Angiogenesis and Pathogenesis of Port Wine Stain and Infantile Hemangiomas

Abstract

This chapter focuses on the angiogenesis and vasculogenesis involved in the pathophysiological processes and treatments of two common congenital vascular anomalies, namely port wine stain (PWS) and infantile hemangiomas (IH). PWS occur as pink/red macules in childhood but darken progressively to purple with subsequent skin thickening and the development of vascular nodules. Dilatation of postcapillary venules in PWS is likely caused by a deficiency of local nerve innervation. Although the pulsed dye laser has revolutionized PWS treatment, complete clearance is rarely achieved due to regrowth and reperfusion of injured blood vessels. Angiogenic signaling pathways activated after laser exposure will be discussed and the animal and clinical results of a new therapeutic strategy for PWS, combined laser exposure and administration of an anti-angiogenic agent will be presented. IH are tumors of infancy with a unique life cycle characterized by rapid proliferation followed by slow spontaneous involution. Phase-specific markers have been identified, including GLUT-1 and more recently indoleamine 2,3-dioxygenase associated with involution. The current understanding of the pathogenesis includes a close relationship with placental origin, role of hypoxia in stimulating development and somatic mutations in early development of the tumors.