bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of dietary cholesterol on low density lipoprotein‐receptor, 3‐hydroxy‐3‐methylglutaryl‐CoA reductase, and low density lipoprotein receptor‐related protein mRNA expression in healthy humans
Authors: Boucher Philippe , de Lorgeril Michel , Salen Patricia , Crozier Pierre , Delaye Jacques , Vallon Jean‐Jacques , Geyssant André , Dante Robert
Published: November 2006

We investigated the possibility that dietary cholesterol downregulates the expression of low density lipoprotein (LDL) receptor and 3‐hydroxy‐3‐methylglutaryl (HMG)‐CoA reductase genes of circulating mononuclear cells in vivo in healthy humans. We also studied the variations of the LDL receptor‐related protein (LRP) gene in the same conditions. Dieters (n=5) were submitted to a 4‐d fat restriction (mean cholesterol intake: 6±4 mg/d), followed by a 7‐d cholesterol (a mean of 791±150 mg/d) supplementation. Controls (n=3) did not change their diet. During fat restriction, serum total and LDL cholesterol decreased significantly (P<0.05), and LDL receptor and HMG‐CoA reductase mRNA copy numbers in mononuclear cells increased by 57 and 147%, respectively (P<0.05). After reintroducing cholesterol, serum cholesterol was stable whereas LDL receptor and HMG‐CoA reductase mRNA decreased by 46 and 72% (P<0.05) and LRP mRNA increased by 59% (P<0.005). The changes in LDL receptor and HMG‐CoA reductase mRNA abundance were correlated (r=+0.79, P=0.02) during cholesterol reintroduction as were LDL receptor and LRP mRNA levels, but negatively (r=−0.70, P=0.05). Also, 70% of the variability in LRP mRNA (P<0.005) was explained by dietary cholesterol. Thus, the basic mechanisms regulating cellular cholesterol content, the coordinate feedback repression of genes governing the synthesis and uptake of cholesterol, are operating in vivo in humans. However, serum cholesterol did not increase in response to dietary cholesterol, suggesting that these mechanisms may not play as predominant a role as previously believed in the short‐term control of serum cholesterol in vivo in humans. A new finding is that LRP gene is also sensitive to dietary cholesterol, suggesting that it may participate in the control of serum cholesterol. Further in vivo studies in humans are warranted to explore the molecular mechanisms of the physiological response to dietary cholesterol in humans.
Effect of diet on the fatty acid and molecular species composition of dog retina phospholipids
Authors: Delton‐Vandenbroucke Isabelle , Maude Maureen B. , Chen Huiming , Aguirre Gustavo D. , Acland Gregory M. , Anderson Robert E.
Published: November 2006

Dogs were born to mothers fed commercial diets low or enriched in n‐3 fatty acids and raised on those diets until they were about 50 d old. Retinas were removed, lipids were extracted, and total phospholipids were anlyzed for fatty acid and molecular species composition. Animals from the low n‐3 group had significantly lower retinal levels of 22∶6n‐3 and higher levels of n‐6 fatty acids, especially 20∶4n‐6 and 22∶5n‐6. There was no difference in the retinal levels of 18∶2n‐6, and only small differences were found in saturated and monounsaturated fatty acids. The most dramatic differences in molecular species occurred in 22∶6n‐3‐22∶6n‐3 (4.7 vs. 0.8%) and 18∶0‐22∶6n‐3 (27.6 vs. 14.4%); total molecular species containing 22∶6n‐3 were significantly lower in the low n‐3 group (45.5 vs. 24.0%). Molecular species containing 20∶4n‐6 and 22∶5n‐6 were greater in the low n‐3 animals (13.0 vs. 25.7%), as were molecular species containing only saturated and monounsaturated fatty acids (40.8 vs. 35.4%). These results show that modest differences in the amount of n‐3 fatty acids in the diets of dogs can have profound effects on the fatty acid and molecular species composition of their retinas.
Phytanic acid α‐hydroxylation by bacterial cytochrome P450
Authors: Matsunaga Isamu , Sumimoto Tatsuo , Kusunose Emi , Ichihara Kosuke
Published: November 2006

Fatty acid α‐hydroxylase, a cytochrome P450 enzyme, from Sphingomonas paucimobilis, utilizes various straight‐chain fatty acids as substrates. We investigated whether a recombinant fatty acid α‐hydroxylase is able to metabolize phytanic acid, a methyl‐branched fatty acid. When phytanic acid was incubated with the recombinant enzyme in the presence of H2O2, a reaction product was detected by gas chromatography, whereas a reaction product was not detected in the absence of H2O2. When a heat‐inactivated enzyme was used, a reaction product was not detected with any concentration of H2O2. Analysis of the methylated product by gas chromatography‐mass spectrometry revealed a fragmentation pattern of 2‐hydroxyphytanic acid methyl ester. By single‐ion monitoring, the mass ion and the characteristic fragmentation ions of 2‐hydroxyphytanic acid methyl ester were detected at the retention time corresponding to the time of the product observed on the gas chromatogram. The Km value for phytanic acid was approximately 50 μM, which was similar to that for myristic acid, although the calculated Vmax for phytanic acid was about 15‐fold lower than that for myristic acid. These results indicate that a bacterial cytochrome P450 is able to oxidize phytanic acid to form 2‐hydroxyphytanic acid.
Inhibition of lipoxygenase 1 by phosphatidylcholine micelles‐bound curcumin
Authors: Began G. , Sudharshan E. , Rao A. G. Appu
Published: November 2006

Curcumin (diferuloyl methane) from rhizomes of Curcuma longa L. binds to phosphatidylcholine (PC) micelles. The binding of curcumin with PC micelles was followed by fluorescence measurements. Curcumin emits at 490 nm with an excitation wavelength of 451 nm after binding to PC‐mixed micelles stabilized with deoxycholate. Curcumin in aqueous solution does not inhibit dioxygenation of fatty acids by Lipoxygenase 1 (LOX1). But, when bound to PC micelles, it inhibits the oxidation of fatty acids. The present study has shown that 8.6 μM of curcumin bound to the PC micelles is required for 50% inhibition of linoleic acid peroxidation. Lineweaver‐Burk plot analysis has indicated that curcumin is a competitive inhibitor of LOX1 with Kl of 1.7 μM for linoleic and 4.3 μM for arachidonic acids, respectively. Based on spectroscopic measurements, we conclude that the inhibition of LOX1 activity by curcumin can be due to binding to active center iron and curcumin after binding to the PC micelles acts as an inhibitor of LOX1.
Chemiluminescent determination of cholesterol hydroperoxides in human erythrocyte membrane
Authors: Adachi Junko , Asano Migiwa , Naito Takeaki , Ueno Yasuhiro , Tatsuno Yoshitsugu
Published: November 2006

A method for separating, detecting, and quantifying cholesterol hydroperoxide (Ch‐OOH) based on extraction, purification by solid‐phase extraction cartridge, high‐performance liquid chromatography with chemiluminescent detection (HPIC‐CI), and liquid chromatography mass spectrometry has been developed for human erythrocyte membrane. We prepared standard compounds of the cholesterol 5α‐, 7α‐, and 7β‐hydroperoxides (Ch 5α‐OOH, Ch 7α‐OOH, and Ch 7β‐OOH). An octyl silica column with methanol/water/acetonitrile 89∶9∶2 (by vol) as eluent was used to determine Ch‐OOH. HPLC‐CL that incorporated cytochrome c and luminol as the post‐column luminescent reagent was used. We also investigated the optimal assay conditions and how to prevent formation of artifact Ch‐OOH. Analysis of erythrocyte membranes from seven healthy volunteers identified Ch 7α‐OOH and Ch 7β‐OOH, but not Ch 5α‐OOH, as commonly occurring components. The respective mean concentrations of Ch 7α‐OOH and Ch 7β‐OOH were 2,5±1.6 and 5A±3.5 pmol/mL blood.
Lymphatic fatty acid absorption profile during 24 hours after administration of triglycerides to rats
Authors: Porsgaard Trine , Straarup Ellen Marie , Høy Carl‐Erik
Published: November 2006

In this study we determined in rats the complete 24‐h lymphatic fatty acid profile after administration of either rapeseed oil (RO) or rapeseed oil interesterified with 10∶0 (RO/C10) with special emphasis on the transition from absorptive to postabsorptive phase. Rats were subjected to cannulation of the main mesenteric lymph duct and the next day oils were administered through a gastric feeding tube. Lymph was collected in 1‐h fractions for the following 24 h. The time for maximum lymphatic transport of fatty acids was at 4 h with fast changes in fatty acid composition from the fatty acids of endogenous origin to those of the administered oils. Seven to eight hours after administration the transport was significantly lower than maximum, indicating the change from absorptive to postabsorptive phase. At 24 h after administration of either oil the transport of total fatty acids, palmitic acid (16∶0), and linoleic acid (18∶2n−6) together with oleic acid (18∶1n−9) after RO had not returned to the transport at baseline. In contrast, the transport of decanoic acid (10∶0) and α‐linolenic acid (18∶3n−3) returned to baseline values between 12 and 15 h. This indicated that the absorption of purely exogenous fatty acids (illustrated by 10∶0 and 18∶3n−3) was complete at 15 h and that the fatty acids transported between 15 and 24 h were derived mostly from endogenous stores.
Dietary menhaden, seal, and corn oils differentially affect lipid and Ex vivo eicosanoid and thiobarbituric acid‐reactive substances generation in the guinea pig
Authors: Murphy M. G. , Wright V. , Scott J. , Timmins A. , Ackman R. G.
Published: November 2006

This investigation was carried out to characterize the effects of specific dietary marine oils on tissue and plasma fatty acids and their capacity to generate metabolites (prostanoids, lipid peroxides). Young male guinea pigs were fed nonpurified diet (NP), or NP supplemented (10%, w/w) with menhaden fish oil (MO), harp seal oil (SLO), or corn oil (CO, control diet) for 23 to 28 d. Only the plasma showed significant n−3 polyunsaturated fatty acid (PUFA)‐induced reductions in triacylglycerol (TAG) or total cholesterol concentration. Proportions of total n−3 PUFA in organs and plasma were elevated significantly in both MO and SLO dietary groups (relative to CO), and in all TAG fractions levels were significantly higher in MO‐than SLO‐fed animals. The two marine oil groups differed in their patterns of incorporation of eicosapentaenoic acid (EPA). In guinea pigs fed MO, the highest levels of EPA were in the plasma TAG, whereas in SLO‐fed animals, maximal incorporation of EPA was in the heart polar lipids (PL). In both marine oil groups, the greatest increases in both docosahexaenoic acid (22∶6n−3, DHA) and docosapentaenoic acid (22∶5n−3, DPA) relative to the CO group, were in plasma TAG, although the highest proportions of DHA and DPA were in liver PL and heart TAG, respectively. In comparing the MO and SLO groups, the greatest difference in levels of DHA was in heart TAG (MO>SLO, P<0.005), and in levels of DPA was in heart PL (SLO>MO, P<0.0001). The only significant reduction in proportions of the major n−6 PUFA, arachidonic acid (AA), was in the heart PL of the SLO group (SLO>MO=CO, P<0.005). Marine oil feeding altered ex vivo generation of several prostanoid metabolites of AA, significantly decreasing thromboxane A2 synthesis in homogenates of hearts and livers of guinea pigs fed MO and SLO, respectively (P<0.04 for both, relative to CO). Lipid peroxides were elevated to similar levels in MO‐ and SLO‐fed animals in plasma, liver, and adipose tissue, but not in heart preparations. This study has shown that guinea pigs respond to dietary marine oils with increased organ and plasma n−3 PUFA, and changes in potential synthesis of metabolites. They also appear to respond to n−3 PUFA‐enriched diets in a manner that is different from that of rats.
Brain development and assessing the supply of polyunsaturated fatty acid
Authors: Clandinin M. T.
Published: November 2006

Membrane lipids are necessary for structure and function of the developing nervous system. Rapid synthesis of brain tissue occurs during the last trimester of development of the human brain and the early postnatal weeks. This synthesis of brain structure involves the formation of complex lipids, many of which contain significant quantities of chain‐elongated desaturated homologs of essential fatty acids. The present report discusses the implications of change in nutritional status on processes of brain development and metabolic events that involve lipids.
Neonatal polyunsaturated fatty acid metabolism
Authors: Innis Sheila M. , Sprecher Howard , Hachey David , Edmond John , Anderson Robert E.
Published: November 2006

The importance of n−6 and n−3 polyunsaturated fatty acids (PUFA) in neonatal development, particularly with respect to the developing brain and retina, is well known. This review combines recent information from basic science and clinical studies to highlight recent advances in knowledge on PUFA metabolism and areas where research is still needed on infant n−6 and n−3 fatty acid requirements. Animal, cell culture, and infant studies are consistent in demonstrating that synthesis of 22∶6n−3 involves C24 PUFA and that the amounts of 18∶2n−6 and 18∶3n−3 influence PUFA metabolism. Studies to show that addition of n−6 fatty acids beyond Δ6‐desaturase alters n−6 fatty acid metabolism with no marked increase in tissue 20∶4n−6 illustrate the limitations of analyses of tissue fatty acid compositions as an approach to study the effects of diet on fatty acid metabolism. New information to show highly selective pathways for n−6 and n−3 fatty acid uptake in brain, and efficient path‐ways for conservation of 22∶6n−3 in retina emphasizes the differences in PUFA metabolism among different tissues and the unique features which allow the brain and retina to accumulate and maintain high concentrations of n−3 fatty acids. Further elucidation of the Δ6‐desaturases involved in 24∶5n−6 and 22∶6n−3 synthesis; the regulation of fatty acid movement between the endoplasmic reticulum and peroxisomes; partitioning to acylation, desaturation and oxidation; and the effects of dietary and hormonal factors on these pathways is needed for greater understanding of neonatal PUFA metabolism.
Assessment of long‐chain polyunsaturated fatty acid nutritional supplementation on infant neurobehavioral development and visual acuity
Authors: Jacobson Sandra W.
Published: November 2006

The aims of this paper are (i) to consider how best to examine effects of long‐chain polyunsaturated fatty acid nutritional supplementation or deficiency on infant neurobehavioral development, after controlling for other factors that might influence outcome, including maternal demographic, intellectual, and personality characteristics, and (ii) to present new findings on the relation between visual acuity and processing speed and the effects of prenatal alcohol exposure and visual acuity on infant information processing. The following topics are also addressed: (i) breastfeeding and intelligence, (ii) criteria for the selection and control of potential confounding variables, and (iii) new infant information processing measures.
Polyunsaturated fatty acid status and neurodevelopment: A summary and critical analysis of the literature
Authors: Carlson Susan E. , Neuringer Martha
Published: November 2006

The rationale for randomized trials designed to measure the effects of variable docosahexaenoic acid (DHA) status on neurodevelopment in human infants came from earlier studies of neurodevelopment in animals that were deficient in DHA owing to diets low in α‐linolenic acid. The session on neurodevelopment looked at the results of these animal studies and discussed outcomes that appear to be analogous in human infants with variable DHA status. Presentations focused mainly on measures of development that may be attributed to more specific developmental domains (e.g., visual attention, recognition memory, problem‐solving), some of which have been shown to be affected by long‐chain polyunsaturated fatty acid (LCPUFA) status. This paper derives from discussions that took place during the session and reviews subsequent developments in this area. Although more difficult to interpret, global measures of infant development (e.g., the Bayley Scales of Infant Development, and Brunet‐Lezine) can only suggest a relationship to specific developmental domains, but they have been applied in some randomized trials of LCPUFA and infant development. Those results are also summarized here.
Polyunsaturated fatty acids and infant visual development: A critical appraisal of randomized clinical trials
Authors: Gibson Robert A. , Makrides Maria
Published: November 2006

At the Consensus and Controversies Conference held in Barcelona in November 1996, one of the sessions focused on an evaluation of the effects of dietary polyunsaturated fatty acids (PUFA) on infant visual development. The intervention trials in preterm and term infants were reviewed and discussed in detail. Results of these trials, particularly those in term infants, were inconsistent; much discussion occurred concerning the causes of these diverse results. We attempt to reflect, rather than report exactly, the discussion relating to these issues and address the clinical trials according to recently published guidelines for conduct and reporting of randomized clinical trials (RCT). Compared with these recent guidelines, the published papers of RCT involving PUFA and visual function are often incomplete, making it difficult to assess if we can have a high degree of confidence in the reported effects (or lack of effects). Despite this, valuable data relating to the effect of diet on the visual development of infants were obtained. Our evaluation of the trials to date suggests that the definitive answer to the degree to which dietary long‐chain PUFA is likely to influence visual development may only be resolved with impeccably conducted RCT.
Long‐chain polyunsaturated fatty acids and eicosanoids in infants‐physiological and pathophysiological aspects and open questions
Authors: Sellmayer Alois , Koletzko Berthold
Published: November 2006

Eicosanoids are highly active lipid mediators in physiologic and pathologic processes, with their effects ranging from cytoprotection and vasoactivity to modulation of inflammatory and proliferative reactions. Generation of eicosanoids can be affected by changes in the pools of their precursors, the long‐chain polyunsaturated fatty acids (LCPUFA). Thus, dietary interventions such as supplementation of infant formula with specific n−3 and n−6 LCPUFA will alter formation as well as activity of the eicosanoids produced. This report summarizes the results and discussion of the workshop on “Eicosanoids and Polyunsaturated Fatty Acids in Infants”. The intention of the workshop organizers was to give an overview of the role of eicosanoids in physiological and pathophysiological processes in infants, to discuss the implications that an increased n−3 and n−6 LCPUFA intake may have on eicosanoid genration, and to point out open questions and controversies for future research.
Long‐chain polyunsaturated fatty acids in diets for infants: Choices for recommending and regulating bodies and for manufacturers of dietary products
Authors: Koletzko Berthold , Sinclair Andy
Published: November 2006

While the scientific evaluation of the physiologic effects, potential benefits, and risks of dietary preformed long‐chain polyunsaturated fatty acids (LCPUFA) for infants have been discussed elsewhere, this manuscript addresses some of the resulting consequences and challenges of interpreting the available knowledge from the perspective of recommending and regulating bodies, and of manufacturers of dietary products and their ingredient materials. Traditionally human milk composition has served as a reference point for infant formula design. With respect to the use of LCPUFA in infant formula, much more emphasis than ever before invested for any other group of micronutrients has been put on clinical studies investigating the potential advantages and disadvantages of LCPUFA in infant foods, including growth, safety aspects, and a variety of other outcome measures.
Pharmacokinetic advantages of a newly developed tacrolimus oil‐in‐water‐type emulsion via the enteral route
Authors: Uno Takeji , Kazui Teruhisa , Suzuki Yoshinari , Hashimoto Hisakuni , Suzuki Koichi , Muhammad Bashar A. H.
Published: November 2006

We developed an oleic acid oil‐in‐water (o/w)‐type emulsion of a new tacrolimus formulation that presented an improvement in the delivery of the drug for oral absorption. This investigation was undertaken to assess a sustained release drug delivery system and selective drug transfer into the lymphatic system. The whole blood concentration profiles after oral administration at a dose of 2mg/kg and bone marrow, spleen, liver, lung, small intestine, kidney, brain, and whole blood distribution after oral administration at a dose of 1 mg/kg of o/w emulsion formulation of tacrolimus (O/W group) were compared with those of commercially available formulation (T group) in the rat. The mean diameter of the o/w emulsion droplets was 0.47 μm immediately after preparation. The tacrolimus entrapping efficiency of o/w emulsion was 71.3+5.0% in 12 h and did not change for 2 d. The area under the whole blood concentration‐time curve (AUC) in the O/W group was significantly higher (P<0.01) than that in the I group. In contrast, the values of constant elimination rate and total clearance in the O/W group were significantly lower (P<0.01) than those in the T group, with a comparative bioavailability of 115.9%. The tissue concentration of tacrolimus in the O/W group was significantly higher levels in the bone marrow, spleen, liver, lung, and small intestine, and significantly lower in the brain and kidney, relative to the T group. The o/w emulsion of tacrolimus may be an improved dosage form via the enteral route.
Susceptibility of serum lipids to copper‐induced peroxidation correlates with the level of high density lipoprotein cholesterol
Authors: Shimonov M. , Pinchuk I. , Bor A. , Beigel I. , Fainaru M. , Rubin M. , Lichtenberg D.
Published: November 2006

As a first step in evaluating the significance of our recently developed method of monitoring the kinetics of copper‐induced oxidation in unfractionated serum, we recorded the kinetics of lipid oxidation in the sera of 62 hyperlipidemic patients and analyzed the correlation between oxidation and lipid composition of the sera [high density lipoprotein (HDL) cholesterol, low density lipoprotein (LDL) cholesterol, and triglycerides]. We used six factors to characterize the kinetics of oxidation, namely, the maximal absorbance of oxidation products (ODmax), the maximal rate of their production (Vmax), and the time at which the rate was maximal (tmax) at two wave‐lengths (245 nm, where 7‐ketocholesterol and conjugated dienic hydroperoxides absorb intensely, and 268 nm, where the absorbance is mostly due to dienals). The major conclusions of our analyses are that: (i) Both ODmax and Vmax correlate positively with the sum of concentrations of the major oxidizable lipids, cholesterol, and cholesteryl esters. (ii). The value of tmax, which is a measure of the lag preceding oxidation and therefore reflects the resistance of the serum lipids to copper‐induced oxidation, exhibits a negative correlation with HDL cholesterol. Although this finding accords with the observation of shorter lags for HDL than for LDL, it is apparently inconsistent with the role of HDL as an antirisk factor in coronary heart diseases.
Fatty acid composition of the adipose tissue and yolk lipids of a bird with a marine‐based diet, the emperor penguin (Aptenodytes forsteri)
Authors: Speake Brian K. , Decrock Frederic , Surai Peter F. , Groscolas René
Published: November 2006

The emperor penguin (Aptenodytes forsteri) is an Antarctic seabird feeding mainly on fish and therefore has a high dietary intake of n‐3 polyunsaturated fatty acids. The yolk is accumulated in the developing oocyte while the females are fasting, and a large proportion of the fatty acid components of the yolk lipids are derived by mobilization from the female's adipose tissue. The fatty acid composition of the total lipid of the yolk was characterized by high levels of n‐3 polyunsaturated fatty acids. However, it differed in several respects from that of the maternal adipose tissue. For example, the proportions of 14∶0, 16∶1n−7, 20∶1n−9, 22∶1n−9, 20∶5n−3, and 22∶6n−3 were significantly greater in adipose tissue than in yolk. Thus adipose tissue lipids contained 7.6±0.3% and 8.0±0.3% (wt% of total fatty acids; mean ±SE; n=5) of 20∶5n−3 and 22∶6n−3, respectively, whereas the yolk total lipid contained 1.6±0.1 and 5.5±0.3% of these respective fatty acids. The proportions of 16∶0, 18∶0, 18∶1n−9, 18∶2n−6, and 20∶4n−6 were significantly lower in the adipose tissue than in the yolk lipids. The proportions of triacylglycerol, phospholipid, free cholesterol, and cholesteryl ester in the yolk lipid were, respectively, 67.0±0.2, 25.4±0.3, 5.3±0.2, and 1.8±0.2% (wt% of total yolk lipid). The proportions of 20∶4n−6, 20∶5n−3, 22∶5n−3, and 22∶6n−3 were, respectively, 5.7±0.3, 2.8±0.2, 1.4±0.1, and 11.7±0.5% in phospholipid and 0.4±0.0, 1.2±0.1, 0.8±0.1 and 3.6±0.3% in triacylglycerol. About 95% of the total vitamin E in the yolks was in the form of α‐tocopherol with γ‐tocopherol forming the remainder. Two species of carotenoids, one identified as lutein, were present.
Rapid complexing of oxoacylglycerols with amino acids peptides and aminophospholipids
Authors: Kurvinen J. ‐P. , Kuksis A. , Ravandi A. , Sjövall O. , Kallio H.
Published: November 2006

We prepared model Schiff bases from 2‐[9‐oxo]nonanoyl glycerol (2‐MAG‐ALD) and various amino compounds. 2‐MAG‐ALD was obtained by pancreatic lipase hydrolysis of trioleoyl glycerol and reductive ozonolysis of the resulting 2‐monooleoyl glycerol. The reaction products were purified by thin‐layer chromatography. Schiff bases were synthesized in greater than 50% yield by reacting 2‐MAG‐ALD with twofold molar excess of valine, Nα‐acetyl‐l‐lysine methyl ester and the tripeptides glycyl‐glycyl‐glycine, glycyl‐glycyl‐histidine, and glycyl‐histidyl‐lysine in aqueous methanol and with 1‐palmitoyl‐2‐stearoyl glycerophosphoethanolamine (PE) in chloroform.methanol for 16 h at room temperature. Prior to analysis the bases were reduced with sodium cyanoborohydride in methanol for 30 min at 4°C. Reaction products were analyzed by high‐performance liquid chromatography/electrospray ionization/mass spectrometry (HPLC/ESI/MS). Reduced Schiff bases of 2‐MAG‐ALD with PF and amino acids were analyzed by normal‐phase HPLC/ESI/MS and those with peptides by reversed‐phase HPLC/ESI/MS. Single adducts were obtained in all cases and both the α‐amino group of valine and the ε‐amino group of Nα‐acetyl‐l‐lysine methyl ester were reactive. Molecular ions of reaction products were the only detected ions in the negative ionization mode, whereas in the positive ion mode sodiated molecular ions were also detected. The present study suggests that 2‐MAG‐ALD may form Schiff base adducts with amino compounds in other aqueous media, such as the intestinal lumen and in the hydrophobic environment of cell membranes.
Lipoprotein (a) metabolism estimated by nonsteady‐state kinetics
Authors: Parhofer Klaus G. , Demant Thomas , Ritter Michael M. , Geiss H. Christian , Donner Markus , Schwandt Peter
Published: November 2006

Lipoprotein (a) [Lp(a)] is a low‐density lipoprotein (LDL) particle with an additional apolipoprotein named apo(a). The concentration of Lp(a) in plasma is determined to a large extent by the size of the apo(a) isoform. Because elevated Lp(a) concentrations in plasma are associated with risk for premature coronary heart disease it is important to determine whether variations in production or catabolism mediate differences in Lp(a) concentration. We determined metabolic parameters of Lp(a) in 17 patients with heterozygous familial hypercholesterolemia or severe mixed hyperlipidemia by fitting a monoexponential function to the rebound of Lp(a) plasma concentration following LDL‐apheresis. In 8 of those 17 patients this was done twice following two different aphereses. Although this approach allows one to estimate metabolic parameters without the use of a tracer, it requires several major assumptions such as that apheresis itself does not change production or catabolism of Lp(a) and that Lp(a) metabolism can be described by a single compartment. One apheresis decreased Lp(a) concentration by 59.1±8.3%. The fractional catabolic rate (FCR) was 0.16±0.12 d−1 and production rate 6.27±5.26 mg·kg−1·d−1. However, observed (concentration before first apheresis) and predicted steady‐state concentrations differed considerably (more than 20%) in 9 of 17 patients, indicating that not all assumptions were fulfille in all patients. Production rate but not FCR was correlated with Lp(a) plasma concentration (r2=0.43. P=0.004) and molecular weight of apo(a) (r2=0.48, P=0.011), which confirms radiotracer experiments showing that variations in Lp(a) plasma concentrations are due to differences in production not catabolism. When parameters were estimated tiwce in a subgroup of eight patients, satisfactory reproducibility was observed in six patients. Although parameters determined on two occasions correlated well, only FCR was concordant (intraclass correiation coefficient). Thus, despite the limitations arising from the assumptions implicit to this method, metabolic parameters of Lp(a) can be estimated from the rebound of plasma concentration following apheresis.
Metabolism of trans fatty acids by hepatocytes
Authors: Guzmán Manuel , Klein Wil , Gómez del Pulgar Teresa , Geelen Math J. H.
Published: November 2006

The present work was undertaken to study the metabolism of fatty acids with trans double bonds by rat hepatocytes. In liver mitochondria, elaidoyl‐CoA was a poorer substrate for carnitine palmitoyltransferase I (CPT‐I) than oleoyl‐CoA. Likewise, incubation, of hepatocytes with oleic acid produced a more pronounced stimulation of CPT‐I than incubation with trans fatty acids. This was not due to a differential effect of cis and trans fatty acids on acetyl‐CoA carboxylase (ACC) activity and malonyl‐CoA levels. Elaidic acid was metabolized by hepatocytes at a higher rate than oleic acid. Surprisingly, compared to oleic acid, elaidic acid was a better substrate for mitochondrial and, especially, peroxisomal oxidation, but a poorer substrate for cellular and very low density lipoprotein triacylglycerol synthesis. Results thus show that trans fatty acids are preferentially oxidized by hepatic peroxisomes, and that the ACC/malonyl‐CoA/CPT‐I system for coordinate control of fatty acid metabolism is not responsible for the distinct hepatic utilization of cis and trans fatty acids.
Synthesis of a novel lipopeptide with α‐melanocyte‐stimulating hormone peptide ligand and its effect on liposome stability
Authors: Ogawa Yoshikatsu , Kawahara Hidehiko , Yagi Nobuhiro , Kodaka Masato , Tomohiro Takenori , Okada Tomoko , Konakahara Takeo , Okuno Hiroaki
Published: November 2006

Introduction of liposomes into target cells is important for drug delivery systems. For this purpose, the surface of the liposome is equipped with ligand peptides, which may bind to specific receptors on the cell membrane. An artificial novel lipopeptide (MSH‐C4A2) containing the α‐melanocyte‐stimulating hormone (α‐MSH) sequence and two long alkyl chains was designed and synthesized, and the liposome, composed of egg phosphatidylcholine (EPC) and MSH‐C4A2, was prepared. The stability of the liposome was estimated by measuring calcein leakage from the liposome inner phase. The stability of the liposome decreased upon addition of MSH‐A4C2, which seemed to be attributable to the amphiphilic property of the peptide moiety (α‐MSH) of MSH‐A2C4. The stability was, however, recovered fairly well upon addition of cholesterol (Ch) or phosphatidylglycerol (PG). It was concluded therefore that the ternary system, MSH‐C4A2/Ch/EPC or MSH‐C4A2/PG/EPC, is suitable for preparing the functional liposome.
Improved separation of conjugated fatty acid methyl esters by silver ion‐high‐performance liquid chromatography
Authors: Sehat Najibullah , Rickert Rainer , Mossoba Magdi M. , Kramer John K. G. , Yurawecz Martin P. , Roach John A. G. , Adlof Richard O. , Morehouse Kim M. , Fritsche Jan , Eulitz Klaus D. , Steinhart Hans , Ku Yuoh
Published: November 2006

Operating from one to six silver ion‐high‐performance liquid chromatography (Ag+‐HPLC) columns in series progressively improved the resolution of the methyl esters of conjugated linoleic acid (CLA) isomeric mixtures from natural and commercial products. In natural products, the 8 trans, 10 cis‐octadecadienoic (18∶2) acid was resolved from the more abundant 7 trans, 9 cis‐18∶2, and the 10 trans, 12 cis‐18∶2 was separated from the major 9 cis, 11 trans‐18∶2 peak. In addition, both 11 trans, 13 cis‐18∶2 and 11 cis, 13 trans‐18∶2 isomers were found in natural products and were separated; the presence of the latter, 11 cis, 13 trans‐18∶2, was established in commercial CLA preparations. Three Ag+‐HPLC columns in series appeared to be the best compromise to obtain satisfactory resolution of most CLA isomers found in natural products. A single Ag+‐HPLC column in series with one of several normal‐phase columns did not improve the resolution of CLA isomers as compared to that of the former alone. The 20∶2 conjugated fatty acid isomers 11 cis, 13 trans‐20∶2 and 12 trans, 14 cis‐20∶2, which were synthesized by alkali isomerization from 11 cis, 14 cis‐20∶2, eluted in the same region of the Ag+‐HPLC chromatogram just before the corresponding geometric CLA isomers. Therefore, CLA isomers will require isolation based on chain length prior to Ag+‐HPLC separation. The positions of conjugated double bonds in 20∶2 and 18∶2 isomers were established by gas chromatography‐electron ionization mass spectrometry as their 4,4‐dimethyloxazoline derivatives. The double‐bond geometry was determined by gas chromatography‐direct deposition‐Fourier transform infrared spectroscopy and by the Ag+‐HPLC relative elution order.
Fatty acid metabolism in marine fish: Low activity of fatty acyl Δ5 desaturation in gilthead sea bream (Sparus aurata) cells
Authors: Tocher Douglas R. , Ghioni Cristina
Published: November 2006

Marine fish have an absolute dietary requirement for C20and C22highly unsaturated fatty acids. Previous studies using cultured cell lines indicated that underlying this requirement in marine fish was either a deficiency in fatty acyl Δ5 desaturase or C18–20elongase activity. Recent research in turbot cells found low C18–20elongase but high Δ5 desaturase activity. In the present study, the fatty acid desaturase/elongase pathway was investigated in a cell line (SAF‐1) from another carnivorous marine fish, sea bream. The metabolic conversions of a range of radiolabeled polyunsaturated fatty acids that comprised the direct substrates for Δ6 desaturase ([1‐14C]18∶2n−6 and [1‐14C]18∶3n−3), C18–20elongase ([U‐14C]18∶4n−3), Δ5 desaturase ([1‐14C]20∶3n−6 and [1‐14C]20∶5n−3), and C20–22elongase ([1‐14C]20∶4n−6 and [1‐14C]20∶5n−3) were utilized. The results showed that fatty acyl Δ6 desaturase in SAF‐1 cells was highly active and that C18–20elongase and C20–22elongase activities were substantial. A deficiency in the desaturation/elongation pathway was clearly identified at the level of the fatty acyl Δ5 desaturase, which was very low, particularly with 20∶4n−3 as substrate. In comparison, the apparent activities of Δ6 desaturase, C18–20elongase, and C20–22elongase were approximately 94‐, 27‐, and 16‐fold greater than that for Δ5 desaturase toward their respective n−3 polyunsaturated fatty acid substrates. The evidence obtained in the SAF‐1 cell line is consistent with the dietary requirement for C20and C22highly unsaturated fatty acids in the marine fish the sea bream, being primarily due to a deficiency in fatty acid Δ5 desaturase activity.
Screening of lipase inhibitors from marine algae
Authors: Bitou Nozomu , Ninomiya Masayori , Tsujita Takahiro , Okuda Hiromichi
Published: November 2006

The possible presence of an inhibitor of pancreatic lipase (triacylglycerol acylhydrolase, EC 3.1.1.3) was screened in 54 marine algae. An active inhibitor, caulerpenyne, was purified from an extract of Caulerpa taxifolia, using ethyl acetate extraction, followed by successive chromatographies on ODS and silica gel columns. The purified inhibitor was identified by thin‐layer chromatography, infrared and nuclear magnetic resonance spectroscopy. Caulerpenyne competitively inhibited lipase activities using emulsified triolein and dispersed 4‐methylumbelliferyl oleate (4‐MU oleate) as substrates. The concentrations producing 50% inhibition against triolein and 4‐MU oleate hydrolysis were 2 mM and 13 μM, respectively. In vivo, oral administration of corn oil with or without caulerpenyne to rats demonstrated a reduced and delayed peak plasma triacylglycerol concentration with caulerpenyne.
Cross‐influence of membrane polyunsaturated fatty acids and hypoxia‐reoxygenation on α‐ and β‐adrenergic function of rat cardiomyocytes
Authors: Ponsard Blandine , Durot Isabelle , Delerive Philippe , Oudot Fabien , Cordelet Catherine , Grynberg Alain , Athias Pierre
Published: November 2006

The purpose of the present investigation was to determine whether the beneficial effects of polyunsaturated fatty acids (PUFA) may influence ischemia‐reperfusion‐induced alterations of myocardial α‐ and β‐adrenoceptor (α‐AR, β‐AR) responsiveness. This study was carried out using monolayer cultures of neonatal rat ventricular myocytes in a substrate‐free, hypoxia‐reoxygenation model of ischemia. The cardiomyocytes (CM) were incubated during 4 days in media enriched either with n−6 PUFA (arachidonic acid, AA) or with n−3 PUFA (eicosapentaenoic acid, EPA, and docosahexaenoic acid, DHA). The n−6/n−3 ratio in n−3 CM was close to 1.2, compared to 20.1 in n−6 CM. The contractile parameters of n−6 CM and n−3 CM were similar in basal conditions as well as during hypoxia and reoxygenation. In basal conditions, the phospholipid (PL) enrichment with long chain n−3 PUFA resulted in an increased chronotropic response to isoproterenol (ISO) and to phenylephrine (PHE). After posthypoxic reoxygenation, the chronotropic response to β‐AR activation in n−6 CM was significantly enhanced as compared with the control response in normoxia. In opposition, the ISO‐induced rise in frequency in n−3 CM in control normoxia and after reoxygenation was similar. In these n−3 CM, the changes in contractile parameters, which accompanied the chronotropic response, were also similar in reoxygenation and in normoxic periods, although the rise in shortening velocity was slightly increased after reoxygenation. In response to PHE addition, only the chronotropic effect of n−6 CM appeared significantly enhanced after hypoxic treatment. These results suggested that increasing n−3 PUFA in PL reduced the increase in α‐ and β‐AR functional responses observed after hypoxia‐reoxygenation. This effect may partly account for the assumed cardiac protective effect of n−3 PUFA, through the attenuation of the functional response to catecholamines in the ischemic myocardium.
Effects of dietary supplementation of saturated fatty acids and of n−6 or n−3 polyunsaturated fatty acids on plasma and red blood cell membrane phospholipids and deformability in weanling guinea pigs
Authors: Pöschl Johannes M. B. , Paul Karl , Leichsenring Michael , Han Shan R. , Pfisterer Matthias , Bremer Hans J. , Linderkamp Otwin
Published: November 2006

The fatty acid composition of plasma cholesteryl esters, plasma phospholipids, red blood cell (RBC) membrane phosphatidylcholine (corresponding to the outer membrane leaflet), and phosphatidylethanolamine (corresponding to the inner membrane leaflet) was investigated in weanling guinea pigs fed with diets of cacao (saturated fatty acids), sunflower oil [n−6 polyunsaturated fatty acids (PUFA)] or fish oil (n−3 PUFA) for 20 wk. RBC deformation was measured by means of a cell‐transit analyzer (filtration) and a cone‐plate rheoscope. The contents of saturated fatty acids in plasma phospholipids and RBC membrane leaflets were similar in all three groups. Diets with sunflower oil resulted in a high content of linoleic acid in plasma cholesteryl esters and in the outer leaflet of RBC membranes. Fatty acids of fish oil were mainly incorporated in plasma phospholipids and in the inner leaflet of RBC membranes. The arachidonic acid content was high in all groups in the plasma phospholipids and in the inner leaflet. The n−6 and n−3 PUFA were mainly incorporated in the inner leaflet. In all groups the polyunsaturated/saturated fatty acid ratio and the total PUFA content were similar in the inner RBC membrane. The RBC filtration times and the RBC deformation indices were not affected by the dietary treatment.
Dietary supplementation with arachidonic and docosahexaenoic acids has no effect on pulmonary surfactant in artificially reared infant rats
Authors: Yeh Yu‐Yan , Whitelock Kerry Anne , Yeh Shaw‐Mei , Lien Eric L.
Published: November 2006

Despite the potential use of long‐chain polyunsaturated fatty acid (LCPUFA) supplementation to promote growth and neural development of the infant, little is known about potential harmful effects of the supplementation. The present study determined whether supplementation with arachidonic acid (AA) and/or docosahexaenoic acid (DHA) in rat milk formula (RMF) affects saturation of pulmonary surfactant phospholipids (PL). Beginning at 7 d of age, infant rats were artificially fed for 10 d with RMF supplemented with AA at 0, 0.5, and 1.0% of total fatty acid, or supplemented with DHA at 0, 0.5, and 1.0%, or cosupplemented with AA and DHA at levels of 0∶0, 0.5∶0.3, and 1.0∶0.6% of the fat blend. Lung tissue PL contained 43 weight percent palmitate (16∶0) of total fatty acids in infant rats fed the unsupplemented RMF. The supplementation with AA at both 0.5 and 1.0% decreased the weight percentage of 16∶0 and stearate (18∶0), indicating a decrease in saturation of PL. The observed decreases were accompanied by increases in AA and linoleic acid (18∶2n−6). Surfactant phosphatidylcholine (PC) consisted of 71 weight percent 16∶0 in the unsupplemented group, and this highly saturated PC was not altered by the cosupplementation with AA and DHA although there was a slight increase in DHA. Similarly, the cosupplementation did not change fatty acid composition of surfactant PL when compared with the unsupplemented group. The cosupplementation slightly decreased the weight percentage of 16∶0 with a proportional increase in 18∶0 leading to an unchanged weight percentage of total saturated fatty acids. These results suggest that, unlike lung tissue PL, the composition of saturated fatty acids in surfactant PL, particularly PC, is resistant to change by dietary AA and DHA supplementation. This, together with the unchanged concentration of total fatty acids in surfactant PC, indicates that LCPUFA cosupplementation causes no effect on pulmonary surfactant.
Lipophilic aldehydes and related carbonyl compounds in rat and human urine
Authors: Kim Song‐Suk , Gallaher Daniel D. , Csallany A. Saari
Published: November 2006

Rat and human urine samples were analyzed for lipophilic aldehydes and other carbonyl products of lipid peroxidation. The following compounds were identified as their 2,4‐dinitrophenyl hydrazones by cochromatography with pure standards using three solvent systems: butanal, butan‐2‐one, pentan‐2‐one, hex‐2‐enal, hexanal, hepta‐2,4‐dienal, hept‐2‐enal, octanal, non‐2‐enal, deca‐2,4‐dienal, 4‐hydroxyhex‐2‐enal, and 4‐hydroxynon‐2‐enal. In general, fasted rats excreted less of these compounds than fed rats, indicating they were partially of dietary origin or that the endogenous compounds were excreted in a form not susceptible to hydrazone formation. The compounds excreted in human urine were similar to those excreted in rat urine but were present in lower concentrations. Identification of the conjugated forms fo the lipophilic aldehydes and related carbonyl compounds excreted in urine may be a source of information about their reactions in vivo.
Fenofibrate protects lipoproteins from lipid peroxidation: Synergistic interaction with α‐tocopherol
Authors: Chaput Evelyne , Maubrou‐Sanchez Dominique , Bellamy François D. , Edgar Alan D.
Published: November 2006

One of the earliest steps of atherosclerotic plaque formation is an increase of circulating apolipoprotein B‐containing lipoproteins which, after infiltrating the subendothelial space, undergo oxidative modification. Fenofibrate is an effective cholesterol‐ and triglyceride‐lowering agent which has been shown to be beneficial in the treatment of atherosclerosis. Vitamin E, or α‐tocopherol, is a powerful antioxidant which has been shown in a variety of studies to prevent lipoprotein peroxidation. The purpose of the present study was to investigate the effect of fenofibrate treatment, either alone or in combination with α‐tocopherol, in reducing the susceptibility of lipoproteins to oxidative modification. Rats fed a normal diet were treated for up to 27 d with fenofibrate, either alone or in combination with equimolar doses of α‐tocopherol. Combined VLDL (very low density lipoproteins) and LDL (low density lipoproteins) isolated after fenofibrate treatment were more resistant to coppermediated oxidation, as assessed by conjugated diene formation. Lag time was prolonged up to 3.2‐fold, while the maximal rate of diene production was significantly decreased by up to 2.2‐fold. Treatment of rats with α‐tocopherol alone at the selected dose had no significant effect on lag time, while the propagation rate was slightly decreased. Coadministration of fenofibrate with α‐tocopherol prolonged the lag phase to a greater extent than fenofibrate alone, showing a synergistic interaction between the two compounds. Finally, the combination of fenofibrate and α‐tocopherol was significantly more effective in modifying lipoprotein oxidation parameters than what was observed with α‐tocopherol and bezafibrate or gemfibrozil. Thus, in addition to its well‐established effects on lipoprotein concentrations and atherogenic parameters, fenofibrate reduces the susceptibility of VLDL and LDL to oxidative modification and exerts its action synergistically with α‐tocopherol.
Microemulsion of seal oil markedly enhances the transfer of a hydrophobic radiopharmaceutical into acetylated low density lipoprotein
Authors: Xiao Wu , Wang Lili , Davis Philip J. , Liu Hu
Published: November 2006

Four different microemulsions differing in their core lipid component (triolein, canola oil, squalene, or seal oil) and containing 1,3‐dihydroxypropan‐2‐one 1,3‐diiopanoate (DPIP), a potential radioimaging probe, were prepared by means of ultrasonication. The DPIP microemulsions were incubated with acetylated human low density lipoprotein (AcLDL) and the amount of DPIP transferred into AcLDL was examined. The amount of DPIP in the microemulsions expressed as DPIP/oil (w/w) was dependent on the core lipid component of the microemulsion in the order of seal oil (0.19±0.04, mean ±standard deviation) > squalene (0.15±0.02) > canola oil (0.12±0.02) > triolein (0.07±0.004). With the exception of canola oil, all microemulsions were effective in enhancing the transfer of DPIP into Acl DI in comparison with commonly used methods, i.e, direct diffusion and detergent solubilization. DPIP in seal oil resulted in the highest amount of DPIP transferred into AcLDL [309.16±34.82 vs. 203.19±64.51 using squalene and 151.31±28.54 using triolein (DPIP molecules per AcLDL particle)]. For the first time, oil from harp seals, was studied as a major core lipid component of formulating pharmaceutical microemulsions. DPIP in seal oil resulted in the highest transfer of DPIP into AcLDL which is likely due to the highest DPIP concentration found in this microemulsion as well as the high fluidity of seal oil.