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Fraser DR. Vitamin D toxicity related to its physiological and unphysiological supply. Trends Endocrinol Metab 2021; 32:929-940. [PMID: 34518055 DOI: 10.1016/j.tem.2021.08.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2021] [Revised: 08/16/2021] [Accepted: 08/21/2021] [Indexed: 11/13/2022]
Abstract
Vitamin D is defined as a nutrient despite its rare occurrence in food. Vitamin D status is determined mainly by solar UV light action in skin. However, the strategy to combat vitamin D deficiency has been to increase oral intake of vitamin D in greater amounts than could be obtained from food. Persistent large intakes of vitamin D can cause hypercalcaemic toxicity. Although the amounts recommended to prevent deficiency are far less than those causing such toxicity, the possibility of other toxic actions from increased intake of vitamin D has been ignored. Animal experiments have demonstrated that moderate amounts of oral vitamin D over time result in atherosclerosis. Differences in the fate of vitamin D could explain this angiotoxicity.
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Affiliation(s)
- David R Fraser
- Sydney School of Veterinary Science, The University of Sydney, Sydney, NSW 2006, Australia.
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2
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Brown AJ, Sharpe LJ, Rogers MJ. Oxysterols: From physiological tuners to pharmacological opportunities. Br J Pharmacol 2020; 178:3089-3103. [PMID: 32335907 DOI: 10.1111/bph.15073] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 04/11/2020] [Accepted: 04/14/2020] [Indexed: 02/06/2023] Open
Abstract
Oxysterols are oxygenated forms of cholesterol generated via autooxidation by free radicals and ROS, or formed enzymically by a variety of enzymes such as those involved in the synthesis of bile acids. Although found at very low concentrations in vivo, these metabolites play key roles in health and disease, particularly in development and regulating immune cell responses, by binding to effector proteins such as LXRα, RORγ and Insig and directly or indirectly regulating transcriptional programmes that affect cell metabolism and function. In this review, we summarise the routes by which oxysterols can be generated and subsequently modified to other oxysterol metabolites and highlight their diverse and profound biological functions and opportunities to alter their levels using pharmacological approaches. LINKED ARTICLES: This article is part of a themed issue on Oxysterols, Lifelong Health and Therapeutics. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v178.16/issuetoc.
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Affiliation(s)
- Andrew J Brown
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, New South Wales, Australia
| | - Laura J Sharpe
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, New South Wales, Australia
| | - Michael J Rogers
- Garvan Institute of Medical Research and St Vincent's Clinical School, UNSW Sydney, Sydney, New South Wales, Australia
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Mori TA, Croft KD, Puddey IB, Beilin LJ. Analysis of native and oxidized low-density lipoprotein oxysterols using gas chromatography—mass spectrometry with selective ion monitoring. Redox Rep 2016; 2:25-34. [DOI: 10.1080/13510002.1996.11747023] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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4
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Hamdy OM, Alizadeh A, Julian RR. The innate capacity of proteins to protect against reactive radical species. Analyst 2016; 140:5023-8. [PMID: 26051477 DOI: 10.1039/c5an00798d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Maintaining redox homeostasis, or the balance of oxidant and antioxidant forces, is essential for proper cellular functioning in biology. Although the antioxidant nature of many small molecules such as vitamin c and glutathione have been thoroughly investigated, contributions to redox homeostasis from larger biomolecules have received less attention. Evidence has shown that some proteins are antioxidant (in a non-catalytic sense), but large scale examination of this property for a diverse set of proteins has proven difficult. Herein, radical-directed dissociation mass spectrometry (RDD-MS) is used to examine the antioxidant capacity of a series of proteins with diverse biological roles, persistence intervals, and localizations. Digestion of these proteins reveals that all contain antioxidant peptide regions. Examination of the amino acid content of the antioxidant peptides does not reveal significant differences relative to normal peptides, suggesting that sequence may be more important than residue content. Sequence homology analysis across organisms reveals that antioxidant regions are frequently conserved, although many of these regions are also known to have other functions which may have influenced evolutionary pressure. Regardless of the origin, it is clear that many proteins may play secondary roles as sacrificial antioxidants within the cellular milieu.
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Affiliation(s)
- Omar M Hamdy
- Department of Chemistry, University of California, Riverside, California 92521, USA.
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5
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Pallebage-Gamarallage M, Takechi R, Lam V, Elahy M, Mamo J. Pharmacological modulation of dietary lipid-induced cerebral capillary dysfunction: Considerations for reducing risk for Alzheimer's disease. Crit Rev Clin Lab Sci 2015; 53:166-83. [PMID: 26678521 DOI: 10.3109/10408363.2015.1115820] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
An increasing body of evidence suggests that cerebrovascular dysfunction and microvessel disease precede the evolution of hallmark pathological features that characterise Alzheimer's disease (AD), consistent with a causal association for onset or progression. Recent studies, principally in genetically unmanipulated animal models, suggest that chronic ingestion of diets enriched in saturated fats and cholesterol may compromise blood-brain barrier (BBB) integrity resulting in inappropriate blood-to-brain extravasation of plasma proteins, including lipid macromolecules that may be enriched in amyloid-β (Aβ). Brain parenchymal retention of blood proteins and lipoprotein bound Aβ is associated with heightened neurovascular inflammation, altered redox homeostasis and nitric oxide (NO) metabolism. Therefore, it is a reasonable proposition that lipid-lowering agents may positively modulate BBB integrity and by extension attenuate risk or progression of AD. In addition to their robust lipid lowering properties, reported beneficial effects of lipid-lowering agents were attributed to their pleiotropic properties via modulation of inflammation, oxidative stress, NO and Aβ metabolism. The review is a contemporary consideration of a complex body of literature intended to synthesise focussed consideration of mechanisms central to regulation of BBB function and integrity. Emphasis is given to dietary fat driven significant epidemiological evidence consistent with heightened risk amongst populations consuming greater amounts of saturated fats and cholesterol. In addition, potential neurovascular benefits associated with the use of hypolipidemic statins, probucol and fenofibrate are also presented in the context of lipid-lowering and pleiotropic properties.
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Affiliation(s)
- Menuka Pallebage-Gamarallage
- a Faculty of Health Sciences , School of Public Health Curtin University , Perth , WA , Australia and.,b Curtin Health Innovation Research Institute of Aging and Chronic Disease, Curtin University , Perth , WA , Australia
| | - Ryusuke Takechi
- a Faculty of Health Sciences , School of Public Health Curtin University , Perth , WA , Australia and.,b Curtin Health Innovation Research Institute of Aging and Chronic Disease, Curtin University , Perth , WA , Australia
| | - Virginie Lam
- a Faculty of Health Sciences , School of Public Health Curtin University , Perth , WA , Australia and.,b Curtin Health Innovation Research Institute of Aging and Chronic Disease, Curtin University , Perth , WA , Australia
| | - Mina Elahy
- a Faculty of Health Sciences , School of Public Health Curtin University , Perth , WA , Australia and.,b Curtin Health Innovation Research Institute of Aging and Chronic Disease, Curtin University , Perth , WA , Australia
| | - John Mamo
- a Faculty of Health Sciences , School of Public Health Curtin University , Perth , WA , Australia and.,b Curtin Health Innovation Research Institute of Aging and Chronic Disease, Curtin University , Perth , WA , Australia
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Andrés S, Huerga L, Mateo J, Tejido M, Bodas R, Morán L, Prieto N, Rotolo L, Giráldez F. The effect of quercetin dietary supplementation on meat oxidation processes and texture of fattening lambs. Meat Sci 2014; 96:806-11. [DOI: 10.1016/j.meatsci.2013.09.020] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2013] [Revised: 07/03/2013] [Accepted: 09/09/2013] [Indexed: 10/26/2022]
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8
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The liver antioxidant status of fattening lambs is improved by naringin dietary supplementation at 0.15% rates but not meat quality. Animal 2012; 6:863-70. [PMID: 22558934 DOI: 10.1017/s175173111100214x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Twenty Assaf lambs fed barley straw plus a concentrate alone (CONTROL group) or enriched with naringin (1.5 g/kg DM, NARINGIN group) were used to assess the effect of this polyphenolic compound on meat quality attributes. Serum samples were collected for 7 weeks, then the animals were slaughtered and the livers and longissimus thoracis et lumborum muscles extracted for analysis. Triacylglycerol levels in the serum samples tended to show (P = 0.087) lower average values for the NARINGIN group when compared with the CONTROL, but no differences were observed when the meat was analysed for the intramuscular fat content. Lower thiobarbituric acid-reactive substances procedure (TBARS) values (P < 0.001) in the liver of the NARINGIN group were detected, probably as a consequence of naringenin accumulation in this organ. No significant differences were observed in the meat samples concerning TBARS or colour evolution during refrigerated storage, as not enough naringenin would have reached the muscle. Independent of naringin administration, the low levels of the most atherogenic oxysterols must be highlighted as the most important quality score in the lamb meat samples studied.
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Morán L, Andrés S, Bodas R, Prieto N, Giráldez FJ. Meat texture and antioxidant status are improved when carnosic acid is included in the diet of fattening lambs. Meat Sci 2012; 91:430-4. [DOI: 10.1016/j.meatsci.2012.02.027] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2011] [Revised: 02/23/2012] [Accepted: 02/25/2012] [Indexed: 11/29/2022]
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Andrade L, de Almeida M, Paixão J, Carvalho J, Sá e Melo M. 3β,5α,6β-Trihy-droxy-androstan-17-one. Acta Crystallogr Sect E Struct Rep Online 2011; 67:o1056-7. [PMID: 21754383 PMCID: PMC3089281 DOI: 10.1107/s1600536811011706] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2011] [Accepted: 03/29/2011] [Indexed: 11/18/2022]
Abstract
The title compound, C(19)H(30)O(4), is an androstan-17-one derivative synthesized from the dehydro-epiandrosterone through a sequential addition of an oxidant, followed by a trans-diaxial opening of the epoxide generated, with Bi(OTf)(3) (OTf is trifluoro-methane-sulfonate). The six-membered rings have a slightly flattened chair conformation, while the five-membered ring adopts a 14-α envelope conformation. All rings are trans fused. In the crystal, the mol-ecules are connected by O-H⋯O hydrogen bonds involving the hydroxyl and carbonyl groups, forming a three-dimensional network. A quantum mechanical ab initio Roothan Hartree-Fock calculation of the free mol-ecule gives bond lengths, valency angles and ring torsion angles of the free molecule at equilibrium geometry (energy minimum) close to the experimental values.
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Affiliation(s)
- L.C.R. Andrade
- CEMDRX, Department of Physics, University of Coimbra, P-3004-516 Coimbra, Portugal
| | - M.J.B.M. de Almeida
- CEMDRX, Department of Physics, University of Coimbra, P-3004-516 Coimbra, Portugal
| | - J.A. Paixão
- CEMDRX, Department of Physics, University of Coimbra, P-3004-516 Coimbra, Portugal
| | - J.F.S. Carvalho
- Centre for Neuroscience and Cell Biology, University of Coimbra, P-3004-517 Coimbra, Portugal
| | - M.L. Sá e Melo
- Centre for Neuroscience and Cell Biology, University of Coimbra, P-3004-517 Coimbra, Portugal
- Faculty of Pharmacy, University of Coimbra, P-3000-548 Coimbra, Portugal
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11
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Muslin AJ. Phenotypic high-throughput screening in atherosclerosis research: focus on macrophages. J Cardiovasc Transl Res 2010; 3:448-53. [PMID: 20625867 DOI: 10.1007/s12265-010-9205-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2010] [Accepted: 06/21/2010] [Indexed: 10/19/2022]
Abstract
Atherosclerosis is a complex disease characterized by arterial lesions consisting of macrophage foam cells, smooth muscle cells, lymphocytes and other cell types. As atherosclerotic lesions mature, they can rupture and thereby trigger thrombosis that can result in tissue infarction. Macrophage foam cells develop in the subendothelial space when cells take up cholesterol from modified forms of low-density lipoprotein (LDL) and other apolipoprotein B-containing lipoproteins. Current therapies to limit atherosclerosis focus on altering the plasma lipid composition, most commonly by reducing circulating LDL levels. No current therapy is specifically designed to alter the cellular composition of atherosclerotic lesions. To address this deficit, phenotypic high-throughput drug screens have been developed to identify compounds that reduce the uptake of oxidized LDL by macrophages or to identify compounds that increase the efflux of cholesterol from macrophages. Additional phenotypic screens can be envisaged that address cellular processes in active atherosclerotic lesions including macrophage apoptosis and efferocytosis.
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Affiliation(s)
- Anthony J Muslin
- Center for Cardiovascular Research, Washington University School of Medicine, 660 South Euclid Avenue, Box 8086, St. Louis, MO 63110, USA.
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13
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14
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Liao PL, Cheng YW, Li CH, Lo YL, Kang JJ. Cholesterol-3-beta, 5-alpha, 6-beta-triol induced PI3K-Akt-eNOS-dependent cyclooxygenase-2 expression in endothelial cells. Toxicol Lett 2009; 190:172-8. [DOI: 10.1016/j.toxlet.2009.07.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2009] [Revised: 07/06/2009] [Accepted: 07/08/2009] [Indexed: 10/20/2022]
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15
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Zanardi E, Battaglia A, Ghidini S, Conter M, Badiani A, Ianieri A. Lipid oxidation of irradiated pork products. Lebensm Wiss Technol 2009. [DOI: 10.1016/j.lwt.2009.02.016] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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16
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Cholestane-3β,5α,6β-triol-induced reactive oxygen species production promotes mitochondrial dysfunction in isolated mice liver mitochondria. Chem Biol Interact 2009; 179:81-7. [DOI: 10.1016/j.cbi.2008.12.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2008] [Revised: 12/02/2008] [Accepted: 12/04/2008] [Indexed: 01/05/2023]
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17
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18
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van Poppel G, van de Vijver LPL, Kosmeyer Schuil T, Johanns ESD, Kardinaal AFM, van de Bovenkamp P, Kruyssen DACM, Kok FJ. Plasma oxysterols and angiographically determined coronary atherosclerosis: a case control study. Biomarkers 2008; 2:373-8. [DOI: 10.1080/135475097231472] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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19
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Naito Y, Shimozawa M, Manabe H, Nakabe N, Katada K, Kokura S, Yoshida N, Ichikawa H, Kon T, Yoshikawa T. Azelnidipine, a new calcium channel blocker, inhibits endothelial inflammatory response by reducing intracellular levels of reactive oxygen species. Eur J Pharmacol 2006; 546:11-8. [PMID: 16919261 DOI: 10.1016/j.ejphar.2006.07.030] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2006] [Revised: 06/19/2006] [Accepted: 07/11/2006] [Indexed: 10/24/2022]
Abstract
Oxidized low-density lipoprotein (ox-LDL) plays an important in the development of atherosclerosis by stimulating the production of reactive oxygen species in endothelial cells, and thereby up-regulating vascular cell adhesion molecule-1 (VCAM-1). The objectives of the present study were to determine the effects of azelnidipine, a new calcium channel blocker, on the expression of VCAM-1 induced by 7-ketocholesterol, components of ox-LDL, and tumor necrosis factor-alpha (TNF-alpha). The scavenging activities of azelnidipine against superoxide, hydroxyl, and carbon-centered radicals were determined by electron spin resonance assay. The levels of intracellular reactive oxygen species were determined fluorometrically with the use of dichlorodihydrofluorescein diacetate (H(2)DCF-DA). Human aortic endothelial cells and U937 were used as endothelial cells and monocytic cells, respectively. The surface expression and mRNA levels of VCAM-1 were determined by enzyme immunoassay and RT-PCR performed on endothelial cell monolayers stimulated with 7-ketocholesterol or TNF-alpha. The numbers of monocytic cells adhering on the stimulated endothelial cells were counted in the microscopic fields. Translocation of p65 protein to the nucleus was estimated by fluorescence microscopy. Azelnidipine, but not nifedipine, reduced the signal intensity of 1,1-diphenyl-2-picrylhydrazyl radicals. Azelnidipine scavenged hydroxyl radicals, but not superoxide radicals. Intracellular levels of reactive oxygen species and RelA (p65) nuclear translocation in stimulated endothelial cells were reduced by azelnidipine. Azelnidipine significantly inhibited the expression of protein and mRNA of VCAM-1, and prevented the U937 cell adhesion to endothelial cells treated with 7-ketocholesterol or TNF-alpha. These results suggest that azelnidipine works as an anti-atherogenic agent by inhibiting the reactive oxygen species-dependent expression of VCAM-1 induced by 7-ketocholesterol and TNF-alpha.
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Affiliation(s)
- Yuji Naito
- Department of Medical Proteomics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kyoto 602-8566, Japan.
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20
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Kummerow FA, Mahfouz MM, Zhou Q, Cook LS. 27-Hydroxycholesterol causes remodeling in endothelial cell membrane lipid composition comparable to remodeling in the failed vein grafts of CABG patients. Life Sci 2006; 78:958-63. [PMID: 16154158 DOI: 10.1016/j.lfs.2005.06.023] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2005] [Accepted: 06/01/2005] [Indexed: 11/18/2022]
Abstract
Our objective is to determine if vascular remodeling in CABG patients is related to oxysterols, therefore, we compared failed vein grafts from 18 patients, available after a second coronary artery bypass grafting (CABG), with human endothelial cells (ECs). The ECs were cultured in minimum essential medium (MEM) with or without 27-hydroxycholesterol (27OHC), one of the oxysterol products of oxidatively modified low density lipoproteins (ox-LDL), as an agent to alter molecular mechanisms in vascular cells. Significant changes in phospholipid composition, in fatty acid profile and in calcium concentration were found in the failed vein compared to the native saphenous vein from the same (CABG) patient. The failed vein contained significantly less phosphatidylethanolamine, more sphingomyelin, less arachidonic acid, more linoleic acid and more calcium than the native saphenous vein. Comparable changes in phospholipid composition, in fatty acid profile and increased calcium influx were reproduced in ECs cultured in medium containing 27OHC indicating that an oxysterol is an agent that can alter the lipid composition of vascular cell membranes. Our study indicates that a lipid agent, as well as protein agents that have previously been linked to the process of vascular remodeling, may be fundamental to many vascular diseases.
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Affiliation(s)
- Fred A Kummerow
- Burnsides Research Laboratory, University of Illinois, 1208 W. Pennsylvania Ave., Urbana IL 61801, USA.
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21
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Leonarduzzi G, Chiarpotto E, Biasi F, Poli G. 4-Hydroxynonenal and cholesterol oxidation products in atherosclerosis. Mol Nutr Food Res 2005; 49:1044-9. [PMID: 16270277 DOI: 10.1002/mnfr.200500090] [Citation(s) in RCA: 306] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
4-Hydroxynonenal (HNE) is by far the most investigated aldehydic end-product of oxidative breakdown of membrane n-6 polyunsaturated fatty acids. Its potential involvement in the pathogenesis of atherosclerosis has been corroborated by its consistent detection in both oxidized LDL and fibrotic plaque in humans. HNE has been shown to activate both macrophage and smooth muscle cells, i.e. the two key cell types in chronic inflammatory processes characterized by excessive fibrogenesis. By signalling to the nucleus, the aldehyde may up-regulate in these cells both expression and synthesis of monocyte chemotactic protein 1 (MCP-1) and transforming growth factor beta1 (TGFbeta1). Oxysterols, namely 27 carbon atoms oxidation products of cholesterol, are found in relatively high amount in LDL from hypercholesterolemic individuals and are consistently detectable in foam cells and necrotic core of human atherosclerotic lesion. As for HNE, the challenge of cells of the macrophage lineage with a mixture of oxysterols like that detectable in hypercholesterolemic individuals led to a marked overexpression of TGFbeta1 and MCP-1. Both HNE and oxysterols then appear to be candidates for a primary role in the progression of the atherosclerotic process.
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Shimozawa M, Naito Y, Manabe H, Uchiyama K, Kuroda M, Katada K, Yoshida N, Yoshikawa T. 7-Ketocholesterol enhances the expression of adhesion molecules on human aortic endothelial cells by increasing the production of reactive oxygen species. Redox Rep 2005; 9:370-5. [PMID: 15720835 DOI: 10.1179/135100004225006902] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
The aim of the present study was to assess the expression of intracellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1), monocytic adhesion of human aortic endothelial cells (HAECs), and the production of intracellular reactive oxygen species (ROS), when HAECs were stimulated by 7-ketocholesterol. 7-ketocholesterol enhances surface expression of ICAM-1 and VCAM-1 as determined by EIA, induces their mRNA expression by RT-PCR, and stimulates adhesiveness of HAECs to U937 monocytic cells. We confirmed up-regulation of ROS production of HAECs treated with 7-ketocholesterol. Although the surface expression of ICAM-1 and VCAM-1 on HAECs treated with 7-ketocholesterol increased in a time-dependent manner, alpha-tocopherol inhibited this increase of the surface expression of ICAM-1 and VCAM-1. In the monocytic adhesion assay, adhesion of U937 to HAECs treated with 7-ketocholesterol was enhanced, but monoclonal anti-ICAM-1 and VCAM-1 antibodies reduced the endothelial adhesiveness. In conclusion, this study suggests that the endothelial adhesiveness to monocytic cells that was increased by 7-ketocholesterol was associated with enhanced expression of ICAM-1 and VCAM-1 mediated by ROS production.
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Affiliation(s)
- Makoto Shimozawa
- Department of Inflammation and Immunology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
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Raith K, Brenner C, Farwanah H, Müller G, Eder K, Neubert RHH. A new LC/APCI-MS method for the determination of cholesterol oxidation products in food. J Chromatogr A 2005; 1067:207-11. [PMID: 15844526 DOI: 10.1016/j.chroma.2004.12.053] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cholesterol oxidation products (COPs) can be formed in the body or in animal foods from cholesterol during food processing. A new method for the extraction and quantification of cholesterol, 7-ketocholesterol, cholestane-3beta-5alpha-6beta-triol, 25-hydroxycholesterol, 5,6alpha-epoxycholesterol, and 7beta-hydroxycholesterol by means of reversed-phase LC/atmospheric pressure chemical ionization mass spectrometry is presented. A baseline separation of all COPs was achieved, allowing a separate quantification also for isobaric compounds. The limits of detection were 15-30 ng/mL, quantification was performed from 100 ng/mL to 10 microg/mL with RSD < 2%. The method was applied successfully to the determination of cholesterol and COPs in processed foods such as pork, beef, chicken, and egg.
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Affiliation(s)
- Klaus Raith
- Institute of Pharmaceutics and Biopharmaceutics, Martin Luther University, Wittenberg, 06120 Halle (S), Germany.
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Liu H, Yuan L, Xu S, Wang K, Zhang T. Cholestane-3β,5α,6β-triol inhibits osteoblastic differentiation and promotes apoptosis of rat bone marrow stromal cells. J Cell Biochem 2005; 96:198-208. [PMID: 16052487 DOI: 10.1002/jcb.20510] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Converging lines of evidence suggest that oxidized lipids, long recognized as a risk factor in atherogenesis, also contribute to osteoporosis, but the underlying mechanism is not understood in detail. The effect of atherogenesis related factors including oxysterols on the differentiation and survival of marrow stromal cells (MSCs) would be very important in understanding the link between atherosclerosis and osteoporosis. In the present study, the effect of oxysterol cholestane-3beta,5alpha,6beta-triol (Triol) on osteoblastic differentiation and apoptosis of primary rat bone MSCs as well as the related mechanisms were studied. Triol inhibited MSCs osteoblastic differentiation as demonstrated by inhibition of alkaline phosphatase activity, osteocalcin secretion, and matrix mineralization. In the other aspect, Triol promoted MSCs apoptosis, as characterized by condensed or fragmented nuclei as well as active externalization of phosphatidyl serine to the cell surface. In addition, Triol was found to induce increases of intracellular Ca2+ and Ca2+-dependent reactive oxygen species generation in MSCs. These effects were involved in the action of Triol on apoptosis, but not on osteoblastic differentiation of MSCs. These results suggested that Triol might contribute to the decreased bone formation by inhibition of osteoblastic differentiation and promotion of apoptosis of MSCs, providing insights about common factors underlying the pathogenesis of atherosclerosis and osteoporosis.
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Affiliation(s)
- Hongmei Liu
- Department of Chemical Biology, Peking University School of Pharmaceutical Sciences, Beijing 100083, PR China
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Liu H, Yuan L, Xu S, Zhang T, Wang K. Cholestane-3β, 5α, 6β-triol promotes vascular smooth muscle cells calcification. Life Sci 2004; 76:533-43. [PMID: 15556166 DOI: 10.1016/j.lfs.2004.06.025] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2004] [Accepted: 06/17/2004] [Indexed: 10/26/2022]
Abstract
Oxysterols found in atherosclerotic plaque may be associated with vascular calcification. We investigated the effect of oxysterol cholestane-3beta, 5alpha, 6beta-triol (Triol) on in vitro calcification of rat vascular smooth muscle cells (VSMCs). In vitro calcification was induced by incubation of VSMCs with beta-glycerophosphate. Calcifying nodule formation, calcium deposition in extracellular matrix, and alkaline phosphatase (ALP) activity were measured as indices of calcification. Because apoptotic bodies can serve as nucleation sites for calcification, apoptosis of calcifying VSMCs was determined by Hoechst 33258 staining, TUNEL, and FITC-labeled annexin V/PI double staining. The calcium deposition and ALP activity in calcifying VSMCs were much higher than those in non-calcifying VSMCs. Triol increased calcifying nodule formation, calcium deposition, ALP activity, and apoptosis of nodular cells in calcifying VSMCs. As determined by 2,7-dichlorofluorescein fluorescence, Triol induced the generation of reactive oxygen species (ROS) in calcifying VSMCs dose- and time-dependently. Triol-induced increases in calcium deposition, ALP activity, apoptosis, and ROS generation were all attenuated by antioxidant vitamin C plus vitamin E (VC + VE). The results demonstrated that Triol promoted VSMCs calcification through direct increase of ALP activity and apoptosis, probably by ROS-related mechanism.
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Affiliation(s)
- Hongmei Liu
- Department of Chemical Biology, Peking University School of Pharmaceutical Sciences, 38 Xueyuan Road, Beijing 100083, PR China
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26
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Tang R, Huang K. Inhibiting effect of selenium on oxysterols-induced apoptosis of rat vascular smooth muscle cells. J Inorg Biochem 2004; 98:1678-85. [PMID: 15522395 DOI: 10.1016/j.jinorgbio.2004.07.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2004] [Revised: 06/23/2004] [Accepted: 07/05/2004] [Indexed: 11/27/2022]
Abstract
To evaluate the cytoprotection mechanism of selenium against cholestane-3beta,5alpha,6beta-triol (3-triol)-induced vascular smooth muscle cells (VSMCs) damage, cell viability was analyzed by 3-(4,5-dimethylthiazol-2 -yl)-2,5-diphenyltetrazolium bromide (MTT) assay and cell count, the percentage release of lactate dehydrogenase (LDH) from the cell was assessed, and apoptosis was detected by DNA laddering and flow cytometric analysis. Meanwhile, the activity of glutathione peroxidase (GPx) of VSMCs was measured. The results showed that 3-triol could inhibit proliferation of VSMCs time-dependently and dose-dependently, increase the percentage release of LDH and induce VSMCs apoptosis. While the cytotoxicity and cells apoptosis induced by 3-triol was attenuated by pretreatment of cells with low concentration of sodium selenite, and the longer the pretreated time was, the stronger the inhibition was. Preincubation of cells with sodium selenite (50 nM) for 12 or 24 h before 1, 5, 10, 25, or 50 microM 3-triol exposure, the cell viabilities increased 28.5% (P<0.05), 18.3%, 197.6% (P<0.01), 66.7%, 50.0% or 35.1% (P<0.05), 62.3% (P<0.05), 329.6% (P<0.01), 221.3% (P<0.05), 74.0% compared with the control cells, respectively. When the cells were preincubated with sodium selenite (50 nM) for 12 or 24 h before exposure to 3-triol (10 microM), the percent of apoptotic cells reduced from 30.47+/-15.34% to 26.88+/-17.32% or 7.41+/-5.46% (P<0.05). With preincubation of sodium selenite (50 nM) for 24 h, the GPx activity of VSMCs increased 18.5% compared with control (P<0.05). In conclusion, the results suggested that incubated VSMCs could absorb and transfer selenite as selenoprotrein, such as GPx, if the time is long enough and VSMCs selenoproteins can protect markedly against apoptosis and damage induced by 3-triol in VSMCs.
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Affiliation(s)
- Rong Tang
- Department of Chemistry, Huazhong University of Science and Technology, 1037 Luoyu Lu, Hongshan, Wuhan, Hubei 430074, People's Republic of China
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27
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Effect of Cooking and Packaging Methods on the Thiobarbituric Acid Reactive Substances and Cholesterol Oxidation Products of Turkey Thigh Meat Patties During Storage. JOURNAL OF ANIMAL SCIENCE AND TECHNOLOGY 2004. [DOI: 10.5187/jast.2004.46.3.397] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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28
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Souidi M, Dubrac S, Parquet M, Milliat F, Férézou J, Sérougne C, Loison C, Riottot M, Boudem N, Bécue T, Lutton C. Effects of dietary 27-hydroxycholesterol on cholesterol metabolism and bile acid biosynthesis in the hamster. Can J Physiol Pharmacol 2003; 81:854-63. [PMID: 14614521 DOI: 10.1139/y03-079] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
27-hydroxycholesterol (27OH-Chol) is an important endogenous oxysterol resulting from the action of sterol 27-hydroxylase (CYP27A1) on cholesterol in the liver and numerous extrahepatic tissues. It may act as a modulator of cholesterol and bile acid metabolism. The effects of 27OH-Chol on the main enzymes and receptors of cholesterol metabolism were investigated by feeding male hamsters a diet supplemented with 27OH-Chol (0.1% w/w) for 1 week. Intestinal scavenger class B, type I (SR-BI) protein level was decreased (65%), but hepatic expression was increased (+34%). Liver 3β-hydroxy-3β-methyl glutaryl coenzyme A reductase (58%), cholesterol 7α-hydroxylase (54%), oxysterol 7α-hydroxylase (44%), and sterol 12α-hydroxylase (70%) activities were all decreased. Bile acid composition was changed (fourfold increase in the chenodeoxycholic/cholic acid ratio). This study demonstrates that dietary 27OH-Chol modulates major enzymes of cholesterol metabolism and alters the biliary bile acid profile, making it more hydrophobic, at least at this level of intake. Its effects on SR-BI protein levels are organ dependent. The properties of 27OH-Chol or its metabolites on cholesterol metabolism probably result from the activation of specific transcription factors. Key words: cholesterol 7α-hydroxylase (CYP7A1), sterol 12α-hydroxylase (CYP8B1), sterol 27-hydroxylase (CYP27A1), 3β-hydroxy-3β-methyl glutaryl coenzyme A reductase (HMGCoAR), scavenger receptor class B type I (SR-BI).
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Affiliation(s)
- Maâmar Souidi
- Laboratory of Physiology and Nutrition, Bâtiment 447, Université Paris-Sud, 91405 Orsay CEDEX, France
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29
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Leonarduzzi G, Sottero B, Poli G. Oxidized products of cholesterol: dietary and metabolic origin, and proatherosclerotic effects (review). J Nutr Biochem 2002; 13:700-710. [PMID: 12550054 DOI: 10.1016/s0955-2863(02)00222-x] [Citation(s) in RCA: 140] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Cholesterol oxidation products, termed oxysterols, are increasingly considered of potential interest in the pathogenesis of atherosclerotic lesions. Of dietary or endogenous origin, oxysterols may occur in significant amounts in low density lipoprotein (LDL) particles, especially in hypercholesterolemic subjects. They likely contribute to the uptake of modified LDL by scavenger receptors and some of them finally accumulate in the subintimal space of major arteries; here cholesterol oxides may favor the perpetuation of a chronic inflammatory state, through their ability to trigger irreversible damage of vascular cells with consequent activation of phagocytes. Furthermore, practically all oxysterols of major pathophysiologic interest have been shown to markedly up-regulate expression and synthesis of adhesion molecules, inflammatory cytokines and chemokines. Cholesterol oxidation thus appears to be an important biochemical pathway through which it exerts toxic, inflammatory and finally atherogenic effects.
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Affiliation(s)
- Gabriella Leonarduzzi
- Department of Clinical and Biological Sciences, University of Turin, S. Luigi Gonzaga Hospital, 10043 (Turin), Orbassano, Italy
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30
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Huang K, Liu H, Chen Z, Xu H. Role of selenium in cytoprotection against cholesterol oxide-induced vascular damage in rats. Atherosclerosis 2002; 162:137-44. [PMID: 11947907 DOI: 10.1016/s0021-9150(01)00707-9] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Wistar rats were fed Se-deficient (0.038 mg/kg diet) and adequate (0.326 mg/kg diet) diets for 13 weeks. The blood Se content, blood and vascular wall glutathione peroxidase (GPx) activity, serum high-density lipoprotein cholesterol (HDL-C) level and plasma prostacyclin (PGI(2)) concentration were decreased significantly, and the blood lipid peroxide (LPO) concentration, serum low-density lipoprotein cholesterol (LDL-C), total cholesterol (TC) level and plasma thromboxane A(2) (TXA(2)), content were increased significantly in Se-deficient rats compared with Se-adequate group, respectively. Furthermore the Se-deficient and adequate rats were given 5 mg/kg of cholestane-3 beta, 5 alpha, 6 beta -triol (3-triol) or vehicle only. Twenty four hours after treatment, the plasma PGI(2) level was decreased in Se-adequate rats infused 3-triol (+3 triol), meanwhile, the level in Se- deficient +3-triol group was much lower than that in Se-adequate +3-triol group. Compared with Se-adequate group, plasma TXA(2) content in Se-adequate +3-triol group had no significantly difference, but in Se- deficient rats infused 3-triol, plasma TXA(2) content was much higher than that in Se-adequate +3-triol group. The plasma ET concentration in Se-deficient group decreased slightly, but the concentration in Se-adequate +3-triol group increased significantly with respect to Se-deficient group. Although plasma ET concentration in Se-deficient group +3-triol did not increase, it was significantly lower than that in Se-adequate +3-triol group. The luminal surfaces of aorta thoracica of experimental rats were examined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Observed by SEM, the luminal surface of aorta of Se-deficient rats showed few crater-like defects due to the disruption of endothelial cell. Se-adequate +3-triol group showed some crater-like defects on the their aorta luminal surface, but the luminal surface of Se-deficient +3-triol group exhibited numerous crater-like defects and appeared sponge-like as well as platelets adhering followed by thrombus formation in focal area of extensive endothelial damage. TEM studies also showed that the endothelium of aorta of Se deficient +3-triol group had more frequent lesion where endothelial cell plasma were swelling with profuse intracellular edema and some vacuoles were seen in cytoplasm. In severely injured areas, endothelial integrity was completely destroyed and smooth muscle cells were proliferating and migrated to the endomembrane. Thus, we can conclude that Se or selenoproteins in the vascular wall plays an important role in cytoprotection against cholesterol oxide-induced vascular damage in rats.
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MESH Headings
- 6-Ketoprostaglandin F1 alpha/blood
- Animals
- Aorta/chemistry
- Cholestanols/pharmacology
- Cholesterol, HDL/blood
- Cholesterol, HDL/drug effects
- Cholesterol, LDL/blood
- Cholesterol, LDL/drug effects
- Cytoprotection/drug effects
- Disease Models, Animal
- Endothelins/blood
- Endothelins/drug effects
- Endothelium, Vascular/metabolism
- Endothelium, Vascular/pathology
- Glutathione Peroxidase/drug effects
- Glutathione Peroxidase/metabolism
- Hypolipidemic Agents/pharmacology
- Lipid Peroxides/blood
- Lipoproteins, LDL/pharmacology
- Lipoproteins, LDL/physiology
- Male
- Microscopy, Electron
- Microscopy, Electron, Scanning
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Rats
- Rats, Wistar
- Selenium/pharmacology
- Selenium/physiology
- Thromboxane B2/blood
- Triglycerides/blood
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Affiliation(s)
- Kaixun Huang
- Department of Chemistry, Huazhong University of Science and Technology, Wuhan, Hubei 430074, People's Republic of China.
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31
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Cholesterol oxidation products in irradiated raw meat with different packaging and storage time. Meat Sci 2001; 58:431-5. [DOI: 10.1016/s0309-1740(01)00046-8] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2000] [Revised: 01/22/2001] [Accepted: 01/22/2001] [Indexed: 11/21/2022]
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32
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Moreira EF, Jaworski C, Li A, Rodriguez IR. Molecular and biochemical characterization of a novel oxysterol-binding protein (OSBP2) highly expressed in retina. J Biol Chem 2001; 276:18570-8. [PMID: 11278871 DOI: 10.1074/jbc.m011259200] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We are interested in understanding the possible function(s) of the oxysterol-binding proteins in mediating oxysterol cytotoxicity in the retina. In this study we describe the cloning, localization, and biological activity of a novel oxysterol-binding protein (OSBP2), and complete the molecular characterization of the previously known OSBP1. Both OSBP genes contain 14 exons and have similar exon sizes and splice sites suggesting they may have arisen from a gene duplication event. OSBP1 is located in chromosome 11q12.1, and OSBP2 is located in 22q12. At the protein level they share 63% overall similarity and although they have unique N termini, both have similar pleckstrin homology domains within the N terminus region. Northern blot analyses indicate that OSBP1 is broadly expressed in human and monkey tissues. OSBP2 is detected mainly in retina, testis, and fetal liver. Western blot analysis using peptide antibodies specific to OSBP1 and OSBP2 detected the proteins in different subcellular fractions in the retinal monkey tissue. OSBP1 is detected mainly in the soluble or cytosolic fraction and nuclei whereas OSBP2 is detected exclusively in the detergent soluble fraction suggesting association with membranes. Immunohistochemical localization of OSBP1 and OSBP2 in the monkey retina placed these two proteins in similar but distinct areas of the inner retina. OSBP2 was found to bind 7-ketocholesterol but to have very little affinity for cholesterol or 25-hydroxycholesterol.
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Affiliation(s)
- E F Moreira
- Laboratory of Retinal Cell and Molecular Biology, National Eye Institute, National Institutes of Health, Bethesda, Maryland 20892, USA
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33
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Vaya J, Aviram M, Mahmood S, Hayek T, Grenadir E, Hoffman A, Milo S. Selective distribution of oxysterols in atherosclerotic lesions and human plasma lipoproteins. Free Radic Res 2001; 34:485-97. [PMID: 11378532 DOI: 10.1080/10715760100300431] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
The presence of oxidized sterols (oxysterols) in human serum and lesions has been linked to the initiation and progression of atherosclerosis. Data concerning the origin, identity and quantity of oxysterols in biological samples are controversial and inconsistent. This inconsistency may arise from different analytical methods or handling conditions used by different investigators. In the present study, oxysterol levels and distribution were analyzed by an optimized GC-MS method, in human atherosclerotic coronary and carotid lesions, in atherosclerotic apolipoprotein E deficient mice (E degrees mice) and in native and in vitro oxidized human low and high density lipoproteins. Oxysterol levels were analyzed with a limit of detection of 0.06 - 0.24 ng, with 25-hydroxycholesterol (25-OH) being the least sensitive. In human coronary and carotid lesions, obtained from endatherectomic samples, 27-hydroxycholesterol (27-OH) was the major oxysterol, with about 85% as sterols esterified to fatty acids. While total cholesterol and oxysterols levels were similar in both kinds of human lesions, oxysterol distribution was significantly different. In coronary lesions the mean levels of 27-OH and 7beta-hydroxycholesterol (7beta-OH) were 38% and 20% of total oxysterols, whereas in carotid lesions their mean levels were 66% and 5%, respectively. Unlike in human aortic lesions, 27-OH was entirely absent in E degrees mice, whereas the level of 7alpha-hydroxycholesterol (7alpha-OH) was 28% of the total oxysterols, vs. 5% in human coronary lesions. As 27-OH is an enzymatic product of cholesterol oxidation, this finding may indicate that such an enzymatic process does not take place in E degrees mice.
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Affiliation(s)
- J Vaya
- Laboratory of Natural Medicinal Compounds, Migal-Galilee Technological Center, Kiryat Shmona 10200, Israel
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34
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Razzazi-Fazeli E, Kleineisen S, Luf W. Determination of cholesterol oxides in processed food using high-performance liquid chromatography-mass spectrometry with atmospheric pressure chemical ionisation. J Chromatogr A 2000; 896:321-34. [PMID: 11093667 DOI: 10.1016/s0021-9673(00)00719-6] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The present work describes the development and application of an on-line atmospheric pressure ionisation (APCI) LC-MS interface for the simultaneous determination of seven toxicologically relevant cholesterol oxides (7alpha-hydroxycholesterol, 7beta-hydroxycholesterol, 25-hydroxycholesterol, 7-ketocholesterol, 5,6alpha-, 5,6beta-epoxycholesterol and cholestan-3beta,5alpha,6beta-triol). The HPLC method has been optimised to reach better separation of all tested compounds. The influences of APCI parameters (nebulising temperature, cone voltage, source temperature) on signal intensity and fragmentation pattern were investigated for all tested cholesterol oxides compounds. This is the first report on optimisation and determination of two compounds 7alpha-hydroxycholesterol and 5,6beta-epoxycholesterol in processed food using LC-MS. After extraction with hexane, clean-up was carried out using solid-phase extraction on a silica column. For the chromatographic separation of cholesterol oxides an Aquasil C18 column was used with acetonitrile-methanol (60:40) as mobile phase. For the first time we report the use of such a C18 column with a relatively hydrophilic nature for the separation of cholesterol oxides. APCI-MS detection was then applied in selected ion monitoring and positive ion modes by using the molecular ions and the main fragments. The developed method shows good linearity, high repeatability and good recovery for all tested cholesterol oxides. The method was applied for determination of seven selected cholesterol oxidation products in different foodstuffs such as butter, butteroil, lard and egg powder.
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Affiliation(s)
- E Razzazi-Fazeli
- Institute of Nutrition, University of Veterinary Medicine, Vienna, Austria.
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35
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Mahfouz MM, Kummerow FA. Cholesterol-rich diets have different effects on lipid peroxidation, cholesterol oxides, and antioxidant enzymes in rats and rabbits. J Nutr Biochem 2000; 11:293-302. [PMID: 10876104 DOI: 10.1016/s0955-2863(00)00083-8] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The objective of this study was to compare the effect of cholesterol feeding of rats and rabbits. The levels of lipid peroxidation products and oxysterols in the plasma of the two species plus the antioxidant enzyme activities in the liver and erythrocytes were measured to explain their different susceptibilities to atherosclerosis. Our study showed that rats are less susceptible than are rabbits to the atherogenic effect of a cholesterol-rich diet because of differences in lipid peroxidation products as well as antioxidant enzymes activities in their livers. In rabbits, cholesterol feeding produced severe hypercholesterolemia (43-fold increase) and increased plasma and liver lipid peroxidation. Total as well as the individual oxysterol contents of 7alpha-, 7beta-hydroxycholesterol, alpha-epoxy, beta-epoxycholesterol, cholestanetriol, 7-keto, and 27-hydroxycholesterol significantly increased in the plasma of hypercholesterolemic (HC) rabbits. Erythrocyte glutathione peroxidase (GSH-Px) activity significantly decreased whereas catalase activity significantly increased in HC rabbits. In rats cholesterol feeding increased the plasma cholesterol only twofold and had no effect on plasma or liver lipid peroxidation. Only 7alpha- and 7beta-hydroxycholesterol increased and no change was observed in any of the antioxidant enzymes activity in the erythrocytes. Although cholesterol feeding caused a 10-fold increase of liver cholesterol as ester in both rats and rabbits, the antioxidant enzyme GSH-Px and catalase activities in the liver significantly increased in rats but significantly decreased in rabbits. The increase of GSH-Px and catalase activities in the liver of cholesterol fed rats could have a protective role against oxidation, thus preventing the formation of lipid peroxidation and oxysterols.
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Affiliation(s)
- M M Mahfouz
- The Burnsides Research Laboratory, Urbana, IL 61801, USA
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36
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Zhou Q, Wasowicz E, Handler B, Fleischer L, Kummerow FA. An excess concentration of oxysterols in the plasma is cytotoxic to cultured endothelial cells. Atherosclerosis 2000; 149:191-7. [PMID: 10704631 DOI: 10.1016/s0021-9150(99)00343-3] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
To test if there is an excess concentration of oxysterols in the plasma of the patients with cardiovascular disease, we analyzed the oxysterol content in the plasma from 105 cardiac catheterized patients with angina and 80+/-8% stenosis in their coronary arteries. The result showed that the plasma contained a significantly higher concentration of oxysterols than did plasma from 105 age- and sex-matched, non-catheterized and angina-free controls (P<0.05). We used endothelial cells (ECs) cultured in medium containing either [3H]thymidine, [3H]mevalonolactone or 45Ca(2+) to determine how the plasma from the patients influences cell growth and function. We found that less [3H]thymidine (P<0.05), less [3H]mevalonolactone (P<0.05) and more 45Ca(2+) (P<0.001) was incorporated into ECs cultured in the plasma from 36 patients with 83+/-4% stenosis than from the 36 controls. When synthetic 7beta-hydroxycholesterol, cholesterol 5beta,6beta-epoxide, cholesterol 5alpha,6alpha-epoxide and 7-ketocholesterol were added to the plasma from the controls, the influx of 45Ca(2+) into ECs then equaled that in the plasma of patients. The enhanced incorporation of 45Ca(2+) into the ECs cultured in the plasma both from the patients and from controls with added synthetic oxysterols substantiates in vitro the hypothesis that oxysterols increase the influx of calcium into cells. These data indicated that an excess of oxysterols in the plasma of the patients was cytotoxic to the cultured cells.
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Affiliation(s)
- Q Zhou
- Harlan E. Moore Heart Research Foundation, Champaign, IL 61820, USA
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37
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Staprans I, Pan XM, Rapp JH, Grunfeld C, Feingold KR. Oxidized cholesterol in the diet accelerates the development of atherosclerosis in LDL receptor- and apolipoprotein E-deficient mice. Arterioscler Thromb Vasc Biol 2000; 20:708-14. [PMID: 10712395 DOI: 10.1161/01.atv.20.3.708] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The aim of the current study was to determine whether oxidized cholesterol in the diet accelerates atherosclerosis in low density lipoprotein receptor- (LDLR) and apolipoprotein E- (apo E) deficient mice. Mice were fed either a control diet or a diet containing oxidized cholesterol. For LDLR-deficient mice, the control diet consisted of regular mouse chow to which 1.0% cholesterol was added. The oxidized diet was identical to the control diet except that 5% of the added cholesterol was oxidized. In apo E-deficient mice, the control diet contained 0.15% cholesterol, whereas in the oxidized diet, 5% of the added cholesterol was oxidized. LDLR-deficient and apo E-deficient mice were fed the experimental diets for 7 and 4 months, respectively. In mice fed the oxidized-cholesterol diets, the levels of oxidized cholesterol in sera were increased. At the end of the experiment, aortas were removed and atherosclerosis was assessed. We found that in LDLR-deficient mice, feeding of an oxidized-cholesterol diet resulted in a 32% increase in fatty streak lesions (15.93+/-1.59% versus 21.00+/-1.38%, P<0.03). Similarly, in apo E-deficient mice, feeding of an oxidized-cholesterol diet increased fatty streak lesions by 38% (15.01+/-0.92% versus 20. 70+/-0.86%, P<0.001). The results of the current study thus demonstrate that oxidized cholesterol in the diet accelerates fatty streak lesion formation in both LDLR- and apo E-deficient mice.
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Affiliation(s)
- I Staprans
- Department of Veterans Affairs Medical Center, University of California, San Francisco 94121, USA.
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38
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Abstract
Oxygenated derivatives of cholesterol (oxysterols) present a remarkably diverse profile of biological activities, including effects on sphingolipid metabolism, platelet aggregation, apoptosis, and protein prenylation. The most notable oxysterol activities center around the regulation of cholesterol homeostasis, which appears to be controlled in part by a complex series of interactions of oxysterol ligands with various receptors, such as the oxysterol binding protein, the cellular nucleic acid binding protein, the sterol regulatory element binding protein, the LXR nuclear orphan receptors, and the low-density lipoprotein receptor. Identification of the endogenous oxysterol ligands and elucidation of their enzymatic origins are topics of active investigation. Except for 24, 25-epoxysterols, most oxysterols arise from cholesterol by autoxidation or by specific microsomal or mitochondrial oxidations, usually involving cytochrome P-450 species. Oxysterols are variously metabolized to esters, bile acids, steroid hormones, cholesterol, or other sterols through pathways that may differ according to the type of cell and mode of experimentation (in vitro, in vivo, cell culture). Reliable measurements of oxysterol levels and activities are hampered by low physiological concentrations (approximately 0.01-0.1 microM plasma) relative to cholesterol (approximately 5,000 microM) and by the susceptibility of cholesterol to autoxidation, which produces artifactual oxysterols that may also have potent activities. Reports describing the occurrence and levels of oxysterols in plasma, low-density lipoproteins, various tissues, and food products include many unrealistic data resulting from inattention to autoxidation and to limitations of the analytical methodology. Because of the widespread lack of appreciation for the technical difficulties involved in oxysterol research, a rigorous evaluation of the chromatographic and spectroscopic methods used in the isolation, characterization, and quantitation of oxysterols has been included. This review comprises a detailed and critical assessment of current knowledge regarding the formation, occurrence, metabolism, regulatory properties, and other activities of oxysterols in mammalian systems.
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Affiliation(s)
- G J Schroepfer
- Departments of Biochemistry, Rice University, Houston, Texas, USA.
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39
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Pirillo A, Zhu W, Roma P, Galli G, Caruso D, Pellegatta F, Catapano AL. Oxysterols from oxidized LDL are cytotoxic but fail to induce hsp70 expression in endothelial cells. FEBS Lett 1999; 462:113-6. [PMID: 10580102 DOI: 10.1016/s0014-5793(99)01497-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Oxidized low density lipoprotein (OxLDL) possesses several proatherogenic characteristics, among which a marked cytotoxicity. In vitro, cytotoxicity of OxLDL to endothelial cells is associated with an increase in the expression of the inducible form of heat shock protein 70 (hsp70), generally regarded as a cytoprotective protein. Oxidized derivatives of cholesterol which form upon LDL oxidation are cytotoxic. Moreover, most of the OxLDL cytotoxicity is due to its lipid moiety, in particular to oxysterols. In this report we demonstrate that although oxysterols identified in OxLDL are cytotoxic, they cannot trigger the increase in hsp70 expression observed with intact oxidized lipoproteins. We speculate therefore that oxysterols may represent the most toxic form of oxidized lipids in LDL because they cannot activate a rescue mechanism (i.e. the hsp response) and may contribute significantly to cell death within atherosclerotic plaques.
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Affiliation(s)
- A Pirillo
- Institute of Pharmacological Sciences, University of Milano, Via Balzaretti 9, 20133, Milano, Italy
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40
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Zarev S, Thérond P, Bonnefont-Rousselot D, Beaudeux JL, Gardès-Albert M, Legrand A. Major differences in oxysterol formation in human low density lipoproteins (LDLs) oxidized by *OH/O2*- free radicals or by copper. FEBS Lett 1999; 451:103-8. [PMID: 10371147 DOI: 10.1016/s0014-5793(99)00564-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The aim of our study was to determine the oxysterol formation in low density lipoproteins (LDLs) oxidized by defined oxygen free radicals (*OH/O2*-). This was compared to the oxysterol produced upon the classical copper oxidation procedure. The results showed a markedly lower formation of oxysterols induced by *OH/O2*- free radicals than by copper and thus suggested a poor ability of these radicals to initiate cholesterol oxidation in LDLs. Moreover, the molecular species of cholesteryl ester hydroperoxides produced by LDL copper oxidation seemed more labile than those formed upon *OH/O2*(-)-induced oxidation, probably due to their degradation by reaction with copper ions.
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Affiliation(s)
- S Zarev
- Laboratoire de Biochimie Métabolique et Clinique, Faculté de Pharmacie, Paris, France
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41
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Lizard G, Monier S, Cordelet C, Gesquière L, Deckert V, Gueldry S, Lagrost L, Gambert P. Characterization and comparison of the mode of cell death, apoptosis versus necrosis, induced by 7beta-hydroxycholesterol and 7-ketocholesterol in the cells of the vascular wall. Arterioscler Thromb Vasc Biol 1999; 19:1190-200. [PMID: 10323769 DOI: 10.1161/01.atv.19.5.1190] [Citation(s) in RCA: 145] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Oxidized low density lipoproteins (LDLs) play a central role in atherosclerosis, and their toxicity is due, at least in part, to the formation of oxysterols that have been shown to induce apoptosis in various cell types. As 7beta-hydroxycholesterol and 7-ketocholesterol are the major oxysterols found in oxidized LDLs, we have investigated and compared the mode of cell death, apoptosis versus necrosis, that they induce in the cells of the vascular wall, ie, endothelial cells, smooth muscle cells, and fibroblasts. To this end, human vascular endothelial cells from umbilical cord veins (HUVECs), human artery smooth muscle cells, A7R5 rat smooth muscle cells, MRC5 human fibroblasts, and human fibroblasts isolated from umbilical cord veins were taken at confluence and incubated for 48 hours with 7beta-hydroxycholesterol or 7-ketocholesterol (concentration range, 5 to 80 microg/mL). In all cells, both 7beta-hydroxycholesterol and 7-ketocholesterol exhibited toxic effects characterized by a loss of cell adhesion and an increased permeability to propidium iodide. In oxysterol-treated endothelial and smooth muscle cells, typical features of apoptosis were revealed: condensed and/or fragmented nuclei were detected by fluorescence microscopy after staining with Hoechst 33342, oligonucleosomal DNA fragments were visualized in situ in the cell nuclei by the TdT-mediated dUTP-biotin nick-end labeling (TUNEL) method, and internucleosomal DNA fragmentation was found on agarose gel. In contrast, in oxysterol-treated fibroblasts, fragmented and/or condensed nuclei were never revealed, and no DNA fragmentation was observed either by the TUNEL method or by DNA analysis on agarose gel, indicating that these oxysterols induced necrosis in these cells but not apoptosis. In addition, acetylated Asp-Glu-Val-L-aspartic acid aldehyde (an inhibitor of Asp-Glu-Val-L-aspartic acid-sensitive caspases) prevented 7beta-hydroxycholesterol- and 7-ketocholesterol-induced cell death in HUVECs and smooth muscle cells but not in fibroblasts. Thus, 7beta-hydroxycholesterol and 7-ketocholesterol have dual cytotoxic effects on the cells of the vascular wall by their ability to induce apoptosis in endothelial and smooth muscle cells and necrosis in fibroblasts.
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MESH Headings
- Animals
- Apoptosis/drug effects
- Benzimidazoles
- Caspases/metabolism
- Cell Adhesion
- Cell Count
- Cell Death/drug effects
- Cells, Cultured
- Cysteine Proteinase Inhibitors/pharmacology
- DNA Fragmentation
- Endothelium, Vascular/cytology
- Endothelium, Vascular/drug effects
- Ethanol/pharmacology
- Fibroblasts/drug effects
- Fluorescent Dyes
- Humans
- Hydroxycholesterols/pharmacology
- In Situ Nick-End Labeling
- Ketocholesterols/pharmacology
- Lipoproteins, LDL/chemistry
- Lipoproteins, LDL/toxicity
- Microscopy, Fluorescence
- Microscopy, Phase-Contrast
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Necrosis
- Oligopeptides/pharmacology
- Rats
- Umbilical Arteries/cytology
- Umbilical Veins/cytology
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Affiliation(s)
- G Lizard
- Laboratoire de Biochimie des Lipoprotéines, INSERM U 498, Faculté de Médecine, Dijon, France.
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42
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Abstract
Oxysterols are present in human atherosclerotic plaque and are suggested to play an active role in plaque development. Moreover, the oxysterol:cholesterol ratio in plaque is much higher than in normal tissues or plasma. Oxysterols in plaque are derived both non-enzymically, either from the diet and/or from in vivo oxidation, or (e.g. 27-hydroxycholesterol) are formed enzymically during cholesterol catabolism. While undergoing many of the same reactions as cholesterol, such as being esterified by cells and in plasma, certain oxysterols in some animal and in vitro models exhibit far more potent effects than cholesterol per se. In vitro, oxysterols perturb several aspects of cellular cholesterol homeostasis (including cholesterol biosynthesis, esterification, and efflux), impair vascular reactivity and are cytotoxic and/or induce apoptosis. Injection of relatively large doses of oxysterols into animals causes acute angiotoxicity whereas oxysterol-feeding experiments have yielded contrary results as far as their atherogenicity is concerned. There is no direct evidence yet in humans that oxysterols contribute to atherogenesis. However, oxysterol levels are elevated in human low-density lipoprotein (LDL) subfractions that are considered potentially atherogenic and two recent studies have indicated that raised plasma levels of a specific oxysterol (7beta-hydroxycholesterol) may be associated with an increased risk of atherosclerosis. At the present time there are a number of significant and quite widespread problems with current literature which preclude more than a tentative suggestion that oxysterols have a causal role in atherogenesis. Further studies are necessary to definitively determine the role of oxysterols in atherosclerosis, and considering the wide-ranging tissue levels reported in the literature, special emphasis is needed on their accurate analysis, especially in view of the susceptibility of the parent cholesterol to artifactual oxidation.
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Affiliation(s)
- A J Brown
- Cell Biology Group, Heart Research Institute, Sydney, NSW, Australia. brown&
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43
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Rong JX, Rangaswamy S, Shen L, Dave R, Chang YH, Peterson H, Hodis HN, Chisolm GM, Sevanian A. Arterial injury by cholesterol oxidation products causes endothelial dysfunction and arterial wall cholesterol accumulation. Arterioscler Thromb Vasc Biol 1998; 18:1885-94. [PMID: 9848880 DOI: 10.1161/01.atv.18.12.1885] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Cholesterol oxidation products (ChOx) have been reported to cause acute vascular injury in vivo; however, the pharmacokinetics of ChOx after administration and the mechanisms by which they cause chronic vascular injury are not well understood. To further study the pharmacokinetics and atherogenic properties of ChOx, New Zealand White rabbits were injected intravenously (70 mg per injection, 20 injections per animal) with a ChOx mixture having a composition similar to that found in vivo during a 70-day period. Total ChOx concentrations in plasma peaked almost immediately after a single injection, declined rapidly, and returned to preinjection levels in 2 hours. After multiple injections, the ChOx concentrations rose gradually to levels 2- to 3-fold above baseline levels, increasing mostly in the cholesteryl ester fraction of LDL and VLDL. Rabbit serum and the isolated LDL/VLDL fraction containing elevated ChOx concentrations were cytotoxic to V79 fibroblasts and rabbit aortic endothelial cells. At the time of killing, cholesterol levels in the aortas from ChOx-injected rabbits were significantly elevated despite the fact that plasma cholesterol levels remained in the normal range. In addition, aortas from the ChOx-injected rabbits retained more 125I-labeled horseradish peroxidase, measured 20 minutes after intravenous injection. Transmural concentration profiles across the arterial wall also showed increased horseradish peroxidase accumulation in the inner half of the media from the thoracic aorta in ChOx-injected rabbits. In conclusion, ChOx injection resulted in accumulation of circulating ChOx and induced increased vascular permeability and accumulation of lipids and macromolecules. This study reveals that even under normocholesterolemic conditions, ChOx can cause endothelial dysfunction, increased macromolecular permeability, and increased cholesterol accumulation, parameters believed to be involved in the development of early atherosclerotic lesions.
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Affiliation(s)
- J X Rong
- Department of Pathology, Division of Cardiology, and Atherosclerosis Research Unit, School of Medicine, Los Angeles, CA, USA
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44
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Vine D, Mamo J, Beilin L, Mori T, Croft K. Dietary oxysterols are incorporated in plasma triglyceriderich lipoproteins, increase their susceptibility to oxidation and increase aortic cholesterol concentration of rabbits. J Lipid Res 1998. [DOI: 10.1016/s0022-2275(20)32498-6] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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45
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Pikuleva IA, Babiker A, Waterman MR, Björkhem I. Activities of recombinant human cytochrome P450c27 (CYP27) which produce intermediates of alternative bile acid biosynthetic pathways. J Biol Chem 1998; 273:18153-60. [PMID: 9660774 DOI: 10.1074/jbc.273.29.18153] [Citation(s) in RCA: 92] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The primary physiological significance of cytochrome P450c27 (CYP27) has been associated with its role in the degradation of the side chain of C27 steroids in the hepatic bile acid biosynthesis pathway, which begins with 7alpha-hydroxylation of cholesterol in liver. However, recognition that in humans P450c27 is a widely or ubiquitously expressed mitochondrial P450, and that there are alternative pathways of bile acid synthesis which begin with 27-hydroxylation of cholesterol catalyzed by P450c27, suggests the need to reevaluate the role of this enzyme and its catalytic properties. 27-Hydroxycholesterol was thought to be the only product formed upon reaction of P450c27 with cholesterol. However, the present study demonstrates that recombinant human P450c27 is also able to further oxidize 27-hydroxycholesterol giving first an aldehyde and then 3beta-hydroxy-5-cholestenoic acid. Kinetic data indicate that in a reconstituted system, after 27-hydroxycholesterol is formed from cholesterol, it is released from the P450 and then competes with cholesterol for reentry the enzyme active site for further oxidation. Under subsaturating substrate concentrations, the efficiencies of oxidation of 27-hydroxycholesterol and 3beta-hydroxy-5-cholestenal to the acid by human P450c27 are greater than the efficiency of hydroxylation of cholesterol to 27-hydroxycholesterol indicating that the first hydroxylation step in the overall conversion of cholesterol into 3beta-hydroxy-5-cholestenoic acid is rate-limiting. Interestingly, 3beta-hydroxy-5-cholestenoic acid was found to be further metabolized by the recombinant human P450c27, giving two monohydroxylated products with the hydroxyl group introduced at different positions on the steroid nucleus.
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Affiliation(s)
- I A Pikuleva
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0146, USA
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46
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Yuan YV, Kitts DD, Godin DV. Interactive effects of increased intake of saturated fat and cholesterol on atherosclerosis in the Japanese quail (Coturnix japonica). Br J Nutr 1998; 80:89-100. [PMID: 9797648 DOI: 10.1017/s0007114598001810] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Increasing the energy value of diets with dietary fat, particularly fats rich in saturated fatty acids, can result in the elevation of plasma total and lipoprotein cholesterol. In the present study, experimental diets were designed to examine the effects of increasing the energy content of diets with a saturated fat source and cholesterol in a non-purified diet on hyperlipoproteinaemia and aortic plaque composition in the atherosclerosis-susceptible Japanese quail (Coturnix japonica) model of human atherosclerosis. Commercial poultry diets containing two levels (i.e. 60 or 120 g/kg) of beef tallow as the primary source of saturated fat were balanced for endogenous cholesterol or supplemented with cholesterol (i.e. 0.5 or 5.0 g/kg) and fed to quail for 9 weeks to examine the effects on whole plasma, lipoprotein and aortic plaque lipid composition in relation to aortic plaque formation. Hypercholesterolaemia (P < 0.001) was confirmed in birds fed on high-cholesterol (HC) diets only. An interaction (P = 0.05) between dietary cholesterol and fat intake level was observed for plasma triacylglycerols (TG) and was specific to changes observed in VLDL composition. Diet-induced changes in lipoprotein total cholesterol, TG and phospholipid composition were greatest in the portomicron and VLDL fractions in birds fed on atherogenic diets. Hyperlipoproteinaemia induced by the 60 g/kg added beef tallow-HC diet resulted in significant (P < 0.001) aortic plaque deposition, which was further enhanced in birds fed on the 120 g/kg beef tallow-HC diet. Quail fed on 120 g/kg beef tallow-HC diets exhibited the most severe aortic plaque formation, with marked increases in aortic tissue cholesterol content and quantifiable amounts of several cholesterol oxides (5,6 alpha-epoxy-5 alpha-cholesterol, 7 beta-hydroxycholesterol, cholestanetriol, 7-ketocholesterol and 25-hydroxycholesterol). In summary, hyperlipoproteinaemia associated with HC diets with a greater proportion of energy from saturated fat produced a combined effect in altering plasma and lipoprotein lipid composition as well as aortic tissue cholesterol and cholesterol oxide content in the Japanese quail.
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Affiliation(s)
- Y V Yuan
- Department of Food Science, Faculty of Agricultural Sciences, University of British Columbia, Vancouver, Canada
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47
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Staprans I, Pan XM, Rapp JH, Feingold KR. Oxidized cholesterol in the diet accelerates the development of aortic atherosclerosis in cholesterol-fed rabbits. Arterioscler Thromb Vasc Biol 1998; 18:977-83. [PMID: 9633940 DOI: 10.1161/01.atv.18.6.977] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Oxidized lipoproteins may play a role in atherosclerosis. Recently, we have demonstrated that the levels of oxidized fatty acids in the circulation correlate directly with the quantity of oxidized fatty acids in the diet and that dietary oxidized fatty acids accelerate atherosclerosis in rabbits. The present study tests the hypothesis that oxidized cholesterol in the diet accelerates the development of atherosclerosis. Rabbits were fed a diet containing 0.33% nonoxidized cholesterol (control diet) or the same diet containing 0.33% cholesterol of which 5% was oxidized (oxidized diet). Serum cholesterol levels increased to a similar extent in both groups, with the majority of cholesterol in the beta-VLDL fraction. Moreover, in the serum beta-VLDL fraction and liver, there was a significant increase in the oxidized cholesterol levels. Most importantly, feeding a diet enriched in oxidized cholesterol resulted in a 100% increase in fatty streak lesions in the aorta. Western diets contain high concentrations of oxidized cholesterol products, and our results suggest that these foods may be a risk factor for atherosclerosis.
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Affiliation(s)
- I Staprans
- Department of Veterans Affairs Medical Center, University of California, San Francisco, USA
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48
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Careri M, Ferretti D, Manini P, Musci M. Evaluation of particle beam high-performance liquid chromatography–mass spectrometry for analysis of cholesterol oxides. J Chromatogr A 1998. [DOI: 10.1016/s0021-9673(97)00764-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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49
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Yuan YV, Kitts DD, Godin DV. Influence of dietary cholesterol and fat source on atherosclerosis in the Japanese quail (Coturnix japonica). Br J Nutr 1997; 78:993-1014. [PMID: 9497448 DOI: 10.1079/bjn19970214] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The Japanese quail has been used as a model of human atherosclerosis to investigate the mechanisms underlying the development of vascular lesions, i.e. hyperlipoproteinaemia and impaired endogenous antioxidant status. In the present study, Japanese quail were fed on semi-purified diets containing butter, beef tallow or soyabean-oil blends, with either 0.5 or 5 g cholesterol/kg for 9 weeks to examine the effects of dietary fat blends varying in fatty acid composition and cholesterol intake on plasma lipids and aortic atherosclerotic plaque and sterol composition. These findings were related to possible diet-induced changes in antioxidant status of selected tissues. Hypercholesterolaemia was confirmed (P < 0.001) in birds fed on high-cholesterol (HC) diets. Plasma total cholesterol concentration and cholesterol content of lipoprotein fractions in hypercholesterolaemic birds were lower (P < 0.05) in quail fed on the soyabean-oil blend. Plasma triacylglycerol content was increased (P < 0.001) in HC-fed birds. Dietary fat blends did not influence plasma triacylglycerol levels. Tissue antioxidant status (catalase (EC 1.11.1.6), glutathione peroxidase (EC 1.11.1.9), glutathione reductase (EC 1.6.4.1) and superoxide dismutase (EC 1.15.1.1) activities and glutathione content) was generally not greatly affected by dietary fat blend or cholesterol treatment. Birds fed on HC diets exhibited severe (P < 0.001) atherosclerotic plaque in aortas which was not influenced by the source of dietary fat blend. Scanning electron microscopy confirmed results of visual aortic plaque scoring using dissecting light microscopy. Several cholesterol oxides were identified and quantified in aortic plaque from HC-fed birds (5,6 alpha-epoxy-5 alpha-cholesterol, 7(beta-hydroxycholesterol and 7-ketocholesterol) regardless of dietary fat blend. The results indicate that dietary fat blends varying in polyunsaturated:saturated fatty acid ratios only marginally influence the degree of hypercholesterolaemia in atherosclerosis-susceptible quail fed on atherogenic diets only, and are not a factor, compared with sterol feeding, in modulating the degree of atherosclerosis or the aortic oxysterol content in these same birds. Moreover, diet-induced hyperlipoproteinaemia had only a small effect on antioxidant status of selected tissues examined.
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Affiliation(s)
- Y V Yuan
- Department of Food Science, University of British Columbia, Vancouver, Canada
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50
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Wilson AM, Sisk RM, O'Brien NM. Modulation of cholestane-3 beta,5 alpha,6 beta-triol toxicity by butylated hydroxytoluene, alpha-tocopherol and beta-carotene in newborn rat kidney cells in vitro. Br J Nutr 1997; 78:479-92. [PMID: 9306888 DOI: 10.1079/bjn19970165] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Cholesterol oxidation products (COP) have been reported to influence vital cellular processes such as cell growth, cell proliferation, membrane function and de novo sterol biosynthesis. The objectives of the present study were: (1) to develop an in vitro model using newborn rat kidney (NRK) cells to investigate the actions of COP; (2) to investigate the effect of COP on cell viability, endogenous antioxidant enzymes activities, i.e. superoxide dismutase (EC 1.15.1.1; SOD) and catalase (EC 1.11.1.6; CAT), and the extent of lipid peroxidation in this model; (3) to determine whether the addition of 100-1000 nM-alpha-tocopherol, beta-carotene or butylated hydroxytoluene (BHT) could protect against COP-induced cytotoxicity. NRK cells were cultured in the presence of various concentrations (5-50 microM) of cholesterol or cholestane-3 beta,5 alpha,6 beta-triol (cholestantriol) for a period of 24 h. Cholesterol over the range 5-50 microM did not induce cytotoxicity as indicated by the neutral-red-uptake assay or the lactate dehydrogenase (EC 1.1.1.27)-release assay. However, cell viability was compromised by the addition of > 10 microM-cholestantriol (P < 0.05). The addition of beta-carotene (100-1000 nM) did not increase cell viability significantly in cholestantriol-supplemented cells. However, the addition of alpha-tocopherol (1000 nM) and BHT (1000 nM) significantly increased percentage cell viability above that of the cholestantriol-supplemented cells but not back to control levels. SOD and CAT activities in NRK cells significantly decreased (P < 0.05) following incubation with cholestantriol. The addition of > 750 nM-alpha-tocopherol, beta-carotene or BHT returned SOD and CAT activities to that of the control. Lipid peroxidation was significantly induced (P < 0.05) in the presence of cholestantriol. Supplementation of the cells with alpha-tocopherol (250, 500 or 1000 nM) or BHT (750 or 1000 nM) resulted in a reduction in the extent of lipid peroxidation (P < 0.05). The addition of beta-carotene over the concentration range of 250-1000 nM did not reduce lipid peroxidation significantly compared with cells exposed to cholestantriol alone. These findings suggest that addition of exogenous antioxidants may be beneficial in the prevention of COP-induced toxicity in vitro.
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Affiliation(s)
- A M Wilson
- Department of Nutrition, National Food Biotechnology Centre, University College, Cork, Republic of Ireland
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