bluuebunny/crossref_metadata_2025 huggingface dataset:
Formation of cleavage products by autoxidation of lycopene
Authors: Kim Seon‐Jae , Nara Eiichi , Kobayashi Hidetaka , Terao Junji , Nagao Akihiko
Published: November 2006

The cleavage products formed by autoxidation of lycopene were evaluated in order to elucidate possible oxidation products of lycopene in biological tissues. Lycopene solubilized at 50 μM in toluene, aqueous Tween 40, or liposomal suspension was oxidized by incubating at 37°C for 72 h. Among a number of oxidation products formed, eight products in the carbonyl compound fraction were identified as 3,7,11‐trimethyl‐2,4,6,10‐dodecatetraen‐1‐al, 6,10,14‐trimethyl‐3,5,7,9,13‐pentadecapentaen‐2‐one, acycloretinal, apo‐14′‐lycopenal, apo‐12′‐lycopenal, apo‐10′‐lycopenal, apo‐8′‐lycopenal, and apo‐6′‐lycopenal. These correspond to a series of products formed by cleavage in the respective 11 conjugated double bonds of lycopene. The maximal formation of acycloretinal was 135 nM in toluene, 49 nM in aqueous Tween 40, and 64 nM in liposomal suspension. Acycloretinoic acid was also formed by autoxidation of lycopene, although its formation was lower in the aqueous media than in toluene. The pig liver homogenate had the ability to convert acycloretinal to acycloretinoic acid, comparable to the conversion of all‐trans‐retinal to all‐trans‐retinoic acid. These results suggest that lycopene might be cleaved to a series of apolycopenals and short‐chain carbonyl compounds under the oxidative conditions in biological tissues and that acycloretinal is further enzymatically converted to acycloretinoic acid.
The effect of conjugated linoleic acid on platelet function, platelet fatty acid composition, and blood coagulation in humans
Authors: Benito P. , Nelson G. J. , Kelley D. S. , Bartolini G. , Schmidt P. C. , Simon V.
Published: November 2006

Despite extensive research on conjugated linoleic acid (CLA) showing multiple beneficial effects in animal models, little is known about the role of dietary CLA in human health. To investigate if the beneficial effects of CLA seen in animal models are relevant to humans, we conducted a study with 17 healthy female volunteers who lived in the Metabolic Research Unit of the Western Human Nutrition Research Center for 93 d. This paper reports only the results from this study that are related to the effects of CLA supplementation on blood coagulation, platelet function, and platelet fatty acid composition. Throughout the study, the subjects were fed a low‐fat diet (30 en% fat, 19 en% protein, and 51 en% carbohydrate) consisting of natural foods with the recommended dietary allowances for all known nutrients. After a 30‐d stabilization period, subjects were randomly assigned to either an intervention group (n=10) whose diet was supplemented with 3.9 g/d of CLA or a control group (n=7) who received an equivalent amount of sunflower oil consisting of 72.6% linoleic acid with no detectable CLA. Platelet aggregation was measured in platelet‐rich plasma using adenosine diphosphate, collagen, and arachidonic acid agonists. No statistical difference was detected between the amount of agonist required to produce 50% aggregation of platelet‐rich plasma before and after the subjects consumed the CLA, with the exception of a decrease in response to collagen. This decrease was found in both control and intervention groups with no significant difference between the groups, suggesting that both linoleic acid (sunflower oil) and CLA might have similar effects on platelet function. The prothrombin time, activated partial thromboplastin time, and the antithrombin III levels in the subjects were determined. Again, there was no statistically significant difference in these three parameters when pre‐and post‐CLA consumption values were compared. The in vivo bleeding times were also unaffected by CLA supplementation (10.4+2.8 min pre‐ and 10.2+1.6 min postconsumption). Platelet fatty acid composition was not markedly influenced by the consumption of dietary CLA, although there was a small increase in the amount of the 9 cis, 11 trans‐18∶2 isomer normally present in platelets after feeding CLA for 63 days. In addition, small amounts of the 8 trans, 10 cis‐18∶2 and the 10 trans, 12 cis‐18∶2 isomers were detected in the platelets along with traces of some of the other isomers. Thus, when compared to sunflower
The effect of conjugated linoleic acid on plasma lipoproteins and tissue fatty acid composition in humans
Authors: Benito P. , Nelson G. J. , Kelley D. S. , Bartolini G. , Schmidt P. C. , Simon V.
Published: November 2006

Conjugated linoleic acid (CLA) has been suggested by some animal studies to possess antiatherogenic properties. To determine, in humans, the effect of dietary CLA on blood lipids, lipoproteins, and tissue fatty acid composition, we conducted a 93‐d study with 17 healthy female volunteers at the Metabolic Research Unit of the Western Human Nutrition Research Center. Throughout the study, subjects were fed a low‐fat diet [30 energy percent (en%) fat, 19 en% protein, and 51 en% carbohydrate] that consisted of natural foods with the recommended dietary allowances for all known nutrients. After a 30‐d stabilization period, subjects were randomly assigned to either an intervention group (n=10) supplemented daily with capsules containing 3.9 g of CLA or a control group (n=7) that received an equivalent amount of sunflower oil. The CIA capsules (CLA 65%) contained four major cis/trans geometric isomers (11.4% 9 cis‐,11 trans‐18∶2; 10.8% 8 trans‐,10 cis‐18∶2; 15.3% 11 cis‐,13 trans‐18∶2; and 14.7% 10 trans‐, 12 cis‐18∶2) and their corresponding cis/cis (6.74% total) and trans/trans (5.99% total) varieties in smaller amounts. Fasting blood was drawn on study days 30 (end of the stabilization period), 60 (midpoint of the intervention period), and 93 (end of the intervention period). Adipose tissue samples were taken on days 30 and 93. CLA supplementation for 63 d did not change the levels of plasma cholesterol, low density lipoprotein cholesterol, high density lipoprotein cholesterol, and triglycerides. The weight percentage of CLA in plasma increased from 0.28±0.06 to 1.09±0.31 (n=10, P<0.05) after the supplementation. The 9 cis‐,11 trans‐isomer was the most prominent variety followed by the 11 cis‐,13 trans‐ and 10 trans‐,12 cis‐isomers in lesser amounts. CLA in adipose tissue was not influenced by the supplementation (0.79±0.18 to 0.83±0.19 wt%) (n=10) and the 9 cis‐,11 trans‐variety was the only isomer present. Thus, contrary to findings from some animal studies, CLA does not seem to offer health benefits, in the short term, regarding the prevention of atherosclerosis in humans. CLA supplementation for 2 mon did not alter the blood cholesterol or lipoprotein levels of healthy, normolipidemic subjects. The supplementation did increase CLA in the plasma but only 4.23% of the ingested CLA was present in the plasma at any given time. No adverse effect of CLA supplementation was detected in this study.
Unique phospholipid metabolism in mouse heart in response to dietary docosahexaenoic or α‐linolenic acids
Authors: Watkins S. M. , Lin T. Y. , Davis R. M. , Ching J. R. , DePeters E. J. , Halpern G. M. , Walzem R. L. , German J. B.
Published: November 2006

Diet and fatty acid metabolism interact in yet unknown ways to modulate membrane fatty acid composition and certain cellular functions. For example, dietary precursors or metabolic products of n‐3 fatty acid metabolism differ in their ability to modify specific membrane components. In the present study, the effect of dietary 22∶6n−3 or its metabolic precursor, 18∶3n−3, on the selective accumulation of 22∶6n−3 by heart was investigated. The mass and fatty acid compositions of individual phospholipids (PL) in heart and liver were quantified in mice fed either 22∶6n−3 (from crocodile oil) or 18∶3n−3 (from soybean oil) for 13 wk. This study was conducted to determine if the selective accumulation of 22∶6n−3 in heart was due to the incorporation of 22∶6n−3 into cardiolipin (CL), a PL most prevalent in heart and known to accumulate 22∶6n−3. Although heart was significantly enriched with 22∶6n−3 relative to liver, the accumulation of 22∶6n−3 by CL in heart could not quantitatively account for this difference. CL from heart did accumulate 22∶6n−3, but only in mice fed preformed 22∶6n−3. Diets rich in non‐22∶6n−3 fatty acids result in a fatty acid composition of phosphatidylcholine (PC) in heart that is unusually enriched with 22∶6n−3. In this study, the mass of PC in heart was positively correlated with the enrichment of 22∶6n−3 into PC. The increased mass of PC was coincident with a decrease in the mass of phosphatidylethanolamine, suggesting that 22∶6n−3 induced PC synthesis by increasing phosphatidylethanolamine‐N‐methyltransferase activity in the heart.
1‐14C‐Linoleic acid distribution in various tissue lipids of guinea pigs following an oral dose
Authors: Fu Zhong , Attar‐Bashi Nadia M. , Sinclair Andrew J.
Published: November 2006

A recent study on the metabolism of 1‐14C‐α‐linolenic acid in the guinea pig revealed that the fur had the highest specific activity of all tissues examined, 48 h after dosing. The present study investigated the pattern of tissue lipid labeling following an oral dose of 1‐14C‐linoleic acid after the animals had been dosed for the same time as above. Guinea pigs were fed one of two diets with a constant linoleic acid content (18% total fatty acids) and a different content of α‐linolenic acid (0.3 or 17.3%) from weaning for 3 wk and 1‐14C‐linoleic acid was given orally to each animal for 48 h prior to sacrifice. The most highly labeled tissues (dpm/mg of linoleic acid) were liver, followed by brain, lung and spleen, heart, kidney and adrenal and intestines, in both diet groups. The liver had almost a three‐fold higher specific activity than skin and fur which was more extensively labeled than the adipose and carcass. Approximately two‐thirds of the label in skin plus fur was found in the fur which, because of a low lipid mass, would indicate that the fur was highly labeled. All tissues derived from animals on the diet with the low α‐linolenic acid level were significantly more labeled than the tissues from the animals on the high α‐linolenic acid diet, by a factor of 1.5 to 3. The phospholipid fraction was the most highly labeled fraction in the liver, free fatty acids were the most labeled fraction in skin & fur, while triacyglycerols were the most labeled in the carcass and adipose tissue. In these tissues, more than 90% of the radioactivity was found in fatty acids with 2‐double bonds in the tissue lipids. These data indicate that the majority of label found in guinea pig tissues 48 h after dosing was still associated with a fatty acid fraction with 2‐double bonds, which suggests there was little metabolism of linoleic acid to more highly unsaturated fatty acids in this time frame. In this study, the labeling of guinea pig tissues with linoleic acid, 48 h after dosing, was quite different from the labeling with α‐linolenic acid reported previously. The retention of the administered radioactivity from 14C‐linoleic acid in the whole body lipids was 1.6 times higher in the group fed the low α‐linolenic acid diet (diet contained a total of 1.8 g PUFA/100 g diet)compared with the group fed the high α‐linolenic acid diet (diet contained 3.6 g PUFA/100 g diet). The lack of retention of 14C‐labeled lipids in the whole body would be consistent with an increased rate of β‐oxidation of the labeled fatty acid on the diet rich in PUFA, a result supported by other studies using direct measurement of labeled carbon dioxide.
Effects of diets enriched in n−6 or n−3 fatty acids on cholesterol metabolism in older rats chronically fed a cholesterol‐enriched diet
Authors: Fukushima Michihiro , Ohhashi Tetsu , Ohno Syugo , Saitoh Hidetoshi , Sonoyama Kei , Shimada Ken‐ichiro , Sekikawa Mitsuo , Nakano Masuo
Published: November 2006

Hypocholesterolemic effects in older animals after long‐term feeding are unknown. Therefore, aged rats (24 wk of age) fed a conventional diet were shifted to diets containing 10% perilla oil [PEO; oleic acid+linoleic acid+α‐linolenic acid; n−6/n−3, 0.3; polyunsaturated fatty acid/saturated fatty acid (P/S), 9.6], borage oil [oleic acid+linoleic acid+α‐linolenic acid; n−6/n−3, 15.1; P/S, 5.3], evening primrose oil (FPO; linoleic acid+γ‐linolenic acid; P/S, 10.5), mixed oil (MIO; oleic acid+linoleic acid+γ‐linolenic acid+α‐linolenic acid; n−6/n−3, 1.7; P/S, 6.7), or palm oil (PLO; palmitic acid+oleic acid+linoleic acid; n−6/n−3, 25.3; P/S, 0.2) with 0.5% cholesterol for 15 wk in this experiment. There were no significant differences in the food intake and body weight gain among the groups. The liver weight in the PEO (n−6/n−3, 0.3) group was significantly higher than those of other groups in aged rats. The serum total cholesterol and very low density lipoprotein (VLDL) +intermediate density lipoprotein (IDL)+low density lipoprotein (LDL)‐cholesterol concentrations of the PLO (25.3) group were consistently higher than those in the other groups. The serum high density lipoprotein cholesterol concentrations of the PEO (0.3) and EPO groups were significantly lower than in the other groups at the end of the 15‐wk feeding period. The liver cholesterol concentration of the PLO (25.3) group was significantly higher than those of other groups. There were no significant differences in the hepatic LDL receptor mRNA level among the groups. Hepatic apolipoprotein (apo) B mRNA levels were not affected by the experimental conditions. The fecal neutral steroid excretion of the PLO (25.3) group tended to be low compared to the other groups. The results of this study demonstrate that both n\t‐6 fatty acid and n\t‐3 fatty acids such as \gg‐linolenic acid and \ga‐linolenic acid inhibit the increase of serum total cholesterol and VLDL+IDL+LDL‐cholesterol concentrations of aged rats in the presence of excess cholesterol in the diet compared with dietary saturated fatty acid.
Acute effect of ethanol on 7‐hydroperoxycholesterol in muscle and liver
Authors: Adachi Junko , Asano Migiwa , Ueno Yasuhiro , Marway Jaspaul S. , Camilleri Peter M. , Peters Timothy J. , Preedy Victor R.
Published: November 2006

We tested the hypotheses that ethanol sensitivities of muscle and liver can be discerned in the initial periods of ethanol exposure, especially when acetaldehyde levels are markedly raised with cyanamide, an aldehyde dehydrogenase inhibitor. To test this, we measured cholesterol hydroperoxides in soleus (Type I) and plantaris (Type II) muscle in four groups of rats acutely (i.e., 2.5 h) exposed to: [S] saline (control), [Cy] cyanamide, [EtOH] ethanol, or [Cy+EtOH] cyanamide+ ethanol. Comparative reference was also made to the response of the liver. After 2.5 h, ethanol alone significantly increased 7α‐hydroperoxycholest‐5‐en‐3β‐ol (7α‐OOH) and 7β‐hydroperoxycholest‐5‐en‐3β‐ol (7β‐OOH) levels in plantaris muscle. Identical qualitative effects were seen in rats treated with cyanamide+ethanol, but there was no discernible difference between groups [LtOH] and [Cy+EtOH]. In both the soleus muscle and liver, none of the treatments with either ethanol or cyanamide+ethanol had any effect on any of the measured parameters. This is the first report of a differential response of 7α‐OOH and 7β‐OOH in Type II, compared to Type I predominant muscles, and the first time that muscle has been shown to be more sensitive than the liver in terms of its lipid marker response to oxidative stress. Perturbations in the muscle membrane lipid domain may contribute to impaiment of muscle in alcoholism.
Purification and characterization of an extracellular lipase from Penicillium candidum
Authors: Ruiz Beatriz , Farrés Amelia , Langley Elizabeth , Masso Felipe , Sánchez Sergio
Published: November 2006

Penicillium candidum produces and secretes a single extracellular lipase with a monomer molecular weight of 29 kDa. However, this enzyme forms dimers and higher molecular weight aggregates under nondenaturing conditions. The lipase from P. candidum was purified 37‐fold using Octyl‐Sepharose CL‐4B and DEAE‐Sephadex columns. The optimal assay conditions for lipase activity were 35°C and pH 9. The lipase was stable in the pH range of 5–6 with a pl of 5.5, but rapid loss of the enzyme activity was observed above 25°C. Tributyrin was found to be the best substrate for the P. candidum lipase, among those tested. Metal ions such as Fe2+ and Cu2+ inhibited enzymatic activity and only Ca2+ was able to slightly enhance lipase activity. Ionic detergents inhibited the activity of the enzyme, whereas nonionic detergents stimulated lipase activity.
Comparative investigation of human stratum corneum ceramides
Authors: Vietzke Jens‐Peter , Brandt Oliver , Abeck Dietrich , Rapp Claudius , Strassner Manfred , Schreiner Volker , Hintze Ulrich
Published: November 2006

The stratum corneum (SC) requires ceramides, cholesterol, and fatty acids to provide the cutaneous permeability barrier. SC lipids can be analyzed by normal‐phase high‐performance thin‐layer chromatography (HPTLC). However, without further analysis, some uncertainty remains about the molecular composition of lipids represented by every TLC band of an unknown sample. We therefore analyzed each ceramide band further by subjecting the isolated lipids to a direct coupling of reversed‐phase high‐performance liquid chromatography and electrospray ionization‐mass spectrometry (HPLC/ESI‐MS, or IC/MS). IC/MS analysis and ESI‐MS/MS negative ion and collision‐induced dissociation experiments revealed that ceramide band 4 contained not only N‐(ω‐OH‐acyl)acyl‐6‐OH‐sphingosine, Cer(EOH), but also N‐(α‐OH‐acyl)‐sphingosine. Band 5 exclusively contained N‐acyl‐6‐OH‐sphingosine. Our results demonstrate the benefit of LC/MS analysis for selective identification of human SC ceramides. Moreover, the combination of HPTLC for pre‐separation and LC/MS for identification of lipids is an even more powerful tool for detailed ceramide analysis.
Changes in conjugated linolenic acid composition within samples obtained from a single source
Authors: Adlof R. O. , Copes L. C. , Walter E. L.
Published: November 2006

Conjugated linoleic acid (CLA; 9c, 11t‐18∶2) and CLA isomers have been reported, in animals, to exhibit a variety of health‐related benefits. Silver ion high‐performance liquid chromatography (Ag‐HPLC) was found to provide better resolution of the isomes than gas chromatography. Most commercially available samples of CLA, prepared by base‐catalyzed isomerization of linoleic acid (9c, 12c‐18∶2), are conposed of mixtures of four major isomers. While these isomers have been characterized, we found significant changes in CLA isomer ratios within samples obtained from the same producer/commercial supplier over a period of 1.5 yr. In the first sample, the four cis/trans isomers (8t, 10c‐18∶2, 9c, 11t‐18∶2, 10t, 12c‐18∶2 and 11c, 13t‐18∶2) were present in a ratio of approximately 1∶2∶2∶1, while in the second sample they were present in almost equal proportions. If indeed certain daily levels of CLA intake are required to produce suggested health benefits in humans, changes in concentrations of specific CLA isomers could significantly impact these effects. Care must be taken to analyze the CLA used in human and animal studies.
A new Δ7‐polyunsaturated fatty acid in taxus spp. Seed lipids, dihomotaxoleic (7,11–20∶2) acid
Authors: Destaillats Frédéric , Wolff Robert L. , Angers Paul
Published: November 2006

A previously undescribed fatty acid, all‐cis 7, 11–20∶2 (dihomotaxoleic acid, DHT), has been characterized by gas chromatography‐mass spectrometry as being present (approximately 0.1%) in seed oils of two Taxaceae containing high levels (11–16%) of taxoleic acid (all‐cis 5,9–18∶2). This compound was absent from oils of 10 other conifer genera, as well as from one member of Taxaceae containing very low amounts of taxoleic acid, suggesting that DHT is a taxoleic acid elongation product.
Oxidative catabolism of α‐tocopherol in rat liver microsomes
Authors: Van Houte Hilde , de Hoffmann Edmond , Van Veldhoven Paul P. , Mannaerts Guy P. , Carchon Hubert , Baes Myriam I. , Declercq Peter E.
Published: November 2006

The goal of this study was to clarify the mechanism responsible for the catabolism of α‐tocopherol. The vitamin, bound to albumin, was incubated with rat liver microsomes and appeared to be broken down. Optimal production of the metabolite was obtained when 1 mg of microsomal protein was incubated with 36 μM of α‐tocopherol in the presence of 1.5 mM of NADPH. Chromatographic and mass spectrometric analyses of the metabolite led to the conclusion that it consists of an ω‐acid with an opened chroman ring, although we could not perform nuclear magnetic resonance analysis to confirm this. Our data show that α‐tocopherol is ω‐oxidized to a carboxylic acid and that this process can occur in rat liver microsomes in the presence of NADPH and O2. The oxidation to the quinone structure appears to be a subsequent event that may be artifactual and/or catalyzed by a microsomal enzyme(s).
Modulation of prostaglandin H synthase activity by conjugated linoleic acid (CLA) and specific CLA isomers
Authors: Bulgarella Jennifer A. , Patton David , Bull Arthur W.
Published: November 2006

Conjugated linoleic acid (CLA) has been shown to inhibit tumorigenesis in animal models and is cytostatic to numerous cell lines in vitro. However, the mechanism of action is unknown. In the current study, we determined the effects of CLA and specific isomers of CLA on the rate of oxygenation of arachidonic acid by prostaglandin H synthase (PGHS) in ram seminal vesicle microsomes. The enzyme was incubated with 0.1 to 100 μM CLA or specific isomers of CLA for 2 min prior to the addition of 44 to 176 μM arachidonate. The isomers tested were 9(E),11(E) CLA; 9(Z),11(E) CLA; 9(Z),11(Z) CLA, and 10(E),12(Z) CLA. For a positive inhibitor control, flurbiprofen was used at 0.75 to 2.50 μM. Enzyme activity was assessed by measuring the rate of oxygen consumption. Inclusion of CLA or specific isomers of CLA in the incubation mixtures inhibits PGHS. The efficacy differs for each isomer, with the 9(Z),11(E) CLA isomer being the most effective and the 9(Z),11(Z) CLA isomer being the least effective inhibitor among the four CLA isomers tested. The Ki values obtained by Dixon replots range from 18.7 μM for the most effective isomer, 9(Z),11(Z) CLA, to 105.3 μM for the least effective isomer, 9(Z),11(Z) CLA. The Ki value for flurbiprofen with ram seminal vesicle microsomes was 0.33 μM. As the concentration of arachidonate was increased, the CLA‐dependent inhibition of PGHS decreased, suggesting competitive inhibition. The results of this study demonstrate the potential of CLA and specific isomers of CLA to modulate prostaglandin biosynthesis.
Hen egg yolk and white contain high amounts of lysophosphatidic acids, growth factor‐like lipids: Distinct Molecular species compositions
Authors: Nakane Shinji , Tokumura Akira , Waku Keizo , Sugiura Takayuki
Published: November 2006

Hen egg yolk and white were found to contain high amounts of lysophosphatidic acid (acyl LPA) in addition to small amounts of lysoplasmanic acid (alkyl LPA). The levels of acyl LPA in hen egg yolk (44.23 nmol/g tissue) and while (8.81 nmol/g tissue) were on the same order as or higher than the levels of acyl LPA known to be required to elicit biological responses in various animal tissues. Noticeably, there is a marked difference between the fatty acid composition of egg yolk acyl LPA and of egg white acyl LPA; egg yolk acyl LPA predominantly contains saturated fatty acids as the acyl moiety, whereas egg white acyl LPA primarily contains polyunsaturated fatty acids. We found that the level of acyl LPA, especially polyun‐saturated fatty acid‐containing acyl LPA, in egg white was augmented markedly during the incubation at 37°C, while there was no change in egg yolk. We confirmed that egg white contains both the substrate, i.e., polyunsaturated fatty acid‐containing lysophosphatidylcholine (LPC), and the enzyme activity catalyzing the hydrolysis of polyunsaturated fatty acid‐containing LPC to the corresponding acyl LPA. Egg yolk LPA and egg white LPA may play separate physiological roles in the development, differentiation, and growth of embryos.
Studies on effects of dietary fatty acids as related to their position on triglycerides
Authors: Hunter J. Edward
Published: November 2006

This article reviews published literature on how the stereospecific structure of dietary triglycerides may affect lipid metabolism in humans. Animal studies have shown enhanced absorption of fatty acids in the sn‐2 position of dietary triglycerides. Increasing the level of the saturated fatty acid palmitic acid in the sn‐2 position (e.g., by interesterification of the fat to randomize the positions of the fatty acids along the glycerol backbone) has been shown in rabbits to increase the atherogenic potential of the fat without impacting levels of blood lipids and lipoproteins. In contrast, enhancing the level of stearic acid in the sn‐2 position has not been found to affect either atherogenic potential or levels of blood lipids and lipoproteins in rabbit. Fatty acids other than palmitic and stearic have not been studied systematically with respect to possible positional effects. A limited number of human studies have shown no significant effects of interesterified fats on blood lipid parameters. However, it is unknown whether modifying the stereospecific structure of dietary triglycerides would affect atherogenicity or other long‐term health conditions in humans. It is possible that incorporation of palmitic acid into the sn‐2 position of milk fat is beneficial to the human infant (as a source of energy for growth and development) but not to human adults. Additional research is needed to determine whether processes like interesterification, which can be used to alter physical parameters of dietary fats (e.g., melting characteristics), may result in favorable or unfavorable long‐term effects in humans.
Fatty acid content of plasma lipids and erythrocyte phospholipids are altered following burn injury
Authors: Pratt Vera C. , Tredget Edward E. , Clandinin M. Thomas , Field Catherine J.
Published: November 2006

The objective of this study was to examine compositional and quantitative changes in fatty acids of plasma components and red blood cell phospholipids (PL) immediately following and during recovery from burn injury. Subjects (n=10) with >10% total body surface area burn had blood drawn at specific timepoints (0 to >50 d) following burn injury. Fatty acid composition of red blood cell PL and plasma PL, cholesteryl esters (CE), and triglycerides was determined using gas‐liquid chromatography after separating each fraction from extracted lipids by thin‐layer chromatography. Total plasma PL and CE in burn patients were lower than in healthy control subjects with reduced 20∶4n−6, n−6, and n−3 fatty acids and higher levels of monounsaturated and saturated fatty acids early after burn. CE levels remained half that of healthy control values up to 50 d post‐burn. Red blood cell PL had decreased 20∶4n−6 content and profiles similar to that of an essential fatty acid deficiency early after burn. These results suggest an impairment in lipoprotein and polyunsaturated fatty acid metabolism in the early post‐burn period. Lower levels of 20∶4n−6 and n−3 fatty acids in every plasma fraction suggest increased use of these fatty acids for wound healing and immune function following burn injury. Further work is needed to determine the ability of burn patients to utilize essential fatty acids in order to design nutritional intervention that promotes wound healing and immunological functions consistent with recovery in these patients.
Regulation of intestinal apolipoprotein A‐I synthesis by dietary phosphatidylcholine in newborn swine
Authors: Wang Heng , Du Jianhui , Lu Song , Yao Ying , Hunter Felicia , Black Dennis D.
Published: November 2006

Phospholipid (PL) from both dietary sources and biliary secretions may be important in the regulation of intestinal apolipoprotein (apo) synthesis. We previously demonstrated the up‐regulation of apo A‐I secretion by phosphatidylcholine (PC) in a newborn piglet intestinal epithelial cell line. We hypothesized that dietary PC increases small intestinal apo A‐I synthesis in vivo in the newborn piglet. Two‐day‐old female swine were fed by gavage for 48 h. Diets consisted of a formula containing 51% of calories as triacylglycerol providing 180 kcal/kg/24 h. The experimental group (+PC, n=7) received 1 g/L added soybean PC, and the control group (−PC, n=7) received no added PC. At the end of the study period, jejunal apo A‐I, B, and A‐IV synthesis was measured, and apo A‐I mRNA levels were quantitated. Jejunal mucosal PI content and serum lipids and apo B and A‐I levels were measured. Jejunal apo A‐I synthesis was almost twice as high in the +PC group as compared to the −PC group with no difference in apo A‐I mRNA levels. Jejunal content of PL was higher in the +PC group than in the −PC group. There were no differences in jejunal apo B and A‐IV synthesis or serum levels of lipids and apo‐lipoproteins between the two groups. Dietary PC supplementation in newborn swine up‐regulated jejunal apo A‐I synthesis. Apo A‐IV synthesis, which is sensitive to fatty acid flux, was not significantly increased, which suggests a specific effect of PC on apo A‐I synthesis. Lumenal PC may be important in the regulation of intestinal apo A‐I synthesis in the neonate.
Studies of phospholipid metabolism, proliferation, and secretion of stably transfected insulinoma cells that overexpress group VIA phospholipase A2
Authors: Ma Zhongmin , Bohrer Alan , Wohltmann Mary , Ramanadham Sasanka , Hsu Fong‐Fu , Turk John
Published: November 2006

A cytosolic 84 kDa Group VIA phospholipase A2 (iPLA2β) that does not require Ca2+ for catalysis was cloned from Chinese hamster ovary (CHO) cells, murine P388D1 cells, pancreatic islet β‐cells, and other sources. Proposed iPLA2β functions include participation in phosphatidylcholine (PC) homeostasis by degrading excess PC generated in CHO cells that overexpress CTP:phosphocholine cytidylyltransferase (CT), which catalyzes the rate‐limiting step in PC biosynthesis; participation in biosynthesis of arachidonate‐containing PC species in P388D1 cells by generating lysophosphatidylcholine (IPC) acceptors for arachidonate incorporation; and participation in signaling events in insulin secretion from islet β‐cells. To further examine iPLA2β functions in β‐cells, we prepared stably transfected INS‐1 insulinoma cell lines that overexpress iPLA2β activity eightfold compared to parental INS‐1 cells or to INS‐1 cells transfected with an empty retroviral vector that did not contain iPIA2β cDNA. The iPLA2β‐overexpressing cells exhibit a twofold increase in CT activity compared to parental cells but little change in rates of [3H] choline incorporation into or disappearance from PC. Electrospray ionization (ESI) tandem mass spectrometric measurements indicate that iPLA2β‐overexpressing cells have 1.5‐fold higher LPC levels than parental INS‐1 cells but do not exhibit increased rates of [3H]arachidonate incorporation into phospholipids, and incorporation is unaffected by a bromoenol lactone (BEL) suicide substrate inhibitor of iPLA2β. The rate of appearance of arachidonate‐containing phosphatidylethanolamine species visualized by ESI mass spectrometry is also similar in iPLA2β‐overexpressing and parental INS‐1 cells incubated with supplemental arachidonic acid, and this process is unaffected by BEL. Compared to parental INS‐1 cells, iPLA2β‐overexpressing cells proliferate more rapidly and exhibit amplified insulin secretory responses to a protein kinase C‐activating phorbol ester, glucose, and a cAMP analog. These findings suggest that iPLA2β plays a signaling role in β‐cells that differs from housekeeping functions in PC biosynthesis and degradation in P388D1 and CHO cells.
Metabolism of an oxysterol, 7‐ketocholesterol, by sterol 27‐hydroxylase in hepG2 cells
Authors: Lyons Malcolm A. , Brown Andrew J.
Published: November 2006

7‐Ketocholesterol (7K) is a quantitatively important oxysterol in both atherosclerotic lesions and macrophage foam cells. We reported recently that radiolabeled 7K delivered to rodents in a modified lipoprotein or chylomicron remnantlike emulsion, both cleared predominantly by the liver, was rapidly excreted into the intestine as water‐soluble products, presumably bile acids. Herein, we aimed to elucidate the early or initial reactions in 7K metabolism. The hypothesis was tested that sterol 27‐hydroxylase, a mitochondrial cytochrome P450 and the first enzyme of the acidic bile acid pathway, is responsible for the initial metabolism of 7K by HepG2 cells, a human hepatoblastoma cell‐line. The 27‐hydroxylated product of 7K (27OH‐7K) was shown to be the initial, lipid‐soluble product of 7K metabolism. It was produced in mitochondrial incubations and whole cells and was readily released into the media from cells. Intact cells generated metabolites of 7K that had undergone conversion from lipid‐soluble precusors to water‐soluble products rapidly and extensively. Their production was ablated with cyclosporin A, a sterol 27‐hydroxylase inhibitor. Furthermore, we demonstrated the effectiveness of two novel selective inhibitors of this enzyme, GW273297X and GI268267X. These inhibitors also ablated the production of water‐soluble products by cells; and the inhibitor of choice, GW273297X, decreased the production of 27OH‐7K in mitochondrial preparations. This is the first study to demonstrate that sterol 27‐hydroxylase plays an important role in the metabolism of oxysterols such as 7K in liver cells.
Modeling of α‐tocopherol loss and oxidation products formed during thermoxidation in triolein and tripalmitin mixtures
Authors: Verleyen T. , Kamal‐Eldin A. , Dobarganes C. , Verhe R. , Dewettinck K. , Huyghebaert A.
Published: November 2006

The degradation of α‐tocopherol and the formation of α‐tocopherol and triacylglycerol oxidation products at high temperatures (150–250°C) over a heating period (0–4h) for a model system ranging between triolein and tripalmitin were modeled by use of an experimental design. The oxidation products of α‐tocopherol formed under these conditions were α‐tocopherolquinone (1.4–7.7%) and epoxy‐α‐tocopherolquinones (4.3–34.8%). The results indicate a very high susceptibility of α‐tocopherol to capture peroxyl radicals upon oxidation, leading to the formation of polar tocopherol oxidation products. Both α‐tocopherolquinone and epoxy‐α‐tocopherolquinones were not stable upon prolonged heating and were further degraded to other unknown oxidation products. The kinetics of α‐tocopherol oxidation were significantly influenced by the triolein/tripalmitin ratio. By increasing the level of triacylglycerol unsaturation the rate of α‐tocopherol recovery after heating increased significantly from 2.2 to 44.2% whereas in the meantime triacylglycerol polymerization increased from 0 to 3.7%.
Positional distribution of highly unsaturated fatty acids in triacyl‐sn‐glycerols of Artemia nauplii enriched with docosahexaenoic acid ethyl ester
Authors: Ando Yasuhiro , Oomi Yoshiaki
Published: November 2006

This paper presents the positional distribution of fatty acids in triacyl‐sn‐glycerols (TAG) of Artemia nauplii used in aquaculture as a live food for marine fish larvae. The nauplii were enriched with docosahexaenoic acid (DHA) ethyl ester (EE) in the form of gelatin‐acacia microcapsules for 4, 18, and 24 h. TAG of the initial, enriched, and unenriched Artemia nauplii were subjected to stereospecific analysis. A remarkable increase of DHA content in the enriched Artemia TAG confirmed the view that DHA‐EE is effectively assimilated and incorporated into the TAG fraction of Artemia nauplii. TAG of the nauplii enriched with 25 mg/L of DHA‐EE contained DHA at concentrations of 5.9–6.8, 4.3–6.0, and 14.3–22.3 mol% in the sn‐1, sn‐2, and sn‐3 positions, respectively. When the nauplii were enriched with 100 mg/L of DHA‐EE, proportions of DHA in the sn‐1, sn‐2, and sn‐3 positions were 5.2–8.6, 3.9–6.0, and 12.2–25.4 mol%, respectively. In all of the enriched Artemia, DHA was preferentially located in the sn‐3 position followed in sequence by the sn‐1 and sn‐2 positions. The lower content of DHA in the sn‐1 and sn‐2 positions was consistent with low content of this acid in 1,2‐diacyl‐sn‐glycerophospholipids. When fish larvae are reared on Artemia nauplii enriched with LL‐type DHA oil, the larvae feed on DHA esterified in TAG with a positional distribution pattern similar to that of marine mammals (sn‐3≫sn‐1>sn‐2) rather than that of fish or marine invertebrates (sn‐2≫sn‐3>sn‐1).
Determination of stereochemical configuration of the glycerol moieties in glycoglycerolipids by chiral phase high‐performance liquid chromatography
Authors: Takahashi Yoshinori , Itabashi Yutaka , Suzuki Minoru , Kuksis Arnis
Published: November 2006

This study reports a simple and sensitive method for determining the absolute configuration of the glycerol moieties in glycoglycerolipids. The method is based on chiral phase high‐performance liquid chromatography (HPLC) separations of enantiomeric di‐ and monoacylglycerols released from glycosyldi‐ and monoacylglycerols, respectively, by periodate oxidation followed by hydrazinolysis. The released di‐ and monoacylglycerols were chromatographed as their 3,5‐dinitrophenylurethane (3,5‐DNPU), and bis(3,5‐DNPU) derivatives, respectively. The derivatives were separated on two chiral phases of opposite configuration, (R)‐and (S)‐1‐(1‐naphthyl)ethylamine polymers for diacylglycerols and N‐(R)‐1‐(1‐naphthyl)ethylaminocarbonyl‐(S)‐valine and N‐(S)‐1‐(1‐naphyl)ethylamino‐carbonyl‐(R)‐valine for monoacylglycerols. Clear enantiomer separations, which permit the assignment of the glycerol configuration, were achieved for sn‐1,2(2,3)‐dicyl‐ and sn‐1(3)‐monoacylglycerols generated from linseed oil triacylglycerols by partial Grignard degradation on all the chiral stationary phases employed. Using the method, we have determined the glycerol configuration in the glycosyl‐diacylglycerols (monogalactosyl‐, digalactosyl‐, and sulfquinovo‐syldiacylglycerols) and glycosylmonoacylglycerols (monogalactosyl‐, digalactosyl‐, and sulfoquinovosylmonoacylglycerols) isolated from spinach leaves and the coralline red alga Corallina pilulifera. The results clearly showed that the glycerol moieties in all the glycoglycerolipids examined have S‐configuration sn‐1,2‐diacyl‐ and sn‐1‐monoacylglycerols). The new method demonstrates that chiral phase HPLC provides unambiguous information on the configuration of the glycerol backbone in natural glycosyldi‐ and monoacylglycerols, and that the two‐step liberation of the free acylglycerols does not compromise glycerol chirality.
Genomic and functional characterization of polyunsaturated fatty acid biosynthesis in Caenorhabditis elegans
Authors: Napier Johnathan A. , Michaelson Louise V.
Published: November 2006

The biosynthetic pathway for polyunsaturated fatty acids in the model animal Caenorhabditis elegans was examined in the context of the completed genome sequence. The genomic organization and location of seven desaturase genes and one elongase activity, all previously identified by functional characterization, were elucidated. A pathway for the biosynthesis of polyunsaturated fatty acids in C. elegans was proposed based on these genes. The role of gene duplication in enzyme evolution and proliferation is discussed.
Conjugated linoleic acid supplementation in humans: Effects on fatty acid and glycerol kinetics
Authors: Zambell Kirsten L. , Horn William F. , Keim Nancy L.
Published: November 2006

Recent studies with mouse adipocytes have shown that dietary conjugated linoleic acid (CLA) may reduce body fat by increasing lipolysis. The present study examined the effect of CLA supplementation on fatty acid and glycerol kinetics in six healthy, adult women who were participating in a controlled metabolic ward study. These women were fed six CLA capsules per day (3.9 g/d) for 64 d following a baseline period of 30 d. The subjects were confined to a metabolic suite for the entire 94‐d study, where diet and activity were controlled and held constant. The rate of appearance (Ra) of glycerol, which indicates lipolytic rates, was similar at baseline and after 4 wk of CLA supplementation at rest (1.87±0.21 and 2.00±0.39 μmol/kg/min, respectively) and during exercise (7.12±0.74 and 6.40±0.99 μmol/kg/min, respectively). Likewise, the Ra of free fatty acids (FFA) was not significantly different after 4 wk of dietary CLA at rest (2.72±0.06 and 2.74±0.12 μmol/kg/min, respectively) or during exercise (6.99±0.40 and 5.88±0.29 μmol/kg/min, respectively). CLA supplementation also had no effect on the percentage of FFA released from lipolysis that were re‐esterified. The apparent rate of FFA re‐esterification was 65.2±4.2% at rest and 32.1±3.44% during exercise. Four weeks of CLA supplementation had no significant effect on fatty acid or glycerol metabolism in healthy, weight‐stable, adult women.
Conjugated linoleic acid supplementation in humans—metabolic effects
Authors: Smedman Annika , Vessby Bengt
Published: November 2006

Supplementation with conjugated linoleic acid (CLA) induces a number of physiological effects in experimental animals, including reduced body fat content, decreased aortic lipid deposition, and improved serum lipid profile. Controlled trials on the effects of CLA in humans have hitherto been scarce. The aim of this study was to evaluate the effects of supplementation with CLA in healthy humans on anthropometric and metabolic variables and on the fatty acid composition of serum lipids and thrombocytes. Fifty‐three healthy men and women, aged 23–63 yr, were randomly assigned to supplementation with CLA (4.2 g/d) or the same amount of olive oil during 12 wk in a double‐blind fashion. The proportion of body fat decreased (−3.8%, P<0.001) in the CLA‐treated group, with a significant difference from the control group (P=0.050). Body weight, body mass index, and sagittal abdominal diameter were unchanged. There were no major differences between the groups in serum lipoproteins, nonesterified fatty acids, plasma insulin, blood glucose, or plasminogen activator inhibitor 1 (PAI‐1). In the CLA group the proportions of stearic, docosatetraenoic, and docosapentaenoic acids increased in serum lipids and thrombocytes, while proportions of palmitic, oleic, and dihomoγ‐linolenic acids decreased, causing a decrease of the estimated Δ‐6 and Δ‐9 and an increase in the Δ‐5 desaturase activities. These results suggest that supplementation with CLA may reduce the proportion of body fat in humans and that CLA affects fatty acid metabolism. No effects on body weight, serum lipids, glucose metabolism, or PAI‐1 were seen.
Serum cholesterol predictive equations with special emphasis on Trans and saturated fatty acids. An analysis from designed controlled studies
Authors: Müller Hanne , Kirkhus Bente , Pedersen Jan I.
Published: November 2006

The effects of dietary trans fatty acids on serum total and low density lipoprotein (LDL) cholesterol have been evaluated by incorporating trans fatty acids into predictive equations and comparing their effects with the effects of the individual saturated fatty acids 12∶0, 14∶0, and 16∶0. Trans fatty acids from partially hydrogenated soybean oil (TRANS V) and fish oil (TRANS F) were included in previously published equations by constrained regression analysis, allowing slight adjustments of existing coefficients. Prior knowledge about the signs and ordering of the regression coefficients was explicitly incorporated into the regression modeling by adding lower and upper bounds to the coefficients. The amounts of oleic acid (18∶1) and polyunsaturated fatty acids (18∶2, 18∶3) were not sufficiently varied in the studies, and the respective regression coefficients were therefore set equal to those found by Yu et al. [Yu, S., Derr, J., Etherton, T.D., and Kris‐Etherton, P.M. (1995) Plasma Cholesterol‐Predictive Equations Demonstrate That Stearic Acid Is Neutral and Monounsaturated Fatty Acids Are Hypocholesterolemic, Am. J. Clin. Nutr. 61, 1129–1139]. Stearic acid (18∶0), considered to be neutral, was not included in the equations. The regression analyses were based on results from four controlled dietary studies with a total of 95 participants and including 10 diets differing in fatty acid composition and with 30–38% of energy (E%) as fat. The analyses resulted in the following equations, where the change in cholesterol is expressed in mmol/L and the change in intake of fatty acids is expressed in E%: Δ Total cholesterol=0.01 Δ(12∶0)+0.12 Δ(14∶0)+0.057 Δ(16∶0)+0.039 Δ(TRANS F)+0.031 Δ(TRANS V)−0.0044 Δ(18∶1)−0.017 Δ(18∶2, 18∶3) and ΔLDL cholesterol =0.01 Δ(12∶0)+0.071 Δ(14∶0)+0.047 Δ(16∶0)+0.043 Δ(TRANS F)+0.025 Δ(TRANS V)−0.0044 Δ(18∶1)−0.017 Δ(18∶2, 18∶3). The regression analyses confirm previous findings that 14∶0 is the most hypercholesterolemic fatty acid and indicate that trans fatty acids are less hypercholesterolemic than the saturated fatty acids 14∶0 and 16∶0. TRANS F may be slightly more hypercholesterolemic than TRANS V or there may be other hypercholesterolemic fatty acids in partially hydrogenated fish oil than those included in the equations. The test set used for validation consisted of 22 data points from seven recently published dietary studies. The equation for total cholesterol showed good prediction ability with a correlation coefficient of 0.981 between observed and predicted values. The equation has been used by the Norwegian food industry in reformulating margarines into more healthful products with reduced content of cholesterol‐raising fatty acids.
Comparative bioavailability of dietary α‐linolenic and docosahexaenoic acids in the growing rat
Authors: Poumès‐Ballihaut Carine , Langelier Bénédicte , Houlier Françoise , Alessandri Jean‐Marc , Durand Georges , Latge Christian , Guesnet Philippe
Published: November 2006

Animal and human studies have indicated that developing mammals fed only α‐linolenic acid (18∶3n−3) have lower docosahexaenoic acid (22∶6n−3) content in brain and tissue phospholipids when compared with mammals fed 18∶3n−3 plus 22∶6n−3. The aim of this study was to test the hypothesis that low bioavailability of dietary 18∶−3 to be converted to 22∶6n−3 could partly explain this difference in fatty acid accretion. For that purpose, we determined the partitioning of dietary 18∶3n−3 and 22∶6n−3 between total n−3 fatty acid body accumulation, excretion, and disappearance (difference between the intake and the sum of total n−3 fatty acids accumulated and excreted). This was assessed using the quantitative method of whole‐body fatty acid balance in growing rats fed the same amount of a 5% fat diet supplying either 18∶3n−3 or 22∶6n−3 at a level of 0.45% of dietary energy (i.e., 200 mg/100 g diet). We found that 58.9% of the total amount of 18∶3n−3 ingested disappeared, 0.4% was excreted in feces, 21.2% accumulated as 18∶3n−3 (50% in total fats and 46% in the carcass‐skin compartment), and 17.2% accumulated as long‐chain derivatives (14% as 22∶6n−3 and 3.2% as 20∶5n−3+22∶5n−3). Similar results were obtained from the docosahexaenoate balance (as % of the total amount ingested): disappearance, 64.5%; excretion, 0.5%; total accumulation, 35% with 30.1% as 22∶6n−3. Thus, rats fed docosahexaenoate accumulated a twofold higher amount of 22∶6n−3, which was mainly deposited in the carcass‐skin compartment (68%). Similar proportions of disappearance of dietary 18∶−3 and 22∶6n−3 lead us to speculate that these two n−3 polyunsaturated fatty acids were β‐oxidized in the same amount.