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Li ZM, Miller M, Gachkar S, Mittag J, Schriever SC, Pfluger PT, Schramm KW, De Angelis M. Determination of 3-iodothyronamine (3-T 1AM) in mouse liver using liquid chromatography-tandem mass spectrometry. J Chromatogr B Analyt Technol Biomed Life Sci 2021; 1165:122553. [PMID: 33503577 DOI: 10.1016/j.jchromb.2021.122553] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2020] [Revised: 12/09/2020] [Accepted: 01/12/2021] [Indexed: 10/22/2022]
Abstract
3-iodothyronamine (3-T1AM) has been suggested as a novel chemical messenger and potent trace amine-associated receptor 1 ligand in the CNS that occurs naturally as endogenous metabolite of the thyroid hormones. Discrepancies and variations in 3-T1AM plasma and tissue concentrations have nonetheless caused controversy regarding the existence and biological role of 3-T1AM. These discussions are at least partially based on potential analytical artefacts caused by differential decay kinetics of 3-T1AM and the widely used deuterated quantification standard D4-T1AM. Here, we report a novel LC-MS/MS method for the quantification of 3-T1AM in biological specimens using stable isotope dilution with 13C6-T1AM, a new internal standard that showed pharmacodynamic properties comparable to endogenous 3-T1AM. The method detection limit (MDL) and method quantification limit (MQL) of 3-T1AM were 0.04 and 0.09 ng/g, respectively. The spike-recoveries of 3-T1AM were between 85.4% and 94.3%, with a coefficient of variation of 3.7-5.8%. The intra-day and inter-day variations of 3-T1AM were 8.45-11.2% and 3.58-5.73%, respectively. Endogenous 3-T1AM liver values in C57BL/6J mice were 2.20 ± 0.49 pmol/g with a detection frequency of 50%. Higher liver 3-T1AM values were found when C57BL/6J mice were treated with N-acetyl-3-iodothyronamine or O-acetyl-3-iodothyronamine. Overall, our new stable isotope dilution LC-MS/MS method improves both the sensitivity and selectivity compared with existing methods. The concomitant possibility to quantify additional thyroid hormones such as thyroxine, 3,5,3'-triiodo-L-thyronine, 3,3',5'-triiodo-L-thyronine, 3,3'-diiodo-L-thyronine, and 3,5-diiodo-L-thyronine further adds to the value of our novel method in exploring the natural occurrence and fate of 3-T1AM in biological tissues and fluids.
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Affiliation(s)
- Zhong-Min Li
- Helmholtz Zentrum München-German Research Center for Environmental Health (GmbH), Molecular EXposomics, Ingolstädter Landstr. 1, 85764 Neuherberg, Germany; School of Life Sciences Weihenstephan (Nutrition), Technical University Munich, 85354 Freising, Germany.
| | - Manuel Miller
- Helmholtz Zentrum München-German Research Center for Environmental Health (GmbH), Research Unit Comparative Medicine (AVM), Ingolstädter Landstr. 1, 85764 Neuherberg, Germany
| | - Sogol Gachkar
- Institute for Endocrinology & Diabetes, Molecular Endocrinology, Center of Brain, Behavior & Metabolism, University of Lübeck, Lübeck, Germany
| | - Jens Mittag
- Institute for Endocrinology & Diabetes, Molecular Endocrinology, Center of Brain, Behavior & Metabolism, University of Lübeck, Lübeck, Germany
| | - Sonja C Schriever
- German Center for Diabetes Research (DZD), Neuherberg, Germany; Institute for Diabetes and Obesity, Helmholtz Diabetes Center at Helmholtz Zentrum München, Germany; Research Unit Neurobiology of Diabetes, Helmholtz Zentrum München, Neuherberg, Germany
| | - Paul T Pfluger
- German Center for Diabetes Research (DZD), Neuherberg, Germany; Institute for Diabetes and Obesity, Helmholtz Diabetes Center at Helmholtz Zentrum München, Germany; Research Unit Neurobiology of Diabetes, Helmholtz Zentrum München, Neuherberg, Germany; TUM School of Medicine, Neurobiology of Diabetes, Technical University Munich, Germany
| | - Karl-Werner Schramm
- Helmholtz Zentrum München-German Research Center for Environmental Health (GmbH), Molecular EXposomics, Ingolstädter Landstr. 1, 85764 Neuherberg, Germany; Department für Biowissenschaftliche Grundlagen, Technische Universität München, Weihenstephaner Steig 23, 85350 Freising, Germany
| | - Meri De Angelis
- Helmholtz Zentrum München-German Research Center for Environmental Health (GmbH), Molecular EXposomics, Ingolstädter Landstr. 1, 85764 Neuherberg, Germany
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Ferchaud-Roucher V, Zair Y, Aguesse A, Krempf M, Ouguerram K. Omega 3 Improves Both apoB100-containing Lipoprotein Turnover and their Sphingolipid Profile in Hypertriglyceridemia. J Clin Endocrinol Metab 2020; 105:5893579. [PMID: 32805740 DOI: 10.1210/clinem/dgaa459] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Accepted: 08/08/2020] [Indexed: 01/17/2023]
Abstract
CONTEXT Evidence for an association between sphingolipids and metabolic disorders is increasingly reported. Omega-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFAs) improve apolipoprotein B100 (apoB100)-containing lipoprotein metabolism, but their effects on the sphingolipid content in lipoproteins remain unknown. OBJECTIVES In subjects with hypertriglyceridemia, we analyzed the effect of n-3 LC-PUFAs on the turnover apoB100-containing lipoproteins and on their sphingolipid content and looked for the possible association between these lipid levels and apoB100-containing lipoprotein turnover parameters. METHODS Six subjects underwent a kinetic study before and after n-3 supplementation for 2 months with 1 g of fish oil 3 times day containing 360 mg of eicosapentaenoic acid (EPA) and 240 mg of docosahexaenoic acid (DHA) in the form of triglycerides. We examined apoB100-containing lipoprotein turnover by primed perfusion labeled [5,5,5-2H3]-leucine and determined kinetic parameters using a multicompartmental model. We quantified sphingolipid species content in lipoproteins using mass spectrometry. RESULTS Supplementation decreased very low-density lipoprotein (VLDL), triglyceride, and apoB100 concentrations. The VLDL neutral and polar lipids showed increased n-3 LC-PUFA and decreased n-6 LC-PUFA content. The conversion rate of VLDL1 to VLDL2 and of VLDL2 to LDL was increased. We measured a decrease in total apoB100 production and VLDL1 production. Supplementation reduced the total ceramide concentration in VLDL while the sphingomyelin content in LDL was increased. We found positive correlations between plasma palmitic acid and VLDL ceramide and between VLDL triglyceride and VLDL ceramide, and inverse correlations between VLDL n-3 LC-PUFA and VLDL production. CONCLUSION Based on these results, we hypothesize that the improvement in apoB100 metabolism during n-3 LC-PUFA supplementation is contributed to by changes in sphingolipids.
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Affiliation(s)
- Véronique Ferchaud-Roucher
- University of Nantes, CHU Nantes, INRAe, UMR 1280 Physiopathology of Nutritional Adaptations, Nantes, France
- CRNH, West Human Nutrition Research Center, Nantes, France
| | - Yassine Zair
- CRNH, West Human Nutrition Research Center, Nantes, France
| | - Audrey Aguesse
- University of Nantes, CHU Nantes, INRAe, UMR 1280 Physiopathology of Nutritional Adaptations, Nantes, France
- CRNH, West Human Nutrition Research Center, Nantes, France
| | - Michel Krempf
- University of Nantes, CHU Nantes, INRAe, UMR 1280 Physiopathology of Nutritional Adaptations, Nantes, France
- CRNH, West Human Nutrition Research Center, Nantes, France
| | - Khadija Ouguerram
- University of Nantes, CHU Nantes, INRAe, UMR 1280 Physiopathology of Nutritional Adaptations, Nantes, France
- CRNH, West Human Nutrition Research Center, Nantes, France
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Chétiveaux M, Croyal M, Ouguerram K, Fall F, Flet L, Zair Y, Nobecourt E, Krempf M. Effect of fasting and feeding on apolipoprotein A-I kinetics in preβ 1-HDL, α-HDL, and triglyceride-rich lipoproteins. Sci Rep 2020; 10:15585. [PMID: 32973209 PMCID: PMC7519065 DOI: 10.1038/s41598-020-72323-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Accepted: 08/03/2020] [Indexed: 11/24/2022] Open
Abstract
The aim of this study was to compare the kinetics of apolipoprotein (apo)A-I during fed and fasted states in humans, and to determine to what extent the intestine contributes to apoA-I production. A stable isotope study was conducted to determine the kinetics of apoA-I in preβ1 high-density lipoprotein (HDL) and α-HDL. Six healthy male subjects received a constant intravenous infusion of 2H3-leucine for 14 h. Subjects in the fed group also received small hourly meals. Blood samples were collected hourly during tracer infusion and then daily for 4 days. Tracer enrichments were measured by mass spectrometry and then fitted to a compartmental model using asymptotic plateau of very-low-density lipoprotein (VLDL) apoB100 and triglyceride-rich lipoprotein (TRL) apoB48 as estimates of hepatic and intestinal precursor pools, respectively. The clearance rate of preβ1-HDL-apoA-I was lower in fed individuals compared with fasted subjects (p < 0.05). No other differences in apoA-I production or clearance rates were observed between the groups. No significant correlation was observed between plasma apoC-III concentrations and apoA-I kinetic data. In contrast, HDL-apoC-III was inversely correlated with the conversion of α-HDL to preβ1-HDL. Total apoA-I synthesis was not significantly increased in fed subjects. Hepatic production was not significantly different between the fed group (17.17 ± 2.75 mg/kg/day) and the fasted group (18.67 ± 1.69 mg/kg/day). Increase in intestinal apoA-I secretion in fed subjects was 2.20 ± 0.61 mg/kg/day. The HDL-apoA-I kinetics were similar in the fasted and fed groups, with 13% of the total apoA-I originating from the intestine with feeding.
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Affiliation(s)
| | - Mikaël Croyal
- CRNH-O Mass Spectrometry Core Facility, Nantes, France. .,NUN, INRA, CHU Nantes, UMR 1280, PhAN, IMAD, CRNH-O, IRS-UN-Spectrométrie de Masse-8, quai Moncousu, 44000, Nantes, France.
| | - Khadija Ouguerram
- CRNH-O Mass Spectrometry Core Facility, Nantes, France.,NUN, INRA, CHU Nantes, UMR 1280, PhAN, IMAD, CRNH-O, IRS-UN-Spectrométrie de Masse-8, quai Moncousu, 44000, Nantes, France
| | - Fanta Fall
- CRNH-O Mass Spectrometry Core Facility, Nantes, France
| | - Laurent Flet
- Pharmacy Department, Nantes University Hospital, Nantes, France
| | - Yassine Zair
- CRNH-O Mass Spectrometry Core Facility, Nantes, France
| | - Estelle Nobecourt
- CRNH-O Mass Spectrometry Core Facility, Nantes, France.,Nephrology Department, CHU Saint-Pierre, La Réunion, France
| | - Michel Krempf
- CRNH-O Mass Spectrometry Core Facility, Nantes, France.,Clinique Bretéché, Groupe Elsan, Nantes, France
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Update on the laboratory investigation of dyslipidemias. Clin Chim Acta 2018; 479:103-125. [PMID: 29336935 DOI: 10.1016/j.cca.2018.01.015] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Revised: 01/03/2018] [Accepted: 01/09/2018] [Indexed: 01/08/2023]
Abstract
The role of the clinical laboratory is evolving to provide more information to clinicians to assess cardiovascular disease (CVD) risk and target therapy more effectively. Current routine methods to measure LDL-cholesterol (LDL-C), the Friedewald calculation, ultracentrifugation, electrophoresis and homogeneous direct methods have established limitations. Studies suggest that LDL and HDL size or particle concentration are alternative methods to predict future CVD risk. At this time there is no consensus role for lipoprotein particle or subclasses in CVD risk assessment. LDL and HDL particle concentration are measured by several methods, namely gradient gel electrophoresis, ultracentrifugation-vertical auto profile, nuclear magnetic resonance and ion mobility. It has been suggested that HDL functional assays may be better predictors of CVD risk. To assess the issue of lipoprotein subclasses/particles and HDL function as potential CVD risk markers robust, simple, validated analytical methods are required. In patients with small dense LDL particles, even a perfect measure of LDL-C will not reflect LDL particle concentration. Non-HDL-C is an alternative measurement and includes VLDL and CM remnant cholesterol and LDL-C. However, apolipoprotein B measurement may more accurately reflect LDL particle numbers. Non-fasting lipid measurements have many practical advantages. Defining thresholds for treatment with new measurements of CVD risk remain a challenge. In families with genetic variants, ApoCIII and lipoprotein (a) may be additional risk factors. Recognition of familial causes of dyslipidemias and diagnosis in childhood will result in early treatment. This review discusses the limitations in current laboratory technologies to predict CVD risk and reviews the evidence for emergent approaches using newer biomarkers in clinical practice.
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Janssen ST, Janssen OE. Directional thyroid hormone distribution via the blood stream to target sites. Mol Cell Endocrinol 2017; 458:16-21. [PMID: 28257828 DOI: 10.1016/j.mce.2017.02.037] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Revised: 02/23/2017] [Accepted: 02/23/2017] [Indexed: 12/19/2022]
Abstract
Thyroid hormones are bound to three major serum transport proteins, thyroxin-binding globulin (TBG), transthyretin (TTR) and human serum albumin (HSA). TBG has the strongest affinity for thyroid hormones, TTR is also found in the cerebrospinal fluid and HSA is the most abundant protein in plasma. Combination defects of either a high affinity TTR or HSA variant do not compensate TBG deficiency, underscoring the dominant role of TBG among the thyroid hormone transport proteins. On the other hand, coexistence of raised affinity TTR and HSA variants causes an augmented hyperthyroxinemia. Variations in thyroid hormone transport proteins may alter thyroid function tests to mimic hypo- or hyperthyroidism. As affected individuals are clinically euthyroid and do not require treatment, identification of thyroid hormone transport protein defects is important to avoid unnecessary diagnostic and therapeutic interventions. Mammals share the multilayered system of thyroid hormone binding proteins with humans. Some of them, especially carnivores, do not express TBG. In dogs, this defect has been shown to be caused by a defective hepatocyte nuclear factor-1 binding site in the TBG promoter, preventing TBG synthesis in the liver. The major endogenous thyroid hormone metabolite 3-iodothyronamine (3-T1AM) exerts marked cryogenic, metabolic, cardiac and central nervous system actions. It is bound to apolipoproteinB-100 (ApoB100), possibly facilitating its cellular uptake via interaction with the low density lipoprotein-receptor. This review summarizes the handling of hydrophobic charged thyroid hormone signaling molecules and their metabolite 3-T1AM in aqueous body fluids and the advantages and limits of their serum distributor proteins.
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Affiliation(s)
- Susanne T Janssen
- Institute of Laboratory Medicine, AescuLabor Hamburg, Hamburg, Germany
| | - Onno E Janssen
- Department of Internal Medicine, Endokrinologikum Hamburg, Hamburg, Germany.
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Hoefig CS, Zucchi R, Köhrle J. Thyronamines and Derivatives: Physiological Relevance, Pharmacological Actions, and Future Research Directions. Thyroid 2016; 26:1656-1673. [PMID: 27650974 DOI: 10.1089/thy.2016.0178] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Thyronamines (3-T1AM, T0AM) are endogenous compounds probably derived from L-thyroxine or its intermediate metabolites. Combined activities of intestinal deiodinases and ornithine decarboxylase generate 3-T1AM in vitro. Alternatively, 3-T1AM might be formed by the thyroid gland and secreted into the blood. 3-T1AM and T0AM concentrations have been determined by liquid chromatography-tandem mass spectrometry analysis (LC-MS/MS) in tissues, serum, and cell lines. However, large variations of 3-T1AM concentrations in human serum were reported by LC-MS/MS compared with a monoclonal antibody-based immunoassay. These differences might be caused by strong binding of the highly hydrophobic 3-T1AM to apolipoprotein B100. Pharmacological administration of 3-T1AM results in dose-dependent reversible effects on body temperature, cardiac function, energy metabolism, and neurological functions. The physiological relevance of these actions is unclear, but may occur at tissue concentrations close to the estimated endogenous concentrations of 3-T1AM or its metabolites T0AM or thyroacetic acid (TA1). A number of putative receptors, binding sites, and cellular target molecules mediating actions of the multi-target ligand 3-T1AM have been proposed. Among those are members of the trace amine associated receptor family, the adrenergic receptor ADRα2a, and the thermosensitive transient receptor potential melastatin 8 channel. Preclinical studies employing various animal experimental models are in progress, and more stable receptor-selective agonistic and antagonistic analogues of 3-T1AM are now available for testing. The potent endogenous thyroid hormone-derived biogenic amine 3-T1AM exerts marked cryogenic, metabolic, cardiac and central actions and represents a valuable lead compound linking endocrine, metabolic, and neuroscience research to advance development of new drugs.
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Affiliation(s)
- Carolin Stephanie Hoefig
- 1 Institut für Experimentelle Endokrinologie Charité, Universitätsmedizin Berlin , Berlin, Germany
| | - Riccardo Zucchi
- 2 Laboratory of Biochemistry, Department of Pathology, University of Pisa , Pisa, Italy
| | - Josef Köhrle
- 1 Institut für Experimentelle Endokrinologie Charité, Universitätsmedizin Berlin , Berlin, Germany
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Croyal M, Fall F, Ferchaud-Roucher V, Chétiveaux M, Zaïr Y, Ouguerram K, Krempf M, Nobécourt E. Multiplexed peptide analysis for kinetic measurements of major human apolipoproteins by LC/MS/MS. J Lipid Res 2016; 57:509-15. [PMID: 26773160 DOI: 10.1194/jlr.d064618] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2015] [Indexed: 11/20/2022] Open
Abstract
A multiplexed assay was developed by MS to analyze, in a single run, six major human Apos involved in lipoprotein metabolism: ApoA-I, ApoA-II, ApoB100, ApoC-II, ApoC-III, and ApoE. This method was validated in vivo in six subjects who received a 14 h constant infusion of [5,5,5-(2)H3]L-leucine at 10 μM/kg/h. Plasma lipoprotein fractions were isolated from collected blood samples and were digested with trypsin. Proteotypic peptides were subsequently analyzed by LC/MS/MS. Enrichment measurement data were compared with those obtained by the standard method using GC/MS. The required time to obtain the LC/MS/MS data was less than that needed for GC/MS. The enrichments from both methods were correlated for ApoA-I (r = 0.994; P < 0.0001) and ApoB100 (r = 0.999; P < 0.0001), and the Bland-Altman plot confirmed the similarity of the two methods. Intra- and inter-assay variability calculated for the six Apos of interest did not exceed 10.7 and 12.5%, respectively, and kinetic parameters were similar and/or in agreement with previously reported data. Therefore, LC/MS/MS can be considered as a useful tool for human Apo kinetic studies using stable isotopes.
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Affiliation(s)
- Mikaël Croyal
- INRA, UMR 1280, Physiologie des Adaptations Nutritionnelles, CHU Hôtel-Dieu, F-44000 Nantes, France CRNHO, West Human Nutrition Research Center, CHU, F-44093 Nantes, France
| | - Fanta Fall
- INRA, UMR 1280, Physiologie des Adaptations Nutritionnelles, CHU Hôtel-Dieu, F-44000 Nantes, France CRNHO, West Human Nutrition Research Center, CHU, F-44093 Nantes, France
| | - Véronique Ferchaud-Roucher
- INRA, UMR 1280, Physiologie des Adaptations Nutritionnelles, CHU Hôtel-Dieu, F-44000 Nantes, France CRNHO, West Human Nutrition Research Center, CHU, F-44093 Nantes, France
| | - Maud Chétiveaux
- CRNHO, West Human Nutrition Research Center, CHU, F-44093 Nantes, France
| | - Yassine Zaïr
- CRNHO, West Human Nutrition Research Center, CHU, F-44093 Nantes, France
| | - Khadija Ouguerram
- INRA, UMR 1280, Physiologie des Adaptations Nutritionnelles, CHU Hôtel-Dieu, F-44000 Nantes, France CRNHO, West Human Nutrition Research Center, CHU, F-44093 Nantes, France
| | - Michel Krempf
- INRA, UMR 1280, Physiologie des Adaptations Nutritionnelles, CHU Hôtel-Dieu, F-44000 Nantes, France CRNHO, West Human Nutrition Research Center, CHU, F-44093 Nantes, France Department of Endocrinology, Metabolic Diseases, and Nutrition, G and R Laennec Hospital, F-44093 Nantes, France
| | - Estelle Nobécourt
- INRA, UMR 1280, Physiologie des Adaptations Nutritionnelles, CHU Hôtel-Dieu, F-44000 Nantes, France CRNHO, West Human Nutrition Research Center, CHU, F-44093 Nantes, France Department of Endocrinology, Metabolic Diseases, and Nutrition, G and R Laennec Hospital, F-44093 Nantes, France
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Chan DC, Gan SK, Wong ATY, Barrett PHR, Watts GF. Association between skeletal muscle fat content and very-low-density lipoprotein-apolipoprotein B-100 transport in obesity: effect of weight loss. Diabetes Obes Metab 2014; 16:994-1000. [PMID: 24821431 DOI: 10.1111/dom.12311] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2014] [Revised: 04/10/2014] [Accepted: 05/02/2014] [Indexed: 11/27/2022]
Abstract
AIMS Ectopic deposition of fat in skeletal muscle is a feature of metabolic syndrome, but its specific association with very-low-density lipoprotein (VLDL)-apolipoprotein (apo) B-100 metabolism remains unclear. METHODS We examined the association between skeletal muscle fat content and VLDL-apoB-100 kinetics in 25 obese subjects, and the responses of these variables to weight loss. The fat contents of liver, abdomen and skeletal muscle were determined by magnetic resonance imaging, and VLDL-apoB-100 kinetics were assessed using stable isotope tracers. RESULTS In obese subjects who were insulin sensitive (homeostasis model assessment, HOMA, score ≤ 2.6, n = 12), skeletal muscle fat content was significantly associated with hepatic fat content (r = 0.636), energy intake (r = 0.694), plasma triglyceride (r = 0.644), apoB-100 (r = 0.529), glucose (r = 0.622), VLDL-apoB-100 concentrations (r = 0.860), VLDL-apoB-100 fractional catabolic rate (FCR; r = -0.581) and VLDL-apoB-100 secretion rate (r = 0.607). These associations were not found in obese subjects who were insulin resistant (HOMA score >2.6, n = 13). Of these 25 subjects, 10 obese subjects underwent a 16-week weight loss program. The low-fat diet achieved significant reduction (p < 0.05) in body weight, visceral and subcutaneous fat areas, liver and skeletal muscle fat, energy intake, triglyceride, insulin, HOMA score, VLDL-apoB100 concentrations and VLDL-apoB100 secretion rate. The percentage reduction of skeletal muscle fat with weight loss was significantly associated with the corresponding changes in VLDL-apoB100 concentration (r = 0.770, p = 0.009) and VLDL-apoB-100 secretion (r = 0.682, p = 0.030). CONCLUSIONS Skeletal muscle fat content is associated with VLDL-apoB-100 transport. Weight loss lowers skeletal muscle fat and VLDL-apoB-100 secretion.
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Affiliation(s)
- D C Chan
- Metabolic Research Centre, School of Medicine and Pharmacology, University of Western Australia, Perth, Australia
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Schwaiger JP, Nakada Y, Berberich R, Ikewaki K, Dieplinger B, Zitt E, Neyer U, Salmhofer H, Kronenberg F, Koenig P, Dieplinger H. Lipoprotein kinetics in male hemodialysis patients treated with atorvastatin. Clin J Am Soc Nephrol 2013; 8:1319-26. [PMID: 23599405 DOI: 10.2215/cjn.10881012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
BACKGROUND AND OBJECTIVES In vivo metabolism of atherogenic apolipoprotein B (apoB)-containing lipoproteins is severely impaired in patients undergoing hemodialysis (HD), resulting in markedly prolonged residence times of these particles. It is unclear whether treatment with statins improves LDL kinetics in HD patients as is known for the general population. Therefore, this kinetic study assessed apoB-containing lipoproteins in these patients. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS Kinetic measures were analyzed with stable-isotope technology in six men undergoing HD before and after 3 months of daily administration of 10 mg of atorvastatin. Patients were 18-65 years of age, had LDL cholesterol levels between 90 and 200 mg/dl, and had been treated with HD for >6 months. They consumed a standardized isocaloric diet for 3 days before analysis. Fractional catabolic rates (FCRs) and production rates of very-low-density lipoprotein (VLDL)-apoB, intermediate-density lipoprotein-apoB, and LDL-apoB were determined using multicompartment modeling after plasma lipoprotein separation, precipitation of apoB, and determination of tracer-to-tracee ratios using mass spectrometry. RESULTS Plasma concentrations of VLDL- and LDL-apoB were significantly lower (mean ± SD, 7.77±2.62 versus 11.27±6.15 mg/dl, P<0.05; 56.9±23.9 versus 84.0±21.1 mg/dl, P=0.03) and their FCRs were significantly higher (7.20±3.08 versus 5.20±2.98 days(-1), P<0.05; 0.851±0.772 versus 0.446±0.232 days(-1), P<0.05) after 3 months of atorvastatin treatment. Accordingly, the residence times in plasma of VLDL- and LDL-apoB were significantly lower after treatment (0.14 versus 0.19 day and 1.2 versus 2.2 days, respectively). CONCLUSION Lower plasma concentrations and improved kinetics of atherogenic lipoproteins were observed in HD patients after administration of low-dose atorvastatin.
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Affiliation(s)
- Johannes P Schwaiger
- Division of Genetic Epidemiology, Department of Medical Genetics and Molecular Pharmacology, Innsbruck Medical University, Innsbruck, Austria
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10
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Chan DC, Hoang A, Barrett PHR, Wong ATY, Nestel PJ, Sviridov D, Watts GF. Apolipoprotein B-100 and apoA-II kinetics as determinants of cellular cholesterol efflux. J Clin Endocrinol Metab 2012; 97:E1658-66. [PMID: 22745238 DOI: 10.1210/jc.2012-1522] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
CONTEXT Cellular cholesterol efflux is a key step in reverse cholesterol transport and may depend on the metabolism of apolipoprotein (apo) B-100, apoA-I, and apoA-II. OBJECTIVE We examined the associations between cholesterol efflux and plasma concentrations and kinetics of very low-density lipoprotein (VLDL), intermediate-density lipoprotein (IDL), and low-density lipoprotein (LDL)-apoB-100, high-density lipoprotein (HDL)-apoA-I, and HDL-apoA-II in men. DESIGN, SUBJECTS, AND METHODS: Thirty men were recruited from the community with a wide range of body mass index. The capacity of plasma and HDL to efflux cholesterol was measured ex vivo. Apolipoprotein kinetics were measured using stable isotope techniques and multicompartmental modeling. RESULTS Cholesterol efflux to whole plasma was correlated with plasma levels of cholesterol, triglyceride, apoB-100, insulin, cholesteryl ester transfer protein, and lecithin-cholesterol acyltransferase, body mass index and waist circumference (P < 0.05 in all). Cholesterol efflux was inversely correlated with the fractional catabolic rate (FCR) of VLDL (r = -0.728), IDL (r = -0.662), and LDL-apoB-100 (r = -0.479) but positively correlated with the FCR (r = 0.438) and production rate (r = 0.468) of HDL-apoA-II. In multiple regression analysis, the concentration and FCR of VLDL-apoB-100 (β-coefficient = 0.708 and -0.518, respectively) and IDL-apoB-100 (β-coefficient = 0.354 and -0.447, respectively) were independent predictors of cholesterol efflux. The association of cholesterol efflux with apoB-100 metabolism was diminished after removal of apoB-100-containing lipoproteins from plasma prior to efflux. All associations, except for cholesteryl ester transfer protein, were lost when cholesterol efflux to isolated HDL was tested. CONCLUSIONS The plasma concentration and kinetics of apoB-100-containing lipoproteins are significant predictors of the capacity of whole plasma to effect cellular cholesterol efflux.
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Affiliation(s)
- Dick C Chan
- School of Medicine and Pharmacology, University of Western Australia, Royal Perth Hospital, G.P.O. Box X2213, Perth, Western Australia 6847, Australia
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Roy G, Placzek E, Scanlan TS. ApoB-100-containing lipoproteins are major carriers of 3-iodothyronamine in circulation. J Biol Chem 2011; 287:1790-800. [PMID: 22128163 DOI: 10.1074/jbc.m111.275552] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
3-Iodothyronamine (T(1)AM) is a biogenic amine derivative of thyroid hormone present in tissue and blood of vertebrates. Approximately 99% of the circulating thyroid hormones are bound to plasma proteins, including three major thyroid hormone-binding proteins, and the question arises as to whether circulating T(1)AM is also bound to serum factors. We report here that T(1)AM is largely bound to a single protein component of human serum. Using T(1)AM-affinity chromatography, we isolated this protein, and sequence analysis identified it as apolipoprotein B-100 (apoB-100), the protein component of several low density lipoprotein particles. Consistent with this finding, we demonstrate that >90% of specifically bound T(1)AM in human serum resides in the apoB-100-containing low density lipoprotein fraction. T(1)AM reversibly binds to apoB-100-containing lipoprotein particles with an equilibrium dissociation constant (K(D)) of 17 nm and a T(1)AM/apoB-100 stoichiometry of 1:1. Competition binding assays demonstrate that this binding site is highly selective for T(1)AM. Intracellular T(1)AM uptake is significantly enhanced by apoB-100-containing lipoprotein particles. Modest enhancements to apoB-100 cellular uptake and secretion by T(1)AM were observed; however, multidose T(1)AM treatment did not affect lipid or lipoprotein inventory in vivo. Thus, it appears that apoB-100 serves as a carrier of circulating T(1)AM and affords a novel mechanism by which T(1)AM gains entry to cells.
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Affiliation(s)
- Gouriprassana Roy
- Department of Physiology and Pharmacology, Oregon Health and Science University, Portland, Oregon 97239-3098, USA
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Chan DC, Watts GF, Gan SK, Ooi EMM, Barrett PHR. Effect of ezetimibe on hepatic fat, inflammatory markers, and apolipoprotein B-100 kinetics in insulin-resistant obese subjects on a weight loss diet. Diabetes Care 2010; 33:1134-9. [PMID: 20185740 PMCID: PMC2858190 DOI: 10.2337/dc09-1765] [Citation(s) in RCA: 130] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE Nonalcoholic fatty liver disease is highly prevalent in obese and type 2 diabetic individuals and is strongly associated with dyslipidemia and inflammation. Weight loss and/or pharmacotherapy are commonly used to correct these abnormalities. RESEARCH DESIGN AND METHODS We performed a 16-week intervention trial of a hypocaloric, low-fat diet plus 10 mg/day ezetimibe (n = 15) versus a hypocaloric, low-fat diet alone (n = 10) on intrahepatic triglyceride (IHTG) content, plasma high sensitivity-C-reactive protein (hs-CRP), adipocytokines, and fetuin-A concentrations and apolipoprotein (apo)B-100 kinetics in obese subjects. ApoB-100 metabolism was assessed using stable isotope tracer kinetics and compartmental modeling; liver and abdominal fat contents were determined by magnetic resonance techniques. RESULTS Both weight loss and ezetimibe plus weight loss significantly (all P < 0.05) reduced body weight, visceral and subcutaneous adipose tissues, insulin resistance and plasma triglycerides, VLDL-apoB-100, apoC-III, fetuin-A, and retinol-binding protein-4 and increased plasma adiponectin concentrations. Compared with weight loss alone, ezetimibe plus weight loss significantly (all P < 0.05) decreased IHTG content (-18%), plasma hs-CRP (-53%), interleukin-6 (-24%), LDL cholesterol (-18%), campesterol (-59%), and apoB-100 (-14%) levels, with a significant increase in plasma lathosterol concentrations (+43%). The LDL-apoB-100 concentration also significantly fell with ezetimibe plus weight loss (-12%), chiefly owing to an increase in the corresponding fractional catabolic rate (+29%). The VLDL-apoB-100 secretion rate fell with both interventions, with no significant independent effect of ezetimibe. CONCLUSIONS Addition of ezetimibe to a moderate weight loss diet in obese subjects can significantly improve hepatic steatosis, inflammation, and LDL-apoB-100 metabolism.
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Affiliation(s)
- Dick C Chan
- Metabolic Research Centre, School of Medicine and Pharmacology, University of Western Australia, Perth, Western Australia, Australia
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Chan DC, Watts GF, Gan S, Wong ATY, Ooi EMM, Barrett PHR. Nonalcoholic fatty liver disease as the transducer of hepatic oversecretion of very-low-density lipoprotein-apolipoprotein B-100 in obesity. Arterioscler Thromb Vasc Biol 2010; 30:1043-50. [PMID: 20150556 DOI: 10.1161/atvbaha.109.202275] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
OBJECTIVE To examine the association between liver fat content and very low-density lipoprotein (VLDL)-apolipoprotein (apo) B-100 kinetics and the corresponding responses to weight loss in obese subjects. METHODS AND RESULTS VLDL-apoB-100 kinetics were assessed using stable isotope tracers, and the fat content of the liver and abdomen was determined by magnetic resonance techniques in 25 obese subjects. In univariate analysis, liver fat content was significantly (P<0.05 in all) associated with body mass index (r=0.65), visceral fat area (r=0.45), triglycerides (r=0.40), homeostasis model assessment score (r=0.40), VLDL-apoB-100 concentrations (r=0.44), and secretion rate (r=0.45). However, liver fat content was not associated with plasma concentrations of retinol-binding protein 4, fetuin A, adiponectin, interleukin-6, and tumor necrosis factor-alpha. Of these 25 subjects, 9 diagnosed as having nonalcoholic fatty liver disease (which is highly prevalent in obese individuals and strongly associated with dyslipidemia) underwent a weight loss program. The low-fat diet achieved significant reduction in body weight, body mass index, liver fat, visceral and subcutaneous fat areas, homeostasis model assessment score, triglycerides, VLDL-apoB-100 concentrations, and VLDL-apoB-100 secretion rate. The percentage reduction of liver fat with weight loss was significantly associated with the corresponding decreases in VLDL-apoB-100 secretion (r=0.67) and visceral fat (r=0.84). CONCLUSION In patients with obesity, hepatic steatosis increases VLDL-apoB-100 secretion. Weight loss can help reduce this abnormality.
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Affiliation(s)
- Dick C Chan
- Metabolic Research Centre, School of Medicine and Pharmacology, University of Western Australia, Perth, Australia
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14
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Grundy SM, Vega GL, Tomassini JE, Tershakovec AM. Correlation of non-high-density lipoprotein cholesterol and low-density lipoprotein cholesterol with apolipoprotein B during simvastatin + fenofibrate therapy in patients with combined hyperlipidemia (a subanalysis of the SAFARI trial). Am J Cardiol 2009; 104:548-53. [PMID: 19660610 DOI: 10.1016/j.amjcard.2009.04.018] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2008] [Revised: 04/08/2009] [Accepted: 04/08/2009] [Indexed: 10/20/2022]
Abstract
Guidelines have recommended non-high-density lipoprotein (non-HDL) cholesterol as a secondary target for therapy after the low-density lipoprotein (LDL) cholesterol goals have been met in patients with hypertriglyceridemia; non-HDL cholesterol is viewed as a surrogate for apolipoprotein (Apo)B, an alternate end point of treatment. The present analysis of the previously reported Simvastatin plus Fenofibrate for Combined Hyperlipidemia (SAFARI) trial assessed the associations of non-HDL cholesterol and LDL cholesterol with ApoB levels in patients with combined hyperlipidemia treated with combination simvastatin (20 mg) and fenofibrate (160 mg) or simvastatin monotherapy (20 mg). The correlations of these factors were analyzed in the overall modified intent-to-treat population (n = 594) and in patient subgroups stratified by triglyceride (TG) tertiles. Simvastatin plus fenofibrate and simvastatin alone significantly reduced LDL cholesterol, TG, non-HDL cholesterol and ApoB levels and non-HDL cholesterol/ApoB ratio (p < or =0.0004), regardless of the TG level. The greatest reductions occurred with combination treatment. The baseline levels of non-HDL cholesterol and LDL cholesterol correlated highly with ApoB and were stronger in the lower TG tertiles than in the higher TG tertiles. After 12 weeks, the correlations had changed little with simvastatin monotherapy but had increased substantially with combination therapy and were most improved at high TG levels. In conclusion, these results suggest that both non-HDL cholesterol and ApoB provide similar information in relation to treatment response in patients with combined hyperlipidemia and hypertriglyceridemia, and that non-HDL cholesterol is a good indicator of ApoB-containing lipoproteins, supporting its recommended use as a secondary therapeutic target in these patients.
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15
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Chan DT, Dogra GK, Irish AB, Ooi EM, Barrett PH, Chan DC, Watts GF. Chronic kidney disease delays VLDL-apoB-100 particle catabolism: potential role of apolipoprotein C-III. J Lipid Res 2009; 50:2524-31. [PMID: 19542564 DOI: 10.1194/jlr.p900003-jlr200] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
To determine the relative contribution of obesity and/or insulin resistance (IR) in the development of dyslipidemia in chronic kidney disease (CKD), we investigated the transport of apolipoprotein (apo) B-100 in nonobese, nondiabetic, nonnephrotic CKD subjects and healthy controls (HC). We determined total VLDL, VLDL(1), VLDL(2), intermediate density lipoprotein (IDL), and LDL-apoB-100 using intravenous D3-leucine, GC-MS, and multicompartmental modeling. Plasma apoC-III and apoB-48 were immunoassayed. In this case control study, we report higher plasma triglyceride, IDL-, VLDL-, VLDL(1)-, and VLDL(2)-apoB-100 concentrations in CKD compared with HC (P < 0.05). This was associated with decreased fractional catabolic rates [FCRs (pools/day)] [IDL:CKD 3.4 (1.6) vs. HC 5.0 (3.2), P < 0.0001; VLDL:CKD 4.8 (5.2) vs. HC 7.8 (4.8), P = 0.038; VLDL(1):CKD 10.1 (8.5) vs. HC 29.5 (45.1), P = 0.007; VLDL(2):CKD 5.4 (4.6) vs. HC 10.4 (3.4), P = 0.001] with no difference in production rates. Plasma apoC-III and apoB-48 were significantly higher in CKD (P < 0.001) and both correlated with impaired FCRs of VLDL, VLDL(1), and VLDL(2) apoB-100 (P < 0.05). In CKD, apoC-III concentration was the only independent predictor of clearance defects in VLDL and its subfractions. Moderate CKD in the absence of central adiposity and IR is associated with mild hypertriglyceridemia due to delayed catabolism of triglyceride rich lipoproteins, IDL, and VLDL, without changes in production rate. Altered apoC-III metabolism may contribute to dyslipidemia in CKD, and this requires further investigation.
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Affiliation(s)
- Doris T Chan
- School of Medicine Pharmacology, Royal Perth Hospital Unit, University of Western Australia, WA, Australia
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Briand F, Bailhache E, Andre A, Magot T, Krempf M, Nguyen P, Ouguerram K. The hyperenergetic-fed obese dog, a model of disturbance of apolipoprotein B-100 metabolism associated with insulin resistance: kinetic study using stable isotopes. Metabolism 2008; 57:966-72. [PMID: 18555839 DOI: 10.1016/j.metabol.2008.02.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2007] [Accepted: 02/15/2008] [Indexed: 01/18/2023]
Abstract
The hyperenergetic-fed beagle dog model of obesity-associated insulin resistance has previously demonstrated lipoprotein abnormalities similar to those of obese insulin-resistant humans. The aim of this study was to check, in the insulin-resistant dog, the mechanism leading to abnormalities in the mass of apolipoprotein B-100 (apo B-100) containing lipoproteins. Six healthy male beagle dogs were overfed with a high-fat diet for 28 +/- 2.5 weeks. Obesity was associated with insulin resistance as assessed by the euglycemic hyperinsulinemic clamp technique. The kinetics of very low-density lipoprotein (VLDL) and low-density lipoprotein (LDL) apo B-100 were recorded in dogs, at healthy and insulin-resistant states, using a primed constant infusion of [5,5,5-D(3)]leucine. Isotopic enrichment was measured by gas chromatography-mass spectrometry (GC-MS). A multicompartmental model was used for the analysis of tracer kinetics data. Apolipoprotein B-100 concentration was higher in VLDL (2.8-fold, P < .05) but lower in LDL (2-fold, P < .05) in the insulin-resistant compared to the healthy state. Kinetic analysis showed a higher VLDL apo B-100 production (1.7-fold, P < .05). The fractional catabolic rate of VLDL did not change significantly, but the lipolysis was decreased significantly (3-fold, P < .05). The lower LDL apo B-100 level in insulin-resistant dogs was explained by a higher LDL fractional catabolic rate (2.5-fold, P < .05). The mechanisms leading to hypertriglyceridemia (higher production rate and lower lipolysis of VLDL) in insulin-resistant dogs were similar to those described in the insulin-resistant humans.
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Affiliation(s)
- François Briand
- Centre de Recherche en Nutrition Humaine, Institut national de la santé et de la recherche médicale, INSERM U539, CHU Nantes F-44000, France
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17
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Ouguerram K, Maugeais C, Gardette J, Magot T, Krempf M. Effect of n-3 fatty acids on metabolism of apoB100-containing lipoprotein in type 2 diabetic subjects. Br J Nutr 2007; 96:100-6. [PMID: 16869997 DOI: 10.1079/bjn20061806] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The effect of long-chain n-3 PUFA on the metabolism of apoB100-containing lipoprotein in diabetic subjects is not fully understood. The objective of the present study was to determine the effect of a daily intake of 1080 mg EPA and 720 mg DHA for diabetic subjects on the kinetics of apoB100-containing lipoprotein in the fasting state. A kinetic study was undertaken to determine the mechanisms involved in the effects of n-3 fatty acids in terms of a decrease in triacylglycerol level in type 2 diabetic patients. We have studied the effect of fish oils on the metabolism of apoB100 endogenously labelled by [5,5,5-2H3]-leucine in type 2 diabetic patients in the fasting state. The kinetic parameters of apoB100 in VLDL, intermediate-density lipoprotein and LDL were determined by compartmental modelling in five diabetic subjects before and 8 weeks after n-3 fatty acid treatment. Treatment did not change the plasma cholesterol level (0.801 (sd 0.120) v. 0.793 (sd 0.163) mmol/l) but lowered the plasma triacylglycerol level (1.776 (sd 0.280) v.1.356 (sd 0.595) mmol/l; P < 0.05). Treated patients showed a decrease in VLDL apoB100 concentration (0.366 (sd 0.030) v.0.174 (sd 0.036) g/l; P < 0.05) related to a decrease in VLDL 1 production (1.49 (sd 0.23) v.0.44 (sd 0.19) mg/kg per h; P < 0.05) and an increase in the VLDL conversion rate (0.031 (sd 0.024) v.0.052 (sd 0.040) per h; P < 0.05), with no change in fractional catabolic rates. Treatment led to a higher direct production of intermediate-density lipoprotein (0.02 (sd 0.01) v.0.24 (sd 0.12) mg/kg per h; P < 0.05). In conclusion, the present study, conducted in the fasting state, showed that supplementation with n-3 fatty acids in type 2 diabetic patients induced beneficial changes in the metabolism of apoB100-containing lipoprotein.
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Bach-Ngohou K, Ouguerram K, Frénais R, Maugère P, Ripolles-Piquer B, Zaïr Y, Krempf M, Bard JM. Influence of atorvastatin on apolipoprotein E and AI kinetics in patients with type 2 diabetes. J Pharmacol Exp Ther 2005; 315:363-9. [PMID: 16014756 DOI: 10.1124/jpet.105.085522] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Atorvastatin reduces both plasma cholesterol and triglyceride concentrations in patients with type 2 diabetes, but mechanisms underlying triglyceride decrease and the effect of atorvastatin on high density lipoprotein (HDL) still remain unclear. Apolipoprotein (apo) E plays a crucial role in modulating production and clearance of triglyceride-rich very low density lipoprotein (VLDL). The main effect of apoAI is to modulate HDL metabolism. The aim of this work was to study the influence of atorvastatin on apoAI and apoE kinetics and to determine whether its hypocholesterolemic and hypotriglyceridemic effects could be related to changes in this apolipoprotein metabolism. Plasma VLDL-apoE, HDL-apoE, and HDL-apoAI were studied in seven patients with diabetes with mixed hyperlipidemia using a stable isotope labeling technique ([(2)H3]leucine-primed constant infusion) and monocompartmental model before and after 2 months of treatment with 40 mg/day of atorvastatin. Plasma apoE concentration was significantly reduced (44.1 +/- 19.1 versus 32 +/- 11.6 mg/l, p < 0.05) after treatment. This decrease was associated with a diminution of HDL-apoE concentration (17.46 +/- 6.71 versus 13.37 +/- 6.05 mg/l, p < 0.05) and production rate (0.202 +/- 0.085 versus 0.119 +/- 0.047 mg/kg/day, p < 0.05), whereas an increase in VLDL-apoE concentration (6.44 +/- 2.16 before versus 9.23 +/- 4.02 mg/l after, p < 0.05) and production rate (0.827 +/- 0.367 versus 1.524 +/- 0.664 mg/kg/day, p < 0.05) was observed. No significant difference was observed after treatment for apoAI parameters. We conclude that atorvastatin treatment promotes different apoE distribution between HDL and VLDL, favoring VLDL apoE content. The increased number of apoE per VLDL particle suggests that atorvastatin could enhance the direct catabolism of triglyceride-rich VLDL through apoE receptor pathways.
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Affiliation(s)
- K Bach-Ngohou
- Institut National de la Santé et de la Recherche Medicale U539, Centre de Recherche en Nutrition Humaine, CHU Hôtel-Dieu Nantes, France.
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Millar JS, Maugeais C, Ikewaki K, Kolansky DM, Barrett PHR, Budreck EC, Boston RC, Tada N, Mochizuki S, Defesche JC, Wilson JM, Rader DJ. Complete deficiency of the low-density lipoprotein receptor is associated with increased apolipoprotein B-100 production. Arterioscler Thromb Vasc Biol 2005; 25:560-5. [PMID: 15637307 DOI: 10.1161/01.atv.0000155323.18856.a2] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE We addressed the role of the low-density lipoprotein (LDL) receptor in determining clearance rates and production rate (PR) of apolipoprotein B (apoB) in humans. METHODS AND RESULTS Kinetic studies using endogenous labeling of apoB with deuterated leucine were performed in 7 genetically defined patients with homozygous familial hypercholesterolemia (FH) and compared with 4 controls. The fractional catabolic rates (FCR) and PRs for apoB were determined by multicompartmental modeling. The FCRs of very-low-density lipoprotein 1 (VLDL1), VLDL2, intermediate-density lipoprotein (IDL), and LDL apoB were lower in FH than in controls, with the LDL apoB FCR being significantly lower (0.148+/-0.049 versus 0.499+/-0.099 pools x d(-1); P=0.008). Whereas receptor-defective FH patients had a total apoB PR similar to controls, receptor-null FH patients had a significantly greater total apoB PR than controls (35.97+/-10.51 versus 21.32+/-4.21 mg x kg(-1) x d(-1), respectively; P=0.02). CONCLUSIONS This first study of apoB metabolism in homozygous FH using endogenous labeling with stable isotopes demonstrates that the LDL receptor contributes significantly to the clearance of LDL from plasma but plays a lesser role in the clearance of larger apoB-containing lipoproteins. Furthermore, these data also indicate that absence of a LDL receptor in humans substantially influences the apoB PR in vivo.
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Affiliation(s)
- John S Millar
- Department of Medicine, University of Pennsylvania, 644 BRB II/III, 421 Curie Blvd, Philadelphia, PA 19104, USA.
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Bailhache E, Briand F, Nguyen P, Krempf M, Magot T, Ouguerram K. Metabolism of cholesterol ester of apolipoprotein B100-containing lipoproteins in dogs: evidence for disregarding cholesterol ester transfer. Eur J Clin Invest 2004; 34:527-34. [PMID: 15305886 DOI: 10.1111/j.1365-2362.2004.01387.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND It has been shown that dogs exhibit no cholesterol ester transfer protein (CETP) activity in vitro, in contrast to humans. The aim of our study was to determine modalities of in vivo plasma cholesterol ester turnover in this species, using a kinetic approach with stable isotopes. MATERIALS AND METHODS Kinetics of very low-density lipoprotein (VLDL) and low-density lipoprotein (LDL) were studied in seven adult male Beagle dogs using a dual isotope approach through endogenous labelling of both their cholesterol moiety and their protein moiety. A primed constant infusion of both [1,2(13)C]acetate and [5,5,5-2H3]leucine enabled us to obtain measurable deuterium enrichments by gas chromatography-mass spectrometry for plasma leucine and apoB100, as well as measurable 13C enrichment by gas chromatography-combustion-isotopic ratio mass spectrometry for unesterified cholesterol and cholesterol ester in the VLDL and LDL. Two identical multicompartmental models (SAAM II) were used together for the analysis of tracer kinetics' data of proteins and cholesterol. RESULTS Characterization of the apoB100-containing lipoprotein cholesterol ester model allowed determination of kinetic parameters of VLDL and LDL cholesterol ester metabolism. We succeeded in modelling VLDL and LDL cholesterol ester metabolism and apoB100 metabolism simultaneously. Fractional catabolic rate (FCR) of apoB100 and CE had the same values. Introducing cholesterol ester transfer between lipoproteins in the model did not significantly improve the fit. Total VLDL FCR was 2.97 +/- 01.47 h(-1). Approximately one-quarter corresponded to the direct removal of VLDL (0.81 +/- 00.34 h(-1)) and the remaining three-quarters corresponded to the fraction of VLDL converted to LDL, which represented a conversion of VLDL into LDL of 2.16 +/- 01.16 h(-1). Low-density lipoproteins were produced exclusively from VLDL conversion and were then removed (0.031 +/- 0.004 h(-1)) from plasma. CONCLUSION These kinetic data showed that VLDL cholesterol ester and LDL cholesterol ester metabolism followed VLDL and LDL apoB100 metabolism, and that consequently there is no in vivo transfer of cholesterol ester in dogs.
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Affiliation(s)
- E Bailhache
- Centre de Recherche en Nutrition Humaine, INSERM U539, CHU Nantes, France
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Ouguerram K, Chetiveaux M, Zair Y, Costet P, Abifadel M, Varret M, Boileau C, Magot T, Krempf M. Apolipoprotein B100 metabolism in autosomal-dominant hypercholesterolemia related to mutations in PCSK9. Arterioscler Thromb Vasc Biol 2004; 24:1448-53. [PMID: 15166014 DOI: 10.1161/01.atv.0000133684.77013.88] [Citation(s) in RCA: 155] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE We have reported further heterogeneity in familial autosomal-dominant hypercholesterolemia (FH) related to mutation in proprotein convertase subtilisin/kexin type 9 (PCSK9) gene previously named neural apoptosis regulated convertase 1 (Narc-1). Our aim was to define the metabolic bases of this new form of hypercholesterolemia. METHODS AND RESULTS In vivo kinetics of apolipoprotein B100-containing lipoproteins using a 14-hour primed constant infusion of [2H3] leucine was conducted in 2 subjects carrying the mutation S127R in PCSK9, controls subjects, and FH subjects with known mutations on the low-density lipoprotein (LDL) receptor gene (LDL-R). Apo B100 production, catabolism, and transfer rates were estimated from very LDL (VLDL), intermediate-density lipoprotein (IDL), and LDL tracer enrichments by compartmental analysis. PCSK9 mutation dramatically increased the production rate of apolipoprotein B100 (3-fold) compared with controls or LDL-R mutated subjects, related to direct overproduction of VLDL (3-fold), IDL (3-fold), and LDL (5-fold). The 2 subjects also showed a decrease in VLDL and IDL conversion (10% to 30% of the controls). LDL fractional catabolic rate was slightly decreased (by 30%) compared with controls but still higher than LDL-R-mutated subjects. CONCLUSIONS These results showed that the effect of the S127R mutation of PCSK9 on plasma cholesterol homeostasis is mainly related to an overproduction of apolipoprotein B100.
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Affiliation(s)
- Khadija Ouguerram
- INSERM U 539, Centre de Recherche en Nutrition Humaine de Nantes, France
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Ouguerram K, Magot T, Zaïr Y, Marchini JS, Charbonnel B, Laouenan H, Krempf M. Effect of atorvastatin on apolipoprotein B100 containing lipoprotein metabolism in type-2 diabetes. J Pharmacol Exp Ther 2003; 306:332-7. [PMID: 12684543 DOI: 10.1124/jpet.103.048991] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Seven hypertriglyceridemic patients with type-2 diabetes were treated with atorvastatin (40 mg/day) for 2 months. Kinetics of apolipoprotein B100 (apoB100)-containing lipoproteins were determined before and after atorvastatin treatment and compared with data obtained in five normolipidemic volunteers. ApoB100 metabolism was studied using stable isotopes and multicompartmental modeling. Compared with normolipidemic obese subjects, type-2 diabetic patients had a higher apoB100 concentration in very low-density lipoproteins (VLDL), intermediate-density lipoproteins (IDL), and low-density lipoproteins (LDL) (P < 0.005). Kinetic analysis showed an increase in the total apoB100 production rate (P < 0.005) related to VLDL apoB100 overproduction (P < 0.005). Patients were also characterized by a lower fractional catabolic rate (FCR) in VLDL (not significant) or IDL (P < 0.005) mainly related to a decrease in VLDL and IDL delipidation rate (P < 0.005). Catabolism of LDL was also lower in diabetic patients (P < 0.05). Atorvastatin treatment significantly decreased plasma triglycerides (P < 0.05), total and LDL cholesterol (P < 0.05), apoB100 in LDL, IDL, and VLDL (P < 0.05). Treatment significantly decreased total apoB100 production rate (P < 0.05), but only for VLDL (P < 0.05). Treatment normalized FCR in IDL and LDL (P < 0.05). We concluded that atorvastatin improved lipid abnormalities in type-2 diabetic patients not only by increasing the clearance of apoB100-containing lipoproteins but also by decreasing VLDL production.
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Affiliation(s)
- Khadija Ouguerram
- Centre de Recherche en Nutrition Humaine, INSERM U539-Hôtel Dieu, France.
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Chanson NF, Lontie JF, Gulik A, Férézou J, Carpentier YA. LDL binding to lipid emulsion particles: effects of incubation duration, temperature, and addition of plasma subfractions. Lipids 2002; 37:573-80. [PMID: 12120956 DOI: 10.1007/s11745-002-0935-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Lipid emulsions used in parenteral nutrition interact with lipoproteins leading to exchanges of lipids and acquisition of several apolipoproteins (apo). It has been previously observed that, during in vitro incubation of emulsions with purified LDL, a variable fraction of LDL binds to TG-rich emulsion particles. The purpose of this study was to better characterize such an interaction. Two emulsions containing 20% soybean oil (Endolipid, B. Braun AG, Melsungen, Germany) or fish oil were incubated with LDL, either alone or in the presence of various plasma subfractions, for different durations and at different temperatures. The fraction named M-LE (containing TG-rich particles modified after incubation) was separated by ultracentrifugation or gel filtration chromatography, and the apoB content was measured as an index of LDL binding to TG-rich emulsion particles. The formation of such complexes was visualized by freeze-fracture electron microscopy. LDL binding was not influenced by the method used for M-LE isolation. Binding occurred quickly, did not increase with prolonged incubation, was inversely related to increasing incubation or ultracentrifugation temperature, and withstood 40 h of ultracentrifugation at 163,000 x g. The presence of glycerol or excess phospholipids in the emulsion did not markedly affect the formation of the complexes. In contrast, adding very small amounts of lipoprotein-poor plasma (d > 1.210 g/mL) or HDL markedly reduced the process, and albumin had no effect. The TG composition of the emulsion influenced the binding of LDL to TG-rich particles, since more apoB was found in M-LE from fish oil than from soybean oil emulsion.
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Affiliation(s)
- Nathalie F Chanson
- L. Deloyers Laboratory for Experimental Surgery, Université Libre de Bruxelles, Brussels, Belgium
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Young IS, Nicholls DP. Lipid metabolism. Curr Opin Lipidol 2001; 12:227-9. [PMID: 11264993 DOI: 10.1097/00041433-200104000-00016] [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] [Indexed: 11/25/2022]
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Tomkin GH, Owens D. Abnormalities in apo B-containing lipoproteins in diabetes and atherosclerosis. Diabetes Metab Res Rev 2001; 17:27-43. [PMID: 11241889 DOI: 10.1002/dmrr.179] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Atherosclerosis is the major cause of death in patients with diabetes. Low-density lipoprotein (LDL) being the most important cholesterol-carrying lipoprotein has been studied extensively in both diabetes and non-diabetes. This paper reviews the literature but also focuses on the precursors of LDL and in particular the postprandial apo B-containing lipoproteins. Abnormalities in the postprandial lipoproteins and alteration in chylomicron assembly and clearance are discussed and the evidence presented suggesting the importance of dysregulation of these lipoproteins in atherosclerotic progression. The relationship between chylomicron production in the intestine and hepatic release of very low-density lipoproteins (VLDL) is explored, as is the interrelationship between clearance rates of these lipoproteins. The size of LDL influences its atherogenicity. VLDL composition and size in relation to its influence on LDL is discussed. The effect of diet on the composition of lipoproteins and the relationship between fatty acid composition and clearance is reviewed. Evidence that diabetic control beneficially alters lipoprotein composition is presented suggesting how improved diabetic control may reduce atherosclerosis. The review concludes with a discussion on the effect of the apo B-containing lipoproteins and their modification through glycation and oxidation on macrophage and endothelial function.
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Affiliation(s)
- G H Tomkin
- Department of Diabetes and Endocrinology, Trinity College Dublin and Adelaide and Meath Hospital, Dublin, Ireland
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Current awareness. JOURNAL OF MASS SPECTROMETRY : JMS 2000; 35:1363-1374. [PMID: 11114097 DOI: 10.1002/1096-9888(200011)35:11<1363::aid-jms984>3.0.co;2-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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