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Deguchi H, Wolfbauer G, Cheung MC, Banerjee Y, Elias DJ, Fernández JA, Albers JJ, Griffin JH. Inhibition of thrombin generation in human plasma by phospholipid transfer protein. Thromb J 2015; 13:24. [PMID: 26185485 PMCID: PMC4504036 DOI: 10.1186/s12959-015-0054-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Accepted: 05/20/2015] [Indexed: 01/10/2023] Open
Abstract
Background Plasma phospholipid transfer protein (PLTP) transfers lipids between donors and acceptors (e.g., from HDL to VLDL) and modulates lipoprotein composition, size, and levels. No study has reported an assessment of the effects of PLTP on blood clotting reactions, such as reflected in thrombin generation assays, or on the association of venous thrombosis (VTE) risk with PLTP activity. Methods The in vitro effects of PLTP on blood coagulation reactions and the correlations between plasma PLTP activity levels and VTE were studied. Results Recombinant (r) PLTP concentration-dependently inhibited plasma thrombin generation and factor XII-dependent kallikrein generation when sulfatide was used to stimulate factor XII autoactivation in plasma. However, rPLTP did not inhibit thrombin generation in plasma induced by factor XIa or tissue factor, implicating an effect of PLTP on contact activation reactions. In purified systems, rPLTP inhibited factor XII autoactivation stimulated by sulfatide in the presence of VLDL. In surface plasmon resonance studies, purified factor XII bound to immobilized rPLTP, implying that rPLTP inhibits factor XII-dependent contact activation by binding factor XII in the presence of lipoproteins. Analysis of plasmas from 40 male patients with unprovoked VTE and 40 matched controls indicated that low PLTP lipid transfer activity (≤25th percentile) was associated with an increased risk of VTE after adjustment for body mass index, plasma lipids, and two known thrombophilic genetic risk factors. Conclusion These data imply that PLTP may be an antithrombotic plasma protein by inhibiting generation of prothrombotic factor XIIa in the presence of VLDL. This newly discovered anticoagulant activity of PLTP merits further clinical and biochemical studies. Electronic supplementary material The online version of this article (doi:10.1186/s12959-015-0054-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Hiroshi Deguchi
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, MEM180, 10550 North Torrey Pines Rd., La Jolla, CA 92037 USA
| | - Gertrud Wolfbauer
- Division of Metabolism, Endocrinology, and Nutrition, Northwest Lipid Metabolism and Diabetes Research Laboratories, Department of Medicine, University of Washington, Seattle, WA 98109 USA
| | - Marian C Cheung
- Division of Metabolism, Endocrinology, and Nutrition, Northwest Lipid Metabolism and Diabetes Research Laboratories, Department of Medicine, University of Washington, Seattle, WA 98109 USA
| | - Yajnavalka Banerjee
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, MEM180, 10550 North Torrey Pines Rd., La Jolla, CA 92037 USA ; Current Address: Department of Biochemistry, College of Medicine and Health Sciences, SQ University, Muscat, Oman
| | - Darlene J Elias
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, MEM180, 10550 North Torrey Pines Rd., La Jolla, CA 92037 USA
| | - José A Fernández
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, MEM180, 10550 North Torrey Pines Rd., La Jolla, CA 92037 USA
| | - John J Albers
- Division of Metabolism, Endocrinology, and Nutrition, Northwest Lipid Metabolism and Diabetes Research Laboratories, Department of Medicine, University of Washington, Seattle, WA 98109 USA
| | - John H Griffin
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, MEM180, 10550 North Torrey Pines Rd., La Jolla, CA 92037 USA
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Miller NE, Olszewski WL, Hattori H, Miller IP, Kujiraoka T, Oka T, Iwasaki T, Nanjee MN. Lipoprotein remodeling generates lipid-poor apolipoprotein A-I particles in human interstitial fluid. Am J Physiol Endocrinol Metab 2013; 304:E321-8. [PMID: 23233540 PMCID: PMC3566430 DOI: 10.1152/ajpendo.00324.2012] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Although much is known about the remodeling of high density lipoproteins (HDLs) in blood, there is no information on that in interstitial fluid, where it might have a major impact on the transport of cholesterol from cells. We incubated plasma and afferent (prenodal) peripheral lymph from 10 healthy men at 37°C in vitro and followed the changes in HDL subclasses by nondenaturing two-dimensional crossed immunoelectrophoresis and size-exclusion chromatography. In plasma, there was always initially a net conversion of small pre-β-HDLs to cholesteryl ester (CE)-rich α-HDLs. By contrast, in lymph, there was only net production of pre-β-HDLs from α-HDLs. Endogenous cholesterol esterification rate, cholesteryl ester transfer protein (CETP) concentration, CE transfer activity, phospholipid transfer protein (PLTP) concentration, and phospholipid transfer activity in lymph averaged 5.0, 10.4, 8.2, 25.0, and 82.0% of those in plasma, respectively (all P < 0.02). Lymph PLTP concentration, but not phospholipid transfer activity, was positively correlated with that in plasma (r = +0.63, P = 0.05). Mean PLTP-specific activity was 3.5-fold greater in lymph, reflecting a greater proportion of the high-activity form of PLTP. These findings suggest that cholesterol esterification rate and PLTP specific activity are differentially regulated in the two matrices in accordance with the requirements of reverse cholesterol transport, generating lipid-poor pre-β-HDLs in the extracellular matrix for cholesterol uptake from neighboring cells and converting pre-β-HDLs to α-HDLs in plasma for the delivery of cell-derived CEs to the liver.
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Kujiraoka T, Nakamoto T, Sugimura H, Iwasaki T, Ishihara M, Hoshi T, Horie Y, Ogawa K, Todoroki M, Nakatani Y, Banba N, Yasu T, Hattori H. Clinical Significance of Plasma Apolipoprotein F in Japanese Healthy and Hypertriglyceridemic Subjects. J Atheroscler Thromb 2013; 20:380-90. [DOI: 10.5551/jat.13706] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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Albers JJ, Vuletic S, Cheung MC. Role of plasma phospholipid transfer protein in lipid and lipoprotein metabolism. Biochim Biophys Acta Mol Cell Biol Lipids 2011; 1821:345-57. [PMID: 21736953 DOI: 10.1016/j.bbalip.2011.06.013] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2011] [Revised: 06/01/2011] [Accepted: 06/14/2011] [Indexed: 12/13/2022]
Abstract
The understanding of the physiological and pathophysiological role of PLTP has greatly increased since the discovery of PLTP more than a quarter of century ago. A comprehensive review of PLTP is presented on the following topics: PLTP gene organization and structure; PLTP transfer properties; different forms of PLTP; characteristics of plasma PLTP complexes; relationship of plasma PLTP activity, mass and specific activity with lipoprotein and metabolic factors; role of PLTP in lipoprotein metabolism; PLTP and reverse cholesterol transport; insights from studies of PLTP variants; insights of PLTP from animal studies; PLTP and atherosclerosis; PLTP and signal transduction; PLTP in the brain; and PLTP in human disease. PLTP's central role in lipoprotein metabolism and lipid transport in the vascular compartment has been firmly established. However, more studies are needed to further delineate PLTP's functions in specific tissues, such as the lung, brain and adipose tissue. Furthermore, the specific role that PLTP plays in human diseases, such as atherosclerosis, cancer, or neurodegenerative disease, remains to be clarified. Exciting directions for future research include evaluation of PLTP's physiological relevance in intracellular lipid metabolism and signal transduction, which undoubtedly will advance our knowledge of PLTP functions in health and disease. This article is part of a Special Issue entitled Advances in High Density Lipoprotein Formation and Metabolism: A Tribute to John F. Oram (1945-2010).
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Affiliation(s)
- John J Albers
- Northwest Lipid Metabolism and Diabetes Research Laboratories, Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, University of Washington, 401 Queen Anne Ave N, Seattle, WA 98109, USA.
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Omori M, Watanabe M, Matsumoto K, Honda H, Hattori H, Akizawa T. Impact of serum apolipoprotein A-IV as a marker of cardiovascular disease in maintenance hemodialysis patients. Ther Apher Dial 2010; 14:341-8. [PMID: 20609189 DOI: 10.1111/j.1744-9987.2010.00809.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The aim of this study was to investigate the relationship between serum apolipoprotein (apo) A-IV levels and markers for atherosclerosis, including carotid intima-media thickness (CIMT) and the ankle-brachial index (ABI), in hemodialysis patients. We performed a cross-sectional study involving 116 maintenance hemodialysis patients (70 males; median age, 64 years), measuring CIMT, ABI, the usual laboratory examinations, and serum apo A-IV before the dialysis session. The apo A-IV concentration was measured by a noncompetitive ELISA. Serum apo A-IV concentrations were significantly lower in hemodialysis patients with cardiovascular disease and plaque in the carotid artery. The apo A-IV level was positively associated with urea nitrogen and creatinine, and negatively associated with age, interleukin-6, the neutrophil/lymphocyte ratio, and maximum CIMT. Moreover, serum apo A-IV concentrations were significantly lower in the low ABI group. On logistic analysis, patients with high apo A-IV levels had a lower odds ratio for atherosclerosis (maximum CIMT > 1.0) and cardiovascular disease compared to patients with low apo A-IV levels. On stepwise multivariate regression analysis, the serum apo A-IV level was independently associated with creatinine, the neutrophil/lymphocyte ratio, and the maximum CIMT. Serum apo A-IV is associated with atherosclerotic lesions in hemodialysis patients. Apo A-IV levels may be useful for estimating the risk of cardiovascular disease in dialysis patients.
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Affiliation(s)
- Maho Omori
- Department of Nephrology, Gyoutoku Sougou Hospital, Chiba, Japan
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Karalis IK, Bergheanu SC, Wolterbeek R, Dallinga-Thie GM, Hattori H, van Tol A, Liem AH, Wouter Jukema J. Effect of increasing doses of Rosuvastatin and Atorvastatin on apolipoproteins, enzymes and lipid transfer proteins involved in lipoprotein metabolism and inflammatory parameters. Curr Med Res Opin 2010; 26:2301-13. [PMID: 20731529 DOI: 10.1185/03007995.2010.509264] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
UNLABELLED This paper contains detailed results of a sub-population of the prospective randomized RADAR (Rosuvastatin and Atorvastatin in different Dosages And Reverse cholesterol transport) study. OBJECTIVE Statin treatment results in substantially decreased incidence of cardiovascular events but the exact pathophysiological mechanism of their beneficial effect is yet unclear. We aimed to examine the effects of up-titrated doses of two widely used statins (atorvastatin (ATOR) and rosuvastatin (ROSU)) on parameters involved in lipoprotein metabolism, in patients with low high density lipoprotein cholesterol values (HDL-C). RESEARCH DESIGN AND METHODS In this RADAR substudy, 80 patients, aged 40-80 years, with known cardiovascular disease and low HDL-C (<1.0 mmol/l), were randomized to receive, after an initial 6 week dietary run-in phase, either ATOR 20 mg (n = 41) or ROSU 10 mg (n = 39). The doses were up-titrated (in 6 week intervals) to 80 mg of ATOR or 40 mg of ROSU at 12 weeks. Serum lipoproteins and lipoprotein metabolism parameters were measured at baseline and at 6 and 18 weeks of follow up. RESULTS Both statins significantly reduced total cholesterol (TChol) and non-HDL-C values with ROSU being more effective for the doses studied (p < 0.05). No statistically significant effect on HDL-C was observed for either statin. Apolipoproteins (apo) B, CI, CIII, AV and E were significantly reduced in both groups (p < 0.05), while the ratio of HDL particles containing both apoAI and apoAII (LpAI-AII) over HDL containing apoAI alone (LpAI) was changed for both statins with the decrease of LpAI being more prominent in the ATOR group (p = 0.028). Cholesterol ester transfer protein (CETP) mass and activity, phospholipid transfer protein (PLTP) activity and lipoprotein-associated phospholipase A2 (Lp-PLA2) mass and activity were all significantly reduced in both treatment groups over the follow-up period (p < 0.001). ATOR displayed a more prominent decrease of PLTP activity compared to ROSU (p = 0.043), while ROSU displayed a more prominent decrease of Lp-PLA2 activity compared to ATOR (p = 0.04). Both statins effectively reduced, in a dose-dependent way, high sensitivity C-reactive protein values over time, while no effect on the levels of circulating inter cellular adhesion molecule 1 (cICAM-1) was observed. CONCLUSIONS The effects of statin treatment extend further and beyond a mere TChol and LDL cholesterol reduction, as demonstrated by the aforementioned alterations of lipoproteins, enzymes and lipid transfer proteins involved in lipoprotein metabolism and pro-atherogenic and inflammatory molecules. ROSU and ATOR displayed a similar pattern of effect on lipid metabolism with discrete differences in the magnitude of this effect in certain variables. Despite the limitations of small population size and lack of clinical end points, reported data provide an insight for the possible pathophysiological mechanisms implicated in the effect of increasing dosages of different statin treatments.
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Henderson RJ, Leon CG, Wasan KM. Differences in human phospholipid transfer protein activity following incubation of Fungizone compared to lipid-based Amphotericin-B formulations in normolipidemic and hyperlipidemic plasma. Drug Dev Ind Pharm 2010; 35:1139-46. [PMID: 19381990 DOI: 10.1080/03639040902824852] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
AIM To investigate how different formulations of Amphotericin-B (Amp-B) affect the activity of phospholipid transfer protein (PLTP) when incubated with hyperlipidemic and normolipidemic plasma at physiological temperature (37 degrees C). METHODS Six hyperlipidemic and six normolipidemic plasma samples were collected and tested for protein concentration. Equivalent protein levels (25 microg) were then tested for PLTP activity using an in vitro established kit at physiological temperature (37 degrees C). Increasing concentrations of different Amp-B formulations (1, 2, and 5 microg/mL) in the pharmacological range were then added to the plasma and tested for activity from 5 to 90 minutes. The Amp-B formulations used in the study were Fungizone, Abelcet, and AmBisome. RESULTS In normolipidemic plasma, PLTP activity was found to be increased by Abelcet and AmBisome but inhibited by Fungizone. In hyperlipidemic plasma, PLTP activity was found to be increased by Abelcet and AmBisome but not changed by Fungizone. The Vm value for Abelcet and AmBisome was higher than Fungizone(; although, no difference was observed in the Km values between formulations. CONCLUSIONS Findings suggest that lipid-based formulations of Amp-B promote the transfer of Amp-B into high-density lipoprotein fractions at a degree of increase inversely proportional to the lipid levels in the plasma.
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Affiliation(s)
- Ryan J Henderson
- Division of Pharmaceutics and Biopharmaceutics, Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, British Columbia, Canada
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Henderson RJ, Wasan KM, Leon CG. Haptoglobin inhibits phospholipid transfer protein activity in hyperlipidemic human plasma. Lipids Health Dis 2009; 8:27. [PMID: 19627602 PMCID: PMC2729738 DOI: 10.1186/1476-511x-8-27] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2009] [Accepted: 07/23/2009] [Indexed: 12/16/2022] Open
Abstract
Background Haptoglobin is a plasma protein that scavenges haemoglobin during haemolysis. Phospholipid Transfer Protein (PLTP) transfers lipids from Low Density Lipoproteins (LDL) to High Density Lipoproteins (HDL). PLTP is involved in the pathogenesis of atherosclerosis which causes coronary artery disease, the leading cause of death in North America. It has been shown that Apolipoprotein-A1 (Apo-A1) binds and regulates PLTP activity. Haptoglobin can also bind to Apo-A1, affecting the ability of Apo-A1 to induce enzymatic activities. Thus we hypothesize that haptoglobin inhibits PLTP activity. This work tested the effect of Haptoglobin and Apo-A1 addition on PLTP activity in human plasma samples. The results will contribute to our understanding of the role of haptoglobin on modulating reverse cholesterol transport. Results We analyzed the PLTP activity and Apo-A1 and Haptoglobin content in six hyperlipidemic and six normolipidemic plasmas. We found that Apo-A1 levels are proportional to PLTP activity in hyperlipidemic (R2 = 0.66, p < 0.05) but not in normolipidemic human plasma. Haptoglobin levels and PLTP activity are inversely proportional in hyperlipidemic plasmas (R2 = 0.57, p > 0.05). When the PLTP activity was graphed versus the Hp/Apo-A1 ratio in hyperlipidemic plasma there was a significant correlation (R2 = 0.69, p < 0.05) suggesting that PLTP activity is affected by the combined effect of Apo-A1 and haptoglobin. When haptoglobin was added to individual hyperlipidemic plasma samples there was a dose dependent decrease in PLTP activity. In these samples we also found a negative correlation (-0.59, p < 0.05) between PLTP activity and Hp/Apo-A1. When we added an amount of haptoglobin equivalent to 100% of the basal levels, we found a 64 ± 23% decrease (p < 0.05) in PLTP activity compared to basal PLTP activity. We tested the hypothesis that additional Apo-A1 would induce PLTP activity. Interestingly we found a dose dependent decrease in PLTP activity upon Apo-A1 addition. When both Apo-A1 and Hpt were added to the plasma samples there was no further reduction in PLTP activity suggesting that they act through a common pathway. Conclusion These findings suggest an inhibitory effect of Haptoglobin over PLTP activity in hyperlipidemic plasma that may contribute to the regulation of reverse cholesterol transport.
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Affiliation(s)
- Ryan J Henderson
- Division of Pharmaceutics and Biopharmaceutics, Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, British Columbia V6T1Z3, Canada.
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Ataxia with vitamin E deficiency with a mutation in a phospholipid transfer protein gene. J Neurol 2009; 256:1180-1. [PMID: 19252769 DOI: 10.1007/s00415-009-5075-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2008] [Revised: 01/23/2009] [Accepted: 02/12/2009] [Indexed: 02/06/2023]
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Samyn H, Moerland M, van Gent T, van Haperen R, Metso J, Grosveld F, Jauhiainen M, van Tol A, de Crom R. Plasma phospholipid transfer activity is essential for increased atherogenesis in PLTP transgenic mice: a mutation-inactivation study. J Lipid Res 2008; 49:2504-12. [DOI: 10.1194/jlr.m800080-jlr200] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Vergeer M, Dallinga-Thie GM, Dullaart RPF, van Tol A. Evaluation of phospholipid transfer protein as a therapeutic target. ACTA ACUST UNITED AC 2008. [DOI: 10.2217/17460875.3.3.327] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Pitarch A, Nombela C, Gil C. Reliability of antibodies to Candida methionine synthase for diagnosis, prognosis and risk stratification in systemic candidiasis: A generic strategy for the prototype development phase of proteomic markers. Proteomics Clin Appl 2007; 1:1221-42. [PMID: 21136621 DOI: 10.1002/prca.200601036] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2006] [Indexed: 11/10/2022]
Abstract
To be able to diagnose systemic candidiasis (SC) and to predict outcomes in SC patients are still challenging tasks for physicians. Previous proteomic studies suggest that anti-Candida methionine synthase (Met6p) IgG antibodies may be a candidate marker for SC. To evaluate their reliability for diagnosis, prognosis and risk stratification in SC, we developed a generic prototype strategy for their measurement in SC. Receiver-operating-characteristic curve analyses revealed a high diagnostic accuracy for this prototype format, which was slightly better to that for the widely used Western blot assays. Multivariate logistic-regression models showed a positive association between serum anti-Met6p IgG antibody levels and SC risk that was independent from established SC risk factors and other baseline variables. After adjusting for and stratifying according to known prognostic factors, a significant trend toward a lower two-month mortality risk with increasing levels was evidenced in SC patients at presentation. We conclude that these antibodies may be useful in discriminating SC from non-SC patients and determining risk stratification in SC. These may also confer protection against SC and be valuable for the design of future immunotherapies. Furthermore, our prototype format has the potential to make impact on other infectious diseases, cancers, allergies or autoimmune disorders.
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Affiliation(s)
- Aida Pitarch
- Department of Microbiology II, Faculty of Pharmacy, Complutense University of Madrid, Madrid, Spain
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Dallinga-Thie GM, Dullaart RPF, van Tol A. Concerted actions of cholesteryl ester transfer protein and phospholipid transfer protein in type 2 diabetes: effects of apolipoproteins. Curr Opin Lipidol 2007; 18:251-7. [PMID: 17495597 DOI: 10.1097/mol.0b013e3280e12685] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE OF REVIEW Type 2 diabetes frequently coincides with dyslipidemia, characterized by elevated plasma triglycerides, low high-density lipoprotein cholesterol levels and the presence of small dense low-density lipoprotein particles. Plasma lipid transfer proteins play an essential role in lipoprotein metabolism. It is thus vital to understand their pathophysiology and determine which factors influence their functioning in type 2 diabetes. RECENT FINDINGS Cholesteryl ester transfer protein-mediated transfer is increased in diabetic patients and contributes to low plasma high-density lipoprotein cholesterol levels. Apolipoproteins A-I, A-II and E are components of the donor lipoprotein particles that participate in the transfer of cholesteryl esters from high-density lipoprotein to apolipoprotein B-containing lipoproteins. Current evidence for functional roles of apolipoproteins C-I, F and A-IV as modulators of cholesteryl ester transfer is discussed. Phospholipid transfer protein activity is increased in diabetic patients and may contribute to hepatic very low-density lipoprotein synthesis and secretion and vitamin E transfer. Apolipoprotein E could stimulate the phospholipid transfer protein-mediated transfer of surface fragments of triglyceride-rich lipoproteins to high-density lipoprotein, and promote high-density lipoprotein remodelling. SUMMARY Both phospholipid and cholesteryl ester transfer proteins are important in very low and high-density lipoprotein metabolism and display concerted actions in patients with type 2 diabetes.
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Affiliation(s)
- Geesje M Dallinga-Thie
- Department of Vascular Medicine, Erasmus University Medical Center, Rotterdam, The Netherlands.
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Tan KCB, Shiu SWM, Wong Y, Wong WK, Tam S. Plasma apolipoprotein E concentration is an important determinant of phospholipid transfer protein activity in type 2 diabetes mellitus. Diabetes Metab Res Rev 2006; 22:307-12. [PMID: 16389649 DOI: 10.1002/dmrr.616] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND Phospholipid transfer protein (PLTP) transfers phospholipids between lipoproteins and plays an important role in HDL metabolism. PLTP exists as a high-activity and a low-activity form in the circulation. In vitro studies have shown that apolipoprotein (apo) E is involved in maintaining PLTP in the active form, while the low-activity form is associated with apo AI. We have therefore investigated whether plasma apo AI, B and E concentrations are important determinants of plasma PLTP activity in type 2 diabetes, a condition associated with increased plasma PLTP activity. METHODS Plasma PLTP activity was assayed by measuring the transfer of radiolabelled phosphatidylcholine from liposomes to HDL; apo AI and B by rate nephelometry and apo E by a 2-point turbidimetric assay. RESULTS Type 2 diabetic patients (n = 230) had higher PLTP activity than controls (n = 97) (2374 +/- 628 nmol/mL/h versus 1862 +/- 585 respectively, p < 0.01). They also had increased fasting triglyceride and low HDL. Plasma apo B (p < 0.01) and apo E (p < 0.05) were increased, whereas apo AI was reduced (p < 0.01). Univariate analysis showed that plasma PLTP activity correlated mainly with apolipoproteins AI and E. Stepwise regression analysis showed that apo E was the main determinant of plasma PLTP activity, accounting for 23% of its variability in the diabetic subjects and 8% in the controls respectively. CONCLUSIONS The associations between plasma apo AI and E concentrations and PLTP activity suggest that these apolipoproteins are important regulators of PLTP activity in vivo. The increase in PLTP activity in type 2 diabetes is partly related to the changes in these apolipoproteins.
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Affiliation(s)
- K C B Tan
- Department of Medicine, University of Hong Kong, Queen Mary Hospital, Pokfulam Road, Hong Kong.
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Dallinga-Thie GM, van Tol A, Hattori H, Rensen PCN, Sijbrands EJG. Plasma phospholipid transfer protein activity is decreased in type 2 diabetes during treatment with atorvastatin: a role for apolipoprotein E? Diabetes 2006; 55:1491-6. [PMID: 16644710 DOI: 10.2337/db05-1685] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Plasma phospholipid transfer protein (PLTP) plays an important role in lipoprotein metabolism. PLTP activity is elevated in patients with diabetes, a condition with strongly elevated risk for coronary heart disease. The aim of this study was to test the hypothesis that statins reduce PLTP activity and to examine the potential role of apolipoprotein E (apoE). PLTP activity and apoE were measured in patients with type 2 diabetes from the DALI (Diabetes Atorvastatin Lipid Intervention) Study, a 30-week randomized double-blind placebo-controlled trial with atorvastatin (10 and 80 mg daily). At baseline, PLTP activity was positively correlated with waist circumference, HbA(1c), glucose, and apoE (all P < 0.05). Atorvastatin treatment resulted in decreased PLTP activity (10 mg atorvastatin: -8.3%, P < 0.05; 80 mg atorvastatin: -12.1%, P < 0.002). Plasma apoE decreased by 28 and 36%, respectively (P < 0.001). The decrease in apoE was strongly related to the decrease in PLTP activity (r = 0.565, P < 0.001). The change in apoE remained the sole determinant of the change in PLTP activity in a multivariate model. The activity of PLTP in type 2 diabetes is decreased by atorvastatin. The association between the decrease in PLTP activity and apoE during statin treatment supports the hypothesis that apoE may prevent PLTP inactivation.
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Affiliation(s)
- Geesje M Dallinga-Thie
- Department of Internal Medicine, Vascular and Metabolic Diseases, Bd 277, Erasmus Medical Center, Dr Molewaterplein 40, 3000 CA Rotterdam, Netherlands.
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Vuletic S, Peskind ER, Marcovina SM, Quinn JF, Cheung MC, Kennedy H, Kaye JA, Jin LW, Albers JJ. Reduced CSF PLTP activity in Alzheimer's disease and other neurologic diseases; PLTP induces ApoE secretion in primary human astrocytes in vitro. J Neurosci Res 2005; 80:406-13. [PMID: 15795933 DOI: 10.1002/jnr.20458] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Phospholipid transfer protein (PLTP) plays a pivotal role in cellular lipid efflux and modulation of lipoprotein metabolism. PLTP is distributed widely in the central nervous system (CNS), is synthesized by glia and neurons, and is active in cerebrospinal fluid (CSF). The aims of this study were to test the hypothesis that patients with Alzheimer's disease (AD) have altered PLTP-mediated phospholipid transfer activity in CSF, and to examine the potential relationship between PLTP activity and apolipoprotein E (apoE) levels in CSF. We assessed PLTP activity and apoE concentration in CSF of patients with probable AD (n = 50), multiple sclerosis (MS; n = 9), other neurologic diseases (n = 21), and neurologically healthy controls (n = 40). PLTP activity in AD was reduced compared to that in controls (P < 0.001), with approximately half of the AD patients with PLTP activity values below all controls. Patients with MS had lower PLTP activity than AD patients (P < 0.001). PLTP activity was highly correlated with PLTP mass, as estimated by Western blot (r = 0.006; P < 0.01). CSF PLTP activity positively correlated with apoE concentration in AD (R = 0.435; P = 0.002) and controls (R = 0.456; P = 0.003). Anti-apoE immunoaffinity chromatography and Western blot analyses indicated that some CSF PLTP is associated with apoE-containing lipoproteins. Exogenous addition of recombinant PLTP to primary human astrocytes significantly increased apoE secretion to the conditioned medium. The findings of reduced PLTP activity in AD CSF, and the observation that PLTP can influence apoE secretion in astrocytes suggest a potential link between alterations in the brain lipid metabolism and AD pathogenesis.
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Affiliation(s)
- Simona Vuletic
- Department of Medicine, Northwest Lipid Metabolism and Diabetes Research Laboratories, University of Washington, Seattle, Washington 98109-4517, USA
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17
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Oomen PHN, van Tol A, Hattori H, Smit AJ, Scheek LM, Dullaart RPF. Human plasma phospholipid transfer protein activity is decreased by acute hyperglycaemia: studies without and with hyperinsulinaemia in Type 1 diabetes mellitus. Diabet Med 2005; 22:768-74. [PMID: 15910630 DOI: 10.1111/j.1464-5491.2005.01521.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
AIMS Little is known about the regulation of phospholipid transfer protein (PLTP), that plays a key role in lipoprotein metabolism. PLTP secretion may be up-regulated by glucose in vitro, whereas plasma PLTP activity is decreased by exogenous hyperinsulinaemia and glucose-induced hyperinsulinaemia in vivo. In the present study, we evaluated the separate effects of hyperglycaemia and hyperinsulinaemia in C-peptide-negative Type 1 diabetic patients. METHODS The protocol was carried out in 16 patients (eight females). In each individual, plasma PLTP mass and activity (measured by enzyme-linked immuno-sorbent assay and liposome-high density lipoprotein system, respectively) as well as plasma cholesteryl ester transfer protein (CETP) activity, lipids and apolipoprotein levels were determined at the end of four different glucose clamps, each lasting 210 min: standard insulin (30 mU/kg/h) and standard glucose (glucose 5.0 mmol/l) (SI-SG), standard insulin and high glucose (glucose 12 mmol/l) (SI-HG), high insulin (150 mU/kg/h) and standard glucose (HI-SG), and high insulin and high glucose (HI-HG). RESULTS Plasma lipids and (apo)lipoproteins, measured at the end of the SI-HG, HI-SG and HI-HG clamps, were not significantly different compared with the levels obtained at the end of the SI-SG clamp. Median plasma PLTP mass and activity at the end of the SI-SG clamp were 12.8 mg/l and 13.2 micromol/ml/h, respectively. Median plasma PLTP mass decreased by 9.1% at the end of the HI-HG clamp (P < 0.01), whereas the changes at the end of the SI-HG and HI-SG clamps were not significant. Median plasma PLTP activity decreased by 5.7, 4.6 and 8.6% at the end of the SI-HG, HI-SG and HI-HG clamps, respectively (all P < 0.05). Median plasma CETP activity was 177 nmol/ml/h at the end of the SI-SG clamp, and decreased by 4.9% (P < 0.05) and by 8.3% (P < 0.05) at the end of the HI-SG and the HI-HG clamps, respectively. Plasma CETP activity did not change significantly at the end of the SI-HG clamp. CONCLUSIONS The present study demonstrates that plasma PLTP activity is independently decreased by acute hyperglycaemia and hyperinsulinaemia in humans in vivo. These data do not support a direct role of short-term hyperglycaemia in up-regulating plasma PLTP levels.
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Affiliation(s)
- P H N Oomen
- Department of Endocrinology, University Hospital Groningen, Groningen, The Netherlands.
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18
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Palmen J, Colhoun HM, Van Tol A, Hattori H, Humphries SE. A novel common variant −181 G insertion in the promoter of the gene for phospholipid transfer protein. Atherosclerosis 2005; 180:211-3. [PMID: 15823296 DOI: 10.1016/j.atherosclerosis.2004.12.027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2004] [Revised: 11/29/2004] [Accepted: 12/03/2004] [Indexed: 11/25/2022]
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19
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Tan KCB, Shiu SWM, Wong Y, Tam S. Plasma phospholipid transfer protein activity and subclinical inflammation in type 2 diabetes mellitus. Atherosclerosis 2005; 178:365-70. [PMID: 15754464 DOI: 10.1016/j.atherosclerosis.2004.09.005] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Phospholipid transfer protein (PLTP) transfers phospholipids between lipoproteins, and plays an essential role in HDL metabolism. The regulation of PLTP is poorly understood and recent evidence suggests that PLTP activity increases during acute-phase response. Since type 2 diabetes is associated with chronic subclinical inflammation, the objective is to determine whether inflammation modulates PLTP in diabetes. Plasma PLTP activity was assayed by measuring the transfer of radiolabeled phosphatidylcholine from liposomes to HDL and high-sensitivity C-reactive protein (CRP) by immunoturbidimetric assay in 280 type 2 diabetic patients and 105 controls. Plasma PLTP activity (2364+/-651 nmol/ml/h versus 1880+/-586 nmol/ml/h in control, mean +/- S.D., P <0.01) and CRP (1.64(0.89-3.23)mg/l versus 0.99(0.53-2.23 mg/l, median (interquartile range), P<0.01) were increased in diabetic subjects. PLTP activity correlated significantly with age, BMI, HbA1c, log(CRP) and apolipoprotein AI and B in diabetic subjects. General linear model analysis showed that only apolipoprotein AI, age, BMI, and log(CRP) were independent determinants of PLTP activity. In conclusion, PLTP activity is increased in diabetes and apolipoprotein AI is a major determinant of PLTP activity. There is also an independent association between CRP and PLTP activity, suggesting that subclinical inflammation may influence PLTP activity in diabetes.
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Affiliation(s)
- K C B Tan
- Department of Medicine, Queen Mary Hospital, University of Hong Kong, Pokufulam Road, Hong Kong, Hong Kong.
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20
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Yatsuya H, Tamakoshi K, Hattori H, Otsuka R, Wada K, Zhang H, Mabuchi T, Ishikawa M, Murata C, Yoshida T, Kondo T, Toyoshima H. Serum phospholipid transfer protein mass as a possible protective factor for coronary heart diseases. Circ J 2004; 68:11-6. [PMID: 14695459 DOI: 10.1253/circj.68.11] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND Phospholipid transfer protein (PLTP) can generate pre-beta high-density lipoprotein (HDL), an efficient acceptor of peripheral cholesterol, by mediating a process called HDL conversion. The transfer of phospholipids to immature HDL is also essential in maintaining reverse cholesterol transport. The phospholipid transfer activity of PLTP has been associated with various patho-physiological conditions; however, little information is available concerning the relationship between PLTP mass and disease. METHODS AND RESULTS Using a sandwich enzyme-linked immunosorbent assay, PLTP concentration was measured and related to the risk of developing cardiovascular disease in a worksite-based cohort of Japanese men (n=2,567). Multiple linear regression analysis showed significant associations between PLTP and HDL cholesterol, triglycerides, low-density lipoprotein cholesterol, and body mass index (standardized beta=0.395, -0.191, -0.064, and -0.064, respectively; R(2)=0.31). During the follow-up period, there were 10 cases of coronary heart disease (CHD) and 7 of stroke. The multivariate adjusted relative risk of CHD was 0.46 (95% confidence interval, 0.20-1.07) for an increase of 1 standard deviation in the PLTP value (p=0.071). PLTP concentration was not related to the risk of stroke. CONCLUSIONS The results of this prospective study indicate that the serum PLTP concentration would serve as a predictor of CHD, independent of HDL cholesterol, triglycerides and other established risk factors.
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Affiliation(s)
- Hiroshi Yatsuya
- Department of Public Health/Health Information Dynamics, Nagoya University Graduate School of Medicine, Japan
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Siggins S, Kärkkäinen M, Tenhunen J, Metso J, Tahvanainen E, Olkkonen VM, Jauhiainen M, Ehnholm C. Quantitation of the active and low-active forms of human plasma phospholipid transfer protein by ELISA. J Lipid Res 2003; 45:387-95. [PMID: 14617737 DOI: 10.1194/jlr.d300023-jlr200] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human plasma contains two forms of phospholipid transfer protein (PLTP), one catalytically active [high-activity PLTP (HA-PLTP)] and the other a low-activity (LA-PLTP) form. We present here a PLTP ELISA that allows not only for accurate measurement of PLTP concentration in plasma but also of the distribution of both LA- and HA-PLTP. To achieve similar immunoreactivity of the two PLTP forms, a denaturing sample pretreatment with 0.5% SDS was required. Distribution of LA- and HA-PLTP in plasma was assessed using size-exclusion chromatography, Heparin-Sepharose chromatography, anti-PLTP immunoaffinity chromatography, and dextran sulfate-CaCl2 precipitation. All four methods demonstrated that approximately 60% of plasma PLTP represents LA-PLTP and 40% represents HA-PLTP. According to the modified ELISA, the total serum PLTP concentration in a random Finnish population sample (n = 80) was 5.81 +/- 1.33 mg/l (mean +/- SD) (range, 2.78-10.06 mg/l) and the mean activity was 5.84 +/- 1.39 micromol/ml/h (range, 3.21-11.15 micromol/ml/h). To quantitate both forms of PLTP in sera from this sample, we combined dextran sulfate-CaCl2 precipitation with the modified PLTP ELISA. The HA-PLTP mass (mean, 1.87 +/- 0.85 mg/l) correlated significantly with serum PLTP activity, whereas that of LA-PLTP (mean, 3.94 +/- 1.4 mg/l) showed no correlation with phospholipid transfer activity.
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Affiliation(s)
- Sarah Siggins
- Department of Molecular Medicine, National Public Health Institute, Biomedicum, FIN-00251 Helsinki, Finland
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22
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Kujiraoka T, Iwasaki T, Ishihara M, Ito M, Nagano M, Kawaguchi A, Takahashi S, Ishi J, Tsuji M, Egashira T, Stepanova IP, Miller NE, Hattori H. Altered distribution of plasma PAF-AH between HDLs and other lipoproteins in hyperlipidemia and diabetes mellitus. J Lipid Res 2003; 44:2006-14. [PMID: 12867534 DOI: 10.1194/jlr.d300021-jlr200] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Platelet-activating factor acetylhydrolase (PAF-AH) is a phospholipase A2 associated with lipoproteins that hydrolyzes platelet-activating factor (PAF) and oxidized phospholipids. We have developed an ELISA for PAF-AH that is more sensitive than previous methods, and have quantified HDL-associated and non-HDL-associated PAF-AH in healthy, hyperlipidemic, and diabetic subjects. In healthy subjects, plasma total PAF-AH concentration was positively correlated with PAF-AH activity and with plasma total cholesterol, triacylglycerol, LDL cholesterol and apolipoprotein B (apoB) concentrations (all P < 0.01). HDL-associated PAF-AH concentration was correlated positively with plasma apoA-I and HDL cholesterol. Subjects with hyperlipidemia (n = 73) and diabetes mellitus (n = 87) had higher HDL-associated PAF-AH concentrations than did controls (P < 0.01). Non-HDL-associated PAF-AH concentration was lower in diabetic subjects than in controls (P < 0.01). Both hyperlipidemic and diabetic subjects had lower ratios of PAF-AH to apoB (P < 0.01) and higher ratios of PAF-AH to apoA-I (P < 0.01) than did controls. Our results show that the distribution of PAF-AH mass between HDLs and LDLs is determined partly by the concentrations of the lipoproteins and partly by the mass of enzyme per lipoprotein particle, which is disturbed in hyperlipidemia and diabetes mellitus.
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Affiliation(s)
- Takeshi Kujiraoka
- Department of Advanced Medical Technology and Development, BML, Inc., Saitama, Japan
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23
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Kujiraoka T, Nanjee MN, Oka T, Ito M, Nagano M, Cooke CJ, Takahashi S, Olszewski WL, Wong JS, Stepanova IP, Hamilton RL, Egashira T, Hattori H, Miller NE. Effects of intravenous apolipoprotein A-I/phosphatidylcholine discs on LCAT, PLTP, and CETP in plasma and peripheral lymph in humans. Arterioscler Thromb Vasc Biol 2003; 23:1653-9. [PMID: 12893687 DOI: 10.1161/01.atv.0000089328.23279.3f] [Citation(s) in RCA: 38] [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
OBJECTIVE We have previously shown that intravenous apolipoprotein A-I/phosphatidylcholine (apoA-I/PC) discs increase plasma pre-beta HDL concentration and stimulate reverse cholesterol transport (RCT) in humans. We have now investigated the associated changes in the following 3 HDL components that play key roles in RCT: lecithin:cholesterol acyltransferase (LCAT), cholesteryl ester transfer protein (CETP), and phospholipid transfer protein (PLTP). METHODS AND RESULTS apoA-I/PC discs (40 mg/kg over 4 hours) were infused into 8 healthy men. Samples of blood and prenodal peripheral lymph were collected for 24 to 48 hours. At 12 hours, plasma LCAT concentration had increased by 0.40+/-0.90 mg/L (+7.8%; mean+/-SD; P<0.05), plasma cholesterol esterification rate by 29.0+/-9.0 nmol/mL per h (+69.5%; P<0.01), plasma CETP concentration by 0.5+/-0.2 mg/L (+29.7%; P<0.01), and plasma PLTP activity by 1.45+/-0.67 micromol/mL per h (+23.9%; P<0.01). In contrast, plasma PLTP concentration had decreased by 4.4+/-2.7 mg/L (-44.8%; P<0.01). The changes in PLTP were accompanied by alterations in the relative proportions of large lipoproteins containing inactive PLTP and small particles containing PLTP of high specific activity. No changes were detected in peripheral lymph. CONCLUSIONS Nascent HDL secretion may induce changes in PLTP, LCAT, and CETP that promote RCT by catalyzing pre-beta HDL production, cholesterol esterification in HDLs, and cholesteryl ester transfer from HDLs to other lipoproteins.
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Affiliation(s)
- Takeshi Kujiraoka
- Department of Advanced Medical Technology and Development, BML, Inc, 1361-1 Matoba, Kawagoe, Saitama 350-1101, Japan
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24
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Siggins S, Jauhiainen M, Olkkonen VM, Tenhunen J, Ehnholm C. PLTP secreted by HepG2 cells resembles the high-activity PLTP form in human plasma. J Lipid Res 2003; 44:1698-704. [PMID: 12810820 DOI: 10.1194/jlr.m300059-jlr200] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Plasma phospholipid transfer protein (PLTP) is an important regulator of plasma HDL levels and HDL particle distribution. PLTP is present in plasma in two forms, one with high and the other with low phospholipid transfer activity. We have used the human hepatoma cell line, HepG2, as a model to study PLTP secreted from hepatic cells. PLTP activity was secreted by the cells into serum-free culture medium as a function of time. However, modification of a previously established ELISA assay to include a denaturing sample pretreatment with the anionic detergent sodium dodecyl sulphate was required for the detection of the secreted PLTP protein. The HepG2 PLTP could be enriched by Heparin-Sepharose affinity chromatography and eluted in size-exclusion chromatography at a position corresponding to the size of 160 kDa. PLTP coeluted with apolipoprotein E (apoE) but not with apoB-100 or apoA-I. A portion of PLTP was retained by an anti-apoE immunoaffinity column together with apoE, suggesting an interaction between these two proteins. Furthermore, antibodies against apoE but not those against apoB-100 or apoA-I were capable of inhibiting PLTP activity. These results show that the HepG2-derived PLTP resembles in several aspects the high-activity form of PLTP found in human plasma.
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Affiliation(s)
- Sarah Siggins
- National Public Health Institute, Department of Molecular Medicine, Biomedicum, P.O. Box 104, FIN-00251 Helsinki, Finland
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25
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Jonkers IJAM, Smelt AHM, Hattori H, Scheek LM, van Gent T, de Man FHAF, van der Laarse A, van Tol A. Decreased PLTP mass but elevated PLTP activity linked to insulin resistance in HTG: effects of bezafibrate therapy. J Lipid Res 2003; 44:1462-9. [PMID: 12754275 DOI: 10.1194/jlr.m300008-jlr200] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Hypertriglyceridemia (HTG) is associated with insulin resistance, increased cholesteryl ester transfer (CET), and low HDL cholesterol. Phospholipid transfer protein (PLTP) may be involved in these relationships. Associations between CET, lipids, insulin resistance, CETP and PLTP activities, and PLTP mass were investigated in 18 HTG patients and 20 controls. Effects of 6 weeks of bezafibrate treatment were studied in HTG patients. HTG patients had higher serum triglycerides, insulin resistance, free fatty acid (FFA), and CET, lower levels of HDL cholesterol (-44%) and PLTP mass (-54%), and higher CETP (+20%) and PLTP activity (+48%) than controls. Bezafibrate reduced triglycerides, CET (-37%), insulin resistance (-53%), FFA (-48%), CETP activity (-12%), PLTP activity (-8%), and increased HDL cholesterol (+27%), whereas PLTP mass remained unchanged. Regression analysis showed a positive contribution of PLTP mass (P = 0.001) but not of PLTP activity to HDL cholesterol, whereas insulin resistance positively contributed to PLTP activity (P < 0.01). Bezafibrate-induced change in CET and HDL cholesterol correlated with changes in CETP activity and FFAs, but not with change in PLTP activity. Bezafibrate-induced change in PLTP activity correlated with change in FFAs (r = 0.455, P = 0.058). We propose that elevated PLTP activity in HTG is related to insulin resistance and not to increased PLTP mass. Bezafibrate-induced diminished insulin resistance is associated with a reduction of CET and PLTP activity.
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Affiliation(s)
- Iris J A M Jonkers
- Department of General Internal Medicine, Leiden University Medical Center, Leiden, The Netherlands
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26
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Kotake H, Sekikawa A, Tokita Y, Ishigaki Y, Oikawa S. Effect of HMG-CoA reductase inhibitor on plasma cholesteryl ester transfer protein activity in primary hypercholesterolemia: comparison among CETP/TaqIB genotype subgroups. J Atheroscler Thromb 2003; 9:207-12. [PMID: 12409629 DOI: 10.5551/jat.9.207] [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: 11/11/2022] Open
Abstract
We investigated the effects of HMG-CoA reductase inhibitors (statins) on the activity and concentration of plasma cholesterol ester transfer protein (CETP) in 30 hypercholesterolemic patients. Patients were divided into three groups according to TaqIB polymorphism of the CETP gene. The activity (158 +/- 23% control, mean +/- SEM) and concentration (4.1 +/- 1.0 mg/l) of plasma CETP were significantly (p < 0.005) higher in the subjects with the B1B1 genotype than B2B2 genotype (106 +/- 25% and 2.5 +/- 1.1 mg/l, respectively). Plasma CETP activity and concentration levels in the B1B2 group were intermediate between those of the B1B1 and B2B2 groups, and significantly (p < 0.05) low compared with the B1B1 group.Both the activity and concentration of plasma CETP were positively correlated with the LDL-cholesterol concentration (r = 0.608, p < 0.0005 and r = 0.552, p < 0.005, respectively). The administration of statins significantly reduced not only the activity (p < 0.01) but also the concentration (p < 0.05) of plasma CETP in hypercholesterolemic patients. Taken together, we confirmed that statins would be effective in increasing HDL levels in Japanese B1B1 carriers, because of a lower concentration of HDL cholesterol and higher level of plasma CETP compared to the other genotypes. The genetic variation in the CETP gene may be one important factor in designing better treatments.
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Affiliation(s)
- Hidetoshi Kotake
- Division of Endocrinology and Metabolism, Tohoku University School of Medicine, Miyagi, Japan
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27
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Lie J, de Crom R, van Gent T, van Haperen R, Scheek L, Lankhuizen I, van Tol A. Elevation of plasma phospholipid transfer protein in transgenic mice increases VLDL secretion. J Lipid Res 2002; 43:1875-80. [PMID: 12401886 DOI: 10.1194/jlr.m200166-jlr200] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Two lipid transfer proteins are active in human plasma, cholesteryl ester transfer protein (CETP), and phospholipid transfer protein (PLTP). Mice by nature do not express CETP. Additional inactivation of the PLTP gene resulted in reduced secretion of VLDL and subsequently in decreased susceptibility to diet-induced atherosclerosis. The aim of this study is to assess possible effects of differences in PLTP expression on VLDL secretion in mice that are proficient in CETP and PLTP. We compared human CETP transgenic (huCETPtg) mice with mice expressing both human lipid transfer proteins (huCETPtg/huPLTPtg). Plasma cholesterol in huCETPtg mice was 1.5-fold higher compared with huCETPtg/huPLTPtg mice (P < 0.001). This difference was mostly due to a lower HDL level in the huCETPtg/huPLTPtg mice, which subsequently could lead to the somewhat decreased CETP activity and concentration that was found in huCETPtg/huPLTPtg mice (P < 0.05). PLTP activity was 2.8-fold increased in these animals (P < 0.001). The human PLTP concentration was 5 microg/ml. Moderate overexpression of PLTP resulted in a 1.5-fold higher VLDL secretion compared with huCETPtg mice (P < 0.05). The composition of nascent VLDL was similar in both strains. These results indicate that elevated PLTP activity in huCETPtg mice results in an increase in VLDL secretion. In addition, PLTP overexpression decreases plasma HDL cholesterol as well as CETP.
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Affiliation(s)
- Jessica Lie
- Department of Biochemistry, Erasmus Medical Center, PO Box 1738, 3000 DR Rotterdam, The Netherlands
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Oka T, Yamashita S, Kujiraoka T, Ito M, Nagano M, Sagehashi Y, Egashira T, Nanjee MN, Hirano KI, Miller NE, Matsuzawa Y, Hattori H. Distribution of human plasma PLTP mass and activity in hypo- and hyperalphalipoproteinemia. J Lipid Res 2002. [DOI: 10.1194/jlr.m100349-jlr200] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Kärkkäinen M, Oka T, Olkkonen VM, Metso J, Hattori H, Jauhiainen M, Ehnholm C. Isolation and partial characterization of the inactive and active forms of human plasma phospholipid transfer protein (PLTP). J Biol Chem 2002; 277:15413-8. [PMID: 11854286 DOI: 10.1074/jbc.m112247200] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Plasma phospholipid transfer protein (PLTP) plays an important role in lipoprotein metabolism. Two forms of PLTP exist in human plasma, one catalytically active (high activity form, HA-PLTP) and the other inactive (low activity form, LA-PLTP) (Oka, T., Kujiraoka, T., Ito, M., Egashira, T., Takahashi, S., Nanjee, N. M., Miller, N. E., Metso, J., Olkkonen, V. M., Ehnholm, C., Jauhiainen, M., and Hattori, H. (2000) J. Lipid Res. 41, 1651-1657). The two forms are associated with macromolecular complexes of different size. The apparent size of LA-PLTP is 520 kDa and that of HA-PLTP is 160 kDa. Of the circulating PLTP mass only a minor portion is in the HA-PLTP form in normolipidemic subjects. In the present study we have isolated and partially characterized the LA and HA forms of PLTP. Both LA- and HA-PLTP bind to heparin-Sepharose and can be separated by elution with 0-0.5 m NaCl gradient, with HA-PLTP displaying higher affinity for the matrix. LA-PLTP was further purified using hydrophobic butyl-Sepharose and anti-PLTP immunoaffinity chromatography steps. HA-PLTP was subjected to a second heparin-Sepharose step and hydroxylapatite chromatography. Analysis of the two forms of PLTP by SDS-PAGE, Western blotting, immunoprecipitation, and gel filtration demonstrates that LA-PLTP is complexed with apoA-I whereas HA-PLTP is not. Instead, HA-PLTP copurified with apoE. Based on these findings we suggest a model in which nascent PLTP enters the circulation as a high specific activity form not associated with apoA-I. During or after the transfer of lipolytic surface remnants to HDL, PLTP is transferred to apoA-I-containing HDL particles and thereby becomes part of the low activity complex.
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Affiliation(s)
- Minna Kärkkäinen
- Department of Molecular Medicine, National Public Health Institute, Biomedicum, P. O. Box 104, Helsinki FIN-00251, Finland
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Abstract
A role for phospholipid transfer protein (PLTP) in HDL remodelling and in the formation of pre-beta-HDL is now well established, both in vivo and in vitro. Over-expression of human PLTP in C57BL6 mice lowers plasma HDL levels, probably because of increased HDL catabolism. Despite these low HDL levels, plasma from these mice mitigates cholesterol accumulation in macrophages and has increased potential for pre-beta-HDL formation. Plasma HDL concentration is also decreased in PLTP knockout mice. These intriguing observations can be explained by recent studies that indicate that PLTP is not only involved in remodelling of HDL subfractions but also in VLDL turnover. The role of PLTP in atherogenesis and VLDL synthesis was demonstrated in transgenic mouse models with increased susceptibility for the development of atherosclerosis, bred into PLTP knockout mice. The data clearly show that PLTP can be proatherogenic. As mentioned above, however, PLTP may have antiatherogenic potential in wild-type C57BL6 mice. Information regarding the role and regulation of PLTP in human (patho)physiology is still relatively sparse but accumulating rapidly. PLTP activity is elevated in diabetes mellitus (both type 1 and type 2), obesity and insulin resistance.
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Affiliation(s)
- Arie van Tol
- Department of Biochemistry, Cardiovascular Research Institute COEUR, Erasmus University Rotterdam, Rotterdam, The Netherlands.
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Murdoch SJ, Wolfbauer G, Kennedy H, Marcovina SM, Carr MC, Albers JJ. Differences in reactivity of antibodies to active versus inactive PLTP significantly impacts PLTP measurement. J Lipid Res 2002. [DOI: 10.1016/s0022-2275(20)30170-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Huuskonen J, Olkkonen VM, Jauhiainen M, Ehnholm C. The impact of phospholipid transfer protein (PLTP) on HDL metabolism. Atherosclerosis 2001; 155:269-81. [PMID: 11254896 DOI: 10.1016/s0021-9150(01)00447-6] [Citation(s) in RCA: 166] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
High-density lipoproteins (HDL) play a major protective role against the development of coronary artery disease. Phospholipid transfer protein (PLTP) is a main factor regulating the size and composition of HDL in the circulation and plays an important role in controlling plasma HDL levels. This is achieved via both the phospholipid transfer activity of PLTP and its capability to cause HDL conversion. The present review focuses on the impact of PLTP on HDL metabolism. The basic characteristics and structure of the PLTP protein are described. The two main functions of PLTP, PLTP-mediated phospholipid transfer and HDL conversion are reviewed, and the mechanisms and control, as well as the physiological significance of these processes are discussed. The relationship between PLTP and the related cholesteryl ester transfer protein (CETP) is reviewed. Thereafter other functions of PLTP are recapitulated: the ability of PLTP to transfer cholesterol, alpha-tocopherol and lipopolysaccharide (LPS), and the suggested involvement of PLTP in cellular cholesterol traffic. The discussion on PLTP activity and mass in (patho)physiological settings includes new data on the presence of two forms of PLTP in the circulation, one catalytically active and the other inactive. Finally, future directions for PLTP research are outlined.
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Affiliation(s)
- J Huuskonen
- Department of Biochemistry, National Public Health Institute, Mannerheimintie 166, 00300, Helsinki, Finland
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Oka T, Kujiraoka T, Ito M, Egashira T, Takahashi S, Nanjee MN, Miller NE, Metso J, Olkkonen VM, Ehnholm C, Jauhiainen M, Hattori H. Distribution of phospholipid transfer protein in human plasma: presence of two forms of phospholipid transfer protein, one catalytically active and the other inactive. J Lipid Res 2000. [DOI: 10.1016/s0022-2275(20)31998-2] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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