Omega 3 but not omega 6 fatty acids inhibit AP-1 activity and cell transformation in JB6 cells.

Epidemiological and animal-based investigations have indicated that the development of skin cancer is in part associated with poor dietary practices. Lipid content and subsequently the derived fatty acid composition of the diet are believed to play a major role in the development of tumorigenesis. Omega 3 (omega3) fatty acids, including docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), can effectively reduce the risk of skin cancer whereas omega 6 (omega6) fatty acids such as arachidonic acid (AA) reportedly promote risk. To investigate the effects of fatty acids on tumorigenesis, we performed experiments to examine the effects of the omega3 fatty acids EPA and DHA and of the omega6 fatty acid AA on phorbol 12-tetradecanoate 13-acetate (TPA)-induced or epidermal growth factor (EGF)-induced transcription activator protein 1 (AP-1) transactivation and on the subsequent cellular transformation in a mouse epidermal JB6 cell model. DHA treatment resulted in marked inhibition of TPA- and EGF-induced cell transformation by inhibiting AP-1 transactivation. EPA treatment also inhibited TPA-induced AP-1 transactivation and cell transformation but had no effect on EGF-induced transformation. AA treatment had no effect on either TPA- or EGF-induced AP-1 transactivation or transformation, but did abrogate the inhibitory effects of DHA on TPA- or EGF-induced AP-1 transactivation and cell transformation in a dose-dependent manner. The results of this study demonstrate that the inhibitory effects of omega3 fatty acids on tumorigenesis are more significant for DHA than for EPA and are related to an inhibition of AP-1. Similarly, because AA abrogates the beneficial effects of DHA, the dietary ratio of omega6 to omega3 fatty acids may be a significant factor in mediating tumor development.

The slow discovery of the importance of omega 3 essential fatty acids in human health.

Although linoleic and linolenic acids have been known to be necessary for normal growth and dermal function since 1930, the omega 3 essential fatty acids (EFA) have not received much attention until recently. The two families of acids are metabolized by the same enzymes, making them competitive. Gross deficiencies of omega 6 plus omega 3 EFA have been observed in humans, induced by attempts at total parenteral nutrition (TPN) with preparations devoid of lipids. Deficiency of omega 3 acids has been induced by TPN containing high omega 6 and low omega 3 fatty acids. In natural human populations, a wide range of omega 3 and omega 6 proportions have been found, ranging from high omega 3 and low omega 6 content to low omega 3 and high omega 6 content, showing inverse correlation between sigma omega 6 and sigma omega 3. In humans with neuropathy or impairment of the immune system, significant deficits of omega 3 EFA have been measured.

13-phenyltridecanoic acid in seed lipids of some aroids.

Several closely related long-chain omega-phenylalkanoic and omega-phenylalkenoic acids occur in the seed lipids of genera of the subfamily Aroideae of the Araceae. One, 13-phenyltridecanoic acid, is a major component. This is the first report of these acids in plant lipids. Their presence in only one subfamily may indicate that the Araceae is diphyletic.

Effects of the incubation of long-chain polyunsaturated fatty acids on platelet lipids and thromboxane release.

Alterations of dietary lipids have been advocated to manipulate platelet release of thromboxane A2. We studied the effects of incubating platelets with several different polyunsaturated fatty acids on platelet-lipid profile and release of thromboxane A2 in response to platelet stimulation. Porcine platelets were isolated by centrifugation, washed three times in Tyrode's solution, and incubated with fatty acids (500 microM) in Tyrode's solution with albumin. Seven polyunsaturated fatty acids of varying lengths (18-, 20-, and 22-carbon chain) of the omega3 and omega6 families were incubated for 60 min at concentrations of 0, 10, 30, and 100 microM with saturated fatty acids comprising the remainder of the 500 microM fatty acids. The platelets were then stimulated for 5 min with A23187 (30 microM). Indomethacin was added, and the platelets were pelleted. Platelet lipids were extracted in hexane, transesterified and quantified by gas chromatography. Using radioimmunoassay, we measured thromboxane B2, the stable metabolite of thromboxane A2, in the platelets' supernatant. A 1-h incubation in each of the seven polyunsaturated fatty acids had no significant effect on platelet-lipid composition. We found a significant increase in thromboxane B2 production in arachidonic acid (100 microM) incubated platelets (324.0 +/- 63.8% of baseline) that was inhibited by eicosapentaenoic acid (81.0 +/- 26.8%, P < 0.01) and to a lesser extent by dihomogammalinolenic acid (189.8 +/- 28.3%, P < 0.03). We conclude that in altering diets to affect platelet release of thromboxane, the two fatty acids of interest are the 20-carbon chain fatty acids, dihomogammalinolenic acid and eicosapentaenoic acid. The ideal amount of each of these fatty acids to be incorporated entails supraphysiologic but pharmacologically achievable levels of fatty acids in plasma.

Essential fatty acid deficiency and predisposition to lung disease in cystic fibrosis.

UNLABELLED: Essential fatty acid (EFA) deficiency is a predisposing factor for pulmonary infection with Staphylococcus aureus and Pseudomonas aeruginosa, the two major pathogenic microorganisms in cystic fibrosis (CF). OBJECTIVE: The goal of this study was to investigate the essential fatty acid status of CF patients from infancy to 20 years old. MATERIALS AND METHODS: Plasma fatty acid profiles for phospholipid (PL) were determined for cord (n = 6), 4 months (n = 40), 16 months (n = 25), 3 y (n = 8), 5-10 y (n = 10), and 10-20 y (n = 10) aged CF patients and compared to their respective control; cord (n = 22), 1-36 months (n = 38) and adult (n = 100). Significance was established by Student's t-test (p < 0.05). RESULTS: The plasma PL fatty acid profile for all CF patients, except cord, revealed consistent deficiency in omega 3 and omega 6 EFAs. These deficiencies were most marked at infancy and more pronounced for patients with meconium ileus. CONCLUSIONS AND RELEVANCE: EFA deficiency may contribute to the predisposition of CF infants to develop respiratory disease and to the excess cytotoxic activity found in bronchoalveolar lavage fluid at 2 months of age in the majority of screened infants.

Isolation and characterization of rat cholangiocyte vesicles enriched in apical or basolateral plasma membrane domains.

Cholangiocytes, the epithelial cells that line intrahepatic bile ducts, are composed of plasma membranes with discrete apical (lumenal) and basolateral domains. While these domains are thought to contain different transporters, exchangers, channels, and receptors, no methodology currently exists for the isolation of these different membrane compartments. Thus, our aim was to develop a technique to isolated plasma membranes from cholangiocytes enriched in apical or basolateral domains. We isolate a cholangiocyte-enriched population of cells from rats 3 weeks after bile duct ligation (BDL), a maneuver which stimulates selective cholangiocyte proliferation. Using isopycnic centrifugation on linear sucrose gradients, we prepared a mixed cholangiocyte plasma membrane (MCPM) fraction from which we further generated separate apical and basolateral cholangiocyte plasma membrane (ACPM and BCPM, respectively). We characterized these fractions by specific marker enzyme assays, transmission electron microscopy (TEM), lipid analysis, anisotropy measurements, one- and two-dimensional gel electrophoresis, and quantitative immunoblots of the cystic fibrosis transmembrane conductance regulator (CFTR). Marker enzyme assays and TEM revealed that the MCPM fraction was essentially devoid of other organelles but was enriched approximately 70-fold in phosphodiesterase I, a general plasma membrane marker; the ACPM and BCPM were appropriately enriched in the respective apical and basolateral markers. TEM of ACPM and BCPM revealed homogeneous preparations of vesiculated membranes without contamination by other organelles. Lipid analysis, one- and two-dimensional gel electrophoresis, CFTR immunoblots, and anisotropy measurements showed unequivocal differences in lipid and protein composition and in fluidity between the ACPM and BCPM domains.(ABSTRACT TRUNCATED AT 250 WORDS)

Patients with anorexia nervosa demonstrate deficiencies of selected essential fatty acids, compensatory changes in nonessential fatty acids and decreased fluidity of plasma lipids.

The objective of this study was to assess the essential fatty acid status of patients with anorexia nervosa. Blood was collected from eight fasting female anorexia nervosa patients with a mean of 81% ideal body weight. Fatty acid composition of phospholipids, nonesterified fatty acids, triglycerides and cholesteryl esters of plasma were determined by capillary gas chromatography to indicate polyunsaturated fatty acids status compared with 19 healthy female adults < 25 y old. Subjects with anorexia nervosa showed polyunsaturated fatty acid deficiencies in plasma phospholipids different from simple nutritional essential fatty acid deficiency or chronic malnutrition. The phospholipid profile showed significantly lower (n-6) and (n-3) elongation and desaturation products, and elevated short-chain saturated, short-chain monounsaturated, branched-chain and odd-chain fatty acids. These elevations indicate enhancement of biosynthesis of alternative fatty acids that only partially compensated for the loss of polyunsaturated fatty acids in providing membrane "fluidity." Calculated mean melting point of the fatty acids of phospholipids in patients with anorexia nervosa was elevated 7.7 degrees C above normal values. These results demonstrate that patients with anorexia nervosa have deficiencies of selected essential fatty acids, compensatory changes in nonessential fatty acids and decreased fluidity of plasma lipids.

Human subcutaneous adipose tissue shows site-specific differences in fatty acid composition.

Adipose tissue was obtained from six women undergoing liposuction twice at 6-mo intervals. Samples obtained bilaterally from abdomen, inner thigh, and outer thigh had fatty acids quantified by gas chromatography. There were no important differences between sides or over time. The saturates 14:0, 16:0, 18:0, and 20:0 were higher in abdominal adipose than in outer thigh (P < 0.002 for all); 16:1 and 18:1 omega 9 were lower in abdomen vs outer thigh (P < 0.01), whereas 18:1 omega 7 and 20:1 omega 9 were unchanged. Polyunsaturates 18:2 omega 6, 20:3 omega 6, and 20:4 omega 6 were higher in outer thigh than in abdomen (P < 0.06), and inner thigh values were intermediate. These changes in fatty acid composition resulted in lower mean triglyceride melting points from abdomen to inner thigh to outer thigh, and suggest that temperature may influence the selection process determining the variation in adipose fatty acid composition with anatomical location. Because the site-specific differences included essential fatty acids, selective uptake as well as potential differences in in situ fatty acid modification are indicated.

Serum fatty acid profiles in cystic fibrosis patients and their parents.

Fatty acid compositions of the major serum lipid classes from 43 cystic fibrosis (CF) homozygotes (CF patients), 36 obligate heterozygotes (parents of CF patients) and 34 controls were determined by capillary gas chromatography. Fatty acid compositions of the homozygote CF patients were skewed in the direction of relative essential fatty acid deficiency in comparison with the controls. Less pronounced, but similar deviations from normal, were observed in the heterozygotes. Homozygotes with normal fatty acid compositions and heterozygotes with considerably disturbed fatty acid profiles were found.

Diets rich in lean beef increase arachidonic acid and long-chain omega 3 polyunsaturated fatty acid levels in plasma phospholipids.

Diets rich in meat are claimed to contribute to the high tissue arachidonic acid (20:4 omega 6) content in people in Westernized societies, but there are very few direct data to substantiate this assertion. Because meat contains a variety of long-chain polyunsaturated fatty acids (PUFA) that are susceptible to oxidation, we initially examined the effect of cooking on the long-chain PUFA content of beef, and then determined the effect of ingestion of lean beef on the concentration of long-chain PUFA in plasma phospholipids (PL). First, we examined the effect of grilling (5-15 min) and frying (10 min) different cuts of fat-trimmed lean beef on the long-chain PUFA content. Second, we investigated the effect of including 500 g lean beef daily (raw weight) for 4 wk on the fatty acid content and composition of plasma PL in 33 healthy volunteers. This study was part of a larger trial investigating the effect of lean beef on plasma cholesterol levels. In the first two weeks, the subjects ate a very low-fat diet (10% energy) followed by an increase in the dietary fat by 10% each week for the next 2 wk. The added fat consisted of beef fat, or olive oil (as the oil or a margarine) or safflower oil (as the oil or a margarine). This quantity of beef provided 60, 230, 125, 140 and 20 mg/d, respectively, of eicosatrienoic acid (20:3 omega 6), 20:4 omega 6, eicosapentaenoic acid (20:5 omega 3), docosapentaenoic acid (22:5 omega 3) and docosahexaenoic acid (22:6 omega 3).(ABSTRACT TRUNCATED AT 250 WORDS)

Essential fatty acid deficiency profiles in idiopathic immunoglobulin A nephropathy.

The profiles of fatty acids (FAs) of plasma phospholipids (the compartment reflecting the essential FA status of tissue lipids), nonesterified FAs (the precursor pool for autacoid synthesis), urine protein excretion, and glomerular filtration rate were measured before and after supplementation with fish oil in 15 patients with immunoglobulin A nephropathy. In the FA profiles, there was deficient 18:3 omega 3 (alpha-linolenic acid), the parent compound of omega 3 polyunsaturated FA, and deficient chain elongation products of both omega 3 and omega 6 polyunsaturated FAs with replacement by saturated and monounsaturated short-chain, odd-chain, and branched-chain FAs, producing significant loss of omega 3 FA. These alterations indicate nutritional or functional (omega 3) and metabolic (omega 6) deficiencies. Additionally, the mean melting point of the FAs was significantly increased, implying an inherent decrease in cell membrane fluidity. Enhancement of 20: 5 omega 3 (eicosapentaenoic acid) and 22:6 omega 3 (docosahexaenoic acid) and suppression of 20:4 omega 6 (arachidonate) after supplementation with fish oil were accompanied by important decreases in proteinuria and improved glomerular filtration rate. Omega-3 polyunsaturated FAs may favorably influence immunoglobulin A nephropathy through a modulation of the pathologic actions of the omega 6 eicosanoids and other diverse actions on various mediators produced by an initial immune injury.

Myocardial lipid composition in turkeys with dilated cardiomyopathy.

OBJECTIVE: The aim was to determine if reduced heart lipid peroxidation in turkeys with two forms of dilated cardiomyopathy, previously reported, was related to an alteration in the lipid composition of the ventricle. METHODS: Myocardial lipid composition was measured in turkeys with two types of dilated cardiomyopathy. Twenty six turkeys with naturally occurring dilated cardiomyopathy, six with furazolidone induced dilated cardiomyopathy, and 18 age matched control birds were used at 1 day, 9-10 days, and 38-78 days of age. Left ventricular fatty acid composition of the phospholipid, triglyceride, free fatty acid, and cholesterol ester fractions was analysed using gas chromatography. RESULTS: Significant age related changes were identified in the fatty acid composition of the heart. In the phospholipid fraction, linoleic acid (18:2 omega 6) values increased with age, while arachidonic acid values decreased. The saturated to unsaturated fatty acid ratio in control hearts was unchanged as a function of age in the phospholipid fraction. In the triglyceride fraction, however, this ratio decreased substantially between newly hatched and nine day old birds and then markedly increased in two month old controls. There was a striking alteration in the saturated to unsaturated fatty acid ratio in the triglyceride fraction of 2 month old cardiomyopathic birds; this ratio was markedly increased in the furazolidone induced cardiomyopathic turkey hearts (5.14 v 2.79 in controls) and markedly diminished (ie, 0.97 to 1.21) in the spontaneously cardiomyopathic turkeys. A significant increase in myristic (14:0) and decrease in linoleic (18:2 omega 6) acid concentration in the furazolidone group v control and a marked decrease in myristic and increase in linoleic acid concentrations in the spontaneously cardiomyopathic group v controls was present. CONCLUSIONS: (1) There is an age related alteration in the fatty acid composition of control turkey hearts. (2) Previously identified reduced lipid peroxidation in furazolidone induced and spontaneous cardiomyopathy in turkeys does not appear to be related to reduced concentration of polyunsaturated fatty acids. (3) The two forms of dilated cardiomyopathy are associated with markedly disparate alterations in the concentration of polyunsaturated fatty acids in the triglyceride fraction of 1-2 month old turkey hearts. The changes may be related, in part, to the pathogenesis in these two different forms of dilated cardiomyopathy.

Abnormal plasma lipids of patients with Retinitis pigmentosa.

Retinitis pigmentosa (RP) is a hereditary retinal degeneration of unknown etiology, resulting in progressive night blindness, loss of peripheral vision, abnormal retinal pigmentation and reduced electroretinographic response. Docosahexaenoic acid (22:6 omega 3) is found in high concentration in the rod outer segment membranes of the retina. Previous reports of low 22:6 omega 3 in blood lipids or phospholipids in RP patients prompted us to evaluate the complete fatty acid (FA) profiles of plasma phospholipids (PL), cholesteryl esters, triglycerides (TG) and nonesterified fatty acids (NEFA) in ten patients with RP. In the PL fraction, we found significantly depressed levels of 22:6 omega 3, 22:5 omega 3, total omega 3, 22:5 omega 6, 22:4 omega 6 and total omega 6 polyunsaturated FA (PUFA), and elevated total saturated acids. Plasma TG showed normal levels of PUFA, normal total saturated FA and total monounsaturated FA. The NEFA fraction showed significant elevation in total saturated FA with depressed total omega 6 PUFA. Evidence is accumulating mulating that RP is associated with abnormal PUFA and lipid metabolism.

Effects of endotoxin on pigs prefed omega-3 vs. omega-6 fatty acid-enriched diets.

We investigated in a porcine model whether omega-3 fatty acids modify the physiological response to sepsis. For 8 days, 16 male pigs were fed a diet containing 18% fat by weight enriched with either omega-3 or omega-6 fatty acids (FA). A group of six pigs receiving their regular diet served as controls. The omega-3 FA-supplemented pigs had elevated levels of omega-3 FA in their serum-free FA, serum phospholipid (PL), and platelet PL levels compared with either of the other groups. On the ninth day, the unanesthetized pigs were injected with 0.3 mg/kg of endotoxin (Escherichia coli) intravenously. The animals had a significant decrease in their arterial O2 pressure (PaO2) [from 84.4 +/- 6.8 (SD) to 64 +/- 9.4, and from 83.1 +/- 7.2 to 55.9 +/- 6.3 mmHg in the omega-6 FA and regular diet groups, respectively]. The PaO2 did not decrease in the omega-3 FA pigs. The omega-3 FA group had significantly lower pulmonary vascular resistance (541 +/- 205 dyn.s.cm-5) 20 min after endotoxin compared with either the omega-6 FA or regular diet groups (797 +/- 233 and 1,102 +/- 552 dyn.s.cm-5, respectively) and more normal blood pressure compared with the other two groups. Plasma thromboxane (Tx) B2 and 6-ketoprostaglandin F1 alpha (6-keto-PGF1 alpha) levels were lowest in the omega-3 FA diet group and highest in the regular diet group.(ABSTRACT TRUNCATED AT 250 WORDS)

Essential fatty acid status and fluidity of plasma phospholipids in cystic fibrosis infants.

The fatty acid (FA) patterns of cord serum phospholipids (PLs) were examined in 4 cystic fibrosis (CF) newborns, 8 non-CF siblings, and 22 normal control subjects. Plasma from 27 newly diagnosed CF infants and 38 normal infants aged less than 2 y were studied for comparison. CF cord-blood PLs had patterns similar to those of CF siblings and to normal newborns, but the pattern for CF did not shift toward adult patterns during infancy as did patterns for normal infants. CF infants at diagnosis exhibited a deficiency pattern in which 18: 2 omega 6, 20:4 omega 6, 22:4 omega 6, an omega 3 polyunsaturated fatty acids (PUFAs) were significantly subnormal and 18:3 omega 6, total saturated fatty acids, and total monounsaturated fatty acids were significantly elevated compared with normal infants. In PLs in CF infants, although mean chain length of FAs was low, mean melting point was elevated 2.4 degrees C and double-bond index was low (both P less than 0.001), implying a significantly lessened fluidity. Nutritional supplements of both omega 6 and omega 3 PUFAs are cated.

Fatty acid composition of hepatic triglycerides in Reye's syndrome: implications for hepatic desaturase abnormalities.

Serum NEFA profiles in Reye's syndrome are reportedly unique with a disproportionate percent made up of polyunsaturated fatty acids some of which are not ordinarily found in the serum. This pattern is also reflected in the serum triglyceride composition as well. As the liver is probably the sole source of the serum triglyceride in Rye's syndrome because patients are vomiting or in coma, the fatty acid acid composition of the liver triglyceride was examined for insight regarding the lipid abnormalities in this disease. Palmitic acid (16:0) and the sum of all the saturated fatty acids in the liver triglycerides were significantly decreased whereas the sum of the monoenoic fatty acids and the products of delta 9 desaturase activity were increased in Reye's samples. When these data were compared to the fatty acid composition of the serum triglyceride from a separate cohort of Reye's and control subjects, certain inferences regarding hepatic delta 9, delta 6, delta 5, and delta 4 desaturase activities and the elongases can be drawn from the liver and serum triglyceride fatty acid profiles which are unique. Collectively, these data reflect considerable intrahepatic fatty acid desaturation and elongation activity and/or acyl transfer from lipid to lipid of various polyunsaturated fatty acids in Reye's syndrome.

Unusual isomeric polyunsaturated fatty acids in liver phospholipids of rats fed hydrogenated oil.

Linoleic acid (18:2 omega 6) and linolenic acid (18:3 omega 3) are precursors of two series of essential fatty acids (EFA) formed by alternate desaturations and elongations. In EFA deficiency (EFAD), oleic acid (18:1 omega 9) and palmitoleic acid (16:1 omega 7) undergo the same reactions to form polyunsaturated fatty acids (PUFA) of other structures. Partially hydrogenated soybean oil (PHSO) contains isomeric 18:1 acids that can be converted to unusual isomers of 18:2 by liver microsomes. To test whether 18:2, 20:3, and 20:4 of unusual structure occur in phospholipids as a consequence of EFAD or ingestion of PHSO, rats were fed corn oil, an EFA-deficient diet, or PHSO to provide isomeric 18:1 acids. At 2.5 months the phospholipids were isolated from livers and converted to methyl esters, and the 18:2, 20:2, 20:3, and 20:4 fractions were isolated. The 18:2 and 20:2 fractions were ozonized, and, by using a computer solution of simultaneous equations, the structures and proportions of each isomer were calculated. The 20:3 and 20:4 fractions were analyzed by ozonolysis and capillary gas chromatography. When corn oil was fed, the major isomer in each group was 9,12-18:2, 11,14-20:2, 8,11,14-20:3, and 5,8,11,14-20:4. Patterns in EFAD- and PHSO-fed groups were more diverse, with large proportions of unusual isomers. Feeding EFA-deficient diet and PHSO induced measurable amounts of unusual PUFA at each step of the cascade, and these PUFA may compete in metabolism of normal PUFA and are substrates for oxidative formation of autacoids of unknown structures and function.

Deficiency of essential fatty acids and membrane fluidity during pregnancy and lactation.

In a group of 19 normal pregnant women, plasma lipids were extracted, phospholipids were isolated, and the fatty acid (FA) compositions were measured by capillary gas chromatography. Blood samples were taken at 36 wk, at labor, and at 6 wk postpartum. The FA profiles showed deficiencies of omega 6 and omega 3 FA (omega indicating the length of the terminal saturated chain), the latter more severe, at all three times. Mean melting point (MMP) was calculated for each sample as an index of "fluidity" based upon all FA present. MMP varied linearly with total polyunsaturated FA and with double bond index, current measures of "fluidity" and essential FA status. MMP was elevated 9-11 degrees C in plasma phospholipids of women during pregnancy and labor and postpartum. Lactating mothers showed less recovery from the deficiencies than did the nonlactating mothers, but neither approached normal at 6 wk. The changes seen in phospholipid profiles suggest a significant transfer of omega 3 and omega 6 polyunsaturated FA from the mother to the fetus. These FA are essential for normal fetal growth and development; their relative deficiency in maternal circulation suggests that dietary supplementation may be indicated.