Phospholipid FA Research Articles

Dietary fish oil dose‐response effects on ileal phospholipid fatty acids and contractility

We have reported that dietary fish oil (FO) leads to the incorporation of long-chain n-3 PUFA into the gut tissue of small animal models, affecting contractility, particularly of rat ileum. This study examined the FO dose response for the incorporation of n-3 PUFA into ileal tissue and how this correlated with in vitro contractility. Groups of ten to twelve 13-wk-old Wistar-Kyoto rats were fed 0, 1, 2.5, and 5% FO-supplemented diets balanced with sunflower seed oil for 4 wk, after which ileal total phospholipid FA were determined and in vitro contractility assessed. For the total phospholipid fraction, increasing the dietary FO levels led to a significant increase first evident at 1% FO, with a stepwise, nonsaturating six-fold increase in n-3 PUFA as EPA (20:5n-3), DPA (docosapentaenoic acid, 22:5n-3), and DHA, but mainly as DHA (22:6n-3), replacing the n-6 PUFA linoleic acid (18:2n-6) and arachidonic acid (20:4n-6) over the dosage range. There was no difference in KCl-induced depolarization-driven contractility. However, a significant increase in receptor-dependent maximal contractility occurred at 1% FO for carbachol and at 2.5% FO for prostaglandin E2, with a concomitant increase in sensitivity for prostaglandin E2 at 2.5 and 5% FO. These results demonstrate that significant increases in ileal membrane n-3 PUFA occurred at relatively low doses of dietary FO, with differential receptor-dependent increases in contractility observed for muscarinic and prostanoid agonists.

Dietary α‐linolenic acid increases brain but not heart and liver docosahexaenoic acid levels

Fish oil-enriched diets increase n-3 FA in tissue phospholipids; however, a similar effect by plant-derived n-3 FA is poorly defined. To address this question, we determined mass changes in phospholipid FA, individual phospholipid classes, and cholesterol in the liver, heart, and brain of rats fed diets enriched in flax oil (rich in 18:3n-3), fish oil (rich in 22:6n-3 and 20:5n-3), or safflower oil (rich in 18:2n-6) for 8 wk. In the heart and liver phospholipids, 22:6n-3 levels increased only in the fish oil group, although rats fed flax oil accumulated 20:5n-3 and 22:5n-3. However, in the brain, the flax and fish oil diets increased the phospholipid 22:6n-3 mass. In all tissues, these diets decreased the 20:4n-6 mass, although the effect was more marked in the fish oil than in the flax oil group. Although these data do not provide direct evidence for 18:3n-3 elongation and desaturation by the brain, they demonstrate that 18:3n-3-enriched diets reduced tissue 20:4n-6 levels and increased cellular n-3 levels in a tissue-dependent manner. We hypothesize, based on the lack of increased 22:6n-3 but increased 18:3n-3 in the liver and heart, that the flax oil diet increased circulating 18:3n-3, thereby presenting tissue with this EFA for further elongation and desaturation.

Dietary nucleotides do not alter erythrocyte long‐chain polyunsaturated fatty acids in formula‐fed term infants

There have been conflicting reports regarding the effectiveness of dietary nucleotides (NT) to regulate tissue desaturases and hence stimulate accumulation of both n-6 and n-3 long-chain polyunsaturated fatty acids (LCPUFA). The aim of this study was to examine the effect of NT-supplemented cow's milk-based formula on erythrocyte phospholipid FA status in a large randomized controlled trial involving a well-nourished infant population born at term. Formula-fed infants were allocated to control formula with an innate level of NT at 10 mg/L (n = 102), or formula fortified with NT at 34 mg/L (n = 98). A parallel group of breastfed infants was included as a reference. Peripheral blood samples were collected by venipuncture at 7 mon of age and erythrocyte phospholipid FA determined by capillary GC. Erythrocyte LCPUFA levels did not differ between the NT-supplemented and control formula groups and were reduced in both groups compared with breastfed infants. We conclude that there is no induction of LCPUFA accumulation in erythrocyte phospholipids of term, formula-fed infants following 7 mon of NT supplementation.

Dynamics of blood chylomicron fatty acids in a marine carnivore: implications for lipid metabolism and quantitative estimation of predator diets

Blubber fatty acid(s) (FA) signatures can provide accurate estimates of predator diets using quantitative FA signature analysis, provided that aspects of predator FA metabolism are taken into account. Because the intestinal absorption of dietary FA and their incorporation into chylomicrons (the primary transport lipoproteins for dietary FA in the blood) may influence the relationship between FA composition in the diet and adipose tissue, we investigated the metabolism of individual FA at these early stages of assimilation. We also investigated the capacity of chylomicron signatures to provide quantitative estimates of prey composition of an experimental meal. Six captive juvenile grey seals (Halichoerus grypus) were fed either 2.3 kg (n = 3) or 4.6 kg (n = 3) of Atlantic herring (Clupea harengus). Although chylomicron FA signatures resembled diet signatures at all samplings, absolute differences were smallest at 3-h post-feeding, when chylomicrons were likely largest and had the greatest ratio of triacylglycerol to phospholipid FA. Specific FA that differed significantly between diet and chylomicron signatures reflected either input from endogenous sources or loss through peroxisomal beta-oxidation. When these aspects of metabolism were accounted for, the quantitative predictions of diet composition generated using chylomicron signatures were extremely accurate, even when tested against 28 other prey items.

PC60 SPANISH PREGNANT WOMEN???S PLASMA PHOSPHOLIPIDS LC-PUFAS CONCENTRATIONS & ITS INFLUENCE ON THEIR NEWBORNS

Introduction: The foetal accretion of LC-PUFAs depend on mother’s stores, dietary intake and endogenous synthesis of LC-PUFAs. Recently, it has been demonstrated that placental tissue has a preferential metabolic pathway to transfer DHA from the mother to the foetus, in comparison with linoleic, oleic or palmitic acids. The aim of this study is to analyse if different nutritional supplements during pregnancy enhance the neonate nutritional status of DHA. Methods: A total of 153 Spanish healthy pregnant women participants in the NUHEAL study; aged between 18 and 40 years, were recruited at the 20±1 wks of gestation. Following a double blind & random design, were subdivided into 4 groups, depending on the supplement received until delivery (DHA: 0.5 g/day; 5-MTHF: 0.4 mg/day; both or placebo). Plasma phospholipid FA were measured by gas chromatography. ANOVA, General lineal model with repeated measures & correlation study were performed using SPSS Versions 11.5. Results: The groups 1 & 4 showed higher concentrations of plasma phospholipid DHA & lower ratios n-6/n3 & AA/DHA, in the 30th & at delivery than groups 2 and 3 (a, b). The groups 1 and 4 showed an increment of DHA between 20th and 30th, but not between 30th wks & delivery. The groups 2 and 3 didn’t show any change from 20th wks until delivery(*,#). No changes in plasma phospholipid AA were observed in all groups, even in the neonates. Mother-neonate significant correlations were established (DHA: r: 0.30, p=0.0028; AA/DHA: r: −0.43, p<0.00001). The only n-3 PUFA found in umbilical cord was DHA.Table 1Conclusion: There is significant differences between the groups studied, and depending on the supplement received there is an increase of plasma phospholipid DHA in mother & infant, without modifications in AA levels. n-6/n-3 & AA/DHA ratios were lower in the groups 1 and 4. The reason of these results will be explained after the study finish the present unblended situation. The preferential placental mechanism for transferring DHA from mother to the foetus is indirectly suggested.

Blood phospholipid fatty acid analysis of adults with and without attention deficit/hyperactivity disorder.

Several psychiatric disorders, including juvenile Attention Deficit/Hyperactivity Disorder (ADHD), have been associated with abnormalities of certain long-chain PUFA (LCPUFA). Despite this reported association, the FA levels of patients with the adult form of ADHD have not previously been evaluated. In this study we measured the total blood phospholipid FA concentrations in 35 control subjects and 37 adults with ADHD symptoms to determine whether adults with ADHD symptoms would show abnormalities of FA relative to control subjects. In the serum phospholipids, adults with ADHD symptoms had significantly lower levels of total saturated, total polyunsaturated, and total omega-6 (n-6) FA, as well as the omega-3 (n-3) LCPUFA DHA (22:6n-3), and significantly higher levels of total monounsaturated FA and the n-3 LCPUFA docosapentaenoic acid (22:5n-3). In the erythrocyte membrane phospholipids, adults with ADHD symptoms had significantly lower levels of total PUFA, total n-3 FA, and DHA, and significantly higher levels of total saturated FA. Neither serum nor erythrocyte membrane phospholipid DHA was related to ADHD symptom severity (as assessed by the Amen questionnaire) in ADHD subjects. Although the exact cause of these variations is unknown, both environmental and genetic factors may be involved.

Fatty acids of lipid fractions in extracellular polymeric substances of activated sludge flocs.

Phospholipid (PL), glycolipid (GL), and neutral lipid (NL) FA, and the lipopolysaccharide 2- and 3-hydroxy (LPS 2-OH and 3-OH) FA of activated sludges and extracted extracellular polymeric substances (EPS) were determined on samples collected from two wastewater treatment plants. EPS extracted from sludges by means of sonication and cation exchange contained proteins (43.4%), humic-like substances (11.5%), nucleic acids (10.9%), carbohydrates (9.9%), and lipid-bound FA (1.8%). The lipids associated with EPS were composed of GL, PL, NL, and LPS acids in proportions of 61, 21, 16, and 2%, respectively. The profiles of lipid-bound FA in activated sludges and EPS were similar (around 85 separate FA were identified). The FA signatures observed can be attributed to the likely presence of yeasts, fungi, sulfate-reducing bacteria, gram-positive and gram-negative bacteria, and, in lesser quantities, mycobacteria. Comparison of data from the dates of sampling (January and September) showed that there were more unsaturated PLFA in the EPS extracted from the activated sludges sampled in January. This observation could be partly related to microorganism adaptation to temperature variations. The comparison between two wastewater treatment plants showed that the FA profiles were similar, although differences in microbial community structure were also seen. Most of the FA in sludges had an even number of carbons.

Phospholipid FA of piezophilic bacteria from the deep sea.

Phospholipid FA (PLFA) profiles were determined on four piezophilic bacteria from the deep sea: Moritella japonica DSK1, Shewanella violacea DSS12, S. benthica DB6705, and S. benthica DB21MT-2. The total concentrations of PLFA were higher in strains grown at low pressure (DSK1, 10 MPa, 27.0 mg/g dry wt cells; DSS12, 50 MPa, 24.0 mg/g), and lower in strains grown at high pressure (DB6705, 85 MPa, 1.9 mg/g; DB21MT-2, 100 MPa, 3.0 mg/g). The piezophilic bacteria were characterized by a high abundance of unsaturated FA (62-73% of total FA). In particular, PUFA were detected in all piezophiles examined. Moritella japonica DSK1 produced 22:6n-3 (DHA), whereas the three Shewanella strains produced 20:5n-3 (EPA) with trace amounts of DHA. The detection of low levels of the medium-chain-length PUFA 18:2n-6 and 18:3 (DSK1) and 20:2 (DB6705 and DB21MT-2) suggests that the biosynthesis of EPA and DHA may be regulated by the formation and desaturation of di- and tri-unsaturated FA.

Lipids and FA analysis of canine prostate tissue

It is widely reported that an association exists between dietary fat intake and the incidence of prostate cancer in humans. To study this association, there is a need for an animal model where prostate carcinogenesis occurs spontaneously. The canine prostate is considered a suitable experimental model for prostate cancer in humans since it is morphologically similar to the human prostate and both humans and dogs have a predisposition to benign and malignant prostate disease. In this study, the FA and lipids profiles of the normal canine prostate tissue from nine dogs were examined. The total lipid content of the canine prostate tissue was 1.7 +/- 0.5% (wet weight). The lipid composition analysis using TLC-FID showed that the two major lipid classes were phospholipids and TAG. Total FA, phospholipid, and TAG FA analysis showed that the major FA were palmitic acid (16:0), stearic acid (18:0), oleic acid (18:1), linoleic acid (18:2n-6), and arachidonic acid (20:4n-6). The n-3 FA were present at <3% of total FA and included alpha-linolenic acid (18:3n-3) (in total and TAG tissue FA), EPA (20:5n-3) (not in TAG), and DHA (22:6n-3) (not in TAG). The n-3/n-6 ratio was 1:11, 1:13, and 1:8 in total, phospholipid, and TAG FA, respectively. This study shows the canine prostate has a low level of n-3 FA and a low n-3/n-6 ratio. This is perhaps due to low n-3 content of the diet of the dogs. FA analysis of dogfoods available in Australia showed that the n-3 content in both supermarket and premium brand dogfoods was <3% (wet weight), and the n-3/n-6 ratio was low.

Liver desaturase activities and FA composition in monkeys. Effect of a low-protein diet.

The aim of the present study was to measure delta9-, delta6-, and delta5-desaturase activities in liver microsomes, as well as phospholipid FA composition of liver and erythrocytes in monkeys fed a control or low-protein diet during the postweaning period. Ten Saimiri sciureus boliviensis (Cebidae) of both sexes were employed; at 12 mon of age they were separated into two groups fed ad libitum on a control or a low-protein diet for 24 mon. Saimiri sciureus had active delta9, delta6, and delta5 liver desaturase enzymes, and these activities were influenced by the diet. A low-protein diet produced a significant reduction in delta5-desaturation capacity, an increase in delta9-desaturase activity, and no change in delta6-desaturase activity (P < 0.05). These changes, evoked by protein deprivation, were reflected in the liver phospholipid FA composition. Increases in the proportion of saturated FA and in monounsaturated oleic acid (18:1n-9) and a decrease in the proportion of PUFA of the n-6 and n-3 series were produced in the animals fed a low-protein diet (P < 0.0001).

A biomarker of n-3 compliance in patients taking fish oil for rheumatoid arthritis.

Dietary fish oil supplements have been shown to have benefits in rheumatoid arthritis (RA), other inflammatory diseases, and in cardiovascular disease. As with any medical advice, variability will exist with regard to adherence and consequent biochemical or pharmacophysiologic effects. The aim was to explore the utility of plasma phospholipid EPA as a measure of n-3 PUFA intake and response to standardized therapeutic advice given in an outpatient or office practice setting, to increase dietary n-3 PUFA, including a fish oil supplement. Patients with early RA were given verbal and written advice to alter their dietary n-3 PUFA intake, including ingestion of 20 mL of bottled fish oil on juice daily. The advice included instructions to increase n-3 PUFA and to avoid foods rich in n-6 PUFA. Every 3 mon, blood samples were obtained for analysis of plasma phospholipid FA. Plasma phospholipid EPA was used as the primary index of n-3 PUFA intake. A diverse response was seen, with about one-third of patients achieving a substantial elevation of plasma phospholipid EPA over the 12-mon study period. A third had little change, with the remainder achieving intermediate levels. Data obtained longitudinally from individual patients indicated that substantial elevations of EPA (> 5% total plasma phospholipid FA) could be maintained for more than 3 yr. Plasma phospholipid EPA is a convenient measure of adherence to advice to take a dietary n-3 PUFA-rich fish oil supplement This measure may prove a useful adjunct to intention to treat analyses in determining the effect of dietary fish oil supplements on long-term outcomes in arthritis and other chronic inflammatory diseases. It may also provide a guide to the effectiveness of therapeutic and preventive messages designed to increase n-3 PUFA intake.

Phospholipid class and FA compositions of modified soybeans processed with two extraction methods

AbstractSoybean lecithin is used as an emulsifier in food, cosmetic, and pharmaceutical industries. The proportion of individual phospholipids (PL) and their FA composition may affect the functional properties of lecithin. In this research, lecithins recovered from four modified soybeans and one commodity soybean, which were processed by extrusion‐expelling and conventional solvent extraction, were analyzed for proportion of PL class and FA composition. HPLC with an ELSD analysis demonstrated that the percentage of PC in extrusion‐expelled lecithin was higher than in solvent‐extracted lecithin, whereas the PE content was lower. GC analysis showed that FA compositions of the PL varied with soybean type. The oil extraction method did not significantly affect FA composition. Critical micelle concentration tested with a tensiometer showed differences among the lecithins.

Total synthesis of 2-methoxy-14-methylpentadecanoic acid and the novel 2-methoxy-14-methylhexadecanoic acid identified in the sponge Agelas dispar.

The phospholipid FA composition of the Caribbean sponge Agelas dispar was revisited and 40 different FA were identified. Among these a novel 2-methoxylated FA, namely, the anteiso methyl-branched 2-methoxy-14-methylhexadecanoic acid, was identified together with the recently discovered iso methyl-branched 2-methoxy-14-methylpentadecanoic acid and the normal-chain 2-methoxytetradecanoic acid. The structures of the iso and anteiso methyl-branched 2-methoxylated FA were confirmed by total syntheses, which were accomplished in seven steps and in 45-48% overall yields. Other phospholipid FA identified in A. dispar include the unusual methyl-branched 10,13-dimethyltetradecanoic acid, 3,7,11,15-tetramethylhexadecanoic (phytanic) acid, and the 11-methyloctadecanoic acid. In addition, the delta5,9 FA (5Z,9Z)-15-methyl-5,9-hexadecadienoic acid and (5Z,9Z)-5,9-octadecadienoic acid were characterized. These findings establish alternative FA biosynthetic possibilities for these marine organisms.

Relationship between platelet phospholipid FA and mean platelet volume in healthy men.

Increased mean platelet volume (MPV) has been suggested as an independent risk factor for acute myocardial infarction and the increased reactivity of large platelets. The aim of this study was to investigate the correlation between platelet phospholipid (PL) PUFA composition and MPV in 139 free-living healthy men ages 20-55 yr (vegans, n = 18; ovolacto vegetarians, n = 43; moderate meat-eaters, n = 60; and high meateaters, n = 18). Each subject completed a semiquantitative Food Frequency Questionnaire and gave a blood sample. Platelet PL FA composition and MPV were determined by standard methods. MPV was significantly greater in the vegans than in the ovolacto vegetarian, moderate, or high meat-eater groups (P < 0.01). Both vegan and ovolacto vegetarian groups had significantly higher platelet PL 18:2n-6 and 22:4n-6, and lower 20:5n-3 and 22:6n-3 compared with the moderate and high meat-eater groups. The vegans demonstrated a significant reduction in 20:4n-6 and 22:5n-3 compared with the ovolacto vegetarian, high meat-eater, and moderate meat-eater groups. Bivariate analysis results showed that MPV was significantly positively correlated with platelet PL 18:2n-6 (P = 0.048) and negatively correlated with 20:3n-6 (P = 0.02), 20:5n-3 (P = 0.005), and 22:5n-3 (P< 0.0001), respectively. In a multiple linear regression analysis, after controlling for potential confounding factors such as dietary group, age, exercise, body mass index, and dietary polyunsaturated and saturated fat, cholesterol, carbohydrate, and fiber intake, the MPV was still strongly negatively correlated with platelet PL 20:3n-6 (P = 0.003) and 22:5n-3 (P = 0.001). The present data suggest that 22:5n-3 and 20:3n-6 may play a role in the structural function of the platelet membrane.

Retinal sensitivity loss in third-generation n-3 PUFA-deficient rats.

A previous study conducted in guinea pigs suggested that ingestion of diets high in EPA and DHA may result in suboptimal retinal function. The aim of the present study was to evaluate retinal function in pigmented (Long-Evans) rats, raised to a third generation on diets that were either deficient in n-3 PUFA or adequate (with the addition of DHA). Electroretinographic assessment employed full-field white flash stimulation. Photoreceptor responses were evaluated in terms of peak amplitudes and implicit times (a-wave, b-wave), intensity-response functions (Naka-Rushton), and the parameters of a model of transduction (P3). Retinal phospholipid FA composition was measured by capillary GLC. DHA levels were reduced by 55% in n-3-deficient animals compared with the n-3-adequate group, whereas the levels of docosapentaenoic acid n-6 were 44 times higher in n-3-deficient animals. The level of arachidonic acid was marginally higher (12.8%) in n-6-adequate animals. The n-3-deficient animals exhibited significantly reduced retinal sensitivity (sigma and S values were both affected by 0.29 log units) and increased b-wave implicit times compared with those fed the n-3-adequate diet. These data suggest that n-3 PUFA are required for development of retinal sensitivity, more so than other indices of retinal function assessed by current methods, such as maximal response amplitude. However, the benefit for retinal function of adding preformed DHA to diets already replete in n-3 PUFA remains unclear.

Localisation of constitutive nitric oxide synthase (cNOS) and vascular endothelial growth factor (VEGF) in the uteroplacental bed from normotensive and pre-eclamptic pregnancies

Little is known about the mechanisms underlying the preferential transport of long chain polyunsaturated fatty acids (LCPUFA) to the fetus by the syncytiotrophoblast and the role of cytotrophoblasts in placental lipid metabolism and transport. We studied primary human trophoblast (PHT) cells cultured for 90 h to determine the fatty acid and lipid composition of cytotrophoblast (18 h culture) and syncytiotrophoblast (90 h culture) cells. In cultured PHT total lipid fatty acids were significantly (P < 0.05) reduced at 90 h compared to 18 h in culture including lower levels of palmitic acid (PA, 16:0, −37%), palmitoleic acid (POA, 16:1n-7, −30%), oleic acid (OA, 18:1n-9, −31%), LCPUFA arachidonic acid (AA, 20:4n-6, −28%) and α-linolenic acid (ALA, 18:3n-3, −55%). In major lipid classes, OA and most of the n-3 and n-6 LCPUFA were markedly lower at 90 h in TG (−57 to −76%; p < 0.05). In the cellular NEFA, n-6 LCPUFA, dihomo-γ-linolenic acid (DGLA, 20:3n-6) and AA were both reduced by −51% and DHA was −55% lower (p < 0.05) at 90 h. In contrast, phospholipid FA content did not change between cytotrophoblasts and syncytiotrophoblast except for OA, which decreased by −62% (p < 0.05). Decreasing PHT TG and NEFA lipid content at 90 h in culture is likely due to processes related to differentiation such as alterations in lipase activity that occur as cytotrophoblast cells differentiate. We speculate that syncytiotrophoblast prioritizes PL containing AA and DHA for transfer to the fetus by mobilizing FA from storage lipids.

Modification of lipid-related atherosclerosis risk factors by ω3 fatty acid ethyl esters in hypertriglyceridemic patients

The efficacy of ω3 fatty acid ethyl esters was evaluated in 10 mildly hypertriglyceridemic patients in this randomized, placebo-controlled, double-blind, crossover trial. Patients were given capsules (1 per 10 kg body weight) containing 640 mg/g of ω3 fatty acids or an olive oil placebo for two 4-week treatment periods separated by a 1-week washout phase. Plasma lipids, lipoproteins, and apolipoproteins: phospholipid FA composition; the susceptibility to oxidation of the apolipoprotein B-100 containing lipoproteins; and bleeding times were determined at the end of each period. Plasma triglyceride levels were reduced by 37% ( P < 0.001), whereas low density lipoprotein cholesterol and the cholesterol content of subfraction 2 of high density lipoproteins increased by 23 and 56%, respectively (both P < 0.02). Changes in plasma lipid parameters and in phospholipid FA patterns occurred rapidly, usually stabilizing within 1 week, and returned to baseline levels within 10 days after stopping supplementation with ω3 fatty acids. Bleeding times were not changed. However, the susceptibility of lipoproteins to oxidation was increased during the ω3 fatty acid period. We conclude that ω3 fatty acid ethyl esters are effective hypotriglyceridemic agents, and that they impact lipoprotein metabolism very quickly. How they may alter the atherogenic process is not clear from this study because some risk factors worsened and other improved.