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Lei D, Yu Y, Kuang YL, Liu J, Krauss RM, Ren G. Single-molecule 3D imaging of human plasma intermediate-density lipoproteins reveals a polyhedral structure. Biochim Biophys Acta Mol Cell Biol Lipids 2018; 1864:260-270. [PMID: 30557627 PMCID: PMC6409128 DOI: 10.1016/j.bbalip.2018.12.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Revised: 11/25/2018] [Accepted: 12/09/2018] [Indexed: 11/25/2022]
Abstract
Intermediate-density lipoproteins (IDLs), the remnants of very-low-density lipoproteins via lipolysis, are rich in cholesteryl ester and are associated with cardiovascular disease. Despite pharmacological interest in IDLs, their three-dimensional (3D) structure is still undetermined due to their variation in size, composition, and dynamic structure. To explore the 3D structure of IDLs, we reconstructed 3D density maps from individual IDL particles using cryo-electron microscopy (cryo-EM) and individual-particle electron tomography (IPET, without averaging from different molecules). 3D reconstructions of IDLs revealed an unexpected polyhedral structure that deviates from the generally assumed spherical shape model (Frias et al., 2007; Olson, 1998; Shen et al., 1977). The polyhedral-shaped IDL contains a high-density shell formed by flat surfaces that are similar to those of very-low-density lipoproteins but have sharper dihedral angles between nearby surfaces. These flat surfaces would be less hydrophobic than the curved surface of mature spherical high-density lipoprotein (HDL), leading to a lower binding affinity of IDL to hydrophobic proteins (such as cholesteryl ester transfer protein) than HDL. This is the first visualization of the IDL 3D structure, which could provide fundamental clues for delineating the role of IDL in lipid metabolism and cardiovascular disease.
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Affiliation(s)
- Dongsheng Lei
- The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Yadong Yu
- The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Yu-Lin Kuang
- Atherosclerosis Research, Children's Hospital Oakland Research Institute, Oakland, CA 94609, USA
| | - Jianfang Liu
- The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Ronald M Krauss
- Atherosclerosis Research, Children's Hospital Oakland Research Institute, Oakland, CA 94609, USA
| | - Gang Ren
- The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
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Nakajima K, Tokita Y, Tanaka A. Hypothesis: Postprandial remnant lipoproteins are the causal factors that induce the insulin resistance associated with obesity. Clin Chim Acta 2018; 485:126-132. [PMID: 29958888 DOI: 10.1016/j.cca.2018.06.029] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2018] [Revised: 06/16/2018] [Accepted: 06/21/2018] [Indexed: 11/17/2022]
Abstract
We have long thought that remnant lipoproteins (RLP) in plasma are significantly increased as the result of disturbed lipoprotein metabolism followed by obesity and insulin resistance. Therefore, it was believed that insulin resistance causes and enhances RLP formation. In contrast, this hypothesis states that RLP induces insulin resistance as the result of obesity associated with the excessive fat intake. The majority of plasma TG increased after fat intake is TG in RLP (RLP-TG) and the majority of postprandial RLP is VLDL remnants, not CM remnants. RLP is newly formed lipoproteins primarily for energy supply against starvation, like blood sugar after carbohydrate intake. Since RLP bearing apoE, LPL and Lp(a) function as ligands for the VLDL receptor, RLP interacts with the VLDL receptor in visceral fat adipocytes and stored as TG similar to excessive blood sugar. However, the excessive VLDL remnants induces obesity and its associated insulin resistance, which plays a major role as the initiator of metabolic domino effects, similar to blood sugar primarily serving as an energy supply to protect against starvation.
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Affiliation(s)
- Katsuyuki Nakajima
- Laboratory of Clinical Nutrition and Medicine, Kagawa Nutrition University, Tokyo, Japan.
| | - Yoshiharu Tokita
- Laboratory of Clinical Nutrition and Medicine, Kagawa Nutrition University, Tokyo, Japan; Graduate School of Health Sciences, Gunma University, Maebashi, Gunma, Japan
| | - Akira Tanaka
- Laboratory of Clinical Nutrition and Medicine, Kagawa Nutrition University, Tokyo, Japan
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Nakajima K, Tanaka A. Postprandial remnant lipoproteins as targets for the prevention of atherosclerosis. Curr Opin Endocrinol Diabetes Obes 2018; 25:108-117. [PMID: 29493553 DOI: 10.1097/med.0000000000000393] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
PURPOSE OF REVIEW Oxidized low-density lipoprotein (Ox-LDL) and chylomicron remnants were previously proposed as the most atherogenic lipoproteins for the causal lipoproteins of atherosclerosis. However, there are still controversies on these hypothesizes. Therefore, we have proposed a new hypothesis based on our recent findings of remnant lipoproteins (RLPs) in postprandial plasma. RECENT FINDINGS Plasma RLP-C and RLP-TG increased significantly after fat load. More than 80% of the increased triglycerides after fat load consisted of the triglycerides in RLP, which contained greater amount of apoB100 than apoB48 particles as mostly very low density lipoproteins (VLDL) remnants. The majority of lipoprotein lipase (LPL) in plasma was found in RLP as RLP-LPL complex, which is released into circulation after hydrolysis. LPL activity and concentration in plasma did not increase after food intake associated with the insufficient hydrolysis of chylomicrons and VLDL and resulted in the significant increase of RLP-TG. Plasma LPL was inversely correlated with RLP particle size and number. SUMMARY VLDL remnants have been shown as the major atherogenic lipoproteins in postprandial plasma associated with LPL activity as the targets for prevention of atherosclerosis. We also proposed a new definition of RLPs, 'LPL bound TG-rich lipoproteins' based on the findings of RLP-LPL complex.
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Affiliation(s)
- Katsuyuki Nakajima
- Laboratory of Clinical Nutrition and Medicine, Kagawa Nutrition University, Tokyo
- Department of Clinical Laboratory Medicine, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Akira Tanaka
- Laboratory of Clinical Nutrition and Medicine, Kagawa Nutrition University, Tokyo
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Nakajima K, Tanaka A. Atherogenic postprandial remnant lipoproteins; VLDL remnants as a causal factor in atherosclerosis. Clin Chim Acta 2018; 478:200-215. [PMID: 29307667 DOI: 10.1016/j.cca.2017.12.039] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2017] [Revised: 12/23/2017] [Accepted: 12/24/2017] [Indexed: 01/02/2023]
Abstract
Oxidized LDL (Ox-LDL) and chylomicron (CM) remnants have been suggested to be the most atherogenic lipoproteins that initiate and exacerbate coronary atherosclerosis. In this review, we propose a hypothesis of the causal lipoproteins in atherosclerosis based on our recent findings on postprandial remnant lipoproteins (RLP). Plasma RLP-C and RLP-TG increased significantly after food intake, especially a fat load. More than 80% of the TG increase after the fat load consisted of the TG in RLP, which contained significantly greater apoB100 than apoB48 particles as VLDL remnants. The majority of the LPL in non-heparin plasma was found in RLP as an RLP-LPL complex and released into the circulation after hydrolysis. Plasma LPL did not increase after food intake, which may have caused the partial hydrolysis of CM and VLDL as well as the significant increase of RLP-TG in the postprandial plasma. LPL was inversely correlated with the RLP particle size after food intake. We showed that VLDL remnants are the major atherogenic lipoproteins in the postprandial plasma associated with insufficient LPL activity and a causal factor in the initiation and progression of atherosclerosis. We also propose "LPL bound TG-rich lipoproteins" as a new definition of remnant lipoproteins based on the findings of the RLP-LPL complex in the non-heparin plasma.
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Affiliation(s)
- Katsuyuki Nakajima
- Laboratory of Clinical Nutrition and Medicine, Kagawa Nutrition University, Tokyo, Japan; Department of Clinical Laboratory Medicine, Gunma University Graduate School of Medicine, Maebashi, Japan.
| | - Akira Tanaka
- Laboratory of Clinical Nutrition and Medicine, Kagawa Nutrition University, Tokyo, Japan
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Bagdade JD, Lane JT, Subbaiah PV. Probucol normalizes cholesteryl ester transfer in type 2 diabetes. Diabetes Res Clin Pract 2016; 116:29-35. [PMID: 27321313 DOI: 10.1016/j.diabres.2016.04.020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/26/2015] [Revised: 03/02/2016] [Accepted: 04/16/2016] [Indexed: 11/18/2022]
Abstract
AIMS Accelerated cholesteryl ester transfer (CET) protein (CETP) activity is believed to promote macrovascular disease in patients with type 2 diabetes (T2D) by increasing the cholesterol burden of the apoB - containing triglyceride-rich lipoprotein (TGRLP) CE acceptors and promoting small dense LDL formation. While previous studies have shown that this same abnormality is present in patients with type 1 diabetes (T1D) and was normalized by the anti-oxidant drug probucol, its effects on CET in T2D are unknown. PATIENTS AND METHODS The net mass transfer of CE from HDL to the apoB lipoproteins (VLDL+LDL) was studied in intact plasma from seven T2D patients before and two months after treatment with probucol (1g/day). RESULTS Before treatment, CET was significantly greater than controls at 1 and 2h (p<.005). Recombination studies showed that this disturbance was attributable to dysfunction of VLDL and not due to altered behavior of HDL or CETP. Probucol treatment normalized CET in all subjects and significantly lowered plasma cholesterol (pre-Rx: 197±4.5 vs post-Rx: 162±27.1mg/dL; mean±S.D.; p<.025) and HDL-C (pre-Rx: 46.4±7.5 vs post-Rx: 39.1±4.0; p<.025) without changing glycemic control. CONCLUSIONS By normalizing CET in T2D, probucol likely reduces the formation of atherogenic lipoproteins. This effect on CET is achieved through qualitative alterations in CETP's lipoprotein substrates and not through changes in CETP or HDL. Since probucol also has potent anti-oxidative and anti-inflammatory properties, it may have a new role to play in lipoprotein remodeling that reduce cardiovascular risk in T2D.
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Affiliation(s)
- John D Bagdade
- Rush University Medical Center, 1725 West Harrison, Chicago, IL 60612, United States.
| | - James T Lane
- Oklahoma University Health Sciences Center, Oklahoma City, OK, United States
| | - P V Subbaiah
- Department of Medicine, University of Illinois at Chicago College of Medicine, 909 S. Wolcott, Chicago, IL 60612, United States; Department of Biochemistry, University of Illinois at Chicago College of Medicine, 909 S. Wolcott, Chicago, IL 60612, United States
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Yatsuzuka SI, Shimomura Y, Akuzawa M, Ando Y, Kobayashi I, Nakano T, Tokita Y, Nagamine T, Ono H, Tanaka A, Schaefer E, Nakajima K. Plasma adiponectin is a more specific marker of fatty liver than a marker of metabolic syndrome in Japanese men. Ann Clin Biochem 2013; 51:68-79. [PMID: 23897104 DOI: 10.1177/0004563213487892] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
BACKGROUND The association of plasma cardiovascular risk markers and metabolic syndrome (MetS) with non-alcoholic fatty liver disease (NAFLD) has not been well defined. METHODS Japanese men (n = 809) had standard anthropometric measurements done, and had their liver fat quantitated by ultrasound. Three groups were identified: (1) normal controls without significant disease, (2) preliminary-metabolic syndrome (pre-MetS) cases and (3) MetS cases. Plasma adiponectin, high sensitivity-C reactive protein (hs-CRP), HOMA-IR, lipids, lipoproteins and liver enzymes were evaluated among the three groups. RESULTS The prevalence of fatty liver was 13% in controls, 39% in pre-MetS and 62% in MetS. Plasma adiponectin and high density lipoprotein cholesterol (HDL-C) were significantly decreased, and HOMA-IR, hs-CRP, TG, remnant lipoproteins (RLPs) and small dense-LDL-C (sd LDL-C) were significantly increased in subjects with fatty liver compared to those without fatty liver. Multivariate analyses of serum parameters associated with fatty liver revealed that adiponectin and hs-CRP were more strongly associated with the presence of fatty liver than waist circumference. However, HOMA-IR, HDL-C, TG, RLP-C, RLP-TG and sd LDL-C were more strongly associated with waist circumference than with fatty liver. Factor analysis revealed that adiponectin and HDL-C were linked to liver enzymes, lipoproteins and HOMA-IR associated with fatty liver, but not with waist circumference. CONCLUSIONS Adiponectin was found to be a more specific diagnostic marker for the presence of fatty liver regardless of MetS status, and was inversely correlated with liver enzyme concentrations. However, RLPs were found to be more specifically associated with the presence of MetS.
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Affiliation(s)
- Shin-Ichi Yatsuzuka
- Diabetes and Metabolic Disease Research Center, Hidaka Hospital, Takasaki, Japan
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Nakajima K, Nakano T, Tokita Y, Nagamine T, Yatsuzuka SI, Shimomura Y, Tanaka A, Sumino H, Nara M, Machida T, Murakami M. The characteristics of remnant lipoproteins in the fasting and postprandial plasma. Clin Chim Acta 2012; 413:1077-86. [DOI: 10.1016/j.cca.2012.02.026] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2012] [Revised: 02/18/2012] [Accepted: 02/23/2012] [Indexed: 11/16/2022]
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Rhainds D, Arsenault BJ, Brodeur MR, Tardif JC. An update on the clinical development of dalcetrapib (RO4607381), a cholesteryl ester transfer protein modulator that increases HDL cholesterol levels. Future Cardiol 2012; 8:513-31. [DOI: 10.2217/fca.12.25] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
CETP is the target of CETP inhibitors such as anacetrapib and the modulator dalcetrapib. Both molecules have entered Phase III clinical trials, with the ultimate goal of reducing cardiovascular events by raising HDL cholesterol. At the 600-mg dose selected for the dal-OUTCOMES study, dalcetrapib is expected to inhibit CETP activity by approximately 30% and raise HDL-C by approximately 30% with limited effects on LDL cholesterol. Importantly, dalcetrapib does not raise blood pressure or aldosterone levels, two effects previously associated with the CETP inhibitor torcetrapib. Dalcetrapib has been well tolerated at the 600-mg dose. In the dal-PLAQUE atherosclerosis imaging study, dalcetrapib reduced the enlargement of total vessel area over time. In May 2012, following the results of the second interim analysis of dal-OUTCOMES, the Data and Safety Monitoring Board recommended stopping the study owing to a lack of clinically significant benefit, which was followed by Roche’s (Basel, Switzerland) decision to terminate the study and the dalcetrapib program (dal-HEART). Contrary to anacetrapib, a potent CETP inhibitor that markedly increases HDL cholesterol and significantly reduces LDL cholesterol, dalcetrapib has allowed us to test the hypothesis that an isolated, moderate elevation in HDL cholesterol prevents cardiovascular events.
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Affiliation(s)
- David Rhainds
- Atherosclerosis Research Group, Montreal Heart Institute, 5000 Belanger St., Montreal, Quebec, H1T 1C8, Canada
| | - Benoit J Arsenault
- Atherosclerosis Research Group, Montreal Heart Institute, 5000 Belanger St., Montreal, Quebec, H1T 1C8, Canada
| | - Mathieu R Brodeur
- Atherosclerosis Research Group, Montreal Heart Institute, 5000 Belanger St., Montreal, Quebec, H1T 1C8, Canada
| | - Jean-Claude Tardif
- Atherosclerosis Research Group, Montreal Heart Institute, 5000 Belanger St., Montreal, Quebec, H1T 1C8, Canada
- Faculty of Medicine, Université de Montréal, 2900, Boulevard Édouard-Montpetit Montréal, Québec H3T 1J4, Canada
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Hooper AJ, Burnett JR. Dalcetrapib , a cholesteryl ester transfer protein modulator. Expert Opin Investig Drugs 2012; 21:1427-32. [PMID: 22725099 DOI: 10.1517/13543784.2012.699040] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION Cholesteryl ester transfer protein (CETP) plays an important role in reverse cholesterol transport by transferring cholesteryl esters from high-density lipoprotein (HDL) to the apolipoprotein B-containing lipoproteins. Inhibition of CETP is a target to increase HDL-cholesterol and potentially reduce atherosclerosis. Dalcetrapib is an orally administered CETP inhibitor developed for the treatment of primary hypercholesterolaemia and mixed hyperlipidaemia. AREAS COVERED AREAS COVERED are: mode of action, preclinical development and clinical trials of dalcetrapib, a CETP modulator. The article provides an understanding of the pharmacokinetic and pharmacodynamic characteristics of dalcetrapib and insight into its clinical efficacy and safety. In clinical trials, dalcetrapib produced significant elevations in HDL-cholesterol when taken alone or in combination with statin with no effect on blood pressure or expression of genes involved in the renin-angiotensin-aldosterone system. EXPERT OPINION Although dalcetrapib is the least potent CETP inhibitor, it does not impair the formation of CETP-induced pre-β HDL, which might be needed to increase reverse cholesterol transport. While dalcetrapib is well-tolerated and does not show major side effects, the recent interim results of the Phase III dal-OUTCOMES trial have shown the lack of a clinically meaningful benefit, and further testing of the drug has been halted.
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Affiliation(s)
- Amanda J Hooper
- Royal Perth Hospital, Department of Core Clinical Pathology & Biochemistry, PathWest Laboratory Medicine WA, Perth, Western Australia
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Lei YF, Chen JL, Wei H, Xiong CM, Zhang YH, Ruan JL. Hypolipidemic and anti-inflammatory properties of Abacopterin A from Abacopteris penangiana in high-fat diet-induced hyperlipidemia mice. Food Chem Toxicol 2011; 49:3206-10. [DOI: 10.1016/j.fct.2011.08.027] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2011] [Revised: 08/26/2011] [Accepted: 08/28/2011] [Indexed: 12/21/2022]
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Nakajima K, Nakano T, Tokita Y, Nagamine T, Inazu A, Kobayashi J, Mabuchi H, Stanhope KL, Havel PJ, Okazaki M, Ai M, Tanaka A. Postprandial lipoprotein metabolism: VLDL vs chylomicrons. Clin Chim Acta 2011; 412:1306-18. [PMID: 21531214 PMCID: PMC3265327 DOI: 10.1016/j.cca.2011.04.018] [Citation(s) in RCA: 108] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2011] [Revised: 04/11/2011] [Accepted: 04/12/2011] [Indexed: 12/31/2022]
Abstract
Since Zilversmit first proposed postprandial lipemia as the most common risk of cardiovascular disease, chylomicrons (CM) and CM remnants have been thought to be the major lipoproteins which are increased in the postprandial hyperlipidemia. However, it has been shown over the last two decades that the major increase in the postprandial lipoproteins after food intake occurs in the very low density lipoprotein (VLDL) remnants (apoB-100 particles), not CM or CM remnants (apoB-48 particles). This finding was obtained using the following three analytical methods; isolation of remnant-like lipoprotein particles (RLP) with specific antibodies, separation and detection of lipoprotein subclasses by gel permeation HPLC and determination of apoB-48 in fractionated lipoproteins by a specific ELISA. The amount of the apoB-48 particles in the postprandial RLP is significantly less than the apoB-100 particles, and the particle sizes of apoB-48 and apoB-100 in RLP are very similar when analyzed by HPLC. Moreover, CM or CM remnants having a large amount of TG were not found in the postprandial RLP. Therefore, the major portion of the TG which is increased in the postprandial state is composed of VLDL remnants, which have been recognized as a significant risk for cardiovascular disease.
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Affiliation(s)
- Katsuyuki Nakajima
- School of Health Sciences, Faculty of Medicine, Gunma University, Maebashi, Gunma, Japan.
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Lei Y, Chen J, Cai Y, Xiong C, Ruan J. Hypolipidemic potential of Lepidogrammitis drymoglossoides in high-fat diet fed mice. Int J Cardiol 2011; 147:323-5. [DOI: 10.1016/j.ijcard.2010.12.077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2010] [Accepted: 12/21/2010] [Indexed: 10/18/2022]
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Nakano T, Tokita Y, Nagamine T, Tanaka A, Okazaki M, Yatsuzuka S, Tamei N, Shimomura Y, Ando Y, Akamatsu S, Fujita MQ, Nakajima K. Measurement of serum remnant-like lipoprotein particle-triglyceride (RLP-TG) and RLP-TG/total TG ratio using highly sensitive triglyceride assay reagent. Clin Chim Acta 2011; 412:71-8. [DOI: 10.1016/j.cca.2010.09.040] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2010] [Revised: 09/10/2010] [Accepted: 09/10/2010] [Indexed: 10/18/2022]
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Docking and molecular dynamics study on the inhibitory activity of N, N-disubstituted-trifluoro-3-amino-2-propanols-based inhibitors of cholesteryl ester transfer protein. J Mol Model 2010; 17:1727-34. [DOI: 10.1007/s00894-010-0881-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2010] [Accepted: 10/18/2010] [Indexed: 11/25/2022]
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Ma KY, Yang N, Jiao R, Peng C, Guan L, Huang Y, Chen ZY. Dietary calcium decreases plasma cholesterol by down-regulation of intestinal Niemann-Pick C1 like 1 and microsomal triacylglycerol transport protein and up-regulation of CYP7A1 and ABCG 5/8 in hamsters. Mol Nutr Food Res 2010; 55:247-58. [PMID: 20715096 DOI: 10.1002/mnfr.201000161] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2010] [Revised: 06/16/2010] [Accepted: 06/19/2010] [Indexed: 11/09/2022]
Abstract
SCOPE It has been shown that calcium supplementation favorably modifies plasma lipoprotein profile in postmenopausal women. The present study investigated the interaction of dietary calcium with genes of transporters, receptors and enzymes involved in cholesterol metabolism. METHODS AND RESULTS Forty-eight ovariectomized hamsters were fed one of the four diets containing 0, 2, 6 and 8 g calcium per kg. Plasma total cholesterol (TC), triacylglycerols (TG), and non-high density lipoprotein cholesterol were dose-dependently decreased, whereas high-density lipoprotein cholesterol (HDL-C) was dose-dependently increased with the increasing dietary calcium levels. Dietary calcium had no effect on protein mass of hepatic sterol regulatory element binding protein-2 (SREBP), liver X receptor-alpha (LXR), 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR), LDL receptor (LDLR) and cholesterol-7α-hydroxylase (CYP7A1). However, dietary calcium up-regulated the mRNA levels of hepatic CYP7A1 and intestinal ATP binding cassette transporters (ABCG5/8) whereas it down-regulated the intestinal Niemann-Pick C1 like 1 (NPC1L1) and microsomal triacylglycerol transport protein (MTP). In addition, dietary calcium increased the activity of intestinal acyl coenzyme A: cholesterol acyltransferase 2, while it decreased plasma cholesteryl ester transport protein (CETP). CONCLUSION Beneficial modification of lipoprotein profile by dietary calcium was mediated by sequestering bile acid absorption and enhancing excretion of fecal cholesterol, via up-regulation of mRNA CYP7A1 and intestinal ABCG 5/8 with down-regulation of mRNA NPC1L1 and MTP.
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Affiliation(s)
- Ka Ying Ma
- Food & Nutritional Sciences Programme of Department of Biochemistry, The Chinese University of Hong Kong, Shatin, NT, Hong Kong, PR China
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Abstract
IMPORTANCE OF THE FIELD While statins reduce the risk of cardiovascular disease by up to 50%, many patients remain at increased risk due to low levels of high-density lipoprotein cholesterol (HDL-C). Whether pharmacologically raising HDL-C per se with drug therapy will reduce cardiovascular events remains to be determined. AREAS COVERED IN THIS REVIEW Review of HDL-C-raising compounds, with a focus on cholesteryl ester transfer protein (CETP) inhibitors. WHAT THE READER WILL GAIN An overview of the CETP inhibitor dalcetrapib. Despite 70% increases in HDL-C, development of the CETP inhibitor torcetrapib was halted due to excess mortality, attributed largely to activation of the renin-angiotensin-aldosterone system resulting in hypertensive effects. Development of the CETP inhibitors dalcetrapib and anacetrapib is ongoing. Dalcetrapib has a unique chemical structure and induces a conformational change in CETP rather than forming a non-productive CETP/HDL-C complex as do the other CETP inhibitors. Although dalcetrapib is the least potent CETP inhibitor of the three in terms of CETP activity, the 900-mg dose did not increase blood pressure or raise aldosterone levels over 48 weeks of follow-up. The 600-mg dose of dalcetrapib is moving forward and raises HDL-C by 25 - 30% when used alone or in combination with a statin, with little effect on low-density lipoprotein cholesterol levels. TAKE HOME MESSAGE Before regulatory approval is granted, results from the ongoing dal-OUTCOMES trial evaluating the effects of dalcetrapib 600 mg daily over standard statin therapy on mortality and morbidity in > 15,000 high-risk CHD patients will be needed. The Dalcetrapib HDL Evaluation, Atherosclerosis and Reverse Cholesterol Transport (dal-HEART) program also includes three surrogate end point trials, dal-VESSEL, dal-PLAQUE and dal-PLAQUE 2, which will provide further information as to the contribution of CETP to cardiovascular disease.
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Ai M, Tanaka A, Shimokado K, Ohtani R, Inazu A, Kobayashi J, Mabuchi H, Nakano T, Nakajima K. A deficiency of cholesteryl ester transfer protein whose serum remnant-like particle-triglyceride significantly increased, but serum remnant-like particle-cholesterol did not after an oral fat load. Ann Clin Biochem 2009; 46:457-63. [DOI: 10.1258/acb.2009.008249] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Background We found a unique cholesteryl ester transfer protein (CETP) deficient case with markedly elevated serum triglyceride (TG) as well as high-density lipoprotein cholesterol (HDL-C) levels. Most of the CETP deficiency cases were reported to have normal or reduced serum TG with elevated HDL-C. Methods The case subject was a 40-year-old male with a compound heterozygous CETP deficiency. Two heterozygous CETP deficient cases and 10 normal volunteers were also recruited as controls. They underwent an oral fat tolerance test (OFTT) and their blood was taken at fasting and during the OFTT to be used for laboratory tests. Results The case subject had apolipoprotein E (apo-E) phenotype 4/2 with fatty liver but without any cardiovascular disease. His serum TG, HDL-C, apo-AI and apo-B48 levels were significantly higher, but the low-density lipoprotein cholesterol level was lower than controls. Although post-heparin plasma lipoprotein lipase and hepatic lipase (both mass and activity) were nearly normal, the serum level of angiopoietin-like-protein-3 was extremely elevated. While his serum remnant-like particles-TG (RLP-TG) and total TG levels significantly increased after a fat load, the RLP-cholesterol (RLP-C) level did not increase during OFTT. Conclusions The case subject was different from the common CETP deficient cases reported previously. Also, the results indicated that the metabolic pathways of RLP-C and RLP-TG formation in the postprandial state are controlled independently in CETP deficient cases. CETP deficiency itself may not be atherogenic, while one with elevated RLPs may be atherogenic. These cases may have raised the controversy of whether CETP deficiency is atherogenic or not.
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Affiliation(s)
- Masumi Ai
- Life Science and Bioethics Research Center
- Department of Vascular Medicine and Geriatrics, Tokyo Medical and Dental University
| | - Akira Tanaka
- Department of Vascular Medicine and Geriatrics, Tokyo Medical and Dental University
- Nutrition Clinic, Kagawa Nutrition University, Tokyo
| | - Kentaro Shimokado
- Department of Vascular Medicine and Geriatrics, Tokyo Medical and Dental University
| | - Rumiko Ohtani
- Department of Laboratory Sciences, School of Health Sciences
| | - Akihiro Inazu
- Department of Laboratory Sciences, School of Health Sciences
| | - Junji Kobayashi
- Department of Lipidology, Graduate School of Medical Science, Kanazawa University, Kanazawa
| | - Hiroshi Mabuchi
- Department of Lipidology, Graduate School of Medical Science, Kanazawa University, Kanazawa
| | - Takamitsu Nakano
- Diagnostic Division, Otsuka Pharmaceutical Co., Ltd, Tokyo, Japan
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Probucol markedly reduces HDL phospholipids and elevated preβ1-HDL without delayed conversion into α-migrating HDL: Putative role of angiopoietin-like protein 3 in probucol-induced HDL remodeling. Atherosclerosis 2008; 200:329-35. [DOI: 10.1016/j.atherosclerosis.2007.12.031] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2007] [Accepted: 12/27/2007] [Indexed: 11/21/2022]
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