Polyunsaturated Fatty Acids EPA Research Articles

Pro-Resolving Inflammatory Effects of a Marine Oil Enriched in Specialized Pro-Resolving Mediators (SPMs) Supplement and Its Implication in Patients with Post-COVID Syndrome (PCS).

This study aimed to evaluate the eicosanoid and pro-resolutive parameters in patients with Post-COVID Syndrome (PCS) during a 12-week supplementation with a marine oil enriched in specialized pro-resolving mediators (SPMs). This study was conducted on 53 adult patients with PCS. The subjects included must have had a positive COVID-19 test (PCR, fast antigen test, or serologic test) and persistent symptoms related to COVID-19 at least 12 weeks before their enrolment in the study. The following parameters were evaluated: polyunsaturated fatty acids EPA, DHA, ARA, and DPA; specialized pro-resolving mediators (SPMs), 17-HDHA, 18-HEPE, 14-HDHA, resolvins, maresins, protectins, and lipoxins. The eicosanoids group included prostaglandins, thromboxanes, and leukotrienes. The development of the clinical symptoms of fatigue and dyspnea were evaluated using the Fatigue Severity Scale (FSS) and the Modified Medical Research Council (mMRC) Dyspnea Scale. Three groups with different intake amounts were evaluated (daily use of 500 mg, 1500 mg, and 3000 mg) and compared to a control group not using the product. In the serum from patients with PCS, an increase in 17-HDHA, 18-HEPE, and 14-HDHA could be observed, and a decrease in the ratio between the pro-inflammatory and pro-resolutive lipid mediators was detected; both differences were significant (p < 0.05). There were no differences found between the three treatment groups. Fatigue and dyspnea showed a trend of improvement after supplementation in all groups. A clear enrichment in the serum of the three monohydroxylated SPMs could be observed at a dosage of 500 mg per day. Similarly, a clear improvement in fatigue and dyspnea was observed with this dosage.

Correlations between omega-3 fatty acids and inflammatory/glial abnormalities: the involvement of the membrane and neurotransmitter dysfunction in schizophrenia.

Macrophages or T-lymphocytes triggered inflammation and, consequently, activated glial cells may contribute to neuroinflammation and neurotransmitter dysfunction in schizophrenia (SZ), while omega(n)-3 polyunsaturated fatty acids (PUFAs) can attenuate some SZ symptoms through anti-inflammatory effects. However, the correlations between macrophage/T-lymphocyte-produced cytokines and glia phenotypes, between inflammatory status and PUFAs composition, between cytokines and neurotransmitter function, and between n-3 PUFAs and neurotransmitter abnormality in SZ are unclear. Changes in T-helper (h) patterns, peripheral macrophage/glial markers, PUFAs profile, membrane fluidity, and neurotransmitter functions were evaluated in SZ patients (n = 50) and healthy controls (n = 30) using ELISA, gas chromatography, fluorescence anisotropy techniques, and HPLC, respectively. Compared to the control, blood lymphocyte proliferation, the concentration of macrophage/microglia phenotype M1 markers, including cytokines IL-1β, TNF-α (Th1) and IL-6 (Th2), and astrocyte phenotype A1 marker S100β was significantly increased, while IL-17 and n-3 PUFAs contents, n-3/n-6 ratio, and membrane fluidity (FLU) were significantly decreased in SZ. Moreover, increased DA and HVA, decreased 5-HT and NE, and their metabolites appeared in SZ. Moreover, negative correlations between IL-6 and A2 marker Brain-Derived Neurotrophic Factor (BDNF) or n-3 PUFAs EPA and between IL-1β and FLU or 5HIAA, while positive correlations between EPA and 5-HIAA and between FLU and DHA were found in SZ. These findings showed (1) no clear Th pattern, but pro-inflammatory-dominant immunity occurred; (2) the pro-inflammatory pattern may result in the activated microglia M1 and astrocyte A1 phenotype; and (3) increased pro-inflammatory cytokines were related to decreased n-3 PUFA and decreased membrane fluidity and dysfunctional neurotransmitter systems in SZ.

Prospective dietary polyunsaturated fatty acid intake is associated with trajectories of fatty liver disease: an 8 year follow-up study from adolescence to young adulthood

Background and aimDietary fat intake has long been associated with fatty liver. Our study aimed to determine the effect of dietary fats on longitudinal fatty liver index (FLI) trajectories from adolescence to young adulthood.MethodsNine hundred eighty-five participants in the Raine Study, Perth, Western Australia, Australia, had cross-sectional assessments at ages 14, 17, 20 and 22 years, during which anthropometric measurements and blood tests were obtained. FLI trajectories were derived from the longitudinal FLI results. Dietary fat intake was measured with a semi-quantitative food frequency questionnaire at 14 years and log multinominal regression analyses were used to estimate relative risks.ResultsThree FLI trajectories were identified and labelled as stable-low (79.1%, N = 782), low-to-high (13.9%, N = 132), and stable-high (7%, N = 71). The low-to-high group associated with an increased intake of the long-chain polyunsaturated fatty acids EPA, DPA and DHA (RR 1.27, 95% CI 1.10–1.48) relative to the stable-low group. Compared to the stable-low group, omega-6 and the ratio of omega-6 to omega-3 in the stable-high group were associated with an increased relative risk of 1.34 (95% CI 1.02–1.76) and 1.10 (95% CI 1.03–1.16), respectively.ConclusionFor those at high risk of fatty liver in early adolescence, high omega-6 fatty acid intake and a high ratio of omega-6 to omega-3 fatty acids are associated with increased risk of fatty liver. There should be caution in assuming these associations are causal due to possible undetected and underestimated confounding factors.

The Polyunsaturated Fatty Acids EPA and DHA Prevent Myocardial Infarction-induced Heart Failure by Inhibiting p300-HAT Activity in Rats.

The Polyunsaturated Fatty Acids EPA and DHA Prevent Myocardial Infarction-induced Heart Failure by Inhibiting p300-HAT Activity in Rats.

Lumpfish (Cyclopterus lumpus) used as cleaner fish: Characterization and suitability for human consumption

Farmed lumpfish (Cyclopterus lumpus) is frequently used as cleaner fish in Norwegian salmon aquaculture. During the period in the net cage, the lumpfish feed on salmon lice. After a time, the fish stop eating the lice and are then withdrawn from the net cage without further exploitation. In this study, the nutritional value of lumpfish was characterized to assess its suitability as a human food. The lumpfish were collected from two separate salmon aquaculture facilities and analyzed for proximate composition, amino acids, fatty acids, vitamins, minerals, environmental pollutants, and heavy metals. The water and protein content were approximately 90 and 6%, respectively. The protein contained all essential amino acids. The fat content ranged from 0.9 to 3.7% with a high level of the long chain polyunsaturated fatty acids EPA (eicosapentaenoic acid; 20:5n-3) and DHA (docosahexaenoic acid; 22:6n-3). Lumpfish may be a good source of B12 and D3 vitamins, however, the content of several minerals was low. The environmental pollutants and heavy metals were below the EU maximum levels, making the lumpfish safe for human consumption. Overall, our results indicate a potential to exploit the lumpfish, even after its time as a cleaner fish.

Dietary supplementation with docosahexaenoic acid rich fish oil increases circulating levels of testosterone in overweight and obese men

Pre-clinical evidence suggests that omega-3 (n-3) polyunsaturated fatty acids (PUFAs), in particular, docosahexaenoic acid (DHA) have been shown to affect testosterone synthesis in males. This study is a secondary analysis of a randomized controlled trial which determined the effect of a DHA-enriched fish oil supplement on insulin resistance. The aim of the current study was to determine whether testosterone levels change in response to a DHA-enriched fish oil intervention. Overweight and obese men and women without diabetes were recruited to the study. Participants were stratified by sex and randomly allocated to intervention (860 mg DHA + 120 g EPA/day; FO) or an isocaloric control (corn oil; CO) for 12 weeks. A fasted blood sample was collected pre- and post-intervention. Fatty acid composition of erythrocyte membranes was measured using gas chromatography. Total testosterone and metabolic parameters were measured by an accredited commercial pathology laboratory. Sixty-one participants (CO/FO: n = 29/32) were included in the current analysis (male: n = 22, 36.07%). DHA-enriched fish oil supplementation increased total testosterone levels in males after adjusting for baseline levels, age and BMI. There was no treatment effect in females. Changes in testosterone levels in males were positively associated with changes to omega-3 PUFAs EPA and DHA and inversely correlated with omega-6 PUFA, arachidonic acid and dihomo-gamma-linolenic acid content in erythrocyte membranes, and was associated with beneficial changes to fasting insulin and HOMA-IR across the course of the study. DHA-enriched fish oil supplementation increases testosterone levels in overweight and obese men. Further research is warranted to substantiate these findings with a larger sample size and a longer follow-up period.

Cognitive improvements in a rat model with polyunsaturated fatty acids EPA and DHA through α7-nicotinic acetylcholine receptors

ABSTRACT The α7-nicotinic acetylcholine receptor (α7-nAChR) is a recognized target for the treatment of dementia associated with aging and certain developmental disorders. This study evaluates memory improvement in a rat model by the effects of polyunsaturated fatty acids EPA and DHA mediated by α7-nAChR, as well as identifying the minimum dose of EPA/DHA required to generate an effect in the improvement of cognition through α7-nAChR in rats. The modified Y-maze and object recognition behavioral tests were performed in scopolamine-induced amnesic rats, in order to study the effects of long-term supplementation (10, 15, 30, and 60 mg/kg) of the two polyunsaturated fatty acids in improving cognitive impairment. Cognitive enhancement by EPA and DHA is mediated through α7-nAChRs, as evidenced by memory recovery after treatment with a selective α7-nAChR antagonist, methyllycaconitine (MLA). Tacrine, a centrally active acetylcholinesterase inhibitor, and PNU282987, an α7-nAChR agonist, are employed as reference standards. Our data demonstrate that 15 mg/kg EPA and DHA can affect cholinergic neurotransmission positively through memory and cognition and, thus, can exert a beneficial action on learning and memory deficits.

Differentiation of 3T3‐L1 adipocytes with arachidonic acid increases inflammatory markers

Adipose tissue is responsible for insulating internal organs, storing energy for times of negative energy balance, and secreting adipokines into circulation. The major cell types found in adipose tissue include undifferentiated adipocytes (pre‐adipocytes), adipocytes, and adipose tissue macrophages macrophages (ATMs). Adipocytes and ATMs are the major sources of adipokines, adipose tissue cytokines with functions ranging from inflammatory mediators to metabolic regulators. Polyunsaturated fatty acids (PUFAs) have been shown to affect the differentiation and lipid droplet formation in 3T3‐L1 adipocytes, but few studies have examined their effects on inflammatory adipokine production from these cells. Adipocyte differentiation, which is marked by lipid droplet (triacylglycerol; TAG) accumulation, is regulated by various transcription activators, including a splice variant of the nuclear receptor PPAR□. PUFAs are major regulators of PPAR□. For example, the n‐3 PUFA EPA has been shown to have an effect on lipid droplet size through effects on lipid catabolism, as well as mediate reductions in pro‐inflammatory adipokine secretion in favor of anti‐inflammatory secretions. The objectives of this experiment were to determine the effects of n‐3 and ‐6 PUFAs on TAG lipolysis, as measured by free fatty acid (FFA) release, and inflammatory cytokine production, as measured by interleukin (IL)‐6 and macrophage inflammatory protein (MIP)‐1α production. In order to examine these effects, the 3T3‐L1 cells were differentiated in media with 100μM of PUFA treatment (α‐linoleic acid [LA], arachidonic acid [ARA], and EPA), followed by a 6 h, 1μg/mL of lipopolysaccharide (LPS) challenge. Fully differentiated 3T3‐L1 adipocytes under these treatments did not release FFA in quantifiable amounts. The LPS+ARA treatment resulted in significantly higher levels of MIP‐1□ (26.3±2.5 pg/ml) and IL‐6 (146.13±17.0 pg/ml) in conditioned media, compared to control (MIP‐1□:0.55±2.5; IL‐6:0.23±17.0), LPS (MIP‐1□:0.06±2.5; IL‐6:16.5±17.0), and LPS+LA (MIP‐1□:7.5±2.5; IL‐6:27.0±17.0). Cells treated with LPS+EPA released similar amounts of MIP‐1□ (14.9±2.5) but significantly lower amounts of IL‐6 (20.3±17.0) compared to LPS+ARA‐treated cells. These data suggest that differentiating 3T3‐L1 adipocytes in the presence of the n‐6 PUFA ARA results in increased release of LPS‐stimulated IL‐6 and MIP‐1□. These results indicate a role of this n‐6 fatty acid on adipocyte‐derived inflammation.Support or Funding InformationLaurie Bukovac Hodgson &amp; David Hodgson Endowed Fund, as well as the Denison Summer Science Research Supply Fund

DPA shows comparable chemotherapy sensitizing effects as EPA upon cellular incorporation in tumor cells.

Dietary supplementation with ω-3 polyunsaturated fatty acids (PUFAs) has been reported to enhance the sensitivity of tumor cells towards chemotherapy. Most enhancing effects are described for ω-3 PUFAs EPA and DHA; less evidence is available with the intermediate DPA. We studied the chemotherapy enhancing effects of EPA, DPA and DHA in murine colon C26 adenocarcinoma cells and showed that DPA displayed similar chemosensitizing effects as EPA. Moreover, EPA supplementation increased cellular DPA content. In a C26 tumor-bearing mouse model, we studied the incorporation of ω-3 PUFA in tumor and skeletal muscle after a diet with different ω-3 PUFA sources. Although little DPA was present in the fatty acid food sources, in those that contained considerable EPA concentrations, DPA levels were higher in tumor and muscle tissue. From these studies, we conclude that EPA and DPA show chemosensitizing effects and that intake of EPA or EPA-containing nutrition leads to increased cellular DPA content by elongation. These findings support the use of ω-3 PUFA containing nutritional supplementations in cancer patients during chemotherapy treatment.

Delta-6-desaturase (FADS2) inhibition and omega-3 fatty acids in skeletal muscle protein turnover

Polyunsaturated fatty acids (PUFAs) are essential dietary components. They are not only used for energy, but also act as signaling molecules. The delta-6 desaturase (D6D) enzyme, encoded by the FADS2 gene, is one of two rate limiting enzymes that convert the PUFA precursors – α-linolenic (n-3) and linoleic acid (n-6) to their respective metabolites. Alterations in the D6D enzyme activity alters fatty acid profiles and are associated with metabolic and inflammatory diseases including cardiovascular disease and type 2 diabetes. Omega-3 PUFAs, specifically its constituent fatty acids DHA and EPA, are known for their anti-inflammatory ability and are also beneficial in the prevention of skeletal muscle wasting, however the mechanism for muscle preservation is not well understood. Moreover, little is known of the effects of altering the n-6/n-3 ratio in the context of a high-fat diet, which is known to downregulate protein synthesis. Twenty C57BL6 male mice were fed a high-fat lard (HFL, 45% fat (mostly lard), 35% carbohydrate and 20% protein, n-6:n-3 PUFA, 13:1) diet for 6 weeks. Mice were then divided into 4 groups (n = 5 per group): HFL– , high-fat oil– (HFO, 45% fat (mostly Menhaden oil), 35% carbohydrate and 20% protein, n-6:n-3 PUFA, 1:3), HFL+ (HFL diet plus an orally administered FADS2 inhibitor, 100 mg/kg/day), and HFO+ (HFO diet plus an orally administered FADS2 inhibitor, 100 mg/kg/day). After 2 weeks on their respective diets and treatments, animals were sacrificed and gastrocnemius muscle harvested. Protein turnover signaling were analyzed via Western Blot. 4-EBP1 and ribosomal protein S6 expression were measured. A two-way ANOVA revealed no significant change in the phosphorylation of both 4EBP-1 and ribosomal protein S6 with diet or inhibitor. There was a significant reduction in STAT3 phosphorylation with the inhibition of FADS2 (p = 0.03). Additionally, we measured markers of protein degradation through levels of FOXO phosphorylation, ubiquitin, and LC3B expression; there was a trend towards increased phosphorylation of FOXO (p = 0.08) and ubiquitinated proteins (p = 0.05) with FADS2 inhibition. LC3B expression, a marker of autophagy, was significantly higher in the HFL plus FADS2 inhibition group from all other comparisons. Lastly, we analyzed activation of mitochondrial biogenesis which is closely linked with protein synthesis through PGC1-α and Cytochrome-C expression, however no significant differences were associated with either marker across all groups. Collectively, these data suggest that the protective effects of muscle mass by omega-3 fatty acids are from inhibition of protein degradation. Our aim was to determine the role of PUFA metabolites, DHA and EPA, in skeletal muscle protein turnover and assess the effects of n-3s independently. We observed that by inhibiting the FADS2 enzyme, the protective effect of n-3s on protein synthesis and proliferation was lost; concomitantly, protein degradation was increased with FADS2 inhibition regardless of diet.

EPA:DHA 6:1 is a superior omega-3 PUFAs formulation attenuating platelets-induced contractile responses in porcine coronary and human internal mammary artery by targeting the serotonin pathway via an increased endothelial formation of nitric oxide

At arterial sites of endothelial denudation and dysfunction, activated platelets contribute to vascular injury through the release of potent contracting factors such as serotonin (5-HT). This study evaluated whether omega-3 polyunsaturated fatty acids (PUFAs), known to protect the vascular system, are able to prevent platelets-induced contractile responses in isolated arteries and, if so, to investigate the underlying mechanism and the importance of the omega-3 PUFAs formulation.Porcine coronary arteries (PCA), human internal mammary arteries (IMA) and washed human platelets were prepared and vascular reactivity was studied in organ chambers.In PCA rings, aggregating platelets caused concentration-dependent contractions that were significantly inhibited by the 5-HT2A receptor antagonist ketanserin, and by EPA:DHA 6:1 but not EPA:DHA 1:1 at 0.4% v/v. EPA:DHA 6:1 also prevented the 5-HT-induced contractions but affected only slightly those to the thromboxane A2 analogue U46619. The inhibitory effect of EPA:DHA 6:1 on platelets-induced contractions was not observed in rings without endothelium, and prevented by an eNOS inhibitor but not by inhibitors of endothelium-dependent hyperpolarization. In IMA rings, EPA:DHA 6:1 but not EPA:DHA 1:1 at 0.4% v/v significantly prevented the 5-HT-induced contraction, and induced greater endothelium-dependent relaxations than bradykinin and acetylcholine sensitive to an eNOS inhibitor.EPA:DHA 6:1 strongly inhibits platelets- and 5-HT-induced contractions in PCA rings and those to 5-HT in IMA rings most likely through an increased endothelial formation of NO. These findings suggest that the omega-3 PUFAs EPA:DHA 6:1 formulation may be of interest to prevent platelets-induced vascular injury at arterial sites of endothelial dysfunction.

Diets Rich in Stearidonic Acid Impact on Joint Inflammation in a Murine Model of Rheumatoid Arthritis

INTRODUCTIONChronic inflammation is the hallmark of inflammatory diseases, including rheumatoid arthritis (RA). While the etiology of RA remains unclear, several cell types promote the inflammatory stage of the disease by producing inflammatory lipid mediators and cytokines. Omega‐3 polyunsaturated fatty acids (PUFA) from fish oil are precursors of immunoregulatory lipids and their consumption has been shown to moderate inflammation in RA patients. However, the sustainability of fish oils has been questioned due to depleting ocean resources. Plant‐derived oils rich in stearidonic acid (SDA, 18:4 n‐3) such as Buglossoides arvensis oil may be alternative, sustainable and effective sources of dietary omega‐3 PUFA.OBJECTIVEThe aim of this study is to evaluate the effects of dietary Buglossoides arvensis oil on disease severity in a mouse model of induced RA.METHODSWe compared the effects of a control diet (based on the typical western human diet) with diets enriched with a low dose (3% of kcal) or a high dose of Buglossoides oil (10% kcal) on the (K/BxN) murine model of RA. C57B6 mice (n = 25–31 per group) consumed experimental diets for 3 weeks. RA was then induced by the intraperitoneal injection of 150 μl of serum from K/BxN mice and disease progression was followed for 9 days. Liver fatty acid profiles were measured on day 9 to determine the impact of diet on tissue lipids. Disease‐associated inflammation was measured daily over 9 days by clinical index score and ankle thickness, and by inflammatory cell infiltration into joints measured histologically following H&amp;E staining at day 9. Since energy metabolism is impacted in RA and by omega‐3 PUFA consumption, mitochondrial oxidative capacity was also measured in soleus muscles on day 9. All studies were approved by the institutional review board protocol (Université de Moncton). Guidelines of the Canadian Council on Animal Care were followed in a protocol approved by the Animal Welfare Committee at Université de Moncton.RESULTSLiver fatty acid profiles were significantly different between all groups. Specifically, omega‐3 PUFA content, including SDA, EPA and DPA significantly increased (2‐way ANOVA, p &lt; 0.05) with the dose of dietary Buglossoides oil. DHA was significantly increased in both Buglossoides groups compared to control mice. Mice consuming high dose Buglossoides diets showed significantly elevated inflammation scores (2‐way repeated measures ANOVA, p &lt; 0.05) compared to control diets, whereas low dose Buglossoides diets showed significantly decreased inflammation scores (p &lt; 0.05) compared to the control group. Mitochondrial oxidative capacity was significantly decreased in animals consuming the high dose Buglossoides diet compared to the other two groups (1‐way ANOVA, p &lt; 0.05).CONCLUSIONThese findings suggest that consumption of diets containing moderate quantities of SDA‐rich oil (a human equivalent dose of 6.6 g of oil (1.3 g SDA) per day based on percent calories) can alleviate inflammation associated with RA. Conversely, consumption of a daily human equivalent dose of 22 g of SDA‐rich oil exacerbates inflammation in this murine model of RA. Lipidomic and cytokine analysis of inflamed paws may provide mechanistic explanations of these dietary effects.Support or Funding InformationStudy was funded by Nature's Crops International, New Brunswick Innovation Foundation, Atlantic Canada Opportunities Agency, Canadian Institutes of Health Research, New Brunswick Health Research Foundation and Natural Sciences and Engineering Research Council of Canada.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Nutrigenomic studies on hilsa to evaluate flesh quality attributes and genes associated with fatty acid metabolism from the rivers Hooghly and Padma

The Indian shad hilsa (Tenualosa ilisha), a commercially important food fish rich in oils, enjoys high consumer preference in the South Asian countries owing to its unique flavour and culinary properties. The present study was undertaken with the primary objective of determining the flesh quality attributes of hilsa in terms of nutritive value (gross chemical composition, amino acid, fatty acid and mineral composition), pH, water holding capacity (WHC) and expression of genes associated with fatty acid metabolism and flesh quality. Additionally, comparative studies on the flesh quality attributes in hilsa from two distributaries of river Ganga i.e. Hooghly and Padma were also carried out. A high WHC (>80%) suggested juicy and tender nature of hilsa meat. The protein content was 18–21% in hilsa from both the rivers and essential amino acid lysine, valine and functional amino acids leucine and arginine were significantly higher in Hooghly hilsa (P<0.05). The predominance of umami taste amino acids, glutamic acid and aspartic acid and sweet taste amino acids, serine, glycine and alanine in hilsa from both the rivers could be the contributing factors to its unique flavour. The fat content in hilsa from river Hooghly and Padma were found to be 9.94 and 7.84%, respectively. The concentration of flavouring fatty acids like saturated fatty acids (SFA) (myristic acid) and omega (ω)-3 polyunsaturated fatty acids (PUFAs) (linoleic acid, α-linolenic acid, arachidonic acid, eicosapentaenoic acid, EPA and docosahexaenoic acid, DHA) were significantly higher in Hooghly hilsa (P<0.05). Among the genes associated with fatty acid metabolism studied, expression of cluster of differentiation (CD36), acetyl CoA oxidase (ACO), fatty acid synthase (FAS), peroxisome proliferator activated receptor beta (PPARβ), peroxisome proliferator activated receptor gamma (PPARγ) and desaturase were significantly higher in Padma hilsa (P<0.05), and the change was <2 fold. Comparative gene expression profiling of flesh quality genes (actin, GAPDH, LDH, TPI) showed similar levels of expression in hilsa from both the rivers (P<0.05). The nutrigenomic information generated on various flesh quality attributes of hilsa has enriched the knowledgebase. Further, from comparative nutrient analysis on hilsa from river Hooghly and Padma, it was observed that Hooghly hilsa is superior in terms of oil content, ω-3 PUFAs EPA and DHA and essential amino acids; however, the expression profile of genes associated with flesh quality were found to be similar. Thus, within the scope of the present study, Hooghly hilsa (medium size category, 500–700g size) was found to be nutritionally superior.

Effect of harvesting processes on the lipid yield and fatty acid profile of the marine microalga Nannochloropsis oculata

The effect of different methods of biomass concentration and salt removal on the lipid yield and fatty acid profile of the marine microalga Nannochloropsis oculata was evaluated. The microalgae were subjected to nine treatments: (1) centrifugation, (2) centrifugation+washing with H2O, (3) centrifugation+washing with ammonium formate, (4) flocculation with NaOH, (5) flocculation with NaOH+washing with H2O, (6) flocculation with NaOH+washing with ammonium formate, (7) flocculation with NaOH and neutralization with HCl, (8) flocculation with NaOH, neutralization with HCl+washing with H2O, and (9) flocculation with NaOH, neutralization with HCl+washing with ammonium formate. Flocculation with the addition of NaOH was effective at concentrating biomass (>90%) but interfered with lipid extraction because it exhibited a lower lipid yield (4.40±0.1%) compared with centrifugation (45.4±0.8%). Moreover, important polyunsaturated fatty acids, such as eicosapentaenoic acid (EPA C20:5) and eicosatetraenoic acid (ETA C20:4), disappeared when NaOH was used. Centrifugation plus washing the biomass with ammonium formate was more effective than other treatments, leading to higher lipid yields, as well as larger amounts of the polyunsaturated fatty acids EPA and ETA. However, it is a very expensive harvesting method. Thus, the main finding of the present study is that microalgae concentration processes can affect lipid and fatty acid extraction in massive microalgae production; therefore, it is necessary to carefully choose the harvest process to be used in large-scale microalgae production.

Omega-3 and omega-6 fatty acid intakes and endometrial cancer risk in a population-based case–control study

Animal and laboratory studies suggest that long-chain omega-3 (n-3) fatty acids, a type of polyunsaturated fat found in fatty fish, may protect against carcinogenesis, but human studies on dietary intake of polyunsaturated fats and fish with endometrial cancer risk show mixed results. We evaluated the associations between endometrial cancer risk and intake of fatty acids and fish in a population-based sample of 556 incident cancer cases and 533 age-matched controls using multivariate unconditional logistic regression methods. Although total n-3 fatty acid intake was not associated with endometrial cancer risk, higher intakes of eicosapentaenoic (EPA 20:5) and docosahexaenoic (DHA 22:6) fatty acids were significantly associated with lower risks (OR = 0.57, 95 % CI: 0.39-0.84; OR = 0.64, 95 % CI: 0.44-0.94; respectively) comparing extreme quartiles. The ratio of n-3:n-6 fatty acids was inversely associated with risk only on a continuous scale (OR = 0.84, 95 % CI: 0.71-0.99), while total fish intake was not associated with risk. Fish oil supplement use was significantly associated with reduced risk of endometrial cancer: OR = 0.63 (95 % CI: 0.45-0.88). Our results suggest that dietary intake of the long-chain polyunsaturated fatty acids EPA and DHA in foods and supplements may have protective associations against the development of endometrial cancer.

Activation of n-3 polyunsaturated fatty acids as oxime esters: a novel approach for their exclusive incorporation into the primary alcoholic positions of the glycerol moiety by lipase

A novel approach has been developed for activating the highly bioactive long-chain n-3 polyunsaturated fatty acids EPA and DHA as oxime esters and incorporating them exclusively to the end-positions of glycerol and enantiopure 1-O-alkylglycerols. The Candida antarctica lipase B was observed to display a superb regioselectivity when using the acetoxime esters of EPA and DHA as acyldonors under mild condition to keep acyl-migration side-reaction under complete control. Regiopure 1,3-diacylglycerols, 1-O-alkyl-3-acyl-sn-glycerols and their antipodes possessing EPA and DHA were afforded in very high purity and yields.

Associations between omega-3 poly-unsaturated fatty acids from fish consumption and severity of depressive symptoms: An analysis of the 2005–2008 National Health and Nutrition Examination Survey

Fish is the primary source of dietary omega-3 poly-unsaturated fatty acids EPA and DHA, which have been reported to reduce depressive symptoms in clinical trials. We assessed the association between fish consumption and depressive symptoms in a nationally representative sample of 10,480 adults from the 2005–2008 National Health and Nutrition Examination Survey. Depressive symptoms were classified by severity using the Patient Health Questionnaire. Fish meal consumption reported in 30-day food frequency questionnaires, and EPA+DHA intake computed from 24-h dietary recalls were evaluated in relation to depressive symptoms using multivariable ordinal logistic regression. Consumption of breaded fish showed an increased risk of greater depressive symptom severity, while all fish, non-breaded fish, and shell fish were not associated. Any EPA+DHA intake was significantly associated with fewer depressive symptoms. Exposure-response analyses revealed no clear patterns for any intake measures. Inconsistent patterns of associations in our study may be partially explained by exposure misclassification.

Validation of a Food Frequency Questionnaire to Assess Intake of n-3 Polyunsaturated Fatty Acids in Subjects with and without Major Depressive Disorder

The role of n-3 polyunsaturated fatty acids (PUFAs) in psychiatric illness is a topic of public health importance. This report describes development and biomarker validation of a 21-item, self-report food frequency questionnaire (FFQ) intended for use in psychiatric research to assess intake of α-linolenic acid (18:3n-3 [ALA]), docosahexaenoic acid (22:6n-3 [DHA]), and eicosapentaenoic acid (20:5n-3 [EPA]). In a cross-sectional study conducted from September 2006 to September 2008, sixty-one ethnically diverse adult participants with (n=34) and without (n=27) major depressive disorder completed this n-3 PUFA FFQ and provided a plasma sample. Plasma levels of n-3 PUFAs EPA and DHA, and n-6 PUFA arachidonic acid (20:4n-6 [AA]) were quantified by gas chromatography. Using Spearman's ρ, FFQ-estimated intake correlated with plasma levels of DHA ( r=0.50; P<0.0001) and EPA ( r=0.38; P=0.002), but not with ALA levels ( r=0.22; P=0.086). Participants were classified into quartiles by FFQ-estimated intake and plasma PUFA concentrations. Efficacy of the FFQ to rank individuals into same or adjacent plasma quartiles was 83% for DHA, 78.1% for EPA, and 70.6% for ALA; misclassification into extreme quartiles was 4.9% for DHA, 6.5% for EPA, and 8.2% for ALA. FFQ-estimated EPA intake and plasma EPA were superior to plasma AA levels as predictors of the plasma AA to EPA ratio. This brief FFQ can provide researchers and clinicians with valuable information concerning dietary intake of DHA and EPA.

Effect of Dietary Fatty Acids on Inflammatory Gene Expression in Healthy Humans

Over the past 100 years, changes in the food supply in Western nations have resulted in alterations in dietary fatty acid consumption, leading to a dramatic increase in the ratio of omega-6 (omega6) to omega3 polyunsaturated fatty acids (PUFA) in circulation and in tissues. Increased omega6/omega3 ratios are hypothesized to increase inflammatory mediator production, leading to higher incidence of inflammatory diseases, and may impact inflammatory gene expression. To determine the effect of reducing the omega6/omega3 ratio on expression of inflammatory pathway genes in mononuclear cells, healthy humans were placed on a controlled diet for 1 week, then given fish oil and borage oil for an additional 4 weeks. Serum and neutrophil fatty acid composition and ex vivo leukotriene B(4) production from stimulated neutrophils were measured at the start and end of the supplementation period and after a 2-week washout. RNA was isolated from mononuclear cells and expression of PI3K, Akt, NFkappaB, and inflammatory cytokines was measured by real-time PCR. A marked increase was seen in serum and neutrophil levels of long-chain omega3 PUFA concomitant with a reduction in the omega6/omega3 PUFA ratio (40%). The ex vivo capacity of stimulated neutrophils to produce leukotriene B(4) was decreased by 31%. Expression of PI3Kalpha and PI3Kgamma and the quantity of PI3Kalpha protein in mononuclear cells was reduced after supplementation, as was the expression of several proinflammatory cytokines. These data reveal that PUFA may exert their clinical effects via their capacity to regulate the expression of signal transduction genes and genes for proinflammatory cytokines.

Fatty acid composition of larvae of the sand dollar Dendraster excentricus (Echinodermata) might reflect FA composition of the diets

Fatty acid (FA) requirements of echinoderm larvae were examined by a study of the FA composition, growth, and development of Dendraster excentricus larvae fed a microencapsulated diet, and two algal diets. Larvae were assigned to three treatments with three replicates per treatment, a microencapsulated diet, a single algal diet of Dunaliella tertiolecta and a mixed algal diet of Isochrysis galbana and Dunaliella tertiolecta. The percentage of saturated fatty acids (SAFA), short and long chain polyunsaturated fatty acids (PUFA) differed significantly among the algal diets and the microencapsulated diet. Differences in dietary FA composition influenced larval tissue FA composition. Eight day-old sand dollar larvae fed the single and mixed algal diets had a significantly higher percentage of the SAFA myristic acid (14:0), while eight day-old larvae fed the microencapsulated diet had a significantly higher percentage of the SAFA palmitic acid (16:0). Sixteen day-old competent larvae fed all three diets did not differ significantly in the percentage of myristic or palmitic acid. The algal diets had a higher percentage of the short chain PUFAs linolenic (LNA, 18:3n-3) and stearidonic acid (SDA, 18:4n-3) while the microencapsulated diet had the highest percentage of the long chain PUFAs eicosapentanoic acid (EPA, 20:5n-3) docosahexanoic acid (DHA, 22:6n-3) and arachidonic acid (AA, 20:4n-6). The percentage of short chain PUFAs, though high in the algal diets, was low in the larval tissues, while the percentage of long chain PUFAs, though low in the algal diets, was high in the larval tissues. Competent larvae fed the two algal diets had up to ten times the percentage of EPA and AA than those fed the microencapsulated diet. Unexpectedly, despite a high percentage of DHA and EPA in the microencapsulated diet, the percentage of these long chain PUFAs in the tissues of larvae fed this diet was extremely low. Eight day-old larvae fed the three diets did not differ significantly in total larval length. Competent larvae fed algal diets had significantly longer larval arms, bigger stomachs and larger rudiments than those fed the microencapsulated diet. This study indicates that early larval growth and development of Dendraster excentricus were not discernibly affected by differences in dietary FA composition of microencapsulated and algal diets but the competent larval stages were. Similar growth and development of competent echinoderm larvae fed microencapsulated or algal diets might be obtained by enriching the microencapsulated diets with the short chain PUFAs LNA and SDA, and the long chain PUFAs EPA and AA. This is an important research tool as microencapsulated feeds can be used to establish nutritional requirements of fatty acids for echinoderm larval development.