OXIDIZED LDL (OXLDL) INDUCES PRODUCTION OF PLATELET-DERIVED GROWTH-FACTOR AA (PDGF AA) FROM AORTIC SMOOTH-MUSCLE CELLS

Objectives: Elevated concentrations of oxidised low density lipoprotei ns (OxLDL) are associated with accelerated atherogenesis. The aim of o ur study was to determine the effect of OxLDL on the proliferation rat e and platelet derived growth factor (PDGF) AA production on aortic sm ooth muscle cells. High density lipoproteins (HDL), which are known to have a protective effect against atherosclerosis, were used as contro l. Materials and methods: Bovine aortic smooth muscle cells were grown in presence of increased concentrations of OxLDL and HDL and in prese nce of control medium culture (DMEM). Proliferation rate was assessed by H-3-thymidine uptake. PDGF AA production was determined by ELISA an d Western Blot Analysis. Results: OxLDL increased the proliferation ra te of aortic smooth muscle cells as compared to DMEM and HDL (p<0.001) . The mitogenic activity of OxLDL on smooth muscle cells was reduced a dding anti-PDGF AA antibodies (p<0.001). PDGF AA production by aortic smooth muscle cells was increased after exposure to OxLDL as compared to DMEM (p<0.001). HDL significantly reduced the production of PDGF AA by aortic smooth muscle cells (p<0.001). Conclusions: Part of the ath erogenic effect of OxLDL is mediated through the autocrine production of PDGF AA from aortic smooth muscle cells.