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Kirk LM, Waits CMK, Bashore AC, Dosso B, Meyers AK, Renaldo AC, DePalma TJ, Simms KN, Hauser N, Chuang Key CC, McCall CE, Parks JS, Sergeant S, Langefeld CD, Skardal A, Rahbar E. Exploiting three-dimensional human hepatic constructs to investigate the impact of rs174537 on fatty acid metabolism. PLoS One 2022; 17:e0262173. [PMID: 35051193 PMCID: PMC8775235 DOI: 10.1371/journal.pone.0262173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Accepted: 12/16/2021] [Indexed: 11/18/2022] Open
Abstract
The Modern Western Diet has been associated with the rise in metabolic and inflammatory diseases, including obesity, diabetes, and cardiovascular disease. This has been attributed, in part, to the increase in dietary omega-6 polyunsaturated fatty acid (PUFA) consumption, specifically linoleic acid (LA), arachidonic acid (ARA), and their subsequent metabolism to pro-inflammatory metabolites which may be driving human disease. Conversion of dietary LA to ARA is regulated by genetic variants near and within the fatty acid desaturase (FADS) haplotype block, most notably single nucleotide polymorphism rs174537 is strongly associated with FADS1 activity and expression. This variant and others within high linkage disequilibrium may potentially explain the diversity in both diet and inflammatory mediators that drive chronic inflammatory disease in human populations. Mechanistic exploration into this phenomenon using human hepatocytes is limited by current two-dimensional culture models that poorly replicate in vivo functionality. Therefore, we aimed to develop and characterize a three-dimensional hepatic construct for the study of human PUFA metabolism. Primary human hepatocytes cultured in 3D hydrogels were characterized for their capacity to represent basic lipid processing functions, including lipid esterification, de novo lipogenesis, and cholesterol efflux. They were then exposed to control and LA-enriched media and reproducibly displayed allele-specific metabolic activity of FADS1, based on genotype at rs174537. Hepatocytes derived from individuals homozygous with the minor allele at rs174537 (i.e., TT) displayed the slowest metabolic conversion of LA to ARA and significantly reduced FADS1 and FADS2 expression. These results support the feasibility of using 3D human hepatic cultures for the study of human PUFA and lipid metabolism and relevant gene-diet interactions, thereby enabling future nutrition targets in humans.
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Affiliation(s)
- L. Madison Kirk
- Department of Biomedical Engineering, Wake Forest School of Medicine, Winston-Salem, North Carolina, United States of America
- Virginia Tech – Wake Forest University, School of Biomedical Engineering and Sciences, Blacksburg, Virginia, United States of America
| | - Charlotte Mae K. Waits
- Department of Biomedical Engineering, Wake Forest School of Medicine, Winston-Salem, North Carolina, United States of America
- Virginia Tech – Wake Forest University, School of Biomedical Engineering and Sciences, Blacksburg, Virginia, United States of America
| | - Alexander C. Bashore
- Division of Cardiology, Department of Medicine, Columbia University Irving Medical Center, New York, New York, United States of America
- Department of Internal Medicine, Section of Molecular Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina, United States of America
| | - Beverly Dosso
- Department of Integrative Physiology & Pharmacology, Wake Forest School of Medicine, Winston-Salem, North Carolina, United States of America
| | - Allison K. Meyers
- Department of Internal Medicine, Section of Molecular Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina, United States of America
- Department of Microbiology and Immunology, Wake Forest School of Medicine, Winston-Salem, North Carolina, United States of America
| | - Antonio C. Renaldo
- Department of Biomedical Engineering, Wake Forest School of Medicine, Winston-Salem, North Carolina, United States of America
- Virginia Tech – Wake Forest University, School of Biomedical Engineering and Sciences, Blacksburg, Virginia, United States of America
| | - Thomas J. DePalma
- Department of Biomedical Engineering, The Ohio State University, Columbus, Ohio, United States of America
| | - Kelli N. Simms
- Department of Biomedical Engineering, Wake Forest School of Medicine, Winston-Salem, North Carolina, United States of America
- Virginia Tech – Wake Forest University, School of Biomedical Engineering and Sciences, Blacksburg, Virginia, United States of America
| | - Nathaniel Hauser
- Department of Biomedical Engineering, Wake Forest School of Medicine, Winston-Salem, North Carolina, United States of America
- Virginia Tech – Wake Forest University, School of Biomedical Engineering and Sciences, Blacksburg, Virginia, United States of America
| | - Chia-Chi Chuang Key
- Department of Internal Medicine, Section of Molecular Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina, United States of America
| | - Charles E. McCall
- Department of Internal Medicine, Section of Molecular Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina, United States of America
| | - John S. Parks
- Department of Internal Medicine, Section of Molecular Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina, United States of America
| | - Susan Sergeant
- Department of Biochemistry, Wake Forest School of Medicine, Winston-Salem, North Carolina, United States of America
| | - Carl D. Langefeld
- Department of Biostatistics and Data Science, Wake Forest School of Medicine, Winston-Salem, North Carolina, United States of America
- Center for Precision Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina, United States of America
| | - Aleksander Skardal
- Department of Biomedical Engineering, The Ohio State University, Columbus, Ohio, United States of America
| | - Elaheh Rahbar
- Department of Biomedical Engineering, Wake Forest School of Medicine, Winston-Salem, North Carolina, United States of America
- Virginia Tech – Wake Forest University, School of Biomedical Engineering and Sciences, Blacksburg, Virginia, United States of America
- Center for Precision Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina, United States of America
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Bashore AC, Liu M, Key CCC, Boudyguina E, Wang X, Carroll CM, Sawyer JK, Mullick AE, Lee RG, Macauley SL, Parks JS. Targeted Deletion of Hepatocyte Abca1 Increases Plasma HDL (High-Density Lipoprotein) Reverse Cholesterol Transport via the LDL (Low-Density Lipoprotein) Receptor. Arterioscler Thromb Vasc Biol 2019; 39:1747-1761. [PMID: 31167565 DOI: 10.1161/atvbaha.119.312382] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
OBJECTIVE The role of hepatocyte Abca1 (ATP binding cassette transporter A1) in trafficking hepatic free cholesterol (FC) into plasma versus bile for reverse cholesterol transport (RCT) is poorly understood. We hypothesized that hepatocyte Abca1 recycles plasma HDL-C (high-density lipoprotein cholesterol) taken up by the liver back into plasma, maintaining the plasma HDL-C pool, and decreasing HDL-mediated RCT into feces. Approach and Results: Chow-fed hepatocyte-specific Abca1 knockout (HSKO) and control mice were injected with human HDL radiolabeled with 125I-tyramine cellobiose (125I-TC; protein) and 3H-cholesteryl oleate (3H-CO). 125I-TC and 3H-CO plasma decay, plasma HDL 3H-CO selective clearance (ie, 3H-125I fractional catabolic rate), liver radiolabel uptake, and fecal 3H-sterol were significantly greater in HSKO versus control mice, supporting increased plasma HDL RCT. Twenty-four hours after 3H-CO-HDL injection, HSKO mice had reduced total hepatic 3H-FC (ie, 3H-CO hydrolyzed to 3H-FC in liver) resecretion into plasma, demonstrating Abca1 recycled HDL-derived hepatic 3H-FC back into plasma. Despite similar liver LDLr (low-density lipoprotein receptor) expression between genotypes, HSKO mice treated with LDLr-targeting versus control antisense oligonucleotide had slower plasma 3H-CO-HDL decay, reduced selective 3H-CO clearance, and decreased fecal 3H-sterol excretion that was indistinguishable from control mice. Increased RCT in HSKO mice was selective for 3H-CO-HDL, since macrophage RCT was similar between genotypes. CONCLUSIONS Hepatocyte Abca1 deletion unmasks a novel and selective FC trafficking pathway that requires LDLr expression, accelerating plasma HDL-selective CE uptake by the liver and promoting HDL RCT into feces, consequently reducing HDL-derived hepatic FC recycling into plasma.
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Affiliation(s)
- Alexander C Bashore
- From the Department of Internal Medicine, Section of Molecular Medicine (A.C.B., M.L., C-C.C.K., E.B., X.W., J.K.S., J.S.P.), Wake Forest School of Medicine, Winston-Salem, NC
| | - Mingxia Liu
- From the Department of Internal Medicine, Section of Molecular Medicine (A.C.B., M.L., C-C.C.K., E.B., X.W., J.K.S., J.S.P.), Wake Forest School of Medicine, Winston-Salem, NC
| | - Chia-Chi C Key
- From the Department of Internal Medicine, Section of Molecular Medicine (A.C.B., M.L., C-C.C.K., E.B., X.W., J.K.S., J.S.P.), Wake Forest School of Medicine, Winston-Salem, NC
| | - Elena Boudyguina
- From the Department of Internal Medicine, Section of Molecular Medicine (A.C.B., M.L., C-C.C.K., E.B., X.W., J.K.S., J.S.P.), Wake Forest School of Medicine, Winston-Salem, NC
| | - Xianfeng Wang
- From the Department of Internal Medicine, Section of Molecular Medicine (A.C.B., M.L., C-C.C.K., E.B., X.W., J.K.S., J.S.P.), Wake Forest School of Medicine, Winston-Salem, NC
| | - Caitlin M Carroll
- Department of Internal Medicine, Section on Gerontology and Geriatric Medicine (C.M.C., S.L.M.), Wake Forest School of Medicine, Winston-Salem, NC
| | - Janet K Sawyer
- From the Department of Internal Medicine, Section of Molecular Medicine (A.C.B., M.L., C-C.C.K., E.B., X.W., J.K.S., J.S.P.), Wake Forest School of Medicine, Winston-Salem, NC
| | - Adam E Mullick
- Cardiovascular, Renal and Metabolic Group, Department of Antisense Drug Discovery, Ionis Pharmaceuticals, Inc, Carlsbad, CA (A.E.M., R.G.L.)
| | - Richard G Lee
- Cardiovascular, Renal and Metabolic Group, Department of Antisense Drug Discovery, Ionis Pharmaceuticals, Inc, Carlsbad, CA (A.E.M., R.G.L.)
| | - Shannon L Macauley
- Department of Internal Medicine, Section on Gerontology and Geriatric Medicine (C.M.C., S.L.M.), Wake Forest School of Medicine, Winston-Salem, NC
| | - John S Parks
- From the Department of Internal Medicine, Section of Molecular Medicine (A.C.B., M.L., C-C.C.K., E.B., X.W., J.K.S., J.S.P.), Wake Forest School of Medicine, Winston-Salem, NC
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3
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Vrins CLJ, Ottenhoff R, van den Oever K, de Waart DR, Kruyt JK, Zhao Y, van Berkel TJC, Havekes LM, Aerts JM, van Eck M, Rensen PCN, Groen AK. Trans-intestinal cholesterol efflux is not mediated through high density lipoprotein. J Lipid Res 2012; 53:2017-2023. [PMID: 22802462 DOI: 10.1194/jlr.m022194] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Transintestinal cholesterol efflux (TICE) provides an attractive target to increase body cholesterol excretion. At present, the cholesterol donor responsible for direct delivery of plasma cholesterol to the intestine is unknown. In this study, we investigated the role of HDL in TICE. ATP-binding cassette protein A1 deficient (Abca1(-/-)) mice that lack HDL and wild-type (WT) mice were intravenously injected with chylomicron-like emulsion particles that contained radiolabeled cholesterol that is liberated in the liver and partly reenters the circulation. Both groups secreted radiolabeled cholesterol from plasma into intestinal lumen and TICE was unaltered between the two mouse models. To further investigate the role of HDL, we injected HDL with radiolabeled cholesterol in WT mice and Abca1(-/-)×Sr-b1(-/-) mice that lack HDL and are also unable to clear HDL via the liver. The intestines of both mice were unable to take up and secrete radiolabeled cholesterol from HDL via TICE. Although a generally accepted major player in the hepatobiliary route-based cholesterol excretion, HDL plays no significant role in TICE in mice.
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Affiliation(s)
- Carlos L J Vrins
- Department of Medical Biochemistry, Amsterdam, The Netherlands; AMC Tytgat Institute, Academic Medical Center, Amsterdam, The Netherlands
| | | | | | - Dirk R de Waart
- AMC Tytgat Institute, Academic Medical Center, Amsterdam, The Netherlands
| | - J Kar Kruyt
- Division of Biopharmaceutics, Leiden/Amsterdam Center for Drug Research, Leiden University, Leiden, The Netherlands
| | - Ying Zhao
- Division of Biopharmaceutics, Leiden/Amsterdam Center for Drug Research, Leiden University, Leiden, The Netherlands
| | - Theo J C van Berkel
- Division of Biopharmaceutics, Leiden/Amsterdam Center for Drug Research, Leiden University, Leiden, The Netherlands
| | - Louis M Havekes
- Department of General Internal Medicine, Endocrinology and Metabolic Diseases, Leiden University Medical Center, Leiden, The Netherlands; and
| | | | - Miranda van Eck
- Division of Biopharmaceutics, Leiden/Amsterdam Center for Drug Research, Leiden University, Leiden, The Netherlands
| | - Patrick C N Rensen
- Department of General Internal Medicine, Endocrinology and Metabolic Diseases, Leiden University Medical Center, Leiden, The Netherlands; and
| | - Albert K Groen
- Department of Pediatrics/Laboratory Medicine, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
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4
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Fusegawa Y, Kelley KL, Sawyer JK, Shah RN, Rudel LL. Influence of dietary fatty acid composition on the relationship between CETP activity and plasma lipoproteins in monkeys. J Lipid Res 2001. [DOI: 10.1016/s0022-2275(20)31511-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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5
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Thomas MJ, Chen Q, Zabalawi M, Anderson R, Wilson M, Weinberg R, Sorci-Thomas MG, Rudel LL. Is the oxidation of high-density lipoprotein lipids different than the oxidation of low-density lipoprotein lipids? Biochemistry 2001; 40:1719-24. [PMID: 11327832 DOI: 10.1021/bi0022442] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
This article gives detailed insight into the kinetics of high-density lipoprotein (HDL) oxidation catalyzed by azobis(2-amidinopropane).dihydrochloride (ABAP) or by copper. ABAP initialized oxidation of human HDL 3-4 times faster than non-human primate HDL with a similar composition. The oxidizability of non-human primate HDL was 1000 times lower than the oxidizability calculated from rate constants derived from liposome oxidation, suggesting that there is a slow step in HDL oxidation not present in liposomes. Saturable binding of copper to HDL was a significant feature of copper-catalyzed oxidation. Binding constants (K(m)) for non-human primate HDL were 2-3-fold lower than those for human HDL. Copper-catalyzed oxidation of non-human primate HDL was slower than that of human HDL, but human HDL(2) and HDL(3) oxidized at about the same rate. Overall, the kinetics describing the oxidation of HDL were mechanistically similar to those reported for LDL, suggesting that HDL lipids were as easily oxidized as LDL lipids and that HDL will be easily oxidized in vivo when exposed to agents that oxidize LDL.
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Affiliation(s)
- M J Thomas
- Department of Biochemistry, Wake Forest University School of Medicine, Medical Center Blvd., Winston-Salem, NC 27157, USA.
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6
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Williams DL, Connelly MA, Temel RE, Swarnakar S, Phillips MC, de la Llera-Moya M, Rothblat GH. Scavenger receptor BI and cholesterol trafficking. Curr Opin Lipidol 1999; 10:329-39. [PMID: 10482136 DOI: 10.1097/00041433-199908000-00007] [Citation(s) in RCA: 141] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Scavenger receptor BI (SR-BI) mediates the selective uptake of HDL cholesteryl ester into steroidogenic cells and the liver and is a major determinant of the plasma HDL concentration in the mouse. Recent studies indicate that SR-BI also alters the metabolism of apolipoprotein B-containing particles and influences the development of atherosclerosis in several animal models. These results and the similar pattern of SR-BI expression in humans emphasize that it is important to learn how this receptor influences lipoprotein metabolism and atherosclerosis in people.
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Affiliation(s)
- D L Williams
- Department of Pharmacological Sciences, University Medical Centre, State University of New York at Stony Brook, 11794, USA.
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7
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Cheng B, Kowal J. Analysis of adrenal cholesteryl esters by reversed phase high performance liquid chromatography. J Lipid Res 1994. [DOI: 10.1016/s0022-2275(20)40107-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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8
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Kim DH, Lee KJ, Heo GS. Analysis of cholesterol and cholesteryl esters in human serum using capillary supercritical fluid chromatography. JOURNAL OF CHROMATOGRAPHY. B, BIOMEDICAL APPLICATIONS 1994; 655:1-8. [PMID: 8061816 DOI: 10.1016/0378-4347(94)00032-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Capillary supercritical fluid chromatography (SFC) using carbon dioxide as a mobile phase was applied for the determination of free cholesterol and cholesteryl esters in human serum. Serum samples were extracted with methanol-chloroform (2:1, v/v), and the extracts were analyzed by pressure programmed capillary SFC-flame-ionization detection (FID) without thermal degradation and derivatization. The total cholesterol concentrations obtained from SFC analysis were compared with those from GC or enzymatic analysis. The capillary SFC-FID method having high resolution gave an acceptable average relative standard deviation of 2.6%, and a detection limit of 4-6 pg. The quantitative results were acceptable for the simultaneous analysis of cholesterol and its esters in biological fluids. The concentration profiles of each compound in various samples, normal Korean human serum, Western human serum, and from high-cholesterol patient plasma, have been compared with this method.
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Affiliation(s)
- D H Kim
- Organic Analytical Laboratory, Korea Research Institute of Standards and Science
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9
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Terpstra AH. Comparison of the metabolism of [1,2,6,7-3H(N)]cholesteryl oleate, cholesteryl [9,10-3H]oleate, and cholesteryl [1-14C]oleate labeled lipoproteins in the rat. Atherosclerosis 1994; 106:203-11. [PMID: 8060380 DOI: 10.1016/0021-9150(94)90125-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The intravascular metabolism of sterol labeled [1,2,6,7-3H(N)]cholesteryl oleate and acyl labeled cholesteryl [9,10-3H]oleate and cholesteryl [1-14C]oleate was compared in the rat, an animal species without plasma cholesteryl ester transfer activity (CETA). In a first series of studies, the metabolism of sterol labeled [1,2,6,7-3H(N)]cholesteryl oleate and acyl labeled cholesteryl [1-14C]oleate was compared, and the two tracers had identical plasma clearance rates when incorporated into human low density lipoproteins (LDL). The 3H sterol labeled cholesteryl ester (CE), however, had a plasma clearance rate lower than the 14C acyl labeled CE when incorporated into rat alpha- and beta-migrating LDL and human or rat high density lipoproteins (HDL). Unesterified 3H cholesterol reappeared in the plasma whereas the 14C radioactivity in the plasma remained associated with the CE. In a second set of studies, LDL and HDL were radiolabeled with cholesteryl [9,10-3H]oleate and cholesteryl [1-14C]oleate. Large amounts of 3H radioactivity that were dialyzable and not associated with the lipoprotein CE reappeared in the plasma during the kinetic studies. The two tracers had identical plasma disappearance rates when the plasma samples were dialyzed. The results of these studies indicate that the nature of the tracer used to trace lipoprotein CE can affect the estimated kinetic parameters of plasma CE.
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Affiliation(s)
- A H Terpstra
- Brown University Program-in-Medicine, Division of Nutrition and Metabolism, Miriam Hospital, Providence, RI 02906
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10
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Terpstra AH. Comparison of the intravascular metabolism of cholesteryl esters and apoproteins of plasma low- and high-density lipoproteins in the rat (Rattus norvegicus), an animal species without plasma cholesteryl ester transfer activity. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. B, COMPARATIVE BIOCHEMISTRY 1993; 106:837-843. [PMID: 8299346 DOI: 10.1016/0305-0491(93)90039-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
1. The intravascular metabolism of the cholesteryl esters (CE) and apoproteins of low density lipoproteins (LDL) and high density lipoproteins (HDL) was compared in the rat, an animal species without plasma cholesteryl ester transfer activity (CETA). 2. The apoproteins and the CE of LDL had identical catabolic rates, and there was no transfer of LDL CE to other lipoprotein classes. 3. The CE of the HDL, however, had higher catabolic rates than the apoproteins, and there was transfer of HDL CE to LDL but not to very low density lipoproteins.
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Affiliation(s)
- A H Terpstra
- Brown University Program-in-Medicine, Division of Nutrition and Metabolism, Miriam Hospital, Providence, RI 02906
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11
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Wolfe MS, Parks JS, Morgan TM, Rudel LL. Age and dietary polyunsaturated fat alter high density lipoprotein subfraction cholesterol concentrations in a pediatric population of African green monkeys. ARTERIOSCLEROSIS AND THROMBOSIS : A JOURNAL OF VASCULAR BIOLOGY 1991; 11:617-28. [PMID: 1903063 DOI: 10.1161/01.atv.11.3.617] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
African green monkeys were raised from birth to 60 months of age on diets containing cholesterol (0.8 mg/kcal) and enriched in polyunsaturated (polyunsaturated to saturated fat ratio [P:S] = 2.5) or saturated (P:S = 0.3) fat. Lipoproteins were isolated from plasma of a group of animals (N = 123) and were separated by gel filtration chromatography at 9, 14, 26, 38, and 50 months of age, which covered a period through adolescence into young adulthood. Total plasma cholesterol (TPC) concentrations were 16% lower (p = 0.01) in the polyunsaturated fat-fed group, and high density lipoprotein (HDL) cholesterol concentrations averaged 20% lower (p = 0.008) in this group between 14 and 50 months of age, while plasma apolipoprotein A-I (apo A-I) averaged 7% lower (p = 0.06) over this age interval in the animals. The HDL cholesterol to apo A-I ratio was found to be significantly lower (p = 0.006) in the animals fed the polyunsaturated fat diet. This suggested that the HDL subfraction distribution might differ between groups. In a subset of animals (n = 105, 64 male and 41 female), HDL was subfractionated by density gradient ultracentrifugation into six subfractions, HDL-I to HDL-VI, from lowest to highest density. The saturated fat-fed animals had significantly higher cholesterol concentrations in HDL-I and significantly lower cholesterol concentrations in HDL-III, HDL-IV, and HDL-V. These effects held across all ages studied; therefore, these diet effects were not age dependent. In both diet groups, the HDL subfraction pattern changed with age such that the HDL-I and HDL-II cholesterol concentrations decreased, and those of HDL-IV, HDL-V, and HDL-VI increased as the animals matured. The decrease in HDL-I with age appeared to result primarily from a decrease in HDL-I in males, while the HDL-I cholesterol concentration in females did not change with age. We conclude that diet, age, and gender all affect HDL subfraction distribution and therefore can potentially modify the relative atherogenicity of the plasma HDL populations. It remains for future studies to demonstrate the effectiveness of each subfraction in promoting or preventing the cholesterol deposition of atherosclerosis.
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Affiliation(s)
- M S Wolfe
- Department of Biochemistry, Bowman Gray School of Medicine, Wake Forest University, Winston-Salem, NC 27103
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12
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Magot T, Malmendier CL, Ouguerram K, Lontie JF, Lutton C. In vivo effect of simvastatin on lipoprotein cholesteryl ester metabolism in normocholesterolemic volunteers. Clin Chim Acta 1991; 196:59-68. [PMID: 2022059 DOI: 10.1016/0009-8981(91)90208-t] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
A kinetic study on lipoprotein cholesteryl ester metabolism was carried out in 4 normolipidemic volunteers before and after treatment with simvastatin. They received LDL labelled with 3H-cholesteryl linoleate. A lipoprotein cholesteryl ester model was developed that fit the radioactivity in LDL, HDL and VLDL cholesteryl ester during 24 hours following injection. Before treatment, the model is consistent with previously reported data. Moreover our results suggest that, in normal fasting subjects, the efflux of plasma cholesteryl ester is almost exclusively derived from LDL. Administration of drug decreased LDL cholesteryl ester concentration by 35%. After treatment, the rate constant concerning LDL catabolism was increased by 25% and the model required the existence of a direct removal of VLDL cholesteryl ester (40% of total VLDL turnover). Our results suggest that the reduction in the LDL cholesteryl ester concentration induced by treatment with simvastatin is due to an increase in the uptake of LDL and LDL precursors (VLDL, VLDL remnants) by LDL receptors.
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Affiliation(s)
- T Magot
- Laboratoire de Physiologie de la Nutrition, URA DO646 CNRS, Université de Paris-Sud, Orsay, France
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13
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Araki N, Horiuchi S, Rahim AT, Takata K, Morino Y. Microquantification of cholesterol and cholesteryl esters in rat peritoneal macrophages by reverse-phase high-performance liquid chromatography. Anal Biochem 1990; 185:339-45. [PMID: 2339790 DOI: 10.1016/0003-2697(90)90305-s] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
A simple and rapid method for the microquantification of cholesterol and cholesteryl esters by reverse-phase high performance liquid chromatography has been established. Comparison of elution patterns of authentic cholesterol and cholesteryl esters revealed that a mu Bondasphere reverse-phase C8 (300-A) column was more suitable than a corresponding reverse-phase C4 or C18 column in terms of rapidity and sensitivity. Recovery of cholesterol and cholesteryl esters from a C8 column was greater than 98% when determined either by radioactive cholesterol and cholesteryl oleate or by cholesteryl heptadecanoate. The sensitivity of the quantification ranged from 5 ng to 50 micrograms for both cholesterol and cholesteryl esters. This method was applied to determination of cellular cholesterol and cholesteryl esters of rat peritoneal macrophages. Lipid extracts of these cells were found to contain 38.01 +/- 2.60 micrograms of cholesterol and 3.18 +/- 0.36 micrograms of cholesteryl esters per milligram of cell protein. When the cells were loaded with cholesteryl esters by incubation for 24 h with various concentrations of acetylated low-density lipoprotein, a cellular level of cholesteryl esters showed a dose-dependent increase and reached a maximal level of 106.60 +/- 3.05 micrograms/mg cell protein. Thus, the present method is useful for the microquantification of cholesterol and cholesteryl esters from lipid extracts of biological samples.
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Affiliation(s)
- N Araki
- Department of Biochemistry, Kumamoto University Medical School, Japan
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14
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Sorci-Thomas M, Babiak J, Rudel LL. Lecithin-cholesterol acyltransferase (LCAT) catalyzes transacylation of intact cholesteryl esters. Evidence for the partial reversal of the forward LCAT reaction. J Biol Chem 1990. [DOI: 10.1016/s0021-9258(19)39852-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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15
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Ettinger WH, Dysko RC, Clarkson TB. Prednisone increases low density lipoprotein in cynomolgus monkeys fed saturated fat and cholesterol. ARTERIOSCLEROSIS (DALLAS, TEX.) 1989; 9:848-55. [PMID: 2590064 DOI: 10.1161/01.atv.9.6.848] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Cynomolgus monkeys were given prednisone to determine its effects on lipoprotein metabolism and other risk factors for atherosclerotic cardiovascular disease. After 1 month of oral prednisone, the mean total plasma cholesterol (TPC) concentration increased from 240 +/- 36 to 476 +/- 78 mg/dl (p less than 0.01) in animals fed a diet containing 36% of calories as fat (polyunsaturated/monounsaturated/saturated, 1.0:3.9:4.1) and cholesterol (0.39 mg/kcal). The increase in TPC was due to higher concentrations of the apolipoprotein B (apo B)-containing lipoproteins, particularly low density lipoprotein (LDL). LDL cholesterol concentrations also increased in animals fed a diet containing saturated fat and 0.25 mg/kcal of cholesterol, as well as in animals fed monkey chow. Kinetic studies of LDL indicated both an increased flux of apo B into LDL and a decrease in the fractional catabolic rate of LDL. Mean high density lipoprotein cholesterol (HDL-C) concentration decreased from 48 +/- 8.2 to 14 +/- 4 mg/dl, p less than 0.001, in animals fed fat and cholesterol, but there was no significant change in HDL-C in animals fed monkey chow. Blood pressure, fasting serum glucose, and anthropometric measures did not change after 7 months of prednisone therapy. Prednisone increases LDL concentration in the cynomolgus monkey. This animal may be a good model for studying corticosteroid dyslipoproteinemia, and possibly atherosclerosis, in an immunosuppressed host.
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Affiliation(s)
- W H Ettinger
- Department of Internal Medicine, Bowman Gray School of Medicine, Wake Forest University, Winston-Salem, North Carolina
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Vercaemst R, Union A, Rosseneu M, De Craene I, De Backer G, Kornitzer M. Quantitation of plasma free cholesterol and cholesteryl esters by high performance liquid chromatography. Study of a normal population. Atherosclerosis 1989; 78:245-50. [PMID: 2783206 DOI: 10.1016/0021-9150(89)90230-x] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
We describe a convenient method for the separation and quantitation of plasma free cholesterol and cholesteryl esters by high performance liquid chromatography (HPLC). After extraction of 100 microliters plasma with isopropanol the plasma cholesteryl esters were resolved on a Zorbax ODS reversed-phase column by isocratic elution with acetonitrile/isopropanol (50:50, v/v). Baseline separation of the plasma cholesteryl esters including the internal standard was obtained within a 25-min run. The intra- and interassay CV was less than 4%. The results obtained by HPLC show good agreement with enzymatic and gas-liquid chromatographic methods. High performance liquid chromatography provides a simple method for the quantitation of individual cholesteryl esters avoiding tedious chromatographic and derivatisation steps inherent to GLC. Our HPLC method was applied to the monitoring of plasma cholesteryl esters in a normal population and can also be used for the study of cholesteryl esters from lipid extracts of biological samples.
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Affiliation(s)
- R Vercaemst
- Department of Clinical Chemistry, A.Z. St-Jan, Bruges, Belgium
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