title: Zone-specific integrated cartilage repair using a scaffold-free tissue engineered construct derived from allogenic synovial mesenchymal stem cells: Biomechanical and histological assessments.
abstract: The purpose of the present study was to investigate the zone-specific integration properties of articular cartilage defects treated in vivo with scaffold-free three-dimensional tissue-engineered constructs (TECs) derived from allogenic synovial mesenchymal stem cells (MSCs) in a porcine model. The TEC derived from the synovial MSCs was implanted into chondral defects in the medial femoral condyle of the knee. The integration boundary of repair tissue with the adjacent host cartilage was morphologically and biomechanically evaluated at 6 months post-implantation. Histological assessments showed that the repair tissue in each zone was well integrated with the adjacent host cartilage, with an apparent secure continuity of the extracellular matrix. There were no significant differences in histological scores between the integration boundary and the center of the repair tissue at every zone. Nonetheless, in all the specimens subjected to mechanical testing, failure occurred at the integration boundary. The average tensile strength of the integration boundary vs normal cartilage was 0.6 vs 4.9, 3.0 vs 12.6, and 5.5 vs 12.8MPa at the superficial, middle, and deep layers, respectively. Thus, these results indicate the most fragile point in the repair tissue remained at the integration boundary in spite of the apparent secure tissue continuity and equivalent histological quality with the center of the repair tissue. Such tissue vulnerability at the surface integration boundary could affect the long-term durability of the tissue repair, and thus, special consideration will be needed in the post-operative rehabilitation programming to enhance the longevity of such repair tissues in response to normal knee loading.
authors.affiliation: Faculty of System Design, Tokyo Metropolitan University, 6-6 Asahigaoka, Hino, Tokyo 191-0065, Japan; Research Institute for Science and Technology, Kogakuin University, Tokyo, Japan. Electronic address: fujie@tmu.ac.jp.
authors.forename: Hiromichi
authors.initials: H
authors.lastname: Fujie
authors.affiliation: Research Institute for Science and Technology, Kogakuin University, Tokyo, Japan.
authors.forename: Ryosuke
authors.initials: R
authors.lastname: Nansai
authors.affiliation: Department of Orthopaedics, Osaka University Graduate School of Medicine, Osaka, Japan.
authors.forename: Wataru
authors.initials: W
authors.lastname: Ando
authors.affiliation: Department of Orthopaedics, Osaka University Graduate School of Medicine, Osaka, Japan.
authors.forename: Kazunori
authors.initials: K
authors.lastname: Shimomura
authors.affiliation: Department of Orthopaedics, Osaka University Graduate School of Medicine, Osaka, Japan.
authors.forename: Yu
authors.initials: Y
authors.lastname: Moriguchi
authors.affiliation: McCaig Institute for Bone & Joint Health, Biomedical Engineering Program, University of Calgary, Calgary, Canada.
authors.forename: David A
authors.initials: DA
authors.lastname: Hart
authors.affiliation: Department of Orthopaedics, Osaka University Graduate School of Medicine, Osaka, Japan; Institute for Medical Science in Sports, Osaka Health Science University, Japan.
authors.forename: Norimasa
authors.initials: N
authors.lastname: Nakamura
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D002358:Cartilage, Articular / Q000293:injuries / Q000473:pathology / Q000503:physiopathology; D002478:Cells, Cultured; D005109:Extracellular Matrix / Q000637:transplantation; D006614:Hindlimb / Q000293:injuries; D007596:Joints / Q000293:injuries / Q000473:pathology / Q000503:physiopathology; D008297:Male; D045164:Mesenchymal Stem Cell Transplantation; D059630:Mesenchymal Stem Cells / Q000502:physiology*; D034421:Sus scrofa; D023822:Tissue Engineering / Q000379:methods; D054457:Tissue Scaffolds; D014945:Wound Healing
keywords: Cartilage repair; Mesenchymal stem cells; Scaffold-free construct; Tissue engineering; Zone-specific integration