This Article Full Text Full Text (PDF) Submit a related Letter to the Editor Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Copyright Permission Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Pruneta, V. Articles by Moulin, P. Search for Related Content PubMed PubMed Citation Articles by Pruneta, V. Articles by Moulin, P.

Ex Vivo Measurement of Lipoprotein Lipase-Dependent Very Low Density Lipoprotein (VLDL)-Triglyceride Hydrolysis in Human VLDL: An Alternative to the Postheparin Assay of Lipoprotein Lipase Activity?¹

Laboratoire de Métabolisme des Lipides (V.P., D.A., G.P., P.M.) CNRS ESA 5014 and Service d’Endocrinologie et des Maladies de la Nutrition (P.M., F.B.), Hôpital de l’Antiquaille, Lyon; Laboratoire de Biochimie (C.M.), Centre Hospitalier Lyon-Sud, Lyon; Service d’Endocrinologie-Diabétologie-Maladies Métaboliques, INSERM U498 (L.D., B.V.), Centre Hospitalier Universitaire Dijon, Dijon, France

Address correspondence and requests for reprints to: Valérie Pruneta, Laboratoire de Métabolisme des Lipides, CNRS ESA 5014, Hôpital de l’Antiquaille, 1 rue de l’Antiquaille, 69005 Lyon, France.

The plasma lipolysis of triglyceride (TG)-rich lipoproteins is mainly due to the activity of lipoprotein lipase (LPL). Albeit important for our analysis of certain physiopathological situations, the determination of the magnitude of LPL-dependent lipolysis is not easy to perform. This essentially results from the binding of LPL to the luminal surface of vascular endothelium. The measurements of the whole putative LPL activity have been achieved after injection of heparin, a procedure that releases LPL from endothelium. However, the physiopathological relevance of this postheparin lipolysis assay (PHLA) remains questionable because it has never been demonstrated that the bulk of endothelium-bound LPL was active.

It has been recently shown that a small part of LPL is associated to circulating lipoproteins in nonheparinized plasma, raising the possibility that the lipolysis mediated by this circulating LPL might reflect the overall LPL-dependent TG hydrolysis in plasma. To address this question, we developed a new lipolysis assay in which the very low density lipoprotein (VLDL)-bound LPL-dependent VLDL-TG hydrolysis (LVTH) was directly determined through the measurement of nonesterified fatty acid (NEFA) release during in vitro incubations. LVTH measurements were performed in control subjects, in type 2 diabetics, and in either heterozygous or homozygous LPL-deficient patients. In the latter group, LVTH values were extremely low. Those of heterozygous patients and of diabetics were similarly decreased by about 40% with respect to control group. Plasma TG concentrations exhibited an inverse relationship with LVTH level. In a subgroup of subjects, LVTH and PHLA were positively correlated and the inverse correlation of LVTH with plasma or VLDL-TG concentration was stronger than that obtained with PHLA. To further study the validity of this new assay, we measured LVTH in nine subjects who were studied for their catabolism of VLDL labeled with stable isotope. No relation was observed between the direct hepatic removal of VLDL and LVTH, whereas the latter was strikingly correlated with the rate of conversion of VLDL to intermediary density lipoprotein.

Collective consideration of these findings strongly suggests that LVTH is a physiologically relevant index which could advantageously replace the measurements of PHLA in numerous physiopathological situations.

This article has been cited by other articles:

				S. J. Hernandez Vallejo, M. Alqub, S. Luquet, C. Cruciani-Guglielmacci, P. Delerive, J.-M. Lobaccaro, A.-D. Kalopissis, J. Chambaz, M. Rousset, and J.-M. Lacorte Short-term adaptation of postprandial lipoprotein secretion and intestinal gene expression to a high-fat diet Am J Physiol Gastrointest Liver Physiol, April 1, 2009; 296(4): G782 - G792. [Abstract] [Full Text] [PDF]

				J. Rip, M. C. Nierman, C. J. Ross, J. W. Jukema, M. R. Hayden, J. J.P. Kastelein, E. S.G. Stroes, and J. A. Kuivenhoven Lipoprotein Lipase S447X: A Naturally Occurring Gain-of-Function Mutation Arterioscler Thromb Vasc Biol, June 1, 2006; 26(6): 1236 - 1245. [Abstract] [Full Text] [PDF]

				S. Ibrahim, A. Djimet-Baboun, V. Pruneta-Deloche, C. Calzada, M. Lagarde, and G. Ponsin Transfer of very low density lipoprotein-associated phospholipids to activated human platelets J. Lipid Res., February 1, 2006; 47(2): 341 - 348. [Abstract] [Full Text] [PDF]

				M. C. Nierman, B. H.C.M.T. Prinsen, J. Rip, R. J. Veldman, J. A. Kuivenhoven, J. J.P. Kastelein, M. G.M. de Sain-van der Velden, and E. S.G. Stroes Enhanced Conversion of Triglyceride-Rich Lipoproteins and Increased Low-Density Lipoprotein Removal in LPLS447X Carriers Arterioscler Thromb Vasc Biol, November 1, 2005; 25(11): 2410 - 2415. [Abstract] [Full Text] [PDF]

				V. Pruneta-Deloche, A. Sassolas, G. M. Dallinga-Thie, F. Berthezene, G. Ponsin, and P. Moulin Alteration in lipoprotein lipase activity bound to triglyceride-rich lipoproteins in the postprandial state in type 2 diabetes J. Lipid Res., May 1, 2004; 45(5): 859 - 865. [Abstract] [Full Text] [PDF]