Docosahexaenoic Acid Ethyl Ester Research Articles

Fast Molecular Recognition of Docosahexaenoic Acid Ethyl Ester in the Liver and Meat of Stingray Using a Miniplatform Based on a 3D Stochastic Microsensor

Docosahexaenoic acid ethyl ester has an important role in the prevention of the neuropsychiatric and neurodegenerative diseases. Its extraction from fish such as the stingray as anoil creates a pharmaceutical formulation. Therefore it is essential to develop fast molecular recognition methods able to perform both qualitative and quantitative determination of docosahexaenoic in stingray meat and liver. A miniplatform incorporating a 3D stochastic microsensor was designed and validated for the molecular recognition of docosahexaenoic acid ethyl ester. The design of the microsensor was based on the modification of a graphene decorated with nitrogen and boron paste (NB-graphene paste) with 10−3mol L−1 alpha-cyclodextrin. A wide linear concentration range (5.0 × 10−14 − 5.0 × 10−7 g mL−1) and a low limit of quantitation (5.0 × 10−14 g mL−1) were obtained. High recovery values were determined when the miniplatform was used for the assay of docosahexaenoic acid ethyl ester from stingray liver and meat with recoveries higher than 99.20%. The relative standard deviation values were less than 0.05 (N = 10).

Plasma levels of EPA and DHA after ingestion of a single dose of EPA and DHA ethyl esters

AbstractOmega‐3 polyunsaturated fatty acids (n3 PUFA), specifically eicosapentaenoic acid (EPA, 20:5n3), and docosahexaenoic acid (DHA, 22:6n3), are essential for maintaining health. To better understand their biology, it is important to define their bioavailability. The aim of this cross‐over study was to investigate and compare the acute effects on plasma EPA and DHA levels after single doses of EPA oil (99% pure) and DHA (97% pure) ethyl esters. Twelve men aged 20–40 years with a body‐mass‐index of 20–27 kg/m2 and low fish consumption were recruited. Several measures (e.g., 4‐week run‐in period, standardized diet, and blood collection protocols) were taken to reduce the inter‐individual variability of plasma fatty acids levels. Using a cross‐over design, the subjects received 2.2 g of EPA in the first test period and 2.3 g of DHA in the second. The test periods were separated by 2 weeks. Blood samples were taken before dosing and after 2, 4, 6, 8, 12, 24, 48, and 72 h. The mean ± SE maximum concentrations for EPA were higher than for DHA (115 ± 11 μg/mL vs. 86 ± 12 μg/mL; p = 0.05). The mean ± SE incremented area under the plasma concentration curve over 72 h for EPA (2461 ± 279 μg/mL) was 2.4 times higher (p < 0.001) than that for DHA (1021 ± 170 μg/mL). The mean ± SE half‐life was for EPA and DHA was 45 ± 8 and 66 ± 12 h. Our results indicate that EPA administration in single doses leads to higher circulating plasma levels of EPA compared to an effect of an equivalent dose of DHA on DHA plasma levels.

The effect of vitamin E and docosahexaenoic acid ethyl ester on Metabolic Dysfunction-Associated steatotic Liver Disease (MASLD)-A randomised, double-blind, placebo-controlled, parallel-group clinical trial (PUVENAFLD).

We conducted a clinical trial to determine the efficacy of the combination of vitamin E and/or docosahexaenoic acid (DHA) versus placebo in reducing liver fat content after 6 months of intervention in adults with MASLD. Adults with MASLD were randomised to one of four treatment arms (vitamin E 1000 mg/daily + DHA 1.89 g/daily or combination arm, vitamin E 1000 mg alone, DHA 1.89 g alone or placebo) following a 2:1:1:2 randomisation. The primary objective was to determine the efficacy of DHA + vitamin E versus placebo in reducing hepatic fat fraction (%) relative to baseline after 6 months of intervention. Secondary objectives were to determine the effect of vitamin E or DHA alone versus placebo on reducing liver fat at 6 months. Our cohort consisted of 203 subjects with a mean age of 51 years, 53% female, 91% White, 59% Hispanic ethnicity. The combination of vitamin E + DHA had no effect on the primary endpoint of reducing hepatic steatosis as determined by MRI-PDFF (p = 0.98). Neither vitamin E alone (p = 0.91) nor DHA alone (p = 0.14) significantly reduced hepatic steatosis compared to placebo. However, the trial was not powered adequately for this analysis. Compared with placebo, no statistically significant differences were detected in the 3-month or 6-month levels for ALT (U/L) or AST (U/L) in all three intervention groups. The combination of DHA + vitamin E or either agent alone did not demonstrate efficacy on reducing liver fat or aminotransferases in the studied population.

Binding modes of the metabolites docosahexaenoic acid, eicosapentaenoic acid, and eicosapentaenoic acid ethyl ester from Caulerpa racemosa as COX-2 inhibitors revealed via metabolomics and molecular dynamics

A total of 116 metabolites of Caulerpa racemosa were identified. However, only three (DHA, EPA, and EPAS) were found to have high anti-inflammatory potential, with Pa scores ranging from 0.764 to 0,827. The inhibition constant (Ki) and binding energy interactions with COX-2 revealed by DHA (−8.83 kcal/mol: 0.338 μM), EPA (−8.35 kcal/mol: 0.763 μM), EPAS (−8.05 kcal/mol: 1.25 μM). They were used to bind to the fundamental residues of COX-2 (TYR 348, VAL 349, LEU 384, TYR 385, and TRP 387). The result of molecular dynamics showed that DHA, EPA, and EPAS had high stability while interacting with COX-2 in 310 K. The stabilities were 1.8 Å for DHA from 60 Ns to 200 Ns, 2.0 Å for EPA from 75 Ns to 200 Ns, and 2.2 Å for EPAS from 100 Ns to 200 Ns. Additionally, the potential energy of DHA (−1.069.250 eV) was higher compared with that of EPA (−1.069.247 eV) and EPAS (−1.069.220 eV). This data shows that DHA, EPA, and EPAS could stably inhibit COX-2 by blocking the transcriptional regulation of COX-2 via TYR348, VAL349, LEU384, TYR385, and TRP387.

Preparation of High-Purity Docosahexaenoic Acid Ethyl Ester from Algal Oil through Enzymatic Ethanolysis.

Docosahexaenoic acid plays a crucial role in infant brain function, and the market demand of high-purity docosahexaenoic acid is continuously increasing. The availability of docosahexaenoic acid in natural fish oil is limited, prompting the exploration of alternative sources like microalgae. For algal oil, enzymatic ethanolysis is preferred to chemical methods because the former is milder and can avoid docosahexaenoic acid oxidation. However, enzymatic methods have generally low yield due to the poor substrate-specificity of lipase to long-chain polyunsaturated fatty acids, affecting the yield and purity of docosahexaenoic acid. Therefore, we developed an efficient process to produce high-purity docosahexaenoic acid ethyl ester from algal oil, by screening lipases, optimizing enzymatic ethanolysis and applying molecular distillation. Lipase UM1 was the best lipase to produce ethyl ester from algal oil with the highest ethyl ester yield (95.41%). Meanwhile, it was a catalyst for the reaction of long-chain polyunsaturated fatty acids with ethanol. The fatty acid docosahexaenoic acid conversion rates exceeded 90%. After molecular distillation, a final product containing 96.52% ethyl ester was obtained with a docosahexaenoic acid content up to 80.11%. Our findings provide an highly effective enzymatic method for the production of high-purity docosahexaenoic acid ethyl esters, with potential commercial applications.

A randomized double-blind trial to measure the absorption characteristics of eicosapentaenoic acid and docosahexaenoic acid rich oil blend with natural lipid-based delivery system.

A randomized, double-blinded trial with 65 subjects was conducted to compare the pharmacokinetics between PhytoMarineCelle (PM) that consists of eicosapentaenoic acid and docosahexaenoic acid (EPA + DHA) plus a self-emulsifying drug delivery system (SEDDS), and a standard EPA + DHA ethyl ester (SEE) that does not contain SEDDS. PM showed 1.6-fold greater plasma area under the curve (AUC) than SEE at 300 mg, although no significant difference was observed. PM showed a 3.1 and 3.2-fold (p < 0.05) greater plasma AUC than SEE at 500 mg and 1000 mg respectively. The concentration max (Cmax) of EPA + DHA did not change between PM and SEE at 300 mg. Cmax of PM was twofold greater than SEE at 500 mg and 1000 mg respectively. The Cmax of EPA + DHA achieved significant difference (p < 0.05) only with the 500 mg dose. The PM formulation increased the bioavailability of EPA + DHA by threefold compared to SEE at 500 and 1000 mg.

Blood and tissue docosahexaenoic acid (DHA, 22:6n-3) turnover rates from Ahiflower® oil are not different than from DHA ethyl ester oil in a diet switch mouse model

Ahiflower® oil is high in α-linolenic and stearidonic acids, however, tissue/blood docosahexaenoic acid (DHA, 22:6n-3) turnover from dietary Ahiflower oil has not been investigated. In this study, we use compound-specific isotope analysis to determine tissue DHA synthesis/turnover from Ahiflower, flaxseed and DHA oils. Pregnant BALB/c mice (13–17 days) were placed on a 2 % algal DHA oil diet of high carbon-13 content (δ13C) and pups (n = 132) were maintained on the diet until 9 weeks old. Mice were then randomly allocated to a low δ13C-n-3 PUFA diet of either: 1) 4 % Ahiflower oil, 2) 4.35 % flaxseed oil or 3) 1 % fish DHA ethyl ester oil for 1, 3, 7, 14, 30, 60 or 120 days (n = 6). Serum, liver, adipose and brains were collected and DHA levels and δ13C were determined. DHA concentrations were highest (p < 0.05) in the liver and adipose of DHA-fed animals with no diet differences in serum or brain (p > 0.05). Based on the presence or absence of overlapping 95 % C.I.'s, DHA half-lives and synthesis/turnover rates were not different between Ahiflower and DHA diets in the liver, adipose or brain. DHA half-lives and synthesis/turnover rates from flaxseed oil were significantly slower than from the DHA diet in all serum/tissues. These findings suggest that the distinct Ahiflower oil n-3 PUFA composition could support tissue DHA needs at a similar rate to dietary DHA, making it a unique plant-based dietary option for maintaining DHA turnover comparably to dietary DHA.

Omega-3 Fatty Acids Inhibit Endoplasmic Reticulum (ER) Stress in Human Coronary Artery Endothelial Cells

The biological effects of fatty acids differ by their structure. Saturated fatty acids and trans-fatty acids are recognized as promoters of coronary artery disease (CAD), while monounsaturated and omega-3 fatty acids may have salutary effects. Since cellular stress is recognized as a fundamental driver of CAD, the effect of these fatty acids on endoplasmic reticulum (ER) stress in human coronary artery endothelial cells (HCAECs) was measured using the ER stress-responsive alkaline phosphatase (ES-TRAP) assay. Docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), and eicosapentaenoic acid ethyl ester (EPA-EE) suppressed ER stress induced with pharmacologic (tunicamycin) and physiologic (high-dextrose concentration) ER stress inducers. In tunicamycin-treated cells, DHA reduced the expression of unfolded protein response (UPR) markers such as phosphorylation of inositol requiring enzyme 1α (IRE1α) and protein kinase R-like endoplasmic reticulum kinase (PERK) and increased activating transcription factor 6 (ATF6) and glucose regulated protein 78 (GRP78) expression. Similarly, treatment with both oleic acid and arachidonic acid, but not elaidic acid (a trans-fatty acid), suppressed both tunicamycin and high-dextrose-induced ER stress while treatment with saturated fatty acids (C14 : 0, C16 : 0, and C18 : 0) enhanced both tunicamycin and high-dextrose-induced ER stress. The latter fatty acids at higher concentrations caused cytotoxicity. These results indicate that omega-3 fatty acids as well as select unsaturated fatty acids and arachidonic acid suppress ER stress in HCAEC.

Storage Duration and Added Docosahexaenoic Acid Modify the Rates of Esterified and Free Oxylipin Formation in Infant Milk Formula

Infant milk formulas often contain docosahexaenoic acid (DHA), a highly unsaturated fatty acid that is prone to oxidation. Previously, we reported in oil that the esterified lipid pool is more prone to lipid oxidation than the free pool. However, it is unknown whether added DHA modifies lipid oxidation in infant formula. In the present study, we quantified lipid oxidation rates in infant milk formula containing canola oil (F1) or canola oil supplemented with DHA-ethyl ester (F2). Lipid oxidation kinetics were determined by quantifying esterified and free oxylipins using liquid chromatography-tandem mass spectrometry (LC-MS/MS) during storage for 21 days at 4 °C. Esterified oxylipins increased in concentration within 3 and 7 days of storage in F2 (with DHA) and F1, respectively. Free oxylipins appeared 7 and 14 days later in F2 and F1, respectively. The kinetic estimates revealed that esterified oxylipins formed at a faster rate in both formulas compared to free oxylipins. Surprisingly, in F2 (which contains DHA), the rates of formation of both esterified and free linoleic acid and alpha-linolenic acid-derived oxylipins were higher than in F1. This study demonstrated that in food systems, DHA promotes the oxidation of other PUFAs, and that triacylglycerol/esterified lipids are preferentially oxidized over free fatty acids, highlighting the role of triacylglycerols in lipid oxidation.

Determination and evaluation of EPA and DHA ethyl esters in fish oils using the TMAH transesterification method

Determination and evaluation of EPA and DHA ethyl esters in fish oils using the TMAH transesterification method

The Formation of Diradylglycerol Molecular Species in Murine Peritoneal Macrophages Varies Dose-Dependently with Dietary Purified Eicosapentaenoic and Docosahexaenoic Ethyl Esters

Substantial effects of dietary fish oil-derived fatty acid ethyl esters on the metabolism of diradylglycerol (DG) have recently been described. We undertook to isolate the separate effects of (n-3) eicosapentaenoic acid (EPA) and (n-3) docosahexaenoic acid (DHA) on DG metabolism. For 3 wk, male C57BL/6 mice were fed one of six purified diets in which the lipid component was either 3 g/100 g corn oil ethyl ester (COEE) (control diet) or 1 g/100 g COEE plus 2 g/100 g of EPA ethyl ester (EPEE), DHA ethyl ester (DHEE) or an EPEE:DHEE mixture. Peritoneal macrophages were analyzed for DG content and for molecular species distributions of DG and phospholipid classes. We found that the degree of incorporation of EPA and DHA into DG in macrophages was dependent on the dietary concentration of EPEE and DHEE, under basal conditions and after stimulation with platelet-activating factor, phorbol myristate acetate and ionomycin. Incorporation of EPA and DHA into phospholipids was also significant and dose dependent in each phospholipid class. For both DG and phospholipid molecular species, the incorporation of EPA in the sn-2 position was considerably greater than that of species with DHA under conditions of equimolar dietary content. These results demonstrate that 1) incorporation of EPA and DHA into DG are independent and dependent on dietary content, 2) EPA is incorporated with greater affinity than DHA and 3) these effects on DG metabolism seem to result from corresponding effects on parent membrane phospholipids. Physiologically and therapeutically relevant differences may exist between EPA and DHA.

Early detection of lipid oxidation in infant milk formula by measuring free oxylipins-Comparison with hydroperoxide value and thiobarbituric acid reactive substance methods.

Infant milk formula was used as a model food to compare the sensitivity of thiobarbituric acid reactive substances (TBARS) and hydroperoxide methods to UPLC-MS/MS oxylipin analysis for detecting early lipid oxidation. Two different infant milk formulas were tested during 21 days of storage at 4°C. Formulas 1 and 2 contained canola oil and canola oil + 1% docosahexaenoic acid ethyl ester, respectively. Formulas were sampled up to 21 days of storage. Formula 2 had higher peroxide values than Formula 1 across all time points. However, no significant differences over time in TBARS and peroxide values in either formula were observed. Several oxylipins increased in both formulas starting on day 7 (linoleic acid and alpha-linolenic acid-derived oxylipins in Formula 1 and DHA-derived oxylipins in Formula 2). These results indicate that free oxylipins are effective in detecting early lipid oxidation and distinguishing between formulations containing different fatty acids. PRACTICAL APPLICATION: We have recently shown that primary oxidation products known as oxylipins can be measured in their free form by ultra-high pressure liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) to detect early lipid oxidation. However, a head-to-head comparison of the sensitivity of this approach to conventional spectrophotometric methods has not been evaluated. Our results indicate that free oxylipin measurements are better than conventional methods in detecting early lipid oxidation in milk infant formula distinguishing between different formulations.

Multi-omics analysis reveals the host-microbe interactions in aged rhesus macaques.

Aging is a complex multifactorial process that greatly affects animal health. Multi-omics analysis is widely applied in evolutionary biology and biomedical research. However, whether multi-omics can provide sufficient information to reveal comprehensive changes in aged non-human primates remains unclear. Here, we explored changes in host–microbe interactions with aging in Chinese rhesus macaques (Macaca mulatta lasiota, CRs) using multi-omics analysis. Results showed marked changes in the oral and gut microbiomes between young and aged CRs, including significantly reduced probiotic abundance and increased pathogenic bacterial abundance in aged CRs. Notably, the abundance of Lactobacillus, which can metabolize tryptophan to produce aryl hydrocarbon receptor (AhR) ligands, was decreased in aged CRs. Consistently, metabolomics detected a decrease in the plasma levels of AhR ligands. In addition, free fatty acid, acyl carnitine, heparin, 2-(4-hydroxyphenyl) propionic acid, and docosahexaenoic acid ethyl ester levels were increased in aged CRs, which may contribute to abnormal fatty acid metabolism and cardiovascular disease. Transcriptome analysis identified changes in the expression of genes associated with tryptophan metabolism and inflammation. In conclusion, many potential links among different omics were found, suggesting that aged CRs face multiple metabolic problems, immunological disorders, and oral and gut diseases. We determined that tryptophan metabolism is critical for the physiological health of aged CRs. Our findings demonstrate the value of multi-omics analyses in revealing host–microbe interactions in non-human primates and suggest that similar approaches could be applied in evolutionary and ecological research of other species.

Biophysical modeling indicates a high affinity of ethyl esters of omega-3 polyunsaturated fatty acids to the enzymes of the pro-inflammatory arachidonic acid cascade

Background. Omega-3 polyunsaturated fatty acids (ω-3 PUFAs) are widely used in modern cardiology. The anti-inflammatory effect of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) is realized, in particular, by modulating the activity of the arachidonic acid (ARA) cascade.Objective: to conduct biophysical analysis of the interactions of various forms of PUFAs (ARA, EPA, DHA, EPA and DHA ethyl esters) with three target proteins-enzymes of the ARA cascade (cyclooxygenase-1 (COX-1), COX-2, 5-lipoxygenase (5-LPOG)).Material and methods. The minimization of the energy of the ligand-receptor complexes at various initial positions of the molecule relative to the receptor pocket and the molecular energy profiles of the protein (the energy of side chain transfer from solvent to protein) were calculated using the ECMMS package.Results. EPA and DHA ethyl esters were characterized by significantly higher absolute values of specific binding energies of target proteins than ARA or simply EPA/DHA. For example, in the case of COX-2, EPA, DHA and EPA ethyl ester had similar ∆∆G values (–3.0...–3.1 kcal/mol), while the COX-2 complex with DHA ethyl ester was somewhat more stable (∆∆G = –3.4 kcal/mol). In the case of the 5-LPOG enzyme, the complex with EPA ethyl ester was the most stable (∆∆G = –1.62 kcal/mol). Higher absolute binding energies indicate a higher affinity of EPA and DHA ethyl esters to enzymes of the ARA cascade.Conclusion. The results suggest that the high affinity of EPA and DHA ethyl esters to the enzymes of the ARA cascade is one of the molecular bases of therapeutic efficacy of ω-3 PUFAs with high degree of standardization.

Development of certified reference materials for four polyunsaturated fatty acid esters

Certified reference materials (CRMs) with high accuracy and traceability are essential tools for the validation of analytical methods and calibration of equipment. In this study, purity CRMs for four polyunsaturated fatty acids (PUFAs) esters, namely, cis-(4,7,10,13,16,19)- Docosahexaenoic acid methyl ester (DHA-ME), cis-4,7,10,13,16,19- Docosahexaenoic acid ethyl ester (DHA-EE), cis-(5,8,11,14,17)- Eicosapentaenoic acid methyl ester (EPA-ME) and cis-(5,8,11,14,17)- Eicosapentaenoic acid ethyl ester (EPA-EE), were first developed according to the ISO Guide. The CRMs’ purity values were assigned based on the average of quantitative nuclear magnetic resonance and mass balance approaches. The certified value with expanded uncertainties (k = 2, 95% confidence interval) were determined to be (98.8 ± 0.4) %, (99.0 ± 0.3) %, (98.9 ± 0.4) % and (98.9 ± 0.4) % for DHA-ME, DHA-EE, EPA-ME and EPA-EE, respectively. The four PUFAs esters were homogeneous and stable for 12 months at −4 °C and 7 days at 50 °C.

Continuous Production of DHA and EPA Ethyl Esters via Lipase-Catalyzed Transesterification in an Ultrasonic Packed-Bed Bioreactor

Ethyl esters of omega-3 fatty acids are active pharmaceutical ingredients used for the reduction in triglycerides in the treatment of hyperlipidemia. Herein, an ultrasonic packed-bed bioreactor was developed for continuous production of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) ethyl esters from DHA+EPA concentrate and ethyl acetate (EA) using an immobilized lipase, Novozym® 435, as a biocatalyst. A three-level–two-factor central composite design combined with a response surface methodology (RSM) was employed to evaluate the packed-bed bioreactor with or without ultrasonication on the conversion of DHA + EPA ethyl ester. The highest conversion of 99% was achieved with ultrasonication at the condition of 1 mL min−1 flow rate and 100 mM DHA + EPA concentration. Our results also showed that the ultrasonic packed-bed bioreactor has a higher external mass transfer coefficient and a lower external substrate concentration on the surface of the immobilized enzyme. The effect of ultrasound was also demonstrated by a kinetic model in the batch reaction that the specificity constant (V′max/K2) in the ultrasonic bath was 8.9 times higher than that of the shaking bath, indicating the ultrasonication increased the affinity between enzymes and substrates and, therefore, increasing reaction rate. An experiment performed under the highest conversion conditions showed that the enzyme in the bioreactor remained stable at least for 5 days and maintained a 98% conversion.

Synthesis of DHA-enriched triglyceride through glycerolysis: Process parameters and reuse of partially inactivated lipase

Docosahexaenoic acid (DHA)-enriched triglyceride products are valued by pharmaceutical and health and wellness industry. Enzymatic synthesis is an efficient method for producing DHA-enriched triglyceride. In this presented study, enzymatic synthesis conditions were optimized as follows: molar ratio of DHA ethyl ester (DHA-EE) to glycerol 3:1; lipase loading 6.4% (with respect to the DHA-EE mass); reaction temperature 108 °C; reaction time 13.6 h. Under these conditions, the yield of triglyceride reached 97.00 ± 0.61%. Catalytical activity of lipase reduced to 80% after 10 cycles, which was defined as inactivated lipase. Increasing lipase loading to 8.0% (catalytical activity equal to original lipase) can’t convert DHA-EE to triglyceride. However, DHA triglycerides can be achieved by using 4.0% inactivated lipase plus 3.2% original lipase (catalytical activity equal to original lipase). Analysis of the reaction kinetics showed that inactivated lipase cannot reach the activation energy (47.94 kJ/mol) required for the reaction system, but inactivated lipase plus original lipase can. A triglyceride content of 95.44 ± 0.54% was achieved using 4.0% inactivated lipase plus 3.2% original lipase, which was no significant difference with original lipase. This present study provided a technical solution to reuse the partially inactivated lipase and may reduce the prime cost of producing DHA-enriched triglyceride.

Docosahexaenoic acid monoglyceride induces apoptosis and autophagy in breast cancer cells via lipid peroxidation-mediated endoplasmic reticulum stress.

Epidemiologic and preclinical studieshave shown that marine n-3 polyunsaturated fatty acids (n-3 PUFAs) elicit promising chemoprevention against breast cancer. Docosahexaenoic acid monoglyceride (MAG-DHA), a docosahexaenoic acid sn-1-monoacylglycerol does not required pancreatic lipase to be absorbed, eliciting a better bioavailability when compared with other formulations such as DHA-free fatty acid, DHA-triglycerol, or DHA-ethyl ester. However, the anticancer actions and underlying mechanisms of MAG-DHA on breast cancer remain to be assessed. In this study, MAG-DHA induced significant growth inhibition in MCF-7 and MDA-MB-231 breast cancer cells in a dose-dependent manner. MAG-DHA treatment (80 µM) led to 83.8 and 94.3% growth inhibition between MCF-7 and MDA-MB-231 cells, respectively. MAG-DHA-induced growth inhibition was tightly associated with apoptosis, as evidenced by increased active forms of caspase-3, poly (ADP-ribose) polymerase (PARP) and caspase-12. In particular, MAG-DHA-induced apoptosis was triggered by oxidative stress-mediated endoplasmic reticulum (ER) stress, as evidenced by activation of the PERK-eIF2α pathway in ER. MAG-DHA treatment also strongly suppressed the growth of E0771 murine breast cancer xenografts, significant differences of tumor volume were found between MAG-DHA group (0.271 cm3 ) and control group (0.875 cm3 ) after 15 daily MAG-DHA treatments. The in vitro antibreast cancer mechanism of MAG-DHA was supported by the in vivo xenograft model. In addition, MAG-DHA-induced ER stress concomitantly triggered autophagy in these cancer cells, and the induction of autophagy suppressed its ability to induce apoptotic cell death. Our data suggested that MAG-DHA as dietary supplement, in combination with autophagy inhibitors may be a useful therapeutic strategy in treating breast cancer.

Comparative Study of DHA with Different Molecular Forms for Ameliorating Osteoporosis by Promoting Chondrocyte-to-Osteoblast Transdifferentiation in the Growth Plate of Ovariectomized Mice.

Osteoblasts play a key role in bone remodeling. Recent studies have reported that some hypertrophic chondrocytes co-expressing collagen I(Col I) and collagen X (ColX) could directly transdifferentiate into osteoblasts during endochondral ossification. However, whether nutrition intervention is beneficial to this transformation to improve osteoporosis (OP) remains unknown. In this study, ovariectomy (OVX)-induced OP mice were orally administered with docosahexaenoic acid (DHA) in different molecular forms for 13 weeks. The results showed that both DHA-triglyceride (DHA-TG) and DHA-phosphatidylcholine (DHA-PC) increased the bone mineral density and bone mineral apposition rate in ovariectomized mice, while DHA-ethyl esters (DHA-EE) had little effect. Interestingly, we found that both DHA-PC and DHA-TG increased the height of the growth plate, mainly increasing the number of hypertrophic chondrocytes. Further investigation by simultaneously labeling ColX and ColI indicated that DHA-PC and DHA-TG promoted the number of chondrocyte-transdifferentiated osteoblasts in the growth plate close to the diaphysis, in which DHA-PC performed better than DHA-TG. Apoptosis was not the only fate of hypertrophic chondrocytes. Western blot results showed that both DHA-TG and DHA-PC downregulated the Bax and cleaved-caspase3 expression and upregulated Bcl-2 expression in the growth plate, suggesting that chondrocyte apoptosis is inhibited. Runx2, the key regulator of chondrocyte-to-osteoblast transdifferentiation, was significantly increased by DHA-TG and DHA-PC, while DHA-EE had no effect on the above indicators. To our best knowledge, this is the first report that both DHA-PC and DHA-TG enhanced bone formation via promoting the chondrocyte-to-osteoblast transdifferentiation in the growth plate, contributing to the amelioration of OP. These activities depend on the molecular forms of DHA and their bioavailabilities. Our results provide guidance for the application of fish oil for bone health.

Vascepa protects against high-fat diet-induced glucose intolerance, insulin resistance, and impaired β-cell function

SummaryOmega-3 fatty acid prescription drugs, Vascepa (≥96% eicosapentaenoic acid [EPA] ethyl ester) and Lovaza (46.5% EPA and 37.5% docosahexaenoic acid ethyl ester) are known therapeutic regimens to treat hypertriglyceridemia. However, their impact on glucose homeostasis, progression to type 2 diabetes, and pancreatic beta cell function are not well understood. In the present study, mice were treated with Vascepa or Lovaza for one week prior to six weeks of high-fat diet feeding. Vascepa but not Lovaza led to reduced insulin resistance, reduced fasting insulin and glucose, and improved glucose intolerance. Vascepa improved beta cell function, reduced liver triglycerides with enhanced expression of hepatic fatty acid oxidation genes, and altered microbiota composition. Vascepa has protective effects on diet-induced insulin resistance and glucose intolerance in mice.