Effect of glycated low density lipoprotein on smooth muscle cell proliferation

Background. We investigated the effect of glycated low density lipoprotein (LDL) on smooth muscle cell proliferation. Methods. Blood was drawn from 6 healthy subjects after overnight fasting. N ative LDL was obtained by separating LDL from the samples with sequential u ltracentrifugation. Glycated LDL was prepared by glycating the native LDL i n vitro. Native and glycated LDL were added to a medium containing cultured porcine coronary artery smooth muscle cells, and the change in cell prolif eration was examined after 24, 48, 72, and 96 hs. The cells were counted us ing a cell counting kit (Dojin Chemical Co., Ltd.). Results. There was no significant difference in the cell count between the control group, in which only PBS was added, and the native LDL group. Howev er, cell proliferation was appreciably higher in the glycated LDL group tha n in the native LDL group. The mean total cell count at 24, 48, 72 and 96 h s was significantly higher (p<0.01) in the glycated LDL group (median: 0.84 3; range: 0.576-1.060) than in the native LDL group (median: 0.541; range: 0.282-0.683). Conclusions. These findings suggest that glycated LDL induces significantly greater acceleration of smooth muscle cell proliferation than does native LDL. Therefore, the acceleration of smooth muscle cell proliferation requir es modification of LDL.