Placental delivery of arachidonic and docosahexaenoic acids: implications for the lipid nutrition of preterm infants

Physiological response to fetal intravenous lipid emulsion

In preterm neonates unable to obtain sufficient oral nutrition, intravenous lipid emulsion is life-saving. The contribution of post-conceptional level of maturation to pathology that some neonates experience is difficult to untangle from the global pathophysiology of premature birth. In the present study, we determined fetal physiological responses to intravenous lipid emulsion. Fetal sheep were given intravenous Intralipid 20® (n = 4 females, 7 males) or Lactated Ringer's Solution (n = 7 females, 4 males) between 125 ± 1 and 133 ± 1 d of gestation (term = 147 d). Manufacturer's recommendation for premature human infants was followed: 0.5-1 g/kg/d initial rate, increased by 0.5-1 to 3 g/kg/d. Hemodynamic parameters and arterial blood chemistry were measured, and organs were studied postmortem. Red blood cell lipidomics were analyzed by LC-MS. Intravenous Intralipid did not alter hemodynamic or most blood parameters. Compared with controls, Intralipid infusion increased final day plasma protein (P=0.004; 3.5 ± 0.3 vs. 3.9 ± 0.2 g/dL), albumin (P = 0.031; 2.2 ± 0.1 vs. 2.4 ± 0.2 g/dL), and bilirubin (P<0.001; conjugated: 0.2 ± 0.1 vs. 0.6 ± 0.2 mg/dL; unconjugated: 0.2 ± 0.1 vs. 1.1 ± 0.4 mg/dL). Circulating IGF-1 decreased following Intralipid infusion (P<0.001; 66 ± 24 vs. 46 ± 24 ng/mL). Compared with control Oil Red O liver stains (median score 0), Intralipid-infused fetuses scored 108 (P=0.0009). Lipidomic analysis revealed uptake and processing of infused lipids into red blood cells, increasing abundance of saturated fatty acids. The near-term fetal sheep tolerates intravenous lipid emulsion well, although lipid accumulates in the liver. Increased levels of unconjugated bilirubin may reflect increased red blood cell turnover or impaired placental clearance. Whether Intralipid is less well tolerated earlier in gestation remains to be determined.

Linoleic and Arachidonic Fatty Acids and their Potential Relationship with Inflammation, Pregnancy, and Fetal Development

A healthy maternal diet must consider an appropriate supply of long-chain polyunsaturated fatty acids (LCPUFAs) precursors to ensure adequate growth and development of the fetus. In this regard, n-6 PUFAs, predominantly linoleic (C18:2 n-6, LA) and arachidonic acid (C20:4 n-6), have a central role in the development of the central nervous system because they are part of the membrane structure and participate in the metabolism and signal transduction of cells. Nevertheless, they can also be transformed into inflammatory metabolites promoting the pathogenesis of cardiovascular diseases, cancer, and autoimmune or inflammatory conditions. In modern westernized societies, there is a high dietary consumption of foods rich in n-6 PUFAs which could have detrimental consequences for the fetus and neonate due to excessive exposure to these fatty acids (FAs).

OBJECTIVE

To summarize the evidence of maternal, placental, and fetal alterations that an excessive intake of n-6 polyunsaturated FAs (PUFAs), LA, and AA, could produce during pregnancy.

METHODS

A thorough review of the literature regarding the effects of n-6 PUFAs during pregnancy and lactation including in vivo and in vitro models, was carried out using the PubMed database from the National Library of Medicine-National Institutes of Health.

RESULTS

An elevated intake of n-6 PUFA, specifically LA, during pregnancy influences children's motor, cognitive, and verbal development during infancy and early childhood. Similarly, they could harm the placenta and the development of other fetal organs such as the fat tissue, liver, and cardiovascular system.

CONCLUSION

Maternal diet, specifically LA intake, could have significant repercussions on fetal development and long-term consequences in the offspring, including the possibility of future metabolic and mental diseases. It would be necessary to focus on the prevention of these alterations through timely dietary interventions in the target population.

Enteral Nutrition in Preterm Infants (2022): A Position Paper From the ESPGHAN Committee on Nutrition and Invited Experts

OBJECTIVES

To review the current literature and develop consensus conclusions and recommendations on nutrient intakes and nutritional practice in preterm infants with birthweight <1800 g.

METHODS

The European Society of Pediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN) Committee of Nutrition (CoN) led a process that included CoN members and invited experts. Invited experts with specific expertise were chosen to represent as broad a geographical spread as possible. A list of topics was developed, and individual leads were assigned to topics along with other members, who reviewed the current literature. A single face-to-face meeting was held in February 2020. Provisional conclusions and recommendations were developed between 2020 and 2021, and these were voted on electronically by all members of the working group between 2021 and 2022. Where >90% consensus was not achieved, online discussion meetings were held, along with further voting until agreement was reached.

RESULTS

In general, there is a lack of strong evidence for most nutrients and topics. The summary paper is supported by additional supplementary digital content that provide a fuller explanation of the literature and relevant physiology: introduction and overview; human milk reference data; intakes of water, protein, energy, lipid, carbohydrate, electrolytes, minerals, trace elements, water soluble vitamins, and fat soluble vitamins; feeding mode including mineral enteral feeding, feed advancement, management of gastric residuals, gastric tube placement and bolus or continuous feeding; growth; breastmilk buccal colostrum, donor human milk, and risks of cytomegalovirus infection; hydrolyzed protein and osmolality; supplemental bionutrients; and use of breastmilk fortifier.

CONCLUSIONS

We provide updated ESPGHAN CoN consensus-based conclusions and recommendations on nutrient intakes and nutritional management for preterm infants.

Myo-Inositol Moderates Glucose-Induced Effects on Human Placental 13C-Arachidonic Acid Metabolism

Maternal hyperglycemia is associated with disrupted transplacental arachidonic acid (AA) supply and eicosanoid synthesis, which contribute to adverse pregnancy outcomes. Since placental inositol is lowered with increasing glycemia, and since myo-inositol appears a promising intervention for gestational diabetes, we hypothesized that myo-inositol might rectify glucose-induced perturbations in placental AA metabolism. Term placental explants (n = 19) from women who underwent a mid-gestation oral glucose-tolerance-test were cultured with 13C-AA for 48 h in media containing glucose (5, 10 or 17 mM) and myo-inositol (0.3 or 60 µM). Newly synthesized 13C-AA-lipids were quantified by liquid-chromatography-mass-spectrometry. Increasing maternal fasting glycemia was associated with decreased proportions of 13C-AA-phosphatidyl-ethanolamines (PE, PE-P), but increased proportions of 13C-AA-triacylglycerides (TGs) relative to total placental 13C-AA lipids. This suggests altered placental AA compartmentalization towards storage and away from pools utilized for eicosanoid production and fetal AA supply. Compared to controls (5 mM glucose), 10 mM glucose treatment decreased the amount of four 13C-AA-phospholipids and eleven 13C-AA-TGs, whilst 17 mM glucose increased 13C-AA-PC-40:8 and 13C-AA-LPC. Glucose-induced alterations in all 13C-AA lipids (except PE-P-38:4) were attenuated by concurrent 60 µM myo-inositol treatment. Myo-inositol therefore rectifies some glucose-induced effects, but further studies are required to determine if maternal myo-inositol supplementation could reduce AA-associated pregnancy complications.

Phytochemical Compositions of Some Red Sea Halophyte Plants with Antioxidant and Anticancer Potentials

The aim of this study was to determine the compositions of carbohydrates, phenolic compounds, fatty acids (FAs), and amino acids (AAs) of four Rea Sea halophytes: Anabasis ehrenbergii, Suaeda aegyptiaca, Suaeda monoica, and Zygophyllum album. The results showed that S. aegyptiaca and S. monoica were rich in gallic acid with 41.72 and 47.48 mg/g, respectively, while A. ehrenbergii was rich in naringenin with 11.88 mg/g. The polysaccharides of the four species were mainly composed of galactose (54.74%) in A. ehrenbergii, mannose (44.15%) in S. aegyptiaca, glucose and ribose (33 and 26%, respectively) in S. monoica, and arabinose and glucose (36.67 and 31.52%, respectively) in Z. album. Glutamic acid and aspartic acid were the major AAs in all halophyte species with 50–63% and 10–22% of the total AAs, respectively. The proportion of unsaturated fatty acids (UFA) of the four species was 42.18–55.33%, comprised mainly of linolenic acid (15.54–28.63%) and oleic acid (5.68–22.05%), while palmitic acid (23.94–49.49%) was the most abundant saturated fatty acid (SFA). Phytol and 9,19-cyclolanost-24-en-3β–ol represented the major unsaponifiable matter (USM) constituents of S. monoica and A. ehrenbergii with proportions 42.44 and 44.11%, respectively. The phenolic fraction of S. aegyptiaca and S. monoica demonstrated noteworthy antioxidant activity with IC₅₀ values of 9.0 and 8.0 μg/mL, respectively, while the FAs fraction of Z. album exhibited potent cytotoxic activity against Huh-7, A-549, and Caco-2 cancer cell lines with IC₅₀ values of 7.4, 10.8, and 11.8 μg/mL, respectively. Our results indicate that these plants may be considered a source of naturally occurring compounds with antioxidant and anticancer effects that could be suitable for future applications.

Morbidity Outcomes of Very Low Birth Weight Neonates Receiving Parenteral Nutrition with Fish Oil Enriched Lipid Emulsion or Lipid Emulsion with Soybean Oil: An Observational Study

Intralipid (Fresenius Kabi) was the most commonly used lipid emulsion in parenteral nutrition (PN), with a 100% soybean oil composition, a low vitamin E content, and a ω-6: ω-3 ratio of 7:1. A recent alternative formulation is SMOFlipid (Fresenius Kabi), with a ω-6: ω-3 ratio of 5:2 and higher vitamin E content. A retrospective observational study was conducted to determine neonatal morbidity in very low birth weight (VLBW) premature infants during two periods: P1, when PN was based exclusively on Intralipid, and P2, when only SMOFlipid was supplied. In total, 170 VLBW neonates were analyzed, of whom 103 received PN for more than 6 days, 56 during P1, and 47 during P2. In both periods, the antenatal and neonatal characteristics of the cohort were comparable. In this analysis, the prevalence of associated comorbidities was determined. During P2, there were fewer cases of moderate to severe bronchopulmonary dysplasia (BPD) and of cholestasis, but more cases of late sepsis, mainly Staphylococcus epidermidis. No changes in the prevalence of other neonatal comorbidities were observed. We believe that the SMOFlipid used in PN could discreetly improve the prevalence of cholestasis or BPD.

Maternal Supplementation with Cow's Milk Naturally Enriched with PUFA Alters the Metabolism of Sows and the Fatty Acid Profile of the Offspring

The study aimed to evaluate the supplementation of gilts with cow's milk naturally enriched with n-3 and n-6 polyunsaturated fatty acids (PUFA) on reproductive outcomes, and the serum biochemical and FA profile of swine females and their offspring. During 316 days, 30 gilts were distributed into three groups: (1) Control, fed a basal diet + milk from cows without oil; (2) n-3, fed a basal diet + milk from cows fed a diet enriched with linseed oil; (3) n-6, fed a basal diet + milk from cows fed a diet enriched with soybean oil. The gilts receiving the diets containing PUFA had higher serum urea and very-low-density lipoprotein levels and lower serum total protein and low-density lipoprotein levels compared to the Control group. Females supplemented with n-3 presented higher serum palmitic acid and γ-linolenic acid levels than those fed n-6. Piglets from the Control group were heavier at birth than those from females supplemented with enriched milk. The piglets from females receiving enriched milk had 140 g higher body weight from 1 to 21 days old compared to the Control group, and greater average daily weight gain from 7 to 14 days old. The serum eicosapentaenoic acid level of piglets fed n-3 was 69% higher than those fed n-6, which reduced the AA/EPA ratio. Gilts supplemented with PUFA-enriched cow's milk showed changes in their serum palmitic and γ-linolenic acid levels, in addition to improved performance, EPA concentration and consequently reduced AA/EPA ratio in their piglets, demonstrating beneficial results for their progeny.

Association of Maternal Microbiota and Diet in Cord Blood Cytokine and Immunoglobulin Profiles

Mothers confer natural passive immunization to their infants through the transplacental pathway during the gestation period. The objective of the present study was to establish at birth the maternal and cord plasma concentration and relationship of immunoglobulins (Igs), cytokines (CKs), and adipokines. In addition, the impact of the maternal microbiota and diet was explored. The plasma profile of these components was different between mothers and babies, with the levels of many CKs, IgM, IgG2a, IgE, IgA, and leptin significantly higher in mothers than in the cord sample. Moreover, the total Igs, all IgG subtypes, IgE, and the Th1/Th2 ratio positively correlated in the mother–infant pair. Maternal dietary components such as monounsaturated fatty acids-polyunsaturated fatty acids and fiber were positively associated with some immune factors such as IgA in cord samples. The microbiota composition clustering also influenced the plasma profile of some factors (i.e., many CKs, some Ig, and adiponectin). In conclusion, we have established the concentration of these immunomodulatory factors in the maternal–neonatal pair at birth, some positive associations, and the influence of maternal diet and the microbiota composition, suggesting that the immune status during pregnancy, in terms of CKs and Igs levels, can influence the immune status of the infant at birth.

Lipid Composition, Digestion, and Absorption Differences among Neonatal Feeding Strategies: Potential Implications for Intestinal Inflammation in Preterm Infants

Necrotizing enterocolitis (NEC) is a significant cause of morbidity and mortality in the neonatal population. Formula feeding is among the many risk factors for developing the condition, a practice often required in the cohort most often afflicted with NEC, preterm infants. While the virtues of many bioactive components of breast milk have been extolled, the ability to digest and assimilate the nutritional components of breast milk is often overlooked. The structure of formula differs from that of breast milk, both in lipid composition and chemical configuration. In addition, formula lacks a critical digestive enzyme produced by the mammary gland, bile salt-stimulated lipase (BSSL). The gastrointestinal system of premature infants is often incapable of secreting sufficient pancreatic enzymes for fat digestion, and pasteurization of donor milk (DM) has been shown to inactivate BSSL, among other important compounds. Incompletely digested lipids may oxidize and accumulate in the distal gut. These lipid fragments are thought to induce intestinal inflammation in the neonate, potentially hastening the development of diseases such as NEC. In this review, differences in breast milk, pasteurized DM, and formula lipids are highlighted, with a focus on the ability of those lipids to be digested and subsequently absorbed by neonates, especially those born prematurely and at risk for NEC.

Maternal and child fatty acid desaturase genotype as determinants of cord blood long-chain PUFA (LCPUFA) concentrations in the Seychelles Child Development Study

Optimal maternal long-chain PUFA (LCPUFA) status is essential for the developing fetus. The fatty acid desaturase (FADS) genes are involved in the endogenous synthesis of LCPUFA. The minor allele of various FADS SNP have been associated with increased maternal concentrations of the precursors linoleic acid (LA) and α-linolenic acid (ALA), and lower concentrations of arachidonic acid (AA) and DHA. There is limited research on the influence of FADS genotype on cord PUFA status. The current study investigated the influence of maternal and child genetic variation in FADS genotype on cord blood PUFA status in a high fish-eating cohort. Cord blood samples (n 1088) collected from the Seychelles Child Development Study (SCDS) Nutrition Cohort 2 (NC2) were analysed for total serum PUFA. Of those with cord PUFA data available, maternal (n 1062) and child (n 916), FADS1 (rs174537 and rs174561), FADS2 (rs174575), and FADS1-FADS2 (rs3834458) were determined. Regression analysis determined that maternal minor allele homozygosity was associated with lower cord blood concentrations of DHA and the sum of EPA + DHA. Lower cord blood AA concentrations were observed in children who were minor allele homozygous for rs3834458 (β = 0·075; P = 0·037). Children who were minor allele carriers for rs174537, rs174561, rs174575 and rs3834458 had a lower cord blood AA:LA ratio (P < 0·05 for all). Both maternal and child FADS genotype were associated with cord LCPUFA concentrations, and therefore, the influence of FADS genotype was observed despite the high intake of preformed dietary LCPUFA from fish in this population.

A review of the role of inositols in conditions of insulin dysregulation and in uncomplicated and pathological pregnancy

Inositols, a group of 6-carbon polyols, are highly bioactive molecules derived from diet and endogenous synthesis. Inositols and their derivatives are involved in glucose and lipid metabolism and participate in insulin-signaling, with perturbations in inositol processing being associated with conditions involving insulin resistance, dysglycemia and dyslipidemia such as polycystic ovary syndrome and diabetes. Pregnancy is similarly characterized by substantial and complex changes in glycemic and lipidomic regulation as part of maternal adaptation and is also associated with physiological alterations in inositol processing. Disruptions in maternal adaptation are postulated to have a critical pathophysiological role in pregnancy complications such as gestational diabetes and pre-eclampsia. Inositol supplementation has shown promise as an intervention for the alleviation of symptoms in conditions of insulin resistance and for gestational diabetes prevention. However, the mechanisms behind these affects are not fully understood. In this review, we explore the role of inositols in conditions of insulin dysregulation and in pregnancy, and identify priority areas for research. We particularly examine the role and function of inositols within the maternal-placental-fetal axis in both uncomplicated and pathological pregnancies. We also discuss how inositols may mediate maternal-placental-fetal cross-talk, and regulate fetal growth and development, and suggest that inositols play a vital role in promoting healthy pregnancy.

Administration of an Intravenous Fat Emulsion Enriched with Medium-Chain Triglyceride/ω-3 Fatty Acids is Beneficial Towards Anti-Inflammatory Related Fatty Acid Profile in Preterm Neonates: A Randomized, Double-Blind Clinical Trial

Intravenous administration of pure soybean oil emulsions high in linoleic acid may lead to inflammation and lipid peroxidation in preterm neonates. We aimed to investigate the effects of a medium-chain triglyceride (MCT)/ω-3 polyunsaturated fatty acid (PUFA)-enriched intravenous fat emulsion (IVFE) on plasma fatty acid (FA) profile and serum interleukin-6 (IL-6) in preterm neonates. In this double-blind randomized study, 92 preterm neonates (gestational age < 32 weeks, birth weight < 1500 g) were assigned to receive either MCT/ω-3 PUFA-enriched IVFE (Intervention Group) or soybean oil-based IVFE (Control Group). Levels of FAs were measured at baseline (day 0) and day 15 of parenteral nutrition with gas-chromatography mass-spectrometry. Serum IL-6 was measured with sandwich ELISA in 59 neonates. Plasma FAs changed significantly over time; the MCT/ω-3 PUFA-IVFE group showed higher ω-3 PUFAs (p = 0.031), eicosapentaenoic acid (p = 0.000), and oleic acid (p = 0.003), and lower ω-6/ω-3 PUFAs ratio (p = 0.001) and ω-6 PUFAs (p = 0.023) compared to control group. Linoleic acid was higher in the soybean oil (SO)-based IVFE arm compared to the MCT/ω-3 PUFAs-IVFE arm (p = 0.006). Both fat emulsion types decreased IL-6 compared to baseline, but changes were insignificant between groups. Administration of MCT/ω-3 PUFA-enriched IVFE in preterm neonates is beneficial in changing the FA profile consistent with attenuated inflammatory response.

Fatty acids of human milk - a review

The composition of human milk is the result of the evolution of mammals over millions of years. Among the most important components of milk are fatty acids. Approximately 85% are saturated and monounsaturated fatty acids - the rest are polyunsaturated one. Their role is to provide energy and immunity and to serve as buildings blocks, as well as assisting the hormonal system and the metabolism of fats, carbohydrates and proteins. The structural differences between fatty acids determine their biodiversity and give them particular physiological importance. Correct development of the nervous system, retina and other structures depend on an adequate supply of both these fatty acids during intrauterine development and in the newborn and infant stages. The fats present in milk form milk fat globules - structures that do not appear in milk formula prepared using vegetable oils. Apart from the mother's diet, other sources of fatty acids are endogenous biosynthesis in the mammary gland and the fat deposits from which the fatty acids are released. Evolution of the mother's body has also created adaptive mechanisms that adjust the amount of fatty acids in milk to the state of health and needs of the child. These mechanisms go some way to creating a buffer with regard to dietary shortages experienced by pregnant/breastfeeding women, and optimalise the composition of milk fatty acids depending on the age of the pregnant woman, the birth weight of the infant and the efficiency of the placenta during pregnancy.

Resilience to Freezing in the Vegetative Cells of the Microalga Lobosphaera incisa (Trebouxiophyceae, Chlorophyta)

The chlorophyte microalga Lobosphaera incisa was isolated from the snowy slopes of Mt. Tateyama in Japan. This microalga stores exceptionally high amounts of the omega-6 LC-PUFA arachidonic acid in triacylglycerols, and therefore represents a potent photosynthetic source for this essential LC-PUFA. Assuming that freezing tolerance may play a role in adaptation of L. incisa to specific ecological niches, we examined the capability of L. incisa to tolerate extreme sub-zero temperatures. We report here, that the vegetative cells of L. incisa survived freezing at -20°C and -80°C (over 1 month), without cryoprotective agents or prior treatments. Cells successfully recovered upon thawing and proliferated under optimal growth conditions (25°C). However, cells frozen at -80°C showed better recovery and lower cellular ROS generation upon thawing, compared to those preserved at -20°C. Photosynthetic yield of PSII, estimated by F_v /F_m , temporarily decreased at day 1 post freezing and resumed to the original level at day 3. Interestingly, the thawed algal cultures produced a higher level of chlorophylls, exceeding the control culture. The polar metabolome of the vegetative cells comprised a range of compatible solutes, dominated by glutamate, sucrose, and proline. We posit that the presence of endogenous cryoprotectants, a rigid multilayer cell wall, the high LC-PUFA content in membrane lipids, and putative cold-responsive proteins may contribute to the retention of functionality upon recovery from the frozen state, and therefore for the survival under cryospheric conditions. From the applied perspective, this beneficial property holds promise for the cryopreservation of starter cultures for research and commercial purposes.

Association of Retinopathy of Prematurity With Low Levels of Arachidonic Acid: A Secondary Analysis of a Randomized Clinical Trial

Importance

Mice with oxygen-induced retinopathy fed matched diets except for ω-3 long-chain polyunsaturated fatty acids (LC-PUFAs) vs ω-6 LC-PUFAs demonstrate relative antiangiogenic and neuroprotective associations of ω-3 LC-PUFAs. However, supplementing preterm infants with LC-PUFAs has been inconsistent in reducing major preterm morbidities. However, few studies measured serum lipid levels after supplementation.

Objective

To examine the associated risk of retinopathy of prematurity (ROP) from the levels of circulating ω-3 and ω-6 LC-PUFAs.

Design, Setting, and Participants

This longitudinal clinical study was a further analysis of serum lipid levels from a randomized controlled trial cohort of 90 infants born at gestational age (GA) less than 28 weeks. From April 4, 2013, to September 22, 2015, cord blood samples, followed by venous blood samples, were obtained at birth and at 1, 7, 14, and 28 days after birth and then at postmenstrual age (PMA) 32, 36, and 40 weeks at the neonatal intensive care unit at Sahlgrenska University Hospital in Göteborg, Sweden.

Main Outcomes and Measures

Serum phospholipid fatty acids were transmethylated and measured by gas chromatography-mass spectrometry. Mann-Whitney test, logistic regression Spearman rank correlation, and receiver operating characteristic curve analysis were used to compare differences between infants with no ROP and infants who developed ROP.

Results

Serum levels from 78 infants (43 male [55%]; mean [SD] GA, 25.5 [1.4] weeks) with a known ROP outcome were evaluated. Lower area under the curve (AUC) of arachidonic acid (AA) (20:4 ω-6) was seen in infants with a later diagnosis of ROP compared with infants with no ROP in the first month of life (mean, 34.05 [95% CI, 32.10-36.00] vs 37.15 [95% CI, 34.85-39.46]; P < .05). In addition, lower levels of AA at 32 weeks' PMA were seen in infants with later severe ROP compared with in those without ROP (mean, 7.06 [95% CI, 6.60-7.52] vs 8.74 [95% CI, 7.80-9.67]; P < .001). In logistic modeling, low postnatal serum levels of AA and GA at birth identified with a sensitivity greater than 90% of infants who developed ROP.

Conclusions and Relevance

Low postnatal levels of the ω-6 LC-PUFAs (AA) are strongly associated with ROP development. Evaluating postnatal AA fraction after birth in addition to GA may be useful for ROP prediction.

Trial Registration

clinicaltrials.gov Identifier: NCT02760472.

Combined choline and DHA supplementation: a randomized controlled trial

OBJECTIVE

Choline and docosahexaenoic acid (DHA) are essential nutrients for preterm infant development. They are metabolically linked via phosphatidylcholine (PC), a constitutive plasma membrane lipid and the major transport form of DHA in plasma. Plasma choline and DHA-PC concentrations rapidly decline after preterm birth. To improve preterm infant nutrition, we evaluated combined compared to exclusive choline and DHA supplementation, and standard feeding.

DESIGN

Randomized partially blinded single-center trial.

SETTING

Neonatal tertiary referral center in Tübingen, Germany.

PATIENTS

24 inborn preterm infants < 32 week postmenstrual age.

INTERVENTIONS

Standard nutrition (control) or, additionally, enteral choline (30 mg/kg/day), DHA (60 mg/kg/day), or both for 10 days. Single enteral administration of 3.6 mg/kg [methyl-D₉-] choline chloride as a tracer at 7.5 days.

MAIN OUTCOME MEASURES

Primary outcome variable was plasma choline following 7 days of supplementation. Deuterated and unlabeled choline metabolites, DHA-PC, and other PC species were secondary outcome variables.

RESULTS

Choline supplementation increased plasma choline to near-fetal concentrations [35.4 (32.8-41.7) µmol/L vs. 17.8 (16.1-22.4) µmol/L, p < 0.01] and decreased D₉-choline enrichment of PC. Single DHA treatment decreased DHA in PC relative to total lipid [66 (60-68)% vs. 78 (74-80)%; p < 0.01], which was prevented by choline. DHA alone increased DHA-PC only by 35 (26-45)%, but combined treatment by 63 (49-74)% (p < 0.001). D₉-choline enrichment showed preferential synthesis of PC containing linoleic acid. PC synthesis via phosphatidylethanolamine methylation resulted in preferential synthesis of DHA-containing D₃-PC, which was increased by choline supplementation.

CONCLUSIONS

30 mg/kg/day additional choline supplementation increases plasma choline to near-fetal concentrations, dilutes the D₉-choline tracer via increased precursor concentrations and improves DHA homeostasis in preterm infants.

TRIAL REGISTRATION

clinicaltrials.gov. Identifier: NCT02509728.

Randomized controlled trial of brain specific fatty acid supplementation in pregnant women increases brain volumes on MRI scans of their newborn infants

Docosahexaenoic acid (DHA) and arachidonic acid (ArA) are essential brain specific fatty acids (BSFA) for mammalian central nervous system development. Human brains have accelerated growth with significant increase in cerebral content of ArA and DHA during the last trimester of pregnancy and first postnatal months. This randomized double blind placebo controlled single centre trial assessed the impact of BSFA supplementation in pregnancy on newborn infants' brain volumes. Eighty six infants born to study mothers had brain magnetic resonance imaging (MRI) scans soon after birth. Total and regional brain volumes were analyzed and related to maternal supplementation group. Males born to the BSFA supplemented mothers had significantly larger total brain volumes, total gray matter, corpus callosum and cortical volumes when compared to the placebo group. This is the first study to show maternal BSFA supplementation enhances newborn infants' brain size and suggests differential sex sensitivity of fetal brains to pregnancy BSFA status.

Distribution of Fatty Acids and Lipids During Pregnancy

Maternal fatty acid and lipid metabolism undergoes changes during pregnancy to facilitate fetal growth and development. Different types of fatty acids have different roles in maintaining a successful pregnancy and they are incorporated into different forms of lipids for the purpose of storage and transport. This chapter aims to provide an understanding of the distribution and metabolism of fatty acids and lipids in the maternal, placental, and fetal compartments. We further describe how this distribution is altered in maternal obesity, preterm birth, and pregnancy complications such as gestational diabetes mellitus, preeclampsia, and intrauterine growth restriction.

Supplementing dams with both arachidonic and docosahexaenoic acid has beneficial effects on growth and immune development

Omega-3 long-chain polyunsaturated fatty acids (LCPUFAS) modulate immune cells in vitro and in vivo. This study investigated the effects of enriching the maternal diet with the n-6 and n-3 LCPUFAs, arachidonic (20:4n-6, 0.6%wt ARA) and docosahexaenoic acid (22:6n-3, 0.32%wt DHA), or 1:1 and 2:1 ratios (ARA: DHA) on total lipids in milk, total lipids, and immunophenotypes in plasma, lymph nodes, and spleen from isolated immune cells from 28d old pups. From day 15 of gestation to day 3 pp, Sprague-Dawley dams were fed a commercial chow. On day 3 pp litters were culled and pups (4 males and 2 females) randomly cross-fostered to dams who were randomized to one of the 5 experimental diets resulting in 20 male and 10 female pups/diet group. Dams fed ARA or ARA: DHA had 28-36% more 20:4n-6 in milk and feeding DHA or ARA: DHA doubled 22:6n-3 in milk lipids (P<0.05). Feeding 1:1 or 2:1 ARA: DHA resulted in greater pup weight at weaning (P<0.05). Compared to the control pups, ARA + DHA fed pups had a lower proportion of splenic CD45RA+ lymphocytes. In summary, postpartum supplementation with a combination of ARA + DHA, compared to ARA or DHA alone, resulted in a higher content of ARA and DHA in dam's milk and tissues and had positive effects on growth, accompanied by evidence of progression toward a mature immune phenotype, and suggests a need for ARA when DHA is supplemented in the early diet. Additional investigations are needed of ARA immunomodulation to better understand and estimate nutritional requirements for LCPUFAs during early development.

Effects of a lipid emulsion containing fish oil on polyunsaturated fatty acid profiles, growth and morbidities in extremely premature infants: A randomized controlled trial

BACKGROUND & AIMS

The purpose of the study was to compare the effects of the parenteral emulsion SMOFlipid^®, with 15% fish oil, with Clinoleic^® on retinopathy of prematurity (ROP) and other morbidities and growth, and to compare their impact on longitudinal serum levels of fatty acids. Retinopathy of prematurity, other morbidity and growth were correlated with each parenteral lipid supplement.

METHODS

Ninety infants born at gestational age <28 weeks were randomized to treatment with SMOFlipid^® or Clinoleic^®. Two thirds (66%) of the infants received parenteral nutrition for up to 14 days birth (median 8, range 2-14 days), and additional 25% of the infants received for up to 28 days after birth (median 21, range 15-28 days). Cord blood samples and then venous blood samples were obtained at ages 1, 7, 14, and 28 days and at postmenstrual age (PMA) 32, 36, and 40 weeks. Breastmilk was collected at postnatal day 7, and at PMA 32 and 40 weeks. Serum phospholipid and breastmilk total fatty acids were analyzed by gas chromatography-mass spectrometry. Treatment groups were compared with regard to ROP, bronchopulmonary dysplasia, necrotizing enterocolitis, patent ductus arteriosus sepsis and growth between birth and 36 weeks.

RESULTS

Infants on SMOFlipid^® had higher fractions of omega-3 LCPUFA eicosapentaenoic acid (EPA) and slightly higher omega-3 LCPUFA docosahexaenoic acid (DHA) fraction and a decreased arachidonic acid (AA) to DHA ratio from one week after birth up to 32 postmenstrual weeks compared to infants on Clinoleic^®. Treatment groups did not differ in morbidities or growth.

CONCLUSION

Supplementation with SMOFlipid^® containing 15% fish oil during parenteral nutrition increased EPA substantially, DHA marginally, reduced AA and decreased AA to DHA ratio. It did not reduce morbidity or affect growth. Since extremely preterm infants accumulate a large deficit of DHA and AA, studies on more prolonged or different levels of DHA and AA supplementation are warranted.

Flaxseed used since pregnancy by the mother and after weaning by the offspring benefits the retina and optic nerve development in rats

OBJECTIVE

This study aimed to evaluate the influence of a diet based on flaxseed upon the development of the nervous system, more specifically, the optic nerve and retina.

METHODS

Rats were divided into three groups: Control (CG), Flaxseed (FG), and Modified Control (MCG). The analyses were performed in the offspring (n = 6/group) at the immediate postnatal period (P0), 14 d of life (P14) and 30 d of life (P30). Descriptive analysis and histomorphometry of optic nerve and retina were performed.

RESULTS

There was a great evolution in the development of the nervous fascicles, connective trabeculae, and blood vessels, when comparing the three ages studied, and these characteristics were more evident in FG at all three ages. The P0, P14, and P30 retina showed similar morphology to that described in the literature. In histomorphometry, at P14, the FG presented the retina and its layers with significant increase in thickness, except for internal granular and ganglionar, whereas MCG had greater retina and photoreceptor layers thickness, inner plexiform and external granular when compared with CG (p < .05).

CONCLUSION

The use of flaxseed in the pre-and postnatal period displays favourable influence on the development of rat optic nerve and retina, probably leading to myelination.

The influence of placental metabolism on fatty acid transfer to the fetus

The factors determining fatty acid transfer across the placenta are not fully understood. This study used a combined experimental and computational modeling approach to explore placental transfer of nonesterified fatty acids and identify the rate-determining processes. Isolated perfused human placenta was used to study the uptake and transfer of 13C-fatty acids and the release of endogenous fatty acids. Only 6.2 ± 0.8% of the maternal 13C-fatty acids taken up by the placenta was delivered to the fetal circulation. Of the unlabeled fatty acids released from endogenous lipid pools, 78 ± 5% was recovered in the maternal circulation and 22 ± 5% in the fetal circulation. Computational modeling indicated that fatty acid metabolism was necessary to explain the discrepancy between uptake and delivery of 13C-fatty acids. Without metabolism, the model overpredicts the fetal delivery of 13C-fatty acids 15-fold. Metabolic rate was predicted to be the main determinant of uptake from the maternal circulation. The microvillous membrane had a greater fatty acid transport capacity than the basal membrane. This study suggests that incorporation of fatty acids into placental lipid pools may modulate their transfer to the fetus. Future work needs to focus on the factors regulating fatty acid incorporation into lipid pools.

Cord Blood Metabolome Is Highly Associated with Birth Weight, but Less Predictive for Later Weight Development

BACKGROUND/AIMS

Fetal metabolism may be changed by the exposure to maternal factors, and the route to obesity may already set in utero. Cord blood metabolites might predict growth patterns and later obesity. We aimed to characterize associations of cord blood with birth weight, postnatal weight gain, and BMI in adolescence.

METHODS

Over 700 cord blood samples were collected from infants participating in the German birth cohort study LISAplus. Glycerophospholipid fatty acids (GPL-FA), polar lipids, non-esterified fatty acids (NEFA), and amino acids were analyzed with a targeted, liquid chromatography-tandem mass spectrometry based metabolomics platform. Cord blood metabolites were related to growth factors by linear regression models adjusted for confounding variables.

RESULTS

Cord blood metabolites were highly associated with birth weight. Lysophosphatidylcholines C16:1, C18:1, C20:3, C18:2, C20:4, C14:0, C16:0, C18:3, GPL-FA C20:3n-9, and GPL-FA C22:5n-6 were positively related to birth weight, while higher cord blood concentrations of NEFA C22:6, NEFA C20:5, GPL-FA C18:3n-3, and PCe C38:0 were associated with lower birth weight. Postnatal weight gain and BMI z-scores in adolescents were not significantly associated with cord blood metabolites after adjustment for multiple testing.

CONCLUSION

Potential long-term programming effects of the intrauterine environment and metabolism on later health cannot be predicted with profiling of the cord blood metabolome.

Delta-6 desaturase activity during the first year of life in preterm infants

Term neonates have high delta-6 desaturase (D6D) activity, which is important for regulating polyunsaturated fatty acid's (PUFA) nutritional status. The aim was to investigate D6D activity in preterm infants and its postnatal changes. Forty-three appropriate-for-gestational-age infants were included. PUFA in red blood cells was analyzed at birth and at one, six, and 12 months of age. D6D activity was estimated by 20:3n-6/18:2n-6 ratio. At birth, preterm infants had D6D activity as high as that of term infants; D6D activity declined to about one-third at one month, then further decreased to about one-sixth at six months and remained stable until 12 months. The postnatal change in arachidonic acid exhibited a similar pattern to that of D6D activity; however, docosahexaenoic acid showed a transient decrease at one month and recovered to the cord blood level at six months. D6D may regulate PUFA profile in preterm infants, especially during the early postnatal period.

Docosahexaenoic Acid in Neural Signaling Systems

Docosahexaenoic acid has been conserved in neural signalling systems in the cephalopods, fish, amphibian, reptiles, birds, mammals, primates and humans. This extreme conservation, despite wide genomic changes over 500 million years, testifies to a uniqueness of this molecule in the brain. The brain selectively incorporates docosahexaenoic acid and its rate of incorporation into the developing brain has been shown to be greater than ten times more efficient than its synthesis from the omega 3 fatty acids of land plant origin. Data has now been published demonstrating a significant influence of dietary omega 3 fatty acids on neural gene expression. As docosahexaenoic acid is the only omega 3 fatty acid in the brain, it is likely that it is the ligand involved. The selective uptake, requirement for function and stimulation of gene expression would have conferred an advantage to a primate which separated from the chimpanzees in the forests and woodlands and sought a different ecological niche. In view of the paucity of docosahexaenoic acid in the land food chain it is likely that the advantage would have been gained from a lacustrine or marine coastal habitat with access to food rich in docosahexaenoic acid and the accessory micronutrients, such as iodine, zinc, copper, manganese and selenium, of importance in brain development and protection against peroxidation. Land agricultural development has, in recent time, come to dominate the human food chain. The decline in use and availability of aquatic resources is not considered important by Langdon (2006) as he considers the resource was not needed for human evolution and can be replaced from the terrestrial food chain. This notion is not supported by the biochemistry nor the molecular biology. He misses the point that the shoreline hypothesis is not just dependent on docosahexaenoic acid but also on the other accessory nutrients specifically required by the brain. Moreover he neglects the basic principle of Darwinian evolution. The well documented greater efficiency of preformed docosahexaenoic acid for brain incorporation during development would have conferred a distinct survival advantage over those without it. All terrestrial mammals lost brain capacity in relation to advancing increase in body size. The rise in mental ill health and brain disorders, to replace all other costs in the European list of burdens of ill health, (Andlin Sobocki et al., 2005) raises interesting questions as to its association with the reduced availability and consumption of marine and fresh water products. The threat posed by the continued rise in brain disorders also raises questions of importance to present and future food and agricultural policies.

Higher omega-3 index and DHA status in pregnant women compared to lactating women - Results from a German nation-wide cross-sectional study

INTRODUCTION

During pregnancy and lactation, there is a high need of long-chain (LC) omega-3 fatty acids (n-3 PUFA), especially docosahexaenoic acid (DHA), for fetus and infant. Also, a low LC n-3 PUFA status during pregnancy is associated with postpartum depression. The aim of this cross-sectional study was to analyze the LC n-3 PUFA status in German women during pregnancy and lactation.

MATERIAL AND METHODS

As a part of a nationwide cross-sectional study in which the nutrient status of women in different stages of life was determined, 213 pregnant (≥27th week of gestation) and 127 lactating women between 18 and 44 years were evaluated regarding their LC n-3 PUFA status by measuring the omega-3 index (relative eicosapentaenoic acid (EPA) and DHA concentration in erythrocyte fatty acid).

RESULTS

The mean omega-3 index of the total study population was 6.23±1.48%. Pregnant women showed significant (p≤0.001) higher omega-3 index values (6.40±1.31%) and DHA concentrations (5.91±1.23%) than lactating women (omega-3 index: 5.50±1.34%; DHA: 4.79±1.27%). Woman with LC n-3 PUFA supplementation showed higher omega-3 index values (7.73±1.28%) vs. women without supplementation (6.04±1.39%, p≤0.001). Week of pregnancy, month of lactation as well as smoking were negatively associated with the omega-3 index.

CONCLUSION

Comprehensive data on the long-term LC n-3 PUFA status of German women during pregnancy and lactation are presented. To evaluate an optimal maternal omega-3 index in view of the fetal and infant development further studies are needed.

Choline and polyunsaturated fatty acids in preterm infants' maternal milk

BACKGROUND

Choline, docosahexaenoic acid (DHA), and arachidonic acid (ARA) are essential to fetal development, particularly of the brain. These components are actively enriched in the fetus. Deprivation from placental supply may therefore result in impaired accretion in preterm infants.

OBJECTIVE

To determine choline, choline metabolites, DHA, and ARA in human breast milk (BM) of preterm infants compared to BM of term born infants.

DESIGN

We collected expressed BM samples from 34 mothers (N = 353; postnatal day 6-85), who had delivered 35 preterm infants undergoing neonatal intensive care (postmenstrual age 30 weeks, range 25.4-32.0), and from mothers after term delivery (N = 9; postnatal day 6-118). Target metabolites were analyzed using tandem mass spectrometry and gas chromatography and reported as medians and 25th/75th percentiles.

RESULTS

In BM, choline was mainly present in the form of phosphocholine and glycerophosphocholine, followed by free choline, phosphatidylcholine, sphingomyelin, and lyso-phosphatidylcholine. In preterm infants' BM total choline ranged from 61 to 360 mg/L (median: 158 mg/L) and was decreased compared to term infants' BM (range 142-343 mg/L; median: 258 mg/L; p < 0.01). ARA and DHA comprised 0.81 (range: 0.46-1.60) and 0.43 (0.15-2.42) % of total preterm BM lipids, whereas term BM values were 0.68 (0.52-0.88) and 0.35 (0.18-0.75) %, respectively. Concentrations of all target parameters decreased after birth, and frequently 150 ml/kg/d BM did not meet the estimated fetal accretion rates.

CONCLUSIONS

Following preterm delivery, BM choline concentrations are lower, whereas ARA and DHA levels are comparable versus term delivery. Based on these findings we suggest a combined supplementation of preterm infants' BM with choline, ARA and DHA combined to improve the nutritional status of preterm infants.

STUDY REGISTRATION

This study was registered at www.clinicaltrials.gov. Identifier: NCT01773902.

Effects of obesity and gestational diabetes mellitus on placental phospholipids

Gestational diabetes mellitus (GDM) is associated with adverse effects in the offspring. The composition of placental glycerophospholipids (GPL) is known to be altered in GDM and might reflect an aberrant fatty acid transfer across the placenta and thus affect the foetal body composition. The aim of this study was to investigate possible effects of obesity and GDM, respectively, on placental GPL species composition. We investigated molecular species of phosphatidylcholine (PC), phosphatidylethanolamine (PE) and phosphatidylserine (PS) in term placentas from controls (lean non-diabetic, body-mass-index [BMI] 18-24.9k g/m(2), n=31), obese non-diabetics (BMI ≥30 kg/m(2), n=17) and lean diabetics (n=15), using liquid chromatography - triple quadrupole mass spectrometry. PE(16:0/22:6) and PE(18:0/20:4) were increased in GDM and decreased species were PC(18:0/20:3), PC(18:1/20:3) and PS(18:0/18:2). A consistent difference between BMI related changes and changes caused by GDM was not observed. Arachidonic acid percentages of cord blood correlated with placental PC(16:0/20:4), whereas foetal docosahexaenoic acid correlated to placental PE species. Furthermore, a positive correlation of placental weight was found to levels of PE containing arachidonic acid. We demonstrated that obesity and GDM are associated with decreased dihomo-gamma-linolenic acid and increased arachidonic acid and docosahexaenoic acid contents of placental GPL, with unknown consequences for the foetus. PC(16:0/20:4) was identified as the major component for the supply of arachidonic acid to the foetal circulation, whereas PE containing arachidonic acid was found to be associated to the placental and infant growth.

Influence of cafeteria diet and fish oil in pregnancy and lactation on pups' body weight and fatty acid profiles in rats

PURPOSE

The aim was to determine the effects of cafeteria diet (CD) and fish oil supplements given to pregnant and lactating rats on the birth weight and fatty acid profiles of their offspring.

METHODS

Female rats were given standard diet (STD) or CD for 22 days before pregnancy. After mating, some animals remained on STD or CD; for some CD rats, the diet was supplemented with 8.78 % fish oil (CD-FO). After 12 days, half the CD-FO group returned to CD (CD-FO12) and the others remained on CD-FO.

RESULTS

At birth, body weights of pups of the three CD groups were lower than STD, maintained until 21 days in the CD-FO group only. At the end of lactation, dams of the CD groups had increased plasma triacylglycerols (TAG), non-esterified fatty acids, and glycerol concentrations, whereas most n-6 long-chain polyunsaturated fatty acids (LCPUFA) were decreased, the effect being greatest in the CD-FO group, where most n-3 LCPUFA were increased and indices of Δ(5) and Δ(6) desaturase activities decreased. The 21-day-old pups of the CD group had increased plasma TAG, not present in the CD-FO group, which had increased 3-hydroxybutyrate concentrations. In both 2- and 21-day-old CD pups, plasma concentrations of ARA were lower than STD, and even lower in the two CD-FO groups.

CONCLUSIONS

The effect of CD and CD-FO decreasing pups body weight could be related to decreased concentrations of ARA, caused by the inhibition of the Δ(5) and Δ(6) desaturases in the pathway of n-6 LCPUFA biosynthesis.

Evaluating intra- and inter-individual variation in the human placental transcriptome

BACKGROUND

Gene expression variation is a phenotypic trait of particular interest as it represents the initial link between genotype and other phenotypes. Analyzing how such variation apportions among and within groups allows for the evaluation of how genetic and environmental factors influence such traits. It also provides opportunities to identify genes and pathways that may have been influenced by non-neutral processes. Here we use a population genetics framework and next generation sequencing to evaluate how gene expression variation is apportioned among four human groups in a natural biological tissue, the placenta.

RESULTS

We estimate that on average, 33.2%, 58.9%, and 7.8% of the placental transcriptome is explained by variation within individuals, among individuals, and among human groups, respectively. Additionally, when technical and biological traits are included in models of gene expression they each account for roughly 2% of total gene expression variation. Notably, the variation that is significantly different among groups is enriched in biological pathways associated with immune response, cell signaling, and metabolism. Many biological traits demonstrate correlated changes in expression in numerous pathways of potential interest to clinicians and evolutionary biologists. Finally, we estimate that the majority of the human placental transcriptome exhibits expression profiles consistent with neutrality; the remainder are consistent with stabilizing selection, directional selection, or diversifying selection.

CONCLUSIONS

We apportion placental gene expression variation into individual, population, and biological trait factors and identify how each influence the transcriptome. Additionally, we advance methods to associate expression profiles with different forms of selection.

Fatty Acid Binding Protein 3 Is Involved in n-3 and n-6 PUFA transport in mouse trophoblasts

BACKGROUND

Low placental fatty acid (FA) transport during the embryonic period has been suggested to result in fetal developmental disorders and various adult metabolic diseases, but the molecular mechanism by which FAs are transported through the placental unit remains largely unknown.

OBJECTIVE

The aim of this study was to examine the distribution and functional relevance of FA binding protein (FABP), a cellular chaperone of FAs, in the mouse placenta.

METHODS

We clarified the localization of FABPs and sought to examine their function in placental FA transport through the phenotypic analysis of Fabp3-knockout mice.

RESULTS

Four FABPs (FABP3, FABP4, FABP5, and FABP7) were expressed with spatial heterogeneity in the placenta, and FABP3 was dominantly localized to the trophoblast cells. In placentas from the Fabp3-knockout mice (both sexes), the transport coefficients for linoleic acid (LA) were significantly reduced compared with those from wild-type mice by 25% and 44% at embryonic day (E) 15.5 and E18.5, respectively, whereas those for α-linolenic acid (ALA) were reduced by 19% and 17%, respectively. The accumulation of LA (18% and 27% at E15.5 and E18.5) and ALA (16% at E15.5) was also significantly less in the Fabp3-knockout fetuses than in wild-type fetuses. In contrast, transport and accumulation of palmitic acid (PA) were unaffected and glucose uptake significantly increased by 23% in the gene-ablated mice compared with wild-type mice at E18.5. Incorporation of LA (51% and 52% at 1 and 60 min, respectively) and ALA (23% at 60 min), but not PA, was significantly less in FABP3-knockdown BeWo cells than in controls, whereas glucose uptake was significantly upregulated by 51%, 50%, 31%, and 33% at 1, 20, 40, and 60 min, respectively.

CONCLUSIONS

Collectively FABP3 regulates n-3 (ω-3) and n-6 (ω-6) polyunsaturated FA transport in trophoblasts and plays a pivotal role in fetal development.

Metabolic conversion of intra-amniotically-injected deuterium-labeled essential fatty acids by fetal rats following maternal n-3 fatty acid deficiency

Accumulation of polyunsaturated fatty acids (PUFA) in the fetal brain is accomplished predominantly via a highly selective flow of docosahexaenoic acid (22:6n-3, DHA) and arachidonic acid (20:4n-6, AA) through the placenta. Little is known regarding the endogenous capability of the fetus to generate its own DHA and AA from lower homologues such as linolenic (18:3n-3, ALA) and linoleic (18:2n-6, LA) acids, respectively. Deuterium-labeled d5-ALA and d5-LA at millimolar concentrations were injected directly into the amniotic fluid in order to investigate maternal-independent metabolic conversion of the stable isotopes in brain and liver of the fetus near delivery. After 48h under adequate maternal diet, the levels of d5-ALA metabolites in the fetal brain and fetal liver were 45±2.2 pmol/mg and 86±4 pmol/mg of which 79% and 63.6% were comprised of d5-DHA. At this time point, incorporation of d5-LA metabolites was 103±5 pmol/mg and 772±46 pmol/mg for brain and liver, of which 50% and 30% were comprised of d5-AA. Following sustained maternal dietary ALA deficiency, the levels of total d5-ALA derived metabolites in the fetal brain and fetal liver were increased to 231 pmol/mg and 696 pmol/mg of which 71% and 26% were comprised of d5-DHA. From the time course and relative rates of d5-ALA precursor displacement by d5-DHA in cellular phosphoglycerides, it is concluded that the fetal rat brain can generate its own DHA from its d5-ALA precursors particularly under dietary stress.

Four amino acid residues influence the substrate chain-length and regioselectivity of Siganus canaliculatus Δ4 and Δ5/6 desaturases

Although ω3- and ω6- desaturases have been well studied in terms of substrate preference and regiospecificity, relatively little is known about the membrane-bound, "front-end" long chain fatty acid desaturases, such as ∆4, Δ5 or Δ6 desaturases. The first vertebrate ∆4 desaturase was recently identified in the marine teleost fish Siganus canaliculatus (S. canaliculatus), which also possesses a bifunctional Δ5/6 desaturase. These two long chain polyunsaturated fatty acid desaturases are very different in terms of regiospecificity and substrate chain-length, but share an unusually high degree of amino acid identity (83 %). We took advantage of this similarity by constructing a series of chimeric enzymes, replacing regions of one enzyme with the corresponding sequence of the other. Heterologous expression of the chimeric series of enzymes in yeast indicated that the substitution of a four amino acid region was sufficient to convert a ∆4 desaturase to an enzyme with ∆6 desaturase activity, and convert a ∆5/6 desaturase to an enzyme with a low level of ∆4 desaturase activity. In addition, enzymes having both ∆4 and ∆6 desaturase activities were produced by single or double amino acid substitutions within this four-amino acid region.

Plasma phospholipids indicate impaired fatty acid homeostasis in preterm infants

BACKGROUND

During fetal development, docosahexaenoic (DHA) and arachidonic acid (ARA) are particularly enriched in brain phospholipids. After preterm delivery, fetal enrichment of DHA and ARA via placental transfer is replaced by enteral and parenteral nutrition, which is rich in linoleic acid (LA) instead. Specific DHA and ARA enrichment of lipoproteins is reflected by plasma phosphatidylcholine (PC) species, whereas plasma phosphatidylethanolamine (PE) composition reflects hepatic stores.

OBJECTIVE

We profiled PC and PE species in preterm infant plasma, compared with cord and maternal blood, to assess whether current feeding practice meets fetal conditions in these patients.

DESIGN

Preterm infant plasma (N = 171, 23-35 w postmenstrual age (PMA), postnatal day 1-103), cord plasma (N = 194) and maternal serum (N = 121) (both 24-41 w PMA) were collected. After lipid extraction, PC and PE molecular species were analyzed using tandem mass spectrometry.

RESULTS

Phospholipid concentrations were higher in preterm infant than in cord plasma after correction for PMA. This was mainly due to postnatal increases in LA-containing PC and PE, resulting in decreased fractions of their DHA- and ARA-containing counterparts. These changes in preterm infant plasma phospholipids occurred during the time of transition to full enteral feeds (day 0-10 after delivery). Thereafter, the fraction of ARA-containing phospholipids further decreased, whereas that of DHA slowly reincreased but remained at a level 50% of that of PMA-matched cord blood.

CONCLUSIONS

The postnatal increase in LA-PC in preterm infant plasma results in decreased fractions of DHA-PC and ARA-PC. These changes are also reflected by PE molecular composition as an indicator of altered hepatic fatty acid homeostasis. They are presumably caused by inadequately high LA, and low ARA and DHA supply, at a stage of development when ARA-PC and DHA-PC should be high, probably reducing the availability of DHA and ARA to the developing brain and contributing to impaired neurodevelopment of preterm infants.

Prenatal exposure to methylmercury and LCPUFA in relation to birth weight

BACKGROUND

Epidemiologic studies have been inconclusive regarding the impact of coexposure to long chain polyunsaturated fatty acids (LCPUFA) and methylmercury (MeHg) from fish consumption during pregnancy on measures of fetal development.

OBJECTIVES

We evaluated the association between birth weight and prenatal maternal LCPUFA status and MeHg exposure in the Republic of Seychelles.

METHODS

We measured LCPUFA in maternal whole blood collected at 28 weeks of gestation and following delivery and MeHg in maternal hair obtained at delivery. There were 230 births with complete data on birth weight and covariates. Multiple linear regression models controlled for infant sex, gestational age, maternal age, smoking during pregnancy, intrapartum weight gain, prepregnancy body mass index, maternal socioeconomic status, parity, gestational diabetes, and alcohol use during pregnancy.

RESULTS

The average birth weight was 3252 g (range 1654-4450) and the average gestational age was 39 weeks (range 34-41). Prenatal MeHg exposure and maternal LCPUFA status were not associated with birth weight. Infant sex and length of gestation were the only predictors, with male sex and increased gestational age consistently associated with greater birth weight.

CONCLUSIONS

These findings do not support a relationship between prenatal exposure to LCPUFA and/or MeHg from fish consumption and birth weight.

Transgenic increase in N-3/n-6 Fatty Acid ratio reduces maternal obesity-associated inflammation and limits adverse developmental programming in mice

Maternal and pediatric obesity has risen dramatically over recent years, and is a known predictor of adverse long-term metabolic outcomes in offspring. However, which particular aspects of obese pregnancy promote such outcomes is less clear. While maternal obesity increases both maternal and placental inflammation, it is still unknown whether this is a dominant mechanism in fetal metabolic programming. In this study, we utilized the Fat-1 transgenic mouse to test whether increasing the maternal n-3/n-6 tissue fatty acid ratio could reduce the consequences of maternal obesity-associated inflammation and thereby mitigate downstream developmental programming. Eight-week-old WT or hemizygous Fat-1 C57BL/6J female mice were placed on a high-fat diet (HFD) or control diet (CD) for 8 weeks prior to mating with WT chow-fed males. Only WT offspring from Fat-1 mothers were analyzed. WT-HFD mothers demonstrated increased markers of infiltrating adipose tissue macrophages (P<0.02), and a striking increase in 12 serum pro-inflammatory cytokines (P<0.05), while Fat1-HFD mothers remained similar to WT-CD mothers, despite equal weight gain. E18.5 Fetuses from WT-HFD mothers had larger placentas (P<0.02), as well as increased placenta and fetal liver TG deposition (P<0.01 and P<0.02, respectively) and increased placental LPL TG-hydrolase activity (P<0.02), which correlated with degree of maternal insulin resistance (r = 0.59, P<0.02). The placentas and fetal livers from Fat1-HFD mothers were protected from this excess placental growth and fetal-placental lipid deposition. Importantly, maternal protection from excess inflammation corresponded with improved metabolic outcomes in adult WT offspring. While the offspring from WT-HFD mothers weaned onto CD demonstrated increased weight gain (P<0.05), body and liver fat (P<0.05 and P<0.001, respectively), and whole body insulin resistance (P<0.05), these were prevented in WT offspring from Fat1-HFD mothers. Our results suggest that reducing excess maternal inflammation may be a promising target for preventing adverse fetal metabolic outcomes in pregnancies complicated by maternal obesity.

Supplementation with the omega-3 docosahexaenoic acid: influence on the lipid composition and fatty acid profile of human milk

OBJECTIVE: This study assessed the impact of supplementing the diet of women during pregnancy and lactation with fish oil containing the omega-3 fatty acid docosahexaenoic acid, and its influence on the composition of human milk. METHODS: The sample comprised 60 women aged 18 to 38 years with appropriate dietary pattern, all of them healthy and nonsmokers. The intervention consisted of a daily supplementation with fish oil capsules that corresponded to a daily intake of 315mg of docosahexaenoic acid and 80mg of eicosapentaenoic acid during the third trimester of pregnancy and the first three months postpartum. The total fat content and fatty acid profile of their milk were determined by creamatocrit and gas chromatography. Descriptive statistics were used for data analysis and the significance level was set at p<0.05. RESULTS: There was no statistical difference between the fat contents of the study (fish oil capsules) and control (capsules containing corn starch as filler) groups. However, the milk of women taking fish oil contained higher docosahexaenoic and eicosapentaenoic acid levels 30 and 60 days after delivery. These results demonstrate that high omega-3 intake can influence its concentration in human milk. CONCLUSIONS: Given the importance of docosahexaenoic acid in the neonatal period, it is appropriate for pregnant and breastfeeding women to supplement on long-chain polyunsaturated fatty acids, which may be done by adding fish oil to the regular diet.