Preparation of degreased very low density lipoprotein and its impact on vascular endothelial cell function

  Background  As a major risk factor for atherogenesis, very low-density lipoprotein (VLDL) is composed of triglyceride, cholesterol and multiple apolipoproteins. Due to the difficulty of apolipoprotein isolation, few studies have focused on the effect of multiple apolipoproteins contained in VLDL on atherosclerosis.

  Objective  To purify apolipoprotein very low-density lipoprotein (ApoVLDL) by modified precipitation-concentration method and assess the effect of ApoVLDL on the damage and adhesion function of EA.hy926 endothelial cells.

  Methods  The low density lipoprotein in serum was removed by precipitation method, and then concentrated by ultrafiltration centrifuge tube and separated by density gradient centrifugation to obtain VLDL. ApoVLDL was obtained by VLDL defatting. Different concentrations (blank control group, 50 μ g/mL, 100 μ g/mL, 200 μ G/mL) of ApoVLDL was incubated with EA.hy926 endothelial cells to evaluate the effect of ApoVLDL on the viability and adhesion function of EA.hy926 endothelial cells.

  Results  ApoVLDL could be obtained by improved precipitation concentration method. The particle size of ApoVLDL was (141.3 ± 0.64) nm, the polydispersity index (PDI) was (0.27 ± 0.0076), the Zeta potential was (-18.73 ± 0.58) mV, with uniform size and relatively stable dispersion system. After incubation of EA.hy926 endothelial cells with ApoVLDL for 24 h, the cell viability decreased significantly in a dose-dependent manner (P<0.0001). Cell migration of EA.hy926 endothelial cells was significantly inhibited after treatment with 100 μg/mL of ApoVLDL in the scratch motility assay (11.10% ± 0.693% vs 50.57% ± 2.66% in the blank control group, P<0.001). At the same time, the number of leukocytes adhered to EA.hy926 endothelial cells increased significantly (22.13 ± 1.04 vs 7.25 ± 1.58 in the blank control group, P<0.01), and the expression of VCAM-1 mRNA in EA.hy926 endothelial cells also increased significantly (P<0.01).

  Conclusion  ApoVLDL can be effectively prepared by improved precipitation concentration method. EA.hy926 endothelial cell dysfunction induced by ApoVLDL can provide a specific cell injury model in vitro for the study of endothelial dysfunction induced by Apolipoprotein C - Ⅲ (Apo C - Ⅲ).