title: Contribution of circulating vascular progenitors in lesion formation and vascular healing: lessons from animal models.
abstract: OBJECTIVE
  It is a widely accepted view that vascular repair results from migration and proliferation of adjacent cells in animal models. On the contrary, accumulating evidence suggests that bone marrow can give rise to endothelial-like cells and smooth muscle like cells that potentially contribute to vascular healing, remodeling, and lesion formation under physiological and pathological conditions. The aim of this article is to review recent findings obtained from animal models of vascular diseases regarding bone marrow derived progenitor cells.
  
  
  RESULTS
  Studies using chimeric animals revealed that bone marrow derived cells exist at the sites of vascular healing and lesion formation after injury. High-resolution histological analyses revealed that those bone marrow derived cells do express some markers for endothelial cells or smooth muscle cells. Peripheral mononuclear cells could differentiate into endothelial-like cells or smooth muscle like cells in vitro according to the culture conditions.
  
  
  CONCLUSIONS
  Circulating progenitors significantly contribute to vascular repair and lesion formation. These findings provide the basis for the development of new therapeutic strategies that involve targeting the mobilization, homing, differentiation, and proliferation of bone marrow- derived vascular progenitor cells.
authors.affiliation: Department of Cardiovascular Medicine, University of Tokyo Graduate School of Medicine, Tokyo, Japan.
authors.forename: Kimie
authors.initials: K
authors.lastname: Tanaka
authors.forename: Masataka
authors.initials: M
authors.lastname: Sata