1. a Wake Forest Institute for Regenerative Medicine, Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, North Carolina, USA
2. b Virginia Tech-Wake Forest School of Biomedical Engineering and Sciences, Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, North Carolina, USA
3. c Department of Urology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, People's Republic of China
4. d Department of Rehabilitation Medicine, Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, Washington, USA