Showing papers in "Lipids in 2011"

Dietary monounsaturated fatty acids are protective against metabolic syndrome and cardiovascular disease risk factors.

Abstract: Over 50 years of research has sought to define the role dietary fat plays in cardiovascular disease (CVD) risk. Although optimal dietary fat quantity has been keenly pursued over past decades, attention has recently centered on the value of dietary fat quality. The purpose of the present review is to provide a critical assessment of the current body of evidence surrounding efficacy of dietary monounsaturated fatty acids (MUFA) for reduction of traditional risk factors defining metabolic syndrome (MetS) and CVD. Due to existing and emerging research on health attributes of MUFA rich diets, and to the low prevalence of chronic disease in populations consuming MUFA rich Mediterranean diets, national dietary guidelines are increasingly recommending dietary MUFA, primarily at the expense of saturated fatty acids (SFA). Consumption of dietary MUFA promotes healthy blood lipid profiles, mediates blood pressure, improves insulin sensitivity and regulates glucose levels. Moreover, provocative newer data suggest a role for preferential oxidation and metabolism of dietary MUFA, influencing body composition and ameliorating the risk of obesity. Mounting epidemiological and human clinical trial data continue to demonstrate the cardioprotective activity of the MUFA content of dietary fat. As the debate on the optimal fatty acid composition of the diet continues, the benefit of increasing MUFA intakes, particularly as a substitute for dietary SFA, deserves considerable attention.

Metabolic Effects of Krill Oil are Essentially Similar to Those of Fish Oil but at Lower Dose of EPA and DHA, in Healthy Volunteers

Abstract: The purpose of the present study is to investigate the effects of krill oil and fish oil on serum lipids and markers of oxidative stress and inflammation and to evaluate if different molecular forms, triacylglycerol and phospholipids, of omega-3 polyunsaturated fatty acids (PUFAs) influence the plasma level of EPA and DHA differently. One hundred thirteen subjects with normal or slightly elevated total blood cholesterol and/or triglyceride levels were randomized into three groups and given either six capsules of krill oil (N = 36; 3.0 g/day, EPA + DHA = 543 mg) or three capsules of fish oil (N = 40; 1.8 g/day, EPA + DHA = 864 mg) daily for 7 weeks. A third group did not receive any supplementation and served as controls (N = 37). A significant increase in plasma EPA, DHA, and DPA was observed in the subjects supplemented with n-3 PUFAs as compared with the controls, but there were no significant differences in the changes in any of the n-3 PUFAs between the fish oil and the krill oil groups. No statistically significant differences in changes in any of the serum lipids or the markers of oxidative stress and inflammation between the study groups were observed. Krill oil and fish oil thus represent comparable dietary sources of n-3 PUFAs, even if the EPA + DHA dose in the krill oil was 62.8% of that in the fish oil.

Rapid Quantitative Analysis of Lipids Using a Colorimetric Method in a Microplate Format

Abstract: A colorimetric sulfo-phospho-vanillin (SPV) method was developed for high throughput analysis of total lipids. The developed method uses a reaction mixture that is maintained in a 96-well microplate throughout the entire assay. The new assay provides the following advantages over other methods of lipid measurement: (1) background absorbance can be easily corrected for each well, (2) there is less risk of handling and transferring sulfuric acid contained in reaction mixtures, (3) color develops more consistently providing more accurate measurement of absorbance, and (4) the assay can be used for quantitative measurement of lipids extracted from a wide variety of sources. Unlike other spectrophotometric approaches that use fluorescent dyes, the optimal spectra and reaction conditions for the developed assay do not vary with the sample source. The developed method was used to measure lipids in extracts from four strains of microalgae. No significant difference was found in lipid determination when lipid content was measured using the new method and compared to results obtained using a macro-gravimetric method.

The Health Promoting Properties of the Conjugated Isomers of α-Linolenic Acid

Abstract: The bioactive properties of the conjugated linoleic acid (CLA) isomers have long been recognised and are the subject of a number of excellent reviews. However, despite this prominence the CLA isomers are not the only group of naturally occurring dietary conjugated fatty acids which have shown potent bioactivity. In a large number of in vitro and in vivo studies, conjugated α-linolenic acid (CLNA) isomers have displayed potent anti-inflammatory, immunomodulatory, anti-obese and anti-carcinogenic activity, along with the ability to improve biomarkers of cardio-vascular health. CLNA isomers are naturally present in high concentrations in a large variety of seed oils but can also be produced in vitro by strains of lactobacilli and bifidobactena through the activity of the enzyme linoleic acid isomerase on α-linolenic acid. In this review, we will address the possible therapeutic roles that CLNA may play in a number of conditions afflicting Western society and the mechanisms through which this activity is mediated.

Simvastatin therapy reduces prooxidant-antioxidant balance: results of a placebo-controlled cross-over trial

Abstract: Oxidative stress is thought to play an important role in atherogenesis. The statin group of cholesterol-lowering drugs have been shown to reduce cardiovascular events and possess antioxidant properties. We aimed to assess the effects of simvastatin on a novel measure of prooxidant-antioxidant balance (PAB) in dyslipidemic patients. The PAB assay can measure the prooxidant burden and the antioxidant capacity simultaneously in one assay, thereby giving a redox index. We treated 102 dyslipidemic individuals with simvastatin, or a placebo in a double-blind, cross-over, placebo-controlled trial. PAB values were measured before and after each treatment period. Seventy-seven subjects completed the study. We found that statin therapy was associated with a significant reduction in PAB values (P < 0.001). This effect appeared to be independent of the cholesterol-lowering effects of statins. We conclude that serum PAB values are decreased by simvastatin therapy. Regarding previous reports on the elevation of PAB in conditions associated with oxidative stress, the PAB assay, along with other markers of oxidative stress, may be applied to estimate the extent of oxidative stress in patients, assessment of the antioxidative efficacy of medication such as statins and perhaps also for the identification of those individuals who need antioxidant therapy.

Elucidation of Phosphatidylcholine Composition in Krill Oil Extracted from Euphausia superba

Abstract: High performance liquid chromatography-electrospray tandem mass spectrometry was used to elucidate the phospholipids in krill oil extracted from Euphausia superba, an emerging source for human nutritional supplements. The study was carried out in order to map the species of the choline-containing phospholipid classes: phosphatidylcholine and lyso-phosphatidylcholine. In addition, the prevalent phosphatidylcholine class was quantified and the results compared with prior analysis. The qualification was performed with separation on a reverse phase chromatography column, while the quantification was obtained with class separation on a normal phase chromatography column. An Orbitrap system was used for the detection, and pulsed-Q dissociation fragmentation was utilized for the identification of the species. An asymmetrical exclusion list was applied for detection of phospholipid species of lower concentration, significantly improving the number of species observed. A total of 69 choline-containing phospholipids were detected, whereof 60 phosphatidylcholine substances, among others seven with probable omega-3 fatty acids in both sn-1 and sn-2. The phosphatidylcholine concentration was estimated to be 34 ± 5 g/100 g oil (n = 5). These results confirm the complexity of the phospholipid composition of krill oil, and the presence of long chained, heavily unsaturated fatty acids.

Oxidative Stability of Marine Phospholipids in the Liposomal Form and Their Applications

Abstract: Marine phospholipids (MPL) have attracted a great deal of attention recently as they are considered to have a better bioavailability, a better resistance towards oxidation and a higher content of eicosapentaenoic (EPA) and docosahexaenoic acids (DHA) than oily triglycerides (fish oil) from the same source. Due to their tight intermolecular packing conformation at the sn-2 position and their synergism with α-tocopherol present in MPL extracts, they can form stable liposomes which are attractive ingredients for food or feed applications. However, MPL are still susceptible to oxidation as they contain large amounts polyunsaturated fatty acids and application of MPL in food and aquaculture industries is therefore a great challenge for researchers. Hence, knowledge on the oxidative stability of MPL and the behavior of MPL in food and feed systems is an important issue. For this reason, this review was undertaken to provide the industry and academia with an overview of (1) the stability of MPL in different forms and their potential as liposomal material, and (2) the current applications and future prospects of MPL in both food and aquaculture industries with special emphasis on MPL in the liposomal form.

Isolation of a Novel Oil Globule Protein from the Green Alga Haematococcus pluvialis (Chlorophyceae)

Abstract: Cytoplasmic oil globules of Haematococcus pluvialis (Chlorophyceae) were isolated and analyzed for pigments, lipids and proteins. Astaxanthin appeared to be the only pigment deposited in the globules. Triacyglycerols were the main lipids (more than 90% of total fatty acids) in both the cell-free extract and in the oil globules. Lipid profile analysis of the oil globules showed that relative to the cell-free extract, they were enriched with extraplastidial lipids. A fatty acids profile revealed that the major fatty acids in the isolated globules were oleic acid (18:1) and linoleic acid (18:2). Protein extracts from the globules revealed seven enriched protein bands, all of which were possible globule-associated proteins. A major 33-kDa globule protein was partially sequenced by MS/MS analysis, and degenerate DNA primers were prepared and utilized to clone its encoding gene from cDNA extracted from cells grown in a nitrogen depleted medium under high light. The sequence of this 275-amino acid protein, termed the Haematococcus Oil Globule Protein (HOGP), revealed partial homology with a Chlamydomonas reinhardtii oil globule protein and with undefined proteins from other green algae. The HOGP transcript was barely detectable in vegetative cells, but its level increased by more than 100 fold within 12 h of exposure to nitrogen depletion/high light conditions, which induced oil accumulation. HOGP is the first oil-globule-associated protein to be identified in H. pluvialis, and it is a member of a novel gene family that may be unique to green microalgae.

LC-PUFA Biosynthesis in Rainbow Trout is Substrate Limited: Use of the Whole Body Fatty Acid Balance Method and Different 18:3n-3/18:2n-6 Ratios

Abstract: Five experimental diets with constant total C18 PUFA and varying 18:3n-3/18:2n-6 ratios were fed to rainbow trout over an entire production cycle. The whole-body fatty acid balance method demonstrated a clear trend of progressively reduced fatty acid bioconversion activity along the n-3 and n-6 pathways, up to the production of 20:5n-3 and 20:4n-6, respectively. This suggests that the pathway exhibits a “funnel like” progression of activity rather than the existence of a single rate limiting step. The production of 22:5n-3 and 22:6n-3 was more active than that of 20:5n-3. However, despite this trend in reduced apparent in vivo net enzyme activity, the efficiency of the various bioconversion steps (measured as % of bioconverted substrate) confirmed an opposing trend. A 3.2-fold higher Δ-6 desaturase affinity towards 18:3n-3 over 18:2n-6 and an 8-fold greater Δ-5 desaturase affinity towards 20:4n-3 over 20:3n-6 were recorded. The main results of the study were that (1) rainbow trout are quite efficient at bioconverting 18:3n-3 to 22:6n-3, and (2) the LC-PUFA biosynthetic pathway is substrate limited. Fillet n-3 LC-PUFA concentrations increased with the increasing dietary supply of 18:3n-3. Despite an almost identical dietary supply of n-3 LC-PUFA, originating from the fish meal fraction of the diets, the fillets of trout fed the diet richest in 18:3n-3 were 2-fold higher in n-3 LC-PUFA than fish fed low 18:3n-3 diets. Nevertheless, fillets of trout fed a fish oil control diet contained more than double the amount of n-3 LC-PUFA compared to fish fed the diets richest in 18:3n-3.

Low Levels of the Omega-3 Index are Associated with Sudden Cardiac Arrest and Remain Stable in Survivors in the Subacute Phase

Abstract: In previous studies, low blood levels of n-3 fatty acids (FA) have been associated with increased risk of cardiac death, and the omega-3 index (red blood cell (RBC) eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) expressed as weight percentage of total FA) has recently been proposed as a new risk factor for death from coronary artery disease, especially following sudden cardiac arrest (SCA). As blood samples often haven been harvested after the event, the aim of our study was to evaluate the stability of RBC fatty acids following SCA. The total FA profile, including the omega-3 index, was measured three times during the first 48 h in 25 survivors of out-of-hospital cardiac arrest (OHCA), in 15 patients with a myocardial infarction (MI) without SCA and in 5 healthy subjects. We could not demonstrate significant changes in the FA measurements in any of the groups, this also applied to the omega-6/omega-3 ratio and the arachidonic acid (AA)/EPA ratio. Furthermore, we compared the omega-3 index in 14 OHCA-patients suffering their first MI with that of 185 first-time MI-patients without SCA; mean values being 4.59% and 6.48%, respectively (p = 0.002). In a multivariate logistic regression analysis, a 1% increase of the omega-3 index was associated with a 58% (95% CI: 0.25–0.76%) reduction in risk of ventricular fibrillation (VF). In conclusion, the omega-3 index remained stable after an event of SCA and predicted the risk of VF.

Insulin Stimulates Lipogenesis and Attenuates Beta‐Oxidation in White Adipose Tissue of Fed Rainbow Trout

Abstract: As lipid deposition tissue in fish, the white adipose tissue (WAT) has important functions related to reproduction and the challenges of long-term fasting. In the study reported here, we infused fish fed a high-carbohydrate diet with two doses of insulin for 5 days in order to explore the effects of this hormone on lipogenesis and beta-oxidation-related enzymes. We demonstrated the presence of some of the main lipogenic enzymes at molecular, protein and activity levels (ATP-citrate lyase and fatty acid synthase). However, while ATP-citrate lyase was unexpectedly down-regulated, fatty acid synthase was up-regulated (at protein and activity levels) in an insulin dose-dependent manner. The main enzymes acting as NADPH donors for lipogenesis were also characterized at biochemical and molecular levels, although there was no evidence of their regulation by insulin. On the other hand, lipid oxidation potential was found in this tissue through the measurement of gene expression of enzymes involved in β-oxidation, highlighting two carnitine palmitoyltransferase isoforms, both down-regulated by insulin infusion. We found that insulin acts as an important regulator of trout WAT lipid metabolism, inducing the final stage of lipogenesis at molecular, protein and enzyme activity levels and suppressing β-oxidation at least at a molecular level. These results suggest that WAT in fish may have a role that is important not only as a lipid deposition tissue but also as a lipogenic organ (with possible involvement in glucose homeostasis) that could also be able to utilize the lipids stored as a local energy source.

Branched Chain Fatty Acid Content of United States Retail Cow’s Milk and Implications for Dietary Intake

Abstract: Branched chain fatty acids (BCFA) have recently been shown to be a major component of the normal human newborn gastrointestinal tract and have long been known to be a component of human milk. Ruminant food products are major sources of fat in the American diet, but there are no studies of milkfat BCFA content in retail milk. We report here the profile and concentrations of BCFA in a representative sampling of retail milk in the 48 contiguous United States (US), and their estimated intake in the American diet. Conventionally produced whole fluid milk samples were obtained from 56 processing plants across the contiguous 48 states. Retail milk samples contain exclusively iso- and anteiso-BCFA with 14–18 carbons. BCFA were 2.05 ± 0.14%, w/w of milkfat fatty acids (mean ± SD), and anteiso-BCFA comprised more than half this total. Based on these data and USDA food availability data, the average per capita BCFA intake of Americans is estimated to be about 220 mg/d from dairy; if current dietary recommendations were followed, BCFA intake would be about 400 mg/d. Adding intake from beef consumption, these estimates rise to approximately 400 and 575 mg/d, respectively. These results indicate that BCFA intake is a substantial fraction of daily fat intake, in amounts exceeding those of many bioactive fatty acids.

Mild Method for Preparation of 4,4-Dimethyloxazoline Derivatives of Polyunsaturated Fatty Acids for GC-MS

Abstract: A mild and convenient method has been developed for preparing 4,4-dimethyloxazoline (DMOX) derivatives of fatty acids for GC-MS analysis. First, fatty acid methyl esters are converted to corresponding amides by incubation overnight at room temperature with 2-amino-2-methyl-1-propanol and a catalytic amount of sodium methoxide. The resulting 2-(methylpropanol) amides were isolated by partition between hexane-diethyl ether and water, and then converted to 4,4-dimethyloxazoline derivatives by treatment with trifluoroacetic anhydride under mild conditions (50 °C for 45 min). Structures of 2-methylpropanol amide and a DMOX derivative of oleic acid were confirmed by GC-MS. This method was applied to different FAME prepared from animal, plant or microbial lipids. The suggested method is most suitable for structure analysis of polyunsaturated fatty acids (PUFA) and for acids with double bonds in close to terminal positions. Application of the method is illustrated with spectra of the DMOX derivatives of 16:1(n-13), 24:5(n-6) and 24:6(n-3) acids.

Dietary n-3 fatty acid deficiency in mice enhances anxiety induced by chronic mild stress.

Abstract: Docosahexaenoic acid (DHA), is the major polyunsaturated fatty acid in the brain and is important for both the structure and the function of the nervous system. Mice were fed either an n-3 fatty acid deficient (n-3 Def) or adequate (n-3 Adq) diet for two generations. The mice were housed under two conditions, as a group or in isolation and the major point of the study was to determine whether n-3 fatty acid deficiency would enhance isolation-induced anxiety. Isolation stress was assessed using the novelty suppressed feeding paradigm (NSF) after a 3-week period and the test lasted a maximal duration of 10 min. The number of successful mice consuming food pellets within 5 min in the n-3 Def diet group was low in both housing conditions (group housing, 33% and isolated, 30%), but was 92% in the group housed and 50% in the isolated group when fed the n-3 Adq diet. In the subsequent 5 min period, the isolated housing group consuming the n-3 Adq diet increased up to 79% and the group housed animals fed the n-3 Def diet increased to 67%. However, those that consumed the n-3 deficient diet combined with isolation stress exhibited no increase. These results suggested that the n-3 deficient mice had increased anxiety that was enhanced by the chronic mild stress of social isolation.

Fish Oil Supplementation During Lactation: Effects on Cognition and Behavior at 7 Years of Age

Abstract: Early accumulation of n-3 long-chain PUFA (LCPUFA) in the brain may contribute to differences in later cognitive abilities. In this study, our objective was to examine whether fish oil (FO) supplementation during lactation affects processing speed, working memory, inhibitory control, and socioemotional development at 7 years. Danish mothers (n = 122) were randomized to FO [1.5 g/d n-3 LCPUFA] or olive oil (OO) supplementation during the first 4 months of lactation. The trial also included a high-fish intake (HFI) reference group (n = 53). Ninety-eight children were followed-up with an assessment of processing speed, an age-appropriate Stroop task, and the Strength and Difficulties Questionnaire at 7 year. A group effect of the intervention (FO vs. OO) was found in prosocial behavior scores; this negative effect was carried by the boys. Exploratory analyses including all participants revealed the speed of processing scores were predicted by maternal n-3 LCPUFA intake during the intervention period (negative relation) and maternal education (positive relation). Stroop scores indicative of working memory and inhibitory control were predicted by infant erythrocyte DHA status at 4 months of age (negative relation). Early fish oil supplementation may have a negative effect on later cognitive abilities. Speed of processing and inhibitory control/working memory are differentially affected, with speed of processing showing effects of fish oil intake as a whole, whereas inhibitory control/working memory was related more specifically to DHA status.

Is the fatty acid composition of freshwater zoobenthic invertebrates controlled by phylogenetic or trophic factors

Abstract: We studied the fatty acid (FA) content and composition of ten zoobenthic species of several taxonomic groups from different freshwater bodies. Special attention was paid to essential polyunsaturated fatty acids, eicosapentaenoic acid (EPA, 20:5n-3), docosahexaenoic acid (DHA, 22:6n-3), and arachidonic acid (ARA, 20:4n-6); and the n-3/n-6 and DHA/ARA ratios, which are important for consumers of higher trophic levels, i.e., fish. The content and ratios of these FA varied significantly in the studied zoobenthic species, consequently, the invertebrates were of different nutritional quality for fish. Eulimnogammarus viridis (Crustacea) and Dendrocoelopsis sp. (Turbellaria) had the highest nutrition value for fish concerning the content of EPA and DHA and n-3/n-6 and DHA/ARA ratios. Using canonical correspondence analysis we compared the FA profiles of species of the studied taxa taking into account their feeding strategies and habitats. We gained evidence that feeding strategy is of importance to determine fatty acid profiles of zoobenthic species. However, the phylogenetic position of the zoobenthic species is also responsible and may result in a similar fatty acid composition even if species or populations inhabit different water bodies or have different feeding strategies.

LipidomeDB Data Calculation Environment: Online Processing of Direct-Infusion Mass Spectral Data for Lipid Profiles

Abstract: LipidomeDB Data Calculation Environment (DCE) is a web application to quantify complex lipids by processing data acquired after direct infusion of a lipid-containing biological extract, to which a cocktail of internal standards has been added, into an electrospray source of a triple quadrupole mass spectrometer. LipidomeDB DCE is located on the public Internet at http://lipidome.bcf.ku.edu:9000/Lipidomics. LipidomeDB DCE supports targeted analyses; analyte information can be entered, or pre-formulated lists of typical plant or animal polar lipid analytes can be selected. LipidomeDB DCE performs isotopic deconvolution and quantification in comparison to internal standard spectral peaks. Multiple precursor or neutral loss spectra from up to 35 samples may be processed simultaneously with data input as Excel files and output as tables viewable on the web and exportable in Excel. The pre-formulated compound lists and web access, used with direct-infusion mass spectrometry, provide a simple approach to lipidomic analysis, particularly for new users.

Dietary n-3 Fatty Acids Significantly Suppress Lipogenesis in Bovine Muscle and Adipose Tissue: A Functional Genomics Approach

Abstract: Changes in fatty acid composition of longissimus muscle and subcutaneous adipose tissue of German Holstein bulls induced by a grass-silage/n-3 fatty acid based intervention diet versus a maize-silage/n-6 fatty acid based control diet were analyzed and related to shifts in lipogenic gene expression, protein expression, and enzyme activity patterns. Significantly higher amounts of n-3 fatty acids and by mean factors of 2.2–2.5 decreased n-6/n-3 fatty acid ratios in both tissues were obtained upon n-3 fatty acid intervention. In longissimus muscle, these changes of fatty acid profiles were associated with reduced SREBP1c (p = 0.02), ACC (p = 0.00), FAS (p = 0.10) and SCD (p = 0.03) gene expression, Δ6D (p = 0.03) and SCD (p = 0.03) protein expression as well as SCD enzyme activity (p = 0.03). In subcutaneous adipose tissue, significantly reduced ACC (p = 0.00) and FAS (p = 0.01) gene expression, SCD protein expression (p = 0.02) and SCD enzyme activity (p = 0.03) were detected upon n-3 fatty acid intervention, although lower degrees of correlation between gene and corresponding gene products were obtained in relation to longissimus muscle. The study elucidates tissue-specific functional genomic responses to dietary fatty acid manipulation in regard to fatty acid profile tailoring of animal tissues.

The Alpha Linolenic Acid Content of Flaxseed is Associated with an Induction of Adipose Leptin Expression

Abstract: Dietary flaxseed has cardioprotective effects that may be achieved through its rich content of the omega-3 fatty acid, alpha linolenic acid (ALA). Because ALA can be stored in adipose tissue, it is possible that some of its beneficial actions may be due to effects it has on the adipose tissue. We investigated the effects of dietary flaxseed both with and without an atherogenic cholesterol-enriched diet to determine the effects of dietary flaxseed on the expression of the adipose cytokines leptin and adiponectin. Rabbits were fed one of four diets: a regular (RG) diet, or a regular diet with added 0.5% cholesterol (CH), or 10% ground flaxseed (FX), or both (CF) for 8 weeks. Levels of leptin and adiponectin expression were assessed by RT-PCR in visceral adipose tissue. Consumption of flaxseed significantly increased plasma and adipose levels of ALA. Leptin protein and mRNA expression were lower in CH animals and were elevated in CF animals. Changes in leptin expression were strongly and positively correlated with adipose ALA levels and inversely correlated with levels of en face atherosclerosis. Adiponectin expression was not significantly affected by any of the dietary interventions. Our data demonstrate that the type of fat in the diet as well as its caloric content can specifically influence leptin expression. The findings support the hypothesis that the beneficial cardiovascular effects associated with flaxseed consumption may be related to a change in leptin expression.

2-Polyunsaturated Acyl Lysophosphatidylethanolamine Attenuates Inflammatory Response in Zymosan A-Induced Peritonitis in Mice

Abstract: In the present study, the anti-inflammatory action of lysophosphatidylethanolamine (lysoPtdEtn), orally administered, in zymosan A-induced peritonitis was examined. Oral administration of 2-DHA-lysoPtdEtn (ED50, ~111 μg/kg) or 2-ARA-lysoPtdEtn (ED50, 221 μg/kg) was found to inhibit the plasma leakage in mice treated with zymosan A. In support of this, 2-polyunsaturated acyl-lysoPtdEtn diminished the formation of LTC4, a lipid mediator responsible for vascular permeability. Next, 2-DHA-lysoPtdEtn (ED50, 110 μg/kg) or 2-ARA-lysoPtdEtn (ED50, 123 μg/kg) effectively inhibited the leukocyte extravasation into the peritoneum. Consistent with this, each polyunsaturated-lysoPtdEtn diminished the formation of LTB4 and 12-HETE, potent chemotactic factors. Additionally, the level of pro-inflammatory mediator (IL-1 β, IL-6, TNF-α or NO) was lowered remarkably in contrast to the augmentation of anti-inflammatory interleukin IL-10. Furthermore, 2-(15-HETE)-lysoPtdEtn and 2-(17-HDHE)-lysoPtdEtn, 15-lipoxygenation product of 2-ARA-lysoPtdEtn and 2-DHA-lysoPtdEtn, respectively, were more potent than corresponding lysoPtdEtn, suggesting the action of 2-acyl-lysoPtdEtn might be expressed through 15-lipoxygenation. In support of this, the formation of 15-HETE and LXA4 was upgraded in accordance with an increasing dose of 2-ARA-lysoPtdEtn. Separately, anti-inflammatory actions, 2-polyunsaturated acyl-lysoPtdEtns also drastically diminished leukocyte infiltration in a later phase of zymosan A-induced peritonitis, indicating that these lipids also possess pro-resolving activity. Taken together, it is suggested that polyunsaturated lysoPtdEtns and their lipoxygenation derivatives, could be classified as potent anti-inflammatory lipids.

Identification and Ruminal Outflow of Long-Chain Fatty Acid Biohydrogenation Intermediates in Cows Fed Diets Containing Fish Oil

Abstract: The abundance of 20- to 24-carbon fatty acids in omasal digesta of cows fed grass silage-based diets supplemented with 0 (Control) and 250 g/day of fish oil (FO) was examined to investigate the fate of long-chain unsaturated fatty acids in the rumen. Complimentary argentation thin-layer chromatography and gas-chromatography mass-spectrometry analysis of fatty acid methyl esters and corresponding 4,4-dimethyloxazoline derivatives prepared from fish oil and omasal digesta enabled the structure of novel 20- to 22-carbon fatty acids to be elucidated. Compared with the Control, the FO treatment resulted in the formation and accumulation of 27 novel 20- and 22-carbon biohydrogenation intermediates containing at least one trans double bond and the appearance of cis-14 20:1, 20:2n-3, 21:4n-3 and 22:3n-6 not contained in fish oil. No conjugated ≥20-carbon fatty acids were detected in Control or FO digesta. In conclusion, fish oil in the diet results in the formation of numerous long-chain biohydrogenation intermediates in the rumen of lactating cows. Comparison of the intake and flow of 20-, 21- and 22-carbon fatty acids at the omasum in cows fed the Control and FO treatments suggests that the first committed steps of 20:5n-3, 21:5n-3 and 22:6n-3 hydrogenation in the rumen involve the reduction and/or isomerisation of double bonds closest to the carboxyl group.

Palm olein and olive oil cause a higher increase in postprandial lipemia compared with lard but had no effect on plasma glucose, insulin and adipocytokines.

Abstract: Postprandial lipemia impairs insulin sensitivity and triggers the pro-inflammatory state which may lead to the progression of cardiovascular diseases. A randomized, crossover single-blind study (n = 10 healthy men) was designed to compare the effects of a high-fat load (50 g fat), rich in palmitic acid from both plant (palm olein) or animal source (lard) versus an oleic acid-rich fat (virgin olive oil) on lipemia, plasma glucose, insulin and adipocytokines. Serum triacylglycerol (TAG) concentrations were significantly lower after the lard meal than after the olive oil and palm olein meals (meal effect P = 0.003; time effect P < 0.001). The greater reduction in the plasma non-esterified free fatty acids levels in the lard group compared to the olive oil meal was mirrored by the changes observed for serum TAG levels (P < 0.05). The magnitude of response for plasma glucose, insulin and adipocytokines [interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and leptin] were not altered by the type of dietary fats. A significant difference in plasma IL-1β was found over time following the three high fat loads (time effect P = 0.036). The physical characteristics and changes in TAG structure of lard may contribute to the smaller increase in postprandial lipemia compared with palm olein. A high fat load but not the type of fats influences concentrations of plasma IL-1β over time but had no effect on other pro-inflammatory markers tested in the postprandial state.

trans-trans Conjugated linoleic acid enriched soybean oil reduces fatty liver and lowers serum cholesterol in obese zucker rats.

Abstract: Conjugated linoleic acid (CLA) is a collection of octadecadienoic fatty acids that have been shown to possess numerous health benefits. The CLA used in our study was produced by the photoisomerization of soybean oil and consists of about 20% CLA; this CLA consists of 75% trans–trans (a mixture of t8,t10; t9,t11; t10,t12) isomers. This method could be readily used to increase the CLA content of all soybean oil used as a food ingredient. The objective of this study was to determine the effects of trans–trans CLA-rich soy oil, fed as a dietary supplement, on body composition, dyslipidemia, hepatic steatosis, and markers of glucose control and liver function of obese fa/fa Zucker rats. The trans–trans CLA-rich soy oil lowered the serum cholesterol and low density lipoprotein–cholesterol levels by 41 and 50%, respectively, when compared to obese controls. Trans–trans CLA-rich soy oil supplementation also lowered the liver lipid content significantly (P < 0.05) with a concomitant decrease in the liver weight in the obese rats. In addition, glycated hemoglobin values were improved in the group receiving CLA-enriched soybean oil in comparison to the obese control. PPAR-γ expression in white adipose tissue was unchanged. In conclusion, trans–trans CLA-rich soy oil was effective in lowering total liver lipids and serum cholesterol.

Oral Docosapentaenoic Acid (22:5n-3) Is Differentially Incorporated into Phospholipid Pools and Differentially Metabolized to Eicosapentaenoic Acid in Tissues from Young Rats

Abstract: The present study assessed the effect of oral supplementation with docosapentaenoic acid (DPA, 22:5n-3) on the levels of serum and tissue lipid classes and their fatty acid compositions including individual phospholipid types in rat liver, heart, and kidney. Sprague–Dawley rats received daily oral gavage over 10 days as corn oil without (controls) or with purified DPA in free fatty acid form (21.2 mg/day). The DPA group exhibited significantly lower serum lipid concentrations. The concentrations in μmol/100 g serum or μmol/g tissue of DPA in the total lipid (TL) were higher by 2.3-, 2.4-, 10.9-, and 5.1-fold in the DPA group of serum, liver, heart, and kidney, respectively, with the phospholipids (PL) being the major DPA reservoir (45.2–52.1% of the DPA in the TL). No significant differences in DHA (22:6n-3) amounts in TL appeared. The highest relative mol% values as DPA were in heart tissue (means of 11.1% in PL and 16.2% in phosphatidylinositol) and lowest in kidney. The EPA (20:5n-3) concentrations were markedly higher in the DPA group and most pronounced in the kidney (5.1 times higher in the TL as compared to controls) relative to liver and heart yielding an estimated apparent % conversion of DPA to EPA of 67% and EPA:DPA ratios reaching 5.74 in kidney phosphatidylethanolamine. The serum lipid-lowering potential of dietary DPA and its impact in the kidney with the derived EPA warrants investigation.

Glycosidic bond cleavage is not required for phytosteryl glycoside-induced reduction of cholesterol absorption in mice.

Abstract: Phytosteryl glycosides occur in natural foods but little is known about their metabolism and bioactivity. Purified acylated steryl glycosides (ASG) were compared with phytosteryl esters (PSE) in mice. Animals on a phytosterol-free diet received ASG or PSE by gavage in purified soybean oil along with tracers cholesterol-d7 and sitostanol-d4. In a three-day fecal recovery study, ASG reduced cholesterol absorption efficiency by 45 ± 6% compared with 40 ± 6% observed with PSE. Four hours after gavage, plasma and liver cholesterol-d7 levels were reduced 86% or more when ASG was present. Liver total phytosterols were unchanged after ASG administration but were significantly increased after PSE. After ASG treatment both ASG and deacylated steryl glycosides (SG) were found in the gut mucosa and lumen. ASG was quantitatively recovered from stool samples as SG. These results demonstrate that ASG reduces cholesterol absorption in mice as efficiently as PSE while having little systemic absorption itself. Cleavage of the glycosidic linkage is not required for biological activity of ASG. Phytosteryl glycosides should be included in measurements of bioactive phytosterols.

Modeling the Primary Oxidation in Commercial Fish Oil Preparations

Abstract: The quality of commercial fish oil products can be difficult to maintain because of the rapid lipid oxidation attributable to the high number of polyunsaturated fatty acids (PUFA), specifically eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). While it is known that oxidation in fish oil is generally the result of a direct interaction with oxygen and fatty acid radicals, there are very few studies that investigate the oxidation kinetics of fish oil supplements. This study uses hydroperoxides, a primary oxidation product, to model the oxidation kinetics of two commercially available fish oil supplements with different EPA and DHA contents. Pseudo first order kinetics were assumed, and rate constants were determined for temperatures between 4 and 60 °C. This data was fit to the Arrhenius model, and activation energies (E(a)) were determined for each sample. Both E(a) agreed with values found in the literature, with the lower PUFA sample having a lower E(a). The oil with a lower PUFA content fit the first-order kinetics model at temperatures ≥20 °C and ≤40 °C, while the higher PUFA oil demonstrated first-order kinetics at temperatures ≥4 °C and ≤40 °C. When the temperature was raised to 60 °C, the model no longer applied. This indicates that accelerated testing of fish oil should be conducted at temperatures ≤40 °C.

Dietary Glucosylceramide Enhances Cornified Envelope Formation via Transglutaminase Expression and Involucrin Production

Abstract: In this study, we investigated whether dietary glucosylceramide (GlcCer) and its metabolite sphingoid bases, sphingosine (SS), phytosphingosine (PS), sphingadienine (SD) and 4-hydroxysphingenine (4HS), influence cornified envelope (CE) formation. CE is formed during terminal differentiation of the epidermis through crosslinking of specific precursor proteins by transglutaminases (TGases), and is essential for the skin's barrier function. Oral administration of GlcCer (0.25 mg/day) for 14 consecutive days dramatically reduced transepidermal water loss, an indicator of the skin barrier condition, in hairless mice with barrier perturbation induced by single-dose ultraviolet B (UVB) irradiation. The GlcCer treatment also increased the level of TGase-1 mRNA in UVB-irradiated murine epidermis approximately 1.6-fold compared with the control. Further, all four sphingoid bases at 1 μM concentration enhanced CE formation of cultured normal human keratinocyte cells. Among them, SS, PS and SD, but not 4HS, stimulated production of involucrin, one of the CE major precursor proteins. SD increased the expression of TGase-1 mRNA, while SS increased the expression of TGase-3 mRNA. These results indicate that the skin barrier improvement induced by oral GlcCer treatment might be at least partly due to a reinforcement of CE formation in the epidermis mediated by sphingoid bases metabolically derived from GlcCer.

Dietary Saury Oil Reduces Hyperglycemia and Hyperlipidemia in Diabetic KKAy Mice and in Diet-Induced Obese C57BL/6J Mice by Altering Gene Expression

Abstract: We investigated the effect of saury oil on the alleviation of metabolic syndrome in mice. Saury oil contains 18% (w/w/) n-3 polyunsaturated fatty acids (n-3 PUFA) and 35% (w/w) monounsaturated fatty acids (MUFA). Diabetic KKAy mice were fed a 10% soybean oil diet (control) or a 10% saury oil diet for 4 weeks, and diet-induced obese C57BL/6J mice were fed a high-fat diet containing 32% lard (control) or 22% lard plus 10% saury oil for 6 weeks. After the intervention periods, the levels of glucose, insulin and lipids in plasma had decreased significantly for the saury oil diet group, and insulin sensitivity had improved. These favorable changes may be attributed to the increased adiponectin and decreased TNFα and resistin levels in plasma. The saury oil diet also resulted in downregulated expression of the lipogenic genes (SREBP-1, SCD-1, FAS, and ACC) as well as upregulation of the fatty acid oxidative gene, CPT-1, and the energy expenditure-related genes (PGC1α and PGC1β) in white adipose tissue for the diet-induced obese C57BL/6J mice. An increase in n-3 PUFA levels and the concomitant decrease in the n-6/n-3 PUFA level ratio in serum, white adipose tissue, and liver with a saury oil diet are likely to be involved in the beneficial changes to the metabolic indicators. MUFA may also play a positive role in remodeling lipid composition. Based on these mice models, our results suggest a potential use for saury oil for improving metabolic abnormalities.

Oral Glucosylceramide Reduces 2,4-Dinitrofluorobenzene Induced Inflammatory Response in Mice by Reducing TNF-Alpha Levels and Leukocyte Infiltration

Abstract: Sphingolipids are constituents of cellular membranes and play important roles as second messengers mediating cell functions. As significant components in foods, sphingolipids have been proven to be critical for human health. Moreover, diverse metabolic intermediates of sphingolipids are known to play key roles both in proinflammatory and in anti-inflammatory effects. However, the effect of dietary sphingolipids on inflammation is a complicated field that needs to be further assessed. Our study evaluated the effects of orally administered maize glucosylceramide (GluCer), one of the most conventional dietary sphingolipids, on inflammation using the 2,4-dinitro-1-fluorobenzene-treated BALB/c murine model. Oral administration of GluCer inhibited ear swelling and leukocyte infiltration to the inflammatory site, suggesting that dietary GluCer has anti-inflammatory properties. ELISA analyses revealed that oral administration of GluCer for 6 days had not modified the Th1/Th2 balance, but significantly down-regulated the activation of TNF-α at the inflammatory site. Based on these results, the down-regulation of TNF-α by dietary GluCer may suppress vascular permeability and reduce the migration of inflammatory cells. Our findings increase understanding of the actions of dietary sphingolipids on the balance of the immune response.

Ezetimibe treatment lowers indicators of oxidative stress in hypercholesterolemic subjects with high oxidative stress.

Abstract: Ezetimibe effectively reduces low-density lipoprotein cholesterol (LDL-C). In this study, we tested the hypothesis that ezetimibe monotherapy may also decrease markers of oxidative stress in subjects with hypercholesterolemia. Subjects with hypercholesterolemia and no evidence of cardiovascular disease were randomly allocated to open-label ezetimibe monotherapy 10 mg/day (EZT group) or therapeutic lifestyle changes (TLC group). At baseline and 12 weeks post-treatment serum lipoprotein and apolipoprotein levels as well as oxidative stress parameters, including oxidized LDL (ox-LDL), 8-isoprostanes (8-epiPGF2a) and reactive oxygen metabolites (d-ROMs) levels, were blindly determined. A total of 60 patients were included; 30 in each group. Despite a significant decrease in ox-LDL levels (by 20.8%, p < 0.001 vs. baseline; p < 0.001 vs. TLC group) in the EZT group no change in the ratio ox-LDL to LDL-C was noticed following ezetimibe treatment. No significant change in 8-epiPGF2a and d-ROMs levels was observed in the EZT group. Of note, a significant decrease in 8-epiPGF2a and d-ROMs levels (by 20.4% and 18.2%, respectively, p < 0.01 vs. baseline for both), was noted among patients in the EZT group who exhibited ‘high oxidative stress’ at baseline. No change in any of oxidative stress parameters was noted in the TLC group. Ezetimibe may decrease markers of oxidative stress in hypercholesterolemic subjects. This benefit may be more profound among patients who exhibit ‘high oxidative stress’ at baseline.