Extracellular matrix as a strategy for treating chronic wounds.

The dermis normally directs all phases of skin wound healing following tissue trauma or disease. However, in chronic wounds, the dermal matrix is insufficient to stimulate healing and assistance by external factors is needed for wound closure. Although the concept of the extracellular matrix directing wound healing is not new, ideas about how best to provide the extracellular matrix components required to 'jump-start' the healing process are still evolving. Historically, these strategies have included use of enzyme-inhibiting dressing materials, which bind matrix metalloproteinases and remove them from the chronic wound environment, or direct application of purified growth factors to stimulate fibroblast activity and deposition of neo-matrix. More recently, the application of a structurally intact, biochemically complex extracellular matrix, designed to provide the critical extracellular components of the dermis in a single application, has allowed for the reconstruction of new, healthy tissue and restoration of tissue integrity in the previously chronic wound. This review focuses on this third mechanism as an emerging tactic in effective wound repair. Intact extracellular matrix can quickly, easily, and effectively provide key extracellular components of the dermis necessary to direct the healing response and allow for the proliferation of new, healthy tissue. Its application may promote the healing of wounds that have been refractory to other, more conventional treatment strategies, and may eventually show utility when used earlier in wound healing treatment with the goal of preventing wounds from reaching a truly chronic, nonresponsive state.