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Plasmalogens (Pls) are phospholipids containing a vinyl–ether bond at the sn -1 position of the glycerol backbone. They represent between 1/2 and 2/3 of the ethanolamine phospholipids in the brain. During aging, the Pls content in human brain falls down. However, the role of Pls metabolism-related enzymes in the regulation of Pls levels remains to be determined. Dihydroxyacetone phosphate acyltransferase (DHAP-AT) is the enzyme involved in the first step of Pls biosynthesis. In the brain, a phospholipase A 2 , which selectively acts on Pls, has been isolated (Pls-PLA 2 s). In this work, we aimed to evaluate the impact of DHAP-AT (a key enzyme of Pls biosynthesis) and Pls-PLA 2 (a specific Pls degradation enzyme) on the evolution of Pls content in the rat brain during aging. The influence of n-3 fatty acid intake was also evaluated. Littermates from two generations of n-3 deficient rats were fed an equilibrated diet containing either α-LNA alone or with two doses of DHA. After weaning, 3, 9 or 21 months of diet, rats were sacrificed. Enzymatic assays were performed, Pls levels were assessed and the sn -2 position of ethanolamine Pls was analyzed. DHAP-AT activity significantly increased between weaning and 3 months with a concomitant increase of brain Pls, which reached maximal levels after 9 months. Then, Pls levels and DHAP-AT activity significantly decreased while Pls-PLA 2 s activity significantly increased. Dietary n-3 fatty acids had no effect on DHAP-AT activity and on Pls levels. In conclusion, the increase of brain Pls content in the first part of the life may be related to the high increase of DHAP-AT activity, probably stimulated by DHA. In aged animals, the decrease of Pls levels may mainly be caused to an increase of their degradation by Pls-PLA 2 . Dietary DHA may not oppose the physiologic aging.

Long-chain polyunsaturated fatty acids (LC-PUFA) of the n-3 series, particularly eicosapentaenoic (EPA) and docosahexaenoic (DHA) acid, have specific activities especially in the functionality of the central nervous system. Due to the occurrence of numerous methylene-interrupted ethylenic double bonds, these fatty acids are very sensitive to air (oxygen) and temperature. Non-volatile degradation products, which include polymers, cyclic fatty acid monomers (CFAM) and geometrical isomers of EPA and DHA, were evaluated in fish oil samples obtained by deodorization under vacuum of semi-refined fish oil at 180, 220 and 250 °C. Polymers are the major degradation products generated at high deodorization temperatures, with 19.5% oligomers being formed in oil deodorized at 250 °C. A significant amount of CFAM was produced during deodorization at temperatures above or equal to 220 °C. In fact, 23.9 and 66.3 mg/g of C20 and C22 CFAM were found in samples deodorized at 220 and 250 °C, respectively. Only minor changes were observed in the EPA and DHA trans isomer content and composition after deodorization at 180 °C. At this temperature, the formation of polar compounds and CFAM was also low. However, the oil deodorized at 220 and 250 °C contained 4.2% and 7.6% geometrical isomers, respectively. Even after a deodorization at 250 °C, the majority of geometrical isomers were mono- and di-trans. These results indicate that deodorization of fish oils should be conducted at a maximal temperature of 180 °C. This temperature seems to be lower than the activation energy required for polymerization (intra and inter) and geometrical isomerization.

Structural determination of polyunsaturated fatty acids by gas chromatography–mass spectrometry (GC–MS) requires currently the use of nitrogen containing derivatives such as picolinyl esters, 4,4-dimethyloxazoline or pyrrolidides derivatives. The derivatization is required in most cases to obtain low energy fragmentation that allows accurate location of the double bonds. In the present work, the following metabolites of rumelenic ( cis- 9, trans -11, cis -15 18:3) acid, from rat livers, were identified: cis -8, cis -11, trans -13, cis -17 20:4, cis -5, cis -8, cis -11, trans -13, cis -17 20:5, cis -7, cis -10, cis -13, trans -15, cis -19 22:5, and cis -4, cis -7, cis -10, cis -13, trans -15, cis -19 22:6 acids by GC–MS as their 4,4-dimethyloxazoline and methyl esters derivatives. Specific fragmentation of the methyl ester derivatives revealed some similarity with their corresponding DMOX derivatives. Indeed, intense ion fragments at m / z = M + − 69, corresponding to a cleavage at the center of a bis-methylene interrupted double bond system were observed for all identified metabolites. Moreover, intense ion fragments at m / z = M + − 136, corresponding to allylic cleavage of the n -12 double bonds were observed for the C20:5, C22:5, C22:6 acid metabolites. For the long chain polyunsaturated fatty acids from the rumelenic metabolism, we showed that single methyl esters derivatives might be used for both usual quantification by GC–FID and identification by GC–MS.

In a recent study, we observed some oxyphytosterols in the plasma of healthy human subjects. This experiment was effected in order to determine if these compounds could be formed in vivo from phytosterols. Rats were fed with a high level of phytosterols (1% of the diet) and they were compared to rats deprived of phytosterols, using triglycerides purified from phytosterols. Their plasma were analysed for the main oxyphytosterols. The results show that sitostanetriol and campestanetriol were not formed in vivo from phytosterols. Their levels decreased during the experiment. The diet origin is highly probable for the compounds identified in human plasma. In particular, it seems that the sitostanetriol is eliminated very slowly from the organism.

Pure individual phytosterols were prepared using reversed-phase HPLC in order to obtain the oxidized compounds of sitosterol, campesterol, stigmasterol and brassicasterol. 7-Hydroxy-, 7-keto-, 5,6-epoxy-, 4beta-hydroxy-, 4-ene-6-hydroxy-, 6-keto- and 5alpha,6beta-dihydroxyphytosterols were obtained as well as analogous compounds of cholesterol. The gas chromatographic properties as well as the electronic impact mass spectra of these compounds (as trimethylsilyl ether derivatives) were studied. These data were used to identify oxyphytosterols in a spread enriched in phytosterols: the oxyphytosterols represented no more than 68 microg/g of spread (about 0.08% of phytosterols were oxidised).

Formation of trans fatty acids and cyclic fatty acid monomers was investigated during refining of low erucic acid rapeseed oil. The first steps of the refining process, that is, degumming, neutralization, and bleaching, hardly modified the fatty acid profile. In contrast, deodorization produced substantial quantities of trans fatty acids (>5% of total fatty acids) and small amounts of cyclic fatty acid monomers (650 mg of cyclic fatty acid monomers/kg of oil) when severe conditions (5-6 h at 250 degrees C) were used. Alpha-linolenic acid was the main precursor of cyclic fatty acid monomers. The influence of deodorization on the chemical composition of low erucic acid rapeseed oil was studied additionally. Whereas free fatty acids, peroxides, and tocopherols decreased, neither total polar compounds nor oxyphytosterols changed during deodorization. Oxyphytosterols were identified by GC-MS. Three oxyphytosterols not yet observed in oil were tentatively identified as 6beta-hydroxycampestanol, 6beta-hydroxysitostanol, and 6beta-hydroxybrassicastanol. Brassicasterol oxides were the most abundant oxyphytosterols.

Silver ion-high-performance liquid chromatography (HPLC) has been commonly used for the separation and the analysis of trans-18:1 isomers in partially hydrogenated oils and milk fat. This paper describes an easy HPLC method using two reversed-phase columns. The cis- and trans-18:1 fatty acids isomers as methyl esters were eluted as two separate fractions. The collected fractions were analysed by gas chromatography (GC). The purity of the two fractions were tested by GC-MS and GC-Fourier transform IR.

Conjugated linoleic acid (CLA) is a collective term that describes different isomers of linoleic acid with conjugated double bonds. Although the main dietary isomer is 9cis,11trans-18:2, which is present in dairy products and ruminant fat, the biological effects of CLA generally have been studied using mixtures in which the 9cis,11trans- and the 10trans,12cis-18:2 were present at similar levels. In the present work, we have studied the impact of each isomer (9cis,11 trans- and 10trans,12cis-18:2) given separately in the diet of rats for 6 wk. The 10trans,12cis-18:2 decreased the triacylglycerol content of the liver (-32%) and increased the 18:0 content at the expense of 18:1 n-9, suggesting an alteration of the delta9 desaturase activity, as was already demonstrated in vitro. This was not observed when the 9cis,11trans-18:2 was given in the diet. Moreover, the 10trans,12cis-18:2 induced an increase in the C22 polyunsaturated fatty acids in the liver lipids. The 10trans,12cis-18:2 was mainly metabolized into conjugated 16:2 and 18:3, which have been identified. The 9cis,11trans isomer was preferentially metabolized into a conjugated 20:3 isomer. Thus, the 9cis,11trans- and the 10trans,12cis-CLA isomers are metabolized differently and have distinct effects on the metabolism of polyunsaturated fatty acids in rat liver while altering liver triglyceride levels differentially.

Male weanling Wistar rats (n = 15), weighing 200-220 g, were allocated for 6 wk to diets containing 1% (by weight) of conjugated linoleic acid (CLA), either as the 9c,11 t-isomer, the 10t,12c-isomer, or as a mixture containing 45% of each of these isomers. The five rats of the control group received 1% of oleic acid instead. Selected enzyme activities were determined in different tissues after cellular subfractionation. None of the CLA-diet induced a hepatic peroxisome-proliferation response, as evidenced by a lack of change in the activity of some characteristic enzymes [i.e., acyl-CoA oxidase, CYP4A1, but also carnitine palmitoyltransferase-I (CPT-I)] or enzyme affected by peroxisome-proliferators (glutathione S-transferase). In addition to the liver, the activity of the rate-limiting beta-oxidation enzyme in mitochondria, CPT-I, did not change either in skeletal muscle or in heart. Conversely, its activity increased more than 30% in the control value in epididymal adipose tissue of the animals fed the CLA-diets containing the 10t,12c-isomer. Conversely, the activity of phosphatidate phosphohydrolase, a rate-limiting enzyme in glycerolipid neosynthesis, remained unchanged in adipose tissue. Kinetic studies conducted on hepatic CPT-I and peroxisomal acyl-CoA oxidase with CoA derivatives predicted a different channeling of CLA isomers through the mitochondrial or the peroxisomal oxidation pathways. In conclusion, the 10t,12c-CLA isomer seems to be more efficiently utilized by the cells than its 9c,11t homolog, though the Wistar rat species appeared to be poorly responsive to CLA diets for the effects measured.

Rats were fed a fat-free diet for 2 wk. After this period, while maintaining the animals on the same diet, the rats were given intragastrically 180 mg per day of a mixture of conjugated linoleic acids (CLA) as triacylglycerols. Gas chromatography mass spectrometry (GC-MS) analyses of this mixture, as well as hydrazine reduction and GC-MS and GC-Fourier transform infrared analyses of the resulting monoenes, revealed the presence of two major isomers, the 9c,11t- and the 10t,12c-18:2 accompanied by smaller amounts of the 8t, 10c and the 11c, 13t-18:2 isomers. Minor quantities of cis,cis and trans,trans conjugated isomers also were detected. The total fatty acid methyl esters from the liver lipids were fractionated by reversed-phase high-performance liquid chromatography, and the fraction containing the 20:4 isomers was further fractionated by silver nitrate thin-layer chromatography. A band containing two 20:4 conjugated isomers was submitted to hydrazine reduction and the resulting monoenes analyzed by GC-MS as dimethyl-oxazoline derivatives. The two conjugated isomers were tentatively identified as 5c,8c, 11c, 13t-20:4 and 5c,8c,12t,14c-20:4. These could be formed by desaturation and elongation of the 9c,11t- and 10t,12c-18:2 present in the commercial CLA mixture.

Pure conjugated isomers of linoleic acid were prepared on a large scale by alkali-isomerization of purified methyl linoleate. The methyl esters of alkali-isomerized linoleic acid contained mainly the methyl cis-9,trans-11- and trans-10,cis-12-octadecadienoates (44 and 47%, respectively). These two isomers were then separated and purified by a series of low-temperature crystallizations from acetone. The isomeric purity obtained for the cis-9,trans-11-octadecadienoate isomer was >90% and that of the trans-10,cis-12-octadecadienoate isomer was 89 to 97%. The isolated yield of the two isomers corresponded to 18 and 25.7%, respectively, of the starting material. The structure of the two isomers was confirmed using partial hydrazine reduction, silver nitrate-thin-layer chromatography of the resulting monoenes and gas chromatography coupled with mass spectrometry of the 4,4-dimethyloxazoline derivatives. Fourier transform infrared spectroscopy of the monoenes gave the confirmation of the geometry of each double bond.

Trans isomers of α linolenic acid are formed during heat treatment of vegetable oils. As a consequence, they are present in the human diet. Their effects on biological functions are not yet fully understood. In the present work, the effects of dietary trans n-3 fatty acids on the rat electroretinogram (ERG) were studied, as the retina is a tissue particularly rich in n-3 fatty acids. An isolated perfused rat retina model was used in order to monitor the b-wave of the ERG. A diet containing ethyl esters of trans α linolenic acid isomers or not (control) was given to Wistar male rats for 6 weeks. The incorporation of C22:6 Δ 19 trans fatty acid was studied after this feeding period. Dietary trans isomers of n-3 fatty acids significantly altered the maximal b-wave amplitude of the isolated retina. The low trans isomers incorporation in the total retina lipids suggests that further studies are needed to clarify how dietary trans n-3 fatty acids may act.

We investigated the intestinal digestion of cyclic fatty acid monomers (CFAM) isolated from heated linseed oil and their effects upon fatty acid lymphatic transport and lipoprotein profile in lymph. These cyclic fatty acid monomers were acylated in specific positions in the glycerol backbone of triacylglycerols (sn-(1/3) position for the 1C oil, sn-2 position for the 2C oil and together in the sn-1,2, and 3 positions for the 3C oil) and administered intragastrically to lymph-canulated rats. Their lumenal digestibility was also assessed in vitro using a pancreatic lipase assay. The lipase activity was 1.9 to 6.6 less towards the triacylglycerols acylated with cyclic fatty acids compared to control. The lowest activity was with the 2C oil. In the hydrolytic products, the cyclic fatty acid contents were similar between the experimental groups. When absorbed as 2-monoacyl-sn-glycerol (2C oil), cyclic fatty acid monomers were better and unselectively recovered into the lymph than when absorbed as free fatty acids (1C oil). In that latter situation, the bulkier cyclic fatty acids (C6 and cis membered-ring CFAM) were transported into the lymph to a lesser extent. The appearance of the lymphatic chylomicrons was delayed in rats fed the 1C oil. Cyclic fatty acid monomers from the 2C oil only increased the lymphatic transport of saturated fatty acids (80%). Cyclic fatty acids from the 3C oil (absorbed as 2-monoacyl-sn-glycerol and free fatty acid) usually elicited intermediary effects. We conclude that the effects of cyclic fatty acid monomers upon the intestinal metabolism are greatly influenced by their positioning within the triacylglycerol and that the structure of the cyclic fatty acids influences their lymphatic recovery only when they are absorbed as free fatty acid.

A recent study showed that human platelets may contain some EPA and DHA geometrical isomers. Previous data from our laboratory showed that these isomers can compete in vitro with arachidonic acid metabolism in platelets and alter aggregation. However, the effects of these isomers, when present in platelet lipids, has not yet been investigated. Human platelets were enriched with EPA, DHA or their respective Δ 17 or Δ 19 trans isomers in order to study the effects of these fatty acids on platelet aggregation and arachidonic acid metabolism. Platelets were stimulated by collagen or by the TxA 2 -stable analog, U46619. Both trans isomers of EPA and DHA were less antiaggregant than their respective cis analogs when platelets were stimulated by collagen. However, the metabolism of arachidonic acid into HHT, 12 HETE and TxB 2 was apparently not modified. The response to U46619 was only slightly and not significantly modified by trans versus cis 20:5 and 22:6 fatty acids. It can be concluded that trans polyunsaturated fatty acids have different physiological effects than their respective cis homologues on platelet function, but the mechanisms by which they act needs further work to be totally elucidated.

Geometrical isomers of essential fatty acids are formed during heat treatment of vegetable oils. They are subsequently present in human diet. They have been reported to be elongated, desaturated and incorporated in many rat tissues. The aim of the present study was to consider the incorporation of trans (n-3) fatty acids in the rat retina, which is a docosahexaenoic acid (DHA)-rich tissue and often described as a protected structure against xenobiotics. Rats were fed for up to 8 weeks with a heated linseed oil, which is rich in geometrical isomers of linolenic acid. Isomers of linolenic acid, but also of eicosapentaenoic acid (EPA) and DHA were found in the retina. The incorporation of the latter is time-dependent, whereas the Δ 17 trans isomer of EPA increased strongly after 8 weeks of diet while it remained almost constant until 8 weeks. The percentage of incorporation of the trans isomer of DHA is almost the same than in the liver after 8 weeks of diet. It suggests that the retina may not be much more protected than the liver against long chain trans fatty acid incorporation.

Human platelets fatty acid profiles were studied with particular interest to isomers of eicosapentaenoic and docosahexaenoic acids. C20:5 Δ 17 trans isomer was detected in most of the samples (up to 0.48% of total fatty acids). Some samples also contained the Δ 19 trans isomer of docosahexaenoic acid (0.05% max.).

Trois huiles de tournesol ont ete choisies pour leur teneur elevee en composes polaires (superieure a 25 %). Les huiles ont ete methylees par du methanolate de sodium selon la methode de Carreau et Dubacq (J Chromat, 1978). Le dosage des ALC a ete realise par CLHP-CI8 couplee a un detecteur a barrette de diodes. Pour l'identification des ALC, la fraction contenant les 18:2 et les ALC-OL ete separees des autres esters methyliques par CLHP-Cl8 ; puis une CCM impregnee au nitrate d'argent a permis d'isoler les ALC des isomeres non conjugues de l'acide linoleique. L'identification des ALC a ete realisee par CPG sur colonne CPSil88 de 100 m, et par CPG-SM des derives MTAD et DMOX.

International audience; Among several theories involved in the pathogenesis of primary open-angle glaucoma (POAG), the vascular theory considers the disease to be a consequence of reduced ocular blood flow associated with red blood cell abnormalities. Red blood cell membrane structure and function are influenced by their phospholipid composition. We investigated whether specific lipid entities that may affect the membrane physiology, namely, polyunsaturated fatty acids (PUFAs) and plasmalogens, are modified in POAG and whether these potential variations are related to the stage of glaucoma. Blood samples were collected from 31 POAG patients and 10 healthy individuals. The stage of glaucoma was determined according to the Hodapp and Parrish classification. Lipids were extracted from red blood cell membranes and individual phospholipid species were quantified by liquid chromatography combined with mass spectrometry using triple quadrupole technology. POAG patients had reduced erythrocyte levels of phosphatidyl-choline (PC) carrying docosahexaenoic acid (DHA). POAG patients also displayed lower levels of choline plasmalogens (PlsC) carrying PUFAs other than DHA. These differences were greater as the severity of the disease increased. Linear regressions predicted that red blood cell PlsC levels would decrease years before clinical symptoms, whereas the levels of PC carrying DHA were linearly correlated to visual field loss. Our data demonstrate the selective loss of some individual phospholipid species in red blood cell membranes, which may partly explain their loss of flexibility in POAG.

Purpose Accumulation of lipids, and especially of cholesteryl esters, under the retinal pigment epithelium and within Bruch’s membrane is a normal feature of aging and has also been observed in human eyes with age-related maculopathy. Our objective was to evaluate the retinal phenotype of apoB100,LDLR-/- mice, a model for lipid metabolism dysfunction and potentially of aging of the retina. Methods ApoB100,LDLR-/- mice were studied at 7 and 14 months of age by standard scotopic and photopic electroretinography by comparison to control animals. Fundus images were obtained with a confocal SLO (Heidelberg Retina Angiograph). The integrity of the vascular system was investigated by means of fluoresceine and indocyanine green angiography. Sections of eye cups were stained by filipin to detect cholesterol deposits. Results Both scotopic and photopic b-wave amplitudes were reduced in apoB100,LDLR-/- mice compared to control mice (Rmax=125 µV vs 208 µV for the scotopic b-wave amplitude at 7 months, and 83 µV vs 162 µV at 14 months). Similarly rods and cones sensitivity was 0.5log unit lower in apoB100,LDLR-/- mice at 14 months, compared to control mice. Although the retinal and the choroidal vascular systems were normal, apoB100,LDLR-/- mice displayed white auto-fluorescent dots in the retinal pigment epithelium layer which likely corresponded to cholesterol deposits. Conclusion The present apoB100,LDLR-/- mouse, is one of the only models with neutral lipid deposits at the basement of RPE that can potentially be very useful to study the mechanisms of lipid deposition that occurs universally in human retina while aging.

International audience; Purpose: Lipids represent 50% of retinal dry matter. Within structural phospholipids, ether-lipids are a major class but their exact species, concentrations and functions in the retina are still unknown. A defect in their biosynthesis is observed in peroximal disorders like Rhizomelic Chondrodysplasia Punctata type 2 and 3 (RCDP) characterized by retinal pigment epithelium (RPE) degeneration and defects in ocular vasculogenesis. The aim of this work was to perform a detailed study of the retinal composition in ether-lipids. Methods: Total lipids were purified from calf retina and RPE samples. The proportion of major lipid classes was determined by thin-layer chromatography (TLC). Phospholipids were separated from non-phosphorus lipids by liquid chromatography (LC), subclasses (linked with ethanolamine, choline, serine or inositol) were quantified by LC and then purified by TLC. The fatty acid composition of each subclass was evaluated by gas chromatography (GC). The expression of the key enzyme of ether-lipids biosynthesis (DHAP-AT) was evaluated by reverse-transcriptase polymerase chain reaction (RT-PCR) on calf retina and RPE samples and its cellular localization was performed on rat retina semi-thin sections by in situ hybridization. Results: Phospholipids represent 85% of retinal and RPE lipids. Within phospholipids 41% and 36% were linked with ethanolamine in the retina and the RPE, respectively. Ether-lipids accounted for 30% of ethanolamine-linked phospholipids in both the retina and the RPE. In the retina, 67% of ethanolamine ether-lipids contained stearic acid in position 1 of glycerol, and 15% contained palmitic acid. Stearic acid accounted for 38% and palmitic acid for 41% in the RPE. DHAP-AT was expressed in both, retinal and RPE cells and its expression within the retina was mainly localized in the photoreceptor inner segments and in bipolar cells to a lesser extent. Conclusions: Our results illustrate the quantitative importance of ether-lipids and particularly those linked to ethanolamine in retinal and RPE cells. According to these results and considering their putative structural and metabolic roles in other tissues, ether-lipids may play a crucial role in retinal physiology as illustrated by their lack in RCDP patients.

This work describes a one-step separation of rat tissue phospholipid classes by high-performance liquid chromatography (HPLC) using a silica column and a new light-scattering detector (LSD). Complete separation of phosphatidylcholine, phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylinositol, phosphatidylserine, sphingomyelin, lysophosphatidylethanolamine, and lysophosphatidylcholine was obtained. Direct quantification was achieved after detector calibration for each phospholipid class. The detector response was shown to be linear within the ranges used. The LSD results agreed well with those obtained by phospholipid phosphorus assay. The present method was applied to rat heart and rat liver phospholipid analysis.

Publisher Summary Deep fat frying is one of the most common procedures for the preparation of food. In this process, fat is exposed to high temperatures in the presence of air and food containing water. Consequently, many chemical reactions take place during this process. Hydrolysis results in the formation of fatty acids, monoglycerides, and diglycerides, while the presence of air and high temperatures gives rise to the formation of thermal and oxidation alteration products. Oxidation products may include oxidized monomeric, dimeric, and oligomeric triglycerides, as well as volatiles components such as aldehydes, ketones, hydrocarbons, etc. Thermal alteration products include Cyclic Fatty Acid Monomers (CFAM), fatty acid geometrical isomers, non-polar dimeric, and oligomeric triglycerides. Thus, frying is a complex situation where many reactions take place. This chapter reviews the structural analysis and identifications of geometrical fatty acids isomers, including those having a conjugated system, and the CFAM formed from both essential fatty acids and linolenic acids. It also describes the methods of analysis, quantification, and levels in food products and, emphasizing on the CFAM, considers the great number of studies carried out on these molecules.

International audience; Long-chain polyunsaturated fatty acids (LC-PUFAs) of the n-3 series and especially eicosapentaenoic and docosahexaenoic acids (EPA and DHA, respectively) have important biological properties. The main dietary sources of LC-PUFAs are fish and fish oil. Geometrical isomerization is one of the main reactions happening during the thermal treatment of polyunsaturated fatty acids. Refined fish oils are used to supplement food products in LC-PUFAs and the quality of these nutritional ingredients have to be controlled. In the present study, a suitable method for the quantification of EPA and DHA geometrical isomers in fish oils by gas–liquid chromatography (GC) is presented. A highly polar capillary column (CP-Sil 88, 100 m) operating under optimal conditions was used. Method selectivity was studied by GC–mass spectrometry. The performance characteristics of the quantification method were studied using samples of fish oil deodorized at 220 °C for 3 h. The linearity of the method was assessed by analyzing composite samples obtained by mixing fish oil deodorized at 220 °C with semi-refined fish oil (control). Precision was evaluated by analyzing the same samples in triplicate. Results showed that the validated method is suitable to quantify low amounts of geometrical (trans) isomers of EPA and DHA in refined fish oils. The limits of quantification of the EPA and DHA geometrical isomers are 0.16 and 0.56 g/100 g of fish oil, for EPA and DHA, respectively. Commercially available LC-PUFA oil samples were evaluated by using the validated method. The results show that the oils analyzed contain low amounts (

International audience; Adequate analytical tools are required for labelling food products for trans fatty acid (TFA) contents. The choice of the fatty acid (FA) derivatisation is a crucial step in obtaining good results, in particular with short-chain and conjugated FA. Several gas chromatographic and infrared spectrophometric methods have been developed for analysing TFA in foods, some of which have been validated as official methods after collaborative studies. Complete analysis of total FA often requires the use of complementary high-performance liquid chromatography methods. This paper reviews the analytical methods developed for identifying and quantifying TFA in foods and presents the official methods of analysis. Neither of these analytical methods enables a TFA naturally occurring in basic food to be distinguished from a TFA formed during an industrial process.

International audience; Most of fatty acid double bonds are in cis configuration, but some processes may isomerise double bonds from cis to trans configuration and from their naturally occurring positions in the carbon chain. Since some fatty acids with trans double bond(s) are suspected to have adverse effects, several countries have regulated the inclusion of trans fatty acid (TFA) content labelling. The French governmental authorities requested AFSSA to propose recommendations regarding food labelling. This first article summarises the discussion on a regulatory TFA definition and reviews the occurrence and origins of TFA in foods. From a chemical point of view, a TFA is any kind of fatty acid that has one or more double bond(s) in trans configuration, but restricted TFA definitions have been proposed for food labelling purposes. These definitions exclude fatty acids with conjugated double bonds on different criteria which are commented on in this paper. Taking into account the goal of TFA labelling and the potential harmful properties of some trans conjugated fatty acids, the working group proposes the chemical definition for TFA labelling purposes. The main TFA natural origin is ruminal biohydrogenation, and therefore TFA are present in dairy products and ruminant meat. TFA are also found in domestically or industrially processed foods due to hydrogenation or heat treatment effects on oils and fats. Although the TFA molecules produced by both natural and industrial processes are often quite similar, TFA distribution profiles and levels are very different from one case to another.

International audience; Thirty lactating dairy cows were used in a 333 Latin-square design to investigate the effects of a raw or extruded blend of linseed and wheat bran (70:30) on plasma and milk fatty-acids (FA). Linseed diets, containing 16.6% linseed blend on a dry-matter basis, decreased milk yield and protein percentage. They decreased the proportions of FA with less than 18 carbons in plasma and milk and resulted in cis -9, cis -12, cis -15 18:3 proportions that were more than three and four times higher in plasma and milk, respectively, whereas cis -9, cis -12 18:2 proportions were decreased by 10–15%. The cis -9, trans -11, cis -15 18:3 isomer of conjugated linolenic acid was not detected in the milk of control cows, but was over 0.15% of total FA in the milk fat of linseed-supplemented cows. Similarly, linseed increased plasma and milk proportions of all biohydrogenation (BH) intermediates in plasma and milk, including the main isomer of conjugated linoleic acid cis -9, trans -11 18:2, except trans -4 18:1 and cis -11, trans -15 18:2 in plasma lipids. In milk fat, compared with raw linseed, extruded linseed further reduced 6:0–16:0 even-chain FA, did not significantly affect the proportions of 18:0, cis -9 18:1 and cis- 9, cis -12 18:2, tended to increase cis -9, cis -12, cis -15 18:3, and resulted in an additional increase in the proportions of most BH intermediates. It was concluded that linseed addition can improve the proportion of conjugated linoleic and linolenic acids, and that extrusion further increases the proportions of intermediates of ruminal BH in milk fat.

International audience; Plasmalogens (Pls) are phospholipids containing a vinyl-ether bond in the sn-1 position of the glycerol backbone. The physiological role of Pls is still enigmatic, especially within the eye where their deficiency leads to developmental abnormalities. In order to learn more about the functions of Pls in the posterior eye, we evaluated retinal Pl content as well as the expression of the first enzyme involved in Pls biosynthesis, dihydroxyacetone phosphate acyltransferase (DHAP-AT) in the retina. In situ hybridization of DHAP-AT mRNA was performed on rat eye sections. The Pl contents of calf retina and retinal pigment epithelium (RPE) samples were determined by high-performance liquid chromatography, thin-layer chromatography, and gas chromatography. DHAP-AT was highly expressed in the inner segment of photoreceptors and in the RPE, suggesting two distinct sites for Pl biosynthesis. Plasmenyl-ethanolamine was the prominent class of Pls in both neural retina and RPE (28–29% of the total phospho-ethanolamine-glycerides). According to the nature of the alkenyl residue linked to the sn-1 position of Pls, the most striking finding was the greater proportion of octadecanal-aldehyde in the sn-1 position of plasmenyl-ethanolamine of the neural retina compared to all the other classes of Pls in the neural retina and the RPE. These findings might be relevant to the biological functions of Pls against oxidative stress and in the formation of lipid rafts.

International audience; Addition of long-chain polyunsaturated fatty acids (LC-PUFAs) from marine oil into food products implies preliminary refining procedures of the oil which thermal process affects the integrity of LC-PUFAs. Deodorization, the major step involving high temperatures, is a common process used for the refining of edible fats and oils. The present study evaluates the effect of deodorization temperature on the formation of LC-PUFA geometrical isomers. Chemically isomerized eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) were used as reference samples. Fish oil samples have been deodorized at 180, 220 and 250 °C for 3 h and pure EPA and DHA fatty acid methyl esters (FAMEs) were chemically isomerized using p-toluenesulfinic acid as catalyst. FAMEs prepared from fish oil were fractionated by reversed-phase high-performance liquid chromatography (RP-HPLC). Geometrical isomers produced by both processes were fractionated by silver-ion thin-layer chromatography (Ag-TLC) and silver-ion high-performance liquid chromatography (Ag-HPLC). The FAME fractions were subsequently analyzed by gas chromatography (GC) on a 100 m highly polar cyanopropylpolysiloxane coated capillary column, CP-Sil 88. Our results show that thermally induced geometrical isomerization appears to be a directed reaction and some ethylenic double bond positions on the hydrocarbon chain are more prone to stereomutation. Only minor changes were observed in the EPA and DHA trans isomers content and distribution after deodorization at 180 °C. The analyses of EPA and DHA isomer fractions revealed that it is possible to quantify EPA geometrical isomers by GC using the described conditions. However, we notice that a mono-trans isomer of DHA, formed during both chemical and thermal treatments, co-elute with all-cis DHA. This feature should be taken into consideration for the quantification of DHA geometrical isomers.

International audience; The aging brain undergoes modifications in its lipid composition and, especially, in plasmalogen (Pl) levels. These phospholipids are known to be reservoirs of polyunsaturated fatty acids and often considered as endogenous antioxidants. The objectives of this study were to quantify Pls and free aldehydes (products of Pl oxidation) in the rat brain after 21 months of age and to determine the impact of dietary α-linolenic acid (ALA) and docosahexaenoic acid (DHA) on these levels. Rats (21 months) from 2 generations of n-3–deficient animals were fed either a n-3 fatty acid–deficient diet—a diet containing ALA alone or with 0.6% of DHA. At 21 months and after 3 or 5 months of diet, Pl, free aldehyde, and DHA levels were assessed in the hippocampus, cortex, and cerebellum. Plasmalogen levels significantly decreased in the cortex and cerebellum of n-3–deficient 24-month-old rats. Dietary ALA and DHA at nutritional levels have the same efficiency to restore DHA levels in the brain of aged rat. Plasmalogen and free aldehyde levels were not significantly influenced by dietary n-3 fatty acids. Plasmalogens were not more oxidized when phospholipids were enriched in DHA, compared with the situation of n-3 fatty acid deficiency. In conclusion, during aging, Pl levels decrease in some structures of the brain. The evolution of aldehyde levels may not explain changes occurring during physiologic aging. Lastly, the bioequivalence of dietary ALA and DHA as sources of docosahexaenoate accretion could be similar in aged rat brain.

Although many data are available concerning anticarcinogenic effects of industrial conjugated linoleic acid (CLA), few studies have reported the antitumour properties of CLA mixtures originating from ruminant products. The aim of the present study was to investigate thein vitroantiproliferative effects of beef CLA mixtures on breast, lung, colon, melanoma and ovarian human cancer cell lines. For this purpose, four fatty acid (FA) extracts prepared from beef lipid and varying in their CLA composition, their corresponding purified CLA-enriched fractions, and mixtures of pure synthetic CLA, the composition of which reproduced that of the four selected beef samples, were tested on cancer cell lines. Cancer cells were exposed for 48h to medium containing 100μm-FA and their proliferation was determined by quantifying cellular DNA content (Hoechst 33342 dye). Compared with cells incubated without FA, the number of cancer cells was reduced from 25 to 67% (Pcis-transisomers allowing the most important antiproliferative effect. Beef total FA exhibited a greater growth-inhibitory activity than their corresponding CLA-enriched fractions. These results suggested that either beef FA other than beef CLA could possess antiproliferative properties and/or the existence of complementary effects of non-conjugated FA and CLA, which could favour the antiproliferative properties of beef total FA.

International audience; The aging brain undergoes modifications in the lipid composition of cell membranes and especially in plasmalogens. These phospholipids represent between one-half and twothirds of the ethanolamine phospholipids in the brain. They are known to facilitate membrane fusion and act as endogenous antioxidants. During normal aging and in some pathological conditions, plasmalogen and DHA levels fall. In this context, we aimed to evaluate the influence of n−3 FA intake on plasmalogens in the brain during aging. Littermates from two generations of n−3-deficient rats were fed an n−3-deficient diet or an equilibrated diet containing either α-linolenic acid alone (α-LNA) or with two doses of DHA (0.3 or 0.6% w/w). After weaning, 9 mon of diet, or 21 mon of diet, plasmalogen levels were assessed, and the sn-2 substitutions of plasmenylethanolamines were analyzed in the cortex, striatum, and hippocampus. Our results showed that plasmalogen contents were not influenced by the diet. Plasmalogen levels were significantly decreased in aged rats compared with adults, whereas DHA levels increased in the hippocampus and remained stable in the cortex and striatum. DHA levels were significantly and similarly increased in total phospholipids and especially in plasmenylethanolamines after 9 mon of diet containing α-LNA alone or combined with DHA. This study showed that each structure sustained specific age-induced modifications. Dietary n−3 FA may not oppose the physiological decrease in brain plasmalogen levels during aging. Moreover, α-LNA appears to be equally as potent as preformed DHA at replacing DHA in the brain of our rat model.

Structural determination of polyunsaturated fatty acids by gas chromatography-mass spectrometry (GC-MS) requires currently the use of nitrogen containing derivatives such as picolinyl esters, 4,4-dimethyloxazoline or pyrrolidides derivatives. The derivatization is required in most cases to obtain low energy fragmentation that allows accurate location of the double bonds. In the present work, the following metabolites of rumelenic (cis-9,trans-11,cis-15 18:3) acid, from rat livers, were identified: cis-8,cis-11,trans-13,cis-17 20:4, cis-5,cis-8,cis-11,trans-13,cis-17 20:5, cis-7,cis-10,cis-13,trans-15,cis-19 22:5, and cis-4,cis-7,cis-10,cis-13,trans-15,cis-19 22:6 acids by GC-MS as their 4,4-dimethyloxazoline and methyl esters derivatives. Specific fragmentation of the methyl ester derivatives revealed some similarity with their corresponding DMOX derivatives. Indeed, intense ion fragments at m/z=M+-69, corresponding to a cleavage at the center of a bis-methylene interrupted double bond system were observed for all identified metabolites. Moreover, intense ion fragments at m/z=M+-136, corresponding to allylic cleavage of the n-12 double bonds were observed for the C20:5, C22:5, C22:6 acid metabolites. For the long chain polyunsaturated fatty acids from the rumelenic metabolism, we showed that single methyl esters derivatives might be used for both usual quantification by GC-FID and identification by GC-MS.

The CLA content and isomer profile were characterized among two subclasses of the native milk fat globules. The latter corresponded to two fractions obtained by a microfiltration process using Spring mixed milk, leading to small fat globules (SFG; d 32 ∼ 2.8 μ m ) in the microfiltrates and large ones (LFG; d 32 ∼ 5 μ m ) in the retentates. Relatively, SFG always contained more CLA than the LFG originating from the same mixed milk, though discrepancies among different milk samples were observed. The main CLA isomer was the cis -9, trans -11, the content of which tended to increase when the native milk fat globule size decreased (from 82.2% to 87.3% of total CLA isomers). Consequently, the SFG contained less trans -12, trans -14; trans -11, trans -13; trans -11, cis -13 and trans -8, cis -10 isomers than the corresponding LFG. However, the relative variation of some isomers between small and large fat globule from the same milk varied depending on milk origin and the potential of fat globule fractionation for influencing the content and distribution of CLA seems to be limited.

The impact of starch sources differing in their velocities of ruminal degradation on the milk fat of dairy cows was studied. The animals received diets containing a slowly degradable (potatoes) or rapidly degradable (wheat) starch concentrate (40% of the dry matter) in a total mixed diet. Milk fat was the only animal performance factor affected: Cows produced significantly less milk fat when fed the wheat diet than the potato diet (−3.3 g/kg, −122 g/d; P

The aims of this study were to determine whether CLA are formed during refining of vegetable oils and to study the level and composition of CLA during heating. The effects of three refining steps (neutralization, bleaching, and deodorization) were analyzed with respect to their effect on CLA content. Two temperatures (180 and 220°C) were used for heating; CLA appeared only after deodorization. The level of CLA was positively influenced by temperature. More CLA were present after treatment at 220°C than at 180°C (1.3 and 0.2% of total FA, respectively). The high temperature modified the relative proportions of the CLA isomers. The main CLA isomers in fresh or heated oils were the trans,trans ones (mainly 9,11 and 10,12 isomers).

To assess the oxidative metabolism of conjugated linoleic acid (CLA) isomers, rats were force-fed 1.5-2.6 MBq of [1-14C]-linoleic acid (9c,12c-18:2), -rumenic acid (9c,11t-18:2), or-10trans,12cis-18:2 (10t,12c-18:2), and 14CO2 production was monitored for 24 h. The animals were then necropsied and the radioactivity determined in different tissues. Both CLA isomers were oxidized significantly more than linoleic acid. Moreover, less radioactivity was recovered in most tissues after CLA intake than after linoleic acid intake. The substantial oxidation of CLA isomers must be considered when assessing the putative health benefits of CLA supplements.

Le but de ce travail est de rechercher la presence d'isomeres conjugues de l'acide linoleique (ALC) dans des huiles collectees en restauration par le Laboratoire interregional de la repression des fraudes, et de determiner les structures de ces composes. Trois huiles de tournesol, une huile d'arachide et une de colza ont ete choisies pour leur teneur elevee en composes polaires (superieure a 25 %). Les acides gras des huiles ont ete methyles par du methanolate de sodium selon la methode de Glass, Le pourcentage d'ALC a ete determine par chromatographie en phase gazeuse sur colonne CP Si188 de 100m. La teneur des differents isomeres conjugues a ete determinee par chromatographie en phase gazeuse et par chromatographie liquide haute performence sur colonnes impregnees au nitrate d'argent. L'identification des ALC a ete realisee par chromatographie en phase gazeuse couplee au spectre de masse des derives 4-methyl-1,2,4-triazoline-3,5-dione. Les huiles contiennent de 30 a 53 % de composes polaires. La teneur en ALC est comprise entre 0,4 et 0,5 %. Les 18:2 Δ9,11 et 10,12 sont les isomeres majoritaires. Les isomeres geometriques di-trans representent environ 50 % des isomeres conjugues de l'acide linoleique.

Reversed-phase high-performance liquid chromatography (RP-HPLC) and silver-ion high-performance liquid chromatography (Ag-HPLC) were successively combined for the separation of the longer-chain metabolites of conjugated linoleic acids (CLAs). Commercial silver nitrate-impregnated columns were used with an eluting solvent composed of a mixture of hexane–acetonitrile. Fatty acid methyl esters (FAMEs) from liver lipids of rats fed CLA were analysed. This method allowed separation both of the non-conjugated FAME, as C16:1, C18:2, C18:3, C20:4 and C22:5, but also the conjugated fatty acids like CLA, 8,12,14-20:3, 5,8,12,14-20:4 and 5,8,11,13-20:4. The presence of 8,11,13-20:3 is reported for the first time. This method is of interest for the isolation and identification of the C20 conjugated metabolites that cannot be resolved by gas chromatography. Furthermore, it allows the isolation of FAME for further characterisation by GC–mass spectrometry (MS).

The effect of very low levels of dietary long-chain n-3 fatty acids on delta 6 desaturation of linoleic acid (18:2n-6) and alpha-linolenic acid (18:3n-3), and on delta 5 desaturation of dihomo-gamma-linolenic acid (20:3n-6), in liver microsomes and its influence on tissue fatty acids were examined in obese and lean Zucker rats and in Wistar rats. Animals fed for 12 wk a balanced diet containing ca. 200 mg of long-chain polyunsaturated n-3 fatty acids per 100 g of diet were compared to those fed the same amount of alpha-linolenic acid. Low amounts of long-chain n-3 fatty acids greatly inhibited delta 6 desaturation of 18:2n-6 and delta 5 desaturation of 20:3n-6, while delta 6 desaturation of 18:3n-3 was not inhibited in Zucker rats and was even stimulated in Wistar rats. Inhibition of the biosynthesis of long-chain n-6 fatty acids was reflected in a decrease in arachidonic acid (20:4n-6) content of serum lipids when fasting, and also in the phospholipid fatty acids of liver microsomes. On the contrary, heart and kidney phospholipids did not develop any decrease in 20:4n-6 during fish oil ingestion. Docosahexaenoic acid (22:6n-3), present in the dietary fish oil, was increased in serum lipids and in liver microsome, heart, and kidney phospholipids.

A method has been developed for separation of linolenic acid and its seven isomers by HPLC on a silver-ion-loaded column. The standard 18:3 isomers, isolated from a heated linseed oil or prepared by isomerization of linolenic acid, were converted into phenacyl esters and detected by UV at 238 nm. The use of low temperature (10 °C) combined with a gradient of dichloromethane and methanol enabled separation of all the cis/trans isomers. The peaks were identified by comparison of ECL values with those of a standard mixture, by chromatographing collected HPLC fractions on a polar GC column. HPLC quantification was compared with GC analysis. There was satisfactory agreement between the tow methods. This method could be used for seperation, collection and quantification of 18:3 fatty acids with trans double bonds in different oils and foods.

Three groups of male Sprague-Dawley rats were fed for 4 weeks purified diets containing 15% by weight of oil mixtures varying in the nature and content of (n-3) polyunsaturated fatty acids (PUFA) but supplying similar levels of 18:2 (n-6) (10% of the total dietary fatty acids) and of saturated fatty acids (19% of the total fatty acids). The First diet (“Low 18:3”) contained small amounts of 18:3 (0.5% of the total fatty acids), the second (“18:3”) contained linolenic acid (10% of the total fatty acids) as the only source of (n-3) PUFA and the third one (“LC (n-3)”) contained the same amount of long chain (n-3) PUFA (mainly 20:5 and 22:6). Heart phospholipid classes were separated by HPLC, quantified and converted to methyl esters which were analyzed by GLC using glass capillary columns. Dietary consumption of “LC n-3” PUFA resulted in a much higher incorporation of 20:5 (n-3) and 22:6 (n-3) and a much lesser proportion of 20:4 n-6 in heart phosphatidylcholine (PC) and phosphatidylethanolamine (PE) than an equivalent intake of 18:3 (n-3). Dietary “LC n-3” PUFA but not “18:3” reduced the 18:2 (n-6) level and augmented the (n-3) PUFA in heart diphosphatidylglycerol (DPG). Long chain saturated and (n-3) PUFA of sphingomyelin (SPH) are respectively decreased and increased in rats fed marine (n-3) PUFA. Finally, significant increases of the “Unsaturation Index” of PC, PE, DPG and SPH were also seen in rats fed (n-3) PUFA enriched diets. Functional consequences of such fatty acid alterations are discussed.

Rapeseed oil fed to male weanling rats as 15% by weight of the diet for 2 months does not influence the plasma content of triglycerides (TG), phospholipids (PL), nonesterified fatty acids (NEFA) and cholesterol esters (CE), as compared to peanut oil and canbra oil (‘zero erucic acid’ rapeseed oil). However, the fatty acid spectra are changed: erucic acid and eicosénoïque acid from dietary rapeseed oil are mainly incorporated in TG and NEFA, less in PL and practically not at all in CE. Feeding time has little effect. Therefore, the immediate but temporary cardiac steatosis which is obtained in weanling rats fed rapeseed oil cannot be explained by modifications of the plasma TG or NEFA concentration and/or their fatty acid composition. Rapeseed and canbra oil increase the percentages of ω3-polyunsaturated fatty acids and of nervonic acid in plasma PL.

Male wistar rats fed purified diets containing 15% sunflower oil (SF) by weight, high erucic acid rapeseed oil (HEAR) or low erucic acid rapeseed oil (LEAR) for 12 weeks and subjected to a moderate treadmill running program were compared with sedentary animals fed the same diets on the basis of cardiac morphology and complete analysis of cardiac phospholipids. HEAR caused the highest incidence and number of heart lesions both in untrained and trained rats but in the latter there was a highly significant increase of the lesions. LEAR gave a higher incidence of lesions than SF in untrained rats but not in trained ones. If compared to SF, HEAR and LEAR increased cardiac diphosphatidylglycerol (DPG) and sphingomyelin (SM) content (mg/g wet tissue) and decreased phosphatidylcholines (PC) and phosphatidylethanolamines (PE) in untrained rats. Marked changes in the fatty acid pattern of these phospholipids were also observed. PE and PC in trained and untrained rats fed HEAR or LEAR contained elevated levels of C 22:5 (n-3) and C 22:6 (n-3) fatty acids whereas the C 22:4 (n-6) and C 22:6 (n-6) polyenes disappeared. Monoenes (C 18:1, C 20:1 or C 22:1) largely incorporated in DPG of rats fed the cruciferous oils. In SM levels of saturated fatty acids (C 16:0, C 18:0, C 20:0) and of n-9 monoenes (C 18:1, C 20:1, C 22:1, C 24:1) were higher in rats fed HEAR or LEAR than in those feds SF. These changes were mainly related to the high level of n-9 monoenes (oleic, eicosenoic and erucic acids) as well as to the high ratio linolenic/linoleic acid present in cruciferous oils. Physical training interacted with the effects of these dietary oils on the cardiac phospholipid composition. The relation between changes in phospholipid composition and the incidence and the number of cardiac lesions is discussed.

Cardiac lipids (triglycerides and phospholipids) of weanling rats fed diets containing 15 % by weight of rapeseed oil (RSO), hydrogenated rapeseed oil (HRSO), trierucin (TE) or tribassidin (TB) were analyzed after 3 and 7 days of feeding. The amount of C22:1 was made equal in the 4 diets. Tarns-isomers of erucic acid found in HRSO and TB do not cause as high an accumulation of lipids and docosenoic acids in the heart as erucic acid. Digestibility of brassidic acid (46 %) is lower than that or erucic acid (83 %) but even then, the amount of brassidic acid found in cardiac lipids (calculated per gram of absorbed fatty acid) after 7 days of feeding is 10 times less than that of erucic acid. Brassidic acid, like erucic acid, can be converted into shorter monoenes (C20:1 and C18:1) since trans-CIS :1 has been found in cardiac phospholipids of rats fed trans-docosenoic acid as the only source of trans-acid in the diet.

The separation of phospholipid classes from human heart was achieved in two steps by high performance liquid chromatography (HPLC) using a silica column with an ultraviolet spectromonitor at 206 nm. A complete partitioning of phosphatidylcholines (PC), phosphatidylethanolamines (PE), phosphatidylinositols (PI), phosphatidylserines (PS), cardiolipins (CL), lysophosphatidylcholines (LPC) and sphingomyelins (Sph) was obtained for further analysis.

Fifty-six male Wistar SPF rats were fed a diet containing low erucic acid rapeseed (LEAR) oil (15% by weight) as the only source of lipids for 18 wk. Lipid parameters (fatty acid composition and contents of lipid classes) and the occurrence and severity of focal lesions were both determined on the heart of each animal. Four groups were constituted according to the severity of cardiac lesions. Statistical analyses were applied to the data to find a relationship between the lipid parameters and the severity of heart lesions. None of the measured parameters (heart contents of neutral lipids, total phospholipids, phosphatidylcholine, phosphatidylethanolamine, diphosphatidylglycerol, sphingomyelin and fatty acid composition of each phospholipid class) appeared to be related with the grading of the lesions. Therefore, we failed to find a direct support for the assumption that heart lesions, induced by LEAR oil, are mediated by changes in the lipid and/or fatty acid composition of heart membranes. However, this hypothesis can not be discarded.