Secretory osteocalcin as a nondestructive osteogenic marker of tissue-engineered bone

• Published in: Journal of orthopaedic science : official journal of the Japanese Orthopaedic Association Vol. 16; no. 5; pp. 622 - 628
• Main Authors: Akahane, Manabu, Dohi, Yoshiko, Imamura, Tomoaki, Ueha, Tomoyuki, Shimizu, Takamasa, Tohma, Yasuaki, Kido, Akira, Tanaka, Yasuhito, Kawate, Kenji
• Format: Journal Article
• Language: English
• Published: Japan Elsevier B.V 01.09.2011; Springer Japan; Springer Nature B.V
• Subjects: Animals; Bone and Bones - physiology; Cell Culture Techniques; Durapatite; Male; Medicine; Medicine & Public Health; Models, Animal; Original Article; Orthopedics; Osteocalcin - secretion; Osteogenesis - physiology; Rats; Rats, Inbred F344; Rheumatology; Tissue Engineering; Tissue Scaffolds; Nondestructive Method; Polystyrene Dish; Subcutaneous Site; Bone Formation; Osteogenic Potential
• ISSN: 0949-2658; 1436-2023
• DOI: 10.1007/s00776-011-0121-8

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. 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 × 105 and 1 × 106 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. 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.