Collagenous matrices as release carriers of exogenous growth factors.

We have investigated the use of natural and synthetic collagenous matrices as carriers of exogenous growth factors. A bladder acellular matrix (BAM) was processed from rat bladder and compared with sponge matrix of porcine type 1 collagen. The lyophilized matrices were rehydrated by the aqueous solutions of basic fibroblast growth factor (bFGF), hepatocyte growth factor (HGF), platelet derived growth factor-BB (PDGF-BB), vascular endothelial growth factor (VEGF), insulin like growth factor-1 (IGF-1) and heparin binding epidermal growth factor-like growth factor (HB-EGF), to obtain the matrix incorporating each growth factor. The rehydration method enabled the growth factor protein to distribute into the matrix homogeneously. In vivo release test in the mouse subcutis revealed that, the property of BAM for growth factor release was similar to that of collagen sponge. Among the growth factors examined, bFGF release was the most sustained, followed by HGF and PDGF-BB. bFGF released from the two matrices showed similar in vivo angiogenic activity at the mouse subcutis in a dose-dependent manner. These findings demonstrate that the collagenous matrices function as release carriers of growth factors. This feature is promising to create a scaffold, which has a nature to control the tissue regeneration actively.