Characterization of endothelial-like cells derived from human mesenchymal stem cells

Abstract

Background: Blood-derived endothelial progenitor cells (EPC) have been used to treat ischemic disease. However, the number of EPC that can be obtained from adult blood is limited. Objective: To characterize endothelial-like cells obtained from human bone marrow and determine their ability to stimulate new blood vessel formation in vivo. Methods: Mononuclear cells (MNC) were isolated from human bone marrow or umbilical cord blood and cultured in endothelial growth medium (EGM-2). Mesenchymal stem cells (MSC) were isolated from bone marrow and induced to differentiate into endothelial-like cells (MSCE), or adipocytes or osteocytes by growth in EGM-2, adipogenic or osteogenic medium. Results: Cells obtained by culturing bone marrow MNC in EGM-2 formed cord- or tube-like structures when grown on Matrigel TM and expressed several endothelial marker proteins. However, cell morphology and the profile of endothelial marker protein expression were different from those of cord blood-derived EPC (cbEPC). Cells with a similar phenotype were obtained by differentiation of MSC into MSCE, which was accompanied by an increase of endothelial marker proteins and a diminished capacity to differentiate into adipocytes. Subcutaneous implantation of MSCE in collagen plugs in non-obese diabetic-severe combined immunodeficient (NOD-SCID) mice resulted in formation of functional blood vessels that had incorporated the MSCE. Conclusion: Our results show that MSCE and cbEPC are different cell types. The formation of functional blood vessels by MSCE, combined with high yields and a reduced capacity to differentiate into other cell types compared with MSC, makes these cells potentially useful for autologous therapy of ischemic disease. © 2007 International Society on Thrombosis and Haemostasis.