Elevated production of docosahexaenoic acid in females: potential molecular mechanisms

An association between PPARα-L162V polymorphism and increased plasma LDL cholesterol levels after risperidone treatment

Peroxisome proliferator-activated receptor alpha (PPARα) and antipsychotic medications both influence polyunsaturated fatty acids (PUFA) homeostasis, and thus PPARα polymorphism may be linked to antipsychotic treatment response. Here we investigated whether the functional leucine 162 valine (L162V) polymorphism in PPARα influenced antipsychotic treatment in a group of psychosis patients (N = 186), as well as in a patient subgroup with risperidone, paliperidone, or combination treatment (N = 65). Antipsychotic-naïve first-episode patients and nonadherent chronic individuals were genotyped by polymerase chain reaction analysis. At baseline, and after 8 weeks of treatment with various antipsychotic medications, we assessed the patients' Positive and Negative Syndrome Scale (PANSS) scores; PANSS factors; and metabolic syndrome-related parameters, including fasting plasma lipid and glucose levels, and body mass index. In the total patient group, PPARα polymorphism did not affect PANSS psychopathology or metabolic parameters. However, in the subgroup of patients with risperidone, paliperidone, or combination treatment, PPARα polymorphism influenced changes in plasma LDL cholesterol. Specifically, compared to PPARα-L162L homozygous patients, PPARα-L162V heterozygous individuals exhibited significantly higher increases of LDL cholesterol levels after antipsychotic treatment. The PPARα polymorphism had a strong effect size, but a relatively weak contribution to LDL cholesterol level variations (∼12.8 %).

Prenatal THC exposure induces long-term, sex-dependent cognitive dysfunction associated with lipidomic and neuronal pathology in the prefrontal cortex-hippocampal network

With increasing maternal cannabis use, there is a need to investigate the lasting impact of prenatal exposure to Δ9-tetrahydrocannabinol (THC), the main psychotropic compound in cannabis, on cognitive/memory function. The endocannabinoid system (ECS), which relies on polyunsaturated fatty acids (PUFAs) to function, plays a crucial role in regulating prefrontal cortical (PFC) and hippocampal network-dependent behaviors essential for cognition and memory. Using a rodent model of prenatal cannabis exposure (PCE), we report that male and female offspring display long-term deficits in various cognitive domains. However, these phenotypes were associated with highly divergent, sex-dependent mechanisms. Electrophysiological recordings revealed hyperactive PFC pyramidal neuron activity in both males and females, but hypoactivity in the ventral hippocampus (vHIPP) in males, and hyperactivity in females. Further, cortical oscillatory activity states of theta, alpha, delta, beta, and gamma bandwidths were strongly sex divergent. Moreover, protein expression analyses at postnatal day (PD)21 and PD120 revealed primarily PD120 disturbances in dopamine D1R/D2 receptors, NMDA receptor 2B, synaptophysin, gephyrin, GAD67, and PPARα selectively in the PFC and vHIPP, in both regions in males, but only the vHIPP in females. Lastly, using matrix-assisted laser desorption/ionization imaging mass spectrometry (MALDI IMS), we identified region-, age-, and sex-specific deficiencies in specific neural PUFAs, namely docosahexaenoic acid (DHA) and arachidonic acid (ARA), and related metabolites, in the PFC and hippocampus (ventral/dorsal subiculum, and CA1 regions). This study highlights several novel, long-term and sex-specific consequences of PCE on PFC-hippocampal circuit dysfunction and the potential role of specific PUFA signaling abnormalities underlying these pathological outcomes.

Dietary and plasma retinoids are not associated with fatty acid desaturase indices in healthy young adults

Past research in rodents suggests that fatty acid (FA) desaturase expression and activity may be modified by vitamin A; however, this has not been investigated in humans. The primary objective of this study was to examine associations between dietary retinoid intakes, plasma retinoid concentrations, and FA desaturase indices in young adults. As a secondary objective, biological sex and estrogen-containing contraceptive (EC) use were investigated due to prior evidence demonstrating that both can influence plasma retinol concentration and FA desaturase indices. Dietary retinoid intake (food frequency questionnaire), plasma retinoid concentrations (high-performance liquid chromatography-tandem mass spectrometry), plasma FA (gas chromatography), and FA desaturase indices (product-to-precursor ratios) from 945 adults recruited for the cross-sectional Toronto Nutrigenomics and Health study were analyzed. Participants were stratified into quartiles based on plasma retinol concentration and data analyzed by one-way analysis of covariance. Dietary retinoid intakes were not associated with the overall n-3 pathway, overall n-6 pathway, delta-5 desaturase, delta-6 desaturase, or delta-9 desaturase indices (all r < 0.10, p > 0.05). The overall n-6 pathway index was significantly higher (p = 0.0004) and the delta-5 desaturase index was significantly lower (p = 0.0003) in individuals with higher plasma retinol levels; however, these differences were lost when participants were grouped by biological sex and EC use. Although weak relationships were observed between plasma retinol and some FA desaturase indices in the total population, these associations appear to be driven by biological sex and EC usage rather than retinoids. We therefore find little evidence of a relationship between retinoids and FA desaturase indices in young, healthy adults.

Association between PLA2 gene polymorphisms and treatment response to antipsychotic medications: A study of antipsychotic-naïve first-episode psychosis patients and nonadherent chronic psychosis patients

Here we investigated whether antipsychotic treatment was influenced by three polymorphisms: rs10798059 (BanI) in the phospholipase A2 (PLA2)G4A gene, rs4375 in PLA2G6, and rs1549637 in PLA2G4C. A total of 186 antipsychotic-naïve first-episode psychosis patients or nonadherent chronic psychosis individuals (99 males and 87 females) were genotyped by polymerase chain reaction analysis/restriction fragment length polymorphism. At baseline, and after 8 weeks of treatment with various antipsychotic medications, we assessed patients' Positive and Negative Syndrome Scale (PANSS) scores, PANSS factors, and metabolic syndrome-related parameters (fasting plasma lipid and glucose levels, and body mass index). We found that PLA2G4A polymorphism influenced changes in PANSS psychopathology, and PLA2G6 polymorphism influenced changes in PANSS psychopathology and metabolic parameters. PLA2G4C polymorphism did not show any impact on PANSS psychopathology or metabolic parameters. The polymorphisms' effect sizes were estimated as moderate to strong, with contributions ranging from around 6.2-15.7%. Furthermore, the polymorphisms' effects manifested in a gender-specific manner.

Sex differences in hippocampal-dependent memory and the hippocampal lipidome in adolescent rats raised on diets with or without DHA

Recent studies suggest the effects of DHA supplementation on human memory may differ between females and males during infancy, adolescence, and early adulthood, but the underlying mechanisms are not clear. As a result, this study sought to examine the spatial memory and brain lipidomic profiles in female and male adolescent rats with or without a DHA-enriched diet that began perinatally with the supplementation of dams. Spatial learning and memory were examined in adolescent rats using the Morris Water Maze beginning at 6 weeks of age and animals were sacrificed at 7 weeks of age to permit isolation of brain tissue and blood samples. Behavioral testing showed that there was a significant diet x sex interaction for two key measures of spatial memory (distance to zone and time spent in the correct quadrant during the probe test), with female rats benefiting the most from DHA supplementation. Lipidomic analyses suggest levels of arachidonic acid (ARA) and n-6 docosapentaenoic acid (DPA) containing phospholipid species were lower in the hippocampus of DHA supplemented compared with control animals, and principal component analyses revealed a potential dietary treatment effect for hippocampal PUFA. Females fed DHA had slightly more PE P-18:0_22:6 and maintained levels of PE 18:0_20:4 in the hippocampus in contrast with males fed DHA. Understanding how DHA supplementation during the perinatal and adolescent periods changes cognitive function in a sex-specific manner has important implications for determining the dietary requirements of DHA. This study adds to previous work highlighting the importance of DHA for spatial memory and provides evidence that further research needs to consider how DHA supplementation can cause sex-specific changes.

Hepatic PPARα Is Destabilized by SIRT1 Deacetylase in Undernourished Male Mice

The nutrient sensing nuclear receptor peroxisome proliferator-activated receptor-α (PPARα) regulates the host response to short-term fasting by inducing hepatic transcriptional programming of ketogenesis, fatty acid oxidation and transport, and autophagy. This adaptation is ineffective in chronically undernourished individuals, among whom dyslipidemia and hepatic steatosis are common. We recently reported that hepatic PPARα protein is profoundly depleted in male mice undernourished by a low-protein, low-fat diet. Here, we identify PPARα as a deacetylation target of the NAD-dependent deacetylase sirtuin-1 (SIRT1) and link this to the decrease in PPARα protein levels in undernourished liver. Livers from undernourished male mice expressed high levels of SIRT1, with decreased PPARα acetylation and strongly decreased hepatic PPARα protein. In cultured hepatocytes, PPARα protein levels were decreased by transiently transfecting constitutively active SIRT1 or by treating cells with the potent SIRT1 activator resveratrol, while silencing SIRT1 increased PPARα protein levels. SIRT1 expression is correlated with increased PPARα ubiquitination, suggesting that protein loss is due to proteasomal degradation. In accord with these findings, the dramatic loss of hepatic PPARα in undernourished male mice was completely restored by treating mice with the proteasome inhibitor bortezomib. Similarly, treating undernourished mice with the SIRT1 inhibitor selisistat/EX-527 completely restored hepatic PPARα protein. These data suggest that induction of SIRT1 in undernutrition results in hepatic PPARα deacetylation, ubiquitination, and degradation, highlighting a new mechanism that mediates the liver's failed adaptive metabolic responses in chronic undernutrition.

Brain Derived Neurotrophic Factor Deficiency is Associated with Cognitive Impairment and Elevated Phospholipase A2 Activity in Plasma of Mice

Decreased levels of Brain-Derived Neurotrophic Factor (BDNF) are a common finding in schizophrenia. Another well-documented protein linked to schizophrenia is intracellular Ca²⁺-independent Phospholipase (PLA2). However, the potential association between PLA2 and BDNF with regard to schizophrenia has yet to be examined. In the present study, male and female BDNF knockout mice, a possible genetic model of schizophrenia, were exposed to prenatal stress and tested in the nest test, open field test and T-maze. Following behavioral tests, whole brain and plasma samples were harvested to measure the activity of PLA2. BDNF knockout mice showed cognitive deficits in the T-maze. Furthermore, there was a quadratic association of PLA2 with performance in the open field test. Moreover, BDNF deficiency and female sex were associated with elevated plasma PLA2 levels. The cognitive impairment of BDNF heterozygous mice as well as their increased PLA2 activity in plasma is consistent with findings in schizophrenia patients. The particular elevation of PLA2 activity in females may partly explain sex differences of clinical symptoms in schizophrenia (e.g. age of onset, severity of symptoms). Additionally, PLA2 was significantly correlated with body and adrenal weight after weaning, whereby the latter emphasizes the possible connection of PLA2 with steroidogenesis.

The review of alpha-linolenic acid: Sources, metabolism, and pharmacology

α-linolenic acid (ALA, 18:3n-3) is a carboxylic acid composed of 18 carbon atoms and three cis double bonds, and is an essential fatty acid indispensable to the human body. This study aims to systematically review related studies on the dietary sources, metabolism, and pharmacological effects of ALA. Information on ALA was collected from the internet database PubMed, Elsevier, ResearchGate, Web of Science, Wiley Online Library, and Europe PMC using a combination of keywords including "pharmacology," "metabolism," "sources." The following findings are mainly contained. (a) ALA can only be ingested from food and then converted into eicosapentaenoic acid and docosahexaenoic acid in the body. (b) This conversion process is relatively limited and affected by many factors such as dose, gender, and disease. (c) Pharmacological research shows that ALA has the anti-metabolic syndrome, anticancer, antiinflammatory, anti-oxidant, anti-obesity, neuroprotection, and regulation of the intestinal flora properties. (d) There are the most studies that prove ALA has anti-metabolic syndrome effects, including experimental studies and clinical trials. (e) The therapeutic effect of ALA will be affected by the dosage. In short, ALA is expected to treat many diseases, but further high quality studies are needed to firmly establish the clinical efficacy of ALA.

Sex Differences in Pulmonary Eicosanoids and Specialized Pro-Resolving Mediators in Response to Ozone Exposure

Ozone (O3) is a criteria air pollutant known to increase the morbidity and mortality of cardiopulmonary diseases. This occurs through a pulmonary inflammatory response characterized by increased recruitment of immune cells into the airspace, pro-inflammatory cytokines, and pro-inflammatory lipid mediators. Recent evidence has demonstrated sex-dependent differences in the O3-induced pulmonary inflammatory response. However, it is unknown if this dimorphic response is evident in pulmonary lipid mediator metabolism. We hypothesized that there are sex-dependent differences in lipid mediator production following acute O3 exposure. Male and female C57BL/6J mice were exposed to 1 part per million O3 for 3 hours and were necropsied at 6 or 24 hours following exposure. Lung lavage was collected for cell differential and total protein analysis, and lung tissue was collected for mRNA analysis, metabololipidomics, and immunohistochemistry. Compared to males, O3-exposed female mice had increases in airspace neutrophilia, neutrophil chemokine mRNA, pro-inflammatory eicosanoids such as prostaglandin E2, and specialized pro-resolving mediators (SPMs) such as resolvin D5 in lung tissue. Likewise, precursor fatty acids (arachidonic and docosahexaenoic acid; DHA) were increased in female lung tissue following O3 exposure compared to males. Experiments with ovariectomized females revealed that loss of ovarian hormones exacerbates pulmonary inflammation and injury. However, eicosanoid and SPM production were not altered by ovariectomy despite depleted pulmonary DHA concentrations. Taken together, these data indicate that O3 drives an increased pulmonary inflammatory and bioactive lipid mediator response in females. Furthermore, ovariectomy increases susceptibility to O3-induced pulmonary inflammation and injury, as well as decreases pulmonary DHA concentrations.

Higher Increase in Plasma DHA in Females Compared to Males Following EPA Supplementation May Be Influenced by a Polymorphism in ELOVL2: An Exploratory Study

Young adult females have higher blood docosahexaenoic acid (DHA), 22:6n-3 levels than males, and this is believed to be due to higher DHA synthesis rates, although DHA may also accumulate due to a longer half-life or a combination of both. However, sex differences in blood fatty acid responses to eicosapentaenoic acid (EPA), 20:5n-3 or DHA supplementation have not been fully investigated. In this exploratory analysis, females and males (n = 14-15 per group) were supplemented with 3 g/day EPA, 3 g/day DHA, or olive oil control for 12 weeks. Plasma was analyzed for sex effects at baseline and changes following 12 weeks' supplementation for fatty acid levels and carbon-13 signature (δ¹³ C). Following EPA supplementation, the increase in plasma DHA in females (+23.8 ± 11.8, nmol/mL ± SEM) was higher than males (-13.8 ± 9.2, p < 0.01). The increase in plasma δ¹³ C-DHA of females (+2.79 ± 0.31, milliUrey (mUr ± SEM) compared with males (+1.88 ± 0.44) did not reach statistical significance (p = 0.10). The sex effect appears driven largely by increased plasma DHA in the AA genotype of females (+58.8 ± 11.5, nmol/mL ± SEM, n = 5) compared to GA + GG in females (+4.34 ± 13.5, n = 9) and AA in males (-29.1 ± 17.2, n = 6) for rs953413 in the ELOVL2 gene (p < 0.001). In conclusion, EPA supplementation increases plasma DHA levels in females compared to males, which may be dependent on the AA genotype for rs953413 in ELOVL2.

Time Course and Sex Effects of α-Linolenic Acid-Rich and DHA-Rich Supplements on Human Plasma Oxylipins: A Randomized Double-Blind Crossover Trial

BACKGROUND

Differences in health effects of dietary α-linolenic acid (ALA) and DHA are mediated at least in part by differences in their effects on oxylipins.

OBJECTIVES

Time course and sex differences of plasma oxylipins in response to ALA- compared with DHA-rich supplements were examined.

METHODS

Healthy men and women, aged 19-34 y and BMI 18-28 kg/m2, were provided with capsules containing ∼4 g/d of ALA or DHA in a randomized double-blind crossover study with >6-wk wash-in and wash-out phases. Plasma PUFA and oxylipin (primary outcome) concentrations at days 0, 1, 3, 7, 14, and 28 of supplementation were analyzed by GC and HPLC-MS/MS, respectively. Sex differences, supplementation and time effects, and days to plateau were analyzed.

RESULTS

ALA supplementation doubled ALA concentrations, but had no effects on ALA oxylipins after 28 d, whereas DHA supplementation tripled both DHA and its oxylipins. Increases in DHA oxylipins were detected as early as day 1, and a plateau was reached by days 5-7 for 11 of 12 individual DHA oxylipins and for total DHA oxylipins. Nine individual DHA oxylipins reached a plateau in females with DHA supplementation, compared with only 4 in males. A similar time course and sex difference pattern occurred with EPA and its oxylipins with DHA supplementation. DHA compared with ALA supplementation also resulted in higher concentrations of 4 individual arachidonic acids, 1 linoleic acid, and 1 dihomo-γ-linolenic acid oxylipin, despite not increasing the concentrations of these fatty acids, further demonstrating that oxylipins do not always reflect their precursor PUFA.

CONCLUSIONS

DHA compared with a similar dose of ALA has greater effects on both n-3 and n-6 oxylipins in young, healthy adults, with differences in response to DHA supplementation occurring earlier and being greater in females. These findings can help explain differences in dietary effects of ALA and DHA.This study was registered at clinicaltrials.gov as NCT02317588.

Gender-Specific Beneficial Effects of Docosahexaenoic Acid Dietary Supplementation in G93A-SOD1 Amyotrophic Lateral Sclerosis Mice

Docosahexaenoic acid (DHA) is an essential fatty acid modulating key nervous system functions, including neuroinflammation, and regulation of pre- and postsynaptic membrane formation. DHA concentration decreases in the lumbar spinal cord (LSC) of amyotrophic lateral sclerosis (ALS) patients and murine preclinical models. Using a dietary supplementation, we increased DHA levels (2% mean increase, p < 0.01) in the LSC of the familial ALS murine model B6SJL-Tg(SOD1*G93A)1Gur/J. This DHA-enriched diet significantly increases male mouse survival by 7% (average 10 days over 130 days of life expectancy), and delays motor dysfunction (based on stride length) and transgene-associated weight loss (p < 0.01). DHA supplementation led to an increased anti-inflammatory fatty acid profile (ca 30%, p < 0.01) and a lower concentration of circulating proinflammatory cytokine TNF-α (p < 0.001 in males). Furthermore, although DHA-treated mice did not exhibit generally decreased protein oxidative markers (glutamic and aminoadipic semialdehydes, carboxyethyllysine, carboxymethyllysine, and malondialdehydelysine), dietary intake of DHA reduced immunoreactivity towards DNA oxidative damage markers (8-oxo-dG) in the LSC. In vitro we demonstrate that DHA and α-tocopherol addition to a model of motor neuron demise (neonatal rat organotypic spinal cord model under chronic excitotoxicity) also preserves motor neuron number, in comparison with untreated spinal cords. Also, beneficial effects on cell viability were evidenced for the motor neuron cell line NSC-34 in front of H2O2 insult (p < 0.001). Globally we show a sex-specific benefit of dietary DHA supplementation in the G93A ALS mouse model, compared with mice fed an isocaloric control or a n-3-depleted diet. These changes were associated with an increased DHA concentration in the LSC and were compatible with in vitro results showing DHA neuroprotective properties. These results suggest the need for further study on the interaction of gender-influenced biological parameters and DHA in ALS pathogenesis.

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.

Evaluation of a Rapid Assessment Questionnaire Using a Biomarker for Dietary Intake of n-3 Fatty Acids

While there is considerable evidence supporting health benefits of consuming diets high in omega-3 (n-3) fatty acids, there is no quick and effective tool to measure n-3 intake. The objective of this study was to evaluate the accuracy of a rapid assessment questionnaire (the Omega-3 Checklist) used to quantify intake of n-3 fatty acids. This was done by comparing n-3 intakes to blood biomarkers of n-3 exposure in a population of healthy men and women. In addition, a separate analysis was run including covariates age, sex, and weight, which have been shown to affect n-3 biomarker levels. Reported intake of eicosapentaenoic acid (EPA), docoshexaenoic acid (DHA), and EPA + DHA was correlated with erythrocyte EPA (Spearman's rank correlation r_s  = 0.51, p < 0.001), DHA (r_s  = 0.54, p < 0.001), and the Omega-3 Index (r_s  = 0.57, p < 0.001). These associations remained significant when controlling for age, sex, and weight. Therefore, the Omega-3 Checklist can be a useful, rapid assessment tool to estimate individuals' EPA and DHA intake.

Maternal dietary calcium status during pregnancy and lactation affects brain DHA accretion through modifying DNA methylation of fatty acid desaturases in the mouse offspring

Disturbed calcium homeostasis has detrimental effects on brain development and function, particularly in early life because of epigenetic determination of early nutrition on later health. We hypothesized that the imbalance of calcium status in early life might have long-lasting effects on brain DHA accretion though epigenetic modification on fatty acid desaturases (Fads). Three to four week old C57BL/6J female mice were fed 3 reproductive diets with different calcium concentrations - low (LC, 0.25%), normal (NC, 0.70%) and high-calcium (HC, 1.20%) respectively throughout pregnancy and lactation. Maternal LC diet reduced tissue (brain and hepatic) DHA concentrations in both male and female offsprings at postnatal 21 day, with reductions in male instead of female offsprings in adulthood. Maternal HC diet only reduced hepatic DHA concentration in adult male offsprings. Furthermore, maternal LC diet reduced hepatic but increased brain expressions of Fads1 or Fads2 in 21-days old offsprings, with similar changes in adult male instead of female offsprings. Maternal HC diet reduced hepatic or brain expressions of Fads1 or Fads2 in 21-days old offsprings, and only reduced Fads2 in the liver with adult male offsprings. Determination of DNA methylation (CpG4, CpG5, CpG7,8, CpG14-17 and CpG19) showed that maternal LC diet caused hypermethylation of Fads2 promoter in the liver and hypomethylation in the brain in 21-days old offsprings, as well as in adult male offsprings. These data demonstrate that the imbalance of calcium intake in early life might have long-term gender-specific effects on brain accretion of DHA mediated by altered DNA methylation and associated expressions of Fads.

Screening dietary biochanin A, daidzein, equol and genistein for their potential to increase DHA biosynthesis in rainbow trout (Oncorhynchus mykiss)

Plant oil utilization in aquafeeds is still the most practical option, although it decreases the content of the nutritionally highly valuable omega-3 fatty acids eicosapentaenoic acid (20:5n-3, EPA) and docosahexaenoic acid (22:6n-3, DHA) in fish. Phytoestrogens and their metabolites are putatively able to affect genes encoding proteins centrally involved in the biosynthesis of EPA and DHA due to their estrogenic potential. Thus, the aim of the study was to screen the potential of the phytoestrogens to stimulate the biosynthesis of EPA and DHA in rainbow trout (Oncorhynchus mykiss). Additionally, the potential effects on growth performance, nutrient composition and hepatic lipid metabolism in rainbow trout were investigated. For that, a vegetable oil based diet served as a control diet (C) and was supplemented with 15 g/kg dry matter of biochanin A (BA), daidzein (DA), genistein (G) and equol (EQ), respectively. These five diets were fed to rainbow trout (initial body weight 83.3 ± 0.4 g) for 52 days. Growth performance and nutrient composition of whole body homogenates were not affected by the dietary treatments. Furthermore, feeding EQ to rainbow trout significantly increased DHA levels by +8% in whole body homogenates compared to samples of fish fed the diet C. A tendency towards increased DHA levels in whole body homogenates was found for fish fed the diet G. Fish fed diets BA and DA lacked these effects. Moreover, EQ and G fed fish showed significantly decreased hepatic mRNA steady state levels for fatty acyl desaturase 2a (delta-6) (fads2a(d6)). In contrast, carnitine palmitoyl transferases 1 (cpt1) hepatic mRNA steady state levels and hepatic Fads2a(d6) protein contents were not affected by the dietary treatment. In conclusion, when combined with dietary vegetable oils, equol and genistein seem to stimulate the biosynthesis of DHA and thereby increase tissue DHA levels in rainbow trout, however, only to a moderate extent.

Low-linoleic acid diet and oestrogen enhance the conversion of α-linolenic acid into DHA through modification of conversion enzymes and transcription factors

Conversion of α-linolenic acid (ALA) into the longer chain n-3 PUFA has been suggested to be affected by the dietary intake of linoleic acid (LA), but the mechanism is not well known. Therefore, the purpose of this study was to evaluate the effect of a low-LA diet with and without oestrogen on the fatty acid conversion enzymes and transcription factors. Rats were fed a modified American Institute of Nutrition-93G diet with 0% n-3 PUFA or ALA, containing low or high amounts of LA for 12 weeks. At 8 weeks, the rats were injected with maize oil with or without 17β-oestradiol-3-benzoate (E) at constant intervals for the remaining 3 weeks. Both the low-LA diet and E significantly increased the hepatic expressions of PPAR-α, fatty acid desaturase (FADS) 2, elongase of very long chain fatty acids 2 (ELOVL2) and ELOVL5 but decreased sterol regulatory element binding protein 1. The low-LA diet, but not E, increased the hepatic expression of FADS1, and E increased the hepatic expression of oestrogen receptor-α and β. The low-LA diet and E had synergic effects on serum and liver levels of DHA and on the hepatic expression of PPAR-α. In conclusion, the low-LA diet and oestrogen increased the conversion of ALA into DHA by upregulating the elongases and desaturases of fatty acids through regulating the expression of transcription factors. The low-LA diet and E had a synergic effect on serum and liver levels of DHA through increasing the expression of PPAR-α.

Science behind the cardio-metabolic benefits of omega-3 polyunsaturated fatty acids: biochemical effects vs. clinical outcomes

Lower incidence of cardiovascular disease (CVD) in the Greenland Inuit, Northern Canada and Japan has been attributed to their consumption of seafood rich in long chain omega-3 polyunsaturated fatty acids (LCn-3PUFA). While a large majority of pre-clinical and intervention trials have demonstrated heart health benefits of LCn-3PUFA, some studies have shown no effects or even negative effects. LCn-3PUFA have been shown to favourably modulate blood lipid levels, particularly a reduction in circulating levels of triglycerides. High density lipoprotein-cholesterol (HDL-C) levels are elevated following dietary supplementation with LCn-3PUFA. Although LCn-3PUFA have been shown to increase low-density lipoprotein-cholesterol (LDL-C) levels, the increase is primarily in the large-buoyant particles that are less atherogenic than small-dense LDL particles. The anti-inflammatory effects of LCn-3PUFA have been clearly outlined with inhibition of NFkB mediated cytokine production being the main mechanism. In addition, reduction in adhesion molecules (intercellular adhesion molecule, ICAM and vascular cell adhesion molecule 1, VCAM-1) and leukotriene production have also been demonstrated following LCn-3PUFA supplementation. Anti-aggregatory effects of LCn-3PUFA have been a subject of controversy, however, recent studies showing sex-specific effects on platelet aggregation have helped resolve the effects on hyperactive platelets. Improvements in endothelium function, blood flow and blood pressure after LCn-3PUFA supplementation add to the mechanistic explanation on their cardio-protective effects. Modulation of adipose tissue secretions including pro-inflammatory mediators and adipokines by LCn-3PUFA has re-ignited interest in their cardiovascular health benefits. The aim of this narrative review is to filter out the reasons for possible disparity between cohort, mechanistic, pre-clinical and clinical studies. The focus of the article is to provide possible explanation for the observed controversies surrounding heart health benefits of LCn-3PUFA.

Impact of Dietary Fats on Brain Functions

BACKGROUND

Adequate dietary intake and nutritional status have important effects on brain functions and on brain health. Energy intake and specific nutrients excess or deficiency from diet differently affect cognitive processes, emotions, behaviour, neuroendocrine functions and synaptic plasticity with possible protective or detrimental effects on neuronal physiology. Lipids, in particular, play structural and functional roles in neurons. Here the importance of dietary fats and the need to understand the brain mechanisms activated by peripheral and central metabolic sensors. Thus, the manipulation of lifestyle factors such as dietary interventions may represent a successful therapeutic approach to maintain and preserve brain health along lifespan.

METHODS

This review aims at summarizing the impact of dietary fats on brain functions.

RESULTS

Starting from fat consumption, nutrient sensing and food-related reward, the impact of gut-brain communications will be discussed in brain health and disease. A specific focus will be on the impact of fats on the molecular pathways within the hypothalamus involved in the control of reproduction via the expression and the release of Gonadotropin-Releasing Hormone. Lastly, the effects of specific lipid classes such as polyunsaturated fatty acids and of the "fattest" of all diets, commonly known as "ketogenic diets", on brain functions will also be discussed.

CONCLUSION

Despite the knowledge of the molecular mechanisms is still a work in progress, the clinical relevance of the manipulation of dietary fats is well acknowledged and such manipulations are in fact currently in use for the treatment of brain diseases.

Validation of repeated self-reported n-3 PUFA intake using serum phospholipid fatty acids as a biomarker in breast cancer patients during treatment

Background

The role of n-3 polyunsaturated fatty acids (PUFAs) in breast cancer is not clear and under debate. To explore this relationship it is important to have proper validated dietary assessment methods for measuring the intake of n-3 PUFAs. The aim of the current study is to validate two different methods used to assess the intake of selected n-3 PUFAs as well as food sources of long-chained n-3 PUFAs. Also, we aim to study how stable the intake of fatty acids is during breast cancer treatment.

Methods

The study-population was patients with breast cancer (Stages I-II) or ductal carcinoma in situ (DCIS-grade III) undergoing treatment (n = 49) in Norway. Dietary intake was assessed by two self-administered methods, a 256 food item food frequency questionnaire (FFQ) and a 7-day pre-coded food diary (PFD). The FFQ was administered presurgery and twelve months postsurgery, and the PFD was administered shortly after surgery (10 +/− 2 days), six and twelve months postsurgery. Fasting blood samples (presurgery, six and twelve months postsurgery) were analysed for serum phospholipid fatty acids, a biomarker for intake of n-3 PUFAs.

Results

Mean (SD) age was 54.2 (7.8) years at diagnosis, and the mean (SD) body mass index (BMI) was 24.8 (3.4) kg/m². Correlation coefficients between dietary intakes of n-3 PUFAs measured with the FFQ and the PFD ranged from 0.35 to 0.66. The correlation coefficients between the PFD and the biomarker (serum phospholipid n-3 PUFAs) as well as between the FFQ and the biomarker demonstrated stronger correlations twelve months after surgery (ρ 0.40–0.56 and 0.36–0.53, respectively) compared to around surgery (ρ 0.08–0.20 and 0.28–0.38, respectively). The same pattern was observed for intake of fatty fish. The intake of n-3 PUFAs did not change during treatment assessed by the FFQ, PFD or biomarker.

Conclusion

These results indicate that the FFQ and the PFD can be used to assess dietary intake of fish and n-3 PUFAs in breast cancer patients during breast cancer treatment. Still, the PFD shortly after surgery should be used with caution. The diet of patients undergoing breast cancer treatment was quite stable, and the intake of n-3 PUFAs did not change.

Electronic supplementary material

The online version of this article (10.1186/s12937-018-0402-6) contains supplementary material, which is available to authorized users.

An association between the BanI polymorphism of the PLA2G4A gene for calcium-dependent phospholipase A2 and plasma glucose levels among females with schizophrenia

Abnormal glucose and lipid metabolism may be associated with altered cytosolic Ca²⁺-dependent phospholipase A2 (cPLA2) signaling in patients with schizophrenia. The relationship between schizophrenia and the functional BanI polymorphism (rs10798059 variant, A/G polymorphism) of the PLA2G4A gene for cPLA2 has been extensively investigated. We previously reported that it can influence several clinical features of schizophrenia, and it was shown to contribute to schizophrenia risk in several population studies. We performed PCR/RFLP genotyping of 263 Croatian patients (males/females: 139/124) to investigate the relationship between the BanI polymorphism and fasting plasma glucose and lipid levels in patients with schizophrenia. Our results indicate that the BanI polymorphic variant contributes significantly to plasma glucose levels in female patients. Females carrying the PLA2G4A-G allele (PLA2G4A-GG homozygous and PLA2G4A-AG heterozygous) presented with lower glucose levels than PLA2G4A-AA homozygous carriers, and the PLA2G4A genotype contributed approximately 6% of plasma glucose level variability in this group of patients.

Food for thought: how nutrition impacts cognition and emotion

More than one-third of American adults are obese and statistics are similar worldwide. Caloric intake and diet composition have large and lasting effects on cognition and emotion, especially during critical periods in development, but the neural mechanisms for these effects are not well understood. A clear understanding of the cognitive-emotional processes underpinning desires to over-consume foods can assist more effective prevention and treatments of obesity. This review addresses recent work linking dietary fat intake and omega-3 polyunsaturated fatty acid dietary imbalance with inflammation in developing, adult, and aged brains. Thus, early-life diet and exposure to stress can lead to cognitive dysfunction throughout life and there is potential for early nutritional interventions (e.g., with essential micronutrients) for preventing these deficits. Likewise, acute consumption of a high-fat diet primes the hippocampus to produce a potentiated neuroinflammatory response to a mild immune challenge, causing memory deficits. Low dietary intake of omega-3 polyunsaturated fatty acids can also contribute to depression through its effects on endocannabinoid and inflammatory pathways in specific brain regions leading to synaptic phagocytosis by microglia in the hippocampus, contributing to memory loss. However, encouragingly, consumption of fruits and vegetables high in polyphenolics can prevent and even reverse age-related cognitive deficits by lowering oxidative stress and inflammation. Understanding relationships between diet, cognition, and emotion is necessary to uncover mechanisms involved in and strategies to prevent or attenuate comorbid neurological conditions in obese individuals.

PEMT, Δ6 desaturase, and palmitoyldocosahexaenoyl phosphatidylcholine are increased in rats during pregnancy

DHA is important for fetal neurodevelopment. During pregnancy, maternal plasma DHA increases, but the mechanism is not fully understood. Using rats fed a fixed-formula diet (DHA as 0.07% total energy), plasma and liver were collected for fatty acid profiling before pregnancy, at 15 and 20 days of pregnancy, and 7 days postpartum. Phosphatidylethanolamine methyltransferase (PEMT) and enzymes involved in PUFA synthesis were examined in liver. Ad hoc transcriptomic and lipidomic analyses were also performed. With pregnancy, DHA increased in liver and plasma lipids, with a large increase in plasma DHA between day 15 and day 20 that was mainly attributed to an increase in 16:0/DHA phosphatidylcholine (PC) in liver (2.6-fold) and plasma (3.9-fold). Increased protein levels of Δ6 desaturase (FADS2) and PEMT at day 20 and increased Pemt expression and PEMT activity at day 15 suggest that during pregnancy, both DHA synthesis and 16:0/DHA PC synthesis are upregulated. Transcriptomic analysis revealed minor changes in the expression of genes related to phospholipid synthesis, but little insight on DHA metabolism. Hepatic PEMT appears to be the mechanism for increased plasma 16:0/DHA PC, which is supported by increased DHA biosynthesis based on increased FADS2 protein levels.

Sexual dimorphism in hepatic lipids is associated with the evolution of metabolic status in mice

Ectopic lipid accumulation in the liver is implicated in metabolic disease in an age- and sex-dependent manner. The role of hepatic lipids has been well established within the scope of metabolic insults in mice, but has been insufficiently characterized under standard housing conditions, where age-related metabolic alterations are known to occur. We studied a total of 10 male and 10 female mice longitudinally. At 3, 7 and 11 months of age, non-invasive ¹ H-magnetic resonance spectroscopy (¹ H-MRS) was used to monitor hepatic lipid content (HLC) and fatty acid composition in vivo, and glucose homeostasis was assessed with glucose and insulin challenges. At the end of the study, hepatic lipids were comprehensively characterized by nuclear magnetic resonance (NMR) and liquid chromatography-mass spectrometric analyses of liver tissue samples. In males, HLC increased from 1.4 ± 0.1% at 3 months to 2.9 ± 0.3% at 7 months (p < 0.01) and 2.7 ± 0.3% at 11 months (p < 0.05), in correlation with fasting insulin levels (p < 0.01, r = 0.51) and parameters from the insulin tolerance test (ITT; p < 0.001, r = -0.69 versus area under the curve; p < 0.01, r = -0.57 versus blood glucose drop at 1 h post-ITT; p < 0.01, r = 0.55 versus blood glucose at 3 h post-ITT). The metabolic performance of females remained the same throughout the study, and HLC was higher than that of males at 3 months (2.7 ± 0.2%, p < 0.01), but comparable at 7 months (2.2 ± 0.2%) and 11 months (2.2 ± 0.1%). Strong sexual dimorphism in bioactive lipid species, including diacylglycerols (higher in males, p < 0.0001), phosphatidylinositols (higher in females, p < 0.001) and omega-3 polyunsaturated fatty acids (higher in females, p < 0.01), was found to be in good correlation with metabolic scores at 11 months. Therefore, in mice housed under standard conditions, sex-specific composition of bioactive lipids is associated with metabolic protection in females, whose metabolic performance was independent of hepatic cytosolic lipid content.

Effects of the flavonol quercetin and α-linolenic acid on n-3 PUFA status in metabolically healthy men and women: a randomised, double-blinded, placebo-controlled, crossover trial

Increased dietary intake and tissue status of the long-chain n-3 PUFA, EPA and DHA, is associated with cardiovascular benefits. Epidemiological and animal studies suggest that concomitant nutritive intake of flavonoids may increase the conversion of α-linolenic acid (ALA) to longer-chain n-3 fatty acids EPA and DHA. We investigated the effects of increased ALA intake on fatty acid composition of serum phospholipids and erythrocytes in metabolically healthy men and women and whether fatty acid profiles and ALA conversion were affected by regular quercetin intake or sex. Subjects (n 74) were randomised to receive at least 3·3 g/d ALA with either 190 mg/d quercetin (ALA+quercetin) or placebo (ALA+placebo) in a double-blinded, placebo-controlled, crossover trial with 8-week intervention periods separated by an 8-week washout period. A total of seven subjects dropped out for personal reasons. Data from the remaining sixty-seven subjects (thirty-four males and thirty-three females) were included in the analysis. Both interventions significantly increased serum phospholipid ALA (ALA+placebo: +69·3 %; ALA+quercetin: +55·8 %) and EPA (ALA+placebo: +37·3 %; ALA+quercetin: +25·5 %). ALA + quercetin slightly decreased DHA concentration by 9·3 %. Erythrocyte ALA and EPA significantly increased with both interventions, whereas DHA decreased. Fatty acid composition did not differ between sexes. We found no effect of quercetin. Intake of 3·6 g/d ALA over an 8-week period resulted in increased ALA and EPA, but not DHA, in serum phospholipids and erythrocytes. Neither quercetin supplementation nor sex affected the increment of ALA and relative proportions of n-3 PUFA in serum phospholipids and erythrocytes.

Maternal fish oil supplementation during lactation is associated with reduced height at 13 years of age and higher blood pressure in boys only

Dietary long-chain n-3 PUFA (n-3 LCPUFA) in infancy may have long-term effects on lifestyle disease risk. The present follow-up study investigated whether maternal fish oil (FO) supplementation during lactation affected growth and blood pressure in adolescents and whether the effects differed between boys and girls. Mother-infant pairs (n 103) completed a randomised controlled trial with FO (1·5 g/d n-3 LCPUFA) or olive oil (OO) supplements during the first 4 months of lactation; forty-seven mother-infant pairs with high fish intake were followed-up for 4 months as the reference group. We also followed-up 100 children with assessment of growth, blood pressure, diet by FFQ and physical activity by 7-d accelerometry at 13·5 (sd 0·4) years of age. Dried whole-blood fatty acid composition was analysed in a subgroup (n 49). At 13 years of age, whole-blood n-3 LCPUFA, diet, physical activity and body composition did not differ between the three groups. The children from the FO group were 3·4 (95 % CI 0·2, 6·6) cm shorter (P=0·035) than those from the OO group, and tended to have less advanced puberty (P=0·068), which explained the difference in height. There was a sex-specific effect on diastolic blood pressure (P sex×group=0·020), which was driven by a 3·9 (95 % CI 0·2, 7·5) mmHg higher diastolic blood pressure in the FO compared with the OO group among boys only (P=0·041). Our results indicate that early n-3 LCPUFA intake may reduce height in early adolescence due to a delay in pubertal maturation and increase blood pressure specifically in boys, thereby tending to counteract existing sex differences.

Do sex hormones or hormone therapy modify the relation of n-3 fatty acids with incident depressive symptoms in postmenopausal women? The MESA Study

INTRODUCTION

Considering that estradiol (E2) and n-3 polyunsaturated fatty acids (PUFAs) have roles in neurogenesis and in neurotransmission, we examined whether the association of PUFAs with incident depressive symptoms in postmenopausal women is modified by hormone therapy (HT) use or estrogen status.

METHODS

Women (N=1616) free of depressive symptoms at baseline (2000-2002) in the Multi-Ethnic Study of Atherosclerosis were classified by HT usage and quartiles of dietary eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and the sum EPA+DHA. Women with serum E2 ≤0.073 nmol/L (sample median), were classified low on E2. Poisson regression was used to model incident depressive symptoms at examination 3 (2004-05), defined by the Center for Epidemiological Studies Depression Scale ≥16 or taking an antidepressant, first as a function of HT use and n-3 PUFA quartiles, and second, as a function of low E2 status and n-3 PUFA quartiles.

RESULTS

Among HT non- users, positive, graded relationships (p-trends≤0.003) were found between PUFAs and incident depressive symptoms. Compared to the lowest quartile, the adjusted risk ratios (RRs) for the highest were 2.10, 2.39, and 2.04 for EPA, DHA, and EPA+DHA, respectively. For HT users, no associations were seen. When analyses were run for E2 status, the RRs over quartiles of the PUFAs were positive and graded for low E2 women, but were null for High E2 women.

CONCLUSIONS

Higher intakes of DHA and EPA were associated with higher risk of depressive symptoms in nonusers of HT, contrary to hypothesis.

Role of n-3 Polyunsaturated Fatty Acids in Ameliorating the Obesity-Induced Metabolic Syndrome in Animal Models and Humans

The incidence of obesity and its comorbidities, such as insulin resistance and type II diabetes, are increasing dramatically, perhaps caused by the change in the fatty acid composition of common human diets. Adipose tissue plays a role as the major energy reservoir in the body. An excess of adipose mass accumulation caused by chronic positive energy balance results in obesity. The n-3 polyunsaturated fatty acids (n-3 PUFA), DHA (docosahexaenoic acid) and EPA (eicosapentaenoic acid) exert numerous beneficial effects to maintain physiological homeostasis. In the current review, the physiology of n-3 PUFA effects in the body is delineated from studies conducted in both human and animal experiments. Although mechanistic studies in human are limited, numerous studies conducted in animals and models in vitro provide potential molecular mechanisms of the effects of these fatty acids. Three aspects of n-3 PUFA in adipocyte regulation are discussed: (1) lipid metabolism, including adipocyte differentiation, lipolysis and lipogenesis; (2) energy expenditure, such as mitochondrial and peroxisomal fatty acid β-oxidation; and (3) inflammation, including adipokines and specialized pro-resolving lipid mediators. Additionally, the mechanisms by which n-3 PUFA regulate gene expression are highlighted. The beneficial effects of n-3 PUFA may help to reduce the incidence of obesity and its comorbidities.

An association between the PPARα-L162V polymorphism and nicotine dependency among patients with schizophrenia

OBJECTIVE

Patients with schizophrenia are more likely to be smokers than the general population, which makes them an interesting group with which to study the etiology of nicotine dependency. We studied the prevalence of a gene variant of peroxisome proliferator-activated receptor alpha (PPARα) in schizophrenia, together with nicotine dependency, to investigate whether the PPARα-L162V polymorphism (rs1800206) influences nicotine dependency in schizophrenia. Given evidence suggesting that smoking influences the severity of schizophrenia, together with our recent data linking the PPARα-L162V polymorphism to clinical manifestations of schizophrenia (in the Croatian population), we hypothesized that interactions between the two (smoking and the PPARα-L162V polymorphism) might contribute to disease onset and scores for the Positive and Negative Syndrome Scale. To the best of our knowledge, this is the first study to investigate the possible associations between the PPARα gene and nicotine dependency.

PATIENTS AND METHODS

Genotyping was performed for 267 chronically ill schizophrenia patients (males/females: 140/127) by polymerase chain reaction.

RESULTS

A significant excess of PPARα-L162V genotypes and PPARα-162V alleles were detected among female smokers in comparison to female nonsmokers (18.2% vs. 2.0%, and 9.1% vs. 1.0%, p<0.01, respectively). We also revealed a significant PPARα genotype-smoking interaction that predicted positive symptom severity among male patients (F=4.43, p<0.05). These data indicated that the PPARα-L162V heterozygous genotype, depending on smoking status, might be of relevance as either protective, or a risk factor, for the severity of positive symptoms. No interaction between the PPARα-L162V polymorphism and smoking for the time of onset of schizophrenia was detected (p>0.05, respectively).

CONCLUSION

We demonstrated two significant yet weak effects. The first showed an effect of the PPARα-L162V polymorphism on the risk of nicotine dependency. The second linked the PPARα genotype-smoking interaction to positive symptoms severity among schizophrenia patients; both effects manifested in a gender-specific fashion.

Sexually dimorphic brain fatty acid composition in low and high fat diet-fed mice

OBJECTIVE

In this study, we analyzed the fatty acid profile of brains and plasma from male and female mice fed chow or a western-style high fat diet (WD) for 16 weeks to determine if males and females process fatty acids differently. Based on the differences in fatty acids observed in vivo, we performed in vitro experiments on N43 hypothalamic neuronal cells to begin to elucidate how the fatty acid milieu may impact brain inflammation.

METHODS

Using a comprehensive mass spectrometry fatty acid analysis, which includes a profile for 52 different fatty acid isomers, we assayed the plasma and brain fatty acid composition of age-matched male and female mice maintained on chow or a WD. Additionally, using the same techniques, we determined the fatty acid composition of N43 hypothalamic cells following exposure to palmitic and linoleic acid, alone or in combination.

RESULTS

Our data demonstrate there is a sexual dimorphism in brain fatty acid content both following the consumption of the chow diet, as well as the WD, with males having an increased percentage of saturated fatty acids and reductions in ω6-polyunsaturated fatty acids when compared to females. Interestingly, we did not observe a sexual dimorphism in fatty acid content in the plasma of the same mice. Furthermore, exposure of N43 cells to the ω6-PUFA linoleic acid, which is higher in female brains when compared to males, reduces palmitic acid-induced inflammation.

CONCLUSIONS

Our data suggest male and female brains, and not plasma, differ in their fatty acid profile. This is the first time, to our knowledge, lipidomic analyses has been used to directly test the hypothesis there is a sexual dimorphism in brain and plasma fatty acid composition following consumption of the chow diet, as well as following exposure to the WD.

Omega-3 polyunsaturated fatty acid blood biomarkers increase linearly in men and women after tightly controlled intakes of 0.25, 0.5, and 1 g/d of EPA + DHA

Blood levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have been related to coronary heart disease risk. Understanding the response of EPA + DHA in blood to dietary intake of EPA + DHA would facilitate the use of blood measures as markers of adherence and enable the development of dietary recommendations. The objective of this study is examine the blood response to intakes of EPA + DHA ≤1 g/d with an intervention designed for dietary adherence. It was hypothesized this relationship would be linear and that intakes of EPA + DHA <1 g/d would result in blood levels below those associated with the highest level of protection for cardiovascular events. Background EPA + DHA intake of men and women (n = 20) was determined by food frequency questionnaire and adherence was monitored by weekly fingertip blood sampling for fatty acid determinations. Participants consumed nutraceuticals to achieve intakes of 0.25 g/d and 0.5 g/d EPA + DHA for successive four-week periods. A subgroup (n = 5) had intakes of 1.0 g/d EPA + DHA for an additional 4 weeks. Fatty acid composition of whole blood, erythrocytes, and plasma phospholipids were determined at each time point. Blood levels of EPA and DHA increased linearly in these pools. A comprehensive review of the literature was used to verify the blood-intake relationship. Blood levels of long chain omega-3 polyunsaturated fatty acids reached blood levels associated with the highest levels of primary cardiac arrest reduction and sudden cardiac death risk only with intakes of 1.0 g/d of EPA + DHA. The blood biomarker response to intakes of EPA + DHA ≤1 g/d is linear in a small but highly adherent study sample and this information can assist in determining adherence in clinical studies and help identify dietary intake targets from associations between blood and disease.

Sex-specific cardiac cardiolipin remodelling after doxorubicin treatment

Background

Imbalance in lipid metabolism and membrane lipid homeostasis has been observed in numerous diseases including heart failure and cardiotoxicity. Growing evidence links phospholipid alterations especially cardiolipins (CLs) to defects in mitochondrial function and energy metabolism in heart failure. We have shown recently that doxorubicin cardiotoxicity is more severe in male than female Wistar rats. We aimed to study whether this sex specificity is linked to differences in cardiac phospholipid profiles.

Results

Adult male and female rats were injected 2 mg/kg doxorubicin weekly for 7 weeks. Cardiac phospholipid molecular species were determined by liquid chromatography coupled with mass spectrometry fragmentation (LC)/MSⁿ. Sex difference in phosphatidylethanolamine and phosphatidylcholine species containing docosahexaenoic and docosapentaenoic acyl chains was observed, females having more than males. In both sexes, doxorubicin induced an important loss of the main CL(18:2)₄, while the level of monolysocardiolipin MLCL(18:2)₃ remained stable. However, a severe remodelling appeared in treated rats with the longest CL acyl chains in doxorubicin-treated females, which might compensate for the loss of tetra-linoleoyl CL. The level of oxidized cardiolipin was not particularly increased after doxorubicin treatment. Finally, expression of genes involved in the biosynthesis of fatty acid appeared to be decreased in doxorubicin-treated males.

Conclusions

These results emphasize for the first time the cardiac remodelling in the phospholipid classes after doxorubicin treatment. These observations suggest that doxorubicin has a sex-specific impact on the heart phospholipidome especially on cardiolipin, an essential mitochondrial lipid. Further studies are needed to better understand the roles of lipids in the anthracycline cardiotoxicity and sex differences, but phospholipid cardioprotection seems a valuable new additive therapeutic strategy for anthracycline cardiotoxicity.

Electronic supplementary material

The online version of this article (doi:10.1186/s13293-015-0039-5) contains supplementary material, which is available to authorized users.

α-linolenic acid and docosahexaenoic acid, alone and combined with trastuzumab, reduce HER2-overexpressing breast cancer cell growth but differentially regulate HER2 signaling pathways

BACKGROUND

Diets rich in the n-3 fatty acid alpha-linolenic acid (ALA) have been shown to reduce breast tumor growth, enhance the effectiveness of the HER2-targeted drug trastuzumab (TRAS) and reduce HER2 signaling in mouse models. It is unclear whether this is due to direct effects of ALA or due to its long-chain n-3 fatty acids metabolites including docosahexaenoic acid (DHA).

METHODS

The ability of HER2-overexpressing BT-474 human breast cancer cells to convert ALA to long-chain n-3 fatty acids was determined by measurement of phospholipid fatty acids by gas chromatography following treatment with 100 μM ALA. The effects of 96 h treatment with ALA or DHA, at serum levels seen in mice (50-100 μM), alone and combined with TRAS (10 μg/ml), on BT-474 cell growth measured by trypan blue exclusion, apoptosis measured by flow cytometric analysis of Annexin-V/7-AAD stained cells (ALA and TRAS treatment only) and protein biomarkers HER2 signaling measured by western blot were determined.

RESULTS

ALA-treated BT-474 cells had higher phospholipid ALA but no increase in downstream n-3 metabolites including DHA. Both ALA and DHA reduced cell growth with and without TRAS. ALA had no effect on apoptosis. ALA and DHA showed opposite effects on Akt and MAPK phosphorylation; ALA increased and DHA decreased phosphorylation.

CONCLUSIONS

Together these data suggest that, while both ALA and its DHA metabolite can reduce HER2-overexpressing breast cancer growth with and without TRAS, they demonstrate for the first time that DHA is responsible for the effects of ALA-rich diets on HER2 signaling pathways.

Ethnicity, sex, FADS genetic variation, and hormonal contraceptive use influence delta-5- and delta-6-desaturase indices and plasma docosahexaenoic acid concentration in young Canadian adults: a cross-sectional study

Background

There is great interest in the relationship between polyunsaturated fatty acids and health. Yet, the combinatory effect of factors such as sex, ethnicity, genetic polymorphisms and hormonal contraceptives (HC) on the concentrations of these fatty acids is unknown. Therefore, we sought to determine the effects of FADS polymorphisms, and HC use in females, on aggregate desaturase indices (ADI), and plasma docosahexaenoic acid (DHA) concentrations in Caucasian and East Asian males and females.

Methods

Fasting plasma samples were collected from subjects (Caucasian males: 113 and females: 298; East Asian males: 98 and females: 277) from the Toronto Nutrigenomics and Health Study. Fatty acid concentrations were measured by gas chromatography. ADI were estimated by dividing concentrations of arachidonic acid by linoleic acid (n-6 ADI) and eicosapentaenoic acid (EPA) by α-linolenic acid (n-3 ADI). [DHA/EPA] desaturase index was used to determine effects of FADS2 polymorphisms and HC use on EPA conversion to DHA.

Results

In Caucasians, associations between n-6 ADI and multiple SNP (FADS1 rs174547, FADS2 rs174576, and rs174611 in males; FADS1 rs174547, FADS2 rs174570, rs174576, rs174679, rs174611, rs174593, rs174626, rs2072114, rs2845573, and rs2851682 in females) withstood multiple testing. In East Asian females, 5 SNP-n-6 ADI associations (FADS2 rs174602, rs174626, rs2072114, rs2845573, and rs2851682) withstood multiple testing. One FADS2 SNP was associated with altered [DHA/EPA] desaturase index in Caucasian females only (rs174576, p < 0.0001). HC use had a significant effect on DHA concentrations in Caucasian females only (P < 0.0001).

Conclusions

We demonstrate ethnic- and sex-specific effects of FADS polymorphisms on desaturase indices, and ethnic-specific effect of HC use on plasma DHA concentrations.

Electronic supplementary material

The online version of this article (doi:10.1186/s12986-015-0010-9) contains supplementary material, which is available to authorized users.

Effect of linseed supplementation of the gestation and lactation diets of dairy ewes on the growth performance and the intramuscular fatty acid composition of their lambs

In this study, we investigated the effects of maternal gestation and/or lactation diets supplemented with extruded linseed (rich in 18:3n-3) on growth performance and long-chain polyunsaturated faaty acid (PUFA) accumulation in muscle tissues of suckling lambs. A total of 36 dairy ewes were fed a control diet (CON) and a diet containing linseed (LIN) during the last 8 weeks of gestation and/or the first 4 weeks of lactation. The four dietary treatments consisted of the following gestation/lactation feeding treatments: CON/CON, CON/LIN, LIN/LIN or LIN/CON. The lambs born from ewes fed the aforementioned diets were reared exclusively on milk and were slaughtered at 4 weeks of age. Profiles of ewes' milk fatty acids and that of intramuscular fat (IMF) of leg muscles from lambs were determined. Compared with the CON/CON, LIN/CON offspring tended to grow slower and to have reduced cold carcass weights. Moreover, the LIN supplementation only in the prepartum period (LIN/CON) resulted in greater PUFAn-3 accumulation in the IMF compared with the CON/CON offspring due to increased 20:5n-3 (1.20 v. 0.64 mg/100 mg of total FA), 22:5n-3 (1.91 v. 1.46;) and 22:6n-3 (1.25 v. 0.89) contents, respectively. Compared with the CON/CON diet, providing LIN only during lactation (CON/LIN) caused a greater PUFAn-3 content in the IMF mainly due to a greater 18:3n-3 (1.79 v. 0.75 mg/100 g total FA) concentration. Continuous PUFAn-3 exposure, both via the maternal gestation and lactation diet, had no additive effects on PUFAn-3 accumulation in tissues. The results suggest that linseed, as an 18:3n-3 source, seems to be more efficient in increasing long-chain PUFAn-3 in fetal than in suckling lamb tissues.

PPARα-L162V polymorphism is not associated with schizophrenia risk in a Croatian population

Disturbances of lipid and glucose metabolism have been repeatedly reported in schizophrenia. A functional L162V polymorphism in peroxisome proliferator-activated receptor alpha (PPARα) gene has been extensively investigated in etiology of abnormal lipid and glucose metabolism, yet not in schizophrenia. We determined whether the schizophrenia risk was associated with L162V polymorphism and we examined the impact of L162V variant on age of onset, and data of psychopathology scores. We also hypothesized that plasma glucose and lipid concentrations in patients may be influenced by L162V polymorphism. Genotype and allele frequencies between 203 patients and 191 controls did not differ significantly. Females heterozygous for the PPARα genotype (L162V) manifested significantly lower negative symptom scores, tended toward an earlier onset, and had significantly greater triglyceride levels. The PPARα-L162V polymorphism is not associated with schizophrenia risk in Croatian population, but it impacts clinical expression of the illness and plasma lipid concentrations in female patients.

The role of FADS1/2 polymorphisms on cardiometabolic markers and fatty acid profiles in young adults consuming fish oil supplements

Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are omega-3 (n-3) fatty acids (FAs) known to influence cardiometabolic markers of health. Evidence suggests that single nucleotide polymorphisms (SNPs) in the fatty acid desaturase 1 and 2 (FADS1/2) gene cluster may influence an individual's response to n-3 FAs. This study examined the impact of a moderate daily dose of EPA and DHA fish oil supplements on cardiometabolic markers, FA levels in serum and red blood cells (RBC), and whether these endpoints were influenced by SNPs in FADS1/2. Young adults consumed fish oil supplements (1.8 g total EPA/DHA per day) for 12 weeks followed by an 8-week washout period. Serum and RBC FA profiles were analyzed every two weeks by gas chromatography. Two SNPs were genotyped: rs174537 in FADS1 and rs174576 in FADS2. Participants had significantly reduced levels of blood triglycerides (-13%) and glucose (-11%) by week 12; however, these benefits were lost during the washout period. EPA and DHA levels increased significantly in serum (+250% and +51%, respectively) and RBCs (+132% and +18%, respectively) within the first two weeks of supplementation and remained elevated throughout the 12-week period. EPA and DHA levels in RBCs only (not serum) remained significantly elevated (+37% and +24%, respectively) after the washout period. Minor allele carriers for both SNPs experienced greater increases in RBC EPA levels during supplementation; suggesting that genetic variation at this locus can influence an individual's response to fish oil supplements.

α-Linolenic acid: nutraceutical, pharmacological and toxicological evaluation

α-Linolenic acid (ALA), a carboxylic acid with 18 carbons and three cis double bonds, is an essential fatty acid needed for human health and can be acquired via regular dietary intake of foods that contain ALA or dietary supplementation of foods high in ALA, for example flaxseed. ALA has been reported to have cardiovascular-protective, anti-cancer, neuro-protective, anti-osteoporotic, anti-inflammatory, and antioxidative effects. ALA is the precursor of longer chain omega-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), but its beneficial effects on risk factors for cardiovascular diseases are still inconclusive. The recommended intake of ALA for cardiovascular health is reported to be 1.1-2.2g/day. Although there are limited toxicological data for ALA, no serious adverse effects have been reported. The evidence on an increased prostate cancer risk in association with dietary ALA is not conclusive. Based on the limited data currently available, it may be concluded that ALA may be beneficial as a nutraceutical/pharmaceutical candidate and is safe for use as a food ingredient.

Different patterns characterize Omega 6 and Omega 3 long chain polyunsaturated fatty acid levels in blood from Italian infants, children, adults and elderly

Long chain polyunsaturated fatty acids (LC-PUFA), especially the Omega 3, modulate key functions in the body. Their circulating levels are representative of their "status", and may vary at different ages. We have compared the FA status in Italian subjects from neonates to adulthood, assessed through FA analysis of blood drops from fingertips. Data from four cohorts of Italian subjects (total number 1835), have been pooled in four age-groups: neonates (4 days, n=81), children (2-9 years, n=728), adults (40-59 years, n=434) and elderly (60-79 years, n=592). LC-PUFA of both series (Omega 3 and 6) are higher in the blood of neonates than at subsequent ages, reflecting the efficient transfer of these FA from mothers to the fetus. In contrast, the lowest levels of Omega 3 PUFA, especially of DHA, are found in children, probably reflecting inadequate dietary intakes, with possible consequences on the health status at subsequent ages.

Treatment of ovariectomized rats with 17β-estradiol increases hepatic delta-6 desaturase enzyme expression and docosahexaenoic acid levels in hepatic and plasma phospholipids

Higher docosahexaenoic acid (DHA) in females compared with males suggests ovarian hormones increase DHA production. Eight-week old rats were ovariectomized or sham operated (SHAM), and ovariectomized rats were treated with implanted pellets providing 17β-estradiol (OVX+E), progesterone (OVX+P), both (OVX+PE) or neither (OVX) for 14 days. Immunoblot and fatty acid analysis were performed on all samples, and microarray analysis was performed on OVX and SHAM groups. Increased Δ6-desaturase in OVX relative to SHAM was observed by microarray (12% higher) and immunoblot (31% higher). OVX+E and OVX+PE rats had 39% and 42% higher Δ6-desaturase content, respectively, compared with OVX. OVX+E and OVX+PE also increased phospholipid DHA concentrations in liver (increase of 34% and 40%, respectively) and plasma (increase of 70% and 74%, respectively) relative to OVX. Progesterone exerted no effect on Δ6-desaturase or DHA. These results indicate that 17β-estradiol increases DHA through increased Δ6-desaturase, possibly explaining sex differences in DHA.

Targeted alteration of dietary n-3 and n-6 fatty acids for the treatment of chronic headaches: a randomized trial

Omega-3 and n-6 fatty acids are biosynthetic precursors to lipid mediators with antinociceptive and pronociceptive properties. We conducted a randomized, single-blinded, parallel-group clinical trial to assess clinical and biochemical effects of targeted alteration in dietary n-3 and n-6 fatty acids for treatment of chronic headaches. After a 4-week preintervention phase, ambulatory patients with chronic daily headache undergoing usual care were randomized to 1 of 2 intensive, food-based 12-week dietary interventions: a high n-3 plus low n-6 (H3-L6) intervention, or a low n-6 (L6) intervention. Clinical outcomes included the Headache Impact Test (HIT-6, primary clinical outcome), Headache Days per month, and Headache Hours per day. Biochemical outcomes included the erythrocyte n-6 in highly unsaturated fatty acids (HUFA) score (primary biochemical outcome) and bioactive n-3 and n-6 derivatives. Fifty-six of 67 patients completed the intervention. Both groups achieved targeted intakes of n-3 and n-6 fatty acids. In intention-to-treat analysis, the H3-L6 intervention produced significantly greater improvement in the HIT-6 score (-7.5 vs -2.1; P<0.001) and the number of Headache Days per month (-8.8 vs -4.0; P=0.02), compared to the L6 group. The H3-L6 intervention also produced significantly greater reductions in Headache Hours per day (-4.6 vs -1.2; P=0.01) and the n-6 in HUFA score (-21.0 vs -4.0%; P<0.001), and greater increases in antinociceptive n-3 pathway markers 18-hydroxy-eicosapentaenoic acid (+118.4 vs +61.1%; P<0.001) and 17-hydroxy-docosahexaenoic acid (+170.2 vs +27.2; P<0.001). A dietary intervention increasing n-3 and reducing n-6 fatty acids reduced headache pain, altered antinociceptive lipid mediators, and improved quality-of-life in this population.