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Fatty Acids Used (fatty + acid_used)
Selected AbstractsMacrophages transfer [14C]-labelled fatty acids to pancreatic islets in cultureCELL BIOCHEMISTRY AND FUNCTION, Issue 1 2001J. R. Garcia Jr. Abstract Macrophages are able to produce, export, and transfer fatty acids to lymphocytes in culture. The purpose of this study was to examine if labelled fatty acids could be transferred from macrophages to pancreatic islets in co-culture. We found that after 3,h of co-culture the transfer of fatty acids to pancreatic islets was: arachidonic , oleic > linoleic,=,palmitic. Substantial amounts of the transferred fatty acids were found in the phospholipid fraction; 87.6% for arachidonic, 59.9% for oleic, 53.1% for palmitic, and 36.9% for linoleic acids. The remaining radioactivity was distributed among the other lipid fractions analysed (namely polar lipids, cholesterol, fatty acids, triacylglycerol and cholesterol ester), varying with the fatty acid used. For linoleic acid, a significant proportion (63.1%) was almost equally distributed in these lipid fractions. Also, it was observed that transfer of fatty acids from macrophages to pancreatic islets is time-dependent up to 24,h, being constant and linear with time for palmitic acid and remaining constant after 12,h for oleic acid. These results lead us to postulate that in addition to the serum, circulating monocytes may also be a source of fatty acids to pancreatic islets, mainly arachidonic acid. Copyright © 2001 John Wiley & Sons, Ltd. [source] Fatty acid incorporation in endothelial cells and effects on endothelial nitric oxide synthaseEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 9 2007S. Couloubaly Abstract Background The nature of fatty acids provided by the diet as well as plasma lipid metabolism can modify the composition and properties of plasma membrane and thus the activity of membrane proteins. In humans, as well as in experimental models, diabetes is associated with both an alteration in serum lipid profile and a documented endothelial dysfunction. This in vitro study investigated on an immortalized human endothelial cell line (EA.hy 926) the specific effects of several free fatty acids (FFAs) on the composition of cellular membranes and the regulation of endothelial nitric oxide synthase (eNOS). Materials and methods 0·1% of lipid deprived serum was added to the incubation medium with 25 mm glucose in order to study the effects of individual fatty acids: myristic acid, palmitic acid, stearic acid, oleic acid or linoleic acid at 100 µm bound with albumin. The effects of the FFAs on the endothelial nitric oxide synthase were investigated on mRNA level by quantitative PCR, on protein level and Ser1177 phosphorylation by Western blot and on enzymatic activity on living cells using radiolabelled arginine. Results Free linoleic acid increased the membrane content in n-6 fatty acids (mainly C18: n-6 and its metabolites) with a decrease in saturated and monounsaturated fatty acids. These conditions decreased the basal eNOS activity and reduced the phosphorylation of eNOS-Ser1177 due to activation by histamine. Free palmitic acid enriched the membranes with 16 : 0 with a slight decrease in monounsaturated fatty acids. These conditions increased eNOS activation without increasing Ser1177 phosphorylation upon histamine activation. The addition of the other FFAs also resulted in modifications of membrane composition, which did not to affect eNOS-Ser1177 phosphorylation. Conclusion Among the fatty acids used, only modification of the membrane composition due to linoleic acid supply disturbed the basal enzymatic activity and Ser1177 phosphorylation of eNOS in a way that limited the role of histamine activation. Linoleic acid might involve the dysfunction of both eNOS basal activity and its phosphorylation status and may then contribute to an impaired vasodilatation in vivo. [source] A laser imaging and neutron reflection investigation into the monolayer behaviour of fatty acids used for taste masking microspheresJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 5 2008Sheng Qi Abstract Fatty acid microspheres have been used for taste masking purposes whereby the drug is preferentially released in the lower gastrointestinal tract, although the mechanisms involved are poorly understood. In this study, we use a combination of surface pressure measurements, Brewster angle microscopy (BAM) and neutron reflectivity measurements to study the phase miscibility and escaping tendency from mixed stearic and palmitic acid films with a view to relating this to drug dissolution behaviour. It was noted that mixed systems showed considerably greater film interaction and instability than those composed of the pure lipid, especially in alkaline media. BAM studies were able to identify a range of phase separated structures for both the pure and mixed systems. Neutron reflectivity studies indicated a marked selective dissolution of palmitic acid into the subphase as a function of time and allowed quantification of the rate of dissolution of this species. It is concluded that the fatty acids are interacting within the monolayer and in addition the palmitic acid is escaping the mixed monolayers and dissolving into the alkali subphase. These findings have strong relevance for understanding the mechanism of drug release from the associated microspheres. © 2007 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 97: 1864,1877, 2008 [source] Effect of intracellular lipid droplets on cytosolic Ca2+ and cell death during ischaemia,reperfusion injury in cardiomyocytesTHE JOURNAL OF PHYSIOLOGY, Issue 6 2009Ignasi Barba Lipid droplets (LD) consist of accumulations of triacylglycerols and have been proposed to be markers of ischaemic but viable tissue. Previous studies have described the presence of LD in myocardium surviving an acute coronary occlusion. We investigated whether LD may be protective against cell death secondary to ischaemia,reperfusion injury. The addition of oleate,bovine serum albumin complex to freshly isolated adult rat cardiomyocytes or to HL-1 cells resulted in the accumulation of intracellular LD detectable by fluorescence microscopy, flow cytometry and 1H-nuclear magnetic resonance spectroscopy. Simulated ischaemia,reperfusion of HL-1 cells (respiratory inhibition at pH 6.4 followed by 30 min of reperfusion) resulted in significant cell death (29.7 ± 2.6% of total lactate dehydrogenase release). However, cell death was significantly attenuated in cells containing LD (40% reduction in LDH release compared with control cells, P= 0.02). The magnitude of LD accumulation was inversely correlated (r2= 0.68, P= 0.0003) with cell death. The protection associated with intracellular LD was not a direct effect of the fatty acids used to induce their formation, because oleate added 30 min before ischaemia, during ischaemia or during reperfusion did not form LD and did not protect against cell death. Increasing the concentration of free oleate during reperfusion progressively decreased the protection afforded by LD. HL-1 cells labelled with fluo-4, a Ca2+ -sensitive fluorochrome, fluorescence within LD areas increased more throughout simulated ischaemia and reperfusion than in the cytosolic LD-free areas of the same cells. As a consequence, cells with LD showed less cytosolic Ca2+ overload than control cells. These results suggest that LD exert a protective effect during ischaemia,reperfusion by sequestering free fatty acids and Ca2+. [source] | ||||||||||