Integrins in vascular development

Many growth factors and their protein kinase receptors play a role in regul ating vascular development. In addition, cell adhesion molecules, such as i ntegrins and their ligands in the extracellular matrix, play important role s in the adhesion, migration, proliferation, survival and differentiation o f the cells that form the vasculature. Some integrins are known to be regul ated by angiogenic growth factors and studies with inhibitors of integrin f unctions and using strains of mice lacking specific integrins clearly impli cate some of these molecules in vasculogenesis and angiogenesis. However, t he data are incomplete and sometimes discordant and it is unclear how angio genic growth factors and integrin-mediated adhesive events cooperate in the diverse cell biological processes involved in forming the vasculature. Con sideration of the results suggests working hypotheses and raises questions for future research directions.