Docosahexaenoic Acid Ethyl Ester Research Articles

A novel self-micro-emulsifying delivery system (SMEDS) formulation significantly improves the fasting absorption of EPA and DHA from a single dose of an omega-3 ethyl ester concentrate

BackgroundAbsorption of EPA and DHA from Omega-3-acid ethyl ester (EE) concentrate supplements occurs most efficiently when taken in context of a fatty meal; adequate fat intake is required to release bile salts that emulsify and pancreatic enzymes that digest omega-3-containing lipids in the intestine. Current guidelines recommend reduction in fat intake and therefore there is a need to optimize the absorption of Omega-3 in those consuming low-fat or no-fat meals. To this end, BASF has developed an Absorption Acceleration Technology, a novel self-micro-emulsifying delivery system (SMEDS) formulation of highly concentrated Omega-3-acid EE which enables rapid emulsification and microdroplet formation upon entering the aqueous environment of the gut therefore enhances the absorption.MethodsTwo separate single dose, crossover studies were conducted to determine the relative bioavailability of omega-3-acid EE concentrate, either as a novel SMEDS formulation (PRF-021) or as control, in healthy fasted male and female adults at two dose levels (Study 1 “low dose”: 630 mg EPA + DHA in PRF-021 vs. 840 mg EPA + DHA in control; Study 2 “high dose”: 1680 mg EPA + DHA in PRF-021 vs. 3360 mg EPA + DHA in control). Blood samples were collected immediately before supplementation and at defined time intervals for 48 h. Plasma concentration of total EPA and DHA were determined for pharmacokinetic analysis, area under the curve (AUC) and maximum observed concentration (Cmax) was determined.ResultsTotal EPA plus DHA absorption from SMEDS formulation PRF-021 were 6.4 and 11.5 times higher compared to control in low- and high-dose studies respectively, determined as the ratio of baseline corrected, dose normalized AUC0-24h of PRF-021 over that of control. EPA and DHA individually showed differing levels of enhancement: the AUC0-24h ratio for EPA was 23.8 and 25.7 in low and high dose studies, respectively, and the AUC0-24h ratio for DHA was 3.6 and 5.6 in low and high dose studies, respectively. Cmax was also increased for both EPA and DHA 2.7- to 9.2-fold.ConclusionPRF-021 is a novel SMEDS formulation of Omega-3-acid EE demonstrating a marked improvement in absorption of a single dose of EPA and DHA EE under fasted conditions. This allows adequate absorption of Omega-3 from the supplement without the requirement of a high-fat meal.

Abstract 2224: Increased 15-lipoxygenase-1 activity limits tumor development in the azoxymethane mouse model of colon cancer: impact of omega-3-acid ethyl esters

Abstract Pro-inflammatory signaling has been shown to promote colorectal tumorigenesis and is a target for the development of effective chemopreventive approaches. The specialized pro-resolving lipid mediators (SPMs, e.g. resolvins), bioactive metabolites of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), actively terminate inflammation and have been proposed to possibly contribute to the anti-tumorigenic effects of DHA and EPA. The enzyme 15-lipoxygenase-1 (ALOX15) is a key biosynthetic enzyme in generation of resolvins. However, 15-LOX-1 expression is commonly lost during human CRC tumorigenesis starting in premalignant stages via transcriptional mechanisms independent of substrate availability. The impact of ALOX15 on DHA and EPA’s effects on tumorigenesis remain unknown. Mice with intestinal epithelium-specific expression of human ALOX15 (15-LOX-1-gut mice) and wild-type FVB controls were injected with azoxymethane (AOM, 7.5mg/kg) once weekly for 6w and followed for 20w. Mice were fed diet with 1% omega-3-acid ethyl esters (O3AEE, a pharmaceutical grade fish oil preparation of EPA and DHA ethyl esters) or control diet starting 3w before initiation with AOM. Colonic tumors developed in 10 of the 13 (77%) wild type (WT) mice fed control diet, 5 of the 10 (50%) WT mice fed O3AEE diet, 5 of the 12 (42%) 15-LOX-1-gut mice fed control diet, and 3 of the 10 (30%) 15-LOX-1-gut mice fed control diet. Lipid mediator levels were measured by liquid chromatography/ tandem mass spectrometry (LC-MS/MS). The SPMs resolvin E1 and D2 (RvE1, RvD2) as well as the pathway intermediates 18-HEPE and 17-HDHE were increased in ALOX15-gut mice on O3AEE (see Table; data are shown as ng/mg protein; mean ± SEM). Our results demonstrate that ALOX15 activity is important to DHA and EPA formation of resolvins and inhibition of colonic tumorigenesis. Supported by grants CPRIT RP150195 and NIH RO1 R01CA195686 SPMs in O3AEE or control diet fed miceWTWT15-LOX-1-gut15-LOX-1-gutControl dietO3AEE dietControl dietO3AEE diet18-HEPE00.46 + 0.500.82 + 0.3117-HDHE0.21 + 0.090.2 + 0.74.2 + 0.4113.35 + 3.1RvE10001.98 + 0.77RvD200.024 + 0.0240.17 + 0.0220.3 + 0.077 Citation Format: Xiangsheng Zuo, Jennifer K. Colby, Fuyao Liu, Shen Gao, Ling Wu, Jonathan C. Jaoude, Micheline J. Moussalli, Lin Tan, Peiying Yang, Imad Shureiqi. Increased 15-lipoxygenase-1 activity limits tumor development in the azoxymethane mouse model of colon cancer: impact of omega-3-acid ethyl esters [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2224. doi:10.1158/1538-7445.AM2017-2224

Enzymatic transesterification in a solvent-free system: synthesis of sn-2 docosahexaenoyl monoacylglycerol

The enzymatic transesterification of docosahexaenoic acid (DHA) ethyl ester with glycerol was carried out by using several immobilized lipases in a solvent-free system. This reaction involves the initial formation of sn-2 docosahexaenyl monoacylglycerol. This DHA derivative is highly relevant for improving the bioavailability of DHA and it has received increasing interest in the field of nutrition. Three commercial lipases, from Rhizomucor miehei (RML), Alcaligenes sp. (AQ) and Candida antarctica-fraction B (CALB) were immobilized by interfacial adsorption on a commercial hydrophobic support (a methacrylate resin containing octadecyl groups, Sepabeads C-18) and tested for glycerolysis of DHA ethyl ester. In certain cases (e.g. immobilized CALB), the transesterification reaction continues to the formation of triacylglycerol (80%) by using a very high excess of DHA ethyl ester ((115 mmols versus 1.24 mmols of glycerol and high temperatures (50 °C). However, the same biocatalyst working at lower temperatures, 37 °C, synthetizes a 90% of sn-2 monoacylglycerol even in the presence of that a high excess of DHA ethyl ester. Interestingly, immobilized RML derivative synthesizes a 98% of sn-2 monoacylglyceride (2-MG) in 15 min at 37 °C with a 4% of immobilized biocatalyst. These high activity and regioselectivity under very mild reaction conditions are very interesting for the thermal oxidative stability of the omega-3 fatty acid as well as for the thermal stability of the biocatalyst. Using Normal Phase HPLC-ELSD and accurate commercial markers, the formation of the 2-MG was confirmed.

The hydroxylated form of docosahexaenoic acid (DHA-H) modifies the brain lipid composition in a model of Alzheimer's disease, improving behavioral motor function and survival

We have compared the effect of the commonly used ω-3 fatty acid, docosahexaenoic acid ethyl ester (DHA-EE), and of its 2-hydroxylated DHA form (DHA-H), on brain lipid composition, behavior and lifespan in a new human transgenic Drosophila melanogaster model of Alzheimer's disease (AD). The transgenic flies expressed human Aβ42 and tau, and the overexpression of these human transgenes in the CNS of these flies produced progressive defects in motor function (antigeotaxic behavior) while reducing the animal's lifespan. Here, we demonstrate that both DHA-EE and DHA-H increase the longer chain fatty acids (≥18C) species in the heads of the flies, although only DHA-H produced an unknown chromatographic peak that corresponded to a non-hydroxylated lipid. In addition, only treatment with DHA-H prevented the abnormal climbing behavior and enhanced the lifespan of these transgenic flies. These benefits of DHA-H were confirmed in the well characterized transgenic PS1/APP mouse model of familial AD (5xFAD mice), mice that develop defects in spatial learning and in memory, as well as behavioral deficits. Hence, it appears that the modulation of brain lipid composition by DHA-H could have remedial effects on AD associated neurodegeneration. This article is part of a Special Issue entitled: Membrane Lipid Therapy: Drugs Targeting Biomembranes edited by Pablo V. Escribá.

Bioequivalence Demonstration for Ω-3 Acid Ethyl Ester Formulations: Rationale for Modification of Current Guidance

The US Food and Drug Administration (FDA) draft guidance for establishing bioequivalence (BE) of ω-3 acid ethyl esters (containing both eicosapentaenoic acid [EPA] and docosahexaenoic acid [DHA] as ethyl esters), used to treat severe hypertriglyceridemia, recommends the conduct of 2 studies: one with participants in the fasting state and one with participants in the fed state. For the fasting study, the primary measures of BE are baseline-adjusted EPA and DHA levels in total plasma lipids. For the fed study, the primary measures of BE are EPA and DHA ethyl esters in plasma. This guidance differs from that established for icosapent ethyl (EPA ethyl esters) in which the primary measure of BE is baseline-adjusted total EPA in plasma lipids for both the fasting and fed states. The FDA guidance for ω-3 acid ethyl esters is not supported by their physiologic characteristics and triglyceride-lowering mechanisms because EPA and DHA ethyl esters are best characterized as pro-drugs. This article presents an argument for amending the FDA draft guidance for ω-3 acid ethyl esters to use baseline-adjusted EPA and DHA in total plasma lipids as the primary measures of BE for both fasting and fed conditions. This change would harmonize the approaches for demonstration of BE for ω-3 acid ethyl esters and icosapent ethyl (EPA ethyl esters) products for future development programs and is the most physiologically rational approach to BE testing.

Effect of dietary n-3 fatty acids supplementation on fatty acid metabolism in atorvastatin-administered SHR.Cg-Leprcp/NDmcr rats, a metabolic syndrome model

The effects of cholesterol-lowering statins, which substantially benefit future cardiovascular events, on fatty acid metabolism have remained largely obscured. In this study, we investigated the effects of atorvastatin on fatty acid metabolism together with the effects of TAK-085 containing highly purified eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) ethyl ester on atorvastatin-induced n-3 polyunsaturated fatty acid lowering in SHR.Cg-Leprcp/NDmcr (SHRcp) rats, as a metabolic syndrome model. Supplementation with 10mg/kg body weight/day of atorvastatin for 17 weeks significantly decreased plasma total cholesterol and very low density lipoprotein cholesterol.Atorvastatin alone caused a subtle change in fatty acid composition particularly of EPA and DHA in the plasma, liver or erythrocyte membranes. However, the TAK-085 consistently increased both the levels of EPA and DHA in the plasma, liver and erythrocyte membranes. After confirming the reduction of plasma total cholesterol, 300mg/kg body weight/day of TAK-085 was continuously administered for another 6 weeks. Supplementation with TAK-085 did not decrease plasma total cholesterol but significantly increased the EPA and DHA levels in both the plasma and liver compared with rats administered atorvastatin only. Supplementation with atorvastatin alone significantly decreased sterol regulatory element-binding protein-1c, Δ5- and Δ6-desaturases, elongase-5, and stearoyl-coenzyme A (CoA) desaturase-2 levels and increased 3-hydroxy-3-methylglutaryl-CoA reductase mRNA expression in the liver compared with control rats. TAK-085 supplementation significantly increased stearoyl-CoA desaturase-2 mRNA expression. These results suggest that long-term supplementation with atorvastatin decreases the EPA and DHA levels by inhibiting the desaturation and elongation of n-3 fatty acid metabolism, while TAK-085 supplementation effectively replenishes this effect in SHRcp rat liver.

An ω-3-enriched diet alone does not attenuate CCl4-induced hepatic fibrosis

Exposure to the halogenated hydrocarbon carbon tetrachloride (CCl4) leads to hepatic lipid peroxidation, inflammation and fibrosis. Dietary supplementation of ω-3 fatty acids has been increasingly advocated as being generally anti-inflammatory, though its effect in models of liver fibrosis is mixed. This raises the question of whether diets high in ω-3 fatty acids will result in a greater sensitivity or resistance to liver fibrosis as a result of environmental toxicants like CCl4. In this study, we fed CCl4-treated mice a high ω-3 diet (using a mix of docosahexaenoic acid and eicosapentaenoic acid ethyl esters). We also co-administered an inhibitor of soluble epoxide hydrolase, 1-trifluoromethoxyphenyl-3-(1-propionylpiperidin-4-yl) urea (TPPU), which has been shown to boost anti-inflammatory epoxy fatty acids that are produced from both ω-3 and ω-6 dietary lipids. We showed that soluble epoxide inhibitors reduced CCl4-induced liver fibrosis. Three major results were obtained. First, the ω-3-enriched diet did not attenuate CCl4-induced liver fibrosis as judged by collagen deposition and collagen mRNA expression. Second, the ω-3-enriched diet raised hepatic tissue levels of several inflammatory lipoxygenase metabolites and prostaglandins, including PGE2. Third, treatment with TPPU in drinking water in conjunction with the ω-3-enriched diet resulted in a reduction in liver fibrosis compared to all other groups. Taken together, these results indicate that dietary ω-3 supplementation alone did not attenuate CCl4-induced liver fibrosis. Additionally, oxylipin signaling molecules may play role in the CCl4-induced liver fibrosis in the high ω-3 diet groups.

Highly Cross-Linked Epoxy Nanofiltration Membranes for the Separation of Organic Chemicals and Fish Oil Ethyl Esters

Membrane separations are highly desired for the chemical industry because they are inexpensive, avoid the use of heat, can be applied to the purification of a wide range of chemicals, and can be scaled to industrial levels. Separating chemicals with molecular weights between 100 and 300 g mol(-1) remains a significant challenge in the field of organic solvent nanofiltration (OSN) due to their similar sizes and rotational flexibility. In this work, we report the fabrication of poly(epoxy) membranes that show excellent selectivity of over 100:1 for chemicals in this range. The membranes are easily tuned to obtain different flux and selectivity by using interchangeable amine and epoxide monomers. These membranes were used to separate the important nutritional omega-3 fatty acid ethyl esters eicosapentaenoic ethyl ester (EPA-EE) and docosahexaenoic acid ethyl ester (DHA-EE) from each other, despite a small difference in molecular weight (26 g mol(-1)). This is the first example of a separation of EPA-EE and DHA-EE using a membrane process.

Kinetics of docosahexaenoic acid ethyl ester accumulation in dog plasma and brain

This study explores dog plasma and brain fatty acid composition achieved after long-term supplementation at high DHA doses. A 90% concentrate of DHA Ethyl Ester (DHA-EE) administered by oral gavage to Beagle dogs at doses of 100, 500, 1000, and 2000mg/kg bw/day for 8 weeks resulted in DHA increases in both plasma and brain. In a subsequent 9-month study, DHA-EE was administered at 150, 1000 and 2000mg/kg bw/day. Plasma DHA increased between 150 and 1000mg/kg bw/day but not between 1000 and 2000mg/kg bw/day and there were increases from Day 1to 92 but not between days 92 and 273. Doses >500mg/kg bw/day in the 8-week and all doses in the 9-month study resulted in DHA increases in the brain. The dose of 150mg/k gbw/day is sufficient to achieve maximal brain concentrations if DHA is administered chronically. For shorter than 6 months of supplementation, higher doses are required.

Synthesis of sn-2 docosahexaenoyl monoacylglycerol by mild enzymatic transesterification of docosahexaenoic acid ethyl ester and glycerol in a solvent-free system

The enzymatic transesterification of docosahexaenoic acid (DHA) ethyl ester with glycerol was performed with several lipases in a solvent-free system and it involves the initial formation of sn-2 docosahexaenyl monoacylglyceride. This DHA derivative is highly relevant for improving the bioavailability of DHA and it has received increasing interest in the field of nutrition. Three commercial lipases, from Rhizomucor miehei (RML), Alcaligenes sp (QL), and Candida antarctica-fraction B (CALB) were tested. In certain cases (CALB), using an excess of DHA ethyl ester and high temperatures the transesterification reaction continues to the formation of triacylglycerides, but in other cases, sn-2 monoacylglyceride (2-MG) is the unique synthetic product even in the presence of high concentrations of DHA ethyl ester. At low temperatures (e.g. 37°C), RML derivatives synthesize only 2-MG in 15 min. These very mild conditions are very interesting for the thermal oxidative stability of the omega-3 fatty acid and for the thermal stability of the biocatalyst. Using Normal Phase HPLC-ELSD and accurate markers, the formation of the 2-MG was confirmed.

Safety of docosahexaenoic acid (DHA) administered as DHA ethyl ester in a 9-month toxicity study in dogs

DHA Ethyl Ester (DHA-EE) is a 90% concentrated ethyl ester of docosahexaenoic acid manufactured from the microalgal oil. The objective of the 9-month study was to evaluate safety of DHA-EE administered to beagle dogs at dose levels 150, 1000 and 2000 mg/kg bw/day by oral gavage and to determine reversibility of any findings after a 2-month recovery period. DHA-EE was well tolerated at all doses. There were observations of dry flaky skin with occasional reddened areas at doses ≥1000 mg/kg bw/day. These findings lacked any microscopic correlate and were no longer present after the recovery period. There were no toxicologically relevant findings in body weights, body weight gains, food consumption, ophthalmological examinations, and ECG measurements. Test article-related changes in hematology parameters were limited to decreases in reticulocyte count in the high-dose males and considered non-adverse. In clinical chemistry parameters, dose-related decreases in cholesterol and triglycerides levels were observed at all doses in males and females and attributed to the known lipid-lowering effects of DHA. There were no effects on other clinical chemistry, urinalysis or coagulation parameters. There were no abnormal histopathology findings attributed to test article. The No-Observable-Adverse-Effect Level of DHA-EE was established at 2000 mg/kg bw/day for both genders.

Effect of oral administration of DHA on the remodeling of calcium handling proteins in congestive heart failure in male rats

Calcium (Ca2+) cycling is essential in cardiac contractile function, and remodeling of calcium handling is thought to be one of the factors contributing to the dysfunction in heart failure (HF). This study investigated the effect of DHA administration on remodeling of Ca2+handling proteins in congestive heart failure (CHF). Male rats were divided into 4 groups (n=8 for each group): C (normal, administered saline); D (normal, administered DHA‐ethyl ester (DHA‐Et)); H (CHF, administered saline); HD (CHF, administered DHA‐Et). CHF was produced by injection of monocrotaline (MCT) into 5‐week‐old rats. Starting from 3 days before MCT injection, saline or DHA‐Et wasorally administered(1g/kg body weight) daily. The right ventriclewas removed on day 24, and quantitative PCR was used to measure the expression of transcripts.The expression of sarcoplasmic reticulum Ca2+‐ATPase (SERCA) 2a, which is responsible to transport back Ca2+ to sarcoplasmic reticulum (SR), was significantly decreased in group H compared to groups C, D and HD (P 蠄 0.05). The expression of ryanodine receptor (RYR) 3, which releases Ca2+ from SR, in group H was significantly increased compared to groups C and D (P 蠄 0.05), and also tended to be increased in group H compared to group HD (P=0.06).The expression of Cav1.2, a component of L‐type Ca2+ channel,was significantly decreased in group H compared to groups C and D (P 蠄 0.05). Remodeling of intracellular Ca2+ handling may be caused by these changes in gene expression in CHF. Administration of DHA‐Et may improve abnormal Ca2+ handling through recovery of the expression of these proteins.

N-3 fatty acids effectively improve the reference memory-related learning ability associated with increased brain docosahexaenoic acid-derived docosanoids in aged rats

We investigated whether a highly purified eicosapentaenoic acid (EPA) and a concentrated n-3 fatty acid formulation (prescription TAK-085) containing EPA and docosahexaenoic acid (DHA) ethyl ester could improve the learning ability of aged rats and whether this specific outcome had any relation with the brain levels of EPA-derived eicosanoids and DHA-derived docosanoids. The rats were tested for reference memory errors (RMEs) and working memory errors (WMEs) in an eight-arm radial maze. Fatty acid compositions were analyzed by GC, whereas brain eicosanoid/docosanoids were measured by LC–ESI-MS–MS-based analysis. The levels of lipid peroxides (LPOs) were measured by thiobarbituric acid reactive substances. The administration of TAK-085 at 300mg·kg−1day−1 for 17weeks reduced the number of RMEs in aged rats compared with that in the control rats. Both TAK-085 and EPA administration increased plasma EPA and DHA levels in aged rats, with concurrent increases in DHA and decreases in arachidonic acid in the corticohippocampal brain tissues. TAK-085 administration significantly increased the formation of EPA-derived 5-HETE and DHA-derived 7-, 10-, and 17-HDoHE, PD1, RvD1, and RvD2. ARA-derived PGE2, PGD2, and PGF2α significantly decreased in TAK-085-treated rats. DHA-derived mediators demonstrated a significantly negative correlation with the number of RMEs, whereas EPA-derived mediators did not exhibit any relationship. Furthermore, compared with the control rats, the levels of LPO in the plasma, cerebral cortex, and hippocampus were significantly reduced in TAK-085-treated rats. The findings of the present study suggest that long-term EPA+DHA administration may be a possible preventative strategy against age-related cognitive decline.

N-3 PUFA induce microvascular protective changes during ischemia/reperfusion.

Ischemia/reperfusion (I/R) injury can occur in consequence of myocardial infarction, stroke and multiple organ failure, the most prevalent cause of death in critically ill patients. I/R injury encompass impairment of endothelial dependent relaxation, increase in macromolecular permeability and leukocyte-endothelium interactions. Polyunsaturated fatty acids (n-3 PUFA), such as eicosapentaenoic acid (EPA, 20:5n-3) and docosahexaenoic acid (DHA, 22:6n-3) found in fish oil have several anti-inflammatory properties and their potential benefits against I/R injury were investigated using the hamster cheek pouch preparation before and after ischemia. Before the experiments, hamsters were treated orally with saline, olive oil, fish oil and triacylglycerol (TAG) and ethyl ester (EE) forms of EPA and DHA at different daily doses for 14 days. Fish oil restored the arteriolar diameter to pre ischemic values during reperfusion. At onset and during reperfusion, Fish oil and DHA TAG significantly reduced the number of rolling leukocytes compared to saline and olive oil treatments. Fish oil, EPA TAG and DHA TAG significantly prevented the rise on leukocyte adhesion compared to saline. Fish oil (44.83 ± 3.02 leaks/cm2), EPA TAG (31.67 ± 2.65 leaks/cm2), DHA TAG (41.14 ± 3.63 leaks/cm2), and EPA EE (30.63 ± 2.25 leaks/cm2), but not DHA EE (73.17 ± 2.82 leaks/cm2) prevented the increase in macromolecular permeability compared to saline and olive oil (134.80 ± 1.49 and 121.00 ± 4.93 leaks/cm2, respectively). On the basis of our findings, we may conclude that consumption of n-3 polyunsaturated fatty acids, especially in the triacylglycerol form, could be a promising therapy to prevent microvascular damage induced by ischemia/reperfusion and its consequent clinical sequelae.

Oxidative stability of DHA phenolic ester

Docosahexaenoic acid vanillyl ester (DHA-VE) was synthesized from docosahexaenoic acid ethyl ester (DHA-EE) and vanillyl alcohol by a solvent-free alcoholysis process catalysed by Candida antarctica lipase B. Oxidative stability of pure DHA-VE and the crude reaction medium consisting of 45% DHA-VE and 55% DHA-EE were compared with that of DHA-EE under various storage conditions. Oxidation progress was followed by determination of conjugated dienes and FTIR measurements. Analyses showed that DHA-EE was rapidly oxidised under all storage conditions in comparison with DHA-VE and crude reaction medium, whatever the temperature and the storage time. The grafting of vanillyl alcohol appeared as a powerful way to stabilize DHA against oxidation. Thanks to their stability, both DHA-VE and the crude reaction medium, allowing the production of the ester, offer huge potential as functional ingredients.

Eicosapentaenoic and docosahexaenoic acid ethyl esters differentially enhance B-cell activity in murine obesity

EPA and DHA are not biologically equivalent; however, their individual activity on B cells is unknown. We previously reported fish oil enhanced murine B-cell activity in obesity. To distinguish between the effects of EPA and DHA, we studied the ethyl esters of EPA and DHA on murine B-cell function as a function of time. We first demonstrate that EPA and DHA maintained the obese phenotype, with no improvements in fat mass, adipose inflammatory cytokines, fasting insulin, or glucose clearance. We then tested the hypothesis that EPA and DHA would increase the frequency of splenic B cells. EPA and DHA differentially enhanced the frequency and/or percentage of select B-cell subsets, correlating with increased natural serum IgM and cecal IgA. We next determined the activities of EPA and DHA on ex vivo production of cytokines upon lipopolysaccharide stimulation of B cells. EPA and DHA, in a time-dependent manner, enhanced B-cell cytokines with DHA notably increasing IL-10. At the molecular level, EPA and DHA differentially enhanced the formation of ordered microdomains but had no effect on Toll-like receptor 4 mobility. Overall, the results establish differential effects of EPA and DHA in a time-dependent manner on B-cell activity in obesity, which has implications for future clinical studies.

1. Daily DHA injections raise seizure thresholds and blood but not brain free DHA levels in rats

Background Docosahexaenoic acid (DHA) is an omega-3 polyunsaturated fatty acid (n−3 PUFA), which has previously shown to have anticonvulsant activity rats. The purpose of the present experiment was: (1) to confirm that sub-chronic DHA raises thresholds in the maximal pentylenetetrazole (PTZ) model, and (2) to determine whether that increase is correlated with an increase in serum and brain DHA Methods Animals received daily i.p. injections of 50 mg/kg of DHA, 50 mg/kg DHA ethyl ester (DHA EE) or volume-matched vehicle for 14 days. On day 15, one group of animals was seizure tested in the maximal PTZ model, while another group provided blood and brain samples. Brain samples were obtained after the animals were euthanized via head-focused microwave fixation. Lipid analyses were performed on both blood and brain. Since the DHA and DHA EE groups did not differ significantly, they were combined for statistical analyses. Results In the maximal PTZ model, DHA significantly increased seizure latency by approximately 3 fold, as compared to vehicle-injected controls. This increase in seizure latency was associated with an increase in serum unesterified DHA levels. Total brain DHA and brain unesterified DHA, however, were not significantly different between treatment and control groups.

Effect of orally administered EPA and DHA on congestive heart failure in rat (831.7)

This study assessed the effect of EPA and DHA on congestive heart failure (CHF) in rat. Four‐week‐old male rats were divided into 4 groups: C (normal, administered saline, n=4‐5); H (with CHF, administered saline, n=10‐11); HE (with CHF, administered EPA‐ethyl ester (EPA‐Et), n=9‐10); and HD (with CHF, administered DHA‐ethyl ester (DHA‐Et), n=10). CHF was produced by subcutaneous injection of monocrotaline (MCT) into 5‐week‐old rats. Starting from 3 days before MCT injection, rats were orally administered (1g/kg body weight) saline or one of the two fatty acids daily, anaesthetized on day 24, their electrocardiograms (ECGs) recorded, serum samples drawn, and then killed. The heart was removed, and kept at ‐80ºC or fixed with paraformaldehyde. Fatty acid levels in the heart and triglycerides in serum were determined. Pathological assessment was performed on heart tissue. The Q and T waves (QT) interval on ECG was significantly shorter (P 蠄 0.05) in C and HD groups than in H and HE groups. In the heart, EPA level was higher in HE group and DHA level higher in C and HD groups, compared to H group (P 蠄 0.05). Triglyceride level was significantly decreased (P 蠄 0.05) in H, HE and HD groups compared to C group. In HD group, mononuclear cells tended to infiltrate less into myocytes than in H group (P = 0.06). The right ventricle weighed significantly more (P 蠄 0.05) in H, HE and HD groups compared to C group. The mean survival rate in the three experiments was 100% for C group, 74% for H group, 65% for HE group and 70% for HD group. Administration of EPA‐Et or DHA‐Et may affect cardiac function through alteration of heart fatty acid composition. Furthermore, DHA‐Et administration may contribute to ameliorating CHF.Grant Funding Source: Supported by JSPS KAKENHI Grant Number 21500788

EPA and DHA increase the frequency of murine B cell subsets and restore antibody production in obesity upon stimulation with a T‐independent antigen (382.5)

Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), the bioactive components of fish oil, exert immunomodulatory properties. The impact of EPA and DHA supplementation on murine B cell function is poorly studied. We first determined the effects of fish oil on B cell phenotypes and antibody production in obese mice upon stimulation with a T‐independent antigen. Fish oil intervention increased the frequency of transitional 1 and marginal zone B cells in obese mice. Fish oil restored the decrement in circulating IgM in obesity and increased antibody production in lean mice. We then measured the effects of EPA and DHA ethyl esters on B cell activation upon supplementation to an obesogenic diet. Ex vivo stimulation of B cells with lipopolysaccharide increased B cell activation as measured by TNF‐α and IL‐6 secretion. DHA, but not EPA, increased B cell IL‐10 production. In vivo, EPA and DHA differentially increased the frequency of transitional 1, transitional 2 and pre‐marginal zone cells. Taken together, the data establish that fish oil can boost B‐cell mediated immunity in obesity and that EPA and DHA ethyl esters exert differential effects on B cells.

Oral Administration of Eicosapentaenoic Acid or Docosahexaenoic Acid Modifies Cardiac Function and Ameliorates Congestive Heart Failure in Male Rats1–3

This study assessed the effects of eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA) on normal cardiac function (part 1) and congestive heart failure (CHF) (part 2) through electrocardiogram analysis and determination of EPA, DHA, and arachidonic acid (AA) concentrations in rat hearts. In part 2, pathologic assessments were also performed. For part 1 of this study, 4-wk-old male rats were divided into a control group and 2 experimental groups. The rats daily were orally administered (1 g/kg body weight) saline, EPA–ethyl ester (EPA-Et; E group), or DHA–ethyl ester (DHA-Et; D group), respectively, for 28 d. ECGs revealed that QT intervals were significantly shorter for groups E and D compared with the control group (P ≤ 0.05). Relative to the control group, the concentration of EPA was higher in the E group and concentrations of EPA and DHA were higher in the D group, although AA concentrations were lower (P ≤ 0.05). In part 2, CHF was produced by subcutaneous injection of monocrotaline into 5-wk-old rats. At 3 d before monocrotaline injection, rats were administered either saline, EPA-Et, or DHA-Et as mentioned above and then killed at 21 d. The study groups were as follows: normal + saline (control), CHF + saline (H group), CHF + EPA-Et (HE group), and CHF + DHA-Et (HD group). QT intervals were significantly shorter (P ≤ 0.05) in the control and HD groups compared with the H and HE groups. Relative to the H group, concentrations of EPA were higher in the HE group and those of DHA were higher in the control and HD groups (P ≤ 0.05). There was less mononuclear cell infiltration in the myocytes of the HD group than in the H group (P = 0.06). The right ventricles in the H, HE, and HD groups showed significantly increased weights (P ≤ 0.05) compared with controls. The administration of EPA-Et or DHA-Et may affect cardiac function by modification of heart fatty acid composition, and the administration of DHA-Et may ameliorate CHF.