Study of agreement between LDL size as measured by nuclear magnetic resonance and gradient gel electrophoresis

D.R Witte,M.R Taskinen,H Perttunen-Nio,A Van Tol,S Livingstone,H.M Colhoun

doi:10.1194/jlr.m300395-jlr200

D.R Witte, M.R Taskinen + Show 4 more

Open Access

https://doi.org/10.1194/jlr.m300395-jlr200

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Abstract

LDL particle size can be measured by gradient gel electrophoresis (GGE) and NMR. The agreement between the two methods has not been extensively evaluated. Therefore, we measured LDL size by NMR and GGE in 324 individuals (152 with type 1 diabetes and 172 controls). The Spearman correlation between both methods was 0.39 [95% confidence interval (CI) = 0.29, 0.48]. The average difference was 5.38 nm (NMR being smaller), but it increased with increasing LDL size. Less than 50% of people classified as pattern B on GGE were classified as pattern B on NMR (kappa = 0.31; 95% CI = 0.17, 0.45). Agreement was lower for diabetic subjects compared with controls, for women compared with men, and for subjects with triglycerides less than 1.30 mmol/l compared with subjects with triglycerides greater than 1.30 mmol/l. External validation showed that cholesteryl ester transfer rate was related to LDL size on GGE in all subgroups and to LDL size on NMR only in men and nondiabetic subjects. Our findings show that agreement between NMR- and GGE-based LDL size is far from perfect and is not consistent across subgroups of patients. In particular, the two methods should not be assumed to be interchangeable in women and diabetic subjects. Whether NMR or GGE predicts cardiovascular disease risk better has not yet been evaluated.

Highlights

LDL particle size can be measured by gradient gel electrophoresis (GGE) and NMR
The corporate documentation provided by LipoScience [14] states that LDL subclass diameters are uniformly ‫ف‬5 nm smaller than those estimated by GGE and that an average LDL particle size of р20.5 nm on NMR is equivalent to pattern B on GGE
We examined the relation between the average LDL size measurement on NMR and the peak LDL size on GGE, calculating Spearman’s rho for the group as a whole and for subgroups according to gender, the presence of diabetes mellitus, and tertiles of triglycerides

Summary

Introduction

LDL particle size can be measured by gradient gel electrophoresis (GGE) and NMR. We measured LDL size by NMR and GGE in 324 individuals (152 with type 1 diabetes and 172 controls). Study of agreement between LDL size as measured by nuclear magnetic resonance and gradient gel electrophoresis. A number of methods for the assessment of lipoprotein size exist, the most widely used being gradient gel electrophoresis (GGE) [15] and proton NMR spectroscopy [16, 17]. Based on empirically measured signal amplitudes of purified VLDL, LDL, and HDL subclasses, this method distin-. Journal of Lipid Research Volume 45, 2004 1069 guishes the component peaks associated with lipoprotein subclasses These subclass signal amplitudes are regarded as a direct measure of the levels of subclass particles [17]

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