1. Department of Orthopedic Surgery, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, N15W7, Sapporo 060-8638, Japan
2. PuREC/Bio-Venture, Shimane University, Izumo 693-8501, Japan
3. Japan Tissue Engineering Co., Ltd. (J-TEC), Gamagori 443-0022, Japan
4. Department of Advanced Medicine for Spine and Spinal Cord Disorders, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, N15W7, Sapporo 060-8638, Japan