Liver Phospholipid Fatty Acid Research Articles

Liver phospholipid fatty acid composition in response to chronic high-fat diets

Liver phospholipid fatty acid composition depends on the dietary lipid intake and the efficiency of hepatic enzymatic activity. Our study aimed to simultaneously investigate the liver phospholipid fatty acid composition in response to chronic linseed, palm, or sunflower oil diets. We used adult female C57/BL6 mice and randomly divided them into control and three groups treated with 25 % dietary oils. Prior to treatment, we analyzed the fatty acid profiles in dietary oils and hepatocytes and, after 100 days, the fatty acid composition in the liver using gas-liquid chromatography. Linseed oil treatment elevated alpha-linolenic, eicosapentaenoic, and docosapentaenoic acids and reduced arachidonic and docosatetraenoic acids, consequently lowering the n-6/n-3 ratio. Palm oil treatment increased linoleic acid and decreased docosahexaenoic acid, contributing to an elevated n-6/n-3 ratio. Sunflower oil treatment elevated total monounsaturated fatty acids by increasing palmitoleic, oleic, and vaccenic acids. The estimated activity of Δ9 desaturase was significantly elevated in the sunflower oil group, while Δ5 desaturase was the highest, and Δ6 desaturase was the lowest after the linseed oil diet. Our findings demonstrate that chronic consumption of linseed, palm, or sunflower oil alters the distribution of liver phospholipid fatty acids differently. Sunflower oil diet elevated total monounsaturated fatty acids, proposing potential benefits for liver tissue health. Considering these outcomes, a substantial recommendation emerges to elevate linseed oil intake, recognized as the principal ALA source, thereby aiding in reducing the n-6/n-3 ratio. Moreover, modifying dietary habits to incorporate specific vegetable oils in daily consumption could substantially enhance overall health.

Protein-Energy Malnutrition during Gestation and Lactation in Rats Affects Growth Rate, Brain Development and Essential Fatty Acid Metabolism

The influence of feeding a low protein diet to rat dams during gestation and lactation on lipid metabolism in pups was studied. Wistar rats were fed 5, 10, 15 and 25% dietary protein during gestation and lactation. Pup growth was monitored until weaning, and brain weight, protein concentration, proteolipid concentration and total lipid phosphorus concentration of brain were analyzed. The levels of fatty acids in dam milk as well as in pup liver phospholipids and brain prosphatidylcholine and phosphatidylethanolamine were determined. The progressive deprivation of maternal dietary protein produced a reduction in the total saturated fatty acid concentration of dam milk and an increment in the concentration of nonmetabolized linoleic acid. Pup body and brain weights as well as proteolipid, protein and total lipid phosphorus concentrations in brain were reduced in proportion to the degree of dietary protein deficiency. The products:precursor ratio of (n-6) fatty acids in liver phospholipids revealed an impairment in the elongation-desaturation pathway due to maternal protein deficiency. Both (n-6) and (n-3) polyunsaturated fatty acids within brain phosphatidylethanolamine were decreased by reduced maternal dietary protein intake, whereas only the linoleic acid-derived products were similarly affected in the corresponding phosphatidylcholine fraction. These results demonstrate the widespread and profound deleterious effects of low protein levels of maternal diet on the growth rate, brain development and fatty acid metabolism of rat pups.

Effects of constant and diel cyclic temperatures on the liver and intestinal phospholipid fatty acid composition in rainbow trout Oncorhynchus mykiss during seawater acclimation

BackgroundRainbow trout is an economically important fish in aquaculture and is a model species in environmental physiology. Despite earlier research on the seawater adaptability of rainbow trout at different temperature regimes, the influence on the liver and intestine in this species is still unknown. Two trials were conducted to investigate the effects of constant and diel cyclic temperatures on phospholipid fatty acid (PLFA) composition in the liver and intestine of rainbow trout during seawater acclimation.ResultsAt the end of growth trial 1, fish at 9 and 12.5 °C showed significantly higher ratios of unsaturated to saturated (U/S) and unsaturation index (UI) than those at 16 °C in liver and intestine phospholipids. After day 1 of seawater acclimation, the U/S, UI, and average chain length (ACL) of liver and intestinal phospholipids in fish at 16 °C significantly increased. Two weeks after seawater acclimation, the liver and intestinal PLFA composition adapted to salinity changes. In trial 2, significantly higher U/S, UI, and ACL were found in intestinal phospholipids at 13 ± 2 °C. On the first day after seawater acclimation, UI and ACL in liver phospholipids significantly increased at 13 °C, while fish at 13 ± 2 °C showed significantly decreased U/S, UI, and ACL in the intestine. At the end of growth trial 2, liver PLFA compositions were stable, whereas intestinal PLFA at 13 and 13 ± 1 °C showed significantly decreased U/S, UI, and ACL. A two-way analysis of variance and principal component analysis revealed significant effects of different constant temperatures, seawater acclimation, and their interaction on the liver and intestinal phospholipids, a significant effect of diel cyclic temperature on intestinal phospholipids, and the effects of seawater acclimation and its interaction with diel cyclic temperature on liver phospholipids.ConclusionTemperatures of 9 and 12.5 °C could elevate membrane fluidity and thickness in the liver and intestine of rainbow trout in freshwater, whereas no significant effects were found with diel temperature variations. After seawater acclimation, constant and diel cyclic temperatures significantly influenced the membrane fluidity and thickness of the liver and intestine. Compared with constant temperature, diel temperature variation (13 ± 2 °C) can enhance the adaptability of rainbow trout during seawater acclimation.

НОРМАЛІЗАЦІЯ ФІТОПРЕПАРАТОМ «КВЕРТУЛІН» ОБМІНУ ЕСЕНЦІАЛЬНИХ ЖИРНИХ КИСЛОТ ФОФСОЛІПІДІВ ПЕЧІНКИ ЩУРІВ, ЯКІ ОТРИМУВАЛИ ПАЛЬМОВУ ОЛІЮ НА ТЛІ ДИСБІОЗУ

Keywords: liver, phospholipids, essential fatty acids, palm oil, dysbiosis, herbal medicine. Aim. To study the effect of the phytopreparation kvertulin on the processes of biosynthesis of PUFA of liver phospholipids in rats treated with palm oil against the background of dysbiosis. Methods. Rats consumed a fat-free diet (group 1), a diet with 15 % palm oil (group 2), a diet with 15 % palm oil on the background of experimental dysbiosis (group 3) and a diet with 15 % palm oil on background of dysbiosis + kvertulin. The duration of the experiment is 40 days. The content of fatty acids in liver phospholipids was determined by gas chromatography. The ratio of the PUFA content was used to calculate the “activity” of ω-3-desaturase, the intensity of synthesis of arachidonic acid, and the intensity of synthesis of docosahexaenoic acid. Results: In rats of the 3rd group, which received palm oil against the background of dysbiosis, there was a decrease in the content of ω-3 PUFA, an increase in the ratio of ω-6 / ω-3 PUFA, and a decrease in the “activity” of ω-3-desaturase. In rats of the 4th group, which received kvertulin, the content of PUFA was completely restored and the “activity” of enzymes of their biosynthesis was normalized. Conclusion. The use of the phytopreparation kvertulin normalizes the endogenous biosynthesis of PUFA of liver phospholipids in rats consuming palm oil against the background of dysbiosis.

Liver phospholipids fatty acids composition in response to different types of diets in rats of both sexes

BackgroundDietary intake influence changes in fatty acids (FA) profiles in liver which plays a central role in fatty acid metabolism, triacylglycerol synthesis and energy homeostasis. We investigated the effects of 4-weeks treatment with milk- and fish-based diet, on plasma biochemical parameters and FA composition of liver phospholipids (PL) in rats of both sexes.MethodsAdult, 4 months old, Wistar rats of both sexes, were fed with different types of diets: standard, milk-based and fish-based, during 4 weeks. Analytical characterization of different foods was done. Biochemical parameters in plasma were determined. Fatty acid composition was analyzed by gas-chromatography. Statistical significance of FA levels was tested with two-way analysis of variance (ANOVA) using the sex of animals and treatment (type of diet) as factors on logarithmic or trigonometric transformed data.ResultsOur results showed that both, milk- and fish-based diet, changed the composition and ratio of rat liver phospholipids FA, in gender-specific manner. Initially present sex differences appear to be dietary modulated. Although, applied diets changed the ratio of total saturated fatty acids (SFA), monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA), and effects were gender specific. Milk-based diet lowered SFA and elevated MUFA in males and increased PUFA in females vs. standard diet. The same diet decreased n-3, increased n-6 and n-6/n-3 ratio in males. Fish-based diet increased n-3, decreased n-6 and n-6/n-3 ratio vs. standard and milk-based diet in females. However, the ratio of individual FA in liver PL was also dietary-influenced, but with gender specific manner. While in females fish-based diet decreased AA (arachidonic acid) increased level of EPA (eicosapentaenoic acid), DPA (docosapentaenoic acid) and DHA (docosahexaenoic acid), the same diet elevated only DHA levels in males.ConclusionGender related variations in FA composition of rat liver PL were observed, and results have shown that those initial differences could be significantly modulated by the type of diet. Furthermore, the modulatory effects of milk- and fish-based diets on liver phospholipids FA profiles appeared to be sex-specific.

Effects of Aronia melanocarpa juice on plasma and liver phospholipid fatty acid composition in Wistar rats

Abstract A nutritional placebo-controlled study was performed in Wistar rats in order to investigate the effects of 5-weeks aronia juice consumption towards fatty acid (FA) composition of phospholipids in the plasma and liver, as well as plasma glucose (Glu) and cholesterol levels. The animals were divided into 3 groups of 8 animals each, and randomized to receive either the full polyphenol dose of Aronia melanocarpa juice (AMJ), 4 times less polyphenol dose (¼-AMJ) or polyphenol-lacking placebo beverage (PLB). Each group of 8 male adult Wistar rats received the liquid ad libitum. AMJ decreased the levels of low-density lipoprotein (LDL) (P < 0.05) vs. PLB. AMJ increased dihomo-γ-linoleic acid (DGLA, 20:3n-6) (P < 0.05) and decreased arachidonic acid content (AA, 20:4n-6) (P < 0.05) vs. PLB in liver phospholipids. AMJ significantly increased monounsaturated fatty acids (MUFA) levels both in the liver (P < 0.05) and plasma (P < 0.05). Both aronia juice doses elevated the levels of beneficial n-3 polyunsaturated fatty acids (PUFA) in the plasma and liver. There was a dose-dependent, significant increase (P < 0.001) in cis-vaccenic acid (VA, 18:1n-7) in phospholipids in the plasma and liver. Our results indicate favorable effects of aronia juice intake on lipid parameters in Wistar rats. These findings suggest the potential of aronia dietary intake in cardiometabolic diseases primary prevention strategies in the human population.

Streptozotocin‐Induced Diabetes Partially Attenuates the Effects of a High‐Fat Diet on Liver and Brain Fatty Acid Composition in Mice

The current study addresses the effects of a high-fat diet on liver and brain fatty acid compositions and the interaction of that diet with diabetes in a type 1 mouse model. Adult, male, normal and streptozotocin-induced diabetic C57BL/6 mice were fed standard (14%kcal from fat) or high-fat (54%kcal from fat, hydrogenated vegetable shortening and corn oil) diets for 8weeks. Liver and whole brain total phospholipid fatty acid compositions were then determined by TLC/GC. In the liver of non-diabetic mice, the high-fat diet increased the percentages of 18:1n-9, 20:4n-6, and 22:5n-6 and decreased 18:2n-6 and 22:6n-3. Diabetes increased 16:0 in liver, and decreased 18:1n-7 and 20:4n-6. The effects of the high-fat diet on liver phospholipids in diabetic mice were similar to those in non-diabetic mice, or were of smaller magnitude. In the brain, the high-fat diet increased 18:0 and 20:4n-6 of non-diabetic, but not diabetic mice. Brain 22:5n-6 acid was increased by the high-fat diet in both non-diabetic and diabetic mice, but this increase was smaller in diabetic mice. Diabetes alone did not alter the percentage of any individual fatty acid in brain. This indicates that the effects of a high-fat diet on liver and brain phospholipid fatty acid compositions are partially attenuated by concomitant hyperglycemia with hypoinsulinemia.

Menhaden oil, but not safflower or soybean oil, aids in restoring the polyunsaturated fatty acid profile in the novel delta-6-desaturase null mouse

BackgroundPolyunsaturated fatty acids (PUFA) have diverse biological effects, from promoting inflammation to preventing cancer and heart disease. Growing evidence suggests that individual PUFA may have independent effects in health and disease. The individual roles of the two essential PUFA, linoleic acid (LA) and α-linolenic acid (ALA), have been difficult to discern from the actions of their highly unsaturated fatty acid (HUFA) downstream metabolites. This issue has recently been addressed through the development of the Δ-6 desaturase knock out (D6KO) mouse, which lacks the rate limiting Δ-6 desaturase enzyme and therefore cannot metabolize LA or ALA. However, a potential confounder in this model is the production of novel Δ-5 desaturase (D5D) derived fatty acids when D6KO mice are fed diets containing LA and ALA, but void of arachidonic acid.ObjectiveThe aim of the present study was to characterize how the D6KO model differentially responds to diets containing the essential n-6 and n-3 PUFA, and whether the direct provision of downstream HUFA can rescue the phenotype and prevent the production of D5D fatty acids.MethodologyLiver and serum phospholipid (PL) fatty acid composition was examined in D6KO and wild type mice fed i) 10% safflower oil diet (SF, LA rich) ii) 10% soy diet (SO, LA+ALA) or iii) 3% menhaden oil +7% SF diet (MD, HUFA rich) for 28 days (n = 3-7/group).ResultsNovel D5D fatty acids were found in liver PL of D6KO fed SF or SO-fed mice, but differed in the type of D5D fatty acid depending on diet. Conversely, MD-fed D6KO mice had a liver PL fatty acid profile similar to wild-type mice.ConclusionsThrough careful consideration of the dietary fatty acid composition, and especially the HUFA content in order to prevent the synthesis of D5D fatty acids, the D6KO model has the potential to elucidate the independent biological and health effects of the parent n-6 and n-3 fatty acids, LA and ALA.

Effects of n–3 Supplementation on Plasma and Liver Phospholipid Fatty Acids Profile in Aged Wistar Rats

The effects of fish oil supplementation in Wistar rats are focused on cardiovascular, endocrine, metabolic and antioxidant status changes. We determined plasma and liver phospholipid fatty acids (FAs) status and plasma lipid concentrations in aged Wistar rats. Our results showed differences in plasma and liver FAs profiles as well as plasma chlolesterol (CHOL), triglicerides (TG), high density lipoproteins (HDL), low density lipoproteins (LDL), CHOL/HDL ratio (risk factor for atherosclerosis) and LDL/HDL ratio (risk for cardiovascular diseases) between treated and control group of animals. In fish oil treated group there were statistically significant changes in FAs profile in increasing linoleic acid (LA), dihomo-γ linoleic acid, eicopentanoic acid (EPA) and docosapentaenoic acid (DPA) and decreasing in arachidonic acid (AA) concentration. Also, liver phospholipids FAs results showed increasing concentrations of vascenic acid, LA, EPA, and DPA and decreasing concentration of AA after supplementation of fish oil compared to control group. However, concentrations of CHOL, LDL and non HDL concentrations decreased while HDL increased in fish oil group. CHOL/HDL, LDL/HDL ratios decreased. These findings suggest that long term treatment of fish oil in aged Wistar rats can be beneficial in decreasing LDL, and decreasing risk factors for developing atherosclerosis and cardiovascular diseases. (doi: 10.5562/cca1751)

The Polyunsaturated Fatty Acid Composition of Hepatic and Plasma Lipids Differ by Both Sex and Dietary Fat Intake in Rats1–3

In rats and humans, females have higher liver and/or plasma docosahexaenoic acid (DHA) content than males. We hypothesized that the effect of variation in total fat or essential fatty acid intakes on liver and plasma fatty acid composition would differ between sexes. Rats were fed a low-fat soybean oil (LFS), high-fat soybean oil (HFS), or high-fat linseed oil (HFL) diet for 20 d. There were significant sex differences in LFS rats in proportions of (n-3) and (n-6) fatty acids in plasma and liver contingent on lipid class. Significant diet × sex interactions were observed for eicosapentaenoic acid (EPA), DHA, and arachidonic acid (AA) status. HFL females had a higher proportion of EPA in plasma and liver phosphatidylcholine (PC), DHA in liver triacylglycerol (TAG), and AA in plasma PC than HFS and LFS females. These findings show that the effect of varying dietary fat intake on (n-3) and (n-6) long-chain PUFA (LCPUFA) status is modified by sex. Liver phospholipid and TAG fatty acid product:substrate ratios suggested greater Δ6 desaturase (Δ6D) activity in females than in males. The HFL diet induced higher Δ6D mRNA expression compared with the LFS or HFS diets and HFL females had 10% higher expression of Δ6D mRNA than HFL males. Together, these findings show that sex is an important determinant of the effect of variations in fat and fatty acid intake on LCPUFA status, which may have implications for recommendations for fat and fatty acid intake in humans.

Differential incorporation of dietary conjugated linolenic and linoleic acids into milk lipids and liver phospholipids in lactating and suckling rats

Interest in health benefits of conjugated fatty acids is growing. The present study compared the incorporation pattern of dietary conjugated linolenic acids (CLnA) into milk with that of conjugated linoleic acids (CLA). Lactating Sprague-Dawley rats (Day 1) were divided into five groups fed the control diet ( n=4) or one of four experimental diets supplemented with 1–2% CLA or CLnA mixture ( n=8 each). Supplementation of 1% and 2% CLA led to enrichment of 4.17% and 8.57% CLA, respectively, while supplementation of 1% and 2% CLnA resulted in enrichment of only 0.98% and 1.71% CLnA in the milk lipids, demonstrating the transfer of CLnA from maternal diet to milk was discriminated. When the lactating rats were given a diet containing a CLnA mixture of 9t,11t,13t-, 9c,11t,13t- and 9c,11t,13c-CLnA isomers, two CLA isomers, namely, 9t,11t (0.59–0.90%) and 9c,11t (1.21–1.96%), were found in the milk, suggesting that three CLnA isomers were Δ-13 saturated. Dietary CLnA at 1–2% had no effect on liver phospholipid (PL) fatty acid composition of both maternal and suckling rats, whereas dietary CLA increased docosahexaenoic acid ( 4c,7c,10c,13c,16c,19c-22:6) and palmitic acid (16:0) proportionally in the PL of maternal rats, but it suppressed 16:0 in the PL of suckling rats. It is concluded that maternal rats incorporate CLnA isomers into milk differently from that of CLA isomers. Most interesting is that maternal rats can metabolically convert CLnA to CLA.

Rapid lipid enrichment in ω3 fatty acids: Cause-to-effect relationships

The bolus intravenous administration of a novel medium-chain triglyceride:fish oil emulsion to second generation rats depleted in long-chain polyunsaturated omega3 fatty acids was recently found to enrich within 60 min the content of both plasma and liver lipids in such omega3 fatty acids, this coinciding with correction of the perturbation in liver triglyceride fatty acid content and profile otherwise prevailing in these rats. The present report draws attention to cause-to-effect relationships between changes in liver phospholipid and triglyceride fatty acid content and/or pattern operative under these experimental conditions.

Sex, but not maternal protein or folic acid intake, determines the fatty acid composition of hepatic phospholipids, but not of triacylglycerol, in adult rats

The aim of the study was to investigate whether the protein and folic acid content of the maternal diet and the sex of the offspring alter the polyunsaturated fatty acid content of hepatic phospholipids and triacylglycerol (TAG). Pregnant rats were fed diets containing 18% or 9% protein with either 1 or 5 mg/kg folic acid. Maternal diet did not alter hepatic lipid composition in the adult offspring. Data from each maternal dietary group were combined and reanalysed. The proportion of 18:0, 20:4n-6 and 22:6n-3 in liver phospholipids was higher in females than in males, while hepatic TAG composition did not differ between sexes. Δ5 Desaturase expression was higher in females than in males. Neither Δ5 nor Δ6 desaturase expression was related to polyunsaturated fatty acid concentrations. These results suggest that sex differences in liver phospholipid fatty acid composition may reflect primary differences in the specificity of phospholipid biosynthesis.

Diet (n-3) Polyunsaturated Fatty Acid Content and Parity Affect Liver and Erythrocyte Phospholipid Fatty Acid Composition in Female Rats 3

The fatty acid composition of membrane phospholipids affects the physicochemical properties of the membrane and thus influences cell function. In this study, the effects of 1–4 sequential pregnancies on the phospholipid fatty acid compositions of the maternal liver and erythrocytes were determined in female rats fed diets containing α-linolenic acid (ALA), ALA and preformed docosahexaenoic acid (DHA; ALA+DHA), or minimal ALA (low ALA). Virgin females, fed the diets for commensurate durations, served as a control for reproduction. Liver and erythrocyte total phospholipid compositions were determined at weaning by TLC/GC. In both tissues, significant main effects of diet and reproductive status were detected for many fatty acids, but a significant interaction of diet, reproductive status, and duration of treatment (no. of reproductive cycles or equivalent time period for virgins) was detected only for DHA, 22:6(n-3). Primiparous dams fed the ALA and low ALA diet had decreased liver DHA content of 31% and 74%, respectively, compared with virgin females fed the ALA diet. Liver DHA did not decrease further after additional reproductive cycles. Liver DHA content was unchanged in parous dams fed the ALA+DHA diet, but virgin females fed this diet exhibited a 50% increase in liver DHA after 13 wk of treatment. Changes in erythrocyte DHA were of similar magnitude and time course to those observed in liver, suggesting that this tissue may serve as a marker for liver DHA status.

Rapid changes in liver lipid composition and pancreatic islet K+ handling and secretory behaviour provoked by the intravenous administration of a medium-chain triglyceride:fish oil emulsion to long-chain polyunsaturated ω3 fatty acid-depleted rats

Second generation rats depleted in long-chain polyunsaturated omega3 fatty acids are currently used as an animal model for the insufficient dietary supply of such fatty acids often prevailing in Western populations. The present study deals mainly with the effects of a novel medium-chain triglyceride: fish oil emulsion (MCT:FO), as compared to a control medium-chain triglyceride:olive oil emulsion (MCT: OO), administered as an intravenous bolus to the omega3-depleted rats 60-120 min before sacrifice upon selected biochemical and biophysical variables. The major findings consisted of a severe decrease of the omega3 fatty acid content of liver lipids in non-injected omega3-depleted rats and its partial correction after injection of the MCT:FO emulsion. The omega3-depleted rats also displayed liver steatosis, increased incorporation of long-chain polyunsaturated omega6 fatty acids in liver phospholipids and increased activity of liver Delta9-desaturase. As judged from the effects of ouabain upon 86Rb net uptake by isolated pancreatic islets, the activity of Na+,K+-ATPase was virtually abolished in the omega3-depleted rats. The latter defect was corrected by prior intravenous injection of the MCT:FO emulsion, this coinciding with suppression of the excessive secretory response to a number of insulin secretagogues otherwise observed in the islets of omega3-depleted rats injected or not with the MCT:OO emulsion.

Brain phospholipid and triglyceride fatty acid content and pattern in Type 1 and Type 2 diabetic rats

The liver phospholipid and triglyceride content and/or fatty acid pattern differ(s) not solely in normal versus diabetic rats, but also in distinct rat models of diabetes mellitus. The present study reveals that a comparable situation prevails in the brain. Fed and overnight fasted female normal rats (N) and Goto-Kakizaki rats (GK), as well as fed rats rendered diabetic by a prior injection 3 days before sacrifice of streptozotocin (STZ) were examined. The brain phospholipid content, expressed as milligrams of fatty acids per gram wet weight, was comparable in all groups of rats, with an overall mean value of 31.2 ± 0.8 ( n = 22). The GK rats differed from N and STZ rats by lower C18:0/C18:1ω9 and C18:2ω6/C18:3ω6 ratios and a lower C20:5ω3 content of brain phospholipids. The total amount of fatty acids in triglycerides was 7–8 times higher in GK than N and STZ rats. The GK rats differed from N and STZ rats by lower C16:0/C16:1ω7, C18:0/C18:1ω9 and (C16:0 + C16:1ω7)/(C18:0 + C18:1ω9) ratios in triglycerides. These findings extend to the brain, the knowledge of alterations in phospholipid and triglyceride content and/or fatty acid pattern in GK rats, as compared to N or STZ rats. The former rats indeed displayed: (i) an apparently increased activity of Δ9- and Δ6-desaturases, as suggested by the phospholipid measurements, and a decreased C20:5ω3 content in such phospholipids; (ii) a dramatic increase in brain triglyceride content; and (iii) an increased activity of Δ9-desaturase, as well as elongase, as judged from the triglyceride data.

Changes in Liver Fads2 expression and Phospholipid Fatty Acids in Mice with Hyperhomocysteinemia

Homocysteine is metabolically linked to methylation reactions through the methionine cycle and we have previously shown that hyperhomocysteinemia (HHcy) is accompanied by reduced tissue methylation capacity and altered DNA methylation. Phospholipids are substrates for methylation reactions with phosphatidylcholine (PC) produced following methylation of phosphatidylethanolamine (PE). PC and PE are integral membrane lipids in the liver and we hypothesize that some of the pathological effects of HHcy may be related to changes in PC and PE metabolism. The goal of the present study was to determine the effect of HHcy on liver phospholipids, phospholipid fatty acids and transcripts for Fads2, which functions to desaturate 18:2n-6 and 18:3n-3 to 20:4n-6 and 22:6n-3, respectively. Mice heterozygous for disruption of the gene for cystathionine-β-synthase (Cbs+/−) and C57BL/6 mice (Cbs+/+) were fed a control diet or a high methionine/low folate diet to induce HHcy (HH diet) for 8–12 months. We found a higher percentage of PE (32.0±0.6 vs 26.4±0.5, p<0.001) and lower percentage of PC (41.0±1.1 vs 45.6±0.3, p<0.01) in liver phospholipids of Cbs +/−mice fed the HH diet with HHcy (95±12μmol/L) than Cbs+/+ mice fed the control diet. This was accompanied by lower (p<0.01) 20:4n-6 in PC and PE, higher (p<0.01) 22:6n-3 in PE, and lower (p<0.05) levels of Fads2 transcripts in liver from Cbs+/− fed the HH diet than Cbs+/+ mice fed the control diet. These findings are the first to show altered liver phospholipid fatty acids and Fads2 transcripts in a mouse model of HHcy and suggest a role for changes in phospholipid fatty acid metabolism in the pathology of HHcy.

Effect of Ethanol and Thermally Oxidized Sunflower Oil Ingestion on Phospholipid Fatty Acid Composition of Rat Liver: Protective Role of Cuminum cyminum L.

Aim: The current study was undertaken to assess the effect of ethanol and thermally oxidized sunflower oil ingestion on liver phospholipid fatty acids and the protective role of Cuminum cyminum L. Methods: Ethanol was administered at a level of 20% and thermally oxidized sunflower oil at a level of 15% for 45 days. C. cyminum was administered at a dosage of 250 mg/kg body weight for 45 days. We investigated the changes in the liver phospholipid fatty acid composition. Results: Ethanol and thermally oxidized sunflower oil administration modifies the fatty acid composition and the analysis of fatty acids showed that there was a significant increase in the concentrations of 16:0, 16:1, 18:0, 18:1 and 18:2, whereas the concentration of 20:4 was significantly decreased. The concentrations of 16:0, 16:1, 18:0, 18:1 and 20:4 were near normal in cumin-treated rats. Conclusion: The present investigation shows that cumin prevents the changes in the composition of fatty acids, which were produced by ethanol and thermally oxidized oil.

Effect of linseed oil supplementation on concentrations of (n‐3) polyunsaturated fatty acids in liver phospholipids of rats fed diets containing either an oil rich in conjugated linoleic acids, sunflower oil or high‐oleic acid sunflower oil

This study investigated the metabolism of alpha-linolenic acid and the formation of eicosanoids in rats fed diets with three different dietary fats (30 g/kg diet): either a conjugated linoleic acid (CLA) preparation with a high concentration of cis-9, trans-11 CLA (32.2 g/100 g) and trans-10, cis-12 CLA (33.3 g/100 g) and a low concentration of linoleic acid (0.5 g/100 g), sunflower oil (SFO) with a high concentration of linoleic acid or high-oleic acid sunflower oil (HO-SFO) with a high concentration of oleic acid. Basal diets with those oils were fed for 4 weeks. In the fifth week, the same diets supplemented with 50 g of linseed oil/kg as a source of alpha-linolenic acid were fed. To study the effect of the oils on the metabolism of alpha-linolenic acid, the amounts of individual (n-3) polyunsaturated fatty acids (PUFA) in liver phospholipids (phosphatidyl choline and phosphatidyl ethanolamine) were determined; to study the effect on eicosanoid formation, the concentrations of various two-series eicosanoids in liver and plasma, the activity of the secretory phospholipase A2 and the relative mRNA concentrations of cyclooxygenases-1 and 2 in the liver were measured. Rats fed the CLA diets had the highest concentrations of long chain (n-3) PUFA deriving from delta6, delta5 and 14-desaturation of alpha-linolenic acid in liver phospholipids; rats fed the SFO diet had the lowest concentrations of those fatty acids. The concentration of arachidonic acid in liver phospholipids and the concentrations of eicosanoids in liver and plasma were lowest in rats fed the CLA diet and highest in the rats fed the SFO diet. Moreover, rats fed the CLA diet had a higher gene expression of delta6-desaturase in the liver than the other two groups of rats. The results show that feeding the CLA oil reduced the formation of arachidonic acid and eicosanoids but enhanced the formation of long chain (n-3) PUFA and their incorporation into tissue lipids when compared with feeding SFO or HO-SFO.

Enteral nutrition with stearidonic acid increases incorporation of antiinflammatory N-3 fatty acids in liver phospholipids in the rat

We have shown that an enteral nutrition formula containing eicosa-pentaenoic acid (20:5n-3; EPA) provided beneficial antiinflammatory effects in critically ill patients with acute lung injury. The use of diets enriched with stearidonic acid (18:4n-3; SDA) may provide a novel means to increase EPA content in tissue phospholipids and to provide the health benefits typically associated with n-3 fatty acids from fish oil. There is little known about the effects of increased consumption of SDA on tissue phospholipid fatty acid composition. We examined whether diets supplemented with SDA can be used as a precursor to increase EPA content in liver phospholipids and to determine the effectiveness of SDA in increasing tissue EPA content as compared with dietary EPA in rats. Male Long--Evans rats ( n = 10) were randomly divided into three dietary groups and fed a modified US-17 diet providing 200 kcal/kg/day and containing either 2% oleic acid (OA, 18:1 n-9) ( n = 4), 1% EPA /1% OA ( n = 3), or 1% SDA/1% OA ( n = 3) for 2 weeks. Dietary fatty acid composition was controlled by substituting the ethyl esters of EPA and SDA for OA; thus changes in phospholipid fatty acid composition would be the result of dietary changes of these fatty acids. The fatty acid compositions (mol %) of liver phospholipids were determined by gas chromatography. There was a small reduction, although not significant, in AA content with EPA and SDA as compared with OA. SDA resulted in an increase in EPA content in liver phospholipids that was approximately 50% of that for EPA. There was a smaller increase in tissue DPA content with SDA than EPA as compared with OA. There was no significant increase in DHA content with either EPA or SDA as compared with OA. These results indicate that dietary SDA can be used to increase EPA content in liver phospholipids and the relative effectiveness of SDA conversion to EPA and incorporation into tissue phospholipids was equivalent to one-half of dietary EPA. TABLE—ABSTRACT P77 Fatty acid OA EPA SDA 20:4 n-6 (AA) 28.3 ± 1.02 a 25.1 ± 0.42 a 26.6 ± 0.30 a 20:5 n-3 (EPA) 0.02 ± 0.06 a 1.21 ± 0.43 b 0.66 ± 0.04 a,b 22:5 n-3 (DPA) 0.16 ± 0.04 a 1.65 ± 0.33 b 1.01 ± 0.04 c 22:6 n-3 (DHA) 6.49 ± 0.26 a 6.39 ± 0.004 a 6.67 ± 0.43 a Note. Values with different superscripts are significantly different ( P ≤ 0.05).