Inagaki Y, Akahane M, Shimizu T, Inoue K, Egawa T, Kira T, Ogawa M, Kawate K, Tanaka Y. Modifying oxygen tension affects bone marrow stromal cell osteogenesis for regenerative medicine. World J Stem Cells 2017; 9(7): 98-106 [PMID: 28785381 DOI: 10.4252/wjsc.v9.i7.98]
Corresponding Author of This Article
Yusuke Inagaki, MD, PhD, Assisstant Professor, Department of Orthopedic Surgery, Nara Medical University, 840 Shijo-cho, Kashihara, Nara 634-8522, Japan. yinagaki@naramed-u.ac.jp
Research Domain of This Article
Orthopedics
Article-Type of This Article
Basic Study
Open-Access Policy of This Article
This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Yusuke Inagaki, Takamasa Shimizu, Kazuya Inoue, Takuya Egawa, Tsutomu Kira, Munehiro Ogawa, Yasuhito Tanaka, Department of Orthopedic Surgery, Nara Medical University, Kashihara, Nara 634-8522, Japan
Manabu Akahane, Department of Public Health, Health Management and Policy, Nara Medical University, Faculty of Medicine, Kashihara, Nara 634-8521, Japan
Kenji Kawate, Departments of Artificial Joint and Regenerative Medicine for Bone and Cartilage, Nara Medical University, Kashihara, Nara 634-8522, Japan
Author contributions: Inagaki Y and Akahane M designed the study; Inagaki Y, Akahane M, Shimizu T, Inoue K, Egawa T and Kira T performed the study; Inagaki Y and Akahane M drafted the manuscript; Ogawa M, Kawate K and Tanaka Y critically reviewed the draft; all authors read and approved the final manuscript.
Institutional review board statement: This study was approved by the Institutional Review Board of Nara Medical University before beginning experiments.
Institutional animal care and use committee statement: All experimental protocols using animals were approved by the Animal Experimental Review Board of Nara Medical University before beginning experiments.
Conflict-of-interest statement: There is no conflict of interest regarding to this study.
Data sharing statement: None.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Yusuke Inagaki, MD, PhD, Assisstant Professor, Department of Orthopedic Surgery, Nara Medical University, 840 Shijo-cho, Kashihara, Nara 634-8522, Japan. yinagaki@naramed-u.ac.jp
Telephone: +81-744-223051 Fax: +81-744-256449
Received: January 26, 2017 Peer-review started: February 2, 2017 First decision: March 31, 2017 Revised: April 27, 2017 Accepted: June 6, 2017 Article in press: June 8, 2017 Published online: July 26, 2017 Processing time: 171 Days and 15.6 Hours
Abstract
AIM
To establish a hypoxic environment for promoting osteogenesis in rat marrow stromal cells (MSCs) using osteogenic matrix cell sheets (OMCSs).
METHODS
Rat MSCs were cultured in osteogenic media under one of four varying oxygen conditions: Normoxia (21% O2) for 14 d (NN), normoxia for 7 d followed by hypoxia (5% O2) for 7 d (NH), hypoxia for 7 d followed by normoxia for 7 d (HN), or hypoxia for 14 d (HH). Osteogenesis was evaluated by observing changes in cell morphology and calcium deposition, and by measuring osteocalcin secretion (ELISA) and calcium content. In vivo syngeneic transplantation using OMCSs and β-tricalcium phosphate discs, preconditioned under NN or HN conditions, was also evaluated by histology, calcium content measurements, and real-time quantitative PCR.
RESULTS
In the NN and HN groups, differentiated, cuboidal-shaped cells were readily observed, along with calcium deposits. In the HN group, the levels of secreted osteocalcin increased rapidly from day 10 as compared with the other groups, and plateaued at day 12 (P < 0.05). At day 14, the HN group showed the highest amount of calcium deposition. In vivo, the HN group showed histologically prominent new bone formation, increased calcium deposition, and higher collagen type I messenger RNA expression as compared with the NN group.
CONCLUSION
The results of this study indicate that modifying oxygen tension is an effective method to enhance the osteogenic ability of MSCs used for OMCSs.
Core tip: Bone tissue engineering using marrow stromal cells (MSCs) is a promising method in regenerative medicine. Here, we have reported a scaffold-free transplantation technique using hypoxic-preconditioned osteogenic matrix cell sheets (OMCSs) derived from MSCs. We show that modifying the oxygen tension before implantation of OMCS composites led to an increased osteogenic capacity of rat bone MSCs.
