In vitro and in vivo angiogenic activity of osteoarthritic and osteoporotic osteoblasts is modulated by VEGF and vitamin D3 treatment

Vascular Endothelial Growth Factor (VEGF) is a potent angiogenic factor, which also regulates bone remodeling. Osteoblasts not only respond to VEGF stimulation, but also express and synthesize this factor. The present study was aimed to evaluate in vitro differences in VEGF production and expression of cultured human osteoblastic cells derived from healthy donors and from subjects affected by osteoarthritis and osteoporosis, under basal conditions than after vitamin D3, and to investigate the angiogenic activity of culture media obtained by these cells in chick embryo chorioallantoic membrane (CAM) assay. The results showed that normal and pathological osteoblasts produce and express VEGF and 1,25 dihydroxy-vitamin D3 treatment increases protein and m-RNA VEGF levels. In addition culture media of pathological osteoblasts induce a strong angiogenic response, greater than observed with culture medium of normal cells, suggesting the involvement of osteoblast-derived VEGF in the pathogenesis of bone diseases.