Vascular endothelial growth factor is expressed in human fetal growth cartilage

Angiogenesis is a crucial event in endochondral ossification, Chemoattracta nts and mitogens for endothelial cells (such as basic fibroblast growth fac tor [bFGF] and transforming growth factor beta [TGF-beta]), which act as lo cal regulators of the process, are synthesized by chondrocytes under severa l stimuli and in relation to the differentiation stage of the cartilage. Va scular endothelial growth factor (VEGF) is a 44-kDa protein well known as a potent angiogenic molecule owing to its mitogenic and permeability-causing properties. In this work, VEGF was located by immunohistochemistry in grow th plate cartilage of human fetuses (20-22 weeks old) and its expression wa s demonstrated by reverse-transcription polymerase chain reaction (RT-PCR), Primary culture of human fetal epiphyseal chondrocytes (HFEC) maintained V EGF expression at protein and messenger RNA (mRNA) levels and this expressi on was stimulated by cartilage-promoting growth factors incorporated into t he culture media (rFGF-b, rTGF-beta 1, and insulin-like growth factor [rIGF -I] at 50 ng/ml), The conditioned medium (CM) of HFEC stimulated the prolif eration of endothelial cells, and this was partially blocked by anti-VEGF a ntibody. These studies showed VEGF production by chondrocytes of the epiphy seal growth cartilage and suggested a role of this factor in cartilage phys iology and the angiogenic process.