TITLE:
Use of Cryopreserved Osteogenic Matrix Cell Sheets for Bone Reconstruction
AUTHORS:
Tomohiko Kura, Manabu Akahane, Takamasa Shimizu, Yoshinobu Uchihara, Yasuaki Tohma, Yusuke Morita, Munehisa Koizumi, Kenji Kawate, Yasuhito Tanaka
KEYWORDS:
Bone Marrow Stromal Cell, Cryopreservation, Cell Sheet, Injectable Bone, Bone Reconstruction
JOURNAL NAME:
Stem Cell Discovery,
Vol.6 No.1,
January
8,
2016
ABSTRACT: Skeletal diseases, such as nonunion and osteonecrosis, are now treatable with tissue engineering techniques. Single cell sheets called osteogenic matrix cell sheets (OMCSs) grown from cultured bone marrow-derived mesenchymal stem cells show high osteogenic potential; however, long preparation times currently limit their clinical application. Here, we report a cryopreservation OMCS transplantation method that shortens OMCS preparation time. Cryopreserved rat OMCSs were prepared using slow- and rapid-freezing methods, thawed, and subsequently injected scaffold-free into subcutaneous sites. Rapid- and slow-frozen OMCSs were also transplanted directly to the femur bone at sites of injury. Slow-freezing resulted in higher cell viability than rapid freezing, yet all two cryopreservation methods yielded OMCSs that survived and formed bone tissue. In the rapid- and slow-freezing groups, cortical gaps were repaired and bone continuity was observed within 6 weeks of OMCS transplantation. Moreover, while no significant difference was found in osteocalcin expression between the three experimental groups, the biomechanical strength of femurs treated with slow-frozen OMCSs was significantly greater than those of non-transplant at 6 weeks post-injury. Collectively, these data suggest that slow-frozen OMCSs have superior osteogenic potential and are better suited to produce a mineralized matrix and repair sites of bone injury.