Isolation of Stem Cells, Endothelial Cells and Pericytes from Human Infantile Hemangioma

Infantile hemangioma (IH) is a vascular tumor noted for its excessive blood vessel formation during infancy, glucose-transporter-1 (GLUT1)-positive staining of the blood vessels, and its slow spontaneous involution over several years in early childhood. For most children, IH poses no serious threat because it will eventually involute, but a subset can destroy facial structures and impair vision, breathing and feeding. To unravel the molecular mechanism(s) driving IH-specific vascular overgrowth, which to date remains elusive, investigators have studied IH histopathology, the cellular constituents and mRNA expression. Hemangioma endothelial cells (HemEC) were first isolated from surgically removed IH specimens in 1982 by Mulliken and colleagues ( Mulliken et al., 1982 ). Hemangioma stem cells (HemSC) were isolated in 2008, hemangioma pericytes in 2013 and GLUT1-positive HemEC in 2015. Indeed, as we describe here, it is possible to isolate HemSC, GLUT1-positive HemEC, GLUT1-negative HemEC and HemPericytes from a single proliferating IH tissue specimen. This is accomplished by sequential selection using antibodies against specific cell surface markers: anti-CD133 to select HemSC, anti-GLUT1 and anti-CD31 to select HemECs and anti-PDGFRβ to select HemPericytes. IH-derived cells proliferate well in culture and can be used for in vitro and in vivo vasculogenesis and angiogenesis assays.