Plasma apolipoprotein(b) to LDL cholesterol ratio as a marker of small, dense LDL

Abstract

A predominance of small, dense LDL in plasma is predictive of coronary risk' and a hallmark feature of an atherogenic lipoprotein phenotype (ALP).2 The measurement of small, dense LDL (LDL pattern 'B') has traditionally been based on the separation of LDL subclasses by density gradient ultra-centrifugation and gradient gel electrophoresis. However, these techniques are expensive, time consuming and unsuitable for routine applications and the screening of large cohorts. While more rapid procedures are currently under development, it is possible to gain information on the nature of LDL subclasses by measuring the ratio of plasma apolipoprotein(b) [apo(b)] to LDL cholesterol (LDL-C),3 since this will increase as LDL particles become small and dense.The aim of this study was to examine the strength of the relationship between the concentration of small, dense LDL as measured by density gradient centrifugation and the ratio of plasma apo(b) to LDL-C, with a view to this ratio acting as a surrogate marker for small, dense LDL. MATERIALS AND METHODSBlood samples were collected from normal, healthy subjects (n = 58) who were being screened routinely for plasma LDL subclasses. The subjects (56 men, 2 women, aged 20-60 years) were pre-selected for the presence of moderately raised plasma triglyceride (TO), with or without moderately raised plasma cholesterol, for participation in dietary intervention studies. All subjects were free-living, non-smoking, nonobese and free of medication known to affect lipid metabolism. LDL subclasses were determined at the University of Surrey by density gradient centrifugation" and the LDL subclass

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“…The LDL cholesterol/Apo B ratio is a well-accepted surrogate of LDL particle size, with large ratios being associated with large, less atherogenic LDL particles. 22,23 Wakatsuki et al 24 demonstrated that transdermal estrogen administration de- …”

What is the best predictor of the atherogenic LDL subclass phenotype ‘pattern B’ in patients with type 2 diabetes mellitus?

“…An extension of this approach is the LDL-C:Apo-B ratio, considered a surrogate for LDL particle density and a low value indicating the presence of sdLDL. 12 More recently, a direct automated assay for sdLDL has become available; this is based on well-characterized detergents and enzymes that selectively react with the different lipid fractions. Both the LDL-C:Apo-B ratio and the direct sdLDL assay have the potential to simplify analysis of LDL subfractions, and thus refine cardiovascular risk assessment.…”