The influence of long chain polyunsaturate supplementation on docosahexaenoic acid and arachidonic acid in baboon neonate central nervous system

High-Fat Diets in Animal Models of Alzheimer's Disease: How Can Eating Too Much Fat Increase Alzheimer's Disease Risk?

High dietary intake of saturated fatty acids is a suspected risk factor for neurodegenerative diseases, including Alzheimer's disease (AD). To decipher the causal link behind these associations, high-fat diets (HFD) have been repeatedly investigated in animal models. Preclinical studies allow full control over dietary composition, avoiding ethical concerns in clinical trials. The goal of the present article is to provide a narrative review of reports on HFD in animal models of AD. Eligibility criteria included mouse models of AD fed a HFD defined as > 35% of fat/weight and western diets containing > 1% cholesterol or > 15% sugar. MEDLINE and Embase databases were searched from 1946 to August 2022, and 32 preclinical studies were included in the review. HFD-induced obesity and metabolic disturbances such as insulin resistance and glucose intolerance have been replicated in most studies, but with methodological variability. Most studies have found an aggravating effect of HFD on brain Aβ pathology, whereas tau pathology has been much less studied, and results are more equivocal. While most reports show HFD-induced impairment on cognitive behavior, confounding factors may blur their interpretation. In summary, despite conflicting results, exposing rodents to diets highly enriched in saturated fat induces not only metabolic defects, but also cognitive impairment often accompanied by aggravated neuropathological markers, most notably Aβ burden. Although there are important variations between methods, particularly the lack of diet characterization, these studies collectively suggest that excessive intake of saturated fat should be avoided in order to lower the incidence of AD.

The imperative of arachidonic acid in early human development

This review is about the role of arachidonic acid (ArA) in foetal and early growth and development. In 1975 and '76, we reported the preferential incorporation of ArA into the developing brain of rat pups, its conservation as a principal component in the brains of 32 mammalian species and the high proportion delivered by the human placenta for foetal nutrition, compared to its parent linoleic acid (LA). ArA is quantitatively the principal acyl component of membrane lipids from foetal red cells, mononuclear cells, astrocytes, endothelium, and placenta. Functionally, we present evidence that ArA, but not DHA, relaxes the foetal mesenteric arteries. The placenta biomagnifies ArA, doubling the proportion of the maternal level in cord blood. The proportions of ArA and its allies (di-homo-gamma-linolenic acid (DGLA), adrenic acid and ω6 docosapentaenoic acid) are similar or higher than the total of ω3 fatty acids in human milk, maintaining the abundant supply to the developing infant. Despite the evidence of the importance of ArA, the European Food Standard Agency, in 2014 rejected the joint FAO and WHO recommendation on the inclusion of ArA in infant formula, although they recommended DHA. The almost universal dominance of ArA in the membrane phosphoglycerides during human organogenesis and prenatal growth suggests that the importance of ArA and its allies in reproductive biology needs to be re-evaluated urgently.

The contributions of parental lactation on offspring development: It's not udder nonsense!

The Developmental Origins of Health and Disease (DOHaD) hypothesis describes how maternal stress exposures experienced during critical periods of perinatal life are linked to altered developmental trajectories in offspring. Perinatal stress also induces changes in lactogenesis, milk volume, maternal care, and the nutritive and non-nutritive components of milk, affecting short and long-term developmental outcomes in offspring. For instance, selective early life stressors shape the contents of milk, including macro/micronutrients, immune components, microbiota, enzymes, hormones, milk-derived extracellular vesicles, and milk microRNAs. In this review, we highlight the contributions of parental lactation to offspring development by examining changes in the composition of breast milk in response to three well-characterized maternal stressors: nutritive stress, immune stress, and psychological stress. We discuss recent findings in human, animal, and in vitro models, their clinical relevance, study limitations, and potential therapeutic significance to improving human health and infant survival. We also discuss the benefits of enrichment methods and support tools that can be used to improve milk quality and volume as well as related developmental outcomes in offspring. Lastly, we use evidence-based primary literature to convey that even though select maternal stressors may modulate lactation biology (by influencing milk composition) depending on the severity and length of exposure, exclusive and/or prolonged milk feeding may attenuate the negative in utero effects of early life stressors and promote healthy developmental trajectories. Overall, scientific evidence supports lactation to be protective against nutritive and immune stressors, but the benefits of lactation in response to psychological stressors need further investigation.

Effect of arachidonic and docosahexaenoic acid supplementation on respiratory outcomes and neonatal morbidities in preterm infants

BACKGROUND & AIMS

Studies have suggested that supplementation with docosahexaenoic acid (DHA) to preterm infants might be associated with an increased risk of bronchopulmonary dysplasia (BPD). Our aim was to investigate the effect of enteral supplementation with arachidonic acid (ARA) and DHA on short-term respiratory outcomes and neonatal morbidities in very preterm infants.

METHODS

This is a secondary analysis of data from the ImNuT (Immature, Nutrition Therapy) study, a randomized double blind clinical trial. Infants with gestational age less than 29 weeks were randomized to receive a daily enteral supplement with ARA 100 mg/kg and DHA 50 mg/kg (intervention) or medium chain triglycerides (MCT) oil (control), from second day of life to 36 weeks postmenstrual age. Study outcomes included duration of respiratory support, incidence of BPD and other major morbidities associated with preterm birth.

RESULTS

120 infants with mean (SD) gestational age 26.4 (1.7) weeks were randomized and allocated to either the intervention or control group. Supplementation with ARA and DHA led to a significant reduction in number of days with respiratory support (mean (95% CI) 63.4 (56.6-71.3) vs 80.6 (72.4-88.8); p = 0.03) and a lower oxygen demand (FiO₂) (mean (95% CI) 0.26 (0.25-0.28) vs 0.29 (0.27-0.30); p = 0.03) compared to control treatment. There were no clinically important differences in incidence of BPD and other major morbidities between the treatment groups.

CONCLUSIONS

Supplementation with ARA and DHA to preterm infants was safe and might have a beneficial effect on respiratory outcomes.

CLINICAL TRIAL REGISTRATION

The trial has been registered in www.

CLINICALTRIALS

gov, ID: NCT03555019.

Quantitative and carbon isotope ratio analysis of fatty acids isolated from human brain hemispheres

Our knowledge surrounding the overall fatty acid profile of the adult human brain has been largely limited to extrapolations from brain regions in which the distribution of fatty acids varies. This is especially problematic when modeling brain fatty acid metabolism, therefore, an updated estimate of whole-brain fatty acid concentration is necessitated. Here, we sought to conduct a comprehensive quantitative analysis of fatty acids from entire well-characterized human brain hemispheres (n = 6) provided by the Douglas-Bell Canada Brain Bank. Additionally, exploratory natural abundance carbon isotope ratio (CIR; δ¹³ C, ¹³ C/¹² C) analysis was performed to assess the origin of brain fatty acids. Brain fatty acid methyl esters (FAMEs) were quantified by gas chromatography (GC)-flame ionization detection and minor n-6 and n-3 polyunsaturated fatty acid pentafluorobenzyl esters by GC-mass spectrometry. Carbon isotope ratio values of identifiable FAMEs were measured by GC-combustion-isotope ratio mass spectrometry. Overall, the most abundant fatty acid in the human brain was oleic acid, followed by stearic acid (STA), palmitic acid (PAM), docosahexaenoic acid (DHA), and arachidonic acid (ARA). Interestingly, cholesterol as well as saturates including PAM and STA were most enriched in ¹³ C, while PUFAs including DHA and ARA were most depleted in ¹³ C. These findings suggest a contribution of endogenous synthesis utilizing dietary sugar substrates rich in ¹³ C, and a combination of marine, animal, and terrestrial PUFA sources more depleted in ¹³ C, respectively. These results provide novel insights on cerebral fatty acid origin and concentration, the latter serving as a valuable resource for future modeling of fatty acid metabolism in the human brain.

What Is the Evidence for Dietary-Induced DHA Deficiency in Human Brains?

Docosahexaenoic acid (DHA) is a major constituent of neural and visual membranes and is required for optimal neural and visual function. DHA is derived from food or by endogenous synthesis from α-linolenic acid (ALA), an essential fatty acid. Low blood levels of DHA in some westernised populations have led to speculations that child development disorders and various neurological conditions are associated with sub-optimal neural DHA levels, a proposition which has been supported by the supplement industry. This review searched for evidence of deficiency of DHA in human populations, based on elevated levels of the biochemical marker of n-3 deficiency, docosapentaenoic acid (22:5n-6). Three scenarios/situations were identified for the insufficient supply of DHA, namely in the brain of new-born infants fed with high-linoleic acid (LA), low-ALA formulas, in cord blood of women at birth who were vegetarians and in the milk of women from North Sudan. Twenty post-mortem brain studies from the developed world from adults with various neurological disorders revealed no evidence of raised levels of 22:5n-6, even in the samples with reduced DHA levels compared with control subjects. Human populations most likely at risk of n-3 deficiency are new-born and weanling infants, children and adolescents in areas of dryland agriculture, in famines, or are refugees, however, these populations have rarely been studied. This is an important topic for future research.

Dietary Fatty Acid Composition Impacts the Fatty Acid Profiles of Different Regions of the Bovine Brain

Fatty acid composition across functional brain regions was determined in bovine brains collected from cattle that were provided supplements of calcium salts containing either palm or fish oil. The Angus cattle were divided into two groups, with one group offered the supplement of calcium salts of palm oil and the other offered the calcium salts of fish oil (n = 5 females and n = 5 males/supplement) for 220 days. These supplements to the basal forage diet were provided ad libitum as a suspension in dried molasses. The fish oil exclusively provided eicosapentaenoic acid (EPA, C20:5 n-3) and docosahexaenoic acid (DHA, C22:6 n-3). The functional regions were dissected from the entire brains following commercial harvest. While the cattle provided diets supplemented with the calcium salts of palm oil had increased (p < 0.01) liver concentrations of C18:1 n-9, C18:2 n-6, and arachidonic acid, the fish-oil-supplemented cattle had greater (p < 0.01) concentrations of liver EPA, DHA, and C18:3 n-3. In the brain, DHA was the most abundant polyunsaturated fatty acid. In the amygdala, pons, frontal lobe, internal capsule, and sensory cortex, DHA concentrations were greater (p < 0.05) in the brains of the cattle fed fish oil. Differences among the supplements were small, indicating that brain DHA content is resistant to dietary change. Arachidonic acid and C22:4 n-6 concentrations were greater across the regions for the palm-oil-supplemented cattle. EPA and C22:5 n-3 concentrations were low, but they were greater across the regions for the cattle fed fish oil. The effects of sex were inconsistent. The fatty acid profiles of the brain regions differed by diet, but they were similar to the contents reported for other species.

Reverting to a healthy diet during lactation normalizes maternal milk lipid content of diet-induced obese rats and prevents early alterations in the plasma lipidome of the offspring

Scope

This study aims to assess in rats whether normalizing maternal diet during lactation prevents the harmful effects of western diet (WD) consumption during the whole perinatal period on the lipidomic profile in maternal milk and offspring plasma.

Methods and Results

Control dams (CON‐dams), fed with standard diet (SD); WD‐dams, fed with WD prior and during gestation and lactation; and reversion dams (REV‐dams), fed as WD‐dams but moved to SD during lactation are followed. Lipidomic analysis is performed in milk and plasma samples from pups. Milk of WD‐dams presents a different triacylglycerol composition and free fatty acid (FA) profile compared to CON‐dams, including an increased ratio of pro‐inflammatory to anti‐inflammatory long‐chain polyunsaturated FA. Such alterations, which are also present in the plasma of their offspring, are widely reversed in the milk of REV‐dams and the plasma of their pups. This is related with the recovery of control adiponectin expression levels in the mammary gland, and the presence of decreased expression of pro‐inflammatory factors.

Conclusion

Implementing a healthy diet during lactation prevents early alterations in the plasma lipidome of pups associated to the maternal intake of an obesogenic diet, which may be related to the normalization of milk lipid content and the inflammatory state in the mammary gland.

Roles of the Unsaturated Fatty Acid Docosahexaenoic Acid in the Central Nervous System: Molecular and Cellular Insights

Fatty acids (FAs) are essential components of the central nervous system (CNS), where they exert multiple roles in health and disease. Among the FAs, docosahexaenoic acid (DHA) has been widely recognized as a key molecule for neuronal function and cell signaling. Despite its relevance, the molecular pathways underlying the beneficial effects of DHA on the cells of the CNS are still unclear. Here, we summarize and discuss the molecular mechanisms underlying the actions of DHA in neural cells with a special focus on processes of survival, morphological development, and synaptic maturation. In addition, we examine the evidence supporting a potential therapeutic role of DHA against CNS tumor diseases and tumorigenesis. The current results suggest that DHA exerts its actions on neural cells mainly through the modulation of signaling cascades involving the activation of diverse types of receptors. In addition, we found evidence connecting brain DHA and ω-3 PUFA levels with CNS diseases, such as depression, autism spectrum disorders, obesity, and neurodegenerative diseases. In the context of cancer, the existing data have shown that DHA exerts positive actions as a coadjuvant in antitumoral therapy. Although many questions in the field remain only partially resolved, we hope that future research may soon define specific pathways and receptor systems involved in the beneficial effects of DHA in cells of the CNS, opening new avenues for innovative therapeutic strategies for CNS diseases.

Neurodevelopment, nutrition and genetics. A contemporary retrospective on neurocognitive health on the occasion of the 100th anniversary of the National Institute of Nutrition, Hyderabad, India

In celebration of the centenary of the National Institute of Nutrition (NIN), Hyderabad, India (1918-2018), a symposium highlighted the progress in nutrition knowledge made over the century, as well as major gaps in implementation of that knowledge. Brain famine caused by a shortage of nutrients required for perinatal brain development has unfortunately become a global reality, even as protein-calorie famine was largely averted by the development of high yield crops. While malnutrition remains widespread, the neglect of global food policies that support brain development and maintenance are most alarming. Brain disorders now top the list of the global burden of disease, even with obesity rising throughout the world. Neurocognitive health, remarkably, is seldom listed among the non-communicable diseases (NCDs) and is therefore seldom considered as a component of food policy. Most notably, the health of mothers before conception and through pregnancy as mediated by proper nutrition has been neglected by the current focus on early death in non-neurocognitive NCDs, thereby compromising intellectual development of the ensuing generations. Foods with balanced essential fatty acids and ample absorbable micronutrients are plentiful for populations with access to shore-based foods, but deficient only a few kilometres away from the sea. Sustained access to brain supportive foods is a priority for India and throughout the world to enable each child to develop to their intellectual potential, and support a prosperous, just, and peaceful world. Nutrition education and food policy should place the nutritional requirements for the brain on top of the list of priorities.

Docosahexaenoic Acid Is Naturally Concentrated at the sn-2 Position in Triacylglycerols of the Australian Thraustochytrid Aurantiochytrium sp. Strain TC 20

The Labyrinthulomycetes or Labyrinthulea are a class of protists that produce a network of filaments that enable the cells to glide along and absorb nutrients. One of the main two Labyrinthulea groups is the thraustochytrids, which are becoming an increasingly recognised and commercially used alternate source of long-chain (LC, ≥C₂₀) omega-3 containing oils. This study demonstrates, to our knowledge for the first time, the regiospecificity of the triacylglycerol (TAG) fraction derived from Australian thraustochytrid Aurantiochytrium sp. strain TC 20 obtained using ¹³C nuclear magnetic resonance spectroscopy (¹³C NMR) analysis. The DHA present in the TC 20 TAG fraction was determined to be concentrated in the sn-2 position, with TAG (16:0/22:6/16:0) identified as the main species present. The sn-2 preference is similar to that found in salmon and tuna oil, and differs to seal oil containing largely sn-1,3 LC-PUFA. A higher concentration of sn-2 DHA occurred in the thraustochytrid TC 20 oil compared to that of tuna oil.

Can Natural Products Exert Neuroprotection without Crossing the Blood-Brain Barrier?

The scope of evidence on the neuroprotective impact of natural products has been greatly extended in recent years. However, a key question that remains to be answered is whether natural products act directly on targets located in the central nervous system (CNS), or whether they act indirectly through other mechanisms in the periphery. While molecules utilized for brain diseases are typically bestowed with a capacity to cross the blood–brain barrier, it has been recently uncovered that peripheral metabolism impacts brain functions, including cognition. The gut–microbiota–brain axis is receiving increasing attention as another indirect pathway for orally administered compounds to act on the CNS. In this review, we will briefly explore these possibilities focusing on two classes of natural products: omega-3 polyunsaturated fatty acids (n-3 PUFAs) from marine sources and polyphenols from plants. The former will be used as an example of a natural product with relatively high brain bioavailability but with tightly regulated transport and metabolism, and the latter as an example of natural compounds with low brain bioavailability, yet with a growing amount of preclinical and clinical evidence of efficacy. In conclusion, it is proposed that bioavailability data should be sought early in the development of natural products to help identifying relevant mechanisms and potential impact on prevalent CNS disorders, such as Alzheimer’s disease.

Omega-3 fatty acids accelerate fledging in an avian marine predator: a potential role of cognition

Consuming omega-3 fatty acids (n-3 LCPUFAs) during development improves cognition in mammals, but the effect remains untested in other taxa. In aquatic ecosystems, n-3 LCPUFAs are produced by phytoplankton and bioaccumulate in the food web. Alarmingly, the warming and acidification of aquatic systems caused by climate change impair n-3 LCPUFA production, with an anticipated decrease of 80% by the year 2100. We tested whether n-3 LCPUFA consumption affects the physiology, morphology, behaviour and cognition of the chicks of a top marine predator, the ring-billed gull. Using a colony with little access to n-3 LCPUFAs, we supplemented siblings from 22 fenced nests with contrasting treatments from hatching until fledging; one sibling received n-3 LCPUFA-rich fish oil and the other, a control sucrose solution without n-3 LCPUFAs. Halfway through the nestling period, half the chicks receiving fish oil were switched to the sucrose solution to test whether n-3 LCPUFA intake remains crucial past the main growth phase (chronic versus transient treatments). Upon fledging, n-3 LCPUFAs were elevated in the blood and brains of chicks receiving the chronic treatment, but were comparable to control levels among those receiving the transient treatment. Across the entire sample, chicks with elevated n-3 LCPUFAs in their tissues fledged earlier despite their morphology and activity levels being unrelated to fledging age. Fledging required chicks to escape fences encircling their nest. We therefore interpret fledging age as a possible indicator of cognition, with chicks with improved cognition fledging earlier. These results provide insight into whether declining dietary n-3 LCPUFAs will compromise top predators' problem-solving skills, and thus their ability to survive in a rapidly changing world.

Inflammation and JNK's Role in Niacin-GPR109A Diminished Flushed Effect in Microglial and Neuronal Cells With Relevance to Schizophrenia

Schizophrenia is a neuropsychiatric illness with no single definitive aetiology, making its treatment difficult. Antipsychotics are not fully effective because they treat psychosis rather than the cognitive or negative symptoms. Antipsychotics fail to alleviate symptoms when patients enter the chronic stage of illness. Topical application of niacin showed diminished skin flush in the majority of patients with schizophrenia compared to the general population who showed flushing. The niacin skin flush test is useful for identifying patients with schizophrenia at their ultra-high-risk stage, and understanding this pathology may introduce an effective treatment. This review aims to understand the pathology behind the diminished skin flush response, while linking it back to neurons and microglia. First, it suggests that there are altered proteins in the GPR109A-COX-prostaglandin pathway, inflammatory imbalance, and kinase signalling pathway, c-Jun N-terminal kinase (JNK), which are associated with diminished flush. Second, genes from the GPR109A-COX-prostaglandin pathway were matched against the 128-loci genome wide association study (GWAS) for schizophrenia using GeneCards, suggesting that G-coupled receptor-109A (GPR109A) may have a genetic mutation, resulting in diminished flush. This review also suggests that there may be increased pro-inflammatory mediators in the GPR109A-COX-prostaglandin pathway, which contributes to the diminished flush pathology. Increased levels of pro-inflammatory markers may induce microglial-activated neuronal death. Lastly, this review explores the role of JNK on pro-inflammatory mediators, proteins in the GPR109A-COX-prostaglandin pathway, microglial activation, and neuronal death. Inhibiting JNK may reverse the changes observed in the diminished flush response, which might make it a good therapeutic target.

Polyunsaturated fatty acid biosynthesis pathway and genetics. implications for interindividual variability in prothrombotic, inflammatory conditions such as COVID-19✰,✰✰,★,★★

COVID-19 symptoms vary from silence to rapid death, the latter mediated by both a cytokine storm and a thrombotic storm. SARS-CoV (2003) induces Cox-2, catalyzing the synthesis, from highly unsaturated fatty acids (HUFA), of eicosanoids and docosanoids that mediate both inflammation and thrombosis. HUFA balance between arachidonic acid (AA) and other HUFA is a likely determinant of net signaling to induce a healthy or runaway physiological response. AA levels are determined by a non-protein coding regulatory polymorphisms that mostly affect the expression of FADS1, located in the FADS gene cluster on chromosome 11. Major and minor haplotypes in Europeans, and a specific functional insertion-deletion (Indel), rs66698963, consistently show major differences in circulating AA (>50%) and in the balance between AA and other HUFA (47-84%) in free living humans; the indel is evolutionarily selective, probably based on diet. The pattern of fatty acid responses is fully consistent with specific genetic modulation of desaturation at the FADS1-mediated 20:3→20:4 step. Well established principles of net tissue HUFA levels indicate that the high linoleic acid and low alpha-linoleic acid in populations drive the net balance of HUFA for any individual. We predict that fast desaturators (insertion allele at rs66698963; major haplotype in Europeans) are predisposed to higher risk and pathological responses to SARS-CoV-2 could be reduced with high dose omega-3 HUFA.

Impact of Arachidonic and Docosahexaenoic Acid Supplementation on Neural and Immune Development in the Young Pig

Background: Human milk contains both arachidonic acid (ARA) and docosahexaenoic acid (DHA). Supplementation of infant formula with ARA and DHA results in fatty acid (FA) profiles, neurodevelopmental outcomes, and immune responses in formula-fed infants that are more like those observed in breastfed infants. Consequently, ARA and DHA have been historically added together to infant formula. This study investigated the impact of ARA or DHA supplementation alone or in combination on tissue FA incorporation, immune responses, and neurodevelopment in the young pig.

Methods: Male pigs (N = 48 total) received one of four dietary treatments from postnatal day (PND) 2–30. Treatments targeted the following ARA/DHA levels (% of total FA): CON (0.00/0.00), ARA (0.80/0.00), DHA (0.00/0.80), and ARA+DHA (0.80/0.80). Plasma, red blood cells (RBC), and prefrontal cortex (PFC) were collected for FA analysis. Blood was collected for T cell immunophenotyping and to quantify a panel of immune outcomes. Myelin thickness in the corpus callosum was measured by transmission electron microscopy and pig movement was measured by actigraphy.

Results: There were no differences in formula intake or growth between dietary groups. DHA supplementation increased brain DHA, but decreased ARA, compared with all other groups. ARA supplementation increased brain ARA compared with all other groups but did not affect brain DHA. Combined supplementation increased brain DHA levels but did not affect brain ARA levels compared with the control. Pigs fed ARA or ARA+DHA exhibited more activity than those fed CON or DHA. Diet-dependent differences in activity suggested pigs fed ARA had the lowest percent time asleep, while those fed DHA had the highest. No differences were observed for immune or myelination outcomes.

Conclusion: Supplementation with ARA and DHA did not differentially affect immune responses, but ARA levels in RBC and PFC were reduced when DHA was provided without ARA. Supplementation of either ARA or DHA alone induced differences in time spent asleep, and ARA inclusion increased general activity. Therefore, the current data support the combined supplementation with both ARA and DHA in infant formula and raise questions regarding the safety and nutritional suitability of ARA or DHA supplementation individually.

Relationship between whole blood omega-3 fatty acid levels and dorsal cingulate gray matter volume: Sex differences and implications for impulse control

During adolescence, the prefrontal cortex (PFC) undergoes substantial structural development, including cortical thinning, a process associated with improvements in behavioral control. The cingulate cortex is among the regions recruited in response inhibition and mounting evidence suggests cingulate function may be sensitive to availability of an essential dietary nutrient, omega-3 fatty acids (N3; i.e. EPA + DHA). Our primary aim was to investigate the relationship between a biomarker of omega-3 fatty acids -- percent of whole blood fatty acids as EPA + DHA (N3 Index) -- and cingulate morphology, in typically developing adolescent males (n = 29) and females (n = 33). Voxel-based morphometry (VBM) was used to quantify gray matter volume (GMV) in the dorsal region of the cingulate (dCC). Impulse control was assessed via caregiver report (BRIEF) and Go/No-Go task performance. We predicted that greater N3 Index in adolescents would be associated with less dCC GMV and better impulse control. Results revealed that N3 Index was inversely related to GMV in males, but not in females. Furthermore, males with less right dCC GMV exhibited better caregiver-rated impulse control. A simple mediation model revealed that, in males, N3 Index may indirectly impact impulse control through its association with right dCC GMV. Findings suggest a sex-specific link between levels of N3 and dCC structural development, with adolescent males more impacted by lower N3 levels than females. Identifying factors such as omega-3 fatty acid levels, which may modulate the neurodevelopment of response inhibition, is critical for understanding typical and atypical developmental trajectories associated with this core executive function.

Loss of RAR-related orphan receptor alpha (RORα) selectively lowers docosahexaenoic acid in developing cerebellum

Deficiency in retinoid acid receptor-related orphan receptor alpha (RORα) of staggerer mice results in extensive granule and Purkinje cell loss in the cerebellum as well as in learned motor deficits, cognition impairments and perseverative tendencies that are commonly observed in autistic spectrum disorder (ASD). The effects of RORα on brain lipid metabolism associated with cerebellar atrophy remain unexplored. The aim of this study is to examine the effects of RORα deficiency on brain phospholipid fatty acid concentrations and compositions. Staggerer mice (Rora^sg/sg) and wildtype littermates (Rora^+/+) were fed n-3 polyunsaturated fatty acids (PUFA) containing diets ad libitum. At 2 months and 7 or more months old, brain total phospholipid fatty acids were quantified by gas chromatography-flame ionization detection. In the cerebellum, all fatty acid concentrations were reduced in 2 months old mice. Since total fatty acid concentrations were significantly different at 2-month-old, we examined changes in fatty acid composition. The composition of ARA was not significantly different between genotypes; though DHA composition remained significantly lowered. Despite cerebellar atrophy at >7-months-old, cerebellar fatty acid concentrations had recovered comparably to wildtype control. Therefore, RORα may be necessary for fatty acid accretions during neurodevelopment. Specifically, the effects of RORα on PUFA metabolisms are region-specific and age-dependent.

Marine omega-3 (n-3) phospholipids: A comprehensive review of their properties, sources, bioavailability, and relation to brain health

For several decades, there has been considerable interest in marine-derived long chain n-3 fatty acids (n-3 LCPUFAs) due to their outstanding health benefits. n-3 LCPUFAs can be found in nature either in triglycerides (TAGs) or in phospholipid (PL) form. From brain health point of view, PL n-3 is more bioavailable and potent compared to n-3 in TAG form, as only PL n-3 is able to cross the blood-brain barrier and can be involved in brain biochemical reactions. However, PL n-3 has been ignored in the fish oil industry and frequently removed as an impurity during degumming processes. As a result, PL products derived from marine sources are very limited compared to TAG products. Commercially, PLs are being used in pharmaceutical industries as drug carriers, in food manufacturing as emulsifiers and in cosmetic industries as skin care agents, but most of the PLs used in these applications are produced from vegetable sources that contain less (without EPA, DPA, and DHA) or sometimes no n-3 LCPUFAs. This review provides a comprehensive account of the properties, structures, and major sources of marine PLs, and provides focussed discussion of their relationship to brain health. Epidemiological, laboratory, and clinical studies on n-3 LCPUFAs enriched PLs using different model systems in relation to brain and mental health that have been published over the past few years are discussed in detail.

Effects of maternal protein restriction during pregnancy and lactation on milk composition and offspring development

Before weaning, breast milk is the physiological form of neonatal nutrition, providing pups with all nutrient requirements. Maternal low-protein diet (LPD) during pregnancy and lactation induces adverse changes in key maternal organs, which have negative effects on pup development. We studied the effects of maternal LPD on liver weight, mammary gland (MG) cell differentiation, milk composition and production and pup development throughout lactation. We fed rats with control (C) or LPD (R) during pregnancy and lactation. At 7 d early, 14 d mid and 21 d late lactation stages, maternal biochemical parameters, body, liver and MG weights were analysed. MG cell differentiation was analysed by haematoxylin and eosin staining; milk nutrient composition and production were studied; pup body, liver and brain weights, hippocampal arachidonic acid (AA) and DHA were quantified. Results showed lower body and liver weights, minor MG cell differentiation and lower serum insulin and TAG in R compared with C. R milk contained less protein and higher AA at early and mid stages compared with C. R pup milk and fat intake were lower at all stages. R protein intake at early and mid stages and DHA intake at mid and late stages were lower compared with C. In R pups, lower body, liver and brain weights were associated with decreased hippocampal AA and DHA. We conclude that maternal LPD impairs liver and MG function and induces significant changes in maternal milk composition, pup milk intake and organ development.

Association between Breastmilk LC PUFA, Carotenoids and Psychomotor Development of Exclusively Breastfed Infants

The first months of infant life are crucial for proper neurodevelopment, which may be influenced by several factors, including nutrition and nutrients (e.g., long-chain polyunsaturated fatty acids (LC PUFA) and carotenoids) of which the concentration in breastmilk is diet-dependent. This study analysed the relationship between the average concentrations of selected LC PUFA and carotenoids in breastmilk samples from the first and third months of lactation and the psychomotor development of exclusively breastfed infants at the sixth month of life. Infant psychomotor development was assessed using the Children Development Scale (DSR). The average age of infants during the assessment was 6.6 ± 0.2 months and 30.9 ± 3.8 years for mothers (n = 39 mother⁻infant pairs). The average concentration of docosahexaenoic acid (DHA) was 0.50% of fatty acids. The average concentration of carotenoids was 33.3 nmol/L for β-carotene, 121 nmol/L for lycopene and 33.3 nmol/L for lutein + zeaxanthin. The total results of the Performance scale and Motor subscale were 39 centiles and 4.1 points, respectively. Adjusted multivariate regression models revealed associations between breastmilk DHA and motor development (β = 0.275; p ≤ 0.05), α-linolenic acid (ALA; β = 0.432; p ≤ 0.05), n-3 LC PUFA (β = 0.423; p ≤ 0.05) and β-carotene (β = 0.359; p ≤ 0.05). In addition, an association between the Perception subscale and DHA was observed (β = 0.316; p ≤ 0.05; model 2). There were no significant associations between the overall Performance scale scores. Due to the positive association between concentrations of n-3 LC PUFA (ALA and DHA) and β-carotene in breastmilk and infant motor development, it is important to provide these nutrients with breastmilk. According to the diet-dependent concentration of these compounds in breastmilk, breastfeeding mothers should have a diet abundant in dietary sources of these nutrients, e.g., fish, nuts, seeds, vegetable oils, vegetables and fruits.

Dietary pattern regulates fatty acid desaturase 1 gene expression in Indian pregnant women to spare overall long chain polyunsaturated fatty acids levels

The aim of this study was to determine if the dietary pattern of pregnant women has any compensatory effect on the fatty acid desaturase (FADS) gene expression, thus enhancing the conversion of precursors to long chain polyunsaturated fatty acids (LCPUFA) to spare the overall LCPUFA levels. The dietary intake of plant-based precursor polyunsaturated fatty acids (PUFA) influences circulating levels of LCPUFA. We hypothesized that low LCPUFA diets during pregnancy would compensate by higher expression of FADS genes to enhance the conversion of precursors to LCPUFA to spare the overall LCPUFA levels. Seventy-five pregnant women were enrolled during the last trimester of pregnancy based on the eligibility and exclusion criteria. Maternal LCPUFA in plasma, expression of FADS1 and FADS2 genes, FADS2 Indel genotype status and neonate birth weight were studied.In the vegetarian group (n = 25), plasma α-linolenic acid (ALA) but not linoleic acid (LA) was significantly lower (p < 0.05) than the non-vegetarian group (n = 50). No significant differences were found for arachidonic acid (AA) or docosahexaenoic acid (DHA) levels. FADS1 expression was significantly higher in the vegetarian group compared to the non-vegetarian group. There was no significant difference in the birth weight of the neonates between two groups. No significant correlation was observed between FADS2 Indel genotype and birth weight. Our small sample size study demonstrated an increase FADS1expression during pregnancy in vegetarian pregnant women that may have contributed to the maintenance of AA, eicosapentaenoic acid and DHA levels thereby ensuring that the overall LCPUFA levels of the neonate is not compromised.

Acyl-CoA synthetase 6 enriches the neuroprotective omega-3 fatty acid DHA in the brain

Docosahexaenoic acid (DHA) is an omega-3 fatty acid that is highly abundant in the brain and confers protection against numerous neurological diseases, yet the fundamental mechanisms regulating the enrichment of DHA in the brain remain unknown. Here, we have discovered that a member of the long-chain acyl-CoA synthetase family, Acsl6, is required for the enrichment of DHA in the brain by generating an Acsl6-deficient mouse (Acsl6^-/-). Acsl6 is highly enriched in the brain and lipid profiling of Acsl6^-/- tissues reveals consistent reductions in DHA-containing lipids in tissues highly abundant with Acsl6. Acsl6^-/- mice demonstrate motor impairments, altered glutamate metabolism, and increased astrogliosis and microglia activation. In response to a neuroinflammatory lipopolysaccharide injection, Acsl6^-/- brains show similar increases in molecular and pathological indices of astrogliosis compared with controls. These data demonstrate that Acsl6 is a key mediator of neuroprotective DHA enrichment in the brain.

Effects of soft electrophiles on selenium physiology

This review examines the effects of neurotoxic electrophiles on selenium (Se) metabolism. Selenium-dependent enzymes depend on the unique and elite functions of selenocysteine (Sec), the 21st proteinogenic amino acid, to perform their biochemical roles. Humans possess 25 selenoprotein genes, ~ half of which are enzymes (selenoenzymes) required for preventing, controlling, or reversing oxidative damage, while others participate in regulating calcium metabolism, thyroid hormone status, protein folding, cytoskeletal structure, Sec synthesis and Se transport. While selenoproteins are expressed in tissue dependent distributions and levels in all cells of all vertebrates, they are particularly important in brain development, health, and functions. As the most potent intracellular nucleophile, Sec is subject to binding by mercury (Hg) and other electron poor soft neurotoxic electrophiles. Epidemiological and environmental studies of the effects of exposures to methyl-Hg (CH₃Hg⁺), elemental Hg (Hg°), and/or other metallic/organic neurotoxic soft electrophiles need to consider the concomitant effects of all members of this class of toxicants in relation to the Se status of their study populations. The contributions of individual electrophiles' discrete and cooperative rates of Se sequestration need to be evaluated in relation to tissue Se reserves of the exposed populations to identify sensitive subgroups which may be at accentuated risk due to poor Se status. Additional study is required to examine possibilities of inherited, acquired, or degenerative neurological disorders of Se homeostasis that may influence vulnerability to soft electrophile exposures. Investigations of soft electrophile toxicity will be enhanced by considering the concomitant effects of combined exposures on tissue Se-availability in relation to pathological consequences during fetal development or in relation to etiologies of neurological disorders and neurodegenerative diseases. Since selenoenzymes are molecular "targets" of soft electrophiles, concomitant evaluation of aggregate exposures to these toxicants in relation to dietary Se intakes will assist regulatory agencies in their goals of improving and protecting public health.

Differential Pattern of Phospholipid Profile in the Temporal Cortex from E280A-Familiar and Sporadic Alzheimer's Disease Brains

Lipids are considered important factors in the pathogenesis of Alzheimer's disease (AD). In this study, we realized a comparative analysis of the phospholipid profile and phospholipid composition of the temporal cortex from E280A-familiar AD (FAD), sporadic AD (SAD), and healthy human brains. Findings showed a significant decrease of lysophosphatidylcholine and phosphatidylethanolamine formed by low levels of polyunsaturated fatty acids (20 : 4, 22 : 6) in AD brains. However, phosphatidylethanolamine-ceramide and phosphoglycerol were significantly increased in SAD, conformed by high levels of (18 : 0/18 : 1) and (30/32/36 : 0/1/2), respectively. Together, the findings suggest a deficiency in lysophosphacholine and phosphatidylethanolamine, and alteration in the balance between poly- and unsaturated fatty acids in both types of AD, and a differential pattern of phospholipid profile and fatty acid composition between E280A FAD and SAD human brains.

Maternal fish consumption during pregnancy and smoking behavioural patterns

n-3 Highly unsaturated fatty acids (HUFA), are essential components of neuronal membranes and mediate a range of complex bioactive properties including gene expression, myelination, cell-signalling and dopaminergic function. Deficits in n-3 HUFA have been linked to increased risks for addictive disorders, thus we posited that lower fish consumption would be associated with greater risks for perinatal smoking among 9640 mothers enroled in the Avon Longitudinal Study of Parents and Children. We used univariable and multivariable regression models to examine relationships between self-reported prenatal dietary intakes of n-3 HUFA-rich foods (fish and shellfish) and maternal smoking; outcomes included cessation and the number of cigarettes smoked per d. Both before and during pregnancy, there was consistent evidence (P<0·001) of protective fish intake-smoking associations; relative to mothers reporting no fish consumption, those who reported some fish consumption (<340 g/week) and high fish consumption (340 g+/week) at 32 weeks of gestation showed lower likelihoods of smoking (adjusted P values <0·001). Respective OR for these relationships were 0·87 (95% CI 0·77, 0·97) and 0·73 (95% CI 0·61, 0·86). Although the prevalence of smoking diminished, from a high of 31·6% (pre-pregnancy) to a low of 18·7% (second trimester), the magnitude of fish intake-smoking associations remained stable following adjustment for confounders. These observations suggest that greater fish or n-3 HUFA consumption should be evaluated as an intervention to reduce or prevent smoking in randomised clinical trials.

Synthesis of 2-docosahexaenoylglycerol by enzymatic ethanolysis

Synthesis of 2-docosahexaenoylglycerol with high nutritional value was conducted by enzymatic ethanolysis of algal oil. The effects of lipase type, substrate molar ratio of algal oil to ethanol, reaction time, reaction temperature and lipase load on the content of 2-monoacylglycerols (2-MAGs) in the crude product were investigated. Under the optimal conditions, 27-31% 2-MAGs were obtained in the ethanolysis reaction. Lipozyme 435 exhibited 1,3-specific selectivity and maintained stable operational stability after 7 successive reuse cycles. The enzymatic ethanolysis catalyzed by Lipozyme 435 could both synthesize 2-MAGs and concentrate DHA. Further purification of 2-MAGs was performed with solvent extraction by 85% ethanol aqueous solution and hexane, obtaining 95% 2-MAGs in a yield of 67%. The contents of DHA in 2-MAGs product and 2-MAGs fraction were 74.76% and 75.66%, respectively, which were about 26% higher than that in the algal oil. Therefore, this method is efficient and environmental-friendly for synthesis of 2-docosahexaenoylgylcerol.

Brain docosahexaenoic acid uptake and metabolism

Docosahexaenoic acid (DHA) is the most abundant n-3 polyunsaturated fatty acid in the brain where it serves to regulate several important processes and, in addition, serves as a precursor to bioactive mediators. Given that the capacity of the brain to synthesize DHA locally is appreciably low, the uptake of DHA from circulating lipid pools is essential to maintaining homeostatic levels. Although, several plasma pools have been proposed to supply the brain with DHA, recent evidence suggests non-esterified-DHA and lysophosphatidylcholine-DHA are the primary sources. The uptake of DHA into the brain appears to be regulated by a number of complementary pathways associated with the activation and metabolism of DHA, and may provide mechanisms for enrichment of DHA within the brain. Following entry into the brain, DHA is esterified into and recycled amongst membrane phospholipids contributing the distribution of DHA in brain phospholipids. During neurotransmission and following brain injury, DHA is released from membrane phospholipids and converted to bioactive mediators which regulate signaling pathways important to synaptogenesis, cell survival, and neuroinflammation, and may be relevant to treating neurological diseases. In the present review, we provide a comprehensive overview of brain DHA metabolism, encompassing many of the pathways and key enzymatic regulators governing brain DHA uptake and metabolism. In addition, we focus on the release of non-esterified DHA and subsequent production of bioactive mediators and the evidence of their proposed activity within the brain. We also provide a brief review of the evidence from post-mortem brain analyses investigating DHA levels in the context of neurological disease and mood disorder, highlighting the current disparities within the field.

Impaired prolactin actions mediate altered offspring metabolism induced by maternal high-fat feeding during lactation

Maternal diet during lactation affects offspring metabolic health throughout life. Prolactin (PRL) is present in high quantities in maternal milk; however, the effects of milk PRL on the offspring remain poorly characterized. In this study, we evaluated whether feeding a high-fat diet (HFD) to rats during lactation alters PRL, both in the mother's serum and in milk, and whether this factor contributes to HFD-induced metabolic dysfunction in the offspring. Maternal HFD resulted in decreased PRL levels in milk (but not in serum), reduced mammary gland (MG) PRL receptor expression, and altered MG structure and function. Offspring from HFD-fed dams had increased body weight and adiposity, and developed fatty liver, hyperinsulinemia, and insulin resistance at weaning. Increasing PRL levels in the HFD-fed mothers by subcutaneous osmotic minipumps releasing PRL normalized MG function and PRL levels in milk. Moreover, PRL treatment in HFD-fed mothers, or directly in their pups via oral PRL administration, increased liver STAT5 phosphorylation, reduced visceral adiposity, ameliorated fatty liver, and improved insulin sensitivity in offspring. Our results show that HFD impairs PRL actions during lactation to negatively affect MG physiology and directly impair offspring metabolism.-De los Ríos, E. A., Ruiz-Herrera, X., Tinoco-Pantoja, V., López-Barrera, F., Martínez de la Escalera, G., Clapp, C., Macotela, Y. Impaired prolactin actions mediate altered offspring metabolism induced by maternal high-fat feeding during lactation.

The role of fatty acid desaturase (FADS) genes in oleic acid metabolism: FADS1 Δ7 desaturates 11-20:1 to 7,11-20:2

INTRODUCTION

In mammals, FADS2 catalyzes "front-end" Δ4-, Δ6-, and Δ8-desaturation of fatty acyl chains, whereas FADS1 has Δ5-desaturase activity. Eighteen and 20-carbon precursors to highly unsaturated n-3 and n-6 fatty acids are the usual substrates for FADS1 and FADS2. Our main objective was to characterize the metabolic fate of oleic acid (OA) due to action of FADS gene products.

METHODS

MCF-7 cells were stably transformed with either FADS1 or FADS2 or empty vector. A series of dose-response experiments were conducted with albumin-bound fatty acid substrates (18:1n-9 and 20:1n-9) provided in concentrations up to 100µM. Cells were harvested after 24h, after which FAME were prepared and analyzed by GC-FID and covalent adduct chemical ionization tandem mass spectrometry (CACI-MS/MS).

RESULTS

When stably transformed cells were incubated with 18:1n-9, FADS1 and control cells elongated 18:1n-9 → 20:1n-9 (11-20:1), while FADS2 cells Δ6 desaturated, elongated, and then Δ5 desaturated via FADS1 coded activity leading to Mead acid, 9-18:1 → 6,9-18:2 → 8,11-20:2 (20:2n-9) → 6,8,11-20:3 (20:3n-9). Surprisingly, FADS1 cells Δ7 desaturated 11-20:1 → 7,11-20:2, the latter detected at low levels in control and FADS2 cells. Our results imply three pathways operate on 18:1n-9: 1) 18:1n-9 → 18:2n-9 → 20:2n-9 → 20:3n-9; 2) 18:1n-9 → 20:1n-9 → 20:2n-9 → 20:3n-9 and 3) 18:1n-9 → 20:1n-9 → 7,11-20:2.

CONCLUSION

Alternative pathways for oleic acid metabolism exist depending on FADS2 or FADS1 activities, we present the first evidence of Δ7 desaturation via the FADS1 gene product.

The role of lipids in corneal diseases and dystrophies: a systematic review

Corneal diseases are an extensive cause of blindness worldwide and continue to persist as a challenging public health concern. Recently, various lipid-based therapies have been advocated for the modulation of corneal diseases; however, the number of studies is still very limited. Here we focus on developments and challenges on lipid-based therapies for dry eye disease, diabetic neuropathy, and Fuchs' endothelial corneal dystrophy. All three diseases are highly prevalent conditions and involve corneal stress and inflammation. Lipid-based therapeutics discussed includes cyclooxygenase inhibitors, essential fatty acids, and resolvin analogs. Lipids also show increasing promise as biomarkers of disease and are explored in this review.

Functional analysis of the dehydratase domains of a PUFA synthase from Thraustochytrium in Escherichia coli

Thraustochytrium sp. 26185, a unicellular marine protist, synthesizes docosahexaenoic acid, an omega-3 very long chain polyunsaturated fatty acid (VLC-PUFAs), by a polyunsaturated fatty acid (PUFA) synthase comprising three large subunits with multiple catalytic dehydratase (DH) domains critical for introducing double bonds at the specific position of fatty acids. To investigate functions of these DH domains, one DH domain from subunit-A and two DH domains from subunit-C of the PUFA synthase were dissected and expressed as stand-alone enzymes in Escherichia coli. The results showed that all these DH domains could complement the defective phenotype of a E. coli FabA temperature sensitive mutant, despite they have only modest sequence similarity with FabA, indicating they can function as 3-hydroxyacyl-ACP dehydratase for the biosynthesis of unsaturated fatty acids in E. coli. Site-directed mutagenesis analysis confirmed the authenticity of active site residues in these domains. In addition, overexpression of the three domains in a wild type E. coli strain resulted in the substantial alteration of fatty acid profiles including productions and ratio of unsaturated to saturated fatty acids. A combination of evidences from sequence comparison, functional expression, and mutagenesis analysis suggest that the DH domain from subunit-A is similar to DH domains from polyketide synthases, while the DH domains from subunit-C are more comparable to E. coli FabA in catalytic functions. Successful complementation and functional expression of the embedded DH domains from the PUFA synthase in E. coli is an important step towards for elucidating the molecular mechanism in the biosynthesis of VLC-PUFAs in Thraustochytrium.

Arachidonic Acid Induces ARE/Nrf2-Dependent Heme Oxygenase-1 Transcription in Rat Brain Astrocytes

Arachidonic acid (AA) is a major product of phospholipid hydrolysis catalyzed by phospholipase A₂ during neurodegenerative diseases. AA exerts as a second messenger to regulate various signaling components which may be involved in different pathophysiological processes. Astrocytes are the main types of CNS resident cells which maintain and support the physiological function of brain. AA has been shown to induce ROS generation through activation of NADPH oxidases (Noxs) which may play a key role in the expression of heme oxygenase-1 (HO-1). Therefore, this study was designed to investigate the mechanisms underlying AA-induced HO-1 expression in rat brain astrocytes (RBA-1). We found that AA induced HO-1 protein and mRNA expression and promoter activity in RBA-1, which was mediated through the synthesis of 15-deoxy-Δ12,14-prostaglandin D₂-activated peroxisome proliferator-activated receptor-γ (PPARγ) receptors. This note was confirmed by transfection with PPARγ small interfering RNAs (siRNA) which attenuated the AA-mediated responses. AA-induced HO-1 expression was mediated through Nox/ROS generation, which was inhibited by Nox inhibitors (diphenyleneiodonium and apocynin) and ROS scavengers (N-acetyl cysteine). Moreover, AA-induced HO-1 expression was mediated through phosphorylation of Src, Pyk2, platelet-derived growth factor, PI3K/Akt, and ERK1/2 which were inhibited by the pharmacological inhibitors including PP1, PF431396, AG1296, LY294002, and U0126 or by transfection with respective siRNAs. AA-enhanced Nrf2 expression and HO-1 promoter activity was inhibited by transfection with Nrf2 siRNA or by these pharmacological inhibitors. Furthermore, chromatin immunoprecipitation assay confirmed that Nrf2 and PPARγ were associated with the proximal antioxidant response element (ARE)-binding site on HO-1 promoter, suggesting that Nrf2/PPARγ are key transcription factors modulating HO-1 expression. AA-induced ARE promoter activity was also reduced by these pharmacological inhibitors. These findings suggested that AA increases formation of Nrf2 and PPARγ complex and binding with ARE1 binding site through Src, Pyk2, PI3K/Akt, and ERK1/2, which further induced HO-1 expression in RBA-1 cells.

Prenatal fish oil supplementation and early childhood development in the Upstate KIDS Study

Fish oil contains omega-3 fatty acids, which play a vital role in fetal growth and development. In utero exposure to omega-3 fatty acids is exclusively dependent on maternal nutrition. Previous studies have suggested that prenatal fish oil supplementation has positive impacts on child neurodevelopment later in life. This study examines the associations between fish oil supplementation both before pregnancy and throughout pregnancy and subsequent child development. Mother-child pairs from the Upstate KIDS Study, a birth cohort consisting of children born between 2008 and 2010, were included. Self-reported prenatal fish oil supplementation data were available for 5845 children (3807 singletons and 2038 twins). At multiple time points, from 4 months to 3 years of age, child development was reported by the parents on the Ages and Stages Questionnaire (ASQ). Five developmental domains were assessed: fine motor, gross motor, communication, personal-social functioning and problem solving. Generalized linear mixed models were used to estimate odds ratios (OR) while adjusting for covariates. Primary analyses showed that the risk of failing the ASQ problem-solving domain was significantly lower among children of women who took fish oil before pregnancy (OR 0.40, 95% confidence intervals (CI) 0.18-0.89) and during pregnancy (OR 0.43, 95% CI 0.22-0.83). Gender interaction was not statistically significant, although stratified results indicated stronger associations among girls. Similarly, associations were primarily among singletons. Prenatal fish oil supplementation may be beneficial in regards to neurodevelopment. Specifically, it is associated with a lower risk of failing the problem-solving domain up to 3 years of age.

Ketoacylsynthase Domains of a Polyunsaturated Fatty Acid Synthase in Thraustochytrium sp. Strain ATCC 26185 Can Effectively Function as Stand-Alone Enzymes in Escherichia coli

Thraustochytrium sp. strain ATCC 26185 accumulates a high level of docosahexaenoic acid (DHA), a nutritionally important ω-3 very-long-chain polyunsaturated fatty acid (VLCPUFA) synthesized primarily by polyunsaturated fatty acid (PUFA) synthase, a type I polyketide synthase-like megaenzyme. The PUFA synthase in this species comprises three large subunits, each with multiple catalytic domains. It was hypothesized that among these domains, ketoacylsynthase (KS) domains might be critical for catalyzing the condensation of specific unsaturated acyl-acyl carrier proteins (ACPs) with malonyl-ACP, thereby retaining double bonds in an extended acyl chain. To investigate the functions of these putative KS domains, two segment sequences from subunit A (KS-A) and subunit B (KS-B) of the PUFA synthase were dissected and then expressed as stand-alone enzymes in Escherichia coli The results showed that both KS-A and KS-B domains could complement the defective phenotypes of both E. colifabB and fabF mutants. Overexpression of these domains in wild-type E. coli led to increases in total fatty acid production. KS-B produced a higher ratio of unsaturated fatty acids (UFAs) to saturated fatty acids (SFAs), while KS-A could improve the overall production of fatty acids more effectively, particularly for the production of SFAs, implying that KS-A is more comparable to FabF, while KS-B is more similar to FabB in catalytic functions. Successful complementation and functional expression of the embedded KS domains in E. coli are the first step forward in studying the molecular mechanism of the PUFA synthase for the biosynthesis of VLCPUFAs in ThraustochytriumIMPORTANCE Very-long-chain polyunsaturated fatty acids (VLCPUFAs) are important for human health. They can be biosynthesized in either an aerobic pathway or an anaerobic pathway in nature. However, abundant VLCPUFAs in marine microorganisms are primarily synthesized by polyunsaturated fatty acid (PUFA) synthase, a megaenzyme with multiple subunits, each with multiple catalytic domains. Furthermore, the fundamental mechanism for this enzyme to synthesize these fatty acids still remains unknown. This report started with dissecting the embedded KS domains of the PUFA synthase from marine protist Thraustochytrium sp. strain ATCC 26185 and then expressing them in wild-type E. coli and mutants defective in condensation of acyl-ACP with malonyl-ACP. Successful complementation of the mutants and improved fatty acid production in the overexpression experiments indicate that these KS domains can effectively function as stand-alone enzymes in E. coli This result has paved the way for further studying of molecular mechanisms of the PUFA synthase for the biosynthesis of VLCPUFAs.

Hepatic transcriptome analysis and identification of differentially expressed genes response to dietary oxidized fish oil in loach Misgurnus anguillicaudatus

RNA sequencing and short-read assembly were utilized to produce a transcriptome of livers from loaches (Misgurnus anguillicaudatus) fed with three different diets respectively containing fresh fish oil (FO group), medium oxidized fish oil (MO group) and high oxidized fish oil (HO group). A total of 60,663 unigenes were obtained in this study, with mean length 848.74 bp. 50,814, 49,584 and 49,814 unigenes were respectively obtained from FO, MO and HO groups. There were 2,343 differentially expressed genes between FO and MO, with 855 down- and 1,488 up-regulated genes in the MO group. 2,813 genes were differentially expressed between FO and HO, including 1,256 down- and 1,552 up-regulated genes in the HO group. 2,075 differentially expressed genes were found in the comparison of MO and HO, including 1,074 up- and 1,001 down-regulated genes in the MO group. Some differentially expressed genes, such as fatty acid transport protein (fatp), fatty acid binding protein (fabp), apolipoprotein (apo), peroxisome proliferator activated receptor-gamma (ppar-γ), acetyl-CoA synthetase (acs) and arachidonate 5-lipoxygenase (alox5), were involved in lipid metabolism, suggesting these genes in the loach were responsive to dietary oxidized fish oil. Results of transcriptome profilings here were validated using quantitative real time PCR in fourteen randomly selected unigenes. The present study provides insights into hepatic transcriptome profile of the loach, which is a valuable resource for studies of loach genomics. More importantly, this study identifies some important genes responsible for dietary oxidized fish oil, which will benefit researches of lipid metabolism in fish.

Combined Supplementation of Choline and Docosahexaenoic Acid during Pregnancy Enhances Neurodevelopment of Fetal Hippocampus

Choline is an essential nutrient for humans which plays an important role in structural integrity and signaling functions. Docosahexaenoic acid (DHA) is a polyunsaturated fatty acid, highly enriched in cell membranes of the brain. Dietary intake of choline or DHA alone by pregnant mothers directly affects fetal brain development and function. But no studies show the efficacy of combined supplementation of choline and DHA on fetal neurodevelopment. The aim of the present study was to analyze fetal neurodevelopment on combined supplementation of pregnant dams with choline and DHA. Pregnant dams were divided into five groups: normal control [NC], saline control [SC], choline [C], DHA, and C + DHA. Saline, choline, and DHA were given as supplements to appropriate groups of dams. NC dams were undisturbed during entire gestation. On postnatal day (PND) 40, brains were processed for Cresyl staining. Pups from choline or DHA supplemented group showed significant (p < 0.05) increase in number of neurons in hippocampus when compared to the same in NC and SC groups. Moreover, pups from C + DHA supplemented group showed significantly higher number of neurons (p < 0.001) in hippocampus when compared to the same in NC and SC groups. Thus combined supplementation of choline and DHA during normal pregnancy enhances fetal hippocampal neurodevelopment better than supplementation of choline or DHA alone.

Positive Selection on a Regulatory Insertion-Deletion Polymorphism in FADS2 Influences Apparent Endogenous Synthesis of Arachidonic Acid

Long chain polyunsaturated fatty acids (LCPUFA) are bioactive components of membrane phospholipids and serve as substrates for signaling molecules. LCPUFA can be obtained directly from animal foods or synthesized endogenously from 18 carbon precursors via the FADS2 coded enzyme. Vegans rely almost exclusively on endogenous synthesis to generate LCPUFA and we hypothesized that an adaptive genetic polymorphism would confer advantage. The rs66698963 polymorphism, a 22-bp insertion–deletion within FADS2, is associated with basal FADS1 expression, and coordinated induction of FADS1 and FADS2 in vitro. Here, we determined rs66698963 genotype frequencies from 234 individuals of a primarily vegetarian Indian population and 311 individuals from the US. A much higher I/I genotype frequency was found in Indians (68%) than in the US (18%). Analysis using 1000 Genomes Project data confirmed our observation, revealing a global I/I genotype of 70% in South Asians, 53% in Africans, 29% in East Asians, and 17% in Europeans. Tests based on population divergence, site frequency spectrum, and long-range haplotype consistently point to positive selection encompassing rs66698963 in South Asian, African, and some East Asian populations. Basal plasma phospholipid arachidonic acid (ARA) status was 8% greater in I/I compared with D/D individuals. The biochemical pathway product–precursor difference, ARA minus linoleic acid, was 31% and 13% greater for I/I and I/D compared with D/D, respectively. This study is consistent with previous in vitro data suggesting that the insertion allele enhances n-6 LCPUFA synthesis and may confer an adaptive advantage in South Asians because of the traditional plant-based diet practice.

Fatty acid composition and fatty acid binding protein expression in the postmortem frontal cortex of patients with schizophrenia: A case-control study

BACKGROUND

Abnormal levels of n-3 polyunsaturated fatty acids (PUFAs), particularly docosahexaenoic acid (DHA), have been found in the postmortem frontal cortex, particularly the orbitofrontal cortex, of patients with schizophrenia. Altered mRNA expression of fatty acid binding protein (FABP) 5 and FABP7 has likewise been reported.

METHODS

This study investigated whether PUFAs in the frontal cortex [Brodmann area (BA) 8] and mRNA expression of FABP3, 5, and 7 were different between patients with schizophrenia (n=95) and unaffected controls (n=93).

RESULTS

In contrast to previous studies, no significant differences were found in DHA between the groups. Although arachidonic acid (AA) levels were significantly decreased in the schizophrenia group, no association was found between AA and schizophrenia on logistic regression analysis. Only FABP3 expression was significantly lower in the schizophrenia group than in the control group. Significant inverse associations were seen between only two saturated fatty acids, behenic acid and lignoceric acid, and FABP3 expression.

CONCLUSIONS

We found no evidence that major PUFA levels in BA8 are involved in the etiology of schizophrenia. Although FABP3 expression was not correlated with any of the major PUFAs, it might play a novel role in the pathology of BA8 in a subset of patients with schizophrenia.

Docosahexaenoic Acid and Cognition throughout the Lifespan

Docosahexaenoic acid (DHA) is the predominant omega-3 (n-3) polyunsaturated fatty acid (PUFA) found in the brain and can affect neurological function by modulating signal transduction pathways, neurotransmission, neurogenesis, myelination, membrane receptor function, synaptic plasticity, neuroinflammation, membrane integrity and membrane organization. DHA is rapidly accumulated in the brain during gestation and early infancy, and the availability of DHA via transfer from maternal stores impacts the degree of DHA incorporation into neural tissues. The consumption of DHA leads to many positive physiological and behavioral effects, including those on cognition. Advanced cognitive function is uniquely human, and the optimal development and aging of cognitive abilities has profound impacts on quality of life, productivity, and advancement of society in general. However, the modern diet typically lacks appreciable amounts of DHA. Therefore, in modern populations, maintaining optimal levels of DHA in the brain throughout the lifespan likely requires obtaining preformed DHA via dietary or supplemental sources. In this review, we examine the role of DHA in optimal cognition during development, adulthood, and aging with a focus on human evidence and putative mechanisms of action.

Docosahexaenoic Acid and Cognition throughout the Lifespan

Docosahexaenoic acid (DHA) is the predominant omega-3 (n-3) polyunsaturated fatty acid (PUFA) found in the brain and can affect neurological function by modulating signal transduction pathways, neurotransmission, neurogenesis, myelination, membrane receptor function, synaptic plasticity, neuroinflammation, membrane integrity and membrane organization. DHA is rapidly accumulated in the brain during gestation and early infancy, and the availability of DHA via transfer from maternal stores impacts the degree of DHA incorporation into neural tissues. The consumption of DHA leads to many positive physiological and behavioral effects, including those on cognition. Advanced cognitive function is uniquely human, and the optimal development and aging of cognitive abilities has profound impacts on quality of life, productivity, and advancement of society in general. However, the modern diet typically lacks appreciable amounts of DHA. Therefore, in modern populations, maintaining optimal levels of DHA in the brain throughout the lifespan likely requires obtaining preformed DHA via dietary or supplemental sources. In this review, we examine the role of DHA in optimal cognition during development, adulthood, and aging with a focus on human evidence and putative mechanisms of action.

Alterations in levels and ratios of n-3 and n-6 polyunsaturated fatty acids in the temporal cortex and liver of vervet monkeys from birth to early adulthood

Deficiencies in omega-3 (n-3) long chain polyunsaturated fatty acids (LC-PUFAs) and increases in the ratio of omega-6 (n-6) to n-3 LC-PUFAs in brain tissues and blood components have been associated with psychiatric and developmental disorders. Most studies have focused on n-3 LC-PUFA accumulation in the brain from birth until 2years of age, well before the symptomatic onset of such disorders. The current study addresses changes that occur in childhood and adolescence. Postmortem brain (cortical gray matter, inferior temporal lobe; n=50) and liver (n=60) from vervet monkeys fed a uniform diet from birth through young adulthood were collected from archived tissues. Lipids were extracted and fatty acid levels determined. There was a marked reduction in the ratio of n-6 LC-PUFAs, arachidonic acid (ARA) and adrenic acid (ADR), relative to the n-3 LC-PUFA, docosahexaenoic acid (DHA), in temporal cortex lipids from birth to puberty and then a more gradual decrease though adulthood. This decrease in ratio resulted from a 3-fold accumulation of DHA levels while concentrations of ARA remained constant. Early childhood through adolescence appears to be a critical period for DHA accretion in the cortex of vervet monkeys and may represent a vulnerable stage where lack of dietary n-3 LC-PUFAs impacts development in humans.

Brown but not white adipose cells synthesize omega-3 docosahexaenoic acid in culture

Adipose tissue is a complex endocrine organ which coordinates several crucial biological functions including fatty acid metabolism, glucose metabolism, energy homeostasis, and immune function. Brown adipose tissue (BAT) is most abundant in young infants during the brain growth spurt when demands for omega-3 docosahexaenoic acid (DHA, 22:6n-3) is greatest for brain structure. Our aim was to characterize relative biosynthesis of omega-3 long chain polyunsaturated fatty acids (LCPUFA) from precursors in cultured white (WAT) and brown (BAT) cells and study relevant gene expression. Mouse WAT and BAT cells were grown in regular DMEM media to confluence, and differentiation was induced. At days 0 and 8 cells were treated with albumin bound d5-18:3n-3 (d5-ALA) and analyzed 24h later. d5-ALA increased cellular eicosapentaenoic acid (EPA, 20:5n-3) and docosapentaenoic acid (DPA, 22:5n-3) in undifferentiated BAT cells, whereas differentiated BAT cells accumulated 20:4n-3, EPA and DPA. DHA as a fraction of total omega-3 LCPUFA was greatest in differentiated BAT cells compared to undifferentiated cells. Undifferentiated WAT cells accumulated EPA, whereas differentiated cells accumulated DPA. WAT accumulated trace newly synthesized DHA. Zic1 a classical brown marker and Prdm16 a key driver of brown fat cell fate are expressed only in BAT cells. Ppargc1a is 15 fold higher in differentiated BAT cells. We conclude that in differentiated adipose cells accumulating fat, BAT cells but not WAT cells synthesize DHA, supporting the hypothesis that BAT is a net producer of DHA.

Changes in milk composition in obese rats consuming a high-fat diet

Maternal obesity programmes offspring development. We addressed maternal obesity effects induced by high-fat diets on maternal mammary gland (MG) structure and function and offspring brain, liver and fat outcomes. Mothers were fed control (C, n 5) or obesogenic (MO, n 5) diet from the time they were weaned through pregnancy beginning at 120 d, through lactation. At offspring postnatal day (PND) 20, milk leptin and nutrients were determined. At the end of lactation, maternal liver and MG fatty acid profile were measured. Desaturase (Δ6D and Δ5D) and elongase (ELOVL 5 and ELOVL 2) protein was measured by immunohistochemistry and Western blotting (WB) in the liver and WB in the MG. In mothers, liver, MG and milk fat content were higher in MO than in C. Liver arachidonic acid (AA) and EPA and MG EPA were lower in MO than in C. Liver desaturases were higher in MO. The MG was heavier in MO than in C, with decreased Δ5D expression in MO. Desaturases and elongases were immunolocalised in parenchymal cells of both groups. Milk yield, water, carbohydrate content, EPA and DHA were lower, whereas milk leptin and AA were higher in MO than in C. At PND 21 and 36, brain weight was less and fat depots were greater in MO offspring than in C. MO decreased male absolute brain weight but not female absolute brain weight. In conclusion, maternal obesity induced by an obesogenic diet negatively affects maternal liver and MG function with the production of significant changes in milk composition. Maternal obesity adversely affects offspring metabolism and development.

N-docosahexaenoylethanolamine regulates Hedgehog signaling and promotes growth of cortical axons

Axonogenesis, a process for the establishment of neuron connectivity, is central to brain function. The role of metabolites derived from docosahexaenoic acid (DHA, 22:6n-3) that is specifically enriched in the brain, has not been addressed in axon development. In this study, we tested if synaptamide (N-docosahexaenoylethanolamine), an endogenous metabolite of DHA, affects axon growth in cultured cortical neurons. We found that synaptamide increased the average axon length, inhibited GLI family zinc finger 1 (GLI1) transcription and sonic hedgehog (Shh) target gene expression while inducing cAMP elevation. Similar effects were produced by cyclopamine, a regulator of the Shh pathway. Conversely, Shh antagonized elevation of cAMP and blocked synaptamide-mediated increase in axon length. Activation of Shh pathway by a smoothened (SMO) agonist (SAG) or overexpression of SMO did not inhibit axon growth mediated by synaptamide or cyclopamine. Instead, adenylate cyclase inhibitor SQ22536 abolished synaptamide-mediated axon growth indicating requirement of cAMP elevation for this process. Our findings establish that synaptamide promotes axon growth while Shh antagonizes synaptamide-mediated cAMP elevation and axon growth by a SMO-independent, non-canonical pathway.

Summary: Synaptamide, an omega-3 fatty acid metabolite, promotes axon growth while Shh antagonizes synaptamide-mediated axon growth by a SMO-independent, non-canonical pathway.

Plasma non-esterified docosahexaenoic acid is the major pool supplying the brain

Despite being critical for normal brain function, the pools that supply docosahexaenoic acid (DHA) to the brain are not agreed upon. Using multiple kinetic models in free-living adult rats, we first demonstrate that DHA uptake from the plasma non-esterified fatty acid (NEFA) pool predicts brain uptake of DHA upon oral administration, which enters the plasma NEFA pool as well as multiple plasma esterified pools. The rate of DHA loss by the brain is similar to the uptake from the plasma NEFA pool. Furthermore, upon acute iv administration, although more radiolabeled lysophosphatidylcholine (LPC)-DHA enters the brain than NEFA-DHA, this is due to the longer plasma half-life and exposure to the brain. Direct comparison of the uptake rate of LPC-DHA and NEFA-DHA demonstrates that uptake of NEFA-DHA into the brain is 10-fold greater than LPC-DHA. In conclusion, plasma NEFA-DHA is the major plasma pool supplying the brain.