Oxidized lipoprotein(a) increases the expression of platelet-derived growth factor-B in human umbilical vein...

Lipoprotein(a) ¿Lp(a) has been demonstrated to be an independent risk factor for atherosclerosis and restenosis after angioplasty. However, the precise mechanism by which it contributes to the development of both remains unclear. Platelet-derived growth factor (PDGF) is one of the key factors that induce the proliferation and migration of vascular smooth muscle cells. The present study investigated the effects of native and oxidized LDL ¿n-LDL and ox-LDL and Lp(a) ¿n-Lp(a) and ox-Lp(a) on the expression of PDGF-B in cultured human umbilical vein endothelial cells (HUVECs). Results showed that PDGF-B expression was not influenced by n-LDL, but was moderately increased by ox-LDL and n-Lp(a). Ox-Lp(a) was the most potent stimulus for PDGF-B expression, increasing it in HUVECs by 156%+/-18% at 5 nmol/l and 219%+/-42% at 20 nmol/l. Northern Blot analysis demonstrated that the amount of PDGF-B mRNA was markedly increased after treatment with ox-Lp(a) but not n-LDL, ox-LDL and n-Lp(a). These results demonstrate that ox-Lp(a) can elicit PDGF-B expression in HUVECs, which may thereby influence the pathogenesis of atherosclerosis and restenosis after angioplasty.