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Lipid Uptake (lipid + uptake)
Selected AbstractsModeling Lipid Uptake in Expanded Polytetrafluoroethylene Vascular Prostheses and Its Effects on Mechanical PropertiesARTIFICIAL ORGANS, Issue 5 2000Diego Mantovani Abstract: The radial transport across the wall of expanded polytetrafluoroethylene (ePTFE) arterial prostheses has a significant effect on lipid uptake observed in prostheses implanted in humans, which has been postulated to be one of the causes associated with implant failure. The goal of this study was to stimulate radial transport on a lipidic dispersion across the wall of an ePTFE prosthesis and investigate its effects on the circumferential mechanical properties of the prosthesis. An in vitro model was developed to simulate the lipidic radial transport across the wall. Lipids contained in a phosphatidylcholine dispersion were used as the transported molecules. Lipid concentration profiles were obtained after exposing commercial ePTFE prostheses to various transmural pressure and/or lipidic concentration gradients. Phospholipids gradually accumulated up to the external reinforcing wrap of the prosthesis, which clearly acted as a rigid barrier against lipid infiltration. Tensile tests performed on the virgin samples showed that the wrap was much more rigid than the microporous part of the prosthesis. After the lipid simulation, the rigidity of the wrap decreased with respect to what was observed for the virgin prosthesis. Finally, some clinical implications of this phenomena are discussed. [source] Molecular characterization of the role of orphan receptor small heterodimer partner in development of fatty liver,HEPATOLOGY, Issue 1 2007Jiansheng Huang The orphan receptor Small Heterodimer Partner (SHP, NROB2) regulates metabolic pathways, including hepatic bile acid, lipid, and glucose homeostasis. We reported that SHP- deletion in leptin-deficient OB,/, mice increases insulin sensitivity, and prevents the development of fatty liver. The prevention of steatosis in OB,/,/SHP,/, double mutants is not due to decreased body weight but is associated with increased hepatic very-low-density lipoprotein (VLDL) secretion and elevated microsomal triglyceride transfer protein (MTP) mRNA and protein levels. SHP represses the transactivation of the MTP promoter and the induction of MTP mRNA by LRH-1 in hepatocytes. Adenoviral overexpression of SHP inhibits MTP activity as well as VLDL-apoB protein secretion, and RNAi knockdown of SHP exhibits opposite effects. The expression of SHP in induced in fatty livers of OB,/, mice and other genetic or dietary models of steatosis, and acute overexpression of SHP by adenovirus, result in rapid accumulation of neutral lipids in hepatocytes. In addition, the pathways for hepatic lipid uptake and lipogenic program are also downregulated in OB,/,/SHP,/, mice, which may contribute to the decreased hepatic lipid content. Conclusion: These studies demonstrate that SHP regulates the development of fatty liver by modulating hepatic lipid export, uptake, and synthesis, and that the improved peripheral insulin sensitivity in OB,/,/SHP,/, mice is associated with decreased hepatic steatosis. (HEPATOLOGY 2007.) [source] Fat Uptake in French Fries as Affected by Different Potato Varieties and ProcessingJOURNAL OF FOOD SCIENCE, Issue 6 2001C.J. O'Connor ABSTRACT: The uptake of lipid into French fries was investigated using two varieties of potato (,Russet Burbank' and ,Agria') and the New Zealand sweet potato, Ipomoea batatas, (kumara). The variety of potato used had a significant effect on lipid uptake, with ,Agria' having the lowest lipid content. The different cellular structures may have affected the fat uptake in the French fries by influencing either the loss of moisture during finish-frying or the damage done to the original anatomy during processing before pre-frying. The French fries that had undergone frozen storage had a higher amount of lipid contained in their inner core than did those that had been either chilled or prepared freshly for frying. [source] Scavenger receptor class B, type I is expressed in porcine brain capillary endothelial cells and contributes to selective uptake of HDL-associated vitamin EJOURNAL OF NEUROCHEMISTRY, Issue 2 2001Daniel Goti It is clearly established that an efficient supply to the brain of ,-tocopherol (,TocH), the most biologically active member of the vitamin E family, is of the utmost importance for proper neurological functioning. Although the mechanism of uptake of ,TocH into cells constituting the blood,brain barrier (BBB) is obscure, we previously demonstrated that high-density lipoprotein (HDL) plays a major role in the supply of ,TocH to porcine brain capillary endothelial cells (pBCECs). Here we studied whether a porcine analogue of human and rodent scavenger receptor class B, type I mediates selective (without concomitant lipoprotein particle internalization) uptake of HDL-associated ,TocH in a similar manner to that described for HDL-associated cholesteryl esters (CEs). In agreement with this hypothesis we observed that a major proportion of ,TocH uptake by pBCECs occurred by selective uptake, exceeding HDL3 holoparticle uptake by up to 13-fold. The observation that selective uptake of HDL-associated CE exceeded HDL3 holoparticle up to fourfold suggested that a porcine analogue of SR-BI (pSR-BI) may be involved in lipid uptake at the BBB. In line with the observation of selective lipid uptake, RT-PCR and northern and western blot analyses revealed the presence of pSR-BI in cells constituting the BBB. Adenovirus-mediated overexpression of the human analogue of SR-BI (hSR-BI) in pBCECs resulted in a fourfold increase in selective HDL-associated ,TocH uptake. In accordance with the proposed function of SR-BI, selective HDL,CE uptake was increased sixfold in Chinese hamster ovary cells stably transfected with murine SR-BI (mSR-BI). Most importantly stable mSR-BI overexpression mediated a twofold increase in HDL-associated [14C],TocH selective uptake in comparison with control cells. In line with tracer experiments, mass transfer studies with unlabelled lipoproteins revealed that mSR-BI overexpression resulted in a twofold increase in endogenous HDL3 -associated ,TocH uptake. The results of this study indicate that SR-BI promotes the uptake of HDL-associated ,TocH into cells constituting the BBB and plays an important role during the supply of the CNS with this indispensable micronutrient. [source] Scavenger receptor A is expressed by macrophages in response to Porphyromonas gingivalis, and participates in TNF-, expressionMOLECULAR ORAL MICROBIOLOGY, Issue 6 2009M. T. Baer Introduction:,Porphyromonas gingivalis is a periodontopathic bacterium closely associated with generalized aggressive periodontal disease. Pattern recognition receptors (PRRs) participate in host response to this organism. It is likely that PRRs not previously recognized as part of the host response to P. gingivalis also participate in host response to this organism. Methods and Results:, Employing qRT-PCR, we observed increased msr1 gene expression at 2, 6, and 24 h of culture with P. gingivalis strain 381. Flow cytometry revealed increased surface expression of SR-A protein by the 24 h time point. Macrophages cultured with an attachment impaired P. gingivalis fimA - mutant (DPG3) expressed intermediate levels of SR-A expression. Heat-killed P. gingivalis stimulated SR-A expression similar to live bacteria, and purified P. gingivalis capsular polysaccharide stimulated macrophage SR-A expression, indicating that live whole organisms are not necessary for SR-A protein expression in macrophage response. As SR-A is known to play a role in lipid uptake by macrophages, we tested the ability of low-density lipoprotein (LDL) to influence the SR-A response of macrophages to P. gingivalis, and observed no effect of LDL on P. gingivalis -elicited SR-A expression. Lastly, we observed that SR-A knockout (SR-A,/,) mouse macrophages produced significantly more tumor necrosis factor (TNF)-, than wild type mouse macrophages cultured with P. gingivalis. Conclusion:, These data identify that SR-A is expressed by macrophages in response to P. gingivalis, and support that this molecule plays a role in TNF-, production by macrophages to this organism. [source] Modeling Lipid Uptake in Expanded Polytetrafluoroethylene Vascular Prostheses and Its Effects on Mechanical PropertiesARTIFICIAL ORGANS, Issue 5 2000Diego Mantovani Abstract: The radial transport across the wall of expanded polytetrafluoroethylene (ePTFE) arterial prostheses has a significant effect on lipid uptake observed in prostheses implanted in humans, which has been postulated to be one of the causes associated with implant failure. The goal of this study was to stimulate radial transport on a lipidic dispersion across the wall of an ePTFE prosthesis and investigate its effects on the circumferential mechanical properties of the prosthesis. An in vitro model was developed to simulate the lipidic radial transport across the wall. Lipids contained in a phosphatidylcholine dispersion were used as the transported molecules. Lipid concentration profiles were obtained after exposing commercial ePTFE prostheses to various transmural pressure and/or lipidic concentration gradients. Phospholipids gradually accumulated up to the external reinforcing wrap of the prosthesis, which clearly acted as a rigid barrier against lipid infiltration. Tensile tests performed on the virgin samples showed that the wrap was much more rigid than the microporous part of the prosthesis. After the lipid simulation, the rigidity of the wrap decreased with respect to what was observed for the virgin prosthesis. Finally, some clinical implications of this phenomena are discussed. [source] | ||||||||||