title: A novel, cryopreserved, viable osteochondral allograft designed to augment marrow stimulation for articular cartilage repair.
abstract: BACKGROUND
  Here, we describe the design and characterization of a novel, cryopreserved, viable osteochondral allograft (CVOCA), along with evidence that the CVOCA can improve outcomes of marrow stimulation for articular cartilage repair.
  
  
  METHODS
  Histological staining was performed to evaluate the CVOCA tissue architecture. CVOCAs were tested for the presence of extracellular matrix (ECM) proteins and chondrogenic growth factors using ELISA. Cell viability and composition were examined via live/dead staining, fluorescence-activated cell sorting (FACS) analysis, and immunofluorescence staining. FACS analysis and a TNF-α secretion bioassay were used to confirm the lack of immunogenic cells. Effects of the CVOCA on mesenchymal stem cells (MSCs) were tested using in vitro migration and chondrogenesis assays. The ability of the CVOCA to augment marrow stimulation in vivo was evaluated in a goat model.
  
  
  RESULTS
  A method of tissue processing and preservation was developed resulting in a CVOCA with pores and minimal bone. The pores were found to increase the flexibility of the CVOCA and enhance growth factor release. Histological staining revealed that all three zones of hyaline cartilage were preserved within the CVOCA. Chondrogenic growth factors (TGF-β1, TGF-β3, BMP-2, BMP-4, BMP-7, bFGF, IGF-1) and ECM proteins (type II collagen, hyaluronan) were retained within the CVOCA, and their sustained release in culture was observed (TGF β1, TGF-β2, aggrecan). The cells within the CVOCA were confirmed to be chondrocytes and remained viable and functional post-thaw. Immunogenicity testing confirmed the absence of immunogenic cells. The CVOCA induced MSC migration and chondrogenesis in vitro. Experimental results using devitalized flash frozen osteochondral allografts revealed the importance of preserving all components of articular cartilage in the CVOCA. Goats treated with the CVOCA and marrow stimulation exhibited better repair compared to goats treated with marrow stimulation alone.
  
  
  CONCLUSIONS
  The CVOCA retains viable chondrocytes, chondrogenic growth factors, and ECM proteins within the intact architecture of native hyaline cartilage. The CVOCA promotes MSC migration and chondrogenesis following marrow stimulation, improving articular cartilage repair.
authors.affiliation: Osiris Therapeutics, Inc., Albert Einstein Drive, Columbia, MD, USA. sgeraghty@osiris.com.
authors.forename: Sandra
authors.initials: S
authors.lastname: Geraghty
authors.affiliation: Osiris Therapeutics, Inc., Albert Einstein Drive, Columbia, MD, USA. jkuang@osiris.com.
authors.forename: Jin-Qiang
authors.initials: JQ
authors.lastname: Kuang
authors.affiliation: Osiris Therapeutics, Inc., Albert Einstein Drive, Columbia, MD, USA. dyoo002@yahoo.com.|Tissue Banks International, Park Avenue, Baltimore, MD, USA. dyoo002@yahoo.com.
authors.forename: Dana
authors.initials: D
authors.lastname: Yoo
authors.affiliation: Osiris Therapeutics, Inc., Albert Einstein Drive, Columbia, MD, USA. mwilliams@tbionline.org.|Tissue Banks International, Park Avenue, Baltimore, MD, USA. mwilliams@tbionline.org.
authors.forename: Michelle
authors.initials: M
authors.lastname: LeRoux-Williams
authors.affiliation: Department of Orthopaedics, Keck School of Medicine, University of Southern California, San Pablo Street, Los Angeles, CA, USA. Thomas.Vangsness@med.usc.edu.
authors.forename: C Thomas
authors.initials: CT
authors.lastname: Vangsness
authors.affiliation: Osiris Therapeutics, Inc., Albert Einstein Drive, Columbia, MD, USA. adanilkovitch@osiris.com.
authors.forename: Alla
authors.initials: A
authors.lastname: Danilkovitch
mesh_terms: D000293:Adolescent; D000328:Adult; D064591:Allografts / Q000737:chemistry / Q000637:transplantation*; D000818:Animals; D002358:Cartilage, Articular / Q000166:cytology / Q000293:injuries / Q000601:surgery*; D020219:Chondrogenesis / Q000502:physiology; D015925:Cryopreservation; D004797:Enzyme-Linked Immunosorbent Assay; D005109:Extracellular Matrix / Q000378:metabolism; D006041:Goats; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000032:analysis; D059630:Mesenchymal Stem Cells / Q000378:metabolism; D055815:Young Adult
chemical_list: D036341:Intercellular Signaling Peptides and Proteins