Measurement of low-density lipoprotein particle size by high-performance gel-filtration chromatography

We describe a new technique for measuring LDL size by high-performance gel-filtration chromatography (HPGC). LDL was subjected to chromatography, and the column effluent was monitored at 280 nm. The retention time of the LDL peak was used to calculate the LDL diameter. We compared the HPGC method with gradient gel electrophoresis (GGE) on 2-10% nondenaturing polyacrylamide gels. In a group of 60 non-insulin-dependent diabetes mellitus patients, LDL size as measured by HPGC and GGE was highly correlated (r = 0.88, P <0.001). Good reproducibility, high precision, and the possibility of analyzing large series of samples are the main advantages of the automated HPGC method. Within-run and between-run CV for LDL size measured by HPGC were <0.1% and 0.2%, respectively. There was a significant inverse association between LDL size measured by HPGC and the logarithm of plasma triglycerides (r = -0.84, P <0.001), and a significant positive association with the LDL free cholesterol/protein ratio (r = 0.89, P <0.001).