Effect of heparin on the angiogenic potency of basic and acidic fibroblast growth factors in the rabbit cornea assay.

One of the aims of this study was to demonstrate that basic fibroblast growth factor (bFGF), purified to homogeneity, could enhance angiogenesis in vivo by a dose-dependent relationship in the rabbit cornea assay (half-maximum activity = 100 ng/pellet). Under our experimental conditions, the acidic factor (aFGF) did not show any significant effect on experimental angiogenesis at a concentration of 3.5 micrograms/pellet. However, when heparin (1 microgram/pellet) and acidic FGF (0.9 microgram/pellet) were co-incorporated within the same pellet, we could detect a high level of capillary proliferation. Moreover, this angiogenic effect could easily be compared with the activity of basic FGF (0.9 microgram/pellet) on its own. Under the conditions used, heparin did not alter basic FGF mitogenic activity. We suggest that, as occurs in vitro on human umbilical vein endothelial cells, heparin could stabilize acidic FGF in such a manner that it retains all its mitogenic activity in vivo.