Abstract 17290: Stimulation of Angiogenesis by Mesenchymal Stem Cells: Paracrine and Autocrine Roles of SLIT3

Introduction: Mesenchymal stem cells (MSCs) are being developed as proangiogenic agents. However, clinical experience with MSCs is equivocal, and it is unknown if (and why) MSCs from different tissues promote angiogenesis to differing degrees. In an effort to resolve this issue, we examined the angiogenic potential of bone marrow-derived vs thymus-derived MSCs. Methods: Human neonatal thymus MSCs were compared to subject-matched and unrelated adult bone MSCs. Expression of pericyte markers/genes were evaluated, and angiogenic potency determined in vitro by assessing endothelial cell (EC) tubule formation, spheroid sprouting, angiogenic growth factor expression as well as in vivo using a subcutaneous implant model. Transcriptome differences in subject-matched thymus and bone MSCs were determined by microarray and Western blotting. Downstream gain/loss of function experiments were then performed. Results: MSCs from both tissue types displayed similar expression of pericyte surface markers, but thymus MSCs h...