Growth factors and the vessel wall

The vascular tree is a highly specialized organ that has developed a complex and highly orchestrated mechanism of response to injury and stress. After PTCA-like injury many of these mechanisms are activated to maintain vessel integrity. Similar but clearly different growth mechanisms are activated by hypertension and hemodynamic stress. In this light, restenosis is merely a reparative response that has gone on too long or to a greater extent than necessary. The number of growth factors that affect this system is enormous, and their temporal and spatial distribution suggests that therapy targeted to any single factor is unlikely to be successful. In contrast, therapies directed at common mediators such as extracellular matrix and downstream cellular effectors may be more effective. Increasing knowledge of these interactions should point the way to new therapies based on cell-cell and cell-matrix interactions that are tissue specific and focused in time and that take advantage of the common mechanisms by which vessels normally adapt to stress.