Fatty Acid Composition Of Total Phospholipids Research Articles

Correction to: Testing the dogma that total phospholipid fatty acid composition of blood plays a role in kidney stone pathogenesis, using a high-low risk human model: results from a pilot study.

The authors would like to add the following paragraph in the acknowledgement section of the original version of the paper.

Testing the dogma that total phospholipid fatty acid composition of blood plays a role in kidney stone pathogenesis, using a high-low risk human model: results from a pilot study.

Previous studies have suggested that ω-3 and ω-6 polyunsaturated fatty acid (PUFA) composition in plasma and red blood cell (RBC) total phospholipids plays a role in urolithiasis. Our aim was to test the robustness of this dogma by retrospectively comparing baseline profiles of these parameters in subjects from high- and low-stone-risk groups. The documented difference in stone occurrence in white (relatively common) (W) and black (rare) (B) subjects prompted us to select these groups as the high-low risk model for the study. Blood and urine samples were obtained from ten subjects in each group and were analysed for PUFAs and stone risk factors, respectively. Concentrations of linoleic acid (LA), eicosadienoic acid (EDA) and arachidonic acid (AA) in plasma and or/RBC total phospholipids were significantly higher in B. Differences in other PUFA profiles were also observed. There was no inter-group difference in AA/LA ratios. Urinary oxalate was significantly higher while urinary phosphate was significantly lower in B. We speculate that elevated AA in B might arise because of a possibly enhanced elongation of LA to EDA, as well as an enhanced ∆-8-desaturation of EDA to dihomo-gamma-linolenic acid (DGLA), which is the immediate precursor of AA. Alternatively, we speculate that the ∆-5-desaturation step of DGLA to AA might be more highly activated in this group. Irrespective of the mechanism, our observed inter-group differences in phospholipid PUFA composition are in conflict with previously published dogma which relates PUFA characteristics to high- and low-stone risk.

N–3 Long-chain PUFAs reduce respiratory morbidity caused by iron supplementation in iron-deficient South African schoolchildren: a randomized, double-blind, placebo-controlled intervention

Although iron supplementation in malaria-free areas mostly reduces infectious morbidity, it can sometimes increase morbidity from infections as a result of the dependence of pathogenic microorganisms on iron. Supplementation with n-3 (ω-3) long-chain polyunsaturated fatty acids (LCPUFAs) improved morbidity in several human studies. However, information on the combined effect of iron and n-3 LCPUFA supplementation on infectious morbidity is limited. We determined whether n-3 LCPUFAs and iron supplementation, alone or in combination, affected absenteeism and illness in iron-deficient schoolchildren with low fish intake. A total of 321 South African children (aged 6-11 y) with iron deficiency (ID) were randomly divided into 4 groups to receive 1) iron plus placebo, 2) a mixture of docosahexaenoic acid and eicosapentaenoic acid (DHA/EPA) plus placebo, 3) iron plus DHA/EPA, or 4) placebo plus placebo as oral supplements 4 times/wk for 8.5 mo. Morbidity was recorded, and iron-status indexes were measured. The total phospholipid fatty acid composition of peripheral blood mononuclear cell membranes was analyzed in a subsample (n = 130). Iron supplementation increased the number of days with illness when all symptoms were considered (B: 0.87; 95% CI: 0.71, 1.03) as well as illness that was specifically caused by respiratory symptoms (B: 1.45; 95% CI: 1.21, 1.70), whereas DHA/EPA reduced the number of days with illness at school (B: -0.96; 95% CI: -1.33, -0.59). The increases caused by iron were reduced to the levels seen in the placebo plus placebo group when iron was provided in combination with DHA/EPA as indicated by significant iron × DHA/EPA interactions (both P < 0.001). Iron supplementation increased morbidity (mostly respiratory) in iron-deficient South African schoolchildren with low DHA/EPA intake, but when iron was given in combination with DHA/EPA, this effect was prevented.

Selective localization of phosphatidylcholine-derived signaling in detergent-resistant membranes from synaptic endings

Detergent-resistant membranes (DRMs) are a class of specialized microdomains that compartmentalize several signal transduction processes. In this work, DRMs were isolated from cerebral cortex synaptic endings (Syn) on the basis of their relative insolubility in cold Triton X-100 (1%). The lipid composition and marker protein content were analyzed in DRMs obtained from adult and aged animals. Both DRM preparations were enriched in Caveolin, Flotillin-1 and c-Src and also presented significantly higher sphingomyelin (SM) and cholesterol content than purified Syn. Total phospholipid-fatty acid composition presented an increase in 16:0 (35%), and a decrease in 20:4n-6 (67%) and 22:6n-3 (68%) content in DRM from adults when compared to entire synaptic endings. A more dramatic decrease was observed in the 20:4n-6 and 22:6n-3 content in DRMs from aged animals (80%) with respect to the results found in adults. The coexistence of phosphatidylcholine-specific-phospholipase C (PC-PLC) and phospholipase D (PLD) in Syn was previously reported. The presence of these signaling pathways was also investigated in DRMs isolated from adult and aged rats. Both PC-PLC and PLD pathways generate the lipid messenger diacylglycerol (DAG) by catalyzing PC hydrolysis. PC-PLC and PLD1 localization were increased in the DRM fraction. The increase in DAG generation (60%) in the presence of ethanol, confirmed that PC-PLC was also activated when compartmentalized in DRMs. Conversely, PLD2 was excluded from the DRM fraction. Our results show an age-related differential fatty acid composition and a selective localization of PC-derived signaling in synaptic DRMs obtained from adult and aged rats.

Flaxseed oil and fish-oil capsule consumption alters human red blood cell n–3 fatty acid composition: a multiple-dosing trial comparing 2 sources of n–3 fatty acid

BackgroundAn increase in plasma n–3 fatty acid content, particularly eicosapentaenoic acid (20:5n–3; EPA) and docosahexaenoic acid (22:6n–3; DHA), is observed after consumption of fish oil–enriched supplements. Because α-linolenic acid (18:3n–3; ALA) is the direct precursor of EPA and DHA, ALA-enriched supplements such as flax may have a similar effect, although this hypothesis has been challenged because of reported low conversion of ALA into DHA. ObjectiveTo address this question, we designed a clinical trial in which flax oil, fish-oil, and sunflower oil (placebo group) capsules were given to firefighters (n = 62), a group traditionally exposed to cardiovascular disease risk factors. DesignFirefighters were randomly divided into 6 experimental groups receiving 1.2, 2.4, or 3.6 g flax oil/d; 0.6 or 1.2 g fish oil/d; or 1 g sunflower oil/d for 12 wk. Blood was drawn every 2 wk, and the total phospholipid fatty acid composition of red blood cells was determined. ResultsAs expected, fish oil produced a rapid increase in erythrocyte DHA and total n–3 fatty acids. The consumption of either 2.4 or 3.6 g flax oil/d (in capsules) was sufficient to significantly increase erythrocyte total phospholipid ALA, EPA, and docosapentaenoic acid (22:5n–3) fatty acid content. There were no differences among groups in plasma inflammatory markers or lipid profile. ConclusionsThe consumption of ALA-enriched supplements for 12 wk was sufficient to elevate erythrocyte EPA and docosapentaeoic acid content, which shows the effectiveness of ALA conversion and accretion into erythrocytes. The amounts of ALA required to obtain these effects are amounts that are easily achieved in the general population by dietary modification.

Maternal parity and diet (n-3) polyunsaturated fatty acid concentration influence accretion of brain phospholipid docosahexaenoic acid in developing rats.

The long-chain PUFA, docosahexaenoic acid [22:6(n-3), DHA], a major component of neuronal membrane phospholipids, accumulates in brain during late prenatal and early neonatal development and is essential for optimal attentional and cognitive function. Because all nutrition is supplied to the developing fetus/neonate by the mother and maternal DHA status is affected by parity, this study examined the effects of maternal diet and parity on DHA accretion in the developing brain. Whole brain total phospholipid fatty acid composition was determined by TLC and GC in weanling male Long-Evans rats (n = 5) from the 1st, 2nd, 3rd, or 4th litters of dams fed diets containing alpha-linolenic acid (ALA), containing ALA and preformed DHA (ALA + DHA), or lacking ALA (low-ALA). First-litter low-ALA offspring exhibited a decrease in phospholipid fatty acid DHA content to 68% of 1st-litter ALA pups. DHA in 2nd-litter low-ALA pups was further decreased to 55% of 1st-litter ALA pups, but further decreases were not observed in subsequent litters. DHA levels increased 15-20% in 2nd to 4th-litter ALA + DHA pups and 11% in 4th-litter ALA pups compared with 1st-litter ALA pups. These findings demonstrate that maternal diet and parity interact to affect offspring brain DHA status and suggest that maternal multiparity may place offspring at greater risk of decreased accretion of brain DHA if the maternal diet contains insufficient (n-3) PUFA.

Hypothyroid state and membrane fatty acid composition influence cardiac mitochondrial pyruvate oxidation

Pyruvate oxidation was measured in cardiac mitochondria from euthyroid and hypothyroid rats fed diets enriched with either to ω − 6 or ω − 3 fatty acids. Both State 4 and State 3 rates of pyruvate-dependent respiration were markedly reduced in hypothyroid mitochondria, regardless of diet consumed, compared to euthyroid controls. Respiratory control ratios and ADP/O ratios were the same under all treatments. While there was no significant effect of diet on respiration in euthyroid mitochondria, pyruvate oxidation was 28% higher in hypothyroid mitochondria from animals fed the ω − 3 diet compared to those fed the ω − 6 diet. Depressed respiration in the hypothyroid state was correlated with 18% more phosphatidylcholine in the inner mitochondrial membrane whereas phosphatidylethanolamine was 17% lower and cardiolipin 32% lower compared to controls. The total phospholipid fatty acid composition was not affected by the hypothyroid state. However, enhanced respiration in hypothyroid animals fed the ω − 3 diet was associated with a 3-fold increase in monounsaturated fatty acids in the cardiolipin fraction, and a 12-fold increase in ω − 3 fatty acids, primarily 22:5(ω − 3) and 22:6(ω − 3). The data suggest that membrane levels of cardiolipin and its ω − 3 fatty acid content modulate pyruvate transport in hypothyroid mitochondria.

Phospholipid fatty acid compositions of hepatopancreas and muscle from the prawn, Penaeus japonicus.

The hepatopancreas and muscle of the prawn, Penaeus japonicus, were analyzed as to the phospholipid fatty acid composition. The most important lipids in the hepatopancreas are triglycerides and phospholipids, while the lipids in muscle are principally phospholipids and free cholesterol. Fatty acids such as palmitic (16:0), stearic (18:0), oleic (18:1 n-9), eicosapentaenoic (20:5 n-3), and docosahexaenoic (22:6 n-3) were prominent in the total phospholipid fatty acid composition. However, phosphatidylethanolamine appeared to be particularly rich in n-3 polyunsaturated fatty acids, sphingomyelin in saturated fatty acids (mainly 18:0), and phosphatidylinositol in monounsaturated fatty acids (mainly 18:1 n-9). Our data indicated that each phospholipid class is characterized by a specific paraffin chain composition.

Long-Chain Fatty Acid Composition of Maternal Liver Lipids during Pregnancy and Lactation in the Rat: Comparison of Triglyceride to Phospholipid

The change in long-chain fatty acid composition in maternal liver was studied during pregnancy and lactation in the rat. Maternal liver triglycerides and phospholipids transiently accumulated and were depleted of long-chain fatty acids during pregnancy and lactation. During pregnancy, maternal liver accumulated triglyceride, but triglyceride fatty acid composition changed little. However, maternal liver total phospholipid fatty acid composition changed significantly without a change in the total pool size throughout pregnancy or lactation. The change in composition of (n-3) and (n-6) essential fatty acids in maternal liver triglyceride and total phospholipid occurred in an apparently dyssynchronous manner throughout pregnancy and lactation.

Isoprenoid fatty acids from marine sponges. Are sponges selective?

The burrowing sponges Anthosigmella varians and Spheciospongia vesparium were found to be rich in the isoprenoid phospholipid fatty acid 4,8,12-trimethyltridecanoic (5.2% and 23%, respectively, of the total fatty acid composition), while the burrowing sponge Chondrilla nucula and the demosponge Agelas dispar contained the acid 3,7,11,15-tetramethylhexadecanoic (13.8% and 8.6%, respectively, of the total phospholipid fatty acid composition). No other isoprenoid fatty acid was found, and the two acids described in this work did not occur concomitantly in the same sponge.

Membrane fluidity and thromboxane synthesis in platelets from patients with severe atherosclerosis

Platelets play an important role in the development of atherosclerosis. The arachidonic acid, whose oxygenated metabolites are potent regulators of the platelet-vessel wall interactions, is released from membrane phospho-lipids by the phospholipase(s) system(s). These membrane-linked phenomena are strongly modulated by the membrane physical properties. The present study was carried out to investigate the relationship between membrane fluidity and arachidonic acid metabolism in platelets from atherosclerotic patients. Twenty-one patients with peripheral vascular disease and twelve controls were studied. Platelets from patients showed an increase in membrane fluidity and enhanced thrombin-stimulated thromboxane synthesis. No alterations were found, however, in total phospholipid fatty acid composition. A significant decrease in the cholesterol/phospholipid ratio could account for the alterations in the membrane physical properties described in the platelets from patients.

Phospholipid fatty acid composition and cold tolerance in two species of barnacle, Balanus balanoides (L.) and Elminius modestus Darwin. II. Isolation and phospholipid fatty acid composition of subcellular membrane fractions

Homogenates were prepared from whole bodies of the intertidal barnacles, Balanus balanoides (L.) and Elminius modestus Darwin in winter and summer. The homogenates were subject to fractionation using differential and sucrose density gradient centrifugation. Three principle fractions were obtained which, according to marker enzyme analysis, were enriched with respect to plasma membranes, mitochondria, and endoplasmic reticulum, respectively. Contamination of plasma membranes and mitochondria fractions by other organelles was low. This was confirmed by examination by electron microscopy of fractions prepared from E. modestus. The fatty acid compositions of total phospholipids isolated from subcellular fractions of both species were determined. In general, polyunsaturation decreased in the order mitochondria > endoplasmic reticulum > plasma membranes. In the mitochondria and endoplasmic reticulum fractions from Balanus balanoides the saturated fatty acid level increased from winter to summer while the monounsaturated fatty acids decreased. The level of polyunsaturation in mitochondria also decreased. In the plasma membrane fraction the level of saturated fatty acids increased markedly in summer while that of mono- and polyunsaturated fatty acids decreased. Changes in the total phospholipid fatty acid composition of mitochondria and endoplasmic reticulum fractions prepared from Elminius modestus were similar to those noted in Balanus balanoides except that in Elminius modestus, the level of saturated fatty acids decreased in mitochondria. In the plasma membrane fraction from E. modestus the level of polyunsaturation increased in the summer in contrast to the results obtained with Balanus balanoides. This study suggests that the differences between the two species with respect to their ability to acquire freezing tolerance may be related to seasonal changes in total phospholipid fatty acid composition of the plasma membrane.

The effects of membrane fatty acid modification of clonal pheochromocytoma cells on depolarization-dependent exocytosis.

We have begun studying the role of membrane lipids in the exocytotic release process using the pheochromocytoma clone, PC12. The phospholipid fatty acid composition of the cells was modified by growth in the presence of specific fatty acids. None of the fatty acid modifications affected K+-stimulated release of [3H] norepinephrine. This observation indicates that the individual steps of the secretion process, including the extent of depolarization produced by K+, the response of the voltage-dependent Ca2+ channels to depolarization, and the subsequent steps in Ca2+-dependent exocytosis were unaffected by the fatty acid changes. In contrast, exocytosis evoked by stimulation of nicotinic cholinergic receptors with carbamylcholine or direct activation of action potential Na+ channels with veratridine was diminished in cells enriched with unsaturated fatty acids. The diminished output of the release systems was observed at all concentrations of carbamylcholine and veratridine tested. Since the events of exocytosis subsequent to Ca2+ influx were unaffected by unsaturated fatty acids, it appears likely that the magnitude of the depolarization produced by carbamylcholine and veratridine was reduced. The loss of carbamylcholine-stimulated release did not correlate with the simple presence of the fatty acids, but paralleled closely the time and concentration-dependent changes in the phospholipid fatty acid composition. However, when oleate and arachidonate were simultaneously added to the culture medium, the inhibitory effects on carbamylcholine-stimulated release were additive, whereas the changes in fatty acid composition were antagonistic. Thus, exposure of PC12 cells to unsaturated fatty acids causes specific, reversible decreases in the activities of at least 2 stimulus/secretion systems. However, the mechanistic explanation for these changes is not readily apparent from a simple analysis of total phospholipid fatty acid composition.