Angiogenesis versus arteriogenesis.

In the vascular system, angiogenesis and arteriogenesis play a unique yet equally important role in both health and disease. Angiogenesis, the formation of new blood vessels from a preexisting vascular bed, occurs naturally during wound healing, the female menstrual cycle and pregnancy. It plays a critical role in tissue growth and repair, and is a highly controlled process that is dependent on an intricate balance of both pro-angiogenic (to stimulate) and anti-angiogenic (to negatively regulate the phenomenon) factors. Otherwise, the term arteriogenesis refers to anatomic transformation of preexisting arterioles with increasing lumen area and wall thickness, due to a thick muscular layer and purchasing of visco-elastic and vasomotor capacities. Arteriogenesis differs from angiogenesis in several aspects, the most important being the dependence of angiogenesis on hypoxia and the dependence of arteriogenesis on inflammation. The expression of growth factors and the cooperation of surrounding and infiltrating cells seem to be essential in orchestrating the complex processes during arteriogenesis.