The influence of dietary fatty acid composition on N-ethyl-Nnitrosourea-induced mammary tumour incidence in the rat and on the composition of inositol- and ethanolamine-phospholipids of normal and tumour mammary tissue

This study has investigated the influence of dietary fatty acid composition on mammary tumour incidence in N-ethyl-N-nitrosourea (ENU)-treated rats and has compared the susceptibility to dietary fatty acid modification of the membrane phospholipids phosphatidyliuositol (PI) and phosphatidylethanolamine (PE) from normal and tumour tissue of rat mammary gland. The incidence of mammary tumours was significantly lower in fish oil- (29%), compared with olive oil- (75%; P < 0.04) but not maize oil- (63%; P < 0.1) fed animals. No differences in PI fatty acid composition were found in normal or tumour tissue between rats fed on maize oil, olive oil or fish oil in diets from weaning. When normal and tumour tissue PI fatty acids were compared, significantly higher amounts of stearic acid (18:O) were found in tumour than normal tissue in rats given olive oil (P < 0.05). A similar trend was found in animals fed on maize oil, although differences between normal and tumour tissue did not reach a level of statistical significance (P < 0.1). In mammary PE, maize oil-fed control animals had significantly higher levels of linoleic acid (18:2n-6) than either olive oil- or fish oil-fed animals (P < 0.05, both cases) and levels of arachidonic acid were also higher in maize oil- compared with fish oil-fed animals (P < 0.05). In tumourbearing animals no differences in PE fatty acid composition were found between the three dietary groups. When normal and tumour tissue PE fatty acids were compared, significantly lower amounts of liuoleic acid (18:2n-6; P < 0.01) and significantly greater amounts of arachidonic acid (20:4n-6; P < 0.05) were found in tumour than normal tissue of rats fed on maize oil. The present study shows that the fatty acid composition of PI from both normal and tumour tissue of the mammary gland is resistant to dietary fatty acid modification. The PE fraction is more susceptible to dietary modification and in this fraction there is evidence of increased conversion of linoleic acid to arachidonic acid in tumour compared with normal tissue. Lower tumour incidence rates in rats given fish oils may in part be due to alteration in prostanoid metabolism secondary to displacement of arachidonic acid by eicosapentaenoic acid, but PE rather than PI would appear to be the most likely locus for diet-induced alteration in prostanoid synthesis in this tissue. Effects of dietary fatty acids other than on the balance of n-6 and n-3 fatty acids, and on prostanoid metabolism, should also be considered. The significance of increased stearic acid content of PI in tumours of olive oil-fed animals and the possible influence of dietary fatty acids on the capacity for stearic acid accumulation requires further study.

Salmon consumption during pregnancy alters fatty acid composition and secretory IgA concentration in human breast milk

Fish oil supplementation during pregnancy alters breast milk composition, but there is little information about the impact of oily fish consumption. We determined whether increased salmon consumption during pregnancy alters breast milk fatty acid composition and immune factors. Women (n = 123) who rarely ate oily fish were randomly assigned to consume their habitual diet or to consume 2 portions of farmed salmon per week from 20 wk of pregnancy until delivery. The salmon provided 3.45 g long-chain (LC) (n-3) PUFA/wk. Breast milk fatty acid composition and immune factors [soluble CD14, transforming growth factor-b (TGFb)1, TGFb2, and secretory IgA] were analyzed at 1, 5, 14, and 28 d postpartum (PP). Breast milk from the salmon group had higher proportions of EPA (80%), docosapentaenoic acid (30%), and DHA (90%) on d 5 PP compared with controls (P < 0.01). The LC (n-6) PUFA:LC (n-3) PUFA ratio was lower for the salmon group on all days of PP sampling (P < 0.004), although individual (n-6) PUFA proportions, including arachidonic acid, did not differ. All breast milk immune factors decreased between d 1 and 28 PP (P < 0.001). Breast milk secretory IgA (sIgA) was lower in the salmon group (d 1–28 PP; P = 0.006). Salmon consumption during pregnancy, at the current recommended intakes, increases the LC (n-3) PUFA concentration of breast milk in early lactation, thus improving the supply of these important fatty acids to the breast-fed neonate. The consequence of the lower breast milk concentration of sIgA in the salmon group is not clear.

Immune factors and fatty acid composition in human milk from river/lake, coastal and inland regions of China

Breast milk fatty acid composition may be affected by maternal diet during gestation and lactation. The influence of dietary and breast milk fatty acids on breast milk immune factors is poorly defined. We determined the fatty acid composition and immune factor concentrations of breast milk from women residing in river & lake, coastal, and inland regions of China, which differ in their consumption of lean fish and oily fish. Breast milk samples were collected on days 3 to 5 (colostrum), 14 and 28 post-partum and analysed for soluble CD14 (sCD14), transforming growth factor (TGF)-β1, TGF-β2, secretory immunoglobulin A (sIgA) and fatty acids. The fatty acid composition of breast milk differed between regions and with time post-partum. The concentrations of all four immune factors in breast milk decreased over time, with sCD14, sIgA and TGF-β1 being highest in colostrum in the river & lake region. Breast milk DHA and arachidonic acid (AA) were positively associated, and γ-linolenic acid and EPA negatively associated, with the concentrations of each of the four immune factors. In conclusion, breast milk fatty acids and immune factors differ between regions in China characterised by different patterns of fish consumption and change during the course of lactation. A higher breast milk DHA and AA concentration is associated with higher concentrations of immune factors in breast milk, suggesting a role for these fatty acids in promoting gastrointestinal and immune maturation of the infant.

Dietary conjugated linoleic acid differentially alters fatty acid composition and increases conjugated linoleic acid content in porcine adipose tissue

Conjugated linoleic acids (CLA) have been shown to decrease body fat content in pigs. It is possible that feeding pigs diets rich in CLA may increase carcass lipid CLA to levels that could provide health benefits when included as a part of a healthy diet. Therefore, the aim of the present study was to determine whether dietary CLA supplementation has any effect on the fatty acid composition of subcutaneous and intramuscular adipose tissue in pigs. Thirty-five female cross bred (Large White X Landrace) pigs (initial weight 57·2 kg and initial P2 back fat 11·5 mm) were used in the present study. Pigs were housed individually and randomly allocated to one of six dietary treatments (0·00, 1·25, 2·50, 5·00, 7·50 and 10·00 g CLA55 (55 g CLA isomers/100 g total fatty acids; Natural Lipids Ltd, Hovdebygda, Norway)/kg)
and fed their respective diets for 8 weeks. Twelve CLA isomers in the diet and in pig tissue lipids were separated by Agþ-HPLC. CLA was incorporated at fivefold higher levels in subcutaneous fat as compared with intramuscular fat and in a dose-dependant manner. Overall, the transfer efficiency of CLA was maximized at 5·00 g CLA55/kg. However, there was clear selectivity in the uptake or incorporation of cis,trans-9,11 isomer over the trans,cis-10,12 isomer. In general, CLA supplementation produced significant changes in skeletal muscle and adipose tissue fatty acid composition, indicating that dietary CLA had a potent affect on lipid transport and metabolism in vivo. Significant increases in myristic, palmitic and palmitoleic acids and a reduction in arachidonic acid were observed, suggesting an alteration in
activity of Δ5-, Δ6- and Δ9-desaturases in pig adipose tissue. In conclusion, feeding pigs diets supplemented with CLA increases carcass lipid CLA, but also results in changes in the fatty acid profile in pig fat that could potentially outweigh the benefits of CLA.

The last five amino acid residues at the C-terminus of PRK1 /KKN is essential for full lipid responsiveness

PRK1/PKN is a member of the protein kinase C (PKC) superfamily of serine/threonine protein kinases. Despite its important role as a RhoA effector, limited information is available regarding how this kinase is regulated. We show here that the last seven amino acid residues at the C-terminus is dispensable for the catalytic activity of PRK1 but is critical for the in vivo stability of this kinase. Surprisingly, the intact hydrophobic motif in PRK1 is dispensable for 3-phosphoinositide-dependent kinase-1 (PDK-1) binding and phosphorylation of the activation loop, as the PRK1-Δ940 mutant lacking the last two residues of the hydrophobic motif and the last 5 residues at the C-terminus interacts with PDK-1 in vivo and has a similar specific activity as the wild-type protein. We also found that the last four amino acid residues at the C-terminus of PRK1 is critical for the full lipid responsiveness as the PRK1-Δ942 deletion mutant is no longer activated by arachidonic acid. Our data suggest that the very C-terminus in PRK1 is critically involved in the control of the catalytic activity and activation by lipids. Since this very C-terminal segment is the least conserved among members of the PKC superfamily, it would be a promising target for isozyme-specific pharmaceutical interventions.

Up-regulated Desaturase and Elongase Gene Expression Promoted Accumulation of Polyunsaturated Fatty Acid (PUFA) but Not Long-Chain PUFA in Lates calcarifer, a Tropical Euryhaline Fish, Fed a Stearidonic Acid- and γ-Linoleic Acid-Enriched Diet

The limited activity of Δ6 fatty acid desaturase (FAD6) on α-linolenic (ALA, 18:3n-3) and linoleic (LA, 18:2n-6) acids in marine fish alters the long-chain (≥C₂₀) polyunsaturated fatty acid (LC-PUFA) concentration in fish muscle and liver when vegetable oils replace fish oil (FO) in aquafeeds. Echium oil (EO), rich in stearidonic acid (SDA, 18:4n-3) and γ-linoleic acid (GLA, 18:3n-6), may enhance the biosynthesis of n-3 and n-6 LC-PUFA by bypassing the rate-limiting FAD6 step. Nutritional and environmental modulation of the mechanisms in LC-PUFA biosynthesis was examined in barramundi, Lates calcarifer, a tropical euryhaline fish. Juveniles were maintained in either freshwater or seawater and fed different dietary LC-PUFA precursors present in EO or rapeseed oil (RO) and compared with FO. After 8 weeks, growth of fish fed EO was slower compared to the FO and RO treatments. Irrespective of salinity, expression of the FAD6 and elongase was up-regulated in fish fed EO and RO diets, but did not lead to significant accumulation of LC-PUFA in the neutral lipid of fish tissues as occurred in the FO treatment. However, significant concentrations of eicosapentaenoic acid (EPA, 20:5n-3) and arachidonic acid (ARA, 20:4n-6), but not docosahexaenoic acid (DHA, 22:6n-3), appeared in liver and, to a lesser extent, in muscle of fish fed EO with marked increases in the phospholipid fraction. Fish in the EO treatment had higher EPA and ARA in their liver phospholipids than fish fed FO. Endogenous conversion of dietary precursors into neutral lipid LC-PUFA appears to be limited by factors other than the initial rate-limiting step. In contrast, phospholipid LC-PUFA had higher biosynthesis, or selective retention, in barramundi fed EO rather than RO.

Dietary repletion with ω3 fatty acid or with COX inhibition reverses cognitive effects in F3 ω3 fatty-acid-deficient mice

Dietary deficiency of ω3 fatty acid during development leads to impaired cognitive function. However, the effects of multiple generations of ω3 fatty-acid deficiency on cognitive impairment remain unclear. In addition, we sought to test the hypothesis that the cognitive impairments of ω3 fatty-acid-deficient mice are mediated through the arachidonic acid-cyclooxygenase (COX) pathway. To address these issues, C57BL/6J mice were bred for 3 generations and fed diets either deficient (DEF) or sufficient (SUF) in ω3 fatty acids. At postnatal day 21, the F3 offspring remained on the dam's diet or were switched to the opposite diet, creating 4 groups. In addition, 2 groups that remained on the dam's diet were treated with a COX inhibitor. At 19 wk of age, spatial-recognition memory was tested on a Y-maze. Results showed that 16 wk of SUF diet reversed the cognitive impairment of F3 DEF mice. However, 16 wk of ω3 fatty-acid-deficient diet impaired the cognitive performance of the F3 SUF mice, which did not differ from that of the F3 DEF mice. These findings suggest that the cognitive deficits after multigenerational maintenance on ω3 fatty-acid-deficient diet are not any greater than are those after deficiency during a single generation. In addition, treatment with a COX inhibitor prevented spatial-recognition deficits in F3 DEF mice. Therefore, cognitive impairment due to dietary ω3 fatty-acid deficiency appears to be mediated by the arachidonic acid-COX pathway and can be prevented by 16 wk of dietary repletion with ω3 fatty acids or COX inhibition.

Effects of different dietary lipid sources on the survival, growth, and fatty acid composition of South American catfish, Pseudoplatystoma fasciatum, Surubim, juveniles

The present study examines the effect of four semi-purified diets (casein-gelatin based) where the source of fatty acids was free (esterified) oleic acid and linoleic acid (LA) (LOA diet), linseed and olive oil (predominantly LA and linolenic acid) (LO diet), cod liver oil (rich in highly unsaturated fatty acids) (CLO diet), and soybean lecithin (phospholipids; mostly LA) (LE diet) on the growth of juvenile South American catfish (surubim, Pseudoplatystoma fasciatum, Pimelodidae) (0.98 +/- 0.04 g individual weight). Fish were fed at a restricted-readjusted feeding rate for 8 wk. At the end of the experiment, LE-diet-fed fish grew significantly larger than those of the other three groups (P < 0.05). Considerable cannibalism was observed in all the treatments. It is suggested that the quantitative growth performance may possibly change under other conditions, with less or no cannibalism. Survival did not differ significantly among the fish fed four different diets. Muscle and liver lipid contents did not vary among dietary treatments (P > 0.05), but whole-body lipid concentrations were affected by dietary treatments. Fish fed LE diet contained significantly lower lipid level than those fed three other diets (P < 0.05). Muscle and liver fatty acid profiles reflected dietary fatty acid composition. Arachidonic acid level was significantly higher in muscle and liver of fish fed LOA and LE diets than in those fed LO and CLO diets. The results suggest that the efficiency of elongation and desaturation of 18C fatty acids depends on the dietary lipid source, and South American catfish has considerable capacity to transform linoleate to arachidonate.

Fatty acid composition of mid-trimester amniotic fluid in women of different ethnicities

Objective: To determine whether the fatty acid composition of mid-trimester amniotic fluid differs by ethnicity and pregnancy outcome. Methods: Fatty acid composition was analyzed by gas chromatography in 198 women undergoing amniocentesis at 15-19 weeks gestation. Cytokine levels were determined by ELISA in a subgroup of 52 subjects. Results: The major fatty acids detected were palmitic acid (31.8%) and stearic acid (31.5%). The n-6 polyunsaturated fatty acids (PUFA), linoleic acid (LA, 18: 2) and arachidonic acid (AA, 20: 4), were 11.3%, while the n-3 PUFA fatty acids, alpha linolenic acid (ALA, 18: 3) and docosahexaenoic acid (DHA, 22: 6), were 3.8% of the total. Palmitic acid was a higher percentage in Asians (40.5%) and Whites (34.5%) than in Blacks (22.2%) and Hispanics (23.7%) (p <= 0.0012). Oleic acid (18:1 n-9) was a higher percentage in Blacks (12.2%) and Hispanics (12.1%) than in Whites (9.2%) or Asians (7.5%) (<= 0.0002). LA and AA were higher in Blacks (9.0%, 5.4%) and Hispanics (8.6%, 4.1%) than in Whites (6.1%, 3.7%) and Asians (5.5%, 2.9%) (p <= 0.0002). DHA did not differ among the ethnic groups or according to pregnancy outcome. A reduced palmitic acid percentage was identified in the six women with preeclampsia (p = 0.0233). Tumor necrosis factor-alpha levels were inversely proportional to the palmitic acid percentage (p = 0.0275) and positively associated with the percentages of stearic (18:0) (p = 0.0132) and oleic (p = 0.0290) acids. Conclusions: Amniotic fluid fatty acid composition differed among the ethnic groups and may influence inflammatory mediator production and susceptibility to preeclampsia.

Validation of a FFQ for estimating omega-3, omega-6 and trans fatty acid intake during pregnancy using mature breast milk and food recalls

BACKGROUND/OBJECTIVES: To assess the performance of a food frequency questionnaire (FFQ) for estimating omega-3, omega-6 and trans fatty acid intake during pregnancy. Moreover, we determined whether the fatty acid composition of mature breast milk represents a valuable biomarker for fatty acid intake during pregnancy. SUBJECTS/METHODS: A prospective study in 41 pregnant women, aged 18-35 years, was conducted. Food intake during pregnancy was evaluated by three 24-h recalls (24 hR), and 2 FFQ. The fatty acid composition of mature breast milk was determined by gas chromatography. The method of triads and joint classification between quartiles of intake were applied. RESULTS: The FFQ was accurate for estimating docosahexanoic (DHA), linoleic and total omega-6 fatty acids according to validity coefficients. Higher agreements (>70%) into the same or adjacent quartiles between the dietary methods were found for alpha-linolenic, total omega-3, linoleic and trans fatty acid intake. High validity coefficients for eicosapentanoic (EPA) and DHA acids of human milk were found (0.61 and 0.73, respectively), and the method was adequate for categorizing the intake of alpha-linolenic, total omega-3 and trans fatty acids compared with FFQ estimates, and for arachidonic acid and trans fatty acids compared with food recall estimates, during pregnancy. CONCLUSIONS: The FFQ was an accurate tool for categorizing alpha-linolenic, total omega-3 and trans fatty acid intake. According to the validity coefficients observed, the FFQ accurately estimated DHA, linoleic and total omega-6 fatty acids and the composition of mature breast milk was shown to be a suitable biomarker for EPA and DHA fatty acid intake during pregnancy.

Exploration of the Antiplatelet Activity Profile of Betulinic Acid on Human Platelets

Betulinic acid, a natural pentacyclic triterpene acid, presents a diverse mode of biological actions including antiretroviral, antibacterial, antimalarial, and anti-inflammatory activities. The potency of betulinic acid as an inhibitor of human platelet activation was evaluated, and its antiplatelet profile against in vitro platelet aggregation, induced by several platelet agonists (adenosine diphosphate, thrombin receptor activator peptide-14, and arachidonic acid), was explored. Flow cytometric analysis was performed to examine the effect of betulinic acid on P-selectin membrane expression and PAC-1 binding to activated platelets. Betulinic acid potently inhibits platelet aggregation and also reduced PAC-1 binding and the membrane expression of P-selectin. Principal component analysis was used to screen, on the chemical property space, for potential common pharmacophores of betulinic acid with approved antithrombotic drugs. A common pharmacophore was defined between the NMR-derived structure of betulinic acid and prostacyclin agonists (PGI2), and the importance of its carboxylate group in its antiplatelet activity was determined. The present results indicate that betulinic acid has potential use as an antithrombotic compound and suggest that the mechanism underlying the antiplatelet effects of betulinic acid is similar to that of the PGI2 receptor agonists, a hypothesis that deserves further investigation.

The effect of ploidy on the fatty acid profile during the reproductive cycle of female rainbow trout (Oncorhynchus mykiss)

Rainbow trout Oncorhynchus mykiss triploids are regularly produced in fish farms to improve growth because the triploid females do not develop ovaries during the reproductive cycle. In this study, the tissue fatty acid allocations in triploid and diploid females were compared during the reproductive cycle to determine whether the ploidy influences the fatty acid profile of fish produced in aquaculture. The ovaries, liver, and white muscle fatty acid contents of diploid and triploid females were analyzed during the reproductive cycle. Diploid females tend to accumulate more polyunsaturated fatty acids than triploids during some phases of the reproductive cycle, and this profile was compensated by an increase in saturated and monounsaturated fatty acids in triploid females. Arachidonic acid (C20:4n6) was the main n6 polyunsaturated fatty acid in the ovaries of diploid females during the most advanced phases of the reproductive cycle, and docosahexaenoic acid (C22:6n3) was the main n3 polyunsaturated fatty acid. In triploid females, the percentage of both of these polyunsaturated fatty acids was lower than in diploid females during the most advanced phases of the reproductive cycle. In general, the lack of ovary development altered the hepatic synthesis of some fatty acids, mainly monounsaturated and polyunsaturated fatty acids, decreasing the content of the main fatty acids in the white muscle and, consequently, the mobilization of these specific fatty acids to the ovaries.

Immunomodulatory lipids in plants: plant fatty acid amides and the human endocannabinoid system

Since the discovery that endogenous lipid mediators show similar cannabimimetic effects as phytocannabinoids from CANNABIS SATIVA, our knowledge about the endocannabinoid system has rapidly expanded. Today, endocannabinoid action is known to be involved in various diseases, including inflammation and pain. As a consequence, the G-protein coupled cannabinoid receptors, endocannabinoid transport, as well as endocannabinoid metabolizing enzymes represent targets to block or enhance cannabinoid receptor-mediated signalling for therapeutic intervention. Based on the finding that certain endocannabinoid-like fatty acid N-alkylamides from purple coneflower ( ECHINACEA spp.) potently activate CB2 cannabinoid receptors we have focused our interest on plant fatty acid amides (FAAs) and their overall cannabinomodulatory effects. Certain FAAs are also able to partially inhibit the action of fatty acid amide hydrolase (FAAH), which controls the breakdown of endocannabinoids. Intriguingly, plants lack CB receptors and do not synthesize endocannabinoids, but express FAAH homologues capable of metabolizing plant endogenous N-acylethanolamines (NAEs). While the site of action of these NAEs in plants is unknown, endogenous NAEs and arachidonic acid glycerols in animals interact with distinct physiological lipid receptors, including cannabinoid receptors. There is increasing evidence that also plant FAAs other than NAEs can pharmacologically modulate the action of these endogenous lipid signals. The interference of plant FAAs with the animal endocannabinoid system could thus be a fortunate evolutionary cross point with yet unexplored therapeutic potential.