1. Stem Cell Research Center, Department of Orthopaedic Surgery, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15219, USA
2. Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15260, USA
3. Institute for Cell Engineering and Department of Pediatric Oncology, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
4. Centre for Regenerative Medicine, University of Edinburgh, Edinburgh, EH16 4TJ, UK
5. Orthopaedic Hospital Research Center and David Geffen School of Medicine at UCLA, University of California at Los Angeles, 615 Charles E. Young Drive South, Los Angeles, CA 90095-7358, USA
6. Cell Factory, Fondazione Ospedale Maggiore Policlinico, 20122 Milan, Italy
7. McGowan Institute for Regenerative Medicine, Pittsburgh, PA 15219, USA
8. Centre for Cardiovascular Science, University of Edinburgh, Queen’s Medical Research Institute, 47 Little France Crescent, Edinburgh EH16 4TJ, UK