Maternal dietary fat alters amniotic fluid and fetal intestinal membrane essential n-6 and n-3 fatty acids in the rat

High-fat diet reveals the impact of Sar1b defects on lipid and lipoprotein profile and cholesterol metabolism

Biallelic pathogenic variants of the Sar1b gene cause chylomicron retention disease (CRD) whose central phenotype is the inability to secrete chylomicrons. Patients with CRD experience numerous clinical symptoms such as gastrointestinal, hepatic, neuromuscular, ophthalmic, and cardiological abnormalities. Recently, the production of mice expressing either a targeted deletion or mutation of Sar1b recapitulated biochemical and gastrointestinal defects associated with CRD. The present study was conducted to better understand little-known aspects of Sar1b mutations, including mouse embryonic development, lipid profile, and lipoprotein composition in response to high-fat diet, gut and liver cholesterol metabolism, sex-specific effects, and genotype-phenotype differences. Sar1b deletion and mutation produce a lethal phenotype in homozygous mice, which display intestinal lipid accumulation without any gross morphological abnormalities. On high-fat diet, mutant mice exhibit more marked abnormalities in body composition, adipose tissue and liver weight, plasma cholesterol, non-HDL cholesterol and polyunsaturated fatty acids than those on the regular Chow diet. Divergences were also noted in lipoprotein lipid composition, lipid ratios (serving as indices of particle size) and lipoprotein-apolipoprotein distribution. Sar1b defects significantly reduce gut cholesterol accumulation while altering key players in cholesterol metabolism. Noteworthy, variations were observed between males and females, and between Sar1b deletion and mutation phenotypes. Overall, mutant animal findings reveal the importance of Sar1b in several biochemical, metabolic and developmental processes.

Utilizing Amniotic Fluid Metabolomics to Monitor Fetal Well-Being: A Narrative Review of the Literature

Fetal and perinatal periods are critical phases for long-term development. Early diagnosis of maternal complications is challenging due to the great complexity of these conditions. In recent years, amniotic fluid has risen in a prominent position in the latest efforts to describe and characterize prenatal development. Amniotic fluid may provide real-time information on fetal development and metabolism throughout pregnancy as substances from the placenta, fetal skin, lungs, gastric fluid, and urine are transferred between the mother and the fetus. Applying metabolomics to monitor fetal well-being, in such a context, could help in the understanding, diagnosis, and treatment of these conditions and is a promising area of research. This review shines a spotlight on recent amniotic fluid metabolomics studies and their methods as an interesting tool for the assessment of many conditions and the identification of biomarkers. Platforms in use, such as proton nuclear magnetic resonance (¹H NMR) and ultra-high-performance liquid chromatography (UHPLC), have different merits, and a combinatorial approach could be valuable. Metabolomics may also be used in the quest for habitual diet-induced metabolic signals in amniotic fluid. Finally, analysis of amniotic fluid can provide information on exposure to exogenous substances by detecting the exact levels of metabolites carried to the fetus and associated metabolic effects.

Maternal High-Fat Diet Exposure During Gestation and Lactation Affects Intestinal Development in Suckling Rats

Maternal health and diet influence metabolic status and play a crucial role in the development of metabolic function in offspring and their susceptibility to metabolic diseases in adulthood. The pathogenesis of various metabolic disorders is often associated with impairment in intestinal structure and function. Thus, the aim of the current study was to determine the effects of maternal exposure to a high fat diet (HFD), during gestation and lactation, on small intestinal growth and maturation in rat pups at 21 days old. Female, Wistar Han rats were fed either a breeding diet (BD) or high fat diet (HFD), from mating until the 21st day of lactation. Maternal HFD exposure increased body weight, BMI and adiposity. Compared to the maternal BD, HFD exposure influenced small intestine histomorphometry in a segment-dependent manner, changed the activity of brush border enzymes and had an impact on intestinal contractility via changes in cholinergic signaling. Moreover, offspring from the maternal HFD group had upregulated mRNA expression of cyclooxygenase (COX)-2, which plays a role in the inflammatory process. These results suggest that maternal HFD exposure, during gestation and lactation, programs the intestinal development of the offspring in a direction toward obesity as observed changes are also commonly reported in models of diet-induced obesity. The results also highlight the importance of maternal diet preferences in the process of developmental programming of metabolic diseases.

High-fat-diet induced obesity increases the proportion of linoleic acyl residues in dam serum and milk and in suckling neonate circulation

Maternal obesity increases the risk of offspring to become obese and develop related pathologies. Exposure to maternal high-fat diet (HFD) only during lactation increases the risk of obesity-related diseases, suggesting that factors in milk affect long-term health. We hypothesized that prepregnancy obesity induced by HFD alters milk lipidome, and in turn, alterations may affect neonate serum lipidome. The objective of this study was to determine the effect of prepregnancy obesity induced by HFD on circulating lipids in dams and neonates and in milk. Female mice were fed an HFD (60% kcal fat) or control diet (CON, 10% kcal fat) beginning 4 weeks before breeding. On postnatal day 2 (PND2), pups were cross-fostered to create pup groups exposed to HFD during pregnancy, lactation, or both or exposed to CON. On PND12, dams were milked and then euthanized along with pups to collect blood. Serum and milk were processed for multiple reaction monitoring (MRM) lipidomics profiling to quantify the relative expression of lipid classes. Lipidome of HFD dam serum and milk had increased proportion of C18:2 free fatty acid and fatty acyl residues in all lipid classes. Lipidome of serum from pups exposed to maternal HFD during lactation was similarly affected. Thus, maternal HFD induced redistribution of fatty acyl residues in the dam’s circulation, which was associated with modification in milk and suckling neonate’s lipidome. Further studies are needed to determine if increased circulating levels of C18:2 in neonate affects development and predisposes offspring to obesity and metabolic syndrome.

Epigenetics and the Developmental Origins of Health and Disease: Parental environment signalling to the epigenome, critical time windows and sculpting the adult phenotype

The literature about Developmental Origins of Health and Disease (DOHaD) studies is considerably growing. Maternal and paternal environment, during all the development of the individual from gametogenesis to weaning and beyond, as well as the psychosocial environment in childhood and teenage, can shape the adult and the elderly person's susceptibility to her/his own environment and diseases. This non-conventional, non-genetic, inheritance is underlain by several mechanisms among which epigenetics is obviously central, due to the notion of memory of early decisional events during development even when this stimulus is gone, that is implied in Waddington's developmental concept. This review first summarizes the different mechanisms by which the environment can model the epigenome: receptor signalling, energy metabolism and signal mechanotransduction from extracellular matrix to chromatin. Then an overview of the epigenetic changes in response to maternal environment during the vulnerability time windows, gametogenesis, early development, placentation and foetal growth, and postnatal period, is described, with the specific example of overnutrition and food deprivation. The implication of epigenetics in DOHaD is obvious, however the precise causal chain from early environment to the epigenome modifications to the phenotype still needs to be deciphered.

Maternal high-fat diet exposure during gestation, lactation, or gestation and lactation differentially affects intestinal morphology and proteome of neonatal mice

Offspring nutrition depends on the mother during gestation and lactation; thus, maternal nutrition and metabolism can affect their development. We hypothesized that maternal exposure to high-fat (HF) diet affects neonate's gastrointestinal tract development. Our objective was to determine the effect of maternal HF diet during gestation and lactation on neonate's duodenum histomorphology and proteome. Female mice were fed either a control (C, 10% kcal fat) or an HF (60% kcal fat) diet for 4 weeks and bred. On postnatal day 2, half the pups were cross-fostered to dams fed on different diet, creating 4 treatments: C-C, C-HF, HF-C, and HF-HF, indicating maternal diet during gestation-lactation, respectively. On postnatal day 12, pups' duodenum was excised and prepared for histology and liquid chromatography-tandem mass spectrometry analysis of proteome. Villi were significantly longer in HF-HF pups, and crypt cell proliferation rate was not different among treatments. Between C-C and HF-HF, HF-C, or C-HF, 812, 601, or 894 proteins were differentially expressed (Tukey adjusted P < .05), respectively. Functional analysis clustered proteins upregulated in HF-HF vs C-C in fat digestion and absorption, extracellular matrix, cell adhesion, immune response, oxidation-reduction processes, phagocytosis, and transport categories. Proteins downregulated were classified as RNA splicing, translation, protein folding, endocytosis, and transport. There was evidence for a carryover effect of exposure to HF diet during gestation to the postnatal period. Alterations in proteome relative to HF exposure potentially reflect long-term changes in the functioning of the duodenum.

1H NMR-based metabolomics reveals the effect of maternal habitual dietary patterns on human amniotic fluid profile

Maternal diet may influence offspring’s health, even within well-nourished populations. Amniotic fluid (AF) provides a rational compartment for studies on fetal metabolism. Evidence in animal models indicates that maternal diet affects AF metabolic profile; however, data from human studies are scarce. Therefore, we have explored whether AF content may be influenced by maternal diet, using a validated food-frequency questionnaire and implementing NMR-based metabolomics. Sixty-five AF specimens, from women undergoing second-trimester amniocentesis for prenatal diagnosis, were analysed. Complementary, maternal serum and urine samples were profiled. Hierarchical cluster analysis identified 2 dietary patterns, cluster 1 (C1, n = 33) and cluster 2 (C2, n = 32). C1 was characterized by significantly higher percentages of energy derived from refined cereals, yellow cheese, red meat, poultry, and “ready-to-eat” foods, while C2 by higher (P < 0.05) whole cereals, vegetables, fruits, legumes, and nuts. ¹H NMR spectra allowed the identification of metabolites associated with these dietary patterns; glucose, alanine, tyrosine, valine, citrate, cis-acotinate, and formate were the key discriminatory metabolites elevated in C1 AF specimens. This is the first evidence to suggest that the composition of AF is influenced by maternal habitual dietary patterns. Our results highlight the need to broaden the knowledge on the importance of maternal nutrition during pregnancy.

Fate of orally administered radioactive fatty acids in the late-pregnant rat

To investigate the biodisponibility of placental transfer of fatty acids, rats pregnant for 20 days were given tracer amounts of [(14)C]palmitic (PA), oleic (OA), linoleic (LA), α-linolenic (LNA), or docosahexaenoic acid (DHA) orally and euthanized at 0.5, 1.0, 2.0, or 8.0 h thereafter. Maternal plasma radioactivity in lipids initially increased only to decline at later times. Most of the label appeared first as triacylglycerols (TAG); later, the proportion in phospholipids (PhL) increased. The percentage of label in placental lipids was also always highest shortly after administration and declined later; again, PhL increased with time. Fetal plasma radioactivity increased with time, with its highest value at 8.0 h after DHA or LNA administration. DHA initially appeared primarily in the nonesterified fatty acids (NEFA) and PA, OA, LA, and LNA as TAG followed by NEFA; in all cases, there was an increase in PhL at later times. Measurement of fatty acid concentrations allowed calculation of specific (radio)activities, and the ratio (fetal/maternal) of these in the plasmas gave an index of placental transfer activity, which was LNA > LA > DHA = OA > PA. It is proposed that a considerable proportion of most fatty acids transferred through the placenta are released into the fetal circulation in the form of TAG.

Cross-generational trans fat intake exacerbates UV radiation-induced damage in rat skin

We evaluated the influence of dietary fats on ultraviolet radiation (UVR)-induced oxidative damage in skin of rats. Animals from two consecutive generations born of dams supplemented with fats during pregnancy and breastfeeding were maintained in the same supplementation: soybean-oil (SO, rich in n-6 FA, control group), fish-oil (FO, rich in n-3 FA) or hydrogenated-vegetable-fat (HVF, rich in TFA). At 90 days of age, half the animals from the 2nd generation were exposed to UVR (0.25 J/cm(2)) 3×/week for 12 weeks. The FO group presented higher incorporation of n-3 FA in dorsal skin, while the HVF group incorporated TFA. Biochemical changes per se were observed in skin of the HVF group: greater generation of reactive oxygen species (ROS), lower mitochondrial integrity and increased Na(+)K(+)-ATPase activity. UVR exposure increased skin wrinkles scores and ROS generation and decreased mitochondrial integrity and reduced-glutathione levels in the HVF group. In FO, UVR exposure was associated with smaller skin thickness and reduced levels of protein-carbonyl, together with increased catalase activity and preserved Na(+)K(+)-ATPase function. In conclusion, while FO may be protective, trans fat may be harmful to skin health by making it more vulnerable to UVR injury and thus more prone to develop photoaging and skin cancer.

The origin of fetal sterols in second-trimester amniotic fluid: endogenous synthesis or maternal-fetal transport?

OBJECTIVE

Cholesterol is crucial for fetal development. To gain more insight into the origin of the fetal cholesterol pool in early human pregnancy, we determined cholesterol and its precursors in the amniotic fluid of uncomplicated, singleton human pregnancies.

STUDY DESIGN

Total sterols were characterized by gas chromatography-mass spectrometry in the second-trimester amniotic fluid of 126 healthy fetuses from week 15 until week 22.

RESULTS

The markers of cholesterol biosynthesis, lanosterol, dihydrolanosterol, and lathosterol, were present in low levels until the 19th week of gestation, after which their levels increased strongly. β-sitosterol, a marker for maternal-fetal cholesterol transport, was detectable in the amniotic fluid. The total cholesterol levels increased slightly between weeks 15 and 22.

CONCLUSION

Our results support the hypothesis that during early life the fetus depends on maternal cholesterol supply because endogenous synthesis is relatively low. Therefore, maternal cholesterol can play a crucial role in fetal development.

Recent advances in small bowel diseases: Part I

As is the case in all parts of gastroenterology and hepatology, there have been many advances in our knowledge and understanding of small intestinal diseases. Over 1000 publications were reviewed for 2008 and 2009, and the important advances in basic science as well as clinical applications were considered. In Part I of this Editorial Review, seven topics are considered: intestinal development; proliferation and repair; intestinal permeability; microbiotica, infectious diarrhea and probiotics; diarrhea; salt and water absorption; necrotizing enterocolitis; and immunology/allergy. These topics were chosen because of their importance to the practicing physician.

Metabolic development in the liver and the implications of the n-3 fatty acid supply

The n-3 fatty acids contribute to regulation of hepatic fatty acid oxidation and synthesis in adults and accumulate in fetal and infant liver in variable amounts depending on the maternal diet fat composition. Using 2D gel proteomics and matrix-assisted laser desorption/ionization time of flight mass spectrometry, we recently identified altered abundance of proteins associated with glucose and amino acid metabolism in neonatal rat liver with increased n-3 fatty acids. Here, we extend studies on n-3 fatty acids in hepatic metabolic development to targeted gene and metabolite analyses and map the results into metabolic pathways to consider the role of n-3 fatty acids in glucose, fatty acid, and amino metabolism. Feeding rats 1.5% compared with <0.1% energy 18:3n-3 during gestation led to higher 20:5n-3 and 22:6n-3 in 3-day-old offspring liver, higher serine hydroxymethyltransferase, carnitine palmitoyl transferase, and acyl CoA oxidase and lower pyruvate kinase and stearoyl CoA desaturase gene expression, with higher cholesterol, NADPH and glutathione, and lower glycine (P < 0.05). Integration of the results suggests that the n-3 fatty acids may be important in facilitating hepatic metabolic adaptation from in utero nutrition to the postnatal high-fat milk diet, by increasing fatty acid oxidation and directing glucose and amino acids to anabolic pathways.

The role of amniotic fluid in influencing neonatal birth weight

OBJECTIVE

We studied 123 neonates with atresias of the gastrointestinal tract at different levels to assess the role of amniotic fluid in the growth and development of the gastrointestinal tract. Our hypothesis was that significant differences in birth weight between groups otherwise comparable would suggest an intrauterine nutritive role for amniotic fluid. Our second hypothesis was that there is a trophic role of amniotic fluid on intestinal epithelium affecting its functional maturity. Establishing earlier tolerance of enteral nutrition in neonates with distal as compared with proximal atresias would support this hypothesis.

STUDY DESIGN

Overall, 123 neonates from a single institution, with duodenal atresia (DA), jejuno-ileal (JIA) and colonic atresia (CA), were separated into three groups. Birth weight, gestational age, associated anomalies and duration of total parenteral nutrition intake were recorded. Neonates with multiple atresias and gastroschisis were excluded from analysis. Statistical analysis of differences between groups was carried out using analysis of variance (ANOVA) for independent samples. Post-ANOVA pairwise comparisons were carried out using the Tukey-HSD test.

RESULT

Fifty-four DAs, 62 JIAs and seven CAs were included. The mean birth weight, 2380.5 g (s.d. 988) in DA, 2814 g (s.d. 755) in JIA and 3153 g (s.d. 527) in CA were significantly different between groups (P=0.011). The Tukey-HSD test showed that DA<JIA<CA was also significant (P<0.01). The mean gestational age (Tukey-HSD test, P=not significant (NS)) and presence of associated anomalies (Wilcoxson, P=0.08) did not differ significantly among the groups. Total parenteral nutrition was stopped at a mean period of 18 days in DA, 15.6 days in JIA and 15.6 days in CA (Tukey-HSD, P=NS).

CONCLUSION

Proximal atresias have a significantly lower birth weight than atresias distal in the gastrointestinal tract. This cannot be explained on the basis of gestational age or associated anomalies. Although not conclusive, this study implies an intrauterine nutritive role for amniotic fluid. Further studies are needed to prove the trophic effects of amniotic fluid on the gut.

Linseed oil in the maternal diet during gestation and lactation modifies fatty acid composition, mucosal architecture, and mast cell regulation of the ileal barrier in piglets

In this study, we investigated the effect of supplementation of the maternal diet with linseed oil [rich in 18:3(n-3)] on fatty acid composition, mucosal architecture, and mast cell regulation of barrier function in piglet ileum. Sixteen sows were fed a lard (LAR)- or a linseed oil (LSO)-based diet during gestation and lactation. Fatty acid composition of maternal RBC at parturition and of milk at d 14 of lactation were determined. Fatty acid composition, villous-crypt structure, and permeability to horseradish peroxidase in Ussing chambers after mast cell degranulation were determined in the ileum of piglets at d 0, 7, and 28. At d 0, 18:3(n-3) and 20:5(n-3) levels were higher, but 22:6(n-3) and 20:4(n-6) levels were lower in both maternal RBC and piglet ileum of the LSO group. Levels of 18:3(n-3) were also higher in the milk of LSO sows. Levels of 18:3(n-3) were higher in LSO piglet ileum at d 7 and 28. Moreover, at d 28, 20:4(n-6) ileal levels tended (P = 0.09) to be lower in LSO than in LAR piglets, in parallel with a lower mRNA expression of Delta5 desaturase. LSO piglets had shorter villi at d 0 and shorter crypts at d 7 compared with LAR piglets. The effect of mast cell degranulation on ileal permeability decreased with age in both groups but reached a minimum sooner in the LSO group (d 7) than in the LAR group (d 28). In conclusion, linseed oil supplementation of the maternal diet profoundly modifies the fatty acid composition, structure, and physiology of the offspring ileum.

High vitamin intake by Wistar rats during pregnancy alters tissue fatty acid concentration in the offspring fed an obesogenic diet

Diet during pregnancy affects the long-term health of the offspring. Vitamins are known to modulate lipid metabolism, which may be reflected in tissue fatty acid (FA) concentrations. The objective of this study was to investigate the effect of high vitamin intake during pregnancy on tissue FA concentration of the offspring. Wistar rats were fed an AIN-93G diet with either the recommended vitamin or 10-fold higher amounts (HV) during pregnancy. Afterward, offspring were weaned onto an obesogenic diet. Liver, quadriceps, adipose, and brain were collected over 48 weeks. Fatty acid concentration of tissue total lipids was analyzed by gas chromatography. At birth, the liver from HV offspring was higher in monounsaturated, stearic, and arachidonic acids. At weaning, the liver from HV offspring was higher in stearic and oleic acids; and in adipose tissue, n-6 and n-3 FAs were lower only in the male HV offspring (P < .05). At 12 weeks, HV offspring had higher concentrations of total fat, saturates, monounsaturates, and n-6 FA in muscle (P < .05), but not in other tissues. At 48 weeks, gestational diet did not affect tissue total lipid FA concentrations; but differences remained in specific tissue phospholipids species. Liver phospholipids from HV offspring were lower in monounsaturates and n-6 FA. Brain phosphatidylethanolamine was higher in oleic, n-6 FA, and docosahexaenoic acid in the HV offspring. Phosphatidylinositol was lower in saturates, monounsaturates, arachidonic, and docosahexaenoic acids only in HV female offspring. These observations demonstrate that high vitamin intake during pregnancy has short- and long-term effects on tissue FA concentration in the offspring.

[Effects of omega 3 supplementation in pregnant women]

Maternal nutrition is a major environmental factor, which can be modified and can affect fetal growth and development with potential long-term consequences. There is currently a strong mediatic pressure for supplementing diets with omega 3 fatty acids. Nevertheless, if beneficial effects seem to be confirmed in adults and in animal models, the evidence for favourable effects of omega 3 supplementation in pregnant women are less obvious. Indeed, there is a trend showing a positive effect on cerebral development, but long term effects have not been demonstrated and both the quantity of omega 3 and the omega 3:omega 6 ratios are not precisely determined. Numerous studies are needed, both in pregnant animal models and in patients, to unravel these effects.

Dietary lipids in early development and intestinal inflammatory disease

Inflammatory bowel diseases are life-long reoccurring inflammatory disorders of the gastrointestinal tract and have been increasing in incidence in recent decades, notably in the pediatric population. Although genetic predisposition remains an important factor, this increased incidence most likely reflects an environmental change. One potential contributor to this is the change in dietary fat intake, with dietary intake of n-6 polyunsaturated fatty acids (PUFAs) following a similar temporal pattern to the change in inflammatory bowel disease incidence. Dietary n-6 PUFAs comprise a major, modifiable, environmental factor known to promote a heightened inflammatory response through a number of pathways, including their role as precursors for synthesis of eicosanoids and their inhibitory effect on the synthesis of the n-3 PUFAs eicosapentanoic acid and docosahexanoic acid. The increase in n-6 PUFA intake affects individuals of all ages, with fetal PUFA accretion and infant dietary PUFA intake from breast milk reflecting maternal dietary intake. A high level of n-6 PUFA in milk results in increased n-6 PUFA in colonic phospholipids and an exaggerated inflammatory response to chemically induced colitis. Conversely, during development, a diet low in n-6 PUFAs and high in n-3 PUFAs increases colonic n-3 fatty acids, attenuates the inflammatory response, and lowers colonic damage. High dietary n-6 PUFA intake may be an important environmental modifier that contributes to inflammatory bowel diseases.

Impact of dietary fatty acids on oocyte quality and development in lactating dairy cows

The purpose of this study was to examine the effects of level of rumen inert fatty acids on developmental competence of oocytes in lactating dairy cows. Estrous cycles were synchronized in 22 cows on a silage-based diet supplemented with either low (200 g/day) or high (800 g/day) fat. A total of 1051 oocytes were collected by ultrasound-guided ovum pickup (OPU) in seven sessions/cow at 3-4 day intervals. Oocytes were matured, fertilized, and cultured to the blastocyst stage in vitro. Embryo quality was assessed by differential staining of Day 8 blastocysts. The high-fat diet reduced numbers of small and medium follicles. There was no effect on the quality of oocytes (grades 1-4) or cleavage rate. However, high fat significantly improved blastocyst production from matured (P < 0.005) and cleaved (P < 0.05) oocytes. Blastocysts from the high-fat group had significantly more total, inner cell mass and trophectoderm cells than the low-fat group (P < 0.05). Regression analysis showed negative effects of milk yield (P < 0.001), dry matter intake (P < 0.001), metabolizable energy intake (P < 0.005), and starch intake (P < 0.001) on blastocyst production in the low-fat group but not in the high-fat group. Within the low-fat group, blastocyst production was negatively related to growth hormone (P < 0.05) and positively related to leptin (P < 0.05). The low-fat group had higher nonesterified fatty acids than the high-fat group (P < 0.05). In conclusion, higher milk yields were associated with reduced developmental potential of oocytes in cows given a low-fat diet. Provision of a high-fat diet buffered oocytes against these effects, resulting in significantly improved developmental potential.