The role of growth factors in the healing of chronic wounds.

The clinical use of growth factors for the treatment of nonhealing human wounds holds great therapeutic potential. However, numerous clinical studies of recombinant growth factors used to treat chronic dermal wounds have generally reported disappointing results. Part of the explanation for these results may be a lack of appreciation of three basic principles related to the biology of wound healing and pharmaceutic considerations. Above all, the growth factor selected for a particular nonhealing wound must regulate a process of healing which is predominantly involved in healing that wound. A growth factor which stimulates epithelialization will be of little good in a wound which needs to heal by connective tissue deposition. Once the appropriate biologic modifier has been identified, one must be assured that there is a deficiency of that modifier in the wound environment. Finally, one must be sure that the delivery of the growth factor to the wound is in sufficient amount and duration to produce a biologic response. These considerations are exemplified with several clinical studies which did show improvement in the rate of healing of chronic wounds. Only when clinical trials are undertaken in which these tenets are incorporated in the study design will the true potential of various growth factors be appropriately determined.