Effects of vascular endothelial growth factor (VEGF) on cultured rat sinusoidal endothelial cells

VEGF is an endothelial cell-specific mitogen and angiogenic inducer released by a variety of tumor cells. Messenger-RNA of VEGF was demonstrated in hepatocytes, but not in nonparenchymal cells. In liver regeneration, VEGF from hepatocytes may be proliferative stimuli for sinusoidal endothelial cells. In the present study, effects of VEGF in tube-like structure formation and proliferation of cultured rat sinusoidal endothelial cells were studied and compared with those of other growth factors. Isolated sinusoidal endothelial cells were plated on culture dishes coated with type-1 collagen or Matrigel. Cultured sinusoidal endothelial cells were incubated in the medium containing various growth factors (EGF, a-FGF, b-FGF, HGF and VEGF). Sinusoidal endothelial cells cultured on type-1 collagen-coated dishes were hardly maintained more than 5 days after seeding. Sinusoidal endothelial cells in the medium containing VEGF (20ng/ml) on type-1 collagen-coated dishes formed a cobblestone appearance, and cells were well maintained for 2 weeks in culture. However, other growth factors (EGF, a-FGF, b-FGF, HGF) were not demonstrated to accelerate the cell growth and to maintain the cells in culture. Sinusoidal endothelial cells cultured in the medium containing VEGF showed surprising cell proliferation and retained characteristic endothelial pores and uptake of acetylated LDL, but not FactorVIII-related antigen, even after 2 weeks in culture. Tube-like structure formation in cultured sinusoidal endothelial cells was accelerated by a-FGF, b-FGF and markedly by HGF, but not by EGF nor VEGF. In the present study, VEGF demonstrated potent effects in cell proliferation and cell maintenance of cultured rat sinusoidal endothelial cells. Since HGF, a-FGF, and b-FGF showed stimulatory activity of tube-like structure in cultured sinusoidal endothelial cells, VEGF may be involved in the reconstruction of the sinusoid in liver regeneration, cooperating with other growth factors.