Showing papers in "Lipids in 2014"

Consumption of Synbiotic Bread Decreases Triacylglycerol and VLDL Levels While Increasing HDL Levels in Serum from Patients with Type-2 Diabetes

Abstract: To our knowledge, no reports are available indicating the favorable effects of synbiotic bread consumption on blood lipid profiles among patients with type 2 diabetes mellitus (T2DM). This study was conducted to evaluate the effects of the daily consumption of synbiotic bread on blood lipid profiles of patients with T2DM. This randomized double-blinded controlled clinical trial was performed with 78 diabetic patients, aged 35-70 years. After a 2-week run-in period, subjects were randomly assigned to consume either synbiotic (n = 26), probiotic (n = 26) or control bread (n = 26) for 8 weeks. The synbiotic bread contained viable and heat-resistant probiotic Lactobacillus sporogenes (1 × 10(8) CFU) and 0.07 g inulin (HPX) as prebiotic per 1 g. The probiotic bread contained L. sporogenes (1 × 10(8) CFU) per 1 g. Patients were asked to consume the synbiotic, probiotic and control breads three times a day in a 40 g package for a total of 120 g/day. Biochemical measurements including blood lipid profiles were conducted before and after 8 weeks of intervention. Consumption of the synbiotic bread, compared to the probiotic and control breads, led to a significant decrease in serum TAG (P = 0.005), VLDL-C (P = 0.005), TC/HDL-C (P = 0.002) and a significant increase in serum HDL-C levels (P = 0.01). No significant effect of synbiotic bread consumption on FPG, TC, LDL-C and non-HDL-C levels was seen compared to the probiotic and control breads (P > 0.05). Trial registry code: http://www.irct.ir IRCT201311215623N13.

Changes in Tissue Lipid and Fatty Acid Composition of Farmed Rainbow Trout in Response to Dietary Camelina Oil as a Replacement of Fish Oil

Abstract: Camelina oil (CO) replaced 50 and 100 % of fish oil (FO) in diets for farmed rainbow trout (initial weight 44 ± 3 g fish−1). The oilseed is particularly unique due to its high lipid content (40 %) and high amount of 18:3n-3 (α-linolenic acid, ALA) (30 %). Replacing 100 % of fish oil with camelina oil did not negatively affect growth of rainbow trout after a 12-week feeding trial (FO = 168 ± 32 g fish−1; CO = 184 ± 35 g fish−1). Lipid and fatty acid profiles of muscle, viscera and skin were significantly affected by the addition of CO after 12 weeks of feeding. However, final 22:6n-3 [docosahexaenoic acid (DHA)] and 20:5n-3 [eicosapentaenoic acid (EPA)] amounts (563 mg) in a 75 g fillet (1 serving) were enough to satisfy daily DHA and EPA requirements (250 mg) set by the World Health Organization. Other health benefits include lower SFA and higher MUFA in filets fed CO versus FO. Compound-specific stable isotope analysis (CSIA) confirmed that the δ13C isotopic signature of DHA in CO fed trout shifted significantly compared to DHA in FO fed trout. The shift in DHA δ13C indicates mixing of a terrestrial isotopic signature compared to the isotopic signature of DHA in fish oil-fed tissue. These results suggest that ~27 % of DHA was synthesized from the terrestrial and isotopically lighter ALA in the CO diet rather than incorporation of DHA from fish meal in the CO diet. This was the first study to use CSIA in a feeding experiment to demonstrate synthesis of DHA in fish.

Dietary Linoleic Acid Elevates the Endocannabinoids 2-AG and Anandamide and Promotes Weight Gain in Mice Fed a Low Fat Diet

Abstract: Dietary intake of linoleic acid (LNA, 18:2n-6) has increased dramatically during the 20th century and is associated with greater prevalence of obesity. The endocannabinoid system is involved in regulation of energy balance and a sustained hyperactivity of the endocannabinoid system may contribute to obesity. Arachidonic acid (ARA, 20:4n-6) is the precursor for 2-AG and anandamide (AEA), and we sought to determine if low fat diets (LFD) could be made obesogenic by increasing the endocannabinoid precursor pool of ARA, causing excessive endocannabinoid signaling leading to weight gain and a metabolic profile associated with obesity. Mice (C57BL/6j, 6 weeks of age) were fed 1 en% LNA and 8 en% LNA in low fat (12.5 en%) and medium fat diets (MFD, 35 en%) for 16 weeks. We found that increasing dietary LNA from 1 to 8 en% in LFD and MFD significantly increased ARA in phospholipids (ARA–PL), elevated 2-AG and AEA in liver, elevated plasma leptin, and resulted in larger adipocytes and more macrophage infiltration in adipose tissue. In LFD, dietary LNA of 8 en% increased feed efficiency and caused greater weight gain than in an isocaloric reduction to 1 en% LNA. Increasing dietary LNA from 1 to 8 en% elevates liver endocannabinoid levels and increases the risk of developing obesity. Thus a high dietary content of LNA (8 en%) increases the adipogenic properties of a low fat diet.

The Synergism of Biochemical Components Controlling Lipid Oxidation in Lamb Muscle

Abstract: Lipid oxidation of M. longissimus lumborum in fresh or vacuum packaged (aged) lamb meat stored at 3 °C for 0 or 4 weeks, respectively and displayed under refrigerated conditions for a further 4 days was assessed by measuring the concentration of malondialdehyde (MDA) in meat using the thiobarbituric acid reactive substances procedure. The effects of vitamin E, heme iron and polyunsaturated fatty acids (n-6 and n-3) on lipid oxidation were examined. Results showed a strong positive relationship between heme iron, n-6 and n-3 fatty acids and lipid oxidation when vitamin E was below 2.95 mg/kg muscle. When lipid oxidation was related to vitamin E concentration and the other three variables, respectively, any increase in heme iron or n-6 or n-3 fatty acids concentration did not influence lipid oxidation. Management of diet to elevate muscle vitamin E concentration above 3.45 mg/kg muscle is beneficial to maintain the level of lipid oxidation below 2.4 mg MDA/kg muscle in meat stored for up to 4 weeks. This demonstrates that vitamin E concentration in muscle has a greater influence on controlling lipid oxidation in muscle tissues than do heme iron or polyunsaturated fatty acids.

Protectin DX, a Double Lipoxygenase Product of DHA, Inhibits Both ROS Production in Human Neutrophils and Cyclooxygenase Activities

Abstract: Neutrophils play a major role in inflammation by releasing large amounts of reactive oxygen species (ROS) produced by NADPH oxidase (NOX) and myeloperoxidase (MPO). This ROS overproduction is mediated by phosphorylation of the NOX subunits in an uncontrolled manner. Therefore, targeting neutrophil subunits would represent a promising strategy to moderate NOX activity, lower ROS, and other inflammatory agents, such as cytokines and leukotrienes, produced by neutrophils. For this purpose, we investigated the effects of protectin DX (PDX)-a docosahexaenoic acid di-hydroxylated product which inhibits blood platelet aggregation-on neutrophil activation in vitro. We found that PDX decreases ROS production, inhibits NOX activation and MPO release from neutrophils. We also confirm, that PDX is an anti-aggregatory and anti-inflammatory agent by inhibiting both cyclooxygenase-1 and -2 (COX-1 and COX-2, E.C. 1.14.99.1) as well as COX-2 in lipopolysaccharides-treated human neutrophils. However, PDX has no effect on the 5-lipoxygenase pathway that produces the chemotactic agent leukotriene B4 (LTB4). Taken together, our results suggest that PDX could be a protective agent against neutrophil invasion in chronic inflammatory diseases.

The trans-10,cis-15 18:2: a Missing Intermediate of trans-10 Shifted Rumen Biohydrogenation Pathway?

Abstract: The “trans-10 shifted” biohydrogenation pathway is frequently established in the rumen when high starch diets are fed to ruminants, resulting in the accumulation of trans-10 18:1 in ruminant products. It has been proposed that the “trans-10 shifted” biohydrogenation pathway of α-linolenic acid generates two intermediates, the trans-10,cis-15 18:2 and trans-10,cis-12,cis-15 18:3, although none of these have been found in the rumen. We analyzed digestive contents and meat samples from two trials, where animals were fed: a compound feed diet supplemented with 8 % oil blend containing linseed oil (samples A); and a forage based diet supplemented with 6 % linseed oil (samples B). The use of the new SLB-IL111 chromatographic column allowed the detection of two different 18:2 isomers in each sample trial, which could not be resolved when the CP-Sil 88 column is used. The two 18:2 isomers were characterized by mass spectrometry using 4,4-dimethyloxazoline derivatives. However, because they were subject to higher temperatures and present different chromatographic properties compared with the fatty acid methyl esters, we also used the “covalent adduct chemical ionization” technique to confirm the identity of both 18:2 isomers. We detected and identified the 10,15-18:2 in samples A and the 11,15-18:2 in samples B. The geometry of both isomers was tentatively assigned as trans,cis taking in account their elution order and biologic plausibility. As far as we know, this is the first time that the trans-10,cis-15 18:2 has been found in ruminant digestive contents and meat samples associated with the “trans-10 shifted” biohydrogenation pathway of α-linolenic acid.

Effects of a diet rich in n-3 polyunsaturated fatty acids on hepatic lipogenesis and beta-oxidation in mice.

Abstract: Here, we investigate whether a diet rich in fish oil can lead to the development of hepatic alterations associated with non-alcoholic fatty liver disease (NAFLD). To achieve this goal, we provided, for 8 weeks, four different diets to 3-month-old C57BL/6 mice: (a) standard-chow diet (SC; 40 g soybean oil/kg diet, 10 % of the total energy content from lipids), (b) fish oil diet (FO; 4 g soybean oil and 36 g fish oil/kg diet, 10 % of the total energy content from lipids), (c) high-fat diet (HF; 40 g soybean oil and 238 g lard/kg diet, 50 % of the total energy content from lipids), and (d) high-fish oil diet (HFO; 40 g soybean oil and 238 g fish oil/kg diet, 50 % of the total energy content from lipids). Biochemical analyses, stereology, western-blotting and RT-qPCR were used. In the HF group, we found evidence of obesity, metabolic syndrome, and liver damage, along with hypertriglyceridemia, hepatic insulin resistance, and steatosis. On the other hand, the HFO group did not present these alterations and remained similar to the controls. The changes observed in the animals fed the HF diet were accompanied by an increase in hepatic lipogenesis and a decrease in beta-oxidation; meanwhile, in the HFO group, the opposite results were found, that is, reduced lipogenesis and elevated beta-oxidation, were most likely responsible for the prevention of deleterious hepatic alterations and liver damage. In conclusion, a diet rich in fish oil has beneficial effects on hepatic insulin resistance, lipogenesis and beta-oxidation and prevents hepatic tissue from liver damage and NAFLD.

Determination and Structural Elucidation of Triacylglycerols in Krill Oil by Chromatographic Techniques

Abstract: The content of triacylglycerols (TAG) in krill oil is generally omitted from the labels of commercial supplements and unacknowledged in studies aimed at proving its health benefits. The present study demonstrates that TAG compounds, in addition to phospholipids and lysophospholipids, are an important lipid class in pure krill oil. The fatty acid composition of TAG molecules from krill oil and their distribution on the backbone of TAG structures were determined by gas chromatography and liquid chromatography tandem mass spectrometric, respectively. The content of omega 3 polyunsaturated fatty acids (n-3 PUFA) was similar to those reported in the literature for fish oil. It was estimated that 21 % of n-3 PUFA were at the sn-2 position of TAG structures. To our knowledge, this is the first determination and structural characterization of TAG in pure krill oil supplements.

Plasma Levels of 14:0, 16:0, 16:1n‐7, and 20:3n‐6 are Positively Associated, but 18:0 and 18:2n‐6 are Inversely Associated with Markers of Inflammation in Young Healthy Adults

Abstract: Inflammation is a recognized risk factor for the development of chronic diseases, such as type 2 diabetes and atherosclerosis. Evidence suggests that individual fatty acids (FA) may have distinct influences on inflammatory processes. The goal of this study was to conduct a cross-sectional analysis to examine the associations between circulating FA and markers of inflammation in a population of young healthy Canadian adults. FA, high-sensitivity C-reactive protein (hsCRP), and cytokines were measured in fasted plasma samples from 965 young adults (22.6 ± 0.1 years). Gas chromatography was used to measure FA. The following cytokines were analyzed with a multiplex assay: regulated upon activation normal T cell expressed and secreted (RANTES/CCL5), interleukin 1-receptor antagonist (IL-1Ra), interferon-γ (IFN-γ), interferon-γ inducible protein 10 (IP-10), and platelet-derived growth factor β (PDGF-ββ). Numerous statistically significant associations (p < 0.05, corrected for multiple testing) were identified between individual FA and markers of inflammation using linear regression. Myristic (14:0), palmitic (16:0), palmitoleic (16:1n-7), and dihomo-γ-linolenic (20:3n-6) acids were positively associated with all markers of inflammation. In contrast, stearic acid (18:0) was inversely associated with hsCRP and RANTES, and linoleic acid (18:2n-6) was inversely associated with hsCRP, RANTES and PDGF-ββ. In conclusion, our results indicate that specific FA are distinctly correlated with various markers of inflammation. Moreover, the findings of this study suggest that FA profiles in young adults may serve as an early indicator for the development of future complications comprising an inflammatory component.

Microglial Cell Activation Increases Saturated and Decreases Monounsaturated Fatty Acid Content, but Both Lipid Species are Proinflammatory

Abstract: Neuroinflammation is a component of age-related neurodegenerative diseases and cognitive decline. Saturated (SFA) and monounsaturated (MUFA) fatty acids are bioactive molecules that may play different extrinsic and intrinsic roles in neuroinflammation, serving as exogenous ligands for cellular receptors, or endogenous components of cell structural, energetic and signaling pathways. We determined the fatty acyl profile of BV2 microglial cells before and after acute activation with lipopolysaccharide (LPS). We also investigated the effect of SFA and MUFA pretreatment on the production of an invasive, neurotoxic phenotype in BV2 cells. Acute activation of BV2 microglia resulted in an increase in the relative content of SFA (12:0, 16:0, 18:0, 20:0, 22:0, and 24:0 increased significantly), and a relative decrease in the content of MUFA (16:1n7, 18:1n7, 18:1n9, 20:1n9, 24:1n9 decreased significantly). In agreement, the major stearoyl-CoA desaturase (SCD) isoform in BV2 cells, SCD2, was significantly down-regulated by LPS. We next treated cells with SFA (16:0 or 18:0) or MUFA (16:1n7 or 18:1n9), and found that levels of secreted IL6 were increased, as was secreted MMP9-mediated proteolytic activity. To test the functional significance, we treated SH-SY5Y neuronal cells with conditioned medium from BV2 cells pretreated with fatty acids, and found a small but significant induction of cell death. Our findings suggest differential intrinsic roles for SFA and MUFA in activated microglial cells, but similar extrinsic roles for these fatty acid species in inducing activation. Expansion of SFA is important during microglial cell activation, but either supplemental SFA or MUFA may contribute to chronic low-grade neuroinflammation.

Fatty Acid Profiles of Commercially Available Finfish Fillets in the United States

Abstract: Fillets of 76 finfish species (293 composites of three fish) were obtained from commercial seafood vendors in six regions of the United States (i.e., Great Lakes, Mid-Atlantic, New England, Northwest, Southeast, and Southwest). Full fatty acid profiles were determined for each species and are presented here. Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have been associated with many health benefits. Thus, fillets of each species were compared for total EPA plus DHA content, which ranged from 17 mg/100 g (pangasius/swai) to 2430 mg/100 g (Chilean sea bass). Of the top ten most popularly consumed seafoods in the US, finfish, including salmon species (717-1533 mg/100 g), Alaskan pollock (236 mg/100 g), tilapia (76 mg/100 g), channel catfish (44 mg/100 g), Atlantic cod (253 mg/100 g), and pangasius/swai (17 mg/100 g), exhibited a wide concentration range of EPA plus DHA. Large variances were found within many of the farmed species analyzed, which likely stems from dietary differences in the farm-fed diet. The results of this study provide current information on a broad range of species and will help nutritionists and the public make informed decisions regarding seafood consumption.

Gut Microbial Metabolites of Polyunsaturated Fatty Acids Correlate with Specific Fecal Bacteria and Serum Markers of Metabolic Syndrome in Obese Women

Abstract: The aim of this human study was to assess the influence of prebiotic-induced gut microbiota modulation on PUFA-derived bacterial metabolites production. Therefore, we analyzed the circulating fatty acid profile including CLA/CLnA in obese women treated during 3 months with inulin-type fructan prebiotics. In these patients, we had already determined gut microbiota composition by phylogenetic microarray and qPCR analysis of 16S rDNA. Some PUFA-derived bacterial metabolites were detected in the serum of obese patients. Despite the prebiotic-induced modulation of gut microbiota, including changes in CLA/CLnA-producing bacteria, the treatment did not impact significantly on the circulating level of these metabolites. However, some PUFA-derived bacterial metabolites were positively correlated with specific fecal bacteria (Bifidobacterium spp., Eubacterium ventriosum and Lactobacillus spp.) and inversely correlated with serum cholesterol (total, LDL, HDL). These correlations suggest a potential beneficial effect of some of these metabolites but this remains to be confirmed by further investigation.

Fatty Acid-Specific Alterations in Leptin, PPARα, and CPT-1 Gene Expression in the Rainbow Trout

Abstract: It is known that fatty acids (FA) regulate lipid metabolism by modulating the expression of numerous genes. In order to gain a better understanding of the effect of individual FA on lipid metabolism related genes in rainbow trout (Oncorhynchus mykiss), an in vitro time-course study was implemented where twelve individual FA (butyric 4:0; caprylic 8:0; palmitic (PAM) 16:0; stearic (STA) 18:0; palmitoleic16:1n-7; oleic 18:1n-9; 11-cis-eicosenoic 20:1n-9; linoleic (LNA) 18:2n-6; α-linolenic (ALA) 18:3n-3; eicosapentenoic (EPA) 20:5n-3; docosahexaenoic (DHA) 22:6n-3; arachidonic (ARA) 20:4n-6) were incubated in rainbow trout liver slices. The effect of FA administration over time was evaluated on the expression of leptin, PPARα and CPT-1 (lipid oxidative related genes). Leptin mRNA expression was down regulated by saturated fatty acids (SFA) and LNA, and was up regulated by monounsaturated fatty acids (MUFA) and long chain PUFA, whilst STA and ALA had no effect. PPARα and CPT-1mRNA expression were up regulated by SFA, MUFA, ALA, ARA and DHA; and down regulated by LNA and EPA. These results suggest that there are individual and specific FA induced modifications of leptin, PPARα and CPT-1 gene expression in rainbow trout, and it is envisaged that such results may provide highly valuable information for future practical applications in fish nutrition.

Longitudinal Evolution of the Concentration of Gangliosides GM3 and GD3 in Human Milk

Abstract: It has been reported that dietary gangliosides may have an important role in preventing infections and in brain development during early infancy. However, data related to the evolution of their concentration over the different stages of lactation are scarce. Liquid chromatography coupled with electrospray ionization high resolution mass spectrometer (LC/ESI-HR-MS) has been optimized to quantify the two major ganglioside classes, i.e., aNeu5Ac(2-8)aNeu5Ac(2-3)bDGalp(1-4)bDGlcp(1-1)Cer (GD3) and aNeu5Ac(2-3)bDGalp(1-4)bDGlcp(1-1)Cer (GM3) in human milk. Gangliosides were extracted using chloroform and methanol, further purified by solid-phase extraction and separated by reversed-phase liquid chromatography. Repeatability, intermediate reproducibility, and recovery values were assessed to validate the method. In human milk, GD3 and GM3 could be quantified at the level of 0.1 and 0.2 μg/mL, respectively, with relative standard deviation of repeatability [CV(r)] and intermediate reproducibility [CV(iR)] values ranging from 1.9 to 15.0 % and 1.9 to 22.5 %, respectively. The described method was used to quantify GD3 and GM3 in human milk samples collected from 450 volunteers between 0 and 11 days and at 30, 60 and 120 days postpartum, providing for the first time the concentration of these minor lipids in a large cohort. The content of total gangliosides ranged from 8.1 and 10.7 μg/mL and the mean intake of gangliosides in infants 30, 60 and 120 days postpartum could be estimated at about 5.5, 7.0 and 8.6 mg of total gangliosides per day, respectively, when infants were exclusively breastfed.

Vitamin E conditionally inhibits atherosclerosis in ApoE knockout mice by anti-oxidation and regulation of vasculature gene expressions.

Abstract: Lipid deposition in artery walls is implied in the pathogenesis of atherosclerosis and imbalance between uptake and efflux of cholesterol favors the deposition. We investigated the effect of vitamin E with the same dose and duration on the different stages of atherosclerosis in Apolipoprotein E knockout (ApoE KO) mice and explored the potential mechanisms. The results showed that the ApoE KO mouse spontaneously develops atherosclerosis in an age-dependent manner from 14 to 46 weeks on the regular chow. Vitamin E (100 mg/kg) supplementation to ApoE KO mice at 6, 14, and 22 weeks for 8 weeks significantly reduced the atherosclerotic lesion area by 41, 29 and 19 % respectively compared to the age-matched control mice; however had no significant effect on the lesion when given at 30 and 38 weeks. In addition, vitamin E supplemented at the ages from 6 to 30 weeks decreased the contents of serum oxLDL and TBARS without affecting the TC and TAG contents in serum and liver. Furthermore, vitamin E supplemented at 6, 14 and 22 weeks down-regulated vasculature mRNA expressions of scavenger receptor CD36 and up-regulated mRNA expressions of PPARγ, LXRα and ABCA1 which are involved in reverse cholesterol transportation; however had no significant effects on these genes when given at 30 and 38 weeks. In conclusion, vitamin E with same dose and duration inhibits the early but not advanced atherosclerotic lesion in ApoE KO mice by anti-oxidation and regulation of mRNA expression of genes involved in cholesterol uptake and efflux, which favors the improvement of atherosclerosis.

Enhanced Solubility and Oral Bioavailability of γ-Tocotrienol Using a Self-Emulsifying Drug Delivery System (SEDDS)

Abstract: The aim of this study was to evaluate the in vitro and in vivo performance of γ-tocotrienol (γ-T3) incorporated in a self-emulsifying drug delivery system (SEDDS) and to compare its enhanced performance to a commercially available product, namely Tocovid Suprabio™ (hereafter Tocovid), containing tocotrienols. The solubilization of γ-T3 was tested in a dynamic in vitro lipolysis model followed by in vitro cellular uptake study for the lipolysis products. In addition, in vitro uptake studies using Caco2 cells were conducted at different concentrations of γ-T3 prepared as SEDDS, Tocovid, or mixed micelles. γ-T3 incorporated in SEDDS or Tocovid was orally administered to rats at different doses and absolute oral bioavailability from both formulations were determined. The dynamic in vitro lipolysis experiment showed about two fold increase in the solubilization of γ-T3 prepared as SEDDS compared to Tocovid, which correlated with higher cellular uptake in the subsequent uptake studies. In vitro cellular uptake and in vivo oral bioavailability studies have shown a twofold increase in the cellular uptake and oral bioavailability of γ-T3 incorporated in SEDDS compared to Tocovid as a result of improvement in its solubility and passive uptake as confirmed by in vitro studies. In conclusion, incorporation of γ-T3 in SEDDS formulation enhanced γ-T3 solubilization and passive permeability, thus its cellular uptake and oral bioavailability when compared to Tocovid.

PCSK9 is Present in Human Cerebrospinal Fluid and is Maintained at Remarkably Constant Concentrations Throughout the Course of the Day

Abstract: Proprotein convertase subtilisin kexin type 9 (PCSK9) is a key regulator of serum low density lipoprotein cholesterol levels. PCSK9 is secreted by the liver and binds the hepatic low density lipoprotein receptor, causing its subsequent degradation. PCSK9 has also been shown to regulate the levels of additional membrane-bound proteins in vitro, including very low-density lipoprotein receptor, apolipoprotein E receptor 2, and beta-site amyloid precursor protein-cleaving enzyme 1, which are highly expressed in central nervous system (CNS) and have been implicated in Alzheimer’s disease. Previous studies have demonstrated that human circulating PCSK9 displays a diurnal rhythm. Currently, little is known about PCSK9 levels in human cerebrospinal fluid (CSF). In the present study, we measured PCSK9 concentrations in both serum and CSF collected from healthy human subjects at multiple time points throughout the day. While PCSK9 in serum manifested a distinct diurnal pattern, CSF PCSK9 levels were remarkably constant throughout the course of the day and were also consistently lower than corresponding serum PCSK9 concentrations. Our results indicate that regulation of PCSK9 in human CSF may be different than for plasma PCSK9, suggesting that further study of the role of PCSK9 in the CNS is warranted.

Synbiotic Food Consumption Reduces Levels of Triacylglycerols and VLDL, but not Cholesterol, LDL, or HDL in Plasma from Pregnant Women

Abstract: To our knowledge, no reports are available indicating the effects of synbiotic food consumption on blood lipid profiles and biomarkers of oxidative stress among pregnant women. This study was conducted to evaluate the effects of daily consumption of a synbiotic food on blood lipid profiles and biomarkers of oxidative stress in pregnant women. This randomized, double-blind, controlled clinical trial was performed among 52 primigravida pregnant women, aged 18 to 35-year-old at their third trimester. After a 2-week run-in period, subjects were randomly assigned to consume either a synbiotic (n = 26) or control food (n = 26) for 9 weeks. The synbiotic food consisted of a probiotic viable and heat-resistant Lactobacillus sporogenes (1 × 107 CFU) and 0.04 g inulin (HPX)/g as the prebiotic. Patients were asked to consume the synbiotic and control foods two times a day. Biochemical measurements including blood lipid profiles, plasma total antioxidant capacity (TAC) and total glutathione (GSH) were conducted before and after 9 weeks of intervention. Consumption of a synbiotic food for 9 weeks resulted in a significant reduction in serum TAG (P = 0.04), VLDL (P = 0.04) and a significant rise in plasma GSH levels (P = 0.004) compared to the control food. No significant effects of the synbiotic food consumption on serum TC, LDL, HDL and plasma TAC levels (P > 0.05) were observed. Trial registry code: http://www.irct.ir. IRCT201212105623N3.

Four Amino Acid Residues Influence the Substrate Chain-Length and Regioselectivity of Siganus canaliculatus Δ4 and Δ5/6 Desaturases

Abstract: Although ω3- and ω6- desaturases have been well studied in terms of substrate preference and regiospecificity, relatively little is known about the membrane-bound, “front-end” long chain fatty acid desaturases, such as ∆4, Δ5 or Δ6 desaturases. The first vertebrate ∆4 desaturase was recently identified in the marine teleost fish Siganus canaliculatus (S. canaliculatus), which also possesses a bifunctional Δ5/6 desaturase. These two long chain polyunsaturated fatty acid desaturases are very different in terms of regiospecificity and substrate chain-length, but share an unusually high degree of amino acid identity (83 %). We took advantage of this similarity by constructing a series of chimeric enzymes, replacing regions of one enzyme with the corresponding sequence of the other. Heterologous expression of the chimeric series of enzymes in yeast indicated that the substitution of a four amino acid region was sufficient to convert a ∆4 desaturase to an enzyme with ∆6 desaturase activity, and convert a ∆5/6 desaturase to an enzyme with a low level of ∆4 desaturase activity. In addition, enzymes having both ∆4 and ∆6 desaturase activities were produced by single or double amino acid substitutions within this four-amino acid region.

Autoxidative and Photooxidative Reactivity of Highly Branched Isoprenoid (HBI) Alkenes

Abstract: Autoxidation of several mono-, di-, tri- and tetra-unsaturated highly branched isoprenoid (HBI) alkenes was induced in organic solvents using a radical initiator and enhancer, and their degradation rates were compared to those of classical phytoplanktonic lipids (mono-unsaturated fatty acids, sterols and chlorophyll phytyl side-chain). Autoxidation of two HBI trienes was also investigated in senescent and highly photodegraded diatom cells, collected in the Antarctic, using Fe2+ ions as radical inducers. Autoxidation rates of HBI alkenes were found to increase with the number of tri-substituted double bonds, as expected. Further, HBI trienes possessing one bis-allylic position (where hydrogen abstraction is highly favoured) were found to be particularly reactive towards autoxidation and degraded at similar rates compared to polyunsaturated fatty acids in diatom cells. By comparison of the autoxidation products of the most reactive tri-unsaturated HBI with the corresponding photooxidation products, some specific tracers of these two types of abiotic degradation processes were identified. The lack of reactivity of the mono-unsaturated HBI IP25 and a structurally similar di-unsaturated HBI towards autoxidative degradation supports the good preservation of these biomarkers in marine sediments.

Phospholipid Transfer Protein Deficiency Decreases the Content of S1P in HDL via the Loss of its Transfer Capability

Abstract: Sphingosine-1-phosphate (S1P) is an amphiphilic signaling molecule, which is enriched in functional high density lipoprotein (HDL) and shows arterial protection. The distribution of S1P is changed with increased plasma phospholipid transfer protein (PLTP) activity and impaired HDL function in patients with coronary heart diseases. Therefore, we hypothesized that PLTP might transfer S1P among cells or lipoproteins. We found that plasma S1P contents were decreased by 60.1 % in PLTP knockout mice (PLTP−/−, N = 5) compared with their wild type littermates (WT, N = 5) (151.70 ± 38.59 vs. 379.32 ± 59.90 nmol/l, P<0.01). S1P content in HDL fraction (HDL-S1P) from PLTP−/− was decreased by 64.7 % compared with WT (49.36 ± 1.49 vs. 139.76 ± 2.94 nmol/l, P<0.01). The results of the S1P transfer assay indicated that PLTP could facilitate S1P transport from erythrocytes to HDL at 37 °C in D-Hanks buffer. Plasma content of apolipoprotein M, a specific adaptor of S1P, was not changed in PLTP−/− compared with WT. Therefore, we concluded that PLTP was a key factor to maintain plasma HDL-S1P, and PLTP deficiency could decrease the S1P content in plasma lipoproteins, which involves its capability of transferring S1P from erythrocyte to HDL.

Tocotrienol Rich Fraction Reverses Age-Related Deficits in Spatial Learning and Memory in Aged Rats

Abstract: Little is known about the effect of vitamin E on brain function. Therefore, in this study we evaluated the effect of tocotrienol rich fraction (TRF) on behavioral impairment and oxidative stress in aged rats. Thirty-six male Wistar rats (young: 3-months-old; aged: 21-months-old) were treated with either the control (olive oil) or TRF (200 mg/kg) for 3 months. Behavioral studies were performed using the open field test and Morris water maze (MWM) task. Blood was taken for assessment of DNA damage, plasma malondialdehyde (MDA) and vitamin E, and erythrocyte antioxidant enzyme activity. Brains were also collected to measure vitamin E levels. Results showed that aged rats exhibited reduced exploratory activity, enhanced anxiety and decreased spatial learning and memory compared with young rats. DNA damage and plasma MDA were increased, and vitamin E levels in plasma and brain were reduced in aged rats. Aged rats supplemented with TRF showed a markedly reduced level of anxiety, improved spatial learning and memory, reduced amount and severity of DNA damage, a reduced level of MDA, and increased levels of antioxidant enzyme activity and plasma/brain vitamin E compared with age-matched controls. In conclusion, TRF supplementation reverses spatial learning and memory decline and decreases oxidative stress in aged rats.

Lipidomics Reveals Mitochondrial Membrane Remodeling Associated with Acute Thermoregulation in a Rodent with a Wide Thermoneutral Zone

Abstract: Mongolian gerbils (Meriones unguiculatus) have high physiological flexibility in response to acute temperature changes, and have the widest thermoneutral zone (TNZ, 265-389 C) reported among small mam- mals At the upper critical temperature (Tuc ,3 89C), body temperatures of gerbils were significantly increased (39-41 C) while metabolic rates were maintained at the basal level In contrast, below the lower critical tempera- ture (Tlc, 265 C), metabolism was elevated and body temperature stable Rapid changes in mitochondrial mem- brane lipidome were hypothesized to play an important role during acute thermoregulation of gerbils Taking advantage of a recent lipidomic technique, we examined changes in the membrane phospholipids environment and free fatty acids (FFA) production in mitochondria between 38 and 27 C (in the TNZ), and between 27 and 16 C (below the TNZ) At 38 C, acute heat stress elicited distinct remod- eling in mitochondrial membrane lipidome which related to a potential decrease in mitochondrial respiration and membrane fluidity compared to 27 C At 16 C, a sharply decreased unsaturation index and increased chain lengths were detected in mitochondrial FFA production both in muscle and brown adipose tissue Our results suggest that mitochondrial membrane lipid remodeling may stabilize membrane function and activity of respiration related membrane protein to maintain a stable metabolic rate at Tuc, and improve heat production by decomposing less fluid fatty acid conjugates of membrane lipids under acute cold exposure These data therefore imply an important role of membrane remodeling during acute thermoregula- tion in a non-hibernating endotherm

Effect of compounds affecting ABCA1 expression and CETP activity on the HDL pathway involved in intestinal absorption of lutein and zeaxanthin.

Abstract: The antioxidant xanthophylls lutein and zeaxanthin are absorbed from the diet in a process involving lipoprotein formation. Selective mechanisms exist for their intestinal uptake and tissue-selective distribution, but these are poorly understood. We investigated the role of high-density lipoprotein (HDL), apolipoprotein (apo) A1 and ATP-binding cassette transporter (ABC) A1 in intestinal uptake of lutein in a human polarized intestinal cell culture and a hamster model. Animals received dietary lutein and zeaxanthin and either a liver X receptor (LXR) agonist or statin, which up- or down-regulate intestinal ABCA1 expression, respectively. The role of HDL was studied following treatment with the cholesteryl ester transfer protein (CETP) modulator dalcetrapib or the CETP inhibitor anacetrapib. In vitro, intestinal ABCA1 at the basolateral surface of enterocytes transferred lutein and zeaxanthin to apoA1, not to mature HDL. In hamsters, plasma lutein and zeaxanthin levels were markedly increased with the LXR agonist and decreased with simvastatin. Dalcetrapib, but not anacetrapib, increased plasma and liver lutein and zeaxanthin levels. ABCA1 expression and apoA1 acceptor activity are important initial steps in intestinal uptake and maintenance of lutein and zeaxanthin levels by an HDL-dependent pathway. Their absorption may be improved by physiological and pharmacological interventions affecting HDL metabolism.

Retroconversion of Docosapentaenoic Acid (n-6): an Alternative Pathway for Biosynthesis of Arachidonic Acid in Daphnia magna

Abstract: The aim of this study was to assess metabolic pathways for arachidonic acid (20:4n-6) biosynthesis in Daphnia magna. Neonates of D. magna were maintained on [13C] enriched Scenedesmus obliquus and supplemented with liposomes that contained separate treatments of unlabeled docosapentaenoic acid (22:5n-6), 20:4n-6, linoleic acid (18:2n-6) or oleic acid (18:1n-9). Daphnia in the control treatment, without any supplementary fatty acids (FA) containing only trace amounts of 20:4n-6 (~0.3 % of all FA). As expected, the highest proportion of 20:4n-6 (~6.3 %) was detected in Daphnia that received liposomes supplemented with this FA. Higher availability of 18:2n-6 in the diet increased the proportion of 18:2n-6 in Daphnia, but the proportion of 20:4n-6 was not affected. Daphnia supplemented with 22:5n-6 contained ~3.5 % 20:4n-6 in the lipids and FA specific stable isotope analyses validated that the increase in the proportion of 20:4n-6 was due to retroconversion of unlabeled 22:5n-6. These results suggest that chain shortening of 22:5n-6 is a more efficient pathway to synthesize 20:4n-6 in D. magna than elongation and desaturation of 18:2n-6. These results may at least partially explain the discrepancies noticed between phytoplankton FA composition and the expected FA composition in freshwater cladocerans. Finally, retroconversion of dietary 22:5n-6 to 20:4n-6 indicates Daphnia efficiently retain long chain n-6 FA in lake food webs, which might be important for the nutritional ecology of fish.

Alterations in Membrane Phospholipid Fatty Acids of Gram‐Positive Piezotolerant Bacterium Sporosarcina sp. DSK25 in Response to Growth Pressure

Abstract: Pressure is an important thermodynamic property of the ocean and the deep biosphere that affects microbial physiology and biochemistry. Here, we report on our investigation of the response of Gram-positive piezotolerant bacterium Sporosarcina sp. DSK25 to hydrostatic pressure. Strain DSK25 responded in an adaptive manner to upshifts of growth pressure and showed systematic changes in phospholipid fatty acids. As the pressure increased from 0.1 to 10 MPa (Megapascal), unsaturated fatty acids in DSK25 increased from 21.7 to 31.1 % of total fatty acids, while the level of iso- and anteiso-branched fatty acids remained unchanged. At higher pressures (30, 50, and 60 MPa), the amount of unsaturated fatty acids decreased, and that of anteiso-branched fatty acids increased from 34.4 to 49.9 % at the expense of iso-branched fatty acids. For the first time, two polyunsaturated fatty acids (PUFA), 18:2n-6 and 18:2n-x, with the latter having much higher abundance than the former, were identified in DSK25. The concentration of the PUFA increased with growth pressure. These results indicate the involvement of unsaturated and methyl-branched fatty acids in the modulation of bacteria membrane fluidity and function over environmentally relevant parameter (pressure). Piezotolerant bacterium Sporosarcina sp. DSK25 appears to utilize two regulatory mechanisms for adaptation to high pressure, a rapid-responding mechanism on transient scale, expressed as increased biosynthesis of monounsaturated fatty acids, and a long-term adaptation mechanism in increased synthesis of anteiso-branched and polyunsaturated fatty acids. Our results further suggest that Gram-positive piezophilic bacteria respond differently than Gram-negative bacteria in adaptation to high pressure.

Rumen metabolism of 22:6n-3 in vitro is dependent on its concentration and inoculum size, but less dependent on substrate carbohydrate composition.

Abstract: Ruminal disappearance of linoleic and linolenic acid has been studied extensively. Less is known of the metabolism of docosahexaenoic acid (22:6n-3). The aim of this study was to identify factors which affect the disappearance of 22:6n-3 during in vitro batch incubations using rumen fluid from sheep. In experiment 1, the effect of the rumen fluid/buffer ratio (0.2 or 0.4), substrate (cellulose or cellulose/glucose), time of 22:6n-3 addition (0.08 mg/mL after 0 or 6 h of incubation) and incubation time (24 or 48 h) was evaluated. A mixture design was used in experiment 2 to evaluate the effect of carbohydrate type (cellulose, glucose, cellobiose and starch) on 22:6n-3 disappearance (0.08 mg/mL). In experiment 3, several concentrations of 22:6n-3 (0.05–0.30 mg/mL) were evaluated with different substrate mixtures (combinations of cellobiose, starch and cellulose). In a final experiment, the effect of the rumen fluid/buffer ratio (0.20, 0.35 and 0.50) and substrate (glucose, cellobiose and starch) was evaluated. In this experiment, 22:6n-3 was added as a proportion of rumen fluid ranging from 0.1 to 0.4 mg/mL rumen fluid, contrary to former experiments where concentrations were relative to culture medium. Low levels of 22:6n-3 (0.05 mg/mL) allowed extensive metabolism whereas increasing amounts of 22:6n-3 hampered its disappearance. A greater proportion of rumen fluid resulted in increased disappearance of 22:6n-3. The effect of carbohydrate type was small compared with the former two factors. These results suggest that in vitro metabolism of 22:6n-3 is mostly dictated by the conditions at the start of the incubation, i.e., inoculum, probably reflecting the density of bacteria able to metabolize 22:6n-3.

Elaidic Acid Increases Hepatic Lipogenesis by Mediating Sterol Regulatory Element Binding Protein-1c Activity in HuH-7 Cells

Abstract: The liver is the major organ responsible for lipid biosynthesis. Sterol regulatory element-binding proteins (SREBP) are major transcription factors that regulate the expression of genes regulating fatty acid and cholesterol biosynthesis. Here we show that elaidic acid upregulates hepatic de-novo fatty acid and cholesterol synthesis in HuH-7 cells. To define the molecular mechanism involved in this unique regulation on hepatic lipogenesis, luciferase reporter gene assays were performed in HEK293 cells to compare the regulation of sterol regulatory element (SRE) that is present in SREBP-target promoter by elaidic acid and oleic acid. The results show that elaidic acid potently induced SRE-luciferase activity, whereas oleic acid inhibited this activity. Furthermore, elaidic acid increased SREBP-1c mRNA, while oleic acid did not alter it. Oleic acid inhibited mature form of SREBP-1 protein level, while elaidic acid did not show inhibitory effects. In addition, elaidic acid was also found to increase several selected lipogenic genes that are involved in fatty acids and sterol synthesis. These data demonstrate a unique role of elaidic acid, the most abundant trans fatty acid, in modulating hepatic lipogenesis.

Hydroxyoctadecadienoic acids regulate apoptosis in human THP-1 cells in a PPARγ-dependent manner.

Abstract: Macrophage apoptosis, a key process in atherogenesis, is regulated by oxidation products, including hydroxyoctadecadienoic acids (HODEs). These stable oxidation products of linoleic acid (LA) are abundant in atherosclerotic plaque and activate PPARγ and GPR132. We investigated the mechanisms through which HODEs regulate apoptosis. The effect of HODEs on THP-1 monocytes and adherent THP-1 cells were compared with other C18 fatty acids, LA and α-linolenic acid (ALA). The number of cells was reduced within 24 hours following treatment with 9-HODE (p < 0.01, 30 μM) and 13 HODE (p < 0.01, 30 μM), and the equivalent cell viability was also decreased (p < 0.001). Both 9-HODE and 13-HODE (but not LA or ALA) markedly increased caspase-3/7 activity (p < 0.001) in both monocytes and adherent THP-1 cells, with 9-HODE the more potent. In addition, 9-HODE and 13-HODE both increased Annexin-V labelling of cells (p < 0.001). There was no effect of LA, ALA, or the PPARγ agonist rosiglitazone (1μM), but the effect of HODEs was replicated with apoptosis-inducer camptothecin (10μM). Only 9-HODE increased DNA fragmentation. The pro-apoptotic effect of HODEs was blocked by the caspase inhibitor DEVD-CHO. The PPARγ antagonist T0070907 further increased apoptosis, suggestive of the PPARγ-regulated apoptotic effects induced by 9-HODE. The use of siRNA for GPR132 showed no evidence that the effect of HODEs was mediated through this receptor. 9-HODE and 13-HODE are potent—and specific—regulators of apoptosis in THP-1 cells. Their action is PPARγ-dependent and independent of GPR132. Further studies to identify the signalling pathways through which HODEs increase apoptosis in macrophages may reveal novel therapeutic targets for atherosclerosis.

The β-subunit of cholera toxin has a high affinity for ganglioside GM1 embedded into solid supported lipid membranes with a lipid raft-like composition.

Abstract: In this communication, we report on the fabrication of GM1-rich solid-supported bilayer lipid membranes (ssBLM) made of sphingomyelin and cholesterol, the main components of lipid rafts, which are the physiological hosting microenvironment of GM1 on the cell membrane. The functionality of the ganglioside has been checked by measuring the apparent dissociation constant KD of the complex formed by the β-subunit of the cholera toxin and GM1. The value found deviates less than one order of magnitude from that measured for in vivo cells, indicating the potential of these ssBLM as optimized in vitro biomimetic platforms.