Acid Composition Of Plasma Lipids Research Articles

The FADS1 rs174550 Genotype Modifies the n-3 and n-6 PUFA and Lipid Mediator Responses to a High Alpha-Linolenic Acid and High Linoleic Acid Diets.

The fatty acid composition of plasma lipids, which is associated with biomarkers and risk of non-communicable diseases, is regulated by dietary polyunsaturated fatty acids(PUFAs) and variants of fatty acid desaturase (FADS). We investigated the interactions between dietary PUFAs and FADS1 rs174550 variant. Participants (n = 118), homozygous for FADS1 rs174550 variant (TT and CC) followed a high alpha-linolenic acid (ALA, 5 percent of energy (E-%)) or a high linoleic acid (LA, 10 E-%) diet during an 8-week randomized controlled intervention. Fatty acid composition of plasma lipids and PUFA-derived lipid mediators were quantified by gas and liquid chromatography mass spectrometry, respectively. The high-LA diet increased the concentration of plasma LA, but not its lipid mediators. The concentration of plasma arachidonic acid decreased in carriers of CC and remained unchanged in the TT genotype. The high-ALA diet increased the concentration of plasma ALA and its cytochrome P450-derived epoxides and dihydroxys, and cyclooxygenase-derived monohydroxys. Concentrations of plasma eicosapentaenoic acid and its mono- and dihydroxys increased only in TT genotype carriers. These findings suggest the potential for genotype-based recommendations for PUFA consumption, resulting in modulation of bioactive lipid mediators which can exert beneficial effects in maintaining health.

Fatty acid composition of plasma lipids in familial LCAT deficiency supports the formation of ACAT2-derived cholesteryl esters in humans

Background and Aims : Mutations in the LCAT gene cause Familial LCAT Deficiency (FLD,OMIM#245900), a rare metabolic disorder characterized by severe HDL deficiency, hypertriglyceridemia, and an increased unesterified to total cholesterol ratio. Despite the complete lack of LCAT activity, FLD cases have circulating cholesteryl esters (CE), thus representing a tool to analyze the origin of VLDL cholesteryl esters.

Plasma lipidome abnormalities in people with HIV initiating antiretroviral therapy

BackgroundDyslipidemia often accompanies human immunodeficiency virus (HIV) infection and antiretroviral therapy (ART). Lipid abnormalities likely contribute to increased cardiometabolic disease among people with HIV (PWH). Here, we expand our previous findings on changes in the lipidome following ART initiation, and associations among lipid species, including ceramides (CER), diacylglycerols (DAG), and triacylglycerols (TAG), with immune activation.MethodsConcentrations and fatty acid composition of plasma lipids (~ 1300 species) were measured by differential mobility spectroscopy in samples from 35 treatment-naïve PWH pre- and post-initiation of ART (raltegravir (RAL)/tenofovir disoproxil fumarate (TDF)/emtricitabine (FTC)); lipidomes were compared to those found in demographically similar HIV-uninfected individuals (n = 13).ResultsCompared to people without HIV, 37.1% of all lipid species measured were altered in PWH at baseline, and 31.8% of lipid species were altered following 48 weeks of ART. Concentrations of lipid classes were also altered in PWH; diacylglycerols (DAGs) and triacylglycerols (TAGs) were increased at baseline, and DAGs remained increased after 48 weeks of ART. Lipids previously linked to cardiovascular disease (CVD) and diabetes were enriched in PWH pre- and post ART, and were related to immune activation and insulin resistance scores. Polyunsaturated fatty acid (PUFA)-containing lipids were lower in PWH compared to levels in controls, and were inversely related to levels of inflammatory biomarkers.ConclusionsHIV infection and ART initiation both induce cardiometabolic changes to the composition of the plasma lipidome. These alterations are associated with inflammatory biomarkers, and may directly contribute to elevated CVD risk and diabetes.Trial registrationThis study is registered with Clinicaltrials.gov (NCT00660972). Registered April 16, 2008.

Inflammatory response to dietary linoleic acid depends on FADS1 genotype

The health benefits of substituting dietary polyunsaturated fatty acids (PUFAs) for saturated fatty acids are well known. However, limited information exists on how the response to dietary intake of linoleic acid (LA; 18:2n-6) is modified by polymorphisms in the fatty acid desaturase (FADS) gene cluster. The aim of the current study was to test the hypothesis that the FADS1 rs174550 genotype modifies the effect of dietary LA intake on the fatty acid composition of plasma lipids, fasting glucose, and high-sensitivity C-reactive protein (hsCRP). Associations were investigated between genotype, plasma PUFAs, fasting glucose, and hsCRP concentrations in the cross-sectional, population-based Metabolic Syndrome in Men cohort (n=1337). In addition, 62 healthy men from the cohort who were homozygotes for the TT or CC genotype of the FADS1 rs174550 were recruited to a 4-wk intervention (FADSDIET) with an LA-enriched diet. The fatty acid composition of plasma PUFAs and concentrations of plasma fasting glucose, serum hsCRP, and plasma lipid mediators (eicosanoids and related analogs) were measured at the beginning and end of the 4-wk intervention period. In the FADSDIET trial, the plasma LA proportion increased in both genotype groups in response to an LA-enriched diet. Responses in concentrations of serum hsCRP and plasma fasting glucose and the proportion of arachidonic acid (20:4n-6) in plasma phospholipids and cholesteryl esters differed between genotype groups (interaction of diet × genotype, P<0.05). In TT homozygous subjects, plasma eicosanoid concentrations correlated with the arachidonic acid proportion in plasma and with hsCRP (r=0.4-0.7, P<0.05), whereas in the CC genotype there were no correlations. Our findings show that the FADS1 genotype modifies metabolic responses to dietary LA. The emerging concept that personalized dietary counseling should be modified by the FADS1 genotype needs to be tested in larger randomized trials. The study was registered at clinicaltrials.gov as NCT02543216.

Genes and Dietary Fatty Acids in Regulation of Fatty Acid Composition of Plasma and Erythrocyte Membranes.

The fatty acid compositions of plasma lipids and cell membranes of certain tissues are modified by dietary fatty acid composition. Furthermore, many other factors (age, sex, ethnicity, health status, genes, and gene × diet interactions) affect the fatty acid composition of cell membranes or plasma lipid compartments. Therefore, it is of great importance to understand the complexity of mechanisms that may modify fatty acid compositions of plasma or tissues. We carried out an extensive literature survey of gene × diet interaction in the regulation of fatty acid compositions. Most of the related studies have been observational studies, but there are also a few intervention trials that tend to confirm that true interactions exist. Most of the studies deal with the desaturase enzyme cluster (FADS1, FADS2) in chromosome 11 and elongase enzymes. We expect that new genetic variants are being found that are linked with the genetic regulation of plasma or tissue fatty acid composition. This information is of great help to understanding the contribution of dietary fatty acids and their endogenic metabolism to the development of some chronic diseases.

Fatty acid compositions of plasma lipids in atopic dermatitis/asthma patients.

The proportions of linoleic acid in total plasma lipids and phospholipids were significantly greater and those of oleic acid were lower in pre-puberal and puberal atopic patients as compared with age-matched healthy controls. The n-3/n-6 fatty acid ratio of the triacylglycerol fraction was also lower in atopic patients. However, no significant decreases in the proportions of dihomo-gamma-linolenic acid and arachidonic acid were observed in plasma lipids of atopic patients, suggesting that delta 6-desaturase activity is not impaired in atopic patients. We provide an explanation for the beneficial effects of raising the n-3/n-6 ratio of dietary oils in the context of suppressing allergic hyper-reactivity in humans.

Abstract 1869: Plasma fatty acids and colorectal cancer risk: The Singapore Chinese Health Study

Abstract BACKGROUND: Fatty acids are a heterogeneous group of compounds that may promote or inhibit colorectal carcinogenesis. Fatty acid composition of plasma lipids capture dietary fat intake, as well as endogenous synthesis. Prospective analyses of fatty acid composition are needed to establish the role of long-chain monounsaturated and polyunsaturated fatty acids (PUFAs) on risk of developing colon cancer. METHODS:A nested case-control study of colon cancer (211 cases and 211 matched controls) was conducted within the Singapore Chinese Health Study, a cohort of 63,257 men and women ages 45 to 74 years who were recruited between 1993 and 1998. Fatty acids were quantified by gas chromatography-tandem mass spectrometry (GC-MS/MS) in plasma specimens that were collected an average of three years prior to colon cancer diagnosis. Desaturase activity was estimated as the product-to-precursor ratio of individual plasma fatty acids as follows: Δ5 desaturase = arachidonic (20:4n-6) to dihomo-γ-linolenic (20:3n-6) ratio, Δ6 desaturase = arachidonic (20:4n-6) to linoleic (18:2n-6) ratio, and stearoyl-coenzyme A desaturase (SCD-1) = oleic (18:1) to stearic (18:0) ratio. Conditional logistic regression was used to calculate multivariable odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS:Statistically significant inverse associations with colon cancer risk were observed for the essential PUFAs, α-linolenic (18:3n-3) (OR = 0.42; 95% CI: 0.24, 0.75) and linoleic (18:2n-6) (OR = 0.44; 95% CI: 0.23, 0.82), comparing highest to lowest quartile. There were no associations with the longer-chain n-3 PUFAs, eicosapentanoic (20:5n-3) and docosahexaenoic (22:6n-3). A positive association was observed with arachidonic acid (20:4n-6) and with elevated synthesis of arachidonic acid, as quantified by the Δ5 and Δ6 desaturase indices. Compared with the 1st quartile, the OR (95% CI) for the 4th quartile was 2.31 (1.30, 4.12) and 3.38 (1.76, 6.49) for Δ5 and Δ6 desaturase indices, respectively (both Ps for trend &amp;lt;0.03). Higher levels and elevated synthesis of oleic acid (18:1), as estimated by SCD-1 index were associated with statistically significant lower colon cancer risk. Compared with the lowest SCD-1 quartile, the OR was 0.43 (95% CI: 0.20, 0.92) for the highest quartile (P for trend = 0.024). CONCLUSION: These novel data suggest that endogenous synthesis of arachidonic and oleic acid may play a critical role in the risk of developing colon cancer in humans. Once confirmed, chemopreventive strategies may be developed as modulators of desaturase activity that result in lower arachidonic acid and higher oleic acid synthesis. GRANTS: UM1 CA182876 and R01 CA144034. Citation Format: Lesley M. Butler, Woon P. Koh, Jin Su, Renwei Wang, Choon N. Ong, Jian M. Yuan. Plasma fatty acids and colorectal cancer risk: The Singapore Chinese Health Study. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1869. doi:10.1158/1538-7445.AM2015-1869

Feasibility of Intermittent Fish Oil Infusions in Outpatients with Graft- Versus-Host Disease of the Digestive Tract

N-3 polyunsaturated fatty acids from fish oil may have immune-modulating effects in Graft-versus-Host Disease of the digestive tract (GVHD-DT). The objective of this pilot study was to investigate feasibility, safety and effects on fatty acid composition of plasma lipids and white blood cells (WBC), following intermittent fish oil infusion in outpatients with chronic GVHD-DT. Four outpatients received intermittent infusion of a 10% fish oil emulsion (Omegaven) during 4 hours, at day 1 (1.5 mL/kg), 3 (2.25 mL/kg) and 5, 8, 10 and 12 (3 mL/kg). At baseline and consecutive visits, fatty acid composition of plasma triglycerides (TG), plasma phospholipids (PL) and WBC, serum TG concentrations, routine laboratory tests, as well as adverse events were monitored. During the fish oil infusions, serum TG increased, but decreased 2 h after termination of infusion. In 3 patients, the dose of Omegaven® needed to be reduced. EPA was incorporated into plasma PL, plasma TG and WBC as of 2 days after the first infusion; peak levels of EPA were reached at the final infusion, or 2 days after. In conclusion, intermittent fish oil infusions result in incorporation of EPA in plasma and WBC, but can be complicated by a reversible increase in serum triglycerides.

Maternal plasma fatty acid composition and pregnancy outcome in adolescents

Adolescents are at a greater risk of adverse pregnancy outcome, including spontaneous preterm delivery and fetal growth restriction, and typically have a poorer-quality diet than adults have. In the present study, we addressed the hypothesis that low maternal dietary intake of n-3 long-chain PUFA (LCP) status adversely influences pregnancy outcome. A total of 500 adolescents (14-18 years) were recruited at ≤ 20 weeks' gestation. The frequency of consumption of oily fish was determined by questionnaire (at recruitment and during the third trimester). The fatty acid composition of plasma lipids during the third trimester was determined in 283 subjects. Principal components analysis (PCA) was used to derive components, which were divided into tertiles. The pregnancy outcomes were then compared by tertile, adjusting for potentially confounding variables. Of the participants, 69% reported never eating oily fish during pregnancy, although consumption was not associated with a shorter duration of gestation (P=0·33), lower customised birth weight (P=0·82) or higher incidence of small-for-gestational age (SGA) birth (P=0·55). PCA of the fatty acid composition of maternal plasma lipids identified a 'low PUFA:SFA (P:S) ratio' component and a 'high n-3 LCP' component. There were no differences between tertiles of the 'high n-3 LCP' component and gestational age at delivery (P=0·62), customised birth weight (P=0·38) or incidence of SGA birth (P=0·25), nor were there any associations between the 'low P:S' ratio component and pregnancy outcome. Lower proportions of n-3 LCP in plasma lipids are not associated with greater risk of adverse pregnancy outcomes in UK adolescents.

Maternal plasma fatty acid composition and pregnancy outcome in adolescents

Adolescents are at a greater risk of adverse pregnancy outcome, including spontaneous preterm delivery and fetal growth restriction, and typically have a poorer-quality diet than adults have. In the present study, we addressed the hypothesis that low maternal dietary intake of n-3 long-chain PUFA (LCP) status adversely influences pregnancy outcome. A total of 500 adolescents (14-18 years) were recruited at ≤ 20 weeks' gestation. The frequency of consumption of oily fish was determined by questionnaire (at recruitment and during the third trimester). The fatty acid composition of plasma lipids during the third trimester was determined in 283 subjects. Principal components analysis (PCA) was used to derive components, which were divided into tertiles. The pregnancy outcomes were then compared by tertile, adjusting for potentially confounding variables. Of the participants, 69% reported never eating oily fish during pregnancy, although consumption was not associated with a shorter duration of gestation (P=0·33), lower customised birth weight (P=0·82) or higher incidence of small-for-gestational age (SGA) birth (P=0·55). PCA of the fatty acid composition of maternal plasma lipids identified a 'low PUFA:SFA (P:S) ratio' component and a 'high n-3 LCP' component. There were no differences between tertiles of the 'high n-3 LCP' component and gestational age at delivery (P=0·62), customised birth weight (P=0·38) or incidence of SGA birth (P=0·25), nor were there any associations between the 'low P:S' ratio component and pregnancy outcome. Lower proportions of n-3 LCP in plasma lipids are not associated with greater risk of adverse pregnancy outcomes in UK adolescents.

Plasma Fatty Acid Composition as a Predictor of Arterial Stiffness and Mortality

Aortic stiffness predicts cardiovascular mortality and may be influenced by dietary fat composition. The hypothesis that plasma fat composition influences arterial stiffness and subsequent mortality was tested here in a prospective study. A total of 174 randomly sampled nondiabetic participants aged 45 to 74 years were recruited from local populations, stratified by ethnicity and gender, and followed up for mortality. Aortic pulse wave velocity (PWV), blood pressure, and fatty acid composition of plasma lipids were measured at baseline. PWV was associated with increased cardiovascular mortality and inversely related to the proportions of docosahexaenoic (rho=-0.22; P=0.02) and arachidonic acids (rho=-0.25; P<0.001) in plasma lipids. Principal component analyses identified a cluster characterized by higher proportions of palmitate, palmitoleic and oleic acid and lower proportions of linoleic, dihomo-gamma linolenic, and arachidonic acids. This cluster was positively associated with PWV, central adiposity, smoking, and increased mortality (hazard ratio: 1.13; 95% CI: 1.01 to 1.27). A second cluster, with higher proportions of arachidonic, eicosapentaenoic, and docosahexaenoic and lower proportions of oleic, palmitic, and linoleic acid levels, was associated with lower PWV and systolic blood pressure but also decreased risk of mortality (hazard ratio: 0.57; 95% CI: 0.39 to 0.82), independent of PWV and blood pressure. These data suggest that plasma fatty acid profiles characterized by a higher proportion of long-chain polyunsaturated fatty acids are associated with decreased cardiovascular mortality, independent of the impact of aortic PWV. The results are consistent with an effect of dietary sources of n-3 long-chain polyunsaturates influencing arterial stiffness and mortality.

Fatty acid composition of erythrocyte membrane lipids in healthy subjects from birth to young adulthood

The fatty acid composition of erythrocyte membrane lipids may better reflect the fatty acid status of the organism than the fatty acid composition of plasma lipids. The present study aimed to provide normal values for erythrocyte fatty acid composition in a sizeable group of healthy subjects throughout the paediatric age group. The fatty acid composition of erythrocyte membrane phosphatidylcholine (PC) and phosphatidylethanolamine (PE) lipids was determined by high-resolution capillary gas chromatography in 188 apparently healthy subjects from birth to young adulthood (newborns: n=17, infants: n=97, children: n=38, young adults: n=36). The values of linoleic acid (C18:2n-6) increased steadily between birth and young adulthood (newborns: 6.49 [2.45], infants: 14.51 [4.32], children: 18.10 [3.25], young adults: 19.87 [2.03], PC lipids, shown as median [interquartile range, IQR], p<0.001]. In contrast, the values of arachidonic acid (C20:4n-6) were significantly higher in children than in young adults (PC: 9.48 [6.64] versus 8.00 [1.85], PE: 26.38 [3.98] versus 24.46 [2.44], p<0.05). The values of alpha-linolenic acid (C18:3n-3) decreased significantly between children and young adults (0.14 [0.11] versus 0.08 [0.07], PE lipids, p<0.05). The values of docosahexaenoic acid (C22:6n-3) increased significantly from infancy through childhood up to young adulthood (PE: 4.20 [2.41] and 4.55 [0.97] and 6.66 [1.81], p<0.05 and 0.001, respectively). We found significantly higher total trans isomeric fatty acid values in newborns than in infants (PC: 0.60 [0.27] versus 0.43 [0.19], p<0.05; PE: 0.66 [0.76] versus 0.30 [0.26], p<0.001). From the results, we conclude that: (1) the data obtained in the present study may serve as reference values in the evaluation of the fatty acid status from birth to young adulthood; (2) the significantly higher values of trans fatty acids at birth than at later stages of life may be of concern, because previous studies suggested that trans fatty acids may interfere with essential fatty acid metabolism during the perinatal period.

Hypertriglyceridemia and hypercholesterolemia: Effects of drug treatment on fatty acid composition of plasma lipids and membranes

The effect of atorvastatin, simvastatin and gemfibrozil on fatty acid composition of plasma phospholipids (PL), cholesterol esters (CE), triglycerides (TG) and red cell membrane ghosts (G) has been determined in appropriate sample populations of individuals with hypertriglyceridemia (HTG) or hypercholesterolemia (HCHL). Treatments were appropriate for the condition, gemfibrozil for HTG and a statin for HCHL. Modifications depend on the drug and lipid fraction examined. Both classes of drugs modify fatty acid composition but gemfibrozil modifications are more numerous and dramatic than are the modifications by statins. Gemfibrozil produces major modifications in fatty acid composition, which are both fatty acid and lipid class specific but generally decreases SFA and increases PUFA (mainly n6) and increases the proportion of fatty acids with chain length of 18C or more. Statins tend to increase chain length but have less effect on saturation. Notably, all three drugs increased arachidonic acid (AA) in PL and CE. Statins decreased gamma-linoleic acid (GLA) in PL and CE but gemfibrozil only increased GLA in TG.

Dietary supplementation of obese children with 1000 mg alpha-linolenic acid per day: a placebo-controlled double blind study

Enhanced dietary intake of omega-3 fatty acids may benefit persons with increased cardiovascular risk, among them obese subjects. Incorporation of omega-3 fatty acids into the plasma lipids is a prerequisite to achieve the favorable effects; however, only very few data are available on the dose of omega-3 fatty acid supplementation in children. The aim of our study was to examine the effects of the consumption of a diet supplemented with 1000 mg alpha-linolenic acid daily on plasma lipids in obese children. In this two times six-week-long, placebo-controlled, crossover study, 9 obese children (age: 13.1 [2.5] years, body mass index: 31.2 [6.2] kg/m 2 ), median [IQR]) incorporated into their diet one egg and one meatball (50 g) per day from hens fed diets containing flaxseed oil, i.e. supplementary dietary intake of 1000 mg alpha-linolenic acid per day was provided. The fatty acid composition of plasma lipids was determined by high-resolution gas-liquid chromatography. Tendencies of increase were observed in the alpha-linolenic acid content of plasma lipids in the phospholipid, triacyl-glycerine and sterol-ester fractions after the supplementation with alpha-linolenic acid. In the non-esterified fatty acid fraction, the values of alpha-linolenic acid were significantly higher after the supplementation (0.11 [0.08] versus 0.14 [0.20], % weight/weight, p < 0.05), indicating the beginning of the accumulation of alpha-linolenic acid in plasma lipids. In obese children a six-week-long supplementation of the diet with 1000 mg alpha-linolenic acid per day increased significantly the contribution of omega-3 fatty acids only to the non-esterified fatty acids of plasma lipids, but had no significant effect on the esterified fractions. Increase of the dose of supplementation may be needed to influence omega-3 fatty acid status in obese children.

Competition between 24:5n-3 and ALA for Δ6 desaturase may limit the accumulation of DHA in HepG2 cell membranes

The use of Delta 6 desaturase (D6D) twice in the conversion of alpha-linolenic acid (ALA; 18:3n-3) to docosahexaenoic acid (DHA; 22:6n-3) suggests that this enzyme may play a key regulatory role in the synthesis and accumulation of DHA from ALA. We examined this using an in vitro model of fatty acid metabolism to measure the accumulation of the long-chain metabolites of ALA in HepG2 cell phospholipids. The accumulation of ALA, eicosapentaenoic acid (20:5n-3), docosapentaenoic acid (22:5n-3), and 24:5n-3 in cell phospholipids was linearly related to the concentration of supplemented ALA over the range tested (1.8-72 microM). The accumulation of the post-D6D products of 22:5n-3, 24:6n-3 and DHA, in cell phospholipids was saturated at concentrations of >18 microM ALA. Supplementation of HepG2 cells with preformed DHA revealed that, although the accumulation of DHA in cell phospholipids approached saturation, the level of DHA in cell phospholipids was significantly greater compared with the accumulation of DHA from ALA, indicating that the accumulation of DHA from ALA was not limited by incorporation. The parallel pattern of accumulation of 24:6n-3 and DHA in response to increasing concentrations of ALA suggests that the competition between 24:5n-3 and ALA for D6D may contribute to the limited accumulation of DHA in cell membranes.

Association ofn-3 andn-6 long-chain polyunsaturated fatty acids in plasma lipid classes with inflammatory bowel diseases

In order to establish the biochemical basis for dietary interventions, we investigated the fatty acid composition of plasma lipid classes in patients with inactive inflammatory bowel disease. In this cross-sectional study thirty patients with ulcerative colitis (UC), twenty-one with Crohn disease (CD) and twenty-four controls were investigated (mean age: UC, 40.8 (sd 12.1); CD, 37.6 (sd 11.0); control, 31.5 (sd 8.4) years). Fatty acid composition of plasma lipids was determined by high-resolution capillary GLC. In plasma phospholipids, significantly higher values of eicosapentaenoic (20 : 5n-3), docosapentaenoic (22 : 5n-3) and gamma-linolenic (18 : 3n-6) acids were found in control patients and patients with UC as compared to patients with CD [median % (weight by weight), control v. UC v. CD : 20 : 5n-3, 0.09 (interquartile range (IQR) 0.05) v. 0.14 (IQR 0.10) v. 0.16 (IQR 0.10), P < 0.05; 22 : 5n-3, 0.14 (IQR 0.10) v. 0.27 (IQR 0.16) v. 0.31 (IQR 0.10), P < 0.001; 18 : 3n-6, 0.02 (IQR 0.02) v. 0.03 (IQR 0.02) v. 0.05 (IQR 0.03), P < 0.05]. When compared to the control, values of the principal n-3 and n-6 long-chain PUFA, arachidonic acid (20 : 4n-6) and DHA (22 : 6n-3) were significantly higher in patients with UC but not in patients with CD [median % (w/w), UC v. control: 20 : 4n-6, 8.43 (IQR 3.23) v. 6.92 (IQR 2.96), P < 0.05; 22 : 6n-3, 1.22 (IQR 0.56) v. 0.73 (IQR 0.39), P < 0.05]. As seen there are considerable differences between the long-chain PUFA status of patients suffering from UC or CD. The data obtained in the present study do not support the concept of eicosapentaenoic acid or DHA deficiency in patients with either UC or CD.

Effect of dietary lipids on plasma fatty acid profiles and prostaglandin and leptin production in gilthead seabream ( Sparus aurata)

The aim of this study was to investigate the effects of different levels of substitution of fish oil by vegetable oils rich in oleic, linoleic and linolenic acids on gilthead seabream plasma and leukocyte fatty acid compositions and prostaglandin (PG) and leptin production. Juvenile seabream of 24 g initial body mass were fed four iso-energetic and iso-proteic experimental diets for 281 days. Fatty acid composition of plasma lipids was markedly affected by the inclusion of vegetable oils (VO). ARA (arachidonate), EPA (eicosapentaenoate) and DHA (docosahexaenoate) were preferentially incorporated into polar lipids of plasma, and DHGLA (di-homogammalinoleate) accumulated with increased vegetable oil inclusion. Dietary treatments resulted in alterations of DHGLA/ARA ratios, but not ARA/EPA. ARA-derived PGE 2 production in plasma was not affected by vegetable oils, in agreement with similar eicosanoid precursor ratio (ARA/EPA) in leukocytes total lipids and plasma phospholipids among fish fed with the different dietary treatments. Feeding vegetable oils leads to a decrease in plasma EPA which in turn reduced plasma PGE 3 concentration. Moreover, PGE 3 was the major prostaglandin produced in plasma of fish fed fish oil based diet. Such findings point out the importance of EPA as a precursor of prostaglandins in marine fish, at least for the correct function of the blood cells, and correlates well with the predominant role of this fatty acid in immune regulation in this species. A negative correlation was found between plasma PGE 2 and leptin plasma concentration, suggesting that circulating levels of leptin may act as a metabolic signal modulating PGE 2 release. The present study has shown that increased inclusion of vegetable oils in diet for gilthead seabream may profoundly affect the fatty acid composition of plasma and leukocytes, specially HUFA (highly unsaturated fatty acids), and consequently the production of PGE 3, which can be a major PG in plasma. Alteration in the amount and type of PG produced can be at least partially responsible for the changes in the immune system and health parameters of fish fed diets with high inclusion of VO.

87 Anthropometric Indices Indicative of Obesity are Positively Related to N-6 Long-Chain Polyunsaturated Fatty Acids in Plasma Lipids of Obese Children

Introduction: Controversial data were reported in studies on fatty acid composition of plasma lipids in obese subjects (cf. Decsi et al, Lipids 31: 305–311, 1996 and 35: 1179–1184, 2000 to Phinney et al, Am J Clin Nutr 53: 831–838, 1993). The equivocal data obtained in different studies may be related to differences in anthropometric characteristics of the study populations.Subjects and methods: Obese children (n = 114, age: 13 [3.1] years, body weight (BW): 76.6 [20.7] kg, relative body weight (RBW): 165.8 [22.7] %, body mass index (BMI): 41.3 [4.1] kg/m2, body fat (BF): 38.7 [4.0] %, waist/hip ratio: 0.85 [0.07]), mean [SD]) were investigated. Fatty acid composition of plasma lipid classes was determined by high-resolution capillary gas-liquid chromatography.Results: The contribution of n-6 PUFA to the fatty acid composition of plasma sterol esters were as follows: linoleic acid (C18:2n-6, LA): 53.40 [6.19], dihomo-gamma-linolenic acid (C20:3n-6, DHGLA): 0.86 [0.26], arachidonic acid (C20:4n-6, AA): 8.10 [2.83], ratio of gamma-linolenic acid (C18:3n-6, GLA) plus DHGLA to LA: 0.03 [0.01], data are % weight/weight, median [IQR]. Values of LA showed significant and inverse correlation with RBW. In contrast, values of DHGLA showed significant and positive correlations with RBW and BMI, and AA values exhibited significant and positive correlations with BW, BMI and BF (Table). The product/substrate ratios for the delta-6-desaturase enzyme ([GLA+DHGLA]/LA) were significantly and positively related to RBW and to the waist/hip ratio (Table).Table 1 Spearman rank correlation coefficients between anthropometric characteristics and plasma sterol ester fatty acids in 114 obese children. *P < 0.05; **P < 0.001Full size tableConclusions: 1. In the present study, various anthropometric indices indicative of obesity were significantly and positively related to n-6 long-chain polyunsaturated fatty acids in plasma lipids of obese children. 2. The product/substrates ratios for the delta-6 desaturase enzyme indicated enhanced conversion rate with more pronounced obesity. 3. Extent of obesity should be taken into account in studies on fatty acid metabolism in obese subjects.

45 The -866A/A but not the -866G/A Genotype of Uncoupling Protein 2 Gene is Associated with Reduced Dihomo-Gamma-Linolenic Acid Values in Obese Children

Introduction: Previously we found significantly higher values of the n-6 long-chain polyunsaturated fatty acids, gamma-linolenic acid (C18:3n-6), dihomo-gamma-linolenic acid (C20:3n-6) and arachidonic acid (C20:4n-6) in plasma lipids in obese children than in nonobese controls (Decsi et al, Lipids 31: 305–311, 1996). Recently, an association between obesity, lipid metabolism disorders and the G-allele of the -866G/A polymorphism in the promoter region of uncoupling protein 2 gene (UCP2) was reported (Le Fur et al, Diabetes 53: 235–239, 2004). Here we report data on the association of the -866G/A polymorphism of UCP2 to the fatty acid composition of plasma lipids in obese children. Subjects and methods: Obese children (n = 80, age: 13 [2.7] years, body mass index: 41.7 [4.4] kg/m2, body fat: 39.1 [4.2] %, mean [SD]) were investigated. Genotyping was performed by polymerase chain reaction with subsequent restriction fragment length polymorphism analysis. Fatty acids were determined by high-resolution capillary gas-liquid chromatography. Results: The frequencies of the different genotypes were as follows: -866G/G: 42.5%, -866G/A: 42.5%, -866A/A: 15%. Anthropometric characteristics did not differ among the 3 groups. Values of eicosadienoic acid (C20:2n-6) in phospholipids and values of C20:3n-6 in sterol esters were significantly lower in children with the -866A/A genotype than in the other two groups (Table). Values of C20:3n-6 were also significantly lower in children with the -866A/A than in those with the -866G/A genotype in plasma phospholipids (Table). Table: Fatty acid composition of plasma phospholipids and sterol esters in 80 obese children stratified according to genotype of the UCP2. Data are median [IQR], a, b = P < 0.05 Conclusion: In this study, we found significantly lower values of dihomo-gamma-linolenic acid, an important eicosanoid precursor, in plasma lipids of -866A/A homozygote compared with -866 G/A heterozygote and -866G/G normal obese children.

Fatty acid composition of plasma lipids and erythrocytes in adult goats in positive energy balance fed diets containing either olive or corn oil

The hypothesis tested was, that in ruminating goats on positive energy balance the dietary intake of polyunsaturated fatty acids would be reflected in the fatty acid composition of erythrocytes. Eight goats were fed a diet rich in olive oil, supplying 34% the energy requirement for maintenance (NE l). Four animals were given diets containing either olive or corn oil at an energy level of 1.5 times the requirement for maintenance. Each feeding period lasted 21 days. On the last day of each period, plasma and erythrocytes were collected. Feeding of the diet containing corn oil, which is rich in linoleic acid, resulted in a significant increase in the level of linoleic acid in both plasma lipids and erythrocytes. Likewise, feeding of the diet containing olive oil, while the goats were in positive energy balance, produced higher levels of oleic acid in plasma lipids and erythrocytes. The fatty acid composition of plasma lipids was influenced more strongly by dietary unsaturated fatty acids than that of erythrocytes. The concentrations of plasma lipids, including total cholesterol, did not respond to the type of fat during the experimental periods. When the goats were in negative energy balance, they had significantly higher plasma levels of non-esterified fatty acids. The present study demonstrates that dietary unsaturated fatty acids are incorporated into plasma total lipids and erythrocytes, suggesting a partial escape of dietary unsaturated fatty acids from ruminal biohydrogenation. The escape from hydrogenation may ensure the provision to the goat tissues of essential, polyunsaturated fatty acids. It further implies that the composition of ruminant milk and meat can be influenced by the intake of polyunsaturated fatty acids.