Angiogenesis in Wound Repair: Too Much of a Good Thing?

Angiogenesis, or the growth of new blood vessels from the preexisting vasculature, is a visible and important component of wound repair. When tissue damage occurs, disruption of the vasculature structure leads to hypoxia. The restoration of normoxia is essential for appropriate and durable tissue repair. Angiogenesis in wounds is regulated by endogenous proangiogenic mediators, which cause rapid growth of a new vascular bed that is much denser than that of normal tissue. Such rapid growth of the capillary bed results in capillaries that are abnormal, and the newly formed vessels are tortuous, dilated, and immature. During wound resolution, this substantial neocapillary bed is pruned back to normal density with attendant maturation. Many poorly healing wounds, including nonhealing ulcers and scars, exhibit an aberrant angiogenic response. The fine-tuning of capillary regrowth in wounds is an area of significant therapeutic potential.