Treatment of chronic wounds: state of the art and future concepts.

The morbidity and mortality from chronic wounds of varying etiology present a significant health care problem. Multiple local disturbances and systemic disease can impair wound healing. Recently, experiments with tissue cultures and animal models have revolutionized the understanding of wound healing and the pathophysiological processes involved. In cooperation with clinicians and industrial partners novel therapeutic concepts including the topical application of growth factors and cell therapies have been developed. Cytokines that have been tested in clinical studies include epidermal growth factor, platelet-derived growth factor and fibroblast growth factor. These studies showed that an important aspect of the growth factor wound healing paradigm is the effective delivery of these polypeptides to the wound site. Current drug delivery strategies suffer from the inherent loss of drug activity due to the combined effects of physical inhibition and biological degradation. A molecular genetic approach in which genetically modified cells synthesize and deliver the desired growth factor in a time-regulated manner is a powerful means to overcome the limitations associated with the topical application of recombinant growth factor proteins.