Neoendothelialization after peripheral blood stem cell transplantation in humans: a case report of a Tokaimura nuclear accident victim.

Objectives: Neoendothelialization by circulating endothelial progenitor cells has been a topic of recent research. The extent and scale of this process in humans is not well understood. We examined the extent of neoendothelialization of the aorta and peripheral arteries in the case of a patient who underwent peripheral blood stem cell transplantation for acute radiation syndrome. Methods: Human tissue samples from the aorta and peripheral arteries were obtained at autopsy. Endothelial cells were isolated, confirmed by von Willebrand factor immunostaining, and then subjected to fluorescent in situ hybridization analysis using X- and Y-chromosome specific probes to examine neoendothelialization by donor cells as possible in this case in which the donor and recipient were of different genders. Results: The aorta showed almost 25% of all endothelial cells to be replaced by donor-origin endothelial cells. The peripheral arteries were also replaced but to a lesser extent. Discussion: The present study provides evidence that peripheral blood is a source of endothelial progenitor cells in humans. Neoendothelialization of the aorta occurs to a significant extent under certain conditions suggesting the potential for exploitation of therapeutic neovascularization by transplantation of circulating endothelial progenitor cells.