Unesterified Fatty Acids Research Articles

Plasma Unesterified Fatty-Acid Profile Is Dramatically and Acutely Changed under Ischemic Stroke in the Mouse Model.

Although plasma biomarkers would facilitate rapid and accurate diagnosis of ischemic stroke for immediate treatment, no such biomarkers have been developed to date. In the present study, we tested our hypothesis that plasma unesterified fatty acids (FFA) are altered at early stages of acute ischemic stroke. Plasma was collected from mice 2 h after the permanent middle cerebral artery occlusion (pMCAo) onset, as well as from sham operated and control animals. After 2 h, pMCAo significantly changed the plasma FFA profile with the most dramatic 2- to 3-fold relative increase in very long n-3 and n-6 FFA including 20:4n-6, 22:4n-6, 22:5n-6, and 22:6n-3. Changes in the plasma FFA profile are consistent with FFA liberation from brain phospholipid hydrolyzed under ischemic insult. These results identify, for the first time, the plasma FFA profile as a potential biomarker for an early ischemic stroke within the therapeutic window for thrombolytic treatment. Further studies are required to confirm its specificity and sensitivity in clinical settings.

Hydrolysis Activity of Pyloric Cecal Enterocytes of Brown Trout (Salmo trutta) toward Monoacylglycerol and Lysophosphatidylcholine.

Some lipid digestion pathways in fish deviate from those in mammals, and many differences may also be species dependent. This report describes a pathway for monoacylglycerol (MAG) and lysophospholipid absorption by intestinal enterocytes in brown trout that may be of significance in salmonids. When culturing primary cells in a medium containing 1- and 2-MAG, we observed a massive hydrolysis of unesterified fatty acids. The hydrolysis activity was retained in the medium even after the removal of the cells. To further characterize these activities, both extracellular and isolated membrane proteins were tested for lipase activity toward triacylglycerol (TAG), diacylglycerol (DAG), MAG, phosphatidylcholine (PtdCho), and lysoPtdCho. In both cases, the main hydrolyzing activity was toward MAG followed by lysoPtdCho with very little activity toward DAG, TAG, or PtdCho. The extracellular and membrane proteins were partially purified by fast protein liquid chromatography and identified by proteomics (liquid chromatography-tandem mass spectrometry) focusing on lipase/hydrolase enzymes. In the membrane protein fraction, the data suggested that MAG was produced as an intermediate in the hydrolysis of lysoPtdCho by either lysophospholipase C or lysophospholipase D activity. Both abhydrolase-domain-containing protein 6 and abhydrolase-domain-containing protein 12 were identified in the membrane protein and they could be responsible for the hydrolysis of MAG. In the culture medium, low-peptide matches were found for ABHD6 and phospholipases and further studies are needed. In summary, trout enterocytes are capable of hydrolyzing MAG and lysoPtdCho. The enzymes are both extracellular and membrane bound. The pathways may be of significance during lipid absorption in fish lacking a 1,3 specific pancreatic lipase.

Natural Abundance Carbon Isotopic Analysis Indicates the Equal Contribution of Local Synthesis and Plasma Uptake to Palmitate Levels in the Mouse Brain.

Saturated fatty acids are the most abundant fatty acids in the brain, however, there has been some debate regarding the ability of intact dietary saturated fatty acids to be incorporated into the brain. In the present study, we use compound specific isotope analysis to measure the natural abundance carbon isotopic signature of brain, liver, and blood palmitic acid (PAM) and compare it to the dietary PAM and sugar isotopic signatures to calculate the relative contribution of both the incorporation of intact and endogenously synthesized PAM to these pools. Mice were equilibrated to the study diet, and extracted fatty acids were analyzed with gas chromatography isotope ratio mass spectrometry to determine the carbon isotopic signature of PAM (δ13 CPAM ). Liver, serum total, and serum unesterified fatty acid δ13 CPAM ranged between -20.6 and -21.1 mUr and were approximately 8.5 mUr more enriched in 13 C when compared to the dietary PAM signature. Brain δ13 CPAM was found to be more enriched than liver or blood pools (-16.7 ± 0.2 mUr, mean ± SD). Two end-member-mixed modeling using the carbon isotopic signature of dietary PAM and dietary sugars determined the contribution of synthesis to the total tissue PAM pool to range between 44% and 48%. This suggests that endogenous synthesis and dietary PAM are near equal contributors to brain, liver, and blood PAM pools. In conclusion, our data provide evidence that brain PAM levels are maintained by both local endogenous synthesis and through the uptake of intact PAM from the blood.

Identifying Alzheimer's Disease Biomarkers by Analyzing Fatty Acids in Cerebrospinal Fluid and Urine

Although fatty acid oxidation is associated with Alzheimer's disease (AD) pathology, no links have been established between brain lipids and excreted oxidized products. We hypothesize that oxidation of brain polyunsaturated fatty acids (PUFA) can generate dicarboxylic acids (DCA) excreted in urine by AD subjects at different rates compared with cognitively healthy (CH) subjects. Furthermore, this trend can be extended to differentiate CH subjects with normal cerebrospinal fluid (CSF) Aβ42/tau ratios (CH‐NAT) and CH subjects with pathological CSF Aβ42/tau ratios (CH‐PAT).Subjects > 70 years were classified as CH (n=64) or AD (n=26) after neuropsychological assessment. CSF Aβ42 and Tau levels were determined using an ELISA‐based method and a logistic regression of Aβ42/tau ratios used to classify CH‐NAT and CH‐PAT. CSF was fractionated and PUFA levels quantified in supernatant fluid (SF), nanoparticles (NP), and unesterified fatty acid (UFA). DCA was derivatized to pentafluorobenzyl ester, and quantified using gas chromatography and isotope dilution negative ion chemical ionization mass spectrometry. PUFA data is expressed as a percentage of fatty acids detected in CSF fractions while DCA is calculated as a percentage of 7 DCAs (C4–C10) in urine. Links between urinary DCAs and CSF PUFAs were determined using Spearman's ranked correlation.C10 DCA negatively correlated with 6 of 8 PUFAs in SF from CH and also negatively correlated with C20:3n‐3 and C22:6n‐3 in SF from CH‐NAT. In contrast, C9 DCA negatively correlated with 7 of 8 PUFAs in SF from AD. C6 and C8 DCAs positively correlated with SF C18:3n‐3 and C20:3n‐3 in AD, respectively, while C6 DCA negatively correlated with SF C18:2n‐6 from CH‐NAT. C4 DCA negatively correlated with C18:2n‐6, C20:4n‐6, and C22:6n‐3 in SF from CH‐PAT, while C7 DCA positively correlated with C20:4n‐6 in SF from CH‐PAT. In the NP fraction of CH, C4 DCA positively correlated with C20:2n‐6, C20:3n‐3, C20:5n‐3, and C22:5n‐3 PUFAs, while C8 DCA negatively correlated with C20:5n‐3. Only C9 DCA positively correlated with C20:4n‐6 in AD NP fractions. Interestingly, no correlations were found in the NP fraction from CH‐NAT. However, C8 DCA negatively correlated with NP C20:3n‐3, C20:5n‐3, and C22:5n‐3 and C4 DCA positively correlated with NP C20:5n‐3 from CH‐PAT. For UFA of CH, C6 DCA negatively correlated with C20:2n‐6, C20:3n‐3, and C22:6n‐3, while C5 and C7 DCAs positively correlated with homo‐γ‐C20:3n‐6 and C18:2n‐6, respectively. For UFA of CH‐NAT, C4 DCA positively correlated with homo‐γ‐C20:3n‐6, C5 and C8 DCAs negatively correlated with homo‐γ‐C20:3n‐6, and C7 DCA negatively correlated with C18:2n‐6. C5 DCA positively correlated with C18:2n‐6 in UFA from CH‐PAT. C8 DCA positively correlated with unesterified C22:6n‐3, while C9 DCA negatively correlated with unesterified C20:5n‐3 in AD subjects.Differential correlation of urinary DCAs with CSF PUFAs in clinical groups suggests a link with AD pathology. PUFAs and DCAs that segregate CH‐NAT from CH‐PAT are potential biomarkers of early AD.Support or Funding InformationL.K. Whittier and the Helen Posthuma FoundationsThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Rat Small Intestinal Mucosal Epithelial Cells Absorb Dietary 1,3-Diacylglycerol Via Phosphatidic Acid Pathways.

Compared with triacylglycerol (TAG), dietary 1,3-diacylglycerol (1,3-DAG) is associated with reduced serum lipid and glucose levels. We investigated the metabolism of 1,3-DAG by assaying its intermediate metabolites during digestion and absorption in the rat small intestine. After gavage with TAG emulsion, TAG was digested mainly to 2-monoacylglycerol (2-MAG) and unesterified fatty acid (FFA) in the rat small intestinal lumen. 2-MAG was directly absorbed into the small intestinal epithelial cells and esterified to 1,2(2,3)-DAG, and further esterified to TAG. After gavage with 1,3-DAG emulsion, 1,3-DAG was digested mainly to 1(3)-MAG and FFA in the rat small intestinal lumen with subsequent significant increase of 1-MAG and 1,3-DAG concentrations in small intestinal mucosal epithelial cells, and the 2-MAG, 1,2(2,3)-DAG, and TAG concentrations in mucosal epithelial cells were not significantly different after 1,3-DAG than after TAG gavage, suggesting that the metabolic pathway of 1,3-DAG is different from that of TAG. In intestinal mucosal epithelial cells, we further assayed enzyme levels and gene expression of proteins in the phosphatidic acid (PtdOH) pathway. The glycerol kinase, phosphatidate phosphatase, and diacylglycerol acyltransferase-2 expression and the relative expression of mRNA of enzymes were significantly increased in the 1,3-DAG group compared with the TAG group, suggesting that TAG synthesis from dietary 1,3-DAG was mainly via PtdOH pathways, which may partially account for the effect of dietary DAG on postprandial serum TAG.

Preparation of High Purity Δ5-Olefinic Acids from Pine Nut Oil via Repeated Lipase-Catalyzed Esterification.

Δ5-Olefinic acids have been characterized in gymnosperm plants and have been reported to have several biological health benefits. Δ5-Olefinic acids from pine nut oil were effectively concentrated by repeated lipase-catalyzed esterification. The pine nut oil contained three major Δ5-olefinic acids, namely taxoleic acid (C18:2 Δ5,9), pinolenic acid (C18:3 Δ5,9,12), and sciadonic acid (C20:3 Δ5,11,14). The fatty acids present in pine nut oil were selectively esterified with ethanol using Lipozyme RM IM from Rhizomucor miehei as a biocatalyst. The Δ5-olefinic acids were concentrated in the unesterified fatty acid fraction. The optimum molar ratio of the substrates (fatty acid:ethanol), temperature, the enzyme loading, and the reaction time were 1:7, 25°C, 5% of total substrate weight, and 6 h, respectively. There was no significant effect in the concentration of Δ5-olefinic acids when water was added in the reaction mixture. The same protocol and optimum conditions were employed for two times repeated lipase-catalyzed esterifications. In first lipase-catalyzed esterification, the Δ5-olefinic acids content in the pine nut oil increased from 17 mol% to 51 mol% with a yield of 40 mol%. In a second lipase-catalyzed esterification, with the Δ5-olefinic acids-concentrated fatty acids obtained from the first reaction as the substrate, the Δ5-olefinic acids content increased to 86 mol% with a yield of 15 mol%. Finally, a maximum Δ5-olefinic acids content of ca. 96 mol% with a yield of 6 mol% was obtained via a third lipase-catalyzed esterification.

Microsomal triglyceride transfer protein contributes to lipid droplet maturation in adipocytes.

Previous studies in our laboratory have established the presence of MTP in both white and brown adipose tissue in mice as well as in 3T3-L1 cells. Additional studies demonstrated an increase in MTP levels as 3T3-L1 cells differentiate into adipocytes concurrent with the movement of MTP from the juxtanuclear region of the cell to the surface of lipid droplets. This suggested a role for MTP in lipid droplet biogenesis and/or maturation. To probe the role of MTP in adipocytes, we used a Cre-Lox approach with aP2-Cre and Adipoq-Cre recombinase transgenic mice to knock down MTP expression in brown and white fat of mice. MTP expression was reduced approximately 55% in white fat and 65–80% in brown fat. Reducing MTP expression in adipose tissue had no effect on weight gain or body composition, whether the mice were fed a regular rodent or high fat diet. In addition, serum lipids and unesterified fatty acid levels were not altered in the knockdown mice. Importantly, decreased MTP expression in adipose tissue was associated with smaller lipid droplets in brown fat and smaller adipocytes in white fat. These results combined with our previous studies showing MTP lipid transfer activity is not necessary for lipid droplet initiation or growth in the early stages of differentiation, suggest that a structural feature of the MTP protein is important in lipid droplet maturation. We conclude that MTP protein plays a critical role in lipid droplet maturation, but does not regulate total body fat accumulation.

Fatty acid amide hydrolase (FAAH) regulates hypercapnia/ischemia-induced increases in n-acylethanolamines in mouse brain.

N-acylethanolamines (NAEs) are endogenous lipid ligands for several receptors including cannabinoid receptors and peroxisome proliferator-activated receptor-alpha (PPAR-α), which regulate numerous physiological functions. Fatty acid amide hydrolase (FAAH) is largely responsible for the degradation of NAEs. However, at high concentrations of ethanolamines and unesterified fatty acids, FAAH can also catalyze the reverse reaction, producing NAEs. Several brain insults such as ischemia and hypoxia increase brain unesterified fatty acids. Because FAAH can catalyze the synthesis of NAE, we aimed to test whether FAAH was necessary for CO2 -induced hypercapnia/ischemia increases in NAE. To test this, we examined levels of NAEs, 1- and 2-arachidonoylglycerols as well as their corresponding fatty acid precursors in wild-type and mice lacking FAAH (FAAH-KO) with three Kill methods: (i) head-focused, high-energy microwave irradiation (microwave), (ii) 5min CO2 followed by microwave irradiation (CO2 + microwave), and (iii) 5min CO2 only (CO2 ). Both CO2 -induced groups increased, to a similar extent, brain levels of unesterified oleic, arachidonic, and docosahexaenoic acid and 1- and 2-arachidonoylglycerols compared to the microwave group in both wild-type and FAAH-KO mice. Oleoylethanolamide (OEA), arachidonoylethanolamide (AEA), and docosahexaenoylethanolamide (DHEA) levels were about 8-, 7-, and 2.5-fold higher, respectively, in the FAAH-KO mice compared with the wild-type mice. Interestingly, the concentrations of OEA, AEA, and DHEA increased 2.5- to 4-fold in response to both CO2 -induced groups in wild-type mice, but DHEA increased only in the CO2 group in FAAH-KO mice. Our study demonstrates that FAAH is necessary for CO2 - induced increases in OEA and AEA but not DHEA. Targeting brain FAAH could impair the production of NAEs in response to brain injuries.

Fundamental studies of adrenal retinoid-X-receptor: Protein isoform, tissue expression, subcellular distribution, and ligand availability

Adrenal gland reportedly expresses many nuclear receptors that are known to heterodimerize with retinoid-X-receptor (RXR) for functions, but the information regarding the glandular RXR is not adequate. Studies of rat adrenal homogenate by Western blotting revealed three RXR proteins: RXRα (55kDa), RXRβ (47kDa) and RXR (56kDa). RXRγ was not detectable. After fractionation, RXRα was almost exclusively localized in the nuclear fraction. In comparison, substantial portions of RXRβ and RXR were found in both nuclear and post-nuclear particle fractions, suggesting genomic and non-genomic functions. Cells immunostained for RXRα were primarily localized in zona fasciculata (ZF) and medulla, although some stained cells were found in zona glomerulosa (ZG) and zona reticularis (ZR). In contrast, cells immunostained for RXRβ were concentrated principally in ZG, although some stained cells were seen in ZR, ZF, and medulla (in descending order, qualitatively). Analysis of adrenal lipid extracts by LC/MS did not detect 9-cis-retinoic acid (a potent RXR-ligand) but identified all-trans retinoic acid. Since C20 and C22 polyunsaturated fatty acids (PUFAs) can also activate RXR, subcellular availabilities of unesterified fatty acids were investigated by GC/MS. As results, arachidonic acid (C20:4), adrenic acid (C22:4), docosapentaenoic acid (C22:5), and cervonic acid (C22:6) were detected in the lipids extracted from each subcellular fraction. Thus, the RXR-agonizing PUFAs are available in all the main subcellular compartments considerably. The present findings not only shed light on the adrenal network of RXRs but also provide baseline information for further investigations of RXR heterodimers in the regulation of adrenal steroidogenesis.

The phylogenetic theory of general pathology. The development of seven biological functions, seven specific ones and etiological factors of metabolic epidemics, millions years' common pathogenesis and basics of prevention.

The clearer realization is coming that in general biology, medicine, historical science, in biologic phylogenetic anamnesis of Homo sapiens a task exists only one by its significance and unresolved still: to establish historical succession of becoming of specific etiologic factors of every metabolic epidemic and to understand becoming of millions years' common pathogenesis of all metabolic pandemics. The carnivorous feeding by ocean, herbivorous feeding of ancestors of rodents and Homo sapiens by dry land; misusing carnivorous food by phylogenetically herbivorous human during last centuries, disorder of biological function of trophology, biological reaction of exotrophy, pathology of biologic functions of adaptation and endoecology, features of cognitive biological function formed etiological factors of atherosclerosis and atheromatosis. The abnormalities of biological reaction metabolism↔micro-circulation; discrepancy of mechanisms of regulation of biological reaction at 2d and 3d levels of relative biological perfection in vivo, disorder of biological function of adaptation, biological reaction of compensation formed etiological factors of metabolic arterial hypertension. The synthesis of fatty acids in phylogenesis millions of years before of glucose, preference of cells to absorb fatty acids instead of glucose; previously in phylogenesis effect of hyperglycemia, glucagon and late function of insulin formed priority of metabolism of fatty acids in energetics of organisms and glucose only in the second instance. The formation in phylogenesis of methodological mode of biological subordination in functioning of humoral mediators, incapability of insulin late in phylogenesis of blocking adaptive action of humoral mediators earlier in phylogenesis, especially in visceral fatty tissue form etiological factors of resistance to insulin. The functional limitation of cognitive biological function, difficulties in maintaining unity of internal medium of organism and effects of aphysiologic factors of external medium produces necessity of completing cognitive biological function with activation of biological reaction of apoptosis and autophagy. This occurrence forms etiologic factors of metabolic syndrome - a local pathology of early, visceral, limited in numbers of cells of pool of insulin-independent visceral fatty tissue. The inconsistency of cognitive biological function, necessity of correcting it by more effective biological function of intellect, role of insulin in energy support of new biological function - locomotion, formation of unlimited in numbers of cells а pool late in phylogenesis of insulin-dependent subcutaneous adipocytes, formed etiological factors of obesity. The biological function of depositing of fatty acids in phylogenesis in vivo is characterized by etiological dependence: depositing of fatty acids occurs in the form of non-polar triglycerides and releasing into intercellular medium occurs only in form of polar unesterified fatty acids. The features of induction with substrate, formation of positioning isoforms of fatty acids, impossibility of hydrolyzing them at effecting of hormone-dependent lipase compel to eliminate aphysiologic triglycerides from liver together with hepatocytes implementing biological reactions of apoptosis and autophagy. They become etiological factors of non-alcoholic fatty disease of liver; these are aphysiologic positioning iusoforms of triglycerides as palmitoyl-palmitol-palmitate and stearyl-stearyl-stearate. The formation of endogenous hyperuricemia in phylogenesis was initiated by 2 mutations. The first one - a gene of ascorbic acid "minus" deprived Homo sapiens of synthesis of hydrophilic acceptor of active forms of oxygen. The second one - a gene of uricase "minus" blocked synthesis of allantoin but provided a possibility of re-absorbing uric acid from a pool of primary urine and use it in vivo as an acceptor of active forms of oxygen instead of ascorbic acid under realization of biological function of endoecology,biologic reaction of inflammation.

The nicotinic acid as an inhibitor of lipolysis in the phylogenetically early visceral cells; insulin also blocks hydrolysis of triglycerides in the phylogenetically late adipocytes.

It is valid to consider effect of nicotinic acid as an insulin-mimetic one. The uniformity of biologic effect of exogenous nicotinic acid and endogenous insulin permits to become aware that a) the hypo-lipidemic activity of insulin, inhibition of lipolysis in phylogenetically late insulin-dependent adipocytes and decreasing of content of unesterified fatty acids in blood plasma are considered as a basis of hypoglycemic effect of insulin; b) nicotinic acid similar to insulin blocks lipolysis too but in hormoneindependent visceral fatty cells. The counter-insular effect is manifested in vivo by exogenous and endogenous palmitic saturated fatty acid by force of physical chemical characteristics. The biological role of insulin consists in regulation of metabolism of fatty acids mainly unesterified fatty acids and in absorption of glucose by all insulin-dependent cells. It is supposed that contractile cells (myocytes and cardiomyocytes) cumulate glycogen for implementing glucose as a substrate in synthesis in situ de novo of ῲ-9 oleic mono-saturated fatty acid. The insulin initiates synthesis because mitochondria process this mono-saturated fatty to β-oxidation with the highest constant of reaction velocity. This is conditioned by physical chemical characteristics of oleic mono-saturated fatty acid, positioning of double bond in the chain of fatty acid; this ensures maximal efficiency of ATP gaining. In phylogenesis, the low efficient palmitic alternative of metabolism of fatty acids is formed the earliest. At the later stages of phylogenesis the cells, under becoming of motion function, worked out more efficient alternative of ATP synthesis from exogenous ῲ-9 oleic monosaturated fatty acid. At the late stages of phylogenesis, under becoming of biological function of locomotion (motion at the expense of contraction of cross-striated skeletal myocytes) insulin began to activate absorption of glucose by cells with subsequent synthesis of endogenous ῲ-9 oleic mono-saturated fatty acid out of it. The aphysiological effect of environment factors in the form of derangement of biological function of trophology (feeding), surplus of palmitic unesterified fatty acids in food serve as a main cause of such a high rate of functional derangement - insulin resistance syndrome in populations. Hence, there is no reason to call it diabetes mellitus type II.

The role of unesterified fatty acids in diagnostic of fat embolism.

The prospective study of concentration of unesterified fatty acids in patients with severe combined trauma was carried out. In patients with fatty embolism syndrome increasing of concentration of unesterified fatty acids in arterial and venous blood in comparison with reference interval was detected. The increasing of concentration of fatty acids in arterial blood in comparison with venous blood was established. The higher diagnostic significance of arterial venous difference in concentration of unesterified fatty acids in diagnostic of fatty embolism syndrome is established.

Role of Calcium-Independent Phospholipase A2 VIA in Mediating Neurological Disorder and Cancer

Calcium-independent phospholipase A2 (iPLA2) belongs to the group VI family of phospholipase superfamily (PLA2) that catalyses the hydrolysis of glycerophospholipids at the sn-2 ester bond, producing unesterified fatty acids and 2-lysophospholipids. Research interests on iPLA2 have not been as significant as those on secretary PLA2 and cytosolic PLA2. However, more efforts have been made recently on understanding the expression, regulation and biological function of iPLA2. iPLA2 plays important roles in several biological processes, including signal transduction, phospholipid remodelling, eicosanoid formation, cell proliferation, cell differentiation and apoptosis. Modulation of iPLA2 activity can have prominent effects on cellular metabolism, central nervous system and cardiovascular functions. Thus, dysregulation iPLA2 can play a vital role in the pathogenesis of several diseases. The aim of this review is to provide the current understanding of the structure, function and regulation of group VI iPLA2 and highlight its potential mechanisms of action in mediating several neurological disorders and cancer.

The positional specificity of individual triglycerides-substrates for lipase action. The oleic triglycerides of palm oil, palmitic triglycerides of milk, ions of calcium and magnesium.

The counter-insulin effect of surplus of palmitic fatty acid in food is implemented under: a) formation in vivo of palmitic type of fatty acids metabolism with deficiency of substrate for ATP synthesis and permanent shortage of energy for accomplishment of biologic functions; b) compensatory activation of biologic function of adaptation, biologic reaction of compensation. The activation with catecholamines in visceral fatty cells of gland the hormone-dependent lipase which is not blocking insulin, increases content of unesterified fatty acids in blood plasma. Until in blood plasma the level of unesterified fatty acids is increased the cells phylogenetically justified stop absorption of glucose along with development of hyperglycemia and hypertriglyceridemia - insulin resistance syndrome. Thew increasing of content of triglycerides (alcohol glycerin) always increases cholesterol - low density lipoproteins; the highest numbers of cholesterol result in no increasing of triglycerides concentration in blood. All triglycerides of milk positionally are palmitic ones and all triglycerides of palm oil are oleic ones. The surplus of palmitic unesterified fatty acids in small intestine under hydrolysis of oleic triglycerides decreases bio-availability and absorption of ions of Ca++ and Mg++ by enterocytes. This occurrence is absent in case of hydrolysis of palmitic triglycerides of maternal milk in intestine since all released unesterified fatty acids are oleic ones. The position of fatty acids in the composition of triglyc erides is a functional characteristic of substrate under impact of positionally specific lipases in all biologic mediums.

DHA結合ホスファチジルコリン輸送に関する分子生物学的一考察

DHA levels are not homogeneously distributed throughout an animal. There are two distinct categories, select tissues containing large amounts of DHA and the remaining tissues with normally less than a few mol%. High-DHA tissues, the rod outer segment, sperm, and brain have a large quantity of DHA. DHA is mainly found on in the sn-2 position of phospholipids. DHA is n-3 fatty acid that is essential for normal brain development and cognitive function. It was confirmed a member of the major facilitator superfamily: Mfsd2a as the major transporter for DHA uptake into brain. Mfsd2a is found to be expressed exclusively in endothelium of the blood-brain barrier of micro-vessels. Mfsd2a-KO mice show markedly reduced levels of DHA in brain accompanied by neuronal cell loss in hippocampus and cerebellum. Mfsd2a transports DHA in the form of sn-2 lysophosphatidylcholine, but not unesterified fatty acid, in a sodium ion-system. A remarkable property of MFSD2 is its high-level expression specifically in the placenta, with expression in all other tissues at least 10-fold low―with the expression of the testis in which it is only 4-fold lower than the placenta. DHA is specifically bound to fatty acid binding proteins (Fabp7) in the cytoplasm, and transported to the cell membrane and work as ligands for nuclear receptor transcription factor.

Fish oil diet in pregnancy and lactation reduces pup weight and modifies newborn hepatic metabolic adaptations in rats.

To determine the effects of a diet containing fish oil (FD) during pregnancy and lactation in rats on the metabolic adaptations made by the offspring during early extrauterine life and to compare it to an olive oil diet (OD). Rats were mated and randomly allocated to OD or FD containing 10% of the corresponding oil. During lactation, litters were adjusted to eight pups per dam. Fetuses of 20days and pups of 0, 1, 10, 20 and 30days of age were studied. Body weight and length were lower in pups of the FD group from birth. The diet, milk, pups' plasma and liver of FD group had higher proportions of n-3 LCPUFA, but the content of arachidonic acid (ARA) was lower. Plasma glucose was higher, but unesterified fatty acids, triacylglycerols (TAG), 3-hydroxybutyrate and liver TAG in 1-day-old pups were lower in the FD group, and differences in some of these variables were also found in pups up to 30days old. Liver lipoprotein lipase activity and mRNA expression, and the expression of carnitine palmitoyl transferase I, acyl-CoA oxidase and 3-hydroxy 3-methyl glutaryl-CoA synthase increased more at birth in pups of the FD group, but the expression of sterol regulatory element binding protein-1c and Δ6-desaturase mRNA was lower in the FD group. Maternal intake of high n-3 LCPUFA retards postnatal development, which could be the result of impaired ARA synthesis, and affects hepatic metabolic adaptations to extrauterine life.

Milk vs Soybean Polar Lipids as Emulsifier: Faster Postprandial Lipid Metabolism through Greater Emulsion Lipolysis

ObjectiveBecause metabolic diseases are characterized by an altered lipid metabolism including prolonged postprandial hyperlipemia, we investigated the impact of using milk polar lipids as emulsifier on lipid digestion and postprandial lipemia.Methods:Mice were gavaged with emulsions stabilized with polar lipids from milk (MPL) vs soybean (SPL). Plasma and small intestine were collected during digestion. Both emulsions were also lipolyzed in vitro using a static human digestion model.Results:In vivo, MPL induced higher plasma concentrations of triglycerides (TG) and unesterified fatty acids (NEFA) than SPL at 1h after feeding. The opposite was observed after 4 h with lower TG in MPL group (PPLxtime<0.01). This was associated with a lower gene expression of ApoB and Sar1B, which are proteins involved in chylomicron structure and secretion, in the duodenum of MPL vs SPL mice (P<0.05). Chylomicrons were larger in MPL group at 4 h (P<0.01). The kinetics of synthesis and/or clearance of chylomicrons thus depended on the type of emulsifier. In vitro, TG hydrolysis from MPL emulsion was faster during intestinal phase than using SPL. This enhanced lipolysis can partly explain the sharper rise of plasma TG at 1 h in MPL group and its subsequent faster decrease.ConclusionsMilk polar lipids used as emulsifier can modulate both digestive lipolysis and postprandial lipid metabolism compared to soybean lecithin. Possible long‐term effects in humans will thus deserve further investigations.

Fatty acid binding to CD36 affects oxLDL uptake

We investigated the hypothesis that interactions of unesterified fatty acid (FA) with the plasma membrane protein CD36 affect uptake of oxLDL. Because the binding of natural FA to CD36 have not been systematically studied, we first characterized FA binding to CD36 by the biophysical method surface plasmon resonance (SPR). After covalently linking the extracellular domain of CD36 to an SPR chip surface, aqueous FA (solubilized in cyclodextrin) was pulsed across the surface, generating association and dissociation binding curves. We studied structurally different long chain FA: a saturated (palmitic acid); unsaturated (oleic acid); trans‐oleic acid; (elaidic); a polyunsaturated [docosahexaenoic acid (DHA)], and an oxidized FA [9S‐hydroxy‐10E,12Z‐octadecadienoic acid (HODE)]. With the exception of HODE, SPR detected FA binding to CD36, and showed that multiple sites are present with rapid association and dissociation kinetics that were similar to HSA. To study the role in oxLDL uptake of these FA, we used a fluorescent oxLDL (Dii‐oxLDL) live‐cell assay with confocal microscopy imaging. CD36‐mediated uptake in serum‐free media was very low but greatly increased with serum. Addition of FA in serum‐free media increased oxLDL binding and uptake to levels found with serum, and affected CD36 plasma membrane (PM) distribution. Binding/uptake of oxLDL exhibited dose dependency of added FA, with the exception of DHA, which binds avidly to CD36 but did not activate uptake. HODE, which binds poorly to CD36, did not affect oxLDL uptake. The high affinity FA binding to CD36 has important implications that binding at some or all sites could affect its conformation, binding of other ligands, and functional properties.

CD36 Binds Oxidized Low Density Lipoprotein (LDL) in a Mechanism Dependent upon Fatty Acid Binding

The association of unesterified fatty acid (FA) with the scavenger receptor CD36 has been actively researched, with focuses on FA and oxidized low density lipoprotein (oxLDL) uptake. CD36 has been shown to bind FA, but this interaction has been poorly characterized to date. To gain new insights into the physiological relevance of binding of FA to CD36, we characterized FA binding to the ectodomain of CD36 by the biophysical method surface plasmon resonance. Five structurally distinct FAs (saturated, monounsaturated (cis and trans), polyunsaturated, and oxidized) were pulsed across surface plasmon resonance channels, generating association and dissociation binding curves. Except for the oxidized FA HODE, all FAs bound to CD36, with rapid association and dissociation kinetics similar to HSA. Next, to elucidate the role that each FA might play in CD36-mediated oxLDL uptake, we used a fluorescent oxLDL (Dii-oxLDL) live cell assay with confocal microscopy imaging. CD36-mediated uptake in serum-free medium was very low but greatly increased when serum was present. The addition of exogenous FA in serum-free medium increased oxLDL binding and uptake to levels found with serum and affected CD36 plasma membrane distribution. Binding/uptake of oxLDL was dependent upon the FA dose, except for docosahexaenoic acid, which exhibited binding to CD36 but did not activate the uptake of oxLDL. HODE also did not affect oxLDL uptake. High affinity FA binding to CD36 and the effects of each FA on oxLDL uptake have important implications for protein conformation, binding of other ligands, functional properties of CD36, and high plasma FA levels in obesity and type 2 diabetes.

Adiponeсtin as humoral mediator of feedback in adipocytes of subcutaneous fatty tissue. Phylogenetic theory of general pathology; functional difference of leptin and adiponeсtin.

In spite of difference both in concentration of mono- and oligomers and in humoral regulation of visceral fatty cells and subcutaneous adipocytes, leptin and adiponeсtin are phylogenetically two different humoral mediators of biological function of trophology in paracrin regulated cenosises and at the level of organism. They separately regulate in visceral fatty cells and adipocytes realization by fatty cells such biological reactions as exotrophy, deposit of fatty acids and triglycerides and endotrophy (releasing of fatty acids in form of unesterified fatty acids). They are related both physiologically and under development of pathology. The surplus induction by physiological substrate (food), besides its amount, is aphysiological effect of environment - syndrome of overeating. The accumulation of surplus saturated and monoenic fatty acids in triglycerides in visceral fatty cells continues till: a) size of cells under their constant amount will exceed physiological size; b) there is no endoplasmic stress; c) loss of visceral fatty cells by type of apoptosis; d) development of biological reaction of inflammation in visceral fatty cells (autocrine) and paracrin cenosises; e) compensating increase of synthesis by visceral fatty cells' mediator of feedback of leptin under development of metabolic syndrome. The deposit of fatty acids in form of triglycerides is proceeded by adipocytes in case that surplus induction by substrate continues. The algorithm of compensating effect of adiponeсtin on autocrine level and cenosises of cells is the same as for leptin in visceral fatty cells. Hence, formation of alimentary obesity and compensative activation of synthesis by adipocytes of adiponeсtin with regulation of feedback. How the effect of leptin and adiponeсtin at the level of organism under expressed difference of their structure is still to be exposed.