Acidic fibroblast growth factor (aFGF), basic fibroblast growth factor
(bFGF), transforming growth factor alpha (TGF-alpha), transforming gr
owth factor beta (TGF-beta), epidermal growth factor (EGF), vascular e
ndothelial growth factor (VEGF(165)), tumor necrosis factor alpha (TNF
-alpha), and platelet-derived growth factor BE (PDGF-BB) were incorpor
ated into slow release polymers and implanted in the rabbit cornea as
an assay for angiogenesis activity. VEGF and low doses of PDGF-BB were
direct angiogenesis factors, stimulating endothelial cells to form ca
pillaries in the absence of inflammation. TGF-beta was an indirect ang
iogenesis factor, eliciting angiogenesis through the recruitment of in
flammatory cell mediators. TGF-alpha and EGF were ''bifunctional'' ang
iogenesis factors. Both factors recruited inflammatory cells prior to
angiogenesis, but when the inflammation was blocked, angiogenesis stil
l proceeded, Acidic FGF, bFGF and TNF-alpha were non-angiogenic.