Arteriogenesis, the good and bad of it.

Arteriogenesis, the process of collateral artery growth as an adaptation to major arterial occlusion, can be life- and tissue saving and may alter the natural course of the consequences and organ manifestations of arterial disease. This is achieved by an active growth process that is coupled to complete arterial remodeling with activation of proteases and destruction of the organ tissue in the immediate vicinity of the growing vessel, to create the space for a new artery which expands to about 20 times its original diameter. Much of the growth and remodeling is achieved by attraction, adhesion, activation and invasion of circulating cells, mostly monocytes, but also T-cells and basophiles. Growth factors that are already present, as well as those that are produced by invading cells, produce an environment of inflammation and facilitate coagulation and are therefore pro-atherogenic. It will be a challenge for future therapies with growth factors, chemokines and cytokines to neutralize the atherogenic and to maximize their arteriogenic properties.