Platelet-derived factors involved in tissue repair-from signal to function

Topical treatment with platelet derivatives has increasingly been described as being capable of accelerating wound healing and to aid in tissue repair. In vitro data indicate that platelets and their contents have chemotactic, migration-inducing, and mitogenic activities, and a major role of these factors in tissue repair has thus been advocated. However, how platelet-derived factors orchestrate tissue repair at the cellular level remains quite obscure even to those individuals who prescribe platelet derivatives as topical wound healing therapy. The primary objective of this review was to provide the practitioner, inexpert in biochemistry, an overview about signal transduction within cells in response to platelet-derived factors. Concepts from the literature were selected to illustrate how a relatively few units of information can be put together in specific order to allow for complex biologic functions to be elicited. To illustrate how functional complexity emerges from a narrow set of messengers, an analogy between signal transduction and language, or contrapunctual music, has been drawn.