%0 Journal Article %T Detection of the Hematopoietic Stem and Progenitor Cell Marker CD133 during Angiogenesis in Three-Dimensional Collagen Gel Culture %A Masumi Akita %A Kayoko Tanaka %A Sachiko Matsumoto %A Kumiko Komatsu %A Keiko Fujita %J Stem Cells International %D 2013 %I Hindawi Publishing Corporation %R 10.1155/2013/927403 %X We detected the hematopoietic stem and progenitor cell marker CD133 using immunogold labeling during angiogenesis in a three-dimensional collagen gel culture. CD133-positive cells were present in capillary tubes newly formed from aortic explants in vitro. The CD133-positive cell population had the capacity to form capillary tubes. Lovastatin strongly inhibited cell migration from aortic explants and caused the degradation of the capillary tubes. The present study provides insight into the function of CD133 during angiogenesis as well as an explanation for the antiangiogenic effect of statins. 1. Introduction CD133 was first isolated and cloned in 1997. CD133 expression was originally observed in hematopoietic stem and progenitor cells using a monoclonal antibody called AC133 [1] and neuroepithelial cells using a monoclonal antibody called prominin [2]. Gehling et al. [3] reported that the CD133-positive cell population consists of progenitor and stem cells that not only have hematopoietic potential but also have the capacity to differentiate into endothelial cells. Invernici et al. [4] reported that human fetal aorta contains vascular progenitor cells capable of inducing vasculogenesis and angiogenesis. Barcelos et al. [5] reported that human CD133 progenitor cells promote the healing of diabetic ischemic ulcers by paracrine stimulation of angiogenesis and activation of Wnt signaling. To grow, solid tumors require a blood supply. They recruit new blood vessels mainly by inducing the sprouting of endothelial cells from external vessels. Recent research in tumor biology shows that, in addition to recruiting vessels from outside the tumor, brain tumors produce endothelial cells for vessel formation within the tumor [6]. Wang et al. [7] reported that a glioblastoma cell population (CD144 and CD133 double positive) differentiated into endothelial cells and formed intracellular vacuolar structures in collagen gel. However, the biological function of CD133 in angiogenesis remains largely unknown. For in vitro studies of angiogenesis, several culture techniques using matrix structures have been developed, including fibrin and collagen gels [8], Matrigel, collagen, fibrin, and plasma clots [9]. Collagen gel culture has been used widely and effectively for analyzing the biological process of angiogenesis [10¨C13]. Using a three-dimensional (3D) collagen gel culture, we have conducted electron microscopic studies [14, 15] and immunohistochemical studies of fibroblast growth factor- (FGF-) 2 and FGF-9 [16]. Additionally, we have used 3D collagen gel cultures to test %U http://www.hindawi.com/journals/sci/2013/927403/