title: Secretory osteocalcin as a nondestructive osteogenic marker of tissue-engineered bone.
abstract: OBJECTIVE
  The constructs of mesenchymal stem cells and ceramics form bone tissue after implantation. Therefore, the constructs can include cultured bone (tissue-engineered bone) as bone grafts. However, the selection of constructs, prior to implantation, with high osteogenic potential is still difficult. We used a rat model to measure the secretory osteocalcin level in culture medium to verify that monitoring osteocalcin levels enables the selection of constructs with high osteogenic potential.
  
  
  METHODS
  We prepared constructs of rat hydroxyapatite/cells and used different cell passages of P-1 and P-3 as well as different cell numbers: 1 × 10(5) and 1 × 10(6) cells/ml suspension. These constructs were cultured for 14 days under osteoinductive or nonosteoinductive conditions and implanted subcutaneously in the recipient rat. Secretory osteocalcin in the culture medium was measured using an enzyme-linked immunosorbent assay system during the culture period until day 14, and the osteocalcin content of the harvested construct at 4 weeks was also measured.
  
  
  CONCLUSIONS
  All constructs except the hydroxyapatite/P-3 construct showed abundant bone formation by histology and both high secretory osteocalcin level in the medium and high osteocalcin content after implantation. Our study revealed that secretory osteocalcin level in vitro was related to osteocalcin content in vivo. The study clearly showed that measuring secretory osteocalcin is a nondestructive method of assessing the osteogenic potential of tissue-engineered bone. One can choose tissue-engineered bone with high osteogenic potential by integrating secretory osteocalcin measurement into the process of bone-tissue regeneration.
authors: Department of Public Health, Health Management and Policy, Nara Medical University School of Medicine, Shijo-cho 840, Kashihara, Nara, 634-8521, Japan. makahane@naramed-u.ac.jp
authors: Manabu
authors: M
authors: Akahane
authors: Tomoyuki
authors: T
authors: Ueha
authors: Yoshiko
authors: Y
authors: Dohi
authors: Takamasa
authors: T
authors: Shimizu
authors: Yasuaki
authors: Y
authors: Tohma
authors: Akira
authors: A
authors: Kido
authors: Kenji
authors: K
authors: Kawate
authors: Tomoaki
authors: T
authors: Imamura
authors: Yasuhito
authors: Y
authors: Tanaka
mesh_terms: D000818:Animals; D001842:Bone and Bones / Q000502:physiology*; D018929:Cell Culture Techniques; D017886:Durapatite; D008297:Male; D023421:Models, Animal; D015675:Osteocalcin / Q000378:metabolism*; D010012:Osteogenesis / Q000502:physiology*; D051381:Rats; D011916:Rats, Inbred F344; D023822:Tissue Engineering; D054457:Tissue Scaffolds
chemical_list: D015675:Osteocalcin; D017886:Durapatite