Update on therapeutic neovascularization.

Therapeutic neovascularization for cardiovascular ischemia is a promising avenue in spite of disappointing early clinical trial results. The concept of three different mechanisms of neovascularization has served to define potential therapeutic targets such as vascular remodeling and stem cell recruitment, but it is anticipated that this will lose significance as the pleiotropic nature of angiogenic cytokines becomes fully understood. With the rapidly growing body of data on growth factors and pro-angiogenic strategies, approaches will emerge that are more effective than the ones that have been tested clinically thus far. Combinations of growth factors, for instance to stabilize vessels, or growth factors combined with cell transplants deserve more attention but will make the design of preclinical and clinical studies increasingly complex. Recent developments suggest that when using the appropriate dose and treatment regimens, even single growth factor therapy can result in stable and functional vessels. Whether gene therapy or protein therapy will be optimal for this purpose depends mainly on technical developments in vector design and production and on progress in the engineering of slow release matrix formulations for proteins. With the increasing complexity of therapeutic strategies, it remains imperative that these approaches are rationally based on fundamental and preclinical data.