title: Quantitative study of tissue-engineered cartilage with human bone marrow mesenchymal stem cells.
abstract: OBJECTIVE
  To assess the possibility of cartilage tissue engineering using human mesenchymal stem cells (hMSCs) and to investigate the quantitative relationship between hMSCs and engineered cartilage.
  
  
  METHODS
  Human mesenchymal stem cells were cultured, cryopreserved, and expanded in vitro. Surface antigens were detected by flow cytometry. In vitro chondrogenesis of hMSCs and cryopreserved hMSCs was performed. The chondrogenesis-induced hMSCs were seeded onto polyglycolic acid scaffolds, cultured in vitro for 3 weeks in chondrogenic medium, and then implanted into nude mice. The implants were harvested after 10 weeks and examined with histologic and immunochemical staining.
  
  
  RESULTS
  The construction of cartilages was identified grossly and histologically: 1.9 to 2.5 x 10(7) nucleated cells were obtained from 1 mL of bone marrow, and about 1 to 2 x 10(6) hMSCs were obtained from the primary culture. The number of hMSCs tripled at every passage and reached 1.4 to 2.8 x 10(12) at passage 15. The purity of hMSCs was 95% and 98% at the primary and the fourth passages, respectively. Twenty-one days was the optimal (induction rate, 95%) induction time, with no apparent differences in induction rates among different passages. Based on our findings, hMSCs from 0.07 to 0.14 mL of bone marrow, expanded during 4 passages and induced for 21 days, would be sufficient to engineer 1 cm(2) of cartilage, 3-mm thick.
  
  
  CONCLUSIONS
  Quantitative standards of hMSCs as seed cells for cartilage tissue engineering were established and may have value for later clinical work.
authors.affiliation: Department of Otorhinolaryngology, TangDu Hospital, The Fourth Military Medical University, Xi'an, People's Republic of China. pangyg@fmmu.edu.cn
authors.forename: Yonggang
authors.initials: Y
authors.lastname: Pang
authors.forename: Pengcheng
authors.initials: P
authors.lastname: Cui
authors.forename: Wenxian
authors.initials: W
authors.lastname: Chen
authors.forename: Pengfei
authors.initials: P
authors.lastname: Gao
authors.forename: Huizhong
authors.initials: H
authors.lastname: Zhang
mesh_terms: D000818:Animals; D001854:Bone Marrow Cells / Q000166:cytology*; D002356:Cartilage / Q000166:cytology*; D018929:Cell Culture Techniques; D020219:Chondrogenesis / Q000502:physiology; D006801:Humans; D059630:Mesenchymal Stem Cells / Q000166:cytology*; D051379:Mice; D008819:Mice, Nude; D023822:Tissue Engineering / Q000379:methods*