Controlled release of stromal-cell-derived factor-1 from gelatin hydrogels enhances angiogenesis.

Controlled release of a chemokine, stromal-cell-derived factor-1 (SDF-1), could be achieved with gelatin hydrogels of release carrier. Gelatin was chemically derivatized to give it different electric charge and hydrophobicity. Among the derivatives, succinylated gelatin (Succ) of an anionic charge was the most suitable for preparation of the hydrogel in terms of SDF-1 release. The time profile of SDF-1 release from the hydrogel of succinylated gelatin could be controlled by changing the water content of hydrogel which could be modified by changing the conditions of hydrogel preparation. When evaluated after the subcutaneous implantation of Succ hydrogels incorporating SDF-1 or injection of SDF-1 solution, significantly stronger angiogenesis by the hydrogel was observed. The hydrogel implantation also enhanced the mRNA level of SDF-1 receptor at the site implanted. It is possible that the gelatin hydrogel enabled SDF-1 to be released locally, resulting in an enhanced angiogenesis at the site implanted.