The Experts below are selected from a list of 6540 Experts worldwide ranked by ideXlab platform

Norimasa Nakamura - One of the best experts on this subject based on the ideXlab platform.

  • enhanced repair of meniscal hoop structure injuries using an aligned electrospun nanofibrous scaffold combined with a mesenchymal stem cell derived tissue Engineered Construct
    Biomaterials, 2019
    Co-Authors: Kazunori Shimomura, Norimasa Nakamura, David A. Hart, Hideki Yoshikawa, Benjamin B Rothrauff, Shuichi Hamamoto, Masato Kobayashi, Rocky S Tuan
    Abstract:

    Abstract Damage to the meniscal hoop structure results in loss of biomechanical function, which potentially leads to the extrusion of the meniscus from the weight bearing area. However, there have been no established, effective treatments for such injuries. The purpose of this study was to investigate the applicability of cell-seeded nanofibrous scaffolds to repair the damaged meniscal hoop structure along with the prevention of subsequent cartilage degeneration using a rabbit model. Meniscal radial defects (5 mm width) in the medial meniscus were treated by wrapping and suturing with either an aligned electrospun nanofibrous scaffold alone or a scaffold combined with a tissue Engineered Construct (TEC) derived from synovial mesenchymal stem cells (MSCs), with the scaffold fiber direction matching that of the meniscal circumferential fibers. The MSC-based TEC-combined nanofibrous scaffolds contributed significantly to the prevention of meniscal extrusion and exerted a chondroprotective effect, compared with either scaffold alone or the untreated control groups. Also, meniscal defects treated with such TEC-combined nanofibrous scaffolds were consistently repaired with a fibrocartilaginous tissue. In this study, we have demonstrated the feasibility of a combined TEC-nanofibrous scaffold to repair the meniscal hoop structure, and prevent the progression to cartilage degeneration, as a potential tissue engineering method.

  • Osteochondral Repair Using a Hybrid Implant Composed of Stem Cells and Biomaterial
    Bio-orthopaedics, 2017
    Co-Authors: Kazunori Shimomura, David A. Hart, Hiromichi Fujie, Hideki Yoshikawa, Norimasa Nakamura
    Abstract:

    Osteoarthritis (OA) is a common disease, which could potentially affect the quality of life of both young and elderly populations worldwide. The management of OA remains challenging and controversial. Although there are several clinical options for the treatment of OA, it has proven difficult to restore the damaged articular cartilage due to the limited healing capacity. With the advancements in tissue engineering approaches including cell-based technologies and development of biomaterial scaffolds over the past decade, new therapeutic options for patients with osteochondral lesions may be potentially available. This chapter will highlight the current techniques and recent advances of tissue-Engineered biomaterial scaffolds, which can mimic the native osteochondral complex, for osteochondral tissue regeneration. Moreover, we will introduce our novel technique using a hybrid implant composed of artificial bone coupled with a mesenchymal stem cell (MSC)–based scaffold-free tissue-Engineered Construct (TEC) and show its feasibility for osteochondral repair.

  • zone specific integrated cartilage repair using a scaffold free tissue Engineered Construct derived from allogenic synovial mesenchymal stem cells biomechanical and histological assessments
    Journal of Biomechanics, 2015
    Co-Authors: Kazunori Shimomura, Norimasa Nakamura, David A. Hart, Hiromichi Fujie, Wataru Ando, Ryosuke Nansai, Yu Moriguchi
    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 12.8 MPa 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.

  • Frictional properties of articular cartilage-like tissues repaired with a mesenchymal stem cell-based tissue Engineered Construct
    2013 35th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 2013
    Co-Authors: Hiromichi Fujie, Norimasa Nakamura
    Abstract:

    We have been developing a novel tissue engineering technique for cartilage repair using a scaffold-free tissue Engineered Construct (TEC) bio-synthesized from synovium-derived mesenchymal stem cells (MSCs). In the present study, the effect of TEC on the repair of chondral defect in the femoral condyle of immature and mature pigs were investigated. The permeability of TEC-treated repaired tissues was significantly higher than normal level at surface layer in immature animals, while the permeability was slightly higher than normal level at middle and deep layers in mature animals. In immature animals, the coefficient of friction of TEC-treated tissues against a glass plate was load-dependently increased, with a significantly higher value than normal level observed at a high load (280 kPa). In contrast, the coefficient of friction was load-dependently decreased in mature animals, with no significant differences from normal level observed at all loads (70, 140, and 280 kPa). It is suggested that the frictional properties of TEC-treated cartilage-like repaired tissues are recovered to normal level in mature animals, while they are unrecovered to normal level due to underdeveloped, permeable surface layer in immature animals.

  • EMBC - Frictional properties of articular cartilage-like tissues repaired with a mesenchymal stem cell-based tissue Engineered Construct
    Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and, 2013
    Co-Authors: Hiromichi Fujie, Norimasa Nakamura
    Abstract:

    We have been developing a novel tissue engineering technique for cartilage repair using a scaffold-free tissue Engineered Construct (TEC) bio-synthesized from synovium-derived mesenchymal stem cells (MSCs). In the present study, the effect of TEC on the repair of chondral defect in the femoral condyle of immature and mature pigs were investigated. The permeability of TEC-treated repaired tissues was significantly higher than normal level at surface layer in immature animals, while the permeability was slightly higher than normal level at middle and deep layers in mature animals. In immature animals, the coefficient of friction of TEC-treated tissues against a glass plate was load-dependently increased, with a significantly higher value than normal level observed at a high load (280 kPa). In contrast, the coefficient of friction was load-dependently decreased in mature animals, with no significant differences from normal level observed at all loads (70, 140, and 280 kPa). It is suggested that the frictional properties of TEC-treated cartilage-like repaired tissues are recovered to normal level in mature animals, while they are unrecovered to normal level due to underdeveloped, permeable surface layer in immature animals.

Hiromichi Fujie - One of the best experts on this subject based on the ideXlab platform.

  • comparison of 2 different formulations of artificial bone for a hybrid implant with a tissue Engineered Construct derived from synovial mesenchymal stem cells a study using a rabbit osteochondral defect model
    American Journal of Sports Medicine, 2017
    Co-Authors: Kazunori Shimomura, David A. Hart, Hiromichi Fujie, Wataru Ando, Ryosuke Nansai, Shuji Horibe, Yu Moriguchi, Alberto Gobbi, Hideki Yoshikawa
    Abstract:

    Background:Previously, we developed a hybrid implant composed of hydroxyapatite (HA)–based artificial bone coupled with a mesenchymal stem cell (MSC)–based scaffold-free tissue-Engineered Construct (TEC) and demonstrated its feasibility for osteochondral repair. Beta-tricalcium phosphate (βTCP) may be a promising alternative to HA, as it is a highly biocompatible material and is resorbed more rapidly than HA in vivo.Hypothesis:A βTCP-based hybrid TEC implant will exhibit superior osteochondral repair when directly compared with an HA-based hybrid implant, as tested using a rabbit osteochondral defect model.Study Design:Controlled laboratory study.Methods:Osteochondral defects were created in the femoral groove of skeletally mature rabbits. The TEC and artificial bone, using either HA or βTCP with the same porosities and similar mechanical properties, were hybridized and then implanted in the defects. A histological evaluation and microindentation testing were performed for the assessment of repair tissue....

  • Osteochondral Repair Using a Hybrid Implant Composed of Stem Cells and Biomaterial
    Bio-orthopaedics, 2017
    Co-Authors: Kazunori Shimomura, David A. Hart, Hiromichi Fujie, Hideki Yoshikawa, Norimasa Nakamura
    Abstract:

    Osteoarthritis (OA) is a common disease, which could potentially affect the quality of life of both young and elderly populations worldwide. The management of OA remains challenging and controversial. Although there are several clinical options for the treatment of OA, it has proven difficult to restore the damaged articular cartilage due to the limited healing capacity. With the advancements in tissue engineering approaches including cell-based technologies and development of biomaterial scaffolds over the past decade, new therapeutic options for patients with osteochondral lesions may be potentially available. This chapter will highlight the current techniques and recent advances of tissue-Engineered biomaterial scaffolds, which can mimic the native osteochondral complex, for osteochondral tissue regeneration. Moreover, we will introduce our novel technique using a hybrid implant composed of artificial bone coupled with a mesenchymal stem cell (MSC)–based scaffold-free tissue-Engineered Construct (TEC) and show its feasibility for osteochondral repair.

  • zone specific integrated cartilage repair using a scaffold free tissue Engineered Construct derived from allogenic synovial mesenchymal stem cells biomechanical and histological assessments
    Journal of Biomechanics, 2015
    Co-Authors: Kazunori Shimomura, Norimasa Nakamura, David A. Hart, Hiromichi Fujie, Wataru Ando, Ryosuke Nansai, Yu Moriguchi
    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 12.8 MPa 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.

  • Frictional properties of articular cartilage-like tissues repaired with a mesenchymal stem cell-based tissue Engineered Construct
    2013 35th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 2013
    Co-Authors: Hiromichi Fujie, Norimasa Nakamura
    Abstract:

    We have been developing a novel tissue engineering technique for cartilage repair using a scaffold-free tissue Engineered Construct (TEC) bio-synthesized from synovium-derived mesenchymal stem cells (MSCs). In the present study, the effect of TEC on the repair of chondral defect in the femoral condyle of immature and mature pigs were investigated. The permeability of TEC-treated repaired tissues was significantly higher than normal level at surface layer in immature animals, while the permeability was slightly higher than normal level at middle and deep layers in mature animals. In immature animals, the coefficient of friction of TEC-treated tissues against a glass plate was load-dependently increased, with a significantly higher value than normal level observed at a high load (280 kPa). In contrast, the coefficient of friction was load-dependently decreased in mature animals, with no significant differences from normal level observed at all loads (70, 140, and 280 kPa). It is suggested that the frictional properties of TEC-treated cartilage-like repaired tissues are recovered to normal level in mature animals, while they are unrecovered to normal level due to underdeveloped, permeable surface layer in immature animals.

  • EMBC - Frictional properties of articular cartilage-like tissues repaired with a mesenchymal stem cell-based tissue Engineered Construct
    Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and, 2013
    Co-Authors: Hiromichi Fujie, Norimasa Nakamura
    Abstract:

    We have been developing a novel tissue engineering technique for cartilage repair using a scaffold-free tissue Engineered Construct (TEC) bio-synthesized from synovium-derived mesenchymal stem cells (MSCs). In the present study, the effect of TEC on the repair of chondral defect in the femoral condyle of immature and mature pigs were investigated. The permeability of TEC-treated repaired tissues was significantly higher than normal level at surface layer in immature animals, while the permeability was slightly higher than normal level at middle and deep layers in mature animals. In immature animals, the coefficient of friction of TEC-treated tissues against a glass plate was load-dependently increased, with a significantly higher value than normal level observed at a high load (280 kPa). In contrast, the coefficient of friction was load-dependently decreased in mature animals, with no significant differences from normal level observed at all loads (70, 140, and 280 kPa). It is suggested that the frictional properties of TEC-treated cartilage-like repaired tissues are recovered to normal level in mature animals, while they are unrecovered to normal level due to underdeveloped, permeable surface layer in immature animals.

Wataru Ando - One of the best experts on this subject based on the ideXlab platform.

  • first in human pilot study of implantation of a scaffold free tissue Engineered Construct generated from autologous synovial mesenchymal stem cells for repair of knee chondral lesions
    American Journal of Sports Medicine, 2018
    Co-Authors: Kazunori Shimomura, David A. Hart, Ryota Chijimatsu, Wataru Ando, Yukihiko Yasui, Kota Koizumi, Yasukazu Yonetani, Takashi Nishii, Takashi Kanamoto, Shuji Horibe
    Abstract:

    Background:Articular cartilage has limited healing capacity, owing in part to poor vascularity and innervation. Once injured, it cannot be repaired, typically leading to high risk for developing osteoarthritis. Thus, cell-based and/or tissue-Engineered approaches have been investigated; however, no approach has yet achieved safety and regenerative repair capacity via a simple implantation procedure.Purpose:To assess the safety and efficacy of using a scaffold-free tissue-Engineered Construct (TEC) derived from autologous synovial membrane mesenchymal stem cells (MSCs) for effective cartilage repair.Study Design:Case series; Level of evidence, 4.Methods:Five patients with symptomatic knee chondral lesions (1.5-3.0 cm2) on the medial femoral condyle, lateral femoral condyle, or femoral groove were included. Synovial MSCs were isolated from arthroscopic biopsy specimens and cultured to develop a TEC that matched the lesion size. The TECs were then implanted into chondral defects without fixation and assessed...

  • comparison of 2 different formulations of artificial bone for a hybrid implant with a tissue Engineered Construct derived from synovial mesenchymal stem cells a study using a rabbit osteochondral defect model
    American Journal of Sports Medicine, 2017
    Co-Authors: Kazunori Shimomura, David A. Hart, Hiromichi Fujie, Wataru Ando, Ryosuke Nansai, Shuji Horibe, Yu Moriguchi, Alberto Gobbi, Hideki Yoshikawa
    Abstract:

    Background:Previously, we developed a hybrid implant composed of hydroxyapatite (HA)–based artificial bone coupled with a mesenchymal stem cell (MSC)–based scaffold-free tissue-Engineered Construct (TEC) and demonstrated its feasibility for osteochondral repair. Beta-tricalcium phosphate (βTCP) may be a promising alternative to HA, as it is a highly biocompatible material and is resorbed more rapidly than HA in vivo.Hypothesis:A βTCP-based hybrid TEC implant will exhibit superior osteochondral repair when directly compared with an HA-based hybrid implant, as tested using a rabbit osteochondral defect model.Study Design:Controlled laboratory study.Methods:Osteochondral defects were created in the femoral groove of skeletally mature rabbits. The TEC and artificial bone, using either HA or βTCP with the same porosities and similar mechanical properties, were hybridized and then implanted in the defects. A histological evaluation and microindentation testing were performed for the assessment of repair tissue....

  • zone specific integrated cartilage repair using a scaffold free tissue Engineered Construct derived from allogenic synovial mesenchymal stem cells biomechanical and histological assessments
    Journal of Biomechanics, 2015
    Co-Authors: Kazunori Shimomura, Norimasa Nakamura, David A. Hart, Hiromichi Fujie, Wataru Ando, Ryosuke Nansai, Yu Moriguchi
    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 12.8 MPa 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.

  • repair of meniscal lesions using a scaffold free tissue Engineered Construct derived from allogenic synovial mscs in a miniature swine model
    Biomaterials, 2013
    Co-Authors: Yu Moriguchi, Kazunori Shimomura, David A. Hart, Kosuke Tateishi, Wataru Ando, Yoshinari Tanaka, Yasukazu Yonetani, Alberto Gobbi, Keisuke Kita, Konsei Shino
    Abstract:

    Abstract The menisci of the knee are fibro-cartilaginous tissues and play important roles in the joint, and the loss of the meniscus predisposes the knee to degenerative changes. However, the menisci have limited healing potential due to the paucity of vascularity. The purpose of the present study was to test the feasibility of a scaffold-free tissue-Engineered Construct (TEC) derived from synovial mesenchymal stem cells (MSCs) to repair incurable meniscal lesions. Porcine synovial MSCs were cultured in monolayers at high density in the presence of ascorbic acid followed by the suspension culture to develop a three-dimensional cell/matrix Construct (TEC). A 4-mm cylindrical defect was created bilaterally in the medial meniscus of skeletally mature miniature pigs. The defects were implanted with an allogenic TEC or were left empty. After 6 months, the TEC-treated defects were consistently repaired by a fibro-cartilaginous tissue with good tissue integration to the adjacent host meniscal tissue, while the untreated were either partially or not repaired. The ratio of Safranin O positive area within the central body of the meniscus adjacent to the original defect was significantly higher in the TEC-treated group than in the control group. Moreover, TEC treatment significantly reduced the size and severity of post-traumatic chondral lesions on the tibial plateau. These results suggest that the TEC could be a promising stem cell-based implant to repair meniscal lesions with preventive effects from meniscal body degeneration and the development of post-traumatic arthritis.

  • detection of abnormalities in the superficial zone of cartilage repaired using a tissue Engineered Construct derived from synovial stem cells
    European Cells & Materials, 2012
    Co-Authors: Wataru Ando, Kazunori Shimomura, David A. Hart, Hiromichi Fujie, Hideki Yoshikawa, Ryosuke Nansai, Yu Moriguchi, Norimasa Nakamura
    Abstract:

    The present study investigated the surface structure and mechanical properties of repair cartilage generated from a tissue Engineered Construct (TEC) derived from synovial mesenchymal stem cells at six months post-implantation compared to those of uninjured cartilage. TEC-mediated repair tissue was cartilaginous with Safranin O staining, and had comparable macro-scale compressive properties with uninjured cartilage. However, morphological assessments revealed that the superficial zone of TEC-mediated tissue was more fibrocartilage-like, in contrast to the middle or deep zones that were more hyaline cartilage-like with Safranin O staining. Histological scoring of the TECmediated tissue was significantly lower in the superficial zone than in the middle and deep zones. Scanning electron microscopy showed a thick tangential bundle of collagen fibres at the most superficial layer of uninjured cartilage, while no corresponding structure was detected at the surface of TEC-mediated tissue. Immunohistochemical analysis revealed that PRG4 was localised in the superficial area of uninjured cartilage, as well as the TEC-mediated tissue. Friction testing showed that the lubrication properties of the two tissues was similar, however, microindentation analysis revealed that the surface stiffness of the TEC-repair tissue was significantly lower than that of uninjured cartilage. Permeability testing indicated that the TEC-mediated tissue exhibited lower water retaining capacity than did uninjured cartilage, specifically at the superficial zone. Thus, TEC-mediated tissue exhibited compromised mechanical properties at the superficial zone, properties which need improvement in the future for maintenance of long term repair cartilage integrity.

Hideki Yoshikawa - One of the best experts on this subject based on the ideXlab platform.

  • enhanced repair of meniscal hoop structure injuries using an aligned electrospun nanofibrous scaffold combined with a mesenchymal stem cell derived tissue Engineered Construct
    Biomaterials, 2019
    Co-Authors: Kazunori Shimomura, Norimasa Nakamura, David A. Hart, Hideki Yoshikawa, Benjamin B Rothrauff, Shuichi Hamamoto, Masato Kobayashi, Rocky S Tuan
    Abstract:

    Abstract Damage to the meniscal hoop structure results in loss of biomechanical function, which potentially leads to the extrusion of the meniscus from the weight bearing area. However, there have been no established, effective treatments for such injuries. The purpose of this study was to investigate the applicability of cell-seeded nanofibrous scaffolds to repair the damaged meniscal hoop structure along with the prevention of subsequent cartilage degeneration using a rabbit model. Meniscal radial defects (5 mm width) in the medial meniscus were treated by wrapping and suturing with either an aligned electrospun nanofibrous scaffold alone or a scaffold combined with a tissue Engineered Construct (TEC) derived from synovial mesenchymal stem cells (MSCs), with the scaffold fiber direction matching that of the meniscal circumferential fibers. The MSC-based TEC-combined nanofibrous scaffolds contributed significantly to the prevention of meniscal extrusion and exerted a chondroprotective effect, compared with either scaffold alone or the untreated control groups. Also, meniscal defects treated with such TEC-combined nanofibrous scaffolds were consistently repaired with a fibrocartilaginous tissue. In this study, we have demonstrated the feasibility of a combined TEC-nanofibrous scaffold to repair the meniscal hoop structure, and prevent the progression to cartilage degeneration, as a potential tissue engineering method.

  • comparison of 2 different formulations of artificial bone for a hybrid implant with a tissue Engineered Construct derived from synovial mesenchymal stem cells a study using a rabbit osteochondral defect model
    American Journal of Sports Medicine, 2017
    Co-Authors: Kazunori Shimomura, David A. Hart, Hiromichi Fujie, Wataru Ando, Ryosuke Nansai, Shuji Horibe, Yu Moriguchi, Alberto Gobbi, Hideki Yoshikawa
    Abstract:

    Background:Previously, we developed a hybrid implant composed of hydroxyapatite (HA)–based artificial bone coupled with a mesenchymal stem cell (MSC)–based scaffold-free tissue-Engineered Construct (TEC) and demonstrated its feasibility for osteochondral repair. Beta-tricalcium phosphate (βTCP) may be a promising alternative to HA, as it is a highly biocompatible material and is resorbed more rapidly than HA in vivo.Hypothesis:A βTCP-based hybrid TEC implant will exhibit superior osteochondral repair when directly compared with an HA-based hybrid implant, as tested using a rabbit osteochondral defect model.Study Design:Controlled laboratory study.Methods:Osteochondral defects were created in the femoral groove of skeletally mature rabbits. The TEC and artificial bone, using either HA or βTCP with the same porosities and similar mechanical properties, were hybridized and then implanted in the defects. A histological evaluation and microindentation testing were performed for the assessment of repair tissue....

  • Osteochondral Repair Using a Hybrid Implant Composed of Stem Cells and Biomaterial
    Bio-orthopaedics, 2017
    Co-Authors: Kazunori Shimomura, David A. Hart, Hiromichi Fujie, Hideki Yoshikawa, Norimasa Nakamura
    Abstract:

    Osteoarthritis (OA) is a common disease, which could potentially affect the quality of life of both young and elderly populations worldwide. The management of OA remains challenging and controversial. Although there are several clinical options for the treatment of OA, it has proven difficult to restore the damaged articular cartilage due to the limited healing capacity. With the advancements in tissue engineering approaches including cell-based technologies and development of biomaterial scaffolds over the past decade, new therapeutic options for patients with osteochondral lesions may be potentially available. This chapter will highlight the current techniques and recent advances of tissue-Engineered biomaterial scaffolds, which can mimic the native osteochondral complex, for osteochondral tissue regeneration. Moreover, we will introduce our novel technique using a hybrid implant composed of artificial bone coupled with a mesenchymal stem cell (MSC)–based scaffold-free tissue-Engineered Construct (TEC) and show its feasibility for osteochondral repair.

  • detection of abnormalities in the superficial zone of cartilage repaired using a tissue Engineered Construct derived from synovial stem cells
    European Cells & Materials, 2012
    Co-Authors: Wataru Ando, Kazunori Shimomura, David A. Hart, Hiromichi Fujie, Hideki Yoshikawa, Ryosuke Nansai, Yu Moriguchi, Norimasa Nakamura
    Abstract:

    The present study investigated the surface structure and mechanical properties of repair cartilage generated from a tissue Engineered Construct (TEC) derived from synovial mesenchymal stem cells at six months post-implantation compared to those of uninjured cartilage. TEC-mediated repair tissue was cartilaginous with Safranin O staining, and had comparable macro-scale compressive properties with uninjured cartilage. However, morphological assessments revealed that the superficial zone of TEC-mediated tissue was more fibrocartilage-like, in contrast to the middle or deep zones that were more hyaline cartilage-like with Safranin O staining. Histological scoring of the TECmediated tissue was significantly lower in the superficial zone than in the middle and deep zones. Scanning electron microscopy showed a thick tangential bundle of collagen fibres at the most superficial layer of uninjured cartilage, while no corresponding structure was detected at the surface of TEC-mediated tissue. Immunohistochemical analysis revealed that PRG4 was localised in the superficial area of uninjured cartilage, as well as the TEC-mediated tissue. Friction testing showed that the lubrication properties of the two tissues was similar, however, microindentation analysis revealed that the surface stiffness of the TEC-repair tissue was significantly lower than that of uninjured cartilage. Permeability testing indicated that the TEC-mediated tissue exhibited lower water retaining capacity than did uninjured cartilage, specifically at the superficial zone. Thus, TEC-mediated tissue exhibited compromised mechanical properties at the superficial zone, properties which need improvement in the future for maintenance of long term repair cartilage integrity.

  • treatment of partial growth arrest using an in vitro generated scaffold free tissue Engineered Construct derived from rabbit synovial mesenchymal stem cells
    Journal of Pediatric Orthopaedics, 2012
    Co-Authors: Kiyoshi Yoshida, Norimasa Nakamura, Chikahisa Higuchi, Akio Nakura, Hideki Yoshikawa
    Abstract:

    BACKGROUND: Injuries to the epiphyseal plate sometimes result in partial growth arrest, which can lead to the development of angular deformities and limb length discrepancies in growing children. The aim of this study was to develop a new treatment for partial growth arrest of the physis. For this purpose, we investigated the feasibility of an in vitro-generated scaffold-free tissue-Engineered Construct (TEC) derived from synovial mesenchymal stem cells (MSCs) in a rabbit growth arrest model. METHODS: An experimental model for growth arrest was created by excising the medial half of the proximal growth plate of tibias from 6-week-old New Zealand White rabbits. Three experimental groups were set to evaluate TEC implantation: group 1, no implantation as controls; group 2, implantation of bone wax as additional controls; and group 3, implantation of TEC in the lesion. RESULTS: In group 1, all damaged growth plates were arrested and angular deformities appeared 4 weeks later. In groups 2 and 3, angular deformities were less than in the control group. Histologic images showed bone bridges developed at the damaged growth plate in group 1. Regeneration of growth plates was recognized in groups 2 and 3. Histologic examination showed greater regeneration of the growth plate in group 3 than in group 2. In addition, MSCs in the TEC differentiated into proliferative and prehypertrophic chondrocyte-like cells. CONCLUSIONS: A scaffold-free 3D TEC made using cultured synovium-derived MSCs differentiated into proliferative and prehypertrophic chondrocyte-like cells. CLINICAL RELEVANCE: The results of this experimental study suggest that scaffold-free 3D TEC made using cultured synovium-derived MSCs can be a new approach for the repair of epiphyseal injury. Clinical effectiveness of a scaffold-free 3D TEC for growth arrest remains to be determined.

David A. Hart - One of the best experts on this subject based on the ideXlab platform.

  • enhanced repair of meniscal hoop structure injuries using an aligned electrospun nanofibrous scaffold combined with a mesenchymal stem cell derived tissue Engineered Construct
    Biomaterials, 2019
    Co-Authors: Kazunori Shimomura, Norimasa Nakamura, David A. Hart, Hideki Yoshikawa, Benjamin B Rothrauff, Shuichi Hamamoto, Masato Kobayashi, Rocky S Tuan
    Abstract:

    Abstract Damage to the meniscal hoop structure results in loss of biomechanical function, which potentially leads to the extrusion of the meniscus from the weight bearing area. However, there have been no established, effective treatments for such injuries. The purpose of this study was to investigate the applicability of cell-seeded nanofibrous scaffolds to repair the damaged meniscal hoop structure along with the prevention of subsequent cartilage degeneration using a rabbit model. Meniscal radial defects (5 mm width) in the medial meniscus were treated by wrapping and suturing with either an aligned electrospun nanofibrous scaffold alone or a scaffold combined with a tissue Engineered Construct (TEC) derived from synovial mesenchymal stem cells (MSCs), with the scaffold fiber direction matching that of the meniscal circumferential fibers. The MSC-based TEC-combined nanofibrous scaffolds contributed significantly to the prevention of meniscal extrusion and exerted a chondroprotective effect, compared with either scaffold alone or the untreated control groups. Also, meniscal defects treated with such TEC-combined nanofibrous scaffolds were consistently repaired with a fibrocartilaginous tissue. In this study, we have demonstrated the feasibility of a combined TEC-nanofibrous scaffold to repair the meniscal hoop structure, and prevent the progression to cartilage degeneration, as a potential tissue engineering method.

  • first in human pilot study of implantation of a scaffold free tissue Engineered Construct generated from autologous synovial mesenchymal stem cells for repair of knee chondral lesions
    American Journal of Sports Medicine, 2018
    Co-Authors: Kazunori Shimomura, David A. Hart, Ryota Chijimatsu, Wataru Ando, Yukihiko Yasui, Kota Koizumi, Yasukazu Yonetani, Takashi Nishii, Takashi Kanamoto, Shuji Horibe
    Abstract:

    Background:Articular cartilage has limited healing capacity, owing in part to poor vascularity and innervation. Once injured, it cannot be repaired, typically leading to high risk for developing osteoarthritis. Thus, cell-based and/or tissue-Engineered approaches have been investigated; however, no approach has yet achieved safety and regenerative repair capacity via a simple implantation procedure.Purpose:To assess the safety and efficacy of using a scaffold-free tissue-Engineered Construct (TEC) derived from autologous synovial membrane mesenchymal stem cells (MSCs) for effective cartilage repair.Study Design:Case series; Level of evidence, 4.Methods:Five patients with symptomatic knee chondral lesions (1.5-3.0 cm2) on the medial femoral condyle, lateral femoral condyle, or femoral groove were included. Synovial MSCs were isolated from arthroscopic biopsy specimens and cultured to develop a TEC that matched the lesion size. The TECs were then implanted into chondral defects without fixation and assessed...

  • comparison of 2 different formulations of artificial bone for a hybrid implant with a tissue Engineered Construct derived from synovial mesenchymal stem cells a study using a rabbit osteochondral defect model
    American Journal of Sports Medicine, 2017
    Co-Authors: Kazunori Shimomura, David A. Hart, Hiromichi Fujie, Wataru Ando, Ryosuke Nansai, Shuji Horibe, Yu Moriguchi, Alberto Gobbi, Hideki Yoshikawa
    Abstract:

    Background:Previously, we developed a hybrid implant composed of hydroxyapatite (HA)–based artificial bone coupled with a mesenchymal stem cell (MSC)–based scaffold-free tissue-Engineered Construct (TEC) and demonstrated its feasibility for osteochondral repair. Beta-tricalcium phosphate (βTCP) may be a promising alternative to HA, as it is a highly biocompatible material and is resorbed more rapidly than HA in vivo.Hypothesis:A βTCP-based hybrid TEC implant will exhibit superior osteochondral repair when directly compared with an HA-based hybrid implant, as tested using a rabbit osteochondral defect model.Study Design:Controlled laboratory study.Methods:Osteochondral defects were created in the femoral groove of skeletally mature rabbits. The TEC and artificial bone, using either HA or βTCP with the same porosities and similar mechanical properties, were hybridized and then implanted in the defects. A histological evaluation and microindentation testing were performed for the assessment of repair tissue....

  • Osteochondral Repair Using a Hybrid Implant Composed of Stem Cells and Biomaterial
    Bio-orthopaedics, 2017
    Co-Authors: Kazunori Shimomura, David A. Hart, Hiromichi Fujie, Hideki Yoshikawa, Norimasa Nakamura
    Abstract:

    Osteoarthritis (OA) is a common disease, which could potentially affect the quality of life of both young and elderly populations worldwide. The management of OA remains challenging and controversial. Although there are several clinical options for the treatment of OA, it has proven difficult to restore the damaged articular cartilage due to the limited healing capacity. With the advancements in tissue engineering approaches including cell-based technologies and development of biomaterial scaffolds over the past decade, new therapeutic options for patients with osteochondral lesions may be potentially available. This chapter will highlight the current techniques and recent advances of tissue-Engineered biomaterial scaffolds, which can mimic the native osteochondral complex, for osteochondral tissue regeneration. Moreover, we will introduce our novel technique using a hybrid implant composed of artificial bone coupled with a mesenchymal stem cell (MSC)–based scaffold-free tissue-Engineered Construct (TEC) and show its feasibility for osteochondral repair.

  • zone specific integrated cartilage repair using a scaffold free tissue Engineered Construct derived from allogenic synovial mesenchymal stem cells biomechanical and histological assessments
    Journal of Biomechanics, 2015
    Co-Authors: Kazunori Shimomura, Norimasa Nakamura, David A. Hart, Hiromichi Fujie, Wataru Ando, Ryosuke Nansai, Yu Moriguchi
    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 12.8 MPa 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.