (2). Besides these anti-inflammatory effects, IL-37 also induces complex effects on metabolism. In particular, IL-37 can directly activate AMP-activated protein kinase (AMPK), a central regulator of cellular energy homeostasis and exercise-regulated metabolism (3). Objectives In this study, we evaluate the effects of IL-37 treatment on exercise tolerance in mice with systemic inflammation induced by LPS injection. We further investigate the effects of IL-37 on exercise tolerance in healthy mice, with specific focus on the metabolic changes induced by IL-37 administration and possibly responsible for a reduction in the metabolic costs of inflammation. Results Exogenous administration of IL-37 to healthy mice, not subjected to an inflammatory challenge, also improved exercise performance by 82% compared to vehicle-treated mice (p=0.01). Treatment with 8 daily doses of IL-37 resulted in a further 326% increase in endurance running time compared to the performance level of mice receiving vehicle (p=0.001). These properties required the engagement of the IL-1 decoy receptor 8 (IL-1R8) and the activation of AMP-activated protein kinase (AMPK), since both inhibition of AMPK and IL-1R8 deficiency abrogated the positive effects of IL-37 on exercise performance. Mechanistically, treatment with IL-37 induced marked metabolic changes with higher levels of muscle AMPK, greater rates of oxygen consumption and increased oxidative phosphorylation. Metabolomic analyses of plasma and muscles of mice treated with IL-37 revealed an increase in AMP/ATP ratio, reduced levels of pro-inflammatory mediator succinate and oxidative stress-related metabolites as well as changes in amino acid and purine metabolism. Conclusions These effects of IL-37 to limit the metabolic costs of chronic inflammation and to foster exercise tolerance provide a rationale for therapeutic use of IL-37 in the treatment of inflammation-mediated fatigue. References Dinarello CA, et al. (2016) Suppression of innate inflammation and immunity by interleukin-37. Eur J Immunol. Cavalli G, et al. (2016) Treating experimental arthritis with the innate immune inhibitor interleukin-37 reduces joint and systemic inflammation. Rheumatology (Oxford). Ballak DB, et al. (2014) IL-37 protects against obesity-induced inflammation and insulin resistance. Nature communications. Disclosure of Interest None declared

Maternal obesity is a global health problem that increases offspring obesity risk. The metabolic pathways underlying early developmental programming in human infants at risk for obesity remain poorly understood, largely due to barriers in fetal/infant tissue sampling. Utilizing umbilical cord-derived mesenchymal stem cells (uMSC) from offspring of normal weight and obese mothers, we tested whether energy metabolism and gene expression differ in differentiating uMSC myocytes and adipocytes, in relation to maternal obesity exposures and/or neonatal adiposity. Biomarkers of incomplete β-oxidation were uniquely positively correlated with infant adiposity and maternal lipid levels in uMSC myocytes from offspring of obese mothers only. Metabolic and biosynthetic processes were enriched in differential gene expression analysis related to maternal obesity. In uMSC adipocytes, maternal obesity and lipids were associated with downregulation in multiple insulin-dependent energy-sensing pathways including PI3K and AMPK. Maternal lipids correlated with uMSC adipocyte upregulation of the mitochondrial respiratory chain but downregulation of mitochondrial biogenesis. Overall, our data revealed cell-specific alterations in metabolism and gene expression that correlated with maternal obesity and adiposity of their offspring, suggesting tissue-specific metabolic and regulatory changes in these newborn cells. We provide important insight into potential developmental programming mechanisms of increased obesity risk in offspring of obese mothers.

Insulin resistance and systemic oxidative stress are prominent features of pregnancies complicated by maternal obesity or gestational diabetes mellitus (GDM). The role of skeletal muscle oxidative stress or mitochondrial capacity in obese pregnant women or obese women with GDM is unknown.We investigated whether obese pregnant women, compared with normal weight (NW) pregnant women, demonstrate decreased skeletal muscle mitochondrial enzyme activity and elevated markers of oxidative stress, and if these differences are more severe in obese women diagnosed with GDM.We measured mitochondrial enzyme activity and markers of oxidative stress in skeletal muscle tissue from NW pregnant women (n = 10), obese pregnant women with normal glucose tolerance (NGT; n = 10), and obese pregnant women with GDM (n = 8), undergoing cesarean delivery (∼37 wk gestation).Electron transport complex-II and manganese superoxide dismutase (MnSOD) enzyme activities were decreased in obese-NGT and obese-GDM, compared with NW women. The glutathione redox ratio (GSH:GSSG) was decreased in obese-NGT and obese-GDM, indicative of increased oxidative stress. Mitochondrial sirtuin (SIRT)3 mRNA content and enzyme activity were lower in skeletal muscle of obese-NGT and obese-GDM women. Importantly, acetylation of MnSOD, a SIRT3 target, was increased in obese-NGT and obese-GDM vs NW women and was inversely correlated with SIRT3 activity (r = -0.603), suggesting a mechanism for reduced MnSOD activity.These data show that obese pregnant women demonstrate decreased skeletal muscle mitochondrial respiratory chain enzyme activity and decreased mitochondrial antioxidant defense. Furthermore, reduced skeletal muscle SIRT3 activity may play a role in the increased oxidative stress associated with pregnancies complicated by obesity.

Contains fulltext : 169722.pdf (Publisher’s version ) (Closed access) IL-1 family member interleukin 37 (IL-37) has broad antiinflammatory properties and functions as a natural suppressor of innate inflammation. In this study, we demonstrate that treatment with recombinant human IL-37 reverses the decrease in exercise performance observed during systemic inflammation. This effect was associated with a decrease in the levels of plasma and muscle cytokines, comparable in extent to that obtained upon IL-1 receptor blockade. Exogenous administration of IL-37 to healthy mice, not subjected to an inflammatory challenge, also improved exercise performance by 82% compared with vehicle-treated mice (P = 0.01). Treatment with eight daily doses of IL-37 resulted in a further 326% increase in endurance running time compared with the performance level of mice receiving vehicle (P = 0.001). These properties required the engagement of the IL-1 decoy receptor 8 (IL-1R8) and the activation of AMP-activated protein kinase (AMPK), because both inhibition of AMPK and IL-1R8 deficiency abrogated the positive effects of IL-37 on exercise performance. Mechanistically, treatment with IL-37 induced marked metabolic changes with higher levels of muscle AMPK, greater rates of oxygen consumption, and increased oxidative phosphorylation. Metabolomic analyses of plasma and muscles of mice treated with IL-37 revealed an increase in AMP/ATP ratio, reduced levels of proinflammatory mediator succinate and oxidative stress-related metabolites, as well as changes in amino acid and purine metabolism. These effects of IL-37 to limit the metabolic costs of chronic inflammation and to foster exercise tolerance provide a rationale for therapeutic use of IL-37 in the treatment of inflammation-mediated fatigue.

The skeletal muscle of obese humans is characterized by an inability to appropriately respond to alterations in substrate availability. The purpose of this study was to determine if this metabolic inflexibility with obesity is retained in mitochondria of human skeletal muscle cells raised in culture (HSkMC) and to identify potential mechanisms involved. Mitochondrial respiration was measured in permeabilized myotubes cultured from lean and obese individuals before and after a 24-h lipid incubation. Mitochondrial respiration (state 3) in the presence of lipid substrate (palmitoyl carnitine) increased by almost twofold after lipid incubation in HSkMC from lean, but not obese subjects, indicative of metabolic inflexibility with obesity. The 24-h lipid incubation increased mitochondrial DNA (mtDNA) copy number in HSkMC from lean subjects by +16% (P

The most common maternal risk factor associated with neonatal complications during delivery is obesity. Although gestational diabetes mellitus (GDM) occurs in 5–10% of the pregnant population, obesity, by virtue of its prevalence, far outpaces GDM as the most important underlying risk factor for increased fetal adiposity. The mechanisms underlying maternal insulin resistance may play an important role in the diversion of excess fuels to the fetus. Maternal adipose depots increase in early pregnancy, followed by increased adipose tissue lipolysis and subsequent hyperlipidaemia, which mainly corresponds to increased triglyceride levels (TG). A positive correlation between maternal TG and infant body weight or fat mass has been found in both GDM and non-GDM obese women. Increased oxidative stress, altered adipokines, and inflammatory cytokines have also been found in obese pregnant women, suggesting an adverse metabolic outcome even in normoglycemic conditions.

High dietary fat intake leads to insulin resistance in skeletal muscle, and this represents a major risk factor for type 2 diabetes and cardiovascular disease. Mitochondrial dysfunction and oxidative stress have been implicated in the disease process, but the underlying mechanisms are still unknown. Here we show that in skeletal muscle of both rodents and humans, a diet high in fat increases the H(2)O(2)-emitting potential of mitochondria, shifts the cellular redox environment to a more oxidized state, and decreases the redox-buffering capacity in the absence of any change in mitochondrial respiratory function. Furthermore, we show that attenuating mitochondrial H(2)O(2) emission, either by treating rats with a mitochondrial-targeted antioxidant or by genetically engineering the overexpression of catalase in mitochondria of muscle in mice, completely preserves insulin sensitivity despite a high-fat diet. These findings place the etiology of insulin resistance in the context of mitochondrial bioenergetics by demonstrating that mitochondrial H(2)O(2) emission serves as both a gauge of energy balance and a regulator of cellular redox environment, linking intracellular metabolic balance to the control of insulin sensitivity.

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

Maternal obesity increases the risk for pediatric obesity; however, the molecular mechanisms in human infants remain poorly understood. We hypothesized that mesenchymal stem cells (MSCs) from infants born to obese mothers would demonstrate greater potential for adipogenesis and less potential for myogenesis, driven by differences in β-catenin, a regulator of MSC commitment. MSCs were cultured from the umbilical cords of infants born to normal-weight (prepregnancy [pp] BMI 21.1 ± 0.3 kg/m2; n = 15; NW-MSCs) and obese mothers (ppBMI 34.6 ± 1.0 kg/m2; n = 14; Ob-MSCs). Upon differentiation, Ob-MSCs exhibit evidence of greater adipogenesis (+30% Oil Red O stain [ORO], +50% peroxisome proliferator–activated receptor (PPAR)-γ protein; P < 0.05) compared with NW-MSCs. In undifferentiated cells, total β-catenin protein content was 10% lower and phosphorylated Thr41Ser45/total β-catenin was 25% higher (P < 0.05) in Ob-MSCs versus NW-MSCs (P < 0.05). Coupled with 25% lower inhibitory phosphorylation of GSK-3β in Ob-MSCs (P < 0.05), these data suggest greater β-catenin degradation in Ob-MSCs. Lithium chloride inhibition of GSK-3β increased nuclear β-catenin content and normalized nuclear PPAR-γ in Ob-MSCs. Last, ORO in adipogenic differentiating cells was positively correlated with the percent fat mass in infants (r = 0.475; P < 0.05). These results suggest that altered GSK-3β/β-catenin signaling in MSCs of infants exposed to maternal obesity may have important consequences for MSC lineage commitment, fetal fat accrual, and offspring obesity risk.

The rising prevalence of gestational diabetes mellitus (GDM) affects up to 18% of pregnant women with immediate and long-term metabolic consequences for both mother and infant. Abnormal glucose uptake and lipid oxidation are hallmark features of GDM prompting us to use an exploratory proteomics approach to investigate the cellular mechanisms underlying differences in skeletal muscle metabolism between obese pregnant women with GDM (OGDM) and obese pregnant women with normal glucose tolerance (ONGT). Functional validation was performed in a second cohort of obese OGDM and ONGT pregnant women. Quantitative proteomic analysis in rectus abdominus skeletal muscle tissue collected at delivery revealed reduced protein content of mitochondrial complex I (C-I) subunits (NDUFS3, NDUFV2) and altered content of proteins involved in calcium homeostasis/signaling (calcineurin A, α1-syntrophin, annexin A4) in OGDM (n = 6) vs. ONGT (n = 6). Follow-up analyses showed reduced enzymatic activity of mitochondrial complexes C-I, C-III, and C-IV (−60–75%) in the OGDM (n = 8) compared with ONGT (n = 10) subjects, though no differences were observed for mitochondrial complex protein content. Upstream regulators of mitochondrial biogenesis and oxidative phosphorylation were not different between groups. However, AMPK phosphorylation was dramatically reduced by 75% in the OGDM women. These data suggest that GDM is associated with reduced skeletal muscle oxidative phosphorylation and disordered calcium homeostasis. These relationships deserve further attention as they may represent novel risk factors for development of GDM and may have implications on the effectiveness of physical activity interventions on both treatment strategies for GDM and for prevention of type 2 diabetes postpartum.

Context: In lean individuals, increasing dietary lipid can elicit an increase in whole body lipid oxidation; however, with obesity the capacity to respond to changes in substrate availability appears to be compromised. Objective: To determine whether the responses of genes regulating lipid oxidation in skeletal muscle differed between lean and insulin resistant obese humans upon exposure to a high-fat diet (HFD). Design and Setting: A 5-d prospective study conducted in the research unit of an academic center. Participants: Healthy, lean (n = 12; body mass index = 22.1 ± 0.6 kg/m2), and obese (n=10; body mass index = 39.6 ± 1.7 kg/m2) males and females, between ages 18 and 30. Intervention: Participants were studied before and after a 5-d HFD (65% fat). Main Outcome Measures: Skeletal muscle biopsies (vastus lateralis) were obtained in the fasted and fed states before and after the HFD and mRNA content for genes involved with lipid oxidation determined. Skeletal muscle acylcarnitine content was determined in the fed states before and after the HFD. Results: Peroxisome proliferator activated receptor (PPAR) α mRNA content increased in lean, but not obese, subjects after a single high-fat meal. From Pre- to Post-HFD, mRNA content exhibited a body size × HFD interaction, where the lean individuals increased while the obese individuals decreased mRNA content for pyruvate dehydrogenase kinase 4, uncoupling protein 3, PPARα, and PPARγ coactivator-1α (P ≤ 0.05). In the obese subjects medium-chain acylcarnitine species tended to accumulate, whereas no change or a reduction was evident in the lean individuals. Conclusions: These findings indicate a differential response to a lipid stimulus in the skeletal muscle of lean and insulin resistant obese humans.

The purpose of this study was to determine if a high-fat diet would result in a higher lipolytic rate in subcutaneous adipose tissue than a lower-fat diet in sedentary nonlean men. Six participants (healthy males; 18-40 years old; body mass index, 25-37 kg/m 2 ) underwent 2 weeks on a high-fat or well-balanced diet of similar energy content (approximately 6695 kJ) in randomized order with a 10-day washout period between diets. Subcutaneous abdominal adipose tissue lipolysis was determined over the course of a day using microdialysis after both 2-week diet sessions. Average interstitial glycerol concentrations (index of lipolysis) as determined using microdialysis were higher after the high-fat diet (210.8 ± 27.9 μ mol/L) than after a well-balanced diet (175.6 ± 23.3 μ mol/L; P = .026). There was no difference in adipose tissue microvascular blood flow as determined using the microdialysis ethanol technique. These results demonstrate that healthy nonlean men who diet on the high-fat plan have a higher lipolytic rate in subcutaneous abdominal adipose tissue than when they diet on a well-balanced diet plan. This higher rate of lipolysis may result in a higher rate of fat mass loss on the high-fat diet; however, it remains to be determined if this higher lipolytic rate in men on the high-fat diet results in a more rapid net loss of triglyceride from the abdominal adipose depots, or if the higher lipolytic rate is counteracted by an increased rate of lipid storage.

Obesity is associated with a decrement in the ability of skeletal muscle to oxidize lipid. The purpose of this investigation was to determine whether clinical interventions (weight loss, exercise training) could reverse the impairment in fatty acid oxidation (FAO) evident in extremely obese individuals. FAO was assessed by incubating skeletal muscle homogenates with [1-14C]palmitate and measuring 14CO2 production. Weight loss was studied using both cross-sectional and longitudinal designs. Muscle FAO in extremely obese women who had lost weight (decrease in body mass of ∼50 kg) was compared with extremely obese and lean individuals (BMI of 22.8 ± 1.2, 50.7 ± 3.9, and 36.5 ± 3.5 kg/m2 for lean, obese, and obese after weight loss, respectively). There was no difference in muscle FAO between the extremely obese and weight loss groups, and FAO was depressed (−45%; P ≤ 0.05) compared with the lean subjects. Muscle FAO also did not change in extremely obese women ( n = 8) before and 1 yr after a 55-kg weight loss. In contrast, 10 consecutive days of exercise training increased ( P ≤ 0.05) FAO in the skeletal muscle of lean (+1.7-fold), obese (+1.8-fold), and previously extremely obese subjects after weight loss (+2.6-fold). mRNA content for PDK4, CPT I, and PGC-1α corresponded with FAO in that there were no changes with weight loss and an increase with physical activity. These data indicate that a defect in the ability to oxidize lipid in skeletal muscle is evident with obesity, which is corrected with exercise training but persists after weight loss.

Purpose Prostate cancer (PCa) is the second most common cause of cancer-related death among men in the United States. Due to the lipid-driven metabolic phenotype of PCa, imaging with 2-deoxy-2-[18F]fluoro-d-glucose ([18F]FDG) is suboptimal, since tumors tend to have low avidity for glucose. Procedures We have used the fat oxidation inhibitor etomoxir (2-[6-(4-chlorophenoxy)-hexyl]oxirane-2-carboxylate) that targets carnitine-palmitoyl-transferase-1 (CPT-1) to increase glucose uptake in PCa cell lines. Small hairpin RNA specific for CPT1A was used to confirm the glycolytic switch induced by etomoxir in vitro. Systemic etomoxir treatment was used to enhance [18F]FDG-positron emission tomography ([18F]FDG-PET) imaging in PCa xenograft mouse models in 24 h. Results PCa cells significantly oxidize more of circulating fatty acids than benign cells via CPT-1 enzyme, and blocking this lipid oxidation resulted in activation of the Warburg effect and enhanced [18F]FDG signal in PCa mouse models. Conclusions Inhibition of lipid oxidation plays a major role in elevating glucose metabolism of PCa cells, with potential for imaging enhancement that could also be extended to other cancers. Electronic supplementary material The online version of this article (doi:10.1007/s11307-014-0814-4) contains supplementary material, which is available to authorized users.