Selective deficits in the omega-3 fatty acid docosahexaenoic acid in the postmortem orbitofrontal cortex of patients with major depressive disorder

Exploring the shared genetic basis of major depressive disorder and frailty

BACKGROUND

Major depressive disorder (MDD) and frailty impose substantial health and economic burdens. MDD is recognized as a significant risk factor for frailty, but the genetic associations between these conditions remain unclear. This study investigates the genetic correlation, shared pleiotropic loci, causal relationships, and comorbid genes between MDD and frailty.

METHODS

The genetic correlation between MDD and frailty was assessed using linkage disequilibrium score regression (LDSC) based on data from genome-wide association studies (GWAS). A detailed analysis was performed to identify shared pleiotropic loci and causal relationships through cross-phenotype association tests and Mendelian randomization. Additionally, tissue enrichment analysis was conducted using stratified LDSC, gene-based associations with both conditions were assessed using Multimarker Analysis of Genomic Annotation (MAGMA), and pathway analysis of comorbid genes was performed using the g: GOSt tool.

RESULTS

Our findings revealed a significant positive genetic correlation between MDD and frailty (rg = 0.65, P = 1.49E-219). We identified 57 shared risk SNPs between the two conditions, including 6 novel SNPs. Mendelian randomization analyses indicated robust causal effects of MDD on frailty and vice versa. Furthermore, we observed tissue-specific heritability enrichment in 9 brain tissues. By combining MAGMA and CPASSOC analyses, we identified 10 comorbid genes associated with both MDD and frailty, primarily involved in synapse formation, modulation, plasticity, and desaturase activity.

CONCLUSION

This study provides strong evidence for a shared genetic basis between MDD and frailty. The identification of comorbid genes offers new insights into the mechanisms underlying the relationship between these conditions.

Unraveling brain palmitic acid: Origin, levels and metabolic fate

In the human brain, palmitic acid (16:0; PAM) comprises nearly half of total brain saturates and has been identified as the third most abundant fatty acid overall. Brain PAM supports the structure of membrane phospholipids, provides energy, and regulates protein stability. Sources underlying the origin of brain PAM are both diet and endogenous synthesis via de novo lipogenesis (DNL), primarily from glucose. However, studies investigating the origin of brain PAM are limited to tracer studies utilizing labelled (14C/11C/3H/2H) PAM, and results vary based on the model and tracer used. Nevertheless, there is evidence PAM is synthesized locally in the brain, in addition to obtained directly from the diet. Herein, we provide an overview of brain PAM origin, entry to the brain, metabolic fate, and factors influencing brain PAM kinetics and levels, the latter in the context of age, as well as neurological diseases and psychiatric disorders. Additionally, we briefly summarize the role of PAM in signaling at the level of the brain. We add to the literature a rudimentary summary on brain PAM metabolism.

Omega-3 Polyunsaturated Fatty Acids in Depression

Omega-3 polyunsaturated fatty acids have received considerable attention in the field of mental health, in particular regarding the treatment of depression. This review presents an overview of current research on the role of omega-3 fatty acids in the prevention and treatment of depressive disorders. The existing body of evidence demonstrates that omega-3 fatty acids, in particular eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), have antidepressant effects that can be attributed to their modulation of neuroinflammation, neurotransmitter function, and neuroplasticity. Nevertheless, clinical trials of omega-3 supplementation have yielded inconsistent results. Some studies have demonstrated significant reductions in depressive symptoms following omega-3 treatment, whereas others have shown minimal to no beneficial impact. A range of factors, encompassing dosage, the ratio of EPA to DHA, and baseline nutritional status, have been identified as having a potential impact on the noted results. Furthermore, it has been suggested that omega-3 fatty acids may act as an adjunctive treatment for those undergoing antidepressant treatment. Notwithstanding these encouraging findings, discrepancies in study designs and variability in individual responses underscore the necessity of further research in order to establish uniform, standardized guidelines for the use of omega-3 fatty acids in the management of depressive disorders.

Nutraceuticals in Psychiatric Disorders: A Systematic Review

Correct nutrition and diet are directly correlated with mental health, functions of the immune system, and gut microbiota composition. Diets with a high content of some nutrients, such as fibers, phytochemicals, and short-chain fatty acids (omega-3 fatty acids), seem to have an anti-inflammatory and protective action on the nervous system. Among nutraceuticals, supplementation of probiotics and omega-3 fatty acids plays a role in improving symptoms of several mental disorders. In this review, we collect data on the efficacy of nutraceuticals in patients with schizophrenia, autism spectrum disorders, major depression, bipolar disorder, and personality disorders. This narrative review aims to provide an overview of recent evidence obtained on this topic, pointing out the direction for future research.

Infant microbes and metabolites point to childhood neurodevelopmental disorders

This study has followed a birth cohort for over 20 years to find factors associated with neurodevelopmental disorder (ND) diagnosis. Detailed, early-life longitudinal questionnaires captured infection and antibiotic events, stress, prenatal factors, family history, and more. Biomarkers including cord serum metabolome and lipidome, human leukocyte antigen (HLA) genotype, infant microbiota, and stool metabolome were assessed. Among the 16,440 Swedish children followed across time, 1,197 developed an ND. Significant associations emerged for future ND diagnosis in general and for specific ND subtypes, spanning intellectual disability, speech disorder, attention-deficit/hyperactivity disorder, and autism. This investigation revealed microbiome connections to future diagnosis as well as early emerging mood and gastrointestinal problems. The findings suggest links to immunodysregulation and metabolism, compounded by stress, early-life infection, and antibiotics. The convergence of infant biomarkers and risk factors in this prospective, longitudinal study on a large-scale population establishes a foundation for early-life prediction and intervention in neurodevelopment.

Mental health in society's margins: poor n-3 PUFA intake and psychological well-being of homeless youth

Dietary intake of long-chain n-3 PUFA (n-3 PUFA), particularly EPA and DHA, has been associated with psychological well-being, but little is known about the n-3 PUFA intake of homeless youth. The current study determined the association between depression and anxiety symptoms and n-3 PUFA intake and erythrocytes status in homeless youth. Totally, 114 homeless youth aged 18-24 years were recruited from a drop-in centre. n-3 PUFA dietary intake was assessed using an FFQ, and erythrocytes status was determined by gas chromatography (GC). Linear regression models were used to determine the relationship between psychological well-being and n-3 PUFA intake and status. The mean intakes of EPA and DHA for all participants (0·06 ± 0·13 g/d and 0·11 ± 0·24 g/d) were well below recommended levels, and mean erythrocytes EPA + DHA (n-3 index) in the cohort (2·42 %) was lower than reported for healthy, housed adolescents and those with clinical depression. There was no association of n-3 PUFA intake and erythrocytes status with either depression or anxiety. However, the relationships of depression with dietary EPA (P = 0·017) and DHA (P = 0·008), as well as erythrocytes DHA (P = 0·007) and n 3-index (P = 0·009), were significantly moderated by sex even after adjusting for confounders. Specifically, among females, as the intake and status of these n-3 PUFA decreased, depression increased. Our findings show poor dietary intake and low erythrocytes status of n-3 PUFA among homeless youth, which is associated with depressive symptoms among females.

The role of polyunsaturated fatty acids in the neurobiology of major depressive disorder and suicide risk

Long-chain polyunsaturated fatty acids (LC-PUFAs) are obtained from diet or derived from essential shorter-chain fatty acids, and are crucial for brain development and functioning. Fundamentally, LC-PUFAs' neurobiological effects derive from their physicochemical characteristics, including length and double bond configuration, which differentiate LC-PUFA species and give rise to functional differences between n(omega)-3 and n-6 LC-PUFAs. LC-PUFA imbalances are implicated in psychiatric disorders, including major depression and suicide risk. Dietary intake and genetic variants in enzymes involved in biosynthesis of LC-PUFAs from shorter chain fatty acids influence LC-PUFA status. Domains impacted by LC-PUFAs include 1) cell signaling, 2) inflammation, and 3) bioenergetics. 1) As major constituents of lipid bilayers, LC-PUFAs are determinants of cell membrane properties of viscosity and order, affecting lipid rafts, which play a role in regulation of membrane-bound proteins involved in cell-cell signaling, including monoaminergic receptors and transporters. 2) The n-3:n-6 LC-PUFA balance profoundly influences inflammation. Generally, metabolic products of n-6 LC-PUFAs (eicosanoids) are pro-inflammatory, while those of n-3 LC-PUFAs (docosanoids) participate in the resolution of inflammation. Additionally, n-3 LC-PUFAs suppress microglial activation and the ensuing proinflammatory cascade. 3) N-3 LC-PUFAs in the inner mitochondrial membrane affect oxidative stress, suppressing production of and scavenging reactive oxygen species (ROS), with neuroprotective benefits. Until now, this wealth of knowledge about LC-PUFA biomechanisms has not been adequately tapped to develop translational studies of LC-PUFA clinical effects in humans. Future studies integrating neurobiological mechanisms with clinical outcomes may suggest ways to identify depressed individuals most likely to respond to n-3 LC-PUFA supplementation, and mechanistic research may generate new treatment strategies.

[Elucidation of the pathology of mental disorders focusing on polyunsaturated fatty acids and FABPs]

Polyunsaturated fatty acids (PUFAs) are essential for brain development and function, and an imbalance of brain PUFAs is linked to mental disorders like autism and schizophrenia. However, the cellular and molecular mechanisms underlying the effects of PUFAs on the brain remain largely unknown. Since they are insoluble in water, specific transporters like fatty acid binding proteins (FABPs), are required for transport and function of PUFAs within cells. We focused on the relationship between FABP-mediated homeostasis of brain PUFAs and neural plasticity. We found that FABP3, with a high affinity for n-6 PUFAs, is predominantly expressed in the GABAergic inhibitory interneurons of the anterior cingulate cortex (ACC) in the adult mouse brain. FABP3 knockout (KO) mice show increased GABA synthesis and inhibitory synaptic transmission in the ACC. We also found that FABP7 controls lipid raft function in astrocytes, and astrocytes lacking FABP7 exhibit changes in response to external stimuli. Furthermore, in FABP7 KO mice, dendritic protrusion formation in pyramidal neurons becomes abnormal, and we have reported a decrease in spine density and excitatory synaptic transmission. Here, we introduced recent advances in the understanding of the functions of PUFAs and FABPs in the brain, focusing especially on FABP3 and FABP7, in relation to human mental disorders.

Lipids in major depressive disorder: new kids on the block or old friends revisited?

Major depressive disorder (MDD) is a psychiatric mood disorder that results in substantial functional impairment and is characterized by symptoms such as depressed mood, diminished interest, impaired cognitive function, and vegetative symptoms such as disturbed sleep. Although the exact etiology of MDD is unclear, several underlying mechanisms (disturbances in immune response and/or stress response) have been associated with its development, with no single mechanism able to account for all aspects of the disorder. Currently, about 1 in 3 patients are resistant to current antidepressant therapies. Providing an alternative perspective on MDD could therefore pave the way for new, unexplored diagnostic and therapeutic solutions. The central nervous system harbors an enormous pool of lipids and lipid intermediates that have been linked to a plethora of its physiological functions. The aim of this review is therefore to provide an overview of the implications of lipids in MDD and highlight certain MDD-related underlying mechanisms that involve lipids and/or their intermediates. Furthermore, we will also focus on the bidirectional relationship between MDD and the lipid-related disorders obesity and type 2 diabetes.

Amphetamine-Related Fatalities and Altered Brain Chemicals: A Preliminary Investigation Using the Comparative Toxicogenomic Database

Amphetamine is a psychostimulant drug with a high risk of toxicity and death when misused. Abuse of amphetamines is associated with an altered organic profile, which includes omega fatty acids. Low omega fatty acid levels are linked to mental disorders. Using the Comparative Toxicogenomic Database (CTD), we investigated the chemical profile of the brain in amphetamine-related fatalities and the possibility of neurotoxicity. We classified amphetamine cases as low (0-0.5 g/mL), medium (>0.5 to 1.5 g/mL), and high (>1.5 g/mL), based on amphetamine levels in brain samples. All three groups shared 1-octadecene, 1-tridecene, 2,4-di-tert-butylphenol, arachidonic acid (AA), docosahexaenoic acid (DHA), eicosane, and oleylamide. We identified chemical-disease associations using the CTD tools and predicted an association between DHA, AA and curated conditions like autistic disorder, disorders related to cocaine, Alzheimer's disease, and cognitive dysfunction. An amphetamine challenge may cause neurotoxicity in the human brain due to a decrease in omega-3 fatty acids and an increase in oxidative products. Therefore, in cases of amphetamine toxicity, a supplement therapy may be needed to prevent omega-3 fatty acid deficiency.

The impact of lipid polyunsaturation on the physical and mechanical properties of lipid membranes

The lipid composition of cellular membranes and the balance between the different lipid components can be impacted by aging, certain pathologies, specific diets and other factors. This is the case in a subgroup of individuals with psychiatric disorders, such as schizophrenia, where cell membranes of patients have been shown to be deprived in polyunsaturated fatty acids (PUFAs), not only in brain areas where the target receptors are expressed but also in peripheral tissues. This PUFA deprivation thus represents a biomarker of such disorders that might impact not only the interaction of antipsychotic medications with these membranes but also the activation and signaling of the targeted receptors embedded in the lipid membrane. Therefore, it is crucial to understand how PUFAs levels alterations modulate the different physical properties of membranes. In this paper, several biophysical approaches were combined (Laurdan fluorescence spectroscopy, atomic force microscopy, differential scanning calorimetry, molecular modeling) to characterize membrane properties such as fluidity, elasticity and thickness in PUFA-enriched cell membranes and lipid model systems reflecting the PUFA imbalance observed in some diseases. The impact of both the number of unsaturations and their position along the chain on the above properties was investigated. Briefly, data revealed that PUFA presence in membranes increases membrane fluidity, elasticity and flexibility and decreases its thickness and order parameter. Both the level of unsaturation and their position affect these membrane properties.

Docosahexaenoic Acid Ameliorates Contextual Fear Memory Deficits in the Tg2576 Alzheimer's Disease Mouse Model: Cellular and Molecular Correlates

Docosahexaenoic acid (DHA), the most abundant polyunsaturated fatty acid in the brain, is essential for successful aging. In fact, epidemiological studies have demonstrated that increased intake of DHA might lower the risk for developing Alzheimer's disease (AD). These observations are supported by studies in animal models showing that DHA reduces synaptic pathology and memory deficits. Different mechanisms to explain these beneficial effects have been proposed; however, the molecular pathways involved are still unknown. In this study, to unravel the main underlying molecular mechanisms activated upon DHA treatment, the effect of a high dose of DHA on cognitive function and AD pathology was analyzed in aged Tg2576 mice and their wild-type littermates. Transcriptomic analysis of mice hippocampi using RNA sequencing was subsequently performed. Our results revealed that, through an amyloid-independent mechanism, DHA enhanced memory function and increased synapse formation only in the Tg2576 mice. Likewise, the IPA analysis demonstrated that essential neuronal functions related to synaptogenesis, neuritogenesis, the branching of neurites, the density of dendritic spines and the outgrowth of axons were upregulated upon-DHA treatment in Tg2576 mice. Our results suggest that memory function in APP mice is influenced by DHA intake; therefore, a high dose of daily DHA should be tested as a dietary supplement for AD dementia prevention.

Genes regulating levels of ω-3 long-chain polyunsaturated fatty acids are associated with alcohol use disorder and consumption, and broader externalizing behavior in humans

BACKGROUND

Individual variation in the physiological response to alcohol is predictive of an individual's likelihood to develop alcohol use disorder (AUD). Evidence from diverse model organisms indicates that the levels of long-chain polyunsaturated omega-3 fatty acids (ω-3 LC-PUFAs) can modulate the behavioral response to ethanol and therefore may impact the propensity to develop AUD. While most ω-3 LC-PUFAs come from diet, humans can produce these fatty acids from shorter chain precursors through a series of enzymatic steps. Natural variation in the genes encoding these enzymes has been shown to affect ω-3 LC-PUFA levels. We hypothesized that variation in these genes could contribute to the susceptibility to develop AUD.

METHODS

We identified nine genes (FADS1, FADS2, FADS3, ELOVL2, GCKR, ELOVL1, ACOX1, APOE, and PPARA) that are required to generate ω-3 LC-PUFAs and/or have been shown or predicted to affect ω-3 LC-PUFA levels. Using both set-based and gene-based analyses we examined their association with AUD and two AUD-related phenotypes, alcohol consumption, and an externalizing phenotype.

RESULTS

We found that the set of nine genes is associated with all three phenotypes. When examined individually, GCKR, FADS2, and ACOX1 showed significant association signals with alcohol consumption. GCKR was significantly associated with AUD. ELOVL1 and APOE were associated with externalizing.

CONCLUSIONS

Taken together with observations that dietary ω-3 LC-PUFAs can affect ethanol-related phenotypes, this work suggests that these fatty acids provide a link between the environmental and genetic influences on the risk of developing AUD.

Low omega-3 polyunsaturated fatty acids predict reduced response to standard antidepressants in patients with major depressive disorder

BACKGROUND

Major depressive disorder (MDD) is characterized by a high rate of treatment resistance. Omega (ω)-3 polyunsaturated fatty acids (PUFAs) were shown to correlate with depressive phenotype both in rodents and in humans. However, few studies to date have investigated the role of PUFAs in antidepressant response. The primary aim of this study was to assess the link between baseline PUFA composition and changes in depressive symptoms as well as antidepressant response in a multicenter study of depressed patients.

METHODS

Sixty depressed adults who met criteria for MDD according to DSM-IV-TR were recruited. Neuropsychiatric evaluations occurred at baseline and after 4 and 8 weeks of treatment with standard antidepressants, including escitalopram (N = 45), sertraline (N = 13) and venlafaxine (N = 2). At study endpoint, patients were stratified into responders (R) or non-responders (NR) based on their MADRS (Montgomery-Åsberg Depression Rating Scale) score. Baseline PUFA levels were assessed and their association with clinical response was determined.

RESULTS

Lower ω-3 PUFA levels were associated to worse baseline symptomatology. Baseline levels of PUFAs were significantly different between R and NR, with R exhibiting lower docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA) and ω-3 index; and higher ω-6/ω-3 ratio than NR before the start of antidepressant treatment. DHA levels as well as the ω-3 index and ω-6/ω-3 ratio significantly predicted response to antidepressants at study endpoint.

CONCLUSIONS

These results show that baseline levels of PUFAs predict later response to standard antidepressants in depressed subjects. They suggest that PUFA intake and/or metabolism represent a novel modifiable tool for the management of unresponsive depressed patients.

Fatty acid dysregulation in the anterior cingulate cortex of depressed suicides with a history of child abuse

Child abuse (CA) strongly increases the lifetime risk of suffering from major depression and predicts an unfavorable course for the illness. Severe CA has been associated with a specific dysregulation of oligodendrocyte function and thinner myelin sheaths in the human anterior cingulate cortex (ACC) white matter. Given that myelin is extremely lipid-rich, it is plausible that these findings may be accompanied by a disruption of the lipid profile that composes the myelin sheath. This is important to explore since the composition of fatty acids (FA) in myelin phospholipids can influence its stability, permeability, and compactness. Therefore, the objective of this study was to quantify and compare FA concentrations in postmortem ACC white matter in the choline glycerophospholipid pool (ChoGpl), a key myelin phospholipid pool, between adult depressed suicides with a history of CA (DS-CA) matched depressed suicides without CA (DS) and healthy non-psychiatric controls (CTRL). Total lipids were extracted from 101 subjects according to the Folch method and separated into respective classes using thin-layer chromatography. FA methyl esters from the ChoGpl fraction were quantified using gas chromatography. Our analysis revealed specific effects of CA in FAs from the arachidonic acid synthesis pathway, which was further validated with RNA-sequencing data. Furthermore, the concentration of most FAs was found to decrease with age. By extending the previous molecular level findings linking CA with altered myelination in the ACC, these results provide further insights regarding white matter alterations associated with early-life adversity.

Long-Term Fluoxetine Administration Causes Substantial Lipidome Alteration of the Juvenile Macaque Brain

Fluoxetine is an antidepressant commonly prescribed not only to adults but also to children for the treatment of depression, obsessive-compulsive disorder, and neurodevelopmental disorders. The adverse effects of the long-term treatment reported in some patients, especially in younger individuals, call for a detailed investigation of molecular alterations induced by fluoxetine treatment. Two-year fluoxetine administration to juvenile macaques revealed effects on impulsivity, sleep, social interaction, and peripheral metabolites. Here, we built upon this work by assessing residual effects of fluoxetine administration on the expression of genes and abundance of lipids and polar metabolites in the prelimbic cortex of 10 treated and 11 control macaques representing two monoamine oxidase A (MAOA) genotypes. Analysis of 8871 mRNA transcripts, 3608 lipids, and 1829 polar metabolites revealed substantial alterations of the brain lipid content, including significant abundance changes of 106 lipid features, accompanied by subtle changes in gene expression. Lipid alterations in the drug-treated animals were most evident for polyunsaturated fatty acids (PUFAs). A decrease in PUFAs levels was observed in all quantified lipid classes excluding sphingolipids, which do not usually contain PUFAs, suggesting systemic changes in fatty acid metabolism. Furthermore, the residual effect of the drug on lipid abundances was more pronounced in macaques carrying the MAOA-L genotype, mirroring reported behavioral effects of the treatment. We speculate that a decrease in PUFAs may be associated with adverse effects in depressive patients and could potentially account for the variation in individual response to fluoxetine in young people.

Mental Health in Childhood and Adolescence: The Role of Polyunsaturated Fatty Acids

There is increasing awareness of the importance of polyunsaturated fatty acids (PUFAs) for optimal brain development and function. In recent decades, researchers have confirmed the central role of PUFAs in a variety of patho-physiological processes. These agents modulate the mechanisms of brain cell signalling including the dopaminergic and serotonergic pathways. Therefore, nutritional insufficiencies of PUFAs may have adverse effects on brain development and developmental outcomes. The role of n-3 PUFAs has been studied in several psychiatric disorders in adulthood: schizophrenia, major depression, bipolar disorder, anxiety disorders, obsessive-compulsive disorder, post-traumatic stress disorder, attention deficit hyperactivity disorder (ADHD), autism spectrum disorders, eating disorders, substance use disorder, and borderline personality disorder. In contrast to the great number of studies conducted in adults, there are only limited data on the effects of n-3 PUFA supplementation in children and adolescents who suffer from mental disorders or show a high risk of developing psychiatric disorders. The aim of this review is to provide a complete and updated account of the available evidence of the impact of polyunsaturated fatty acids on developmental psychopathology in children and adolescents and the effect of fatty acid supplementation during developmental milestones, particularly in high-risk populations of children with minimal but detectable signs or symptoms of mental disorders.

Fatty acids and evolving roles of their proteins in neurological, cardiovascular disorders and cancers

The dysregulation of fat metabolism is involved in various disorders, including neurodegenerative, cardiovascular, and cancers. The uptake of long-chain fatty acids (LCFAs) with 14 or more carbons plays a pivotal role in cellular metabolic homeostasis. Therefore, the uptake and metabolism of LCFAs must constantly be in tune with the cellular, metabolic, and structural requirements of cells. Many metabolic diseases are thought to be driven by the abnormal flow of fatty acids either from the dietary origin and/or released from adipose stores. Cellular uptake and intracellular trafficking of fatty acids are facilitated ubiquitously with unique combinations of fatty acid transport proteins and cytoplasmic fatty acid-binding proteins in every tissue. Extensive data are emerging on the defective transporters and metabolism of LCFAs and their clinical implications. Uptake and metabolism of LCFAs are crucial for the brain's functional development and cardiovascular health and maintenance. In addition, data suggest fatty acid metabolic transporter can normalize activated inflammatory response by reprogramming lipid metabolism in cancers. Here we review the current understanding of how LCFAs and their proteins contribute to the pathophysiology of three crucial diseases and the mechanisms involved in the processes.

Reduced Cerebrospinal Fluid Levels of Lysophosphatidic Acid Docosahexaenoic Acid in Patients With Major Depressive Disorder and Schizophrenia

BACKGROUND

Lysophosphatidic acid (LPA) is involved in numerous biological processes, including neurodevelopment, chronic inflammation, and immunologic response in the central nervous system. Autotaxin (ATX) is a secreted enzyme that produces LPA from lysophosphatidylcholine (LPC). Previous studies have demonstrated decreased protein levels of ATX in cerebrospinal fluid (CSF) of patients with major depressive disorder (MDD). Based on those studies, the current study investigated the levels of lysophospholipids species including LPA and related metabolic enzymes, in CSF of patients with MDD and schizophrenia (SCZ).

METHODS

The levels of lysophospholipids species and related metabolic enzymes were measured with either liquid chromatography-tandem mass spectrometry or enzyme-linked immunosorbent assay. Japanese patients were diagnosed with DSM-IV-TR. CSF was obtained from age- and sex-matched healthy controls (n = 27) and patients with MDD (n = 26) and SCZ (n = 27).

RESULTS

Of all lysophospholipids species, the levels of LPA 22:6 (LPA - docosahexaenoic acid) were significantly lower in patients with MDD and SCZ than in healthy controls. These levels were negatively correlated with several clinical symptomatic scores of MDD, but not those of SCZ. In addition, the levels of LPA 22:6 were significantly correlated with the levels of LPC 22:6 among all 3 groups. On the other hand, the levels of LPA 22:6 were not correlated with ATX activity in patients with MDD and SCZ.

CONCLUSION

The lower levels of LPA 22:6 in patients with MDD and SCZ suggest an abnormality of LPA 22:6 metabolism. In addition, several depressive symptoms in patients with MDD were significantly associated with the lower levels of LPA 22:6, suggesting an involvement of LPA 22:6 in the pathophysiology of MDD.

Maternal Supply of Both Arachidonic and Docosahexaenoic Acids Is Required for Optimal Neurodevelopment

During the last trimester of gestation and for the first 18 months after birth, both docosahexaenoic acid,22:6n-3 (DHA) and arachidonic acid,20:4n-6 (ARA) are preferentially deposited within the cerebral cortex at a rapid rate. Although the structural and functional roles of DHA in brain development are well investigated, similar roles of ARA are not well documented. The mode of action of these two fatty acids and their derivatives at different structural-functional roles and their levels in the gene expression and signaling pathways of the brain have been continuously emanating. In addition to DHA, the importance of ARA has been much discussed in recent years for fetal and postnatal brain development and the maternal supply of ARA and DHA. These fatty acids are also involved in various brain developmental processes; however, their mechanistic cross talks are not clearly known yet. This review describes the importance of ARA, in addition to DHA, in supporting the optimal brain development and growth and functional roles in the brain.

Functional near-infrared spectroscopy during a decision-making task in patients with major depressive disorder

OBJECTIVE

Patients with major depressive disorder tend to exhibit poorer decision-making capacity than the general population, but neurobiological evidence is lacking. Functional near-infrared spectroscopy monitors changes in oxy-haemoglobin concentration in the cerebral cortex. It may provide an objective assessment of neurophysiological responses during decision-making processes. Thus, this study investigated the effect of major depressive disorder diagnosis and severity on prefrontal cortex activity during the Iowa gambling task.

METHODS

Right-handed healthy controls (n = 25) and patients with major depressive disorder (n = 25) were matched for age, gender, ethnicity and years of education in this cross-sectional study. Functional near-infrared spectroscopy signals and the responses made during a computerised Iowa gambling task were recorded. In addition, demographics, clinical history and symptom severity were noted.

RESULTS

Compared to healthy controls, patients with major depressive disorder had reduced haemodynamic response in several cortical regions of the frontal lobe (Hedge's g range from 0.71 to 1.52; p values range from ⩽0.001 to 0.041). Among patients, mean oxy-haemoglobin declined with major depressive disorder severity in the right orbitofrontal cortex (Pearson's r = -0.423; p = 0.024).

CONCLUSION

Haemodynamic dysfunction of the prefrontal cortex during decision-making processes is associated with major depressive disorder diagnosis and severity. These neurophysiological alterations may have a role in the decision-making capacity of patients with major depressive disorder.

Possible involvement of fatty acid binding proteins in psychiatric disorders

Polyunsaturated fatty acids (PUFAs) are essential for brain development and function. Increasing evidence has shown that an imbalance of PUFAs is associated with various human psychiatric disorders, including autism and schizophrenia. However, the mechanisms underlying the effects of PUFAs on brain functions at cellular and molecular levels remain unclear. Since PUFAs are insoluble in water, specific transporters are required to deliver PUFAs to appropriate intracellular compartments. Fatty acid-binding proteins (FABPs), the cellular chaperones of PUFAs, are involved in PUFA intracellular trafficking, signal transduction, and gene transcription. Therefore, we focused on the relationship between FABP-regulated PUFA homeostasis in the brain and neuronal plasticity. The authors previously reported that FABP3, which preferentially binds to n-6 PUFAs, is strongly expressed in the gamma-aminobutyric acid (GABAergic) inhibitory interneurons of the adult mouse anterior cingulate cortex (ACC), which is a component of the limbic cortex and is important for the coordination of cognitive and emotional behaviors. Interestingly, Fabp3 KO mice show increased GABA synthesis and abnormal excitatory/inhibitory balance in the ACC. In addition, studies have indicated that FABP7, which preferentially binds to n-3 PUFAs, controls lipid raft function in astrocytes, and astrocytic Fabp7 deficiency results in an altered response of astrocytes to external stimuli. Furthermore, Fabp7 KO mice exhibit aberrant dendritic morphology, and decreased spine density and excitatory synaptic transmission in pyramidal neurons. This review summarizes relationship between PUFAs or FABPs and human psychiatric disorders and discusses recent progress in elucidating the function of FABPs, especially FABP3 and 7, in the brain.

Maternal cafeteria diet exposure primes depression-like behavior in the offspring evoking lower brain volume related to changes in synaptic terminals and gliosis

Maternal nutritional programming by caloric exposure during pregnancy and lactation results in long-term behavioral modification in the offspring. Here, we characterized the effect of maternal caloric exposure on synaptic and brain morphological organization and its effects on depression-like behavior susceptibility in rats' offspring. Female Wistar rats were exposed to chow or cafeteria (CAF) diet for 9 weeks (pre-pregnancy, pregnancy, and lactation) and then switched to chow diet after weaning. By postnatal day 60, the male Wistar rat offspring were tested for depressive-like behavior using operational conditioning, novelty suppressed feeding, sucrose preference, and open-field test. Brain macro and microstructural morphology were analyzed using magnetic resonance imaging deformation-based morphometry (DBM) and western blot, immunohistochemistry for NMDA and AMPA receptor, synaptophysin and myelin, respectively. We found that the offspring of mothers exposed to CAF diet displayed deficient motivation showing decrease in the operant conditioning, sucrose preference, and suppressed feeding test. Macrostructural DBM analysis showed reduction in the frontomesocorticolimbic circuit volume including the nucleus accumbens (NAc), hippocampus, and prefrontal cortex. Microstructural analysis revealed reduced synaptic terminals in hippocampus and NAc, whereas increased glial fibrillary acidic protein in hippocampus and lateral hypothalamus, as well as a decrease in the hippocampal cell number and myelin reduction in the dentate gyrus and hilus, respectively. Also, offspring exhibited increase of the GluR1 and GLUR2 subunits of AMPA receptor, whereas a decrease in the mGluR2 expression in hippocampus. Our findings reveal that maternal programming might prime depression-like behavior in the offspring by modulating macro and micro brain organization of the frontomesocorticolimbic circuit.

Effect of one year krill oil supplementation on depressive symptoms and self-esteem of Dutch adolescents: A randomized controlled trial

INTRODUCTION

Observational studies have shown a relationship between omega-3 long-chain polyunsaturated fatty acids (n-3 LCPUFA) and depression in adolescents. However, n-3 LCPUFA supplementation studies investigating the potential improvement in depressive feelings in adolescents from the general population are missing.

METHODS

A one-year double-blind, randomized, placebo controlled krill oil supplementation trial was conducted in two cohorts. Cohort I started with 400 mg eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) or placebo, after three months this increased to 800 mg EPA and DHA per day, whilst cohort II started with this higher dose. Omega-3 Index (O3I) was monitored via finger-prick blood measurements. At baseline, six and 12 months participants completed the Centre for Epidemiologic Studies Depression Scale (CES-D) and the Rosenberg Self Esteem questionnaire (RSE). Adjusted mixed models were run with treatment allocation/O3I as predictor of CES-D and RSE scores.

RESULTS

Both intention-to-treat and assessing the change in O3I analyses did not show significant effects on CES-D or RSE scores.

CONCLUSION

There is no evidence for less depressive feelings, or higher self-esteem after one year of krill oil supplementation. However, due to a lack of adherence and drop-out issues, these results should be interpreted with caution.

Dietary intake of fish and n-3 polyunsaturated fatty acids and risk of postpartum depression: a nationwide longitudinal study - the Japan Environment and Children's Study (JECS)

BACKGROUND

Pregnant women require increased levels of n-3 polyunsaturated fatty acids (PUFAs) due to the demands of the growing fetus. Although some evidence indicates that maternal intake of fish and n-3 PUFAs is associated with reduced risk of postpartum depression, the results are inconsistent.

METHODS

We investigated whether dietary consumption of fish and/or n-3 PUFAs during pregnancy is associated with a reduced risk of maternal postpartum depression at 6 months after delivery and of serious mental illness at 1 year in a Japanese population. After exclusion and multiple imputation from a dataset comprising 103 062 pregnancies obtained in the Japan Environment and Children's Study, we evaluated 84 181 and 81 924 women at 6 months and 1 year after delivery, respectively.

RESULTS

Multivariable logistic regression showed a reduced risk of postpartum depression at 6 months in the second to fifth quintiles v. the lowest quintile for fish and n-3 PUFA intake, with trend tests also revealing a significant linear association. At 1 year after delivery, fish intake was associated with a reduced risk of serious mental illness in the second to fifth quintiles v. the lowest quintile for fish and in the third to fifth quintiles v. the lowest quintile for n-3 PUFA intake, with trend tests also revealing a significant linear association.

CONCLUSIONS

Women with higher fish and/or n-3 PUFA intake showed reduced risk of postpartum depression at 6 months after delivery and of serious mental illness at 1 year after delivery.

The Importance of Marine Omega-3s for Brain Development and the Prevention and Treatment of Behavior, Mood, and Other Brain Disorders

Most of the global population is deficient in long-chain marine omega-3s. In particular, docosahexaenoic acid (DHA), a long-chain omega-3 fatty acid, is important for brain and eye development. Additionally, DHA plays a significant role in mental health throughout early childhood and even into adulthood. In the brain, DHA is important for cellular membrane fluidity, function and neurotransmitter release. Evidence indicates that a low intake of marine omega-3s increases the risk for numerous mental health issues, including Attention Deficit Hyperactivity Disorder (ADHD), autism, bipolar disorder, depression and suicidal ideation. Studies giving supplemental marine omega-3s have shown promise for improving numerous mental health conditions. This paper will review the evidence surrounding marine omega-3s and mental health conditions.

The Association between Omega-3 Fatty Acid Intake and Human Brain Connectivity in Middle-Aged Depressed Women

Omega-3 fatty acid (n-3 FA) intake is known to have a preventive effect on depressive symptoms in a general population. This study assessed the effects of n-3 FA intake on depressive symptoms and brain function in middle-aged women. Depressive symptoms were screened using the Beck Depression Inventory-II (BDI-II) and Center for Epidemiologic Studies-Depression scale (CES-D) assessment questionnaires, and n-3 FA intakes were assessed using semiquantitative food frequency questionnaire. We found that n-3 FA intakes were negatively associated with depressive symptoms in middle-aged women. Psychiatrists diagnosed the presence of depressive disorders using the 5th edition of the Mental Disorder Diagnosis and Statistics Manual (DSM-5). Resting-state functional magnetic resonance imaging (rs-fMRI) was performed to investigate the association between n-3 FA intake and brain functional connectivity. Functional connectivity of the right middle frontal cortex (default mode network) and the right middle temporal pole (frontoparietal network) was positively associated with depressive symptom scores and negatively associated with n-3 FA intakes. In conclusion, high n-3 FA intake decreases the risk of depressive symptoms and modifies the brain functional connectivity in middle-aged women.

PUFA and their derivatives in neurotransmission and synapses: a new hallmark of synaptopathies

PUFA of the n-3 and n-6 families are present in high concentration in the brain where they are major components of cell membranes. The main forms found in the brain are DHA (22 :6, n-3) and arachidonic acid (20:4, n-6). In the past century, several studies pinpointed that modifications of n-3 and n-6 PUFA levels in the brain through dietary supply or genetic means are linked to the alterations of synaptic function. Yet, synaptopathies emerge as a common characteristic of neurodevelopmental disorders, neuropsychiatric diseases and some neurodegenerative diseases. Understanding the mechanisms of action underlying the activity of PUFA at the level of synapses is thus of high interest. In this frame, dietary supplementation in PUFA aiming at restoring or promoting the optimal function of synapses appears as a promising strategy to treat synaptopathies. This paper reviews the link between dietary PUFA, synapse formation and the role of PUFA and their metabolites in synaptic functions.

Causal Link between n-3 Polyunsaturated Fatty Acid Deficiency and Motivation Deficits

Reward-processing impairment is a common symptomatic dimension of several psychiatric disorders. However, whether the underlying pathological mechanisms are common is unknown. Herein, we asked if the decrease in the n-3 polyunsaturated fatty acid (PUFA) lipid species, consistently described in these pathologies, could underlie reward-processing deficits. We show that reduced n-3 PUFA biostatus in mice leads to selective motivational impairments. Electrophysiological recordings revealed increased collateral inhibition of dopamine D2 receptor-expressing medium spiny neurons (D2-MSNs) onto dopamine D1 receptor-expressing MSNs in the nucleus accumbens, a main brain region for the modulation of motivation. Strikingly, transgenically preventing n-3 PUFA deficiency selectively in D2-expressing neurons normalizes MSN collateral inhibition and enhances motivation. These results constitute the first demonstration of a causal link between a behavioral deficit and n-3 PUFA decrease in a discrete neuronal population and suggest that lower n-3 PUFA biostatus in psychopathologies could participate in the etiology of reward-related symptoms.

Microarray and Mass Spectrometry-Based Methodology for Lipid Profiling of Tissues and Cell Cultures

The recent developments in mass spectrometry have revealed the importance of lipids as biomarkers in the context of different diseases and as indicators of the cell's homeostasis. However, further advances are required to unveil the complex relationships between lipid classes and lipid species with proteins. Here, we present a new methodology that combines microarrays with mass spectrometry to obtain the lipid fingerprint of samples of a different nature in a standardized and fast way, with minimal sample consumption. As a proof of concept, we use the methodology to obtain the lipid fingerprint of 20 rat tissues and to create a lipid library for tissue classification. Then, we combine those results with immunohistochemistry and enzymatic assays to unveil the relationship between some lipid species and two enzymes. Finally, we demonstrate the performance of the methodology to explore changes in lipid composition of the nucleus accumbens from mice subjected to two lipid diets.

Docosahexaenoic acid,22:6n-3: Its roles in the structure and function of the brain

Docosahexaenoic acid,22:6n-3 (DHA) and its metabolites are vital for the structure and functional brain development of the fetus and infants, and also for maintenance of healthy brain function of adults. DHA is thought to be an essential nutrient required throughout the life cycle for the maintenance of overall brain health. The mode of actions of DHA and its derivatives at both cellular and molecular levels in the brain are emerging. DHA is the major prevalent fatty acid in the brain membrane. The brain maintains its fatty acid levels mainly via the uptake of plasma free fatty acids. Therefore, circulating plasma DHA is significantly related to cognitive abilities during ageing and is inversely associated with cognitive decline. The signaling pathways of DHA and its metabolites are involved in neurogenesis, antinociceptive effects, anti-apoptotic effect, synaptic plasticity, Ca²⁺ homeostasis in brain diseases, and the functioning of nigrostriatal activities. Mechanisms of action of DHA metabolites on various processes in the brain are not yet well known. Epidemiological studies support a link between low habitual intake of DHA and a higher risk of brain disorders. A diet characterized by higher intakes of foods containing high in n-3 fatty acids, and/or lower intake of n-6 fatty acids was strongly associated with a lower Alzheimer's Disease and other brain disorders. Supplementation of DHA improves some behaviors associated with attention deficit hyperactivity disorder, bipolar disorder, schizophrenia, and impulsive behavior, as well as cognition. Nevertheless, the outcomes of trials with DHA supplementation have been controversial. Many intervention studies with DHA have shown an apparent benefit in brain function. However, clinical trials are needed for definitive conclusions. Dietary deficiency of n-3 fatty acids during fetal development in utero and the postnatal state has detrimental effects on cognitive abilities. Further research in humans is required to assess a variety of clinical outcomes, including quality of life and mental status, by supplementation of DHA.

Association between PLA2G6 gene polymorphism for calcium-independent phospholipase A2 and nicotine dependence among males with schizophrenia

We investigated the relationship between the rs10798059 (BanI) and rs4375 polymorphisms in the phospholipase A2 (PLA2)G4A and PLA2G6 genes and the risk of nicotine dependence in 263 Croatian patients with schizophrenia. We also examined whether interactions between these polymorphisms and smoking contributed to schizophrenia onset and Positive and Negative Syndrome Scale (PANSS) psychopathology. We found no significant differences in the distribution of PLA2G4A genotypes and alleles according to smoking status, and no effect of the PLA2G4A genotype-smoking interaction on disease onset or PANSS. The PLA2G6-TT homozygous genotype was significantly overrepresented in male smokers compared to nonsmokers (34.7% vs. 17.1%, p < 0.05). These patients had ∼2.6-fold higher risk of becoming smokers than males with heterozygous PLA2G6-CT and homozygous PLA2G6-CC genotypes. In addition, male smokers without the PLA2G6-C allele (PLA2G6-TT homozygous) experienced earlier onset than nonsmoking homozygous PLA2G6-TT males. Thus, the PLA2G6 polymorphism affected the risk of nicotine dependence in male patients and the PLA2G6 genotype-smoking interaction was linked to the age of disease onset.

Deficiency or activation of peroxisome proliferator-activated receptor α reduces the tissue concentrations of endogenously synthesized docosahexaenoic acid in C57BL/6J mice

BACKGROUND/OBJECTIVES

Docosahexaenoic acid (DHA), an n-3 long chain polyunsaturated fatty acid (LCPUFA), is acquired by dietary intake or the in vivo conversion of α-linolenic acid. Many enzymes participating in LCPUFA synthesis are regulated by peroxisome proliferator-activated receptor alpha (PPARα). Therefore, it was hypothesized that the tissue accretion of endogenously synthesized DHA could be modified by PPARα.

MATERIALS/METHODS

The tissue DHA concentrations and mRNA levels of genes participating in DHA biosynthesis were compared among PPARα homozygous (KO), heterozygous (HZ), and wild type (WT) mice (Exp I), and between WT mice treated with clofibrate (PPARα agonist) or those not treated (Exp II). In ExpII, the expression levels of the proteins associated with DHA function in the brain cortex and retina were also measured. An n3-PUFA depleted/replenished regimen was applied to mitigate the confounding effects of maternal DHA.

RESULTS

PPARα ablation reduced the hepatic Acox, Fads1, and Fads2 mRNA levels, as well as the DHA concentration in the liver, but not in the brain cortex. In contrast, PPARα activation increased hepatic Acox, Fads1, Fads2 and Elovl5 mRNA levels, but reduced the DHA concentrations in the liver, retina, and phospholipid of brain cortex, and decreased mRNA and protein levels of the brain-derived neurotrophic factor in brain cortex.

CONCLUSIONS

LCPUFA enzyme expression was altered by PPARα. Either PPARα deficiency or activation-decreased tissue DHA concentration is a stimulus for further studies to determine the functional significance.

Diet-Derived Fatty Acids, Brain Inflammation, and Mental Health

Western societies experienced drastic changes in eating habits during the past century. The modern nutritional profile, typically rich in saturated fats and refined sugars, is recognized as a major contributing factor, along with reduced physical activity, to the current epidemics of metabolic disorders, notably obesity and diabetes. Alongside these conditions, recent years have witnessed a gradual and significant increase in prevalence of brain diseases, particularly mood disorders. While substantial clinical/epidemiological evidence supports a correlation between metabolic and neuropsychiatric disorders, the mechanisms of pathogenesis in the latter are often multifactorial and causal links have been hard to establish. Neuroinflammation stands out as a hallmark feature of brain disorders that may be linked to peripheral metabolic dyshomeostasis caused by an unhealthy diet. Dietary fatty acids are of particular interest, as they may play a dual role, both as a component of high-calorie obesogenic diets and as signaling molecules involved in inflammatory responses. Here, we review current literature connecting diet-related nutritional imbalance and neuropsychiatric disorders, focusing on the role of dietary fatty acids as signaling molecules directly relevant to inflammatory processes and to neuronal function.

Perinatal Nutrition and Programmed Risk for Neuropsychiatric Disorders: A Focus on Animal Models

Maternal nutrition is critically important for fetal development. Recent human studies demonstrate a strong connection between diet during pregnancy and offspring risk for neuropsychiatric disorders including depression, anxiety, and attention-deficit/hyperactivity disorder. Animal models have emerged as a crucial tool for understanding maternal nutrition's contribution to prenatal programming and the later development of neuropsychiatric disorders. This review highlights preclinical studies examining how maternal consumption of the three macronutrients (protein, fats, and carbohydrates) influence offspring negative-valence behaviors relevant to neuropsychiatric disorders. We highlight the translational aspects of animal models and so examine exposure periods that mirror the neurodevelopmental stages of human gestation. Because of our emphasis on programmed changes in neurobehavioral development, studies that continue diet exposure until assessment in adulthood are not discussed. The presented research provides a strong foundation of preclinical evidence of nutritional programming of neurobehavioral impairments. Alterations in risk assessment and response were observed alongside neurodevelopmental impairments related to neurogenesis, synaptogenesis, and synaptic plasticity. To date, the large majority of studies utilized rodent models, and the field could benefit from additional study of large-animal models. Additional future directions are discussed, including the need for further studies examining how sex as a biological variable affects the contribution of maternal nutrition to prenatal programming.

Omega-3 Polyunsaturated Fatty Acid Deficiency and Progressive Neuropathology in Psychiatric Disorders: A Review of Translational Evidence and Candidate Mechanisms

Meta-analytic evidence indicates that mood and psychotic disorders are associated with both omega-3 polyunsaturated fatty acid (omega-3 PUFA) deficits and progressive regional gray and white matter pathology. Although the association between omega-3 PUFA insufficiency and progressive neuropathological processes remains speculative, evidence from translational research suggests that omega-3 PUFA insufficiency may represent a plausible and modifiable risk factor not only for enduring neurodevelopmental abnormalities in brain structure and function, but also for increased vulnerability to neurodegenerative processes. Recent evidence from human neuroimaging studies suggests that lower omega-3 PUFA intake/status is associated with accelerated gray matter atrophy in healthy middle-aged and elderly adults, particularly in brain regions consistently implicated in mood and psychotic disorders, including the amygdala, anterior cingulate, hippocampus, prefrontal cortex, and temporal cortex. Human neuroimaging evidence also suggests that both low omega-3 PUFA intake/status and psychiatric disorders are associated with reductions in white matter microstructural integrity and increased rates of white matter hyperintensities. Preliminary evidence suggests that increasing omega-3 PUFA status is protective against gray matter atrophy and deficits in white matter microstructural integrity in patients with mood and psychotic disorders. Plausible mechanisms mediating this relationship include elevated pro-inflammatory signaling, increased synaptic regression, and reductions in cerebral perfusion. Together these associations encourage additional neuroimaging research to directly investigate whether increasing omega-3 PUFA status can mitigate neuropathological processes in patients with, or at high risk for, psychiatric disorders.

Anxiolytic- and Antidepressant-Like Effects of Fish Oil-Enriched Diet in Brain-Derived Neurotrophic Factor Deficient Mice

Despite significant advances in the understanding of the therapeutic activity of antidepressant drugs, treatment-resistant depression is a public health issue prompting research to identify new therapeutic strategies. Evidence strongly suggests that nutrition might exert a significant impact on the onset, the duration and the severity of major depression. Accordingly, preclinical and clinical investigations demonstrated the beneficial effects of omega-3 fatty acids in anxiety and mood disorders. Although the neurobiological substrates of its action remain poorly documented, basic research has shown that omega-3 increases brain-derived neurotrophic factor (BDNF) levels in brain regions associated with depression, as antidepressant drugs do. In contrast, low BDNF levels and hippocampal atrophy were observed in animal models of depression. In this context, the present study compared the effects of long-lasting fish oil-enriched diet, an important source of omega-3 fatty acids, between heterozygous BDNF^+/- mice and their wild-type littermates. Our results demonstrated lower activation of Erk in BDNF^+/- mice whereas this deficit was rescued by fish oil-enriched diet. In parallel, BDNF^+/- mice displayed elevated hippocampal extracellular 5-HT levels in relation with a local decreased serotonin transporter protein level. Fish oil-enriched diet restored normal serotonergic tone by increasing the protein levels of serotonin transporter. At the cellular level, fish oil-enriched diet increased the pool of immature neurons in the dentate gyrus of BDNF^+/- mice and the latter observations coincide with its ability to promote anxiolytic- and antidepressant-like response in these mutants. Collectively, our results demonstrate that the beneficial effects of long-term exposure to fish oil-enriched diet in behavioral paradigms known to recapitulate diverse abnormalities related to the depressive state specifically in mice with a partial loss of BDNF. These findings contrast with the mechanism of action of currently available antidepressant drugs for which the full manifestation of their therapeutic activity depends on the enhancement of serotoninergic and BDNF signaling. Further studies are warranted to determine whether fish oil supplementation could be used as an add-on strategy to conventional pharmacological interventions in treatment-resistant patients and relevant animal models.

Omega-3 polyunsaturated fatty acid supplementation in prevention and treatment of maternal depression: Putative mechanism and recommendation

BACKGROUND

Women are vulnerable to depression during their childbearing years, and giving birth to a child precipitates postpartum depression (PPD) in some women. This review focuses on comparing the effectiveness of omega-3 polyunsaturated fatty acid supplementation on depression during pregnancy or PPD after childbirth.

METHODS

MEDLINE, PubMed, PsycINFO, and the Cochrane Collaboration Registry of Controlled Trials etc. through July 2017 were searched. Studies of dietary intake and plasma and/or milk levels of omega-3 fatty acids and trials of benefits and effects of omega-3 fatty acids supplements on pregnant or postpartum women with depression were specifically selected.

RESULTS

Omega-3 fatty acid deficiency, due to inadequate intake, fast depletion during pregnancy and lactation, is one of the risk factors of PPD. Associations between neuroinflammation (elevated pro-inflammatory cytokines) and aberrant neurotransmission (low serotonergic transmission activity) and risk of PPD have also been reported by numerous studies. Supplementation with eicosapentaenoic acid (EPA)-rich oil can effectively reduce depression during pregnancy and PPD after childbirth. Long term treatment with docosahexaenoic acid (DHA)-rich oil can be effective in reducing the risk of PPD in healthy women, but not in lactating women. Supplementation of DHA-rich oil to women begun at pregnancy and continued after childbirth exerts no beneficial effect on depression.

CONCLUSIONS

Dietary supplementation with omega-3 fatty acids rich in EPA during pregnancy or postpartum reduces some symptoms associated with depression. DHA supplementation to healthy pregnant women can also reduce the risk of PPD.

Association of Use of Omega-3 Polyunsaturated Fatty Acids With Changes in Severity of Anxiety Symptoms: A Systematic Review and Meta-analysis

IMPORTANCE

No systematic review or meta-analysis has assessed the efficacy of omega-3 polyunsaturated fatty acids (PUFAs) for anxiety.

OBJECTIVE

To evaluate the association of anxiety symptoms with omega-3 PUFA treatment compared with controls in varied populations.

DATA SOURCES

PubMed, Embase, ProQuest, ScienceDirect, Cochrane Library, ClinicalKey, Web of Science, and ClinicalTrials.gov databases were searched up to March 4, 2018.

STUDY SELECTION

A search was performed of clinical trials assessing the anxiolytic effect of omega-3 PUFAs in humans, in either placebo-controlled or non-placebo-controlled designs. Of 104 selected articles, 19 entered the final data extraction stage.

DATA EXTRACTION AND MEASURES

Two authors independently extracted the data according to a predetermined list of interests. A random-effects model meta-analysis was performed and this study was conducted based on Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines.

MAIN OUTCOMES AND MEASURES

Changes in the severity of anxiety symptoms after omega-3 PUFA treatment.

RESULTS

In total, 1203 participants with omega-3 PUFA treatment (mean age, 43.7 years; mean female proportion, 55.0%; mean omega-3 PUFA dosage, 1605.7 mg/d) and 1037 participants without omega-3 PUFA treatment (mean age, 40.6 years; mean female proportion, 55.0%) showed an association between clinical anxiety symptoms among participants with omega-3 PUFA treatment compared with control arms (Hedges g, 0.374; 95% CI, 0.081-0.666; P = .01). Subgroup analysis showed that the association of treatment with reduced anxiety symptoms was significantly greater in subgroups with specific clinical diagnoses than in subgroups without clinical conditions. The anxiolytic effect of omega-3 PUFAs was significantly better than that of controls only in subgroups with a higher dosage (at least 2000 mg/d) and not in subgroups with a lower dosage (<2000 mg/d).

CONCLUSIONS AND RELEVANCE

This review indicates that omega-3 PUFAs might help to reduce the symptoms of clinical anxiety. Further well-designed studies are needed in populations in whom anxiety is the main symptom.

The Role of Physical Exercise and Omega-3 Fatty Acids in Depressive Illness in the Elderly

Background:

In adulthood, depression is the most common type of mental illness and will be the second leading cause of disease by 2020. Major depression dramatically affects the function of the central nervous system and degrades the quality of life, especially in old age.

Several mechanisms underlie the pathophysiology of depressive illness, since it has a multifactorial etiology. Human and an-imal studies have demonstrated that depression is mainly associated with imbalances in neurotransmitters and neurotrophins, hypothalamic-pituitary-adrenal axis alterations, brain volume changes, neurogenesis dysfunction, and dysregulation of in-flammatory pathways. Also the gut microbiota may influence mental health outcomes.

Although depression is not a consequence of normal aging, depressive disorders are common in later life, even if often undi-agnosed or mis-diagnosed in old age. When untreated, depression reduces life expectancy, worsens medical illnesses, en-hances health care costs and is the primary cause of suicide among older people. To date, the underpinnings of depression in the elderly are still to be understood, and the pharmacological treatment is the most commonly used therapy.

Objective:

Since a sedentary lifestyle and poor eating habits have recently emerged as crucial contributors to the genesis and course of depression, in the present review, we have focused on the effects of physical activity and omega-3 fatty acids on depressive illness in the elderly.

Results:

A growing literature indicates that both exercise and dietary interventions can promote mental health throughout one’s lifespan.

Conclusion:

There thus emerges the awareness that an active lifestyle and a balanced diet may constitute valid low-cost pre-vention strategies to counteract depressive illness in the elderly.

Food for Mood: Relevance of Nutritional Omega-3 Fatty Acids for Depression and Anxiety

The central nervous system (CNS) has the highest concentration of lipids in the organism after adipose tissue. Among these lipids, the brain is particularly enriched with polyunsaturated fatty acids (PUFAs) represented by the omega-6 (ω6) and omega-3 (ω3) series. These PUFAs include arachidonic acid (AA) and docosahexaenoic acid (DHA), respectively. PUFAs have received substantial attention as being relevant to many brain diseases, including anxiety and depression. This review addresses an important question in the area of nutritional neuroscience regarding the importance of ω3 PUFAs in the prevention and/or treatment of neuropsychiatric diseases, mainly depression and anxiety. In particular, it focuses on clinical and experimental data linking dietary intake of ω3 PUFAs and depression or anxiety. In particular, we will discuss recent experimental data highlighting how ω3 PUFAs can modulate neurobiological processes involved in the pathophysiology of anxiety and depression. Potential mechanisms involved in the neuroprotective and corrective activity of ω3 PUFAs in the brain are discussed, in particular the sensing activity of free fatty acid receptors and the activity of the PUFAs-derived endocannabinoid system and the hypothalamic-pituitary-adrenal axis.

Alterations in peripheral fatty acid composition in bipolar and unipolar depression

BACKGROUND

Lipid metabolism has been shown to play an important role in unipolar and bipolar depression. In this study, we aimed to evaluate levels of fatty acids in patients with unipolar (MDD) and bipolar depression (BDD) in comparison to patients with bipolar disorder in euthymia (BDE) and non-psychiatric controls.

METHODS

Levels of saturated fatty acids (SFAs), monounsaturated fatty acids (MUFAs) and polyunsaturated fatty acids (PUFAs) were assessed in serum of (87) patients with BD (31 euthymic, 22 depressive) or MDD (34) and (31) non-psychiatric controls through GC-FID.

RESULTS

No significant difference in total levels of PUFAs (polyunsaturated fatty acids), SFAs (saturated fatty acids), MUFAs (monounsaturated fatty acids) and total fatty acids were found between groups. Our results demonstrated higher levels AA: EPA and AA: EPA+DHA in patients with BDD. Additionally, we observed that overall omega-6 present a positive correlation with illness duration in patients with BDD and AA: EPA ratio positively associated with illness duration in MDD group. Depression severity was positively associated with AA: EPA+DHA ratio in all participants.

CONCLUSION

Together, our results support the relevance for the balance of omega-3 and omega-6 in BDD. Also, our results suggest a potential subset of stage-related lipid biomarkers that further studies are needed to help clarify the dynamics of lipid alteration in BD and MDD.

Exposure to an obesogenic diet during adolescence leads to abnormal maturation of neural and behavioral substrates underpinning fear and anxiety

BACKGROUND

Post-traumatic stress disorder (PTSD) and obesity are highly prevalent in adolescents. Emerging findings from our laboratory and others are consistent with the novel hypothesis that obese individuals may be predisposed to developing PTSD. Given that aberrant fear responses are pivotal in the pathogenesis of PTSD, the objective of this study was to determine the impact of an obesogenic Western-like high-fat diet (WD) on neural substrates associated with fear.

METHODS

Adolescent Lewis rats (n = 72) were fed with either the experimental WD (41.4% kcal from fat) or the control diet. The fear-potentiated startle paradigm was used to determine sustained and phasic fear responses. Diffusion tensor imaging metrics and T2 relaxation times were used to determine the structural integrity of the fear circuitry including the medial prefrontal cortex (mPFC) and the basolateral complex of the amygdala (BLA).

RESULTS

The rats that consumed the WD exhibited attenuated fear learning and fear extinction. These behavioral impairments were associated with oversaturation of the fear circuitry and astrogliosis. The BLA T2 relaxation times were significantly decreased in the WD rats relative to the controls. We found elevated fractional anisotropy in the mPFC of the rats that consumed the WD. We show that consumption of a WD may lead to long-lasting damage to components of the fear circuitry.

CONCLUSIONS

Our findings demonstrate that consumption of an obesogenic diet during adolescence has a profound impact in the maturation of the fear neurocircuitry. The implications of this research are significant as they identify potential biomarkers of risk for psychopathology in the growing obese population.

Exploring the association between whole blood Omega-3 Index, DHA, EPA, DHA, AA and n-6 DPA, and depression and self-esteem in adolescents of lower general secondary education

Purpose

Depression is common in adolescents and long-chain polyunsaturated fatty acids (LCPUFA) are suggested to be associated with depression. However, research in adolescents is limited. Furthermore, self-esteem has never been studied in relation to LCPUFA. The objective here was to determine associations of depression and self-esteem with eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), Omega-3 Index (O3I), n-6 docosapentaenoic acid (n-6 DPA, also called Osbond acid, ObA), n-3 docosapentaenoic acid (DPA), and arachidonic acid (AA) concentrations in blood of adolescents attending lower general secondary education (LGSE).

Methods

Baseline cross-sectional data from a krill oil supplementation trial in adolescents attending LGSE with an O3I ≤ 5% were analysed using regression models built with the BayesFactor package in R. Fatty acids and O3I were determined in blood. Participants filled out the Centre for Epidemiologic Studies Depression (CES-D) scale and the Rosenberg Self-Esteem scale (RSE).

Results

Scores indicative of depression (CES-D ≥ 16) were found in 29.4% of the respondents. Of all fatty acids, we found extreme evidence [Bayes factor (BF) > 100] for a weak negative association between ObA and depression score [− 0.16; 95% credible interval (CI) − 0.28 to − 0.04; BF₁₀ = 245], and substantial evidence for a weak positive association between ObA and self-esteem score (0.09; 95% CI, − 0.03 to 0.20; BF₁₀ = 4). When all fatty acids were put in one model as predictors of CES-D or RSE, all of the 95% CI contained 0, i.e., no significant association.

Conclusion

No evidence was found for associations of DHA, EPA and O3I with depression or self-esteem scores in LGSE adolescents with O3I ≤ 5%. The associations of higher ObA status with lower depression and higher self-esteem scores warrant more research.

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.

Associations between Proportion of Plasma Phospholipid Fatty Acids, Depressive Symptoms and Major Depressive Disorder. Cross-Sectional Analyses from the AGES Reykjavik Study

BACKGROUND

Deficits in n-3 fatty acids may be associated with depression. However, data are scarce from older adults who are at greater risk of poor dietary intake and of developing depression.

OBJECTIVE

To investigate proportion of plasma phospholipid fatty acids with respect to depressive symptoms and major depressive disorder in community dwelling older adults.

METHODS

Cross-sectional analyses of 1571 participants in the Age, Gene/Environment Susceptibility (AGES)-Reykjavik Study aged 67-93 years. Depressive symptoms were measured using the 15-item Geriatric Depression Scale (GDS-15). Major depressive disorder was assessed according to Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) criteria using the Mini-International Neuropsychiatric Interview (MINI).

RESULTS

Depressive symptoms were observed in 195 (12.4%) subjects and there were 27 (1.7%) cases of major depressive disorder. Participants with depressive symptoms were less educated, more likely to be smokers, less physically active and consumed cod liver oil less frequently. Difference in GDS-15 scores by tertiles of n-3 fatty acid proportion was not significant. Proportion of long chain n-3 fatty acids (Eicosapentaenoic- + Docosahexaenoic acid) were inversely related to major depressive disorder, (tertile 2 vs. tertile 1) OR: 0.31 (95% CI: 0.11, 0.86); tertile 3 vs. tertile 1, OR: 0.45 (95% CI: 0.17, 1.21).

CONCLUSION

In our cross sectional analyses low proportions of long chain n-3 fatty acids in plasma phospholipids appear to be associated with increased risk of major depressive disorder. However, the results from this study warrant further investigation in prospective setting with sufficiently long follow-up.

Maternal dietary of n-3 polyunsaturated fatty acids affects the neurogenesis and neurochemical in female rat at weaning

Long-chain polyunsaturated fatty acids (LC-PUFAs) are rapidly accumulated in brain during pre- and neonatal life, which is important for the development and function of central nervous system. Deficiency of biologically important n-3 PUFA docosahexaenoic acid (C22:6n-3, DHA) is associated with impaired visual, attention and cognition, and would precipitate psychiatric symptoms. However, clinical studies of the potential mechanism on the effect of dietary DHA deficiency on neural development remain unclear. In addition, the effects of n-6 PUFAs and n-3 PUFAs ingestion on the dynamic process of the cell proliferation in neurogenesis of offspring were investigated using immunefluorescence. And GC-MS was used to determine the fatty acid content in the liver of offspring. To further investigate the neurochemical influence on maternal PUFAs levels, we assessed the functioning of various neurotransmitter systems including glutamatergic, dopaminergic, norepinephrinergic and serotoninergic systems in the brain of female rats at weaning by HPLC-MS/MS. Lastly, we analyzed the turnover rates and between-metabolite ratios (the ratios between metabolites of monoamine neurotransmitters) to seek potential links between the neurotransmitters and dietary fatty acids compositions. There were significant differences between the deficiency group and the control or supplementary group in liver fatty acids compositions, showing that n-3 PUFAs were largely replaced by n-6 PUFAs. The generation of n-3 PUFAs deficiency rats exhibited abnormal neurogenesis and neurochemical. Altered dopamine or norepinephrine transmission and between-metabolite ratios in brain areas may be a key neuronal mechanism that contributes to the potential detrimental effects of n-3 PUFAs deficiency for mental health.