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PubMed1997

Differential effects of polyunsaturated fatty acids on chemosensitivity of NIH3T3 cells and its transformants.

Polyunsaturated fatty acids (PUFAs) have been suggested, on the basis of animal-model studies, to be related not only to cancer development but also to chemotherapeutic effects. Controversy persists, however, as to which types of PUFAs are beneficial in terms of chemosensitivity. In this study, we used the NIH3T3 cell line and its SIC(sigmoid colon cancer)-oncogene transformants to investigate the effects of PUFAs on the chemosensitivity of non-malignant and malignant cells in terms of cell proliferation. We also determined the fatty-acid composition of cells by high-performance liquid chromatography (HPLC). The results revealed that the sensitivity of SIC transformants to mitomycin C (MC) was lower than that of NIH3T3 cells cultured in 10% calf-serum DMEM without PUFA supplementation. When cells were cultured in DMEM supplemented with eicosapentaenoic acid (EPA) at a concentration (2 micrograms/ml) that does not influence cell proliferation, the sensitivity of SIC transformants to MC increased, whereas that of NIH3T3 cells decreased in comparison with the sensitivity of cells cultured without PUFA supplementation (p < 0.05). There was no difference between the 2 cell lines in the chemosensitivity of cells cultured in medium supplemented with arachidonic acid (ARA). The SIC transformants contained more stearic acid (C:18) and less lauric acid (C:12) than NIH3T3 cells cultured without PUFA. Culturing the cells in medium supplemented with EPA or ARA modified the cellular fatty-acid composition. EPA caused the relative combined percentage of lauric acid and myristic acid (C:14) in SIC transformants to decrease significantly, and the SIC transformants tended to accumulate additional EPA, in contrast to the NIH3T3 cells. We conclude that the alterations in fatty-acid composition in malignant transformants caused by exogenous EPA differ from those in non-malignant cells, and that these changes account for the increased chemosensitivity of malignant transformants. Although preliminary, these findings imply that EPA specifically enhances the chemosensitivity of malignant cells.

3T3 Cells↗
PubMed2002

Effects of alpha lipoic acid, ascorbic acid-6-palmitate, and fish oil on the glutathione, malonaldehyde, and fatty acids levels in erythrocytes of streptozotocin induced diabetic male rats.

In this research, it has been aimed to evaluate the improvement effects of alpha lipoic acid (ALA), ascorbic acid-6-palmitate (AA6P), fish oil (FO), and their combination (COM) on some biochemical properties in erythrocytes of streptozotocin (STZ)-induced diabetic male rats. According to experimental results, glutathione (GSH) level in erythrocytes decreased in diabetes (P < 0.01), D + ALA, and D + AA6P groups (P < 0.001). Malonaldehyde (MA) level increased in diabetes (P < 0.05), D + FO, and D + COM groups (P < 0.001), but its level in D + AA6P and D + ALA groups was lower in diabetes group (P < 0.01). Total lipid level in diabetes and diabetes plus antioxidant administered groups were higher than control. Total cholesterol level was high in diabetes and D + ALA groups (P < 0.05), but its level reduced in D + FO compared to control and diabetes groups, P < 0.05, < 0.001, respectively. Total triglyceride (TTG) level was high in the D + ALA (P < 0.05) and D + COM (P < 0.001) groups. In contrast, TTG level in blood of diabetes group was higher than diabetes plus antioxidant and FO administered groups (P < 0.001). According to gas chromatography analysis results, while the palmitic acid raised in diabetes group (P < 0.05), stearic acid in D + FO, D + ALA, and diabetes groups was lower than control (P < 0.05), oleic acid reduced in D + COM and D + FO groups, but its level raised in D + AA6P and D + ALA groups (P < 0.01). As the linoleic acid (LA) elevated in ALA + D, D + AA6P, and diabetes groups, linolenic acid level in diabetes, D + AA6P, and D + FO groups was lower than control (P < 0.001). Arachidonic acid (AA) decreased in D + ALA, D+ AA6P, and diabetes groups (P < 0.01), but its level in D + COM and D + FO was higher than control (P < 0.05). Docosahexaenoic acid (DHA) increased in D + AA6P and D + COM (P < 0.05). While the total saturated fatty acid level raised in diabetes group, its level reduced in D + ALA and D + FO groups (P < 0.05). In contrast, total unsaturated fatty acid level in D + ALA and D + FO groups was higher than control (P < 0.05). In conclusion, present data have confirmed that the combination of the ALA, AA6P, and FO have improvement effects on the recycling of GSSG to reduced GSH in erythrocytes of diabetic rats, and in addition to this, oxidative stress was suppressed by ALA and AA6P, and unsaturated fatty acid degree was raised by the effects of ALA and FO.

Animals↗
PubMed1995

Generation and remodeling of phospholipid molecular species in rat hepatocytes.

In order to assess the relationship between de novo phospholipid synthesis and remodeling by deacylation-reacylation, we have pulse-labeled glycerolipids by incubating rat hepatocytes in media containing either [U-14C]glycerol or H218O. Further incubation for up to 2 h in the absence of the labeled substrates and analysis of phosphatidylcholine (PC) and phosphatidylethanolamine (PE) provided information on the remodeling of newly synthesized molecular species by deacylation-reacylation at the sn-1 or sn-2 positions of glycerol. We conclude that de novo synthesis of PC and PE yields primarily four molecular species: 16:0-18:2 (n-6), 16:0-18:1, 16:0-22:6 (n-3), and 18:1-18:2 (n-6). Remodeling occurs in both lipid classes by replacement of the fatty acids at the sn-1 position with stearic acid, 18:0, or at the sn-2 position with arachidonic acid, 20:4 (n-6). A major molecular species of both PC and PE, 18:0-20:4 (n-6), appears to be produced by deacylation-reacylation at both the sn-1 and sn-2 positions and not to be further remodeled. De novo synthesis and remodeling of PC and PE in rat hepatocytes occur at similar rates, involve precursor-product relationships among newly synthesized molecular species, and therefore may be regulated as a single metabolic process.

Acylation↗
PubMed1995

Acylation of the Marburg virus glycoprotein.

The surface protein of Marburg virus (GP) is modified by acylation, as shown by labeling with [3H]myristic and [3H]palmitic acid. Acylation of GP also occurred when it was expressed in insect cells with the baculovirus expression system. Gas chromatographic analyses of the bound fatty acids indicated that exogenously added [3H]myristic acid was partly metabolized to palmitic and stearic acid. To elucidate the nature of the fatty acid bond, [3H]palmitic acid-labeled GP was treated with mercaptoethanol. Since the fatty acids were removed by this treatment, it is concluded that the linkage is of the thioester type. A putative attachment site for thioester-linked fatty acids consisting of two cysteine residues located between the transmembrane anchor and the carboxy-terminal cytoplasmic tail of GP (Cys671 and Cys673) could be identified. Site-directed mutagenesis of these two amino acids to alanine residues clearly demonstrated that both cysteines could serve as acylation sites.

Acylation↗
PubMed2001

Incorporation of dietary linoleic and conjugated linoleic acids and related effects on eggs of laying hens.

In the present study, laying hens received 29 g per kg diet of a preparation containing either 70% linoleic acid (LA) or approximately the same amount of conjugated linoleic acid (CLA) in the control and experimental treatments, respectively. The CLA preparation consisted predominantly of cis-9,trans-11 and trans-10,cis-12 fatty acid isomers as free fatty acids in a ratio of 1:1. The diets were fed for 8 wk to determine the effect of dietary CLA on quality characteristics of eggs. In addition, the fatty acid composition of liver and heart was analyzed. Performance parameters (egg weight, feed efficiency) were not significantly affected by feeding the diets supplemented with CLA. The overall amount of CLA that was incorporated into yolk was 7.95 g CLA/100 g total fatty acids, or approximately 400 mg CLA/egg. The transfer efficiency of the cis-9,trans-11 isomer was higher than that of the trans-10,cis-12 isomer; however, the transfer rate of CLA isomers into yolk and tissues was significantly lower than that of linoleic acid. Dietary CLA increased the concentration of saturated fatty acids in yolk and tissues at the expense of monounsaturated fatty acids. The proportions of myristic, palmitic, and stearic acids in yolk lipids were also changed by dietary CLA. Additionally, long-chain polyunsaturated fatty acids (arachidonic acid and docosahexaenoic acid) were decreased without changing the balance of the n-6/n-3 ratio in egg yolk. The inclusion of CLA in layer diets altered the shape of the yolk and various egg parameters (albumen height, foam index, and yolk index). The results of this study indicate that CLA induces various changes in lipid and fatty acid metabolism of laying hens and affects quality characteristics of eggs.

Animal Feed↗
PubMed1989

Fatty acid composition of amastigote and trypomastigote forms of Trypanosoma cruzi.

The fatty acid composition of total lipids from trypomastigote and amastigote forms of Trypanosoma cruzi and of Vero cells before and after parasite infection were analyzed by gas-liquid chromatography and mass spectrometry. Even-numbered, saturated, monoenoic and polyenoic acids ranging from C-12 to C-18 were characterized in both T. cruzi development stages. Significant changes in the fatty acid composition occurred during the T. cruzi life cycle. Oleic and linoleic acids were prominent in trypomastigote forms, whereas palmitic acid was the major fatty acid of amastigotes. Other differences include higher stearic acid and lower palmitoleic and linolenic acid levels as well as the absence of lauric acid in amastigotes as compared with trypomastigote forms. The fatty acid pattern of Vero cells before T. cruzi infection as compared with that after infection showed mostly qualitative differences. Linoleic and linolenic acids were observed only in T. cruzi infected cells.

Animals↗
PubMed1994

Acylation of proteins of the archaebacteria Halobacterium cutirubrum and Methanobacterium thermoautotrophicum.

Although the membrane lipids of extremely halophilic archaebacteria are exclusively derived from diphytanylglycerol diether, which is non-acylated, small amounts of fatty acids have been detected in these organisms. These fatty acids are formed by the action of a fatty acid synthase (FAS), shown to be present in the extreme halophile Halobacterium cutirubrum, despite the fact that only a fraction of the activity of FAS remains at the high salt concentration (> 4 M) present in the cytoplasm. It has now been demonstrated that fatty acids do not occur in lipid-bound form but largely in the form of acylated proteins in the red membrane of H. cutirubrum. In contrast, the bacteriorhodopsin of the purple membrane of this extreme halophile does not appear to be acylated. The thermophilic methanogen, Methanobacterium thermoautotrophicum had a much higher fatty acid synthase activity than the extreme halophile, and the synthase activity of the methanogen was optimal under its normal (anaerobic) growth conditions. The methanogen also utilized the resulting fatty acids to acylate its membrane proteins. The major fatty acids in both organisms were palmitic and stearic acids with small amounts of myristic and 18:1 acids, and these were bound to protein through both ester and amide linkages.

Acylation↗
PubMed1995

Influence of cell culture conditions on diet-induced changes in lymphocyte fatty acid composition.

The effect of a range of dietary lipids on the fatty acid composition and membrane fluidity of lymphocytes was investigated. The effects of subsequent culture of these lymphocytes in medium containing autologous serum, foetal calf serum or a serum-free supplement were assessed; this was considered important, since many studies investigating the effects of dietary lipid manipulation on immune function have used protocols involving a variety of cell culture conditions when performing tests of immune function. Weanling Lewis rats were fed for 10 weeks on a low-fat (LF; 20 g/kg) diet or on high fat diets containing 200 g/kg of either hydrogenated coconut oil (HCO), olive oil (OO), safflower oil (SO), evening primrose oil (EPO) or menhaden oil (MO). The fatty acid composition of the phospholipid fractions of lymphocytes from the spleen was altered by dietary lipid manipulation, whereas the fatty acid composition of thymic lymphocytes was not modified significantly. In general, the changes in the fatty acid composition of spleen lymphocytes reflected the fatty acid composition of the diets themselves. Despite the considerable changes in the fatty acid composition of lymphocytes from spleen, dietary lipid manipulation had no effect on the plasma membrane fluidity of these cells. Culturing lymphocytes in autologous serum allowed some, but not all, of the diet-induced changes in fatty acid composition to be maintained. The effects of dietary lipid manipulation were totally reversed when lymphocytes were cultured in FCS. Culturing lymphocytes in serum-free medium not only reversed any effects of dietary manipulation, but also markedly increased the appearance of palmitoleic and oleic acids, at the expense of palmitic and stearic acids, suggesting activation of the delta 9 desaturase when these cells were cultured in the absence of exogenous lipid. This study suggests that cell culture conditions have significant influence on the changes in lymphocyte fatty acid composition brought about by dietary lipid manipulation and may therefore influence the outcome of functional tests.

Animals↗
PubMed1996

Characterization of the sphingomyelin content of isolated pancreatic islets. Evaluation of the role of sphingomyelin hydrolysis in the action of interleukin-1 to induce islet overproduction of nitric oxide.

Inflammatory cytokines may participate in the destruction of pancreatic islets during the pathogenesis of insulin-dependent diabetes mellitus, and the cytokine interleukin-1 (IL-1) strongly inhibits insulin secretion from rat pancreatic islets by a process which involves induction of expression of the inducible isoform of nitric oxide synthase and the overproduction of nitric oxide. The signaling events between IL-1 receptor occupancy and induction of nitric oxide synthase in rat islets involve activation of the transcriptional activator NFkappa B. Because sphingomyelin hydrolysis has been implicated as a signaling process both in NFkappa B activation and in IL-1 action in some cells, we have examined the potential involvement of sphingomyelin hydrolysis in the induction of islet nitric oxide overproduction by IL-1. Rat islet sphingomyelin pools were radiolabeled with [3H]choline, and sphingomyelin was then isolated by normal phase HPLC. Electrospray ionization-mass spectrometric analysis revealed islet sphingomyelin consists of at least 4 distinct molecular species, and the most abundant of them contained sphingosine as the long chain base and a residue of palmitic acid as the fatty acid substituent. Molecular species containing residues of stearic acid and arachidic acid were also observed. Neither interleukin-1 nor tumor necrosis factor-alpha was found to induce hydrolysis of islet sphingomyelin species, and neither an exogenous, cell-permeant ceramide species (N-acetyl-D-sphingosine) nor exogenous sphingomyelinase mimicked or potentiated the effect of IL-1 to increase rat islet nitric oxide generation, as reflected by nitrite production. Similar findings were obtained with RINm5F insulinoma cells and with mouse pancreatic islets. These findings provide the first information on the molecular species of sphingomyelin in pancreatic islets and suggest that sphingomyelin hydrolysis is not involved in the signaling pathway whereby IL-1 induces the overproduction of nitric oxide by pancreatic islets.

Animals↗
PubMed1989

Effect of propranolol on accumulation of NEFA in the ischemic perfused rat heart.

The effect of propranolol on the accumulation of non-esterified fatty acids (NEFA) in the isolated, perfused working rat heart was investigated. Ischemia was induced by lowering the afterload pressure to 0 mm Hg for 20 min and for reperfusion, the pressure was raised to the pre-ischemic pressure (60 mm Hg) for 20 min. The heart was frozen for biochemical studies immediately after ischemia or reperfusion. Ischemia decreased mechanical function, increased the levels of palmitoleic, arachidonic and linoleic acids, left oleic, lauric, myristic, palmitic and stearic acids unchanged, decreased the levels of adenosine triphosphate (ATP), creatine phosphate (CrP) and the energy charge potential (ECP), and increased the level of lactate. Propranolol (10(-5) or 3 x 10(-5) M) restored mechanical function and inhibited the changes in NEFA, ATP and ECP caused by ischemia. It is suggested that propranolol inhibits the decrease in mechanical function and high energy phosphates caused by ischemia, and thereby inhibits the accumulation of NEFA, especially of the unsaturated fatty acids such as arachidonic acid, during ischemia.

Animals↗
PubMed1977

Composition of adrenal lipids from some domestic and wild ruminants.

1. Lipids from the whole adrenal glands of the ox and the African buffalo (Syncerus caffer) were extracted and fractionated into neutral and phospholipids. Both species revealed the presence of considerable quantities of cholesterol but only very small quantities of cholesteryl esters. 2. Fatty acids from various fractions of bovine and buffalo adrenal glands were investigated by gas-chromatography. They showed a remarkably low content of higher unsaturated fatty acids and a very high content of stearic acid. 3. Mitochondrial and microsomal fractions were isolated from the adrenal glands of the impala antelope (Aepyceros melampus), their lipids extracted, analyzed and compared with the composition of the mitochondrial lipids from bovine adrenal glands. 4. Subcellular fractions of the bovine and impala adrenal glands contain only very small quantities of esterified cholesterol. Most of the lipid fractions were characterized by the absence of adrenic acid (C22:4 omega 6) and a low content of arachidonic acid.

Adrenal Glands↗
PubMed1998

Mechanisms of amino acid release from the isolated anoxic/reperfused rat heart.

Loss of amino acids into the coronary artery perfusate, which is exacerbated during anoxic stress, may have important implications for the ability of hearts subjected to ischemia or anoxia to recover function during reoxygenation. This work investigates the mechanisms underlying the amino acid efflux. Rat Langendorff heart preparations were used to study amino acid loss into coronary artery perfusates during anoxia or anoxia/reoxygenation sequences. Coronary flow rates, heart rates and intra-aortic pressures were recorded. Changes in myocardial amino acid concentrations were equated with amino acid levels in collected anoxic perfusate. With the exception of taurine, the differences in amino acid levels between normoxic and anoxic hearts were smaller than the amounts lost into the coronary perfusates, indicating ongoing replenishment of most amino acids during the anoxic episode. Fifteen-minute periods of exposure to low oxygen levels (P02 18-20 mmHg) resulted in large percentage increases in perfusate amino acid levels which returned slowly towards control levels upon reoxygenation. Anion channel blockers, anthracene-9-carboxylic acid, furosemide, and 4-acetamido-4-isothiocyanostilbene-2,2'-disulfonic acid (SITS), depressed anoxia-elicited increases in amino acid release. Phospholipase inhibition with quinacrine, 4-bromophenacyl bromide and 7,7-dimethyl-eicosadenoic acid (DEDA) depressed the anoxia-evoked release of amino acids. Combined applications of SITS and DEDA exhibited additive effects, virtually abolishing anoxia-evoked release of all the amino acids. The protein kinase C inhibitor, chelerythrine chloride, and the protein tyrosine kinase inhibitors, genistein and lavendustin A, inhibited anoxia-evoked amino acid release. Polyunsaturated fatty acids, arachidonic and linoleic, reduced anoxia-evoked amino acid release whereas monosaturated (oleic) and saturated (stearic) acids were ineffective. The glutamate transport inhibitor, dihydrokainate, depressed anoxia-evoked glutamate and aspartate release. These results suggest that at least three possible mechanisms for the anoxia-evoked amino acid efflux including (a) diffusional release through volume activated anion channels, (b) leakage across myocyte plasma membranes as a consequence of phospholipase activation and (c) reversal of Na+ dependent high-affinity transporters.

Amino Acids↗
PubMed1997

Effect of dietary flaxseed on fatty acid composition, superoxide, nitric oxide generation and antilisterial activity of peritoneal macrophages from female Sprague-Dawley rats.

The impact of ground flaxseed (FS) or flaxseed meal (FSM) diets on the fatty acid composition and functions of rat peritoneal exudate cells (PEC) was determined. Female weanling Sprague-Dawley rats (10/group) were fed isocaloric AIN-76 diets supplemented with 0.0, 10.0% (w/w) FS or 6.2% (w/w) FSM. At the end of 56-days, rat serum and thioglycollate-elicited PEC were analyzed for total lipid fatty acids. Production of nitric oxide (NO) and superoxide (O2-), Listeria monocytogenes (LM) phagocytic index and antilisterial activity of resident PEC were also assessed. A significant increase in alpha-linolenic (C18:3), eicosapentanoic (C20:5) and docosahexanoic (C22:6) acids, as well as a significant reduction in arachidonic acid (C20:4) was observed in the serum of rats fed 10% FS. Dietary FS caused a significant reduction in palmitic acid (C16:0) and an increase in stearic acid (C18:0) of PEC. Defatted FSM produced a significant increase in long chain fatty acids, which included eicosadienoic acid (C20:2) in PEC and C22:6 in serum. PEC from rats fed 10.0% FS produced significantly less (about 50%) O2- in response to phorbol myristate acetate (PMA), than did PEC from control animals; dietary treatment had no effect on O2- in response to LM. FSM had no impact on the O2- production by PEC in response to PMA or LM. Antilisterial activity of PEC was determined by comparing bacterial uptake after 1 hr with recovery 24 hrs later. Despite comparably equivalent bacterial uptake, few viable intracellular LM were recovered at T = 24 for all test samples, indicating that, regardless of the dietary treatment, PEC were able to handle the in vitro LM infection. This bacterial clearance was accompanied by equivalent NO generation by PEC from each dietary group in response to LM. Summarily, dietary FS produced significant changes in fatty acid composition of serum and PEC, inhibited O2- generation by PEC, and was ineffectual to both NO production by and antilisterial activity of PEC.

Animals↗
PubMed2004

Mitochondrial lipids in Bufo arenarum full-grown oocytes.

Both the content and composition of polar and neutral lipids from the mitochondrial fraction of ovarian full-grown Bufo arenarum oocytes were analysed in the present study. Triacylglycerols (TAG) represent 33% of the total lipids, followed by phosphatidylcholine (PC), free fatty acids (FFA) and phosphatidylethanolamine (PE). Diphosphatidylglycerol (DPG) or cardiolipin, a specific component of the inner mitochondrial membrane, represents about 4% of the total lipid content. Palmitic (16:0) and arachidonic (20:4n6) acids are the most abundant fatty acids in PC and PE, respectively. DPG is enriched in fatty acids with carbon chain lengths of 18, the principal component being linoleic acid. In phosphatidylinositol (PI), 20:4n6 and stearic acid (18:0) represent about 72 mol% of the total acyl group level. The main fatty acids in TAG are linoleic (18:2), oleic (18:1), and palmitic acids. The fatty acid composition of FFA and diacylglycerols (DAG) is similar, 16:0 being the most abundant acyl group. PE is the most unsaturated lipid and sphingomyelin (SM) has the lowest unsaturation index.

Animals↗
PubMed2005

Regional variation in shea butter lipid and triterpene composition in four African countries.

The triacylglycerol, fatty acid, and polycyclic triterpene compositions of shea butter were determined for 150 samples from the sub-Saharan countries of Mali, Burkina Faso, Nigeria, and Uganda. The compositional profiles showed high variability in all three classes of compounds. Shea butter is made up mainly of four triglycerides (TAG) differing in carbon number (CN) by two, starting from CN 50 to CN 56. The greatest source of variation was in the CN 54 TAG. Shea butter is characterized by 16 saturated and unsaturated fatty acids in greatly varying proportion, the major ones being the even homologues in the range of C(16)-C(20). Oleic acid is dominant in Ugandan provenances, whereas stearic acid is dominant in West African shea butter. Acetyl and cinnamyl polycyclic triterpene means for countries ranged from 3.69 to 12.57%, with the highest values found in Nigerian provenances. Statistical comparisons of fat composition show that the geographic distance between shea populations is reflected in the degree of separation of their chemical profiles.

Burkina Faso↗
PubMed1998

Acute effects of dietary fatty acids on the fatty acids of human milk.

Although it is known that the fatty acid profile of human milk is altered by diet, the rapidity with which this occurs has not been addressed. We hypothesized that after absorption the fatty acids of a given meal would be transferred rapidly from the chylomicrons of the blood into human milk. Fourteen lactating women drank six test formulas, each containing a different fat: menhaden oil, herring oil, safflower oil, canola oil, coconut oil, or cocoa butter. The subjects collected a midfeeding milk sample before consuming the breakfast test formula and additional samples at 6, 10, 14, and 24 h and then once daily for 4-7 d. Fatty acids of special interest included eicosapentaenoic and docosahexaenoic acids from menhaden oil, cetoleic acid from herring oil, linoleic acid from safflower oil, linolenic acid from canola oil, lauric acid from coconut oil, and palmitic and stearic acids from cocoa butter. Each of these fatty acids increased significantly in human milk within 6 h of consumption of the test formulas (P < 0.001). Maximum increases occurred 10 h after safflower oil; 14 h after cocoa utter, coconut oil, canola oil, and menhaden oil (eicosapentaenoic acid); and 24 h after herring oil and menhaden oil (docosahexaenoic acid). All of these fatty acids remained significantly elevated in milk (P < 0.05) for 10-24 h, except for docosahexaenoic acid, which remained significantly elevated for 2 d, and eicosapentaenoic acid, which remained elevated for 3 d. These data support the hypothesis that there is a rapid transfer of dietary fatty acids from chylomicrons into human milk.

Adult↗
PubMed1998

Lipoprotein secretion by intestinal Caco-2 cells is affected differently by trans and cis unsaturated fatty acids: effect of carbon chain length and position of the double bond.

The effects of trans fatty acids on intestinal lipoprotein secretion were determined in polarized Caco-2 cells. Palmitic acid (16:0), palmitoleic acid (c-16:1delta9), and palmitelaidic acid (t-16:1delta9), as well as stearic acid (18:0), oleic acid (c-18:1delta9), c-vaccenic acid (c-18:1delta11), elaidic acid (t-18:1delta9), and t-vaccenic acid (t-18:1delta11) were studied. Compared with 18:0 (control), c- and t-18:1delta9 increased triacylglycerol secretion (2.7- and 3.6-fold, respectively) as well as apolipoprotein (apo) B-48 and apo B-100 secretion (both 1.6-fold compared with 18:0); c- and t-18:1delta11 caused a modest 1.7-fold increase in triacylglycerol secretion with no significant effect on secretion of apo B. Thus, the position of the double bond in the 18:1 isomers, but not its geometrical configuration, affected lipoprotein secretion by Caco-2 cells. In contrast, the effects of the geometrical isomers (cis and trans) of C16 fatty acids were not comparable: t-16:1delta9 did not affect triacylglycerol and apo B secretion (compared with 16:0, as control) whereas c-16:1delta9 was a potent stimulator of secretion of triacylglycerol (2.4-fold higher than 16:0), apo B-48 (1.3-fold higher than 16:0), and apo B-100 (1.5-fold higher than 16:0). We conclude that the carbon chain length of fatty acids, as well as the position of double bonds and their stereochemical configuration, are important determinants of the unique effects of various species of dietary trans fatty acids on lipoprotein secretion and composition in Caco-2 cells.

Caco-2 Cells↗
PubMed1993

Effects of edible oils and fatty acids on the formation of mutagenic heterocyclic amines in a model system.

The effects of glycerol, fatty acids and oils on the yield and species of mutagenic heterocyclic amines were studied in a model system. The addition of lipids to the model system did not affect the species of food mutagens formed, but did affect the yield of 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx). When heating creatinine, glycine and glucose dissolved in water, at 180 degrees C for 10 and 30 min, 9 and 18 nmol MeIQx/mmol creatinine were formed respectively. Corresponding figures of MeIQx formed, after addition of various fatty acids or edible oils to the model system, were as follows: oleic acid (9 and 11 nmol MeIQx/mmol creatinine), stearic acid (16 and 19 nmol), linoleic acid (8 and 16 nmol), linolenic acid (5 and 20 nmol), corn oil (10 and 33 nmol) and olive oil (10 and 28 nmol) after heating at 180 degrees C for 10 and 30 min respectively. Addition of corn or olive oil in a model system heated at 180 degrees C for 30 min, almost doubled the yield of MeIQx formed, compared with the amount formed in a model system without fat. This increase was not observed if glycerol or a fatty acid was added to the model system.

Amines↗