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Di Filippo M, Marçais C, Charrière S, Marmontel O, Broyer M, Delay M, Merlin M, Nollace A, Valéro R, Lagarde M, Pruneta-Deloche V, Moulin P, Sassolas A. Post-heparin LPL activity measurement using VLDL as a substrate: a new robust method for routine assessment of plasma triglyceride lipolysis defects. PLoS One 2014; 9:e96482. [PMID: 24788417 PMCID: PMC4008628 DOI: 10.1371/journal.pone.0096482] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2013] [Accepted: 04/07/2014] [Indexed: 01/27/2023] Open
Abstract
Background Determination of lipoprotein lipase (LPL) activity is important for hyperchylomicronemia diagnosis, but remains both unreliable and cumbersome with current methods. Consequently by using human VLDL as substrate we developed a new LPL assay which does not require sonication, radioactive or fluorescent particles. Methods Post-heparin plasma was added to the VLDL substrate prepared by ultracentrifugation of heat inactivated normolipidemic human serums, diluted in buffer, pH 8.15. Following incubation at 37°c, the NEFA (non esterified fatty acids) produced were assayed hourly for 4 hours. LPL activity was expressed as µmol/l/min after subtraction of hepatic lipase (HL) activity, obtained following LPL inhibition with NaCl 1.5 mmol/l. Molecular analysis of LPL, GPIHBP1, APOA5, APOC2, APOE genes was available for 62 patients. Results Our method was reproducible (coefficient of variation (CV): intra-assay 5.6%, inter-assay 7.1%), and tightly correlated with the conventional radiolabelled triolein emulsion method (n = 26, r = 0.88). Normal values were established at 34.8±12.8 µmol/l/min (mean±SD) from 20 control subjects. LPL activities obtained from 71 patients with documented history of major hypertriglyceridemia showed a trimodal distribution. Among the 11 patients with a very low LPL activity (<10 µmol/l/min), 5 were homozygous or compound heterozygous for LPL or GPIHBP1 deleterious mutations, 3 were compound heterozygous for APOA5 deleterious mutations and the p.S19W APOA5 susceptibility variant, and 2 were free of any mutations in the usual candidate genes. No homozygous gene alteration in LPL, GPIHBP1 and APOC2 genes was found in any of the patients with LPL activity >10 µmol/l/min. Conclusion This new reproducible method is a valuable tool for routine diagnosis and reliably identifies LPL activity defects.
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Affiliation(s)
- Mathilde Di Filippo
- UF Dyslipidémies Cardiobiologie, Département de Biochimie et Biologie Moléculaire, Centre de Biologie et de Pathologie Est, Laboratoire de Biologie Médicale Multi Sites, Hospices Civils de Lyon, Bron, France
- INSERM U1060, INSA de Lyon, INRA U1235, Univ Lyon-1, Université de Lyon, Villeurbanne, Oullins, France
- * E-mail:
| | - Christophe Marçais
- INSERM U1060, INSA de Lyon, INRA U1235, Univ Lyon-1, Université de Lyon, Villeurbanne, Oullins, France
- Laboratoire de Biochimie spécialisée, Centre de Biologie Sud, Centre Hospitalier Lyon-Sud, Laboratoire de Biologie Médicale Multi Sites, Hospices Civils de Lyon, Pierre-Bénite, France
| | - Sybil Charrière
- INSERM U1060, INSA de Lyon, INRA U1235, Univ Lyon-1, Université de Lyon, Villeurbanne, Oullins, France
- Fédération d′endocrinologie, maladies métaboliques, diabète et nutrition, Hôpital Louis Pradel, Hospices Civils de Lyon, Bron, France
| | - Oriane Marmontel
- UF Dyslipidémies Cardiobiologie, Département de Biochimie et Biologie Moléculaire, Centre de Biologie et de Pathologie Est, Laboratoire de Biologie Médicale Multi Sites, Hospices Civils de Lyon, Bron, France
| | - Martine Broyer
- UF Dyslipidémies Cardiobiologie, Département de Biochimie et Biologie Moléculaire, Centre de Biologie et de Pathologie Est, Laboratoire de Biologie Médicale Multi Sites, Hospices Civils de Lyon, Bron, France
| | - Mireille Delay
- Laboratoire de Biochimie spécialisée, Centre de Biologie Sud, Centre Hospitalier Lyon-Sud, Laboratoire de Biologie Médicale Multi Sites, Hospices Civils de Lyon, Pierre-Bénite, France
| | - Micheline Merlin
- Laboratoire de Biochimie spécialisée, Centre de Biologie Sud, Centre Hospitalier Lyon-Sud, Laboratoire de Biologie Médicale Multi Sites, Hospices Civils de Lyon, Pierre-Bénite, France
| | - Axel Nollace
- UF Dyslipidémies Cardiobiologie, Département de Biochimie et Biologie Moléculaire, Centre de Biologie et de Pathologie Est, Laboratoire de Biologie Médicale Multi Sites, Hospices Civils de Lyon, Bron, France
| | - René Valéro
- Département de Nutrition, Maladies Métaboliques, Endocrinologie, APHM, Hôpital de la Timone, Aix-Marseille Université, UMR_S 1062, UMR_A1260, Marseille, France
| | - Michel Lagarde
- INSERM U1060, INSA de Lyon, INRA U1235, Univ Lyon-1, Université de Lyon, Villeurbanne, Oullins, France
| | - Valérie Pruneta-Deloche
- INSERM U1060, INSA de Lyon, INRA U1235, Univ Lyon-1, Université de Lyon, Villeurbanne, Oullins, France
| | - Philippe Moulin
- INSERM U1060, INSA de Lyon, INRA U1235, Univ Lyon-1, Université de Lyon, Villeurbanne, Oullins, France
- Fédération d′endocrinologie, maladies métaboliques, diabète et nutrition, Hôpital Louis Pradel, Hospices Civils de Lyon, Bron, France
| | - Agnès Sassolas
- UF Dyslipidémies Cardiobiologie, Département de Biochimie et Biologie Moléculaire, Centre de Biologie et de Pathologie Est, Laboratoire de Biologie Médicale Multi Sites, Hospices Civils de Lyon, Bron, France
- INSERM U1060, INSA de Lyon, INRA U1235, Univ Lyon-1, Université de Lyon, Villeurbanne, Oullins, France
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