Effect of intrauterine growth retardation on liver and long-term metabolic risk

Dietary ferulic acid supplementation improves antioxidant capacity and lipid metabolism in liver of piglets with intrauterine growth retardation

Intrauterine growth retardation (IUGR) can result in early liver oxidative damage and abnormal lipid metabolism in neonatal piglets. Ferulic acid (FA), a phenolic compound widely found in plants, has many biological functions, such as anti-inflammation and anti-oxidation. Thus, we explored the effects of dietary FA supplementation on antioxidant capacity and lipid metabolism in newborn piglets with IUGR. In the study, 24 7-day-old piglets were divided into three groups: normal birth weight (NBW), IUGR, and IUGR + FA. The NBW and IUGR groups were fed formula milk as a basal diet, while the IUGR + FA group was fed a basal diet supplemented with 100 mg/kg FA. The trial lasted 21 days. The results showed that IUGR decreased absolute liver weight, increased transaminase activity, reduced antioxidant capacity, and disrupted lipid metabolism in piglets. Dietary FA supplementation enhanced absolute liver weight, reduced serum MDA level and ROS concentrations in serum and liver, markedly increased serum and liver GSH-PX and T-SOD activities, decreased serum HDL-C and LDL-C and liver NEFA, and increased TG content and HL activity in the liver. The mRNA expression related to the Nrf2-Keap1 signaling pathway and lipid metabolism in liver were affected by IUGR. Supplementing FA improved the antioxidant capacity of liver by down-regulating Keap1 and up-regulating the mRNA expression of SOD1 and CAT, and regulated lipid metabolism by increasing the mRNA expression level of Fasn, Pparα, LPL, and CD36. In conclusion, the study suggests that FA supplementation can improve antioxidant capacity and alleviate lipid metabolism disorders in IUGR piglets.

Intrauterine growth restriction in piglets modulates postnatal immune function and hepatic transcriptional responses independently of energy intake

Introduction: Insufficient prenatal nutrition can affect fetal development and lead to intrauterine growth restriction (IUGR). The aim of this study was to investigate hepatic transcriptional responses and innate immune function in piglets suffering from IUGR compared to normal-sized piglets at 3 days of age and explore whether the provision of an energy-rich supplement at birth could modulate these parameters. Methods: A total of 68 piglets were included in the study. Peripheral blood mononuclear cells were harvested for LPS stimulation, and organs were harvested post-mortem to quantify relative weights. Liver tissue was utilized for RNA sequencing coupled with gene-set enrichment analysis. Results: IUGR resulted in increased expression of genes such as PDK4 and substantial alterations in transcriptional pathways related to metabolic activity (e.g., citric acid and Krebs cycles), but these changes were equivalent in piglets given an energy-rich supplement or not. Transcriptomic analysis and serum biochemistry suggested altered glucose metabolism and a shift toward oxidation of fatty acids. IUGR piglets also exhibited suppression of genes related to innate immune function (e.g., CXCL12) and pathways related to cell proliferation (e.g., WNT and PDGF signaling). Moreover, they produced less IL-1β in response to LPS stimulation and had lower levels of blood eosinophils than normal-sized piglets. Discussion: Taken together, our results indicate that IUGR results in early-life alterations in metabolism and immunity that may not be easily restored by the provision of exogenous energy supplementation.

LRP6 Bidirectionally Regulates Insulin Sensitivity through Insulin Receptor and S6K Signaling in Rats with CG-IUGR

OBJECTIVE

Intrauterine growth restriction followed by postnatal catch-up growth (CG-IUGR) increases the risk of insulin resistance-related diseases. Low-density lipoprotein receptor-related protein 6 (LRP6) plays a substantial role in glucose metabolism. However, whether LRP6 is involved in the insulin resistance of CG-IUGR is unclear. This study aimed to explore the role of LRP6 in insulin signaling in response to CG-IUGR.

METHODS

The CG-IUGR rat model was established via a maternal gestational nutritional restriction followed by postnatal litter size reduction. The mRNA and protein expression of the components in the insulin pathway, LRP6/β-catenin and mammalian target of rapamycin (mTOR)/S6 kinase (S6K) signaling, was determined. Liver tissues were immunostained for the expression of LRP6 and β-catenin. LRP6 was overexpressed or silenced in primary hepatocytes to explore its role in insulin signaling.

RESULTS

Compared with the control rats, CG-IUGR rats showed higher homeostasis model assessment for insulin resistance (HOMA-IR) index and fasting insulin level, decreased insulin signaling, reduced mTOR/S6K/ insulin receptor substrate-1 (IRS-1) serine307 activity, and decreased LRP6/β-catenin in the liver tissue. The knockdown of LRP6 in hepatocytes from appropriate-for-gestational-age (AGA) rats led to reductions in insulin receptor (IR) signaling and mTOR/S6K/IRS-1 serine307 activity. In contrast, LRP6 overexpression in hepatocytes of CG-IUGR rats resulted in elevated IR signaling and mTOR/S6K/IRS-1 serine307 activity.

CONCLUSION

LRP6 regulated the insulin signaling in the CG-IUGR rats via two distinct pathways, IR and mTOR-S6K signaling. LRP6 may be a potential therapeutic target for insulin resistance in CG-IUGR individuals.

Effects of dietary epidermal growth factor supplementation on liver antioxidant capacity of piglets with intrauterine growth retardation

The present experiment was conducted to study the effects of dietary epidermal growth factor (EGF) supplementation on the liver antioxidant capacity of piglets with intrauterine growth retardation (IUGR). The present study consists of two experiments. In experiment 1, six normal-birth-weight (NBW) and six IUGR newborn piglets were slaughtered within 2 to 4 h after birth to compare the effects of IUGR on the liver antioxidant capacity of newborn piglets. The results showed that compared with NBW piglets, IUGR piglets had a lower birth weight and liver relative weight; IUGR piglets had a higher serum malondialdehyde (MDA) level, liver MDA level and hydrogen peroxide (H2O2) level, and had a lower liver total antioxidant capacity (T-AOC) level and glutathione peroxidase (GSH-Px) activity; IUGR trended to increase serum alanine aminotransferase activity, aspartate aminotransferase activity, and H2O2 level, and trended to decrease liver total superoxide dismutase activity. In experiment 2, six NBW piglets, and 12 IUGR piglets weaned at 21 d of age were randomly divided into the NC group (NBW piglets fed with basal diet); IC group (IUGR piglets fed with basal diet), and IE group (IUGR piglets fed with basal diet plus 2 mg/kg EGF), and feeding for 14 d. Organ index, serum parameters, liver antioxidant capacity, and liver antioxidant-related genes expression were measured. The results showed that compared to the IC group, dietary EGF supplementation (IE group) significantly reduced serum malondialdehyde level and H2O2 level, and liver protein carbonyl (PC) level and 8-hydroxydeoxyguanosine level of piglets with IUGR; dietary EGF supplementation (IE group) significantly increased serum T-AOC level, liver T-AOC level and GSH-Px activity; dietary supplemented with EGF (IE group) enhanced liver Nrf2, NQO1, HO1, and GPX1 mRNA expression compared to IC group. Pearson's correlation analysis further showed that EGF can alleviate liver oxidative injury caused by IUGR and improve the performance of IUGR piglets. In conclusion, EGF exhibited potent protective effects on IUGR-induced liver oxidative injury, by activating the Nrf2 signaling pathway to mediate the expression of downstream antioxidant enzymes and phase II detoxification enzymes (NQO1 and HO1), thereby alleviating liver oxidative damage and promoting the growth performance of IUGR piglets.

Altered Liver Metabolism, Mitochondrial Function, Oxidative Status, and Inflammatory Response in Intrauterine Growth Restriction Piglets with Different Growth Patterns before Weaning

Frequent occurrence of intrauterine growth restriction (IUGR) causes huge economic losses in the pig industry. Accelerated catch-up growth (CUG) in the early stage of life could restore multiple adverse outcomes of IUGR offspring; however, there is little knowledge about this beneficial phenomenon. We previously found that nutrient absorption related to intestinal function was globally promoted in CUG-IUGR piglets before weaning, which might be the dominant reason for CUG, but what this alteration could lead to in subsequent liver metabolism is still unknown. Firstly, a Normal, CUG, and non-catch-up growth (NCUG) piglet model before weaning was established by dividing eighty litters of newborn piglets into normal birth weight (NBW) and IUGR groups according to birth weight, and those piglets with IUGR but above-average weanling body weight were considered CUG, and the piglets with IUGR still below average body weight were considered NCUG at weaning day (d 26). Liver samples were collected and then systematically compared in glycolipid metabolism, mitochondrial function, antioxidant status, and inflammatory status among these three different growth models. Enhanced hepatic uptake of fatty acids, diminished de novo synthesis of fatty acids, and increased oxidation of fatty acids were observed in CUG livers compared to Normal and NCUG. In contrast, the NCUG liver showed enhanced glucose uptake and gluconeogenesis compared to Normal and CUG. We also observed deteriorating hepatic vacuolation in NCUG piglets, while increasing hepatic lipid deposition in CUG piglets. Besides, the expression of genes related to mitochondrial energy metabolism and biogenesis was reduced in CUG piglets and the phosphorylation level of AMPK was significantly higher compared to Normal (p < 0.05). Moreover, NCUG liver showed decreased T-AOC (p < 0.01) and GSH-PX (p < 0.05), increased MDA concentrations (p < 0.01), upregulated phosphorylation levels of ERK and NF-κB (p < 0.05), and elevated pro-inflammatory factors IL-1β, IL-6 and TNF-α (p < 0.05) compared to Normal. Furthermore, correlation analysis revealed a significant positive correlation between glucose metabolism and inflammatory factors, while a negative correlation between mitochondrial function-related genes and fatty acid transport. NGUG piglets showed simultaneous enhancement of glucose uptake and gluconeogenesis, as well as reduced antioxidant capacity and increased inflammatory status, whereas CUG comes at the expense of impaired hepatic mitochondrial function and pathological fat accumulation.

Effects of maternal branched-chain amino acid and alanine supplementation on growth and biomarkers of protein metabolism in dams fed a low-protein diet and their offspring

A considerable number of studies have reported that maternal protein restriction may disturb fetal growth and organ development due to a lower availability of amino acids. Leucine, one of branched-chain amino acid (BCAA) promotes protein synthesis through mechanistic target of rapamycin signaling. Here, we investigated the effects of BCAA supplementation in the dams fed a low-protein diet on serum and hepatic biochemical parameters of protein metabolism of dams and their offspring. Female ICR mice were fed a control (20% casein), a low-protein (10% casein), a low-protein with 2% BCAAs or a low-protein with 2% alanine diet for 2 weeks before mating and then throughout pregnancy and lactation. Alanine was used as an amino nitrogen control for the BCAA. Dams and their male offspring were sacrificed at postnatal day 21. There were no changes in body weight and fat mass in low-protein fed dams; however, BCAA supplementation significantly increased fat mass and serum leptin levels. Low-protein diet consumption reduced maternal protein synthesis based on biochemical analysis of serum albumin and hepatic protein levels and immunoblotting of S6 protein, which were increased by BCAA and alanine supplementation. Offspring from dams fed a low-protein diet exhibited lower body and organ weights. Body weight and hepatic protein levels of the offspring were increased by alanine supplementation. However, the decreased serum biochemical parameters, including glucose, triglyceride, total protein and albumin levels in the low-protein offspring group were not changed in response to BCAA or alanine supplementation. A reduced density of the hepatic vessel system in the offspring from dams fed a low-protein diet was restored in the offspring from dams fed either BCAA and alanine-supplemented diet. These results suggest that supplementation of amino nitrogen per se may be responsible for inducing hepatic protein synthesis in the dams fed a low-protein diet and alleviating the distorted growth and liver development of their offspring.

Polydatin Attenuates Intra-Uterine Growth Retardation-Induced Liver Injury and Mitochondrial Dysfunction in Weanling Piglets by Improving Energy Metabolism and Redox Balance

The present study investigated the potential of polydatin to protect against liver injury and the mitochondrial dysfunction of weanling piglets suffering from intra-uterine growth retardation (IUGR). Thirty-six normal birth weight weanling piglets and an equal number of IUGR littermates were given a basal diet with or without polydatin (250 mg/kg) from 21 to 35 d of age. Plasma and liver samples were collected to measure biochemistry parameters at 35 d of age. IUGR caused hepatic apoptosis, mitochondrial dysfunction, and oxidative damage, along with a lower efficiency of energy metabolism and inferior antioxidant ability. Polydatin decreased apoptotic rate, improved the features of mitochondrial damage, inhibited mitochondrial swelling and superoxide anion formation, and preserved mitochondrial membrane potential in the liver. Concurrently, polydatin promoted mitochondrial biogenesis, increased sirtuin 1 activity, and upregulated the expression levels of several genes related to mitochondrial function and fitness. Polydatin also facilitated mitochondrial oxidative metabolism with a beneficial outcome of increased energy production. Furthermore, polydatin mitigated the IUGR-induced reduction in manganese superoxide dismutase activity and prevented the excessive accumulation of oxidative damaging products in the liver. These findings indicate that polydatin confers protection against hepatic injury and mitochondrial dysfunction in the IUGR piglets by improving energy metabolism and redox balance.

Dietary rumen-protected L-arginine or N-carbamylglutamate attenuated fetal hepatic inflammation in undernourished ewes suffering from intrauterine growth restriction

This study aimed to explore whether dietary rumen-protected L-arginine (RP-Arg) or N-carbamylglutamate (NCG) supplementation to feed-restricted pregnant ewes counteracts fetal hepatic inflammation and innate immune dysfunction associated with intrauterine growth retardation (IUGR) in ovine fetuses. On d 35 of pregnancy, twin-bearing Hu ewes (n = 32) were randomly assigned to 4 treatment groups (8 ewes and 16 fetuses per group) and fed diets containing 100% of the NRC requirements (CON), 50% of the NRC requirements (RES), RES + RP-Arg (20 g/d) (RESA), or RES + NCG (5 g/d) (RESN). At 08:00 on d 110 of gestation, fetal blood and liver tissue samples were collected. The levels of triglyceride, free fatty acid, cholesterol and β-hydroxybutyrate in the fetal blood of RESA and RESN groups were lower (P < 0.05) than those of the RES group, but were higher (P < 0.05) than those of the CON group. The interleukin (IL)-6 and IL-1 levels in fetal blood and liver tissue as well as the myeloid differentiation primary response 88 (MyD88), transforming growth factor β (TGFβ), and nuclear factor kappa B (NF-κB) mRNA levels in the fetal liver were decreased (P < 0.05) by the NCG or RP-Arg supplementation compared to the RES treatment. Similarly, the toll-like receptor (TLR)-4, MyD88, TGFβ, and p-c-Jun N-terminal kinase (JNK) protein levels in the fetal liver were reduced (P < 0.05) in the NCG and RP-Arg -supplemented groups compared to the RES group. These results showed that dietary supplementation of RP-Arg or NCG to underfed pregnant ewes could protect against IUGR fetal hepatic inflammation via improving lipid metabolism, down-regulating the TLR-4 and the inflammatory JNK and NF-κB signaling pathways, and decreasing cytokine production in ovine fetal blood and liver tissue.

Fetal Cardiac Lipid Sensing Triggers an Early and Sex-related Metabolic Energy Switch in Intrauterine Growth Restriction

CONTEXT

Intrauterine growth restriction (IUGR) is an immediate outcome of an adverse womb environment, exposing newborns to developing cardiometabolic disorders later in life.

OBJECTIVE

This study investigates the cardiac metabolic consequences and underlying mechanism of energy expenditure in developing fetuses under conditions of IUGR.

METHODS

Using an animal model of IUGR characterized by uteroplacental vascular insufficiency, mitochondrial function, gene profiling, lipidomic analysis, and transcriptional assay were determined in fetal cardiac tissue and cardiomyocytes.

RESULTS

IUGR fetuses exhibited an upregulation of key genes associated with fatty acid breakdown and β-oxidation (Acadvl, Acadl, Acaa2), and mitochondrial carnitine shuttle (Cpt1a, Cpt2), instigating a metabolic gene reprogramming in the heart. Induction of Ech1, Acox1, Acox3, Acsl1, and Pex11a indicated a coordinated interplay with peroxisomal β-oxidation and biogenesis mainly observed in females, suggesting sexual dimorphism in peroxisomal activation. Concurring with the sex-related changes, mitochondrial respiration rates were stronger in IUGR female fetal cardiomyocytes, accounting for enhanced adenosine 5'-triphosphate production. Mitochondrial biogenesis was induced in fetal hearts with elevated expression of Ppargc1a transcript specifically in IUGR females. Lipidomic analysis identified the accumulation of arachidonic, eicosapentaenoic, and docosapentaenoic polyunsaturated long-chain fatty acids (LCFAs) in IUGR fetal hearts, which leads to nuclear receptor peroxisome proliferator-activated receptor α (PPARα) transcriptional activation in cardiomyocytes. Also, the enrichment of H3K27ac chromatin marks to PPARα-responsive metabolic genes in IUGR fetal hearts outlines an epigenetic control in the early metabolic energy switch.

CONCLUSION

This study describes a premature and sex-related remodeling of cardiac metabolism in response to an unfavorable intrauterine environment, with specific LCFAs that may serve as predictive effectors leading to IUGR.

Association between gestational cannabis exposure and maternal, perinatal, placental, and childhood outcomes

Globally, the availability and formulations for the administration of cannabis are changing with decriminalization or legalization of recreational use in some jurisdictions, and the prescription of cannabis also occurring. These changes are likely to affect the prevalence of use, including by women of childbearing age. The effects of in utero and infant alcohol and tobacco exposure are well-documented, but the outcomes of cannabis exposure are less certain. The content of delta-9-tetrahydrocannabinol (THC), the psychoactive component of cannabis has progressively increased over several decades. This review explores the limited knowledge surrounding the epidemiology of gestational and postnatal cannabis exposure and implications for the mother-placenta-fetus/neonate triad. We examine cannabis' effects from antenatal and lactation exposure on (a) pregnancy and perinatal outcomes, (b) placental health, and (c) longer term cardiometabolic and neurodevelopmental risks and outcomes. Though definitive outcomes are lacking, gestational cannabis has been associated with increased risk of other substance use during pregnancy; impaired placental blood flow; increased risk of small for gestational age births; and associated complications. Childhood and adolescent outcomes are sparsely assessed, with suggested outcomes including increased risk of depression and attention-deficit hyperactivity disorder. Cardiometabolic implications of gestational cannabis use may include maternal fatty liver, obesity, insulin resistance, and increased risk of gestational diabetes mellitus (GDM), with potential consequences for the fetus. Clinical implications for pediatric practice were explored in a bid to understand any potential risk or impact on child health and development.

Technique for comprehensive fetal hepatic blood flow assessment in sheep using 4D flow MRI

KEY POINTS

The comprehensive visualization and quantification of in vivo fetal hepatic haemodynamics, particularly the shunting of ductus venosus blood, has been elusive and is not yet fully understood. We introduce the combination of chronically instrumented fetal sheep and 4D flow MRI of the whole fetal liver, which allows retrospective blood flow measurement in all visible vessels as well as qualitative assessment. The applicability and usefulness of this technique is exhibited in normally grown fetal Merino sheep in mid- and late-gestation with detailed dynamic distribution of hepatic blood flow presented. The feasibility of this approach in clinical pathology is demonstrated in two growth-restricted fetuses at mid-gestation. Further exemplification of blood flow quantification is performed over major hepatic vessels.

ABSTRACT

Although the fetal vasculature has been demarcated and well understood for several decades, the corresponding haemodynamics permitting oxygen- and nutrient-rich blood delivery to the fetal organs has been comparatively difficult to study. We married two well-established methods: 4D flow MRI, a volumetric and dynamic blood-flow measurement technique, and chronically instrumented sheep to broadly assess fetal hepatic circulation. We performed this technique in mid- and late-gestation fetal Merino sheep under normoxemic conditions and major hepatic vasculature was segmented to quantify blood flow and related parameters. Dynamic blood flow was visualized, exhibiting an acceleration of umbilical vein blood through the ductus venosus as well as spiralling into the inferior vena cava where its stream remained separate from that of the hepatic veins and lower body. Ductus venosus changes from mid- to late-gestation included larger diameter (mid: 5.8 ± 0.9 vs. late: 7.1 ± 1.1 mm; P = 0.003) and cross-sectional area (mid: 27.1 ± 8.6 vs. late: 40.4 ± 11.8 mm2 ; P = 0.003), and lower velocity averaged over the cardiac cycle (mid: 15.7 ± 5.4 vs. late: 9.8 ± 7.0 cm s-1 ; P = 0.020). This resulted in higher magnitude blood flow (indexed to umbilical vein input) at mid-gestation in the ductus venosus (mid: 0.73 ± 0.21; late: 0.46 ± 0.21; P = 0.008). The visualization and quantification results support the further use of this technique to better understand regional blood flow changes during normal or abnormal fetal growth, as well as to observe acute haemodynamic responses to physiological challenges or drug interventions.

Growth retardation-responsive analysis of mRNAs and long noncoding RNAs in the liver tissue of Leiqiong cattle

As an important type of non-coding RNA molecule, long non-coding RNAs (lncRNAs) have varied roles in many biological processes, and have been studied extensively over the past few years. However, little is known about lncRNA-mediated regulation during cattle growth and development. Therefore, in the present study, RNA sequencing was used to determine the expression level of mRNAs and lncRNAs in the liver of adult Leiqiong cattle under the condition of growth retardation and normal growth. We totally detected 1,124 and 24 differentially expressed mRNAs and lncRNAs, respectively. The differentially expressed mRNAs were mainly associated with growth factor binding, protein K63-linked ubiquitination and cellular protein metabolic process; additionally, they were significantly enriched in the growth and development related pathways, including PPAR signaling pathway, vitamin B6 metabolism, glyoxylate and dicarboxylate metabolism. Combined analysis showed that the co-located differentially expressed lncRNA Lnc_002583 might positively influence the expression of the corresponding genes IFI44 and IFI44L, exerting co-regulative effects on Leiqiong cattle growth and development. Thus, we made the hypothesis that Lnc_002583, IFI44 and IFI44L might function synergistically to regulate the growth of Leiqiong cattle. This study provides a catalog of Leiqiong cattle liver mRNAs and lncRNAs, and will contribute to a better understanding of the molecular mechanism underlying growth regulataion.

Pterostilbene attenuates liver injury and oxidative stress in intrauterine growth-retarded weanling piglets

OBJECTIVES

The aim of the present study was to investigate the potential of pterostilbene, a beneficial component primarily found in blueberries, to alleviate the intrauterine growth retardation (IUGR)-induced early liver injury and oxidative stress in a porcine model.

METHODS

Thirty-six IUGR piglets and an equal number of normal birth weight (NBW) counterparts received a diet with or without pterostilbene (250 mg/kg diet) during the first week post-weaning. Parameters related to the hepatic injury, oxidative stress, and antioxidant defense mechanisms were analyzed.

RESULTS

Relative to NBW, IUGR induced liver injury, which corresponded to increments in circulating alanine transaminase activity and hepatic apoptotic cell rate, superoxide radical generation, and the accumulation of oxidative damage products (P < 0.05). Administering pterostilbene reduced plasma transaminase activities, decreased hepatocyte apoptosis rate, and prevented the augmented levels of hepatic superoxide anion, 8-hydroxy-2 deoxyguanosine, and 4-hydroxynonenal-modified protein (P < 0.05). In terms of the hepatic antioxidant function, pterostilbene was efficient in improving the superoxide dismutase activity and the metabolic cycle between reduced glutathione and its oxidized form (P < 0.05). The pterostilbene-supplemented diet facilitated the nuclear translocation of nuclear factor erythroid-2-related factor 2 (NRF2) and promoted the expression levels of superoxide dismutase 2 in the liver of IUGR piglets (P < 0.05).

CONCLUSION

This study indicates that pterostilbene treatment has an auxiliary therapeutic potential to ameliorate early liver injury in IUGR neonates, presumably by stimulating the NRF2 signals and the associated antioxidant function.

Epigenetics and In Utero Acquired Predisposition to Metabolic Disease

Epidemiological evidence has shown an association between prenatal malnutrition and a higher risk of developing metabolic disease in adult life. An inadequate intrauterine milieu affects both growth and development, leading to a permanent programming of endocrine and metabolic functions. Programming may be due to the epigenetic modification of genes implicated in the regulation of key metabolic mechanisms, including DNA methylation, histone modifications, and microRNAs (miRNAs). The expression of miRNAs in organs that play a key role in metabolism is influenced by in utero programming, as demonstrated by both experimental and human studies. miRNAs modulate multiple pathways such as insulin signaling, immune responses, adipokine function, lipid metabolism, and food intake. Liver is one of the main target organs of programming, undergoing structural, functional, and epigenetic changes following the exposure to a suboptimal intrauterine environment. The focus of this review is to provide an overview of the effects of exposure to an adverse in utero milieu on epigenome with a focus on the molecular mechanisms involved in liver programming.

In Utero Dexamethasone Exposure Exacerbates Hepatic Steatosis in Rats That Consume Fructose During Adulthood

Distinct environmental insults might interact with fructose consumption and contribute to the development of metabolic disorders. To address whether in utero glucocorticoid exposure and fructose intake modulate metabolic responses, adult female Wistar rats were exposed to dexamethasone (DEX) during pregnancy, and the offspring were administered fructose at a later time. Briefly, dams received DEX during the third period of pregnancy, while control dams remained untreated. Offspring born to control and DEX-treated mothers were defined as CTL-off and DEX-off, respectively, while untreated animals were designated CTL-off-CTL and DEX-off-CTL. CLT-off and DEX-off treated with 10% fructose in the drinking water for 8 weeks are referred to as CTL-off-FRU and DEX-off-FRU. We found that fructose promoted glucose intolerance and whole-body gluconeogenesis in both CTL-off-FRU and DEX-off-FRU animals. On the other hand, hepatic lipid accumulation was significantly stimulated in DEX-off-FRU rats when compared to the CTL-off-FRU group. The DEX-off-FRU group also displayed impaired very-low-density lipoprotein (VLDL) production and reduced hepatic expression of apoB, mttp, and sec22b. DEX-off-FRU has lower hepatic levels of autophagy markers. Taken together, our results support the unprecedented notion that in utero glucocorticoid exposure exacerbates hepatic steatosis caused by fructose consumption later in life.

Lipid Intake Enhances Muscle Growth But Does Not Influence Glucose Kinetics in 3-Week-Old Low-Birth-Weight Neonatal Pigs

BACKGROUND

Low-birth-weight (LBWT) neonates grow at a slower rate than their normal-birth-weight (NBWT) counterparts and may develop hypoglycemia postnatally.

OBJECTIVE

We investigated whether dietary lipid supplementation would enhance growth and improve glucose production in LBWT neonatal pigs.

METHODS

Twelve 3-d-old NBWT (1.606 kg) crossbred pigs were matched to 12 LBWT (1.260 kg) same-sex littermates. At 6 d of age, 6 pigs in each group were fed a low-energy (LE) or a high-energy (HE) isonitrogenous formula containing 5.2% and 7.3% fat, respectively. Body composition was assessed using dual-energy X-ray absorptiometry; plasma glucose and glycerol kinetics were assessed using stable isotope tracers. After killing, weights of skeletal muscles and visceral organs were measured. Data were analyzed by ANOVA for a 2 × 2 factorial design; temporal effects were investigated using repeated-measures analysis.

RESULTS

Lipid supplementation did not affect body weight of LBWT or NBWT pigs. However, liver and longissimus dorsi weights as a percentage of body weight were greater for pigs fed an HE diet than for those fed an LE diet (4.3% compared with 3.4% and 1.5% compared with 1.2%, respectively) but remained less for LBWT than for NBWT pigs (3.8% compared with 3.9% and 1.3% compared with 1.5%, respectively) (P < 0.05). In addition, hepatic fat content increased (7.9 compared with 2.6 g) in pigs fed the HE compared with those fed the LE formula (P < 0.05). Lipid supplementation did not influence plasma glucose concentration which remained lower in the LBWT than in the NBWT group (4.1 compared with 4.5 mmol/L) (P < 0.05).

CONCLUSIONS

Our data suggest that lipid supplementation modestly improved growth of skeletal muscle and the liver but did not affect glucose homeostasis in all groups, and glucose concentration remained lower in LBWT than in NBWT pigs. These data suggest that the previously reported hyperglycemic effect of lipid supplementation may depend on the route of administration or age of the neonatal pig.

Interplay between early-life malnutrition, epigenetic modulation of the immune function and liver diseases

Early-life nutrition plays a critical role in fetal growth and development. Food intake absence and excess are the two main types of energy malnutrition that predispose to the appearance of diseases in adulthood, according to the hypothesis of 'developmental origins of health and disease'. Epidemiological data have shown an association between early-life malnutrition and the metabolic syndrome in later life. Evidence has also demonstrated that nutrition during this period of life can affect the development of the immune system through epigenetic mechanisms. Thus, epigenetics has an essential role in the complex interplay between environmental factors and genetics. Altogether, this leads to the inflammatory response that is commonly seen in non-alcoholic fatty liver disease (NAFLD), the hepatic manifestation of the metabolic syndrome. In conjunction, DNA methylation, covalent modification of histones and the expression of non-coding RNA are the epigenetic phenomena that affect inflammatory processes in the context of NAFLD. Here, we highlight current understanding of the mechanisms underlying developmental programming of NAFLD linked to epigenetic modulation of the immune system and environmental factors, such as malnutrition.

Impact of uteroplacental insufficiency on ovarian follicular pool in the rat

BACKGROUND

A low oxygen supply to the fetus causes intrauterine growth restriction and can affect gonadal development of the offspring, having a potential impact on fertility. We investigated histology and gene expression in the postnatal rat ovary after fetal hypoxia induced by uterine artery ligation.

METHODS

Sprague-Dawley rats underwent uterine artery ligation at day 19 of gestation. Offspring were sacrificed at 5, 20 and 40 days post-partum. Follicles were counted and classified in hematoxylin-eosin stained sections. Gene expression of 90 genes was analyzed by TaqMan® Low Density Array.

RESULTS

A significantly lower number of total and primordial follicles was detected in 20 days post-partum intrauterine growth restricted animals. Follicle density was not different at 40 days post-partum, suggesting that compensatory mechanisms occurred during the pre-pubertal window. Uterine artery ligation modified the expression of 24 genes involved in different cellular functions, among which proliferation, apoptosis and metabolism.

CONCLUSION

Ovarian follicle pool was affected by fetal hypoxia in early life, but this effect did not persist in puberty. Genes involved in cellular processes were affected at all ages, potentially implying long-term genetic alterations. Further analyses are needed to elucidate later effects of fetal hypoxia on ovarian function and fertility.

Formula derived Maillard reaction products in post-weaning intrauterine growth-restricted piglets induce developmental programming of hepatic oxidative stress independently of microRNA-21 and microRNA-155

We recently reported augmentation of lipid peroxidation products in the liver of intrauterine growth-restricted (IUGR) piglets fed a high load of Maillard reaction products (MRPs) during suckling period. The underlying mechanisms of MRPs effects remain unknown. Here, we studied the long-term impact of MRPs exposure on liver oxidative status of IUGR juvenile pigs. Livers of 54-day-old pigs suckled with formula containing either a high (HHF, n=8) or a low (LHF: n=8) load of MRPs were analyzed for protein carbonylation levels , activities and messenger RNA (mRNA) expression of glutathione (GSH) and main antioxidant regulators of redox homeostasis [Superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) were measured. In addition, mRNA levels of miRNA-21 and miRNA-155 were measured. The liver of HHF group exhibited a high level of lipid peroxidation with significantly increased expression and activity of SOD. Further in liver of HHF group, CAT activity was decreased as compared with LHF group, though with comparable total protein carbonyl contents, GSH contents, and expression of GPx and microRNAs (miRNA-21 and miRNA-155). Our findings suggest that the potential mechanism of MRPs-mediated oxidative stress programming in liver of IUGR piglets may occur via impairment of antioxidant defenses.

Developmental Origins of Nonalcoholic Fatty Liver Disease (NAFLD)

Nonalcoholic fatty liver disease (NAFLD) is a hepatic manifestation of metabolic syndrome. Its prevalence is currently increasing not only in developed obese countries but also in developing countries. Recent findings from human cohorts and animal studies suggest that a nutritional imbalance in the early critical period is causatively associated with the incidence of NAFLD in later life. Based on the current theory of the developmental origins of health and disease (DOHaD), undernourishment and overnourishment in utero are both hypothesized to prime the predisposition for hepatic fat storage. Current knowledge on the developmental origins of NAFLD is introduced in this chapter.

Uterine Artery Flow and Offspring Growth in Long-Evans Rats following Maternal Exposure to Ozone during Implantation

BACKGROUND

Epidemiological studies suggest that increased ozone exposure during gestation may compromise fetal growth. In particular, the implantation stage of pregnancy is considered a key window of susceptibility for this outcome.

OBJECTIVES

The main goals of this study were to investigate the effects of short-term ozone inhalation during implantation on fetal growth outcomes and to explore the potential for alterations in uterine arterial flow as a contributing mechanism.

METHODS

Pregnant Long-Evans rats were exposed to filtered air, 0.4 ppm ozone, or 0.8 ppm ozone for 4 h/d during implantation, on gestation days (GD) 5 and 6. Tail cuff blood pressure and uterine artery Doppler ultrasound were measured on GD 15, 19, and 21. To assess whether peri-implantation ozone exposure resulted in sustained pulmonary or systemic health effects, bronchoalveolar lavage fluid, serum metabolic and inflammatory end points, and kidney histopathology were evaluated in dams at GD 21. Growth parameters assessed in GD 21 offspring included fetal weight, length, and body composition.

RESULTS

Measures of maternal uterine arterial flow, including resistance index and mean velocity, indicated that resistance increased between GD 15 and GD 21 in 0.8 ppm dams but decreased in controls, although absolute values were similar in both groups on GD 21. Ozone-exposed dams also had lower serum glucose and higher free fatty acid concentrations than controls on GD 21. On GD 21, both male and female offspring had lower body weight than controls, and pooled subsets of 3 male and 3 female fetuses from litters exposed to 0.8 ppm ozone had lower lean mass and fat mass than pooled control offspring.

CONCLUSIONS

Findings from our experimental model suggest that the offspring of dams exposed to ozone during implantation had reduced growth compared with controls, possibly as a consequence of ozone-induced vascular dysfunction. https://doi.org/10.1289/EHP2019.

DNA methylation-independent growth restriction and altered developmental programming in a mouse model of preconception male alcohol exposure

The preconception environment is a significant modifier of dysgenesis and the development of environmentally-induced disease. To date, fetal alcohol spectrum disorders (FASDs) have been exclusively associated with maternal exposures, yet emerging evidence suggests male-inherited alterations in the developmental program of sperm may be relevant to the growth-restriction phenotypes of this condition. Using a mouse model of voluntary consumption, we find chronic preconception male ethanol exposure associates with fetal growth restriction, decreased placental efficiency, abnormalities in cholesterol trafficking, sex-specific alterations in the genetic pathways regulating hepatic fibrosis, and disruptions in the regulation of imprinted genes. Alterations in the DNA methylation profiles of imprinted loci have been identified in clinical studies of alcoholic sperm, suggesting the legacy of paternal drinking may transmit via heritable disruptions in the regulation of imprinted genes. However, the capacity of sperm-inherited changes in DNA methylation to broadly transmit environmentally-induced phenotypes remains unconfirmed. Using bisulphite mutagenesis and second-generation deep sequencing, we find no evidence to suggest that these phenotypes or any of the associated transcriptional changes are linked to alterations in the sperm-inherited DNA methylation profile. These observations are consistent with recent studies examining the male transmission of diet-induced phenotypes and emphasize the importance of epigenetic mechanisms of paternal inheritance beyond DNA methylation. This study challenges the singular importance of maternal alcohol exposures and suggests paternal alcohol abuse is a significant, yet overlooked epidemiological factor complicit in the genesis of alcohol-induced growth defects, and may provide mechanistic insight into the failure of FASD children to thrive postnatally.

Effects of medium-chain triglycerides on intestinal morphology and energy metabolism of intrauterine growth retarded weanling piglets

It has been shown that there is a relationship between intrauterine growth retardation (IUGR) and postnatal intestinal damage involved in energy deficits. Therefore, the present study was conducted to investigate the effect of medium-chain triglycerides (MCT) on the intestinal morphology, intestinal function and energy metabolism of piglets with IUGR. At weaning (21 ± 1.1 d of age), 24 IUGR piglets and 24 normal birth weight (NBW) piglets were selected according to their birth weights (BW) (IUGR: 0.95 ± 0.04 kg BW; NBW: 1.58 ± 0.04 kg BW) and their weights at the time of weaning (IUGR: 5.26 ± 0.15 kg BW; NBW: 6.98 ± 0.19 kg BW). The piglets were fed a diet of either long-chain triglycerides (LCT) (containing 5% LCT) or MCT (containing 1% LCT and 4% MCT) for 28 d. Then, the piglets' intestinal morphology, biochemical parameters and mRNA abundance related to intestinal damage and energy metabolism were determined. IUGR was found to impair intestinal morphology, with evidence of decreased villus height and increased crypt depth; however, these negative effects of IUGR were ameliorated by MCT treatment. IUGR piglets showed compromised intestinal digestion and absorption functions when compared with NBW piglets. However, feeding MCT increased the maltase activity in the jejunum and alleviated IUGR-induced reductions in plasma d-xylose concentrations and jejunal sucrase activity. IUGR decreased the efficiency of the piglets' intestinal energy metabolism; however, piglets fed an MCT diet exhibited increased adenosine triphosphate (ATP) concentrations and ATP synthase F1 complex beta polypeptide expression, as well as decreased adenosine monophosphate-activated kinase alpha 1 expression in the jejunum of piglets. In addition, up-regulation of the piglets' citrate synthase and succinate dehydrogenase levels was found to occur following MCT treatment at both the activity and the transcriptional levels of the jejunum. Therefore, it can be postulated that MCT treatment has beneficial effects in alleviating IUGR-induced intestinal morphologic damage, which is associated with improved intestinal energy metabolism.

Cord Blood Adipokines and Lipids and Adolescent Nonalcoholic Fatty Liver Disease

CONTEXT

Maternal adiposity in pregnancy is associated with offspring adiposity and metabolic dysfunction postnatally, including greater risk of nonalcoholic fatty liver disease (NAFLD). Recent genetic analyses suggest a causal effect of greater maternal body mass index on offspring birth weight and ponderal index, but the relative roles of the environment in utero or later in life remains unclear.

OBJECTIVE

We sought to determine whether markers of infant adiposity (birth weight, umbilical cord blood leptin, adiponectin, and lipids) were associated with markers of NAFLD in adolescence.

DESIGN, SETTING, AND PARTICIPANTS

This was a UK prospective birth cohort with 17 years of follow-up with liver function tests (aspartate aminotransferase, alanine aminotransferase, gamma-glutamyltransferase) (n = 1037 participants), and ultrasound scan assessed liver fat, volume, and sheer velocity at age 17 (n = 541 participants). Missing covariate data were imputed.

MAIN OUTCOMES

Ultrasound and biochemical measures of NAFLD were measured.

RESULTS

Birth weight, cord blood leptin, and adiponectin were not associated with a diagnosis of NAFLD. In adjusted analyses, 2 of 42 associations attained conventional 5% levels of significance. Birth weight was positively associated with liver volume (1.0% greater per 100 g [95% confidence interval 0.5%-2.0%]). Cord high-density lipoprotein-cholesterol was positively associated with alanine aminotransferase (11.6% higher per 1 mmol/L [95% confidence interval 0.3, 23.4]); however, this association was primarily mediated via offspring adiposity.

CONCLUSIONS

In this extensive analysis, we found little evidence measurements of infant fat mass and birth size were related to adolescent markers of NAFLD. The association between birth weight and adolescent liver volume may indicate the contribution of greater organ size to birth weight and tracking of organ size.

Effects of disturbed liver growth and oxidative stress of high-fat diet-fed dams on cholesterol metabolism in offspring mice

BACKGROUND/OBJECTIVES

Changes in nutritional status during gestation and lactation have detrimental effects on offspring metabolism. Several animal studies have shown that maternal high-fat diet (HFD) can predispose the offspring to development of obesity and metabolic diseases, however the mechanisms underlying these transgenerational effects are poorly understood. Therefore, we examined the effect of maternal HFD consumption on metabolic phenotype and hepatic expression of involved genes in dams to determine whether any of these parameters were associated with the metabolic outcomes in the offspring.

MATERIALS/METHODS

Female C57BL/6 mice were fed a low-fat diet (LFD: 10% calories from fat) or a high-fat diet (HFD: 45% calories from fat) for three weeks before mating, and during pregnancy and lactation. Dams and their male offspring were studied at weaning.

RESULTS

Dams fed an HFD had significantly higher body and adipose tissue weights and higher serum triglyceride and cholesterol levels than dams fed an LFD. Hepatic lipid levels and mRNA levels of genes involved in lipid metabolism, including LXRα, SREBP-2, FXR, LDLR, and ABCG8 were significantly changed by maternal HFD intake. Significantly lower total liver DNA and protein contents were observed in dams fed an HFD, implicating the disturbed liver adaptation in the pregnancy-related metabolic demand. HFD feeding also induced significant oxidative stress in serum and liver of dams. Offspring of dams fed an HFD had significantly higher serum cholesterol levels, which were negatively correlated with liver weights of dams and positively correlated with hepatic lipid peroxide levels in dams.

CONCLUSIONS

Maternal HFD consumption induced metabolic dysfunction, including altered liver growth and oxidative stress in dams, which may contribute to the disturbed cholesterol homeostasis in the early life of male mice offspring.

A Molecular Perspective on Procedures and Outcomes with Assisted Reproductive Technologies

The emerging association of assisted reproductive technologies with adverse perinatal outcomes has prompted the in-depth examination of clinical and laboratory protocols and procedures and their possible effects on epigenetic regulatory mechanism(s). The application of various approaches to study epigenetic regulation to problems in reproductive medicine has the potential to identify relative risk indicators for particular conditions, diagnostic biomarkers of disease state, and prognostic indicators of outcome. Moreover, when applied genome-wide, these techniques are likely to find novel pathways of disease pathogenesis and identify new targets for intervention. The analysis of DNA methylation, histone modifications, transcription factors, enhancer binding and other chromatin proteins, DNase-hypersensitivity and, micro- and other noncoding RNAs all provide overlapping and often complementary snapshots of chromatin structure and resultant "gene activity." In terms of clinical application, the predictive power and utility of epigenetic information will depend on the power of individual techniques to discriminate normal levels of interindividual variation from variation linked to a disease state. At present, quantitative analysis of DNA methylation at multiple loci seems likely to hold the greatest promise for achieving the level of precision, reproducibility, and throughput demanded in a clinical setting.

Medium-chain TAG improve energy metabolism and mitochondrial biogenesis in the liver of intra-uterine growth-retarded and normal-birth-weight weanling piglets

We previously reported that medium-chain TAG (MCT) could alleviate hepatic oxidative damage in weanling piglets with intra-uterine growth retardation (IUGR). There is a relationship between oxidative status and energy metabolism, a process involved in substrate availability and glucose flux. Therefore, the aim of this study was to investigate the effects of IUGR and MCT on hepatic energy metabolism and mitochondrial function in weanling piglets. Twenty-four IUGR piglets and twenty-four normal-birth-weight (NBW) piglets were fed a diet of either soyabean oil (SO) or MCT from 21 d of postnatal age to 49 d of postnatal age. Then, the piglets' biochemical parameters and gene expressions related to energy metabolism and mitochondrial function were determined (n 4). Compared with NBW, IUGR decreased the ATP contents and succinate oxidation rates in the liver of piglets, and reduced hepatic mitochondrial citrate synthase (CS) activity (P<0·05). IUGR piglets exhibited reductions in hepatic mitochondrial DNA (mtDNA) contents and gene expressions related to mitochondrial biogenesis compared with NBW piglets (P<0·05). The MCT diet increased plasma ghrelin concentration and hepatic CS and succinate dehydrogenase activities, but decreased hepatic pyruvate kinase activity compared with the SO diet (P<0·05). The MCT-fed piglets showed improved mtDNA contents and PPARγ coactivator-1α expression in the liver (P<0·05). The MCT diet alleviated decreased mRNA abundance of the hepatic PPARα induced by IUGR (P<0·05). It can therefore be postulated that MCT may have beneficial effects in improving energy metabolism and mitochondrial function in weanling piglets.

Late gestation under- and overnutrition have differential impacts when combined with a post-natal obesogenic diet on glucose-lactate-insulin adaptations during metabolic challenges in adolescent sheep

AIM

To determine whether late gestation under- and overnutrition programme metabolic plasticity in a similar way, and whether metabolic responses to an obesogenic diet in early post-natal life depend on the foetal nutrition history.

METHODS

In a 3 × 2 factorial design, twin-pregnant ewes were for the last 6 weeks of gestation (term = 147 days) assigned to HIGH (N = 13; 150 and 110% of energy and protein requirements, respectively), NORM (N = 9; 100% of requirements) or LOW (N = 14; 50% of requirements) diets. The twin offspring were raised on high-carbohydrate-high-fat (HCHF; N = 35) or conventional (CONV; N = 35) diets from 3 days to 6 months of age (around puberty). Then intravenous glucose (GTT; overnight fasted), insulin (ITT; fed) and propionate (gluconeogenetic precursor; PTT; both fed and fasted) tolerance tests were conducted to evaluate (hepatic) metabolic plasticity.

RESULTS

Prenatal malnutrition differentially impacted adaptations of particularly plasma lactate followed by glucose, cholesterol and insulin. This was most clearly expressed during PTT in fasted lambs and much less during ITT and GTT. In fasted lambs, propionate induced more dramatic increases in lactate than glucose, and HIGH lambs became more hyperglycaemic, hyperlactataemic and secreted less insulin compared to the hypercholesterolaemic LOW lambs. Propionate-induced insulin secretion was virtually abolished in fasted HCHF lambs, but upregulated in fasted compared to fed CONV lambs. HCHF lambs had the greatest glucose-induced insulin secretory responses.

CONCLUSION

Prenatal malnutrition differentially programmed glucose-lactate metabolic pathways and cholesterol homeostasis. Prenatal overnutrition predisposed for hyperglycaemia and hyperlactataemia, whereas undernutrition predisposed for hypercholesterolaemia upon exposure to an obesogenic diet. Prenatal overnutrition (not undernutrition) interfered with pancreatic insulin secretion by non-glucose-dependent mechanisms.

Gene-environment interactions controlling energy and glucose homeostasis and the developmental origins of obesity

Obesity and type 2 diabetes mellitus (T2DM) often occur together and affect a growing number of individuals in both the developed and developing worlds. Both are associated with a number of other serious illnesses that lead to increased rates of mortality. There is likely a polygenic mode of inheritance underlying both disorders, but it has become increasingly clear that the pre- and postnatal environments play critical roles in pushing predisposed individuals over the edge into a disease state. This review focuses on the many genetic and environmental variables that interact to cause predisposed individuals to become obese and diabetic. The brain and its interactions with the external and internal environment are a major focus given the prominent role these interactions play in the regulation of energy and glucose homeostasis in health and disease.

Functional body composition and related aspects in research on obesity and cachexia: report on the 12th Stock Conference held on 6 and 7 September 2013 in Hamburg, Germany

The 12th Stock Conference addressed body composition and related functions in two extreme situations, obesity and cancer cachexia. The concept of 'functional body composition' integrates body components into regulatory systems relating the mass of organs and tissues to corresponding in vivo functions and metabolic processes. This concept adds to an understanding of organ/tissue mass and function in the context of metabolic adaptations to weight change and disease. During weight gain and loss, there are associated changes in individual body components while the relationships between organ and tissue mass are fixed. Thus an understanding of body weight regulation involves an examination of the relationships between organs and tissues rather than individual organ and tissue masses only. The between organ/tissue mass relationships are associated with and explained by crosstalks between organs and tissues mediated by cytokines, hormones and metabolites that are coupled with changes in body weight, composition and function as observed in obesity and cancer cachexia. In addition to established roles in intermediary metabolism, cell function and inflammation, organ-tissue crosstalk mediators are determinants of body composition and its change with weight gain and loss. The 12th Stock Conference supported Michael Stocks' concept of gaining new insights by integrating research ideas from obesity and cancer cachexia. The conference presentations provide an in-depth understanding of body composition and metabolism.

Impact of intrauterine growth restriction on long-term health

PURPOSE OF REVIEW

Intrauterine growth restriction (IUGR) is responsible for the higher rates of fetal, perinatal, and neonatal morbidity and mortality. This review details the IUGR risk factors, its short and long-term sequel, the mechanism underlying the long-term consequences, and the strategies to tackle IUGR burden.

RECENT FINDINGS

Short-term consequences of IUGR involve metabolic, thermal, and hematological disturbances leading to morbidities. Long term consequences due to changes in the fetal nutritional environment is associated with increased risk of developing metabolic syndrome and cardiovascular disease, systolic hypertension, obesity, insulin resistance, and diabetes type II in adulthood. There are no effective therapies to reverse IUGR, and antenatal management is aimed at determining the ideal time and mode of delivery. In order to prevent complications associated with IUGR, it is important to first detect the condition and institute appropriate surveillance to assess fetal well-being coupled with suitable intervention in case of fetal distress.

SUMMARY

Reliable prediction of IUGR may be achieved by combining clinical risk factors with Doppler abnormalities, fetal growth, and biomarkers. If this can be achieved, there is potential to reduce future perinatal morbidity, mortality and long-term consequences, but steps geared toward the prevention of IUGR are of unparalleled importance.

Differential developmental programming by early protein restriction of rat skeletal muscle according to its fibre-type composition

AIMS

Differences in fibre-type composition of skeletal muscle have been associated with obesity and insulin resistance. As a poor nutrient environment early in life is a predisposing factor for the development of obesity and related metabolic diseases at adulthood, this study aimed at determining the long-term consequences of maternal undernutrition on the structural and metabolic properties of two skeletal muscles characterized by their different fibre-type composition and metabolic properties.

METHODS

The fibre-type composition and enzymatic activities of hexokinase (HK), beta-hydroxyacyl-CoA dehydrogenase (β-HAD) and citrate synthase (CS) were measured in soleus and extensor digitorum longus (EDL) muscles from adult rats born to dams fed a control (17% protein) or a low-protein [8% protein (PR)] diet throughout pregnancy and lactation. In addition, the expression levels of several genes regulating glycolysis, fatty acid oxidation and mitochondrial biogenesis were determined by real-time PCR.

RESULTS

Protein rats exhibited enhanced density of type II fibres along with decreased rate of fatty acid oxidation and glycolysis in soleus but not EDL. Malnourished rats exhibited also a different gene expression profile in soleus and EDL. Altogether, these alterations correspond to a state of energy deficiency and are present in animals which do not show yet any sign of obesity or glucose intolerance.

CONCLUSION

We conclude that maternal protein restriction alters in the long term the structural and enzymatic properties of offspring skeletal muscle in a fibre-type-dependent manner. These alterations might have a causative role in the development of obesity and related metabolic disorders later in life.

Association of nutrition in early life with body fat and serum leptin at adult age

BACKGROUND

There is overwhelming evidence that experiences during early life could have long-term health consequences. However, the role of early nutrition in programming obesity and leptin resistance is still poorly understood.

OBJECTIVE

We aimed at determining whether nutritional intakes in early life are associated with body composition and hormonal status at 20 years.

SUBJECTS

Healthy infants participating in the two-decade-long prospective ELANCE (Etude Longitudinale Alimentation Nutrition Croissance des Enfants) study were examined at 10 months and 2 years. At 20 years, weight, height, subscapular and triceps skinfold thicknesses, fat mass (FM) and fat-free mass (FFM) assessed via bioelectrical impedance analysis, and serum leptin concentration were recorded in 73 subjects still participating in the follow-up.

RESULTS

In adjusted linear regression models, an increase by 100 kcal in energy intake at 2 years was associated with higher subscapular skinfold thickness (β=6.4% SF, 95% confidence interval 2.53-10.30, P=0.002) and higher FFM (0.50 kg, 0.06-0.95, P=0.03) at 20 years. An increase by 1% energy from fat at 2 years was associated with lower subscapular skinfold thickness (-2.3% SF, -4.41 to -0.18, P=0.03), lower FM (-0.31 kg, -0.60 to -0.01, P=0.04) and lower serum leptin concentration (-0.21 μg l(-1), -0.39 to -0.03, P=0.02) at 20 years.

CONCLUSIONS

Low-fat intake in early life was negatively associated with body fat (particularly at the trunk site) and serum leptin concentration at 20 years, suggesting that early low-fat intake could increase the susceptibility to develop overweight and leptin resistance at later ages. These findings substantiate current recommendations against restricting fat intake in early life and open new directions for investigating the origin of obesity.