title: Paracrine effect of transplanted rib chondrocyte spheroids supports formation of secondary cartilage repair tissue.
abstract: The study's objective was to investigate if transplanted chondrocyte or periosteal cell spheroids have influence on ingrowing bone marrow-derived cells in a novel cartilage repair approach in miniature pigs. Autologous rib chondrocytes or periosteal cells were cultured as spheroids and press-fitted into cavities that were milled into large, superficial chondral lesions of the patellar joint surface. Within the milled cavities, the subchondral bone plate was either penetrated or left intact (full-thickness or partial-thickness cavities). The transplantation of chondrocyte spheroids into full-thickness cavities induced the formation of additional secondary repair cartilage that exceeded the original volume of the transplanted spheroids. The resulting continuous tissue was rich in proteoglycans and stained positive for type II collagen. Cell labeling revealed that secondarily invading repair cells did not originate from transplanted spheroids, but rather from arroded bone marrow. However, secondary invasion of repair cells was less pronounced following transplantation of periosteal cells and absent in partial-thickness cavities. According to in vitro analyses, these observations could be ascribed to the ability of chondrocyte spheroids to secrete relevant amounts of bone morphogenetic protein-2, which was not detected for periosteal cells. Transplanted chondrocyte spheroids exert a dual function: they provide cells for the repair tissue and have a stimulatory paracrine activity, which promotes ingrowth and chondrogenesis of bone marrow-derived cells.
authors.affiliation: Department of Orthopaedic Trauma Surgery, University Hospital Erlangen, Erlangen, Germany. kolja.gelse@web.de
authors.forename: Kolja
authors.initials: K
authors.lastname: Gelse
authors.forename: Matthias
authors.initials: M
authors.lastname: Brem
authors.forename: Patricia
authors.initials: P
authors.lastname: Klinger
authors.forename: Andreas
authors.initials: A
authors.lastname: Hess
authors.forename: Bernd
authors.initials: B
authors.lastname: Swoboda
authors.forename: Friedrich
authors.initials: F
authors.lastname: Hennig
authors.forename: Alexander
authors.initials: A
authors.lastname: Olk
mesh_terms: D000818:Animals; D001854:Bone Marrow Cells / Q000166:cytology / Q000378:metabolism; D055396:Bone Morphogenetic Protein 2 / Q000378:metabolism; D002356:Cartilage / Q000166:cytology / Q000293:injuries* / Q000378:metabolism; D002478:Cells, Cultured; D019902:Chondrocytes / Q000166:cytology / Q000378:metabolism* / Q000637:transplantation*; D020219:Chondrogenesis / Q000502:physiology*; D024043:Collagen Type II / Q000378:metabolism; D005260:Female; D006801:Humans; D019899:Paracrine Communication / Q000502:physiology*; D011509:Proteoglycans / Q000378:metabolism; D012272:Ribs / Q000166:cytology*; D018874:Spheroids, Cellular / Q000166:cytology / Q000378:metabolism / Q000637:transplantation; D013234:Stem Cells / Q000166:cytology / Q000378:metabolism; D013552:Swine; D013556:Swine, Miniature; D014945:Wound Healing / Q000502:physiology
chemical_list: D055396:Bone Morphogenetic Protein 2; D024043:Collagen Type II; D011509:Proteoglycans