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PubMed2004

Enterocyte fatty acid uptake and intestinal fatty acid-binding protein.

This article reviews our current understanding of the uptake of fatty acids by the enterocytes of the intestine. The micellar solubilization of fatty acids by bile salts and the factors regulating that process are discussed. The mechanism of how micellar solubilization of fatty acids promotes the uptake of fatty acids by enterocytes and their relative importance is reviewed. Additionally, discussion of the various fatty acid transporters located at the brush border membrane of the enterocytes is included. Finally, a summary of our current understanding of the function of fatty-acid-binding proteins inside enterocytes is provided.

Animals↗
PubMed2000

Litchi chinensis fatty acid diversity: occurrence of the unusual cyclopropanoic fatty acids.

Litchi chinensis (Sapindaceae) is a tree that originates from China and is cultivated for its sweet fruits all over the world in warm climates. Unusual fatty acids such as cyclopropanoic fatty acids have been identified in the seeds of Litchi. Because of their potential value for industry (as inks, cosmetics, detergents, lubricants, etc.), the variability in the relative levels of unusual fatty acids in the seeds of 28 different Litchi varieties was analysed at two locations (on Réunion Island in the Indian Ocean) and on two different harvest dates. Except for one variety, all the seeds contained cis-9,10-methylene-octadecanoic acid (C(19)CA) at a relative level of 35-48%. The only variety that contained no or only traces of C(19)CA was Groff, seeds of which were significantly much smaller than those from all other varieties.

China↗
PubMed1995

Polyunsaturated fatty acid deficiencies: effects on hepatic plasma membrane fatty acid composition and enzyme activity.

Research on dietary polyunsaturated fatty acids (PUFA), on the activity of 5'nucleotidase and adenylate cyclase are largely contradictory due, mostly, to the absence of adequate control group. In this study; four different diets have been evaluated on the 5'nucleotidase and adenylate cyclase activities in rat liver plasma membranes. Wistar rats were given a semisynthetic diet in which lipids were supplied by 5% of either peanut oil (n-3 PUFA deficient diet), cod liver oil (n-6 PUFA deficient diet) partially hydrogenated palm oil (total PUFA deficient diet) and a mixture of peanut and rapeseed oil (control group). Liver plasma membranes were separated by using a Percoll gradient in a Beckman JA 20 centrifuge. 5'nucleotidase and adenylate cyclase activities were measured in a liquid scintilation detector by following the degradation of 3HAMP (adenosine monophosphate) and production of 3HcAMP (cyclic adenosine monophosphate) respectively. Animals fed the total PUFA deficient diet exhibited significant lower body weight and lower liver weight than did the control group. Low cholesterol concentrations were observed in animals deficient either in n-3 or total PUFA in relation to the control group. All dietary deficiencies studies provoked reduced phospholipid levels. Phosphatidylcholine and phosphatidylethanolamine were not modified whatever the deficiency studied. Phospholipids fatty acid composition was significantly modified by the diets studied. The specific activity of 5'nucleotidase in hepatic plasma membrane was independent of dietary PUFA. The catalytic unit of adenylate cyclase complex in totally deficient animals was augmented. The unit of the enzyme stimulated by the guanydyl imidodiphosphate (GppNHp) in n-3 PUFA deficient animals was augmented and reduced in animals receiving the n-6 PUFA deficient diet. In conclusion, our results show that each dietary PUFA deficiency modifies differently the proportions of phospholipid classes and their fatty acid composition. The mechanisms responsible for these modification remain to be elucidated. However, the phospholipid fatty acid changes did not influence the 5'nucleotidase activity except in the case of extreme excess which concerns more toxicology than nutritional modifications. Finally, the catalytic unit (Forskoline + GDP beta s) of adenylate cyclase complex and the regulatory unit (GppNHp) may be sensitive to alterations in PUFA composition.

5'-Nucleotidase↗
PubMed1999

Impact of processing on formation of trans fatty acids.

Trans fatty acids are formed during hydrogenation which is done to improve the functionality and oxidative stability of oils. Several process conditions affect the content of trans fatty acids in hydrogenated oil. There is conflicting evidence as to whether intake of trans fatty acids, in foods such as margarine, affects the types and levels of cholesterol produced in the blood. Epidemiological studies have shown associated increases in total cholesterol and low density lipoproteins, as well as decreased levels of high density lipo-proteins in the blood. It is unknown whether these effects are related directly to trans fatty acids or to the decrease of unsaturated fatty acids in the diet. This chapter will cover the recent nutritional status of trans fatty acids and the effect of processing on the levels of trans fatty acids in foods.

Adult↗
PubMed1994

Feeding trans fatty acids to rats has no effect on the intestinal uptake of glucose, fatty acids or cholesterol.

Trans fatty acids are produced in the manufacture of margarine, and these hydrogenated fatty acids may have a deleterious effect on the reduction in fasting levels of serum cholesterol anticipated from the feeding of cis polyunsaturated fatty acids. We undertook this study in rats to test the effect of feeding trans fatty acids on the intestinal uptake of glucose, fatty acids and cholesterol. Adult female Wistar rats were fed for 2 weeks semisynthetic, isocaloric diets containing no oleic acid (18:1), cis 18:1 or trans 18:1. There was no difference between the three dietary groups in the animals' food consumption or body weight gain. Rats fed trans 18:1 had an approximately 20% decline in the total weight of the ileum as compared with controls fed no 18:1, and therefore there was also a decline in the percentage of the ileal tissue comprised of mucosa. When comparing rats fed trans 18:1 with those fed cis 18:1 or no 18:1, there was no difference in the uptake of varying concentrations of D-glucose when expressed as nmol.100 mg tissue-1.min-1 or nmol.100 mg mucosal-1.min-1 for jejunum or for ileum. Also, there was no difference in the value of the maximal transport rate (Vmax), Michaelis constant (Km), or the contribution of passive uptake of glucose assessed with L-glucose. There was no diet-associated change in the jejunal or ileal uptake of a medium-chain length fatty acid (lauric acid), a long-chain length saturated fatty acid (palmitic acid), a monounsaturated fatty acid (oleic acid), two polyunsaturated fatty acids (linoleic and linolenic acids), or cholesterol. Thus, we conclude that 2 weeks' feeding of trans fatty acid to rats has no influence on the jejunal or ileal uptake of glucose, fatty acids or cholesterol.

Absorption↗
PubMed1984

Purification of S-acyl fatty acid synthase thioester hydrolase by affinity chromatography with fatty acid synthase attached to Sepharose.

S-Acyl fatty acid synthase thioester hydrolase, the enzyme responsible for release of short-chain fatty acids from fatty acid synthase, was purified to homogeneity in 50-60% yield by a procedure involving affinity chromatography with fatty acid synthase as the affinity ligand attached to Sepharose. This procedure gave a 10- to 12-fold increase in yield over the previously available method.

Animals↗
PubMed1993

Dietary alpha-linolenic acid alters tissue fatty acid composition, but not blood lipids, lipoproteins or coagulation status in humans.

We examined the effect of dietary alpha-linolenic acid (ALA) on the indices of lipid and coagulation status and on the fatty acid composition of serum and peripheral blood mononuclear cell (PBMNC) lipids in ten healthy men (age 21-37 yr) who consumed all their meals at the Western Human Nutrition Research Center for 126 d. There was a stabilization period of 14 d at the start when all 10 subjects consumed the basal diet (BD) containing 23.4 energy percent (en%) fat and two intervention periods of 56 d each. During the first intervention period, 5 subjects consumed the BD containing 23.4 en% fat, and 5 subjects consumed a diet providing 6.3% calories from alpha-linolenic acid [flaxseed oil (FSO) diet containing 28.8 en% fat]. Diets were crossed over between the two groups during the second intervention period. Feeding the FSO diet did not significantly alter serum triglycerides, cholesterol, high-density lipoproteins, low-density lipoproteins, apoprotein A-I and apoprotein B when compared to the corresponding values in the subjects fed the BD, nor was there any effect of the FSO diet on the bleeding time, prothrombin time and partial prothrombin time for these subjects. Feeding the ALA-containing diet did cause a significant increase in ALA concentration in serum (P < 0.001) and PBMNC lipids (P < 0.05). It also caused a significant increase (P < 0.05) in the eicosapentaenoic and docosapentaenoic acid contents of PBMNC lipids, and a decrease (P < 0.01) in linoleic and eicosatrienoic acid contents of serum lipids.(ABSTRACT TRUNCATED AT 250 WORDS)

8,11,14-Eicosatrienoic Acid↗
PubMed1986

Dietary n-3 polyunsaturated fatty acids: modification of rat cardiac lipids and fatty acid composition.

The effects of 5, 10 and 20% dietary menhaden oil (MO) on the composition of heart lipid classes and fatty acids were studied. Male Sprague-Dawley rats were fed ad libitum 0, 5, 10 and 20% MO for 3 wk. The heart phosphoglyceride content and composition and cholesterol were unchanged by dietary MO. A nonlinear dose-response relationship was observed between dietary MO levels and fatty acid compositional changes. Cardiolipin, choline (PC), ethanolamine (PE) and serine/inositol (PS/PI) phosphoglycerides showed an incorporation of n-3 fatty acids, eicosapentaenoic (20:5n-3) and docosahexaenoic (22:6n-3), between the control and 5% MO group, a plateau between the 5 and 10% MO groups and a further increase at the 20% MO level. The initial reduction in 20:4n-6 content remained unchanged as dietary MO increased except in PE where a further reduction was found at the 20% MO level. Dietary MO did not significantly change the 20:4n-6 content in neutral lipids. Linoleic acid content was most resistant to dietary MO removal. The level of 18:2n-6 was significantly lowered in heart PC when rats were fed 10% MO. No significant differences were found in PS/PI. In PE and NL significant differences occurred only when rats were fed 20% MO. The significant fatty acid modifications of heart lipid and PL found between the control and lowest level of dietary MO (5%) suggest that dietary fish oil supplementation in human diets may not be required for this effect.

Animals↗
PubMed1989

Abortive infection of the virulent phage 9NA in a fatty acid auxotroph of Salmonella typhimurium: effect of fatty acid supplementation.

A conditional (temperature sensitive) fatty acid biosynthetic mutant (fabB2) of Salmonella typhimurium does not support the development of the virulent bacteriophage 9NA even at permissive temperature (30 degrees C). A limited amount of phage DNA synthesis takes place at this temperature. When the fatty acid composition of the host membrane is altered by growing the cells at 37 degrees C in the presence of exogenous unsaturated fatty acid, differential expression of phage genes was observed. Phage specific lysozyme is induced when the cultures are supplemented with elaidic, palmitelaidic, linoleic and linolelaidic acids but not with oleic and plamitoleic acids. However, in no case were infective particles produced. Under conditions where no lysozyme is synthesized the infected cells increase in length and become filamentous.

Bacteriophages↗
PubMed2000

The fatty acid transport function of fatty acid-binding proteins.

The intracellular fatty acid-binding proteins (FABPs) comprise a family of 14-15 kDa proteins which bind long-chain fatty acids. A role for FABPs in fatty acid transport has been hypothesized for several decades, and the accumulated indirect and correlative evidence is largely supportive of this proposed function. In recent years, a number of experimental approaches which more directly examine the transport function of FABPs have been taken. These include molecular level in vitro modeling of fatty acid transfer mechanisms, whole cell studies of fatty acid uptake and intracellular transfer following genetic manipulation of FABP type and amount, and an examination of cells and tissues from animals engineered to lack expression of specific FABPs. Collectively, data from these studies have provided strong support for defining the FABPs as fatty acid transport proteins. Further studies are necessary to elucidate the fundamental mechanisms by which cellular fatty acid trafficking is modulated by the FABPs.

Animals↗
PubMed1989

2-Hydroxy fatty acids from marine sponges. 2. The phospholipid fatty acids of the Caribbean sponges Verongula gigantea and Aplysina archeri.

The alpha-hydroxy fatty acids 2-hydroxy-eicosanoic (1) acid, 2-hydroxyheneicosanoic (2) acid, 2-hydroxydocosanoic (3) acid, 2-hydroxytetracosanoic (4) acid, 2-hydroxy-23-methyl-tetracosanoic acid and 2-hydroxypentacosanoic (5) acid were isolated from the Caribbean sponges Verongula gigantea and Aplysina archeri. The very long chain fatty acids 5,9-nonacosadienoic acid (29:2) and 5,9,23-tricontatrienoic acid (30:3) were also identified together with the iso-prenoid fatty acid 3,7,11,15-tetramethylhexadecanoic (phytanic) acid that seems to be common in the Aplysinidae. A. archeri contained an extremely long chain fatty acid tentatively characterized as dotricontaenoic (32:1) acid. These acids were found to occur in phosphatidylserine, phosphatidylinositol, phosphatidylethanolamine, phosphatidylcholine and traces of phosphatidylglycerol.

Animals↗
PubMed1988

Altered phosphoinositide fatty acid composition, mass and metabolism in brain essential fatty acid deficiency.

This study describes the specific alterations in phosphoinositide mass and fatty acid composition observed in brain essential fatty acid deficiency (EFAD). These investigations were motivated by the observation that alterations in volatile anesthetic potency were associated with changes in brain arachidonyl-phosphatidylinositol (PI) content, and were aimed at defining whether EFAD might alter the generation of chemical second messengers via the PI cycle. Analyses of cerebral cortical phosphoinositide mass and fatty acid composition showed that EFAD results in specific and preferential depletion of arachidonate (20:4(n - 6); 5,8,11,14-eicosatetraenoic acid) from cerebral cortical polyphosphoinositides, and that this depletion is reversed by parenteral supplementation with linoleic acid (18:2(n - 6); 9,12-octadecadienoic acid). These analyses also showed that, while phosphoinositides containing 20:3(n - 9) (5,8,11-eicosatrienoic acid) accumulated in EFAD, linoleate supplementation decreased 20:3(n - 9)-PI and 20:3(n - 9)-phosphatidylinositol 4-phosphate (PIP), but resulted in accumulation of 20:3(n - 9)-phosphatidylinositol 4,5-bisphosphate (PIP2). Comparison of the fatty acid composition of brain polyphosphoinositides and 1,2-diacylglycerols between treatment groups showed that diacylglycerols contain a lower molar percentage of 20:3(n - 9) and a higher percentage of arachidonate than the corresponding polyphosphoinositides. The combined results of these studies suggest the existence of fatty acid substrate specificity for the hydrolysis of PIP2 by phospholipase C. The biological relevance of these findings is suggested by a strong correlation between the mass of cerebral cortical arachidonyl-PIP2 and the potency of the anesthetic halothane.

Animals↗
PubMedDate not supplied

[Intensification of the ionophoric effect of polymyxin M by free fatty acids. Dependence of the length of the fatty acid chain].

Mechanisms of potentiation of ionophoric effect of polymyxin M by free fatty acids was studied using measurement of electrical properties of bilayer lipid membranes. Among used unsaturated fatty acids the palmitic acid appeared to be the most effective. The obtained dependence of ionophoric effect of membrane antibiotic on the chain length of the fatty acid may be explained by the existence of the complex of special size appropriate to the membrane thickness. We suppose that free fatty acid and polymyxin M form the ion-conducting structure in lipid bilayer.

Drug Synergism↗
PubMed2000

Is the erythrocyte membrane fatty acid composition a valid index of skeletal muscle membrane fatty acid composition?

Recent studies suggest that insulin sensitivity is related to the fatty acid composition of phospholipids in skeletal muscle (SM) membranes. Since it is difficult to obtain muscle biopsies, it may be useful to have information on the fatty acid composition using more accessible cells such as erythrocytes. This would be possible only if the composition of erythrocyte and muscle membranes are very similar. Since no comparative data are available, we evaluated the phospholipid fatty acid composition of erythrocyte and SM membranes in 16 individuals, 10 nondiabetics (male to female ratio, 4:6; age, 50 +/- 11 years; body mass index, 27 +/- 5 kg/m2; mean +/- SD) and 6 type 2 diabetic patients (male to female ratio, 2:4; age, 64 +/- 5 years; body mass index, 27 +/- 4 kg/m2). All patients underwent abdominal surgery, during which a biopsy of the abdominal rectus muscle (50 to 100 mg) was obtained. Erythrocyte and SM phospholipid fatty acids were extracted and then methylated; the methyl fatty acids were separated and quantified by gas chromatography. Compared with erythrocyte membranes, muscle membranes showed a significantly higher proportion of omega-6 polyunsaturated fatty acid ([PUFA] 43.0% +/- 3.1% v29.7% +/- 1.6%, P < .001) and lower saturated fatty acid ([SFA] 41.1% +/- 1.5% v 43.4% +/- 1.2%, P < .001), monounsaturated fatty acid ([MUFA] 11.5% +/- 1.7% v 20.0% +/- 1.9%, P < .001), and omega-3 PUFA (3.8% +/- 0.6% v 7.4% +/- 1.0%, P < .001). The greatest increase involved linoleic acid (26.9% +/- 2.8% v 10.3% +/- 1.6%, P < .001), whereas lignoceric acid (0.8% +/- 0.2% v 5.0% +/- 0.6%, P < .001) and oleic acid (10.4% +/- 1.6% v 13.5% +/- 1.3%, P < .001) were significantly lower. These results show that erythrocyte and muscle membrane phospholipid fatty acids are significantly different. Therefore, data on SM membranes cannot be extrapolated on the basis of measures of erythrocyte phospholipid fatty acid composition.

Adult↗
PubMed2002

Trans polyunsaturated fatty acids have more adverse effects than saturated fatty acids on the concentration and composition of lipoproteins secreted by human hepatoma HepG2 cells.

The objective of this study was to assess the relative long-term effects of linoleic (cis, cis 18:2), linolelaidic (trans, trans 18:2), and palmitic (16:0) acids on hepatic lipoprotein production in HepG2 cells. All fatty acids increased the mass of triglycerides (TG) in the medium and the incorporation of [(3)H]-glycerol into secreted TG; the increase was more pronounced with linoleic acid than with linolelaidic and palmitic acids. The net accumulation in the medium of apolipoprotein (apo) A-I was not affected by the fatty acids tested and moderate changes in that of apoB resulted in apoB/apoA-I mass ratios of 1.05, 1.27 and 0.86 with linoleic, linolelaidic and palmitic acids, respectively. The incorporation of [(14)C]-acetate into cellular plus secreted total sterols was 9.1%, 33.6% and 17.4% of total [(14)C]-labeled lipids with linoleic, linolelaidic and palmitic acids, respectively. Relative to linoleic acid, palmitic acid, and to a greater extent (P < 0.05) linolelaidic acid, increased the secretion and cellular accumulation of [(14)C]-labeled free cholesterol (FC) and cholesteryl esters and decreased those of TG and phospholipids (PL). Compared with linoleic acid, linolelaidic acid increased LDL-cholesterol (C) and HDL-C by 154% (P < 0.001) and 50% (P = 0.016), respectively, whereas palmitic acid increased LDL-C by 17% (P > 0.1) and did not affect HDL-C. The LDL-C to HDL-C ratios were 0.70, 1.18 and 0.96 with linoleic, linolelaidic and palmitic acids, respectively. These differences were not due to altered LDL receptor activity. The PL to C ratios of HDL particles were 1.61, 0.40 and 0.77 with linoleic acid, linolelaidic acid and palmitic acid, respectively. These results suggest that relative to cis polyunsaturated and saturated fatty acids, trans PUFA more adversely affect the concentration and composition of apoA-I- and apoB-containing lipoproteins secreted by HepG2 cells.

Apolipoprotein A-I↗