Introduction: According to recent researches, changes in the composition of LDL particles affect their surface charge and structural features (their diameters, for example), modifying their morphology and metabolism in the plasma. In the present study, the relationship of LDL particles size with their zeta potential were assessed in patients with coronary artery disease in comparison with control subjects.

Materials & methods:  In the case and control study, 30 patients with coronary artery disease and 30 control subjects were selected based on the clinical and angiographic parameters. The size and zeta potential of LDL particles were measured using zeta sizer instrument.

Findings: Results of this study showed that, LDL mean particle size in patients (24.18 ± 1.6 nm) was significantly higher than that of control subjects (25.26 ± 0.63 nm)( P=./0001). Furthermore, the zeta potential level in patients (-25.08 ± 0.77 mV) was significantly lower than that of control subjects (-23.65 ± 1.56 mV) (P=./0001). This means that the negative charge of LDL particles was further in patients than in control subjects. On the other hand, there was a significant correlation between LDL mean particle size and zeta potential of the particles in patients. However, the correlation was not significant in control subjects.

Discussion & conclusions: Low density lipoprotein (LDL) particles are heterogeneous entities based on their size, density and composition. It is conceived that among the particles the smaller and denser ones would be more atherogenic. The present study demonstrated that LDL particles with smaller size and more negative charges are associated with increased risk of cardiovascular disease. Also, changes in the diameter of LDL particles are associated with the changes in the zeta potentials of the particles.