title: Ankle bipolar fresh osteochondral allograft survivorship and integration: transplanted tissue genetic typing and phenotypic characteristics.
abstract: BACKGROUND
  Fresh osteochondral allografts represent a treatment option for early ankle posttraumatic arthritis. Transplanted cartilage survivorship, integration, and colonization by recipient cells have not been fully investigated. The aim of this study was to evaluate the ability of recipient cells to colonize the allograft cartilage and to assess allograft cell phenotype.
  
  
  METHODS
  Seventeen ankle allograft samples were studied. Retrieved allograft cartilage DNA from fifteen cases was compared with recipient and donor constitutional DNA by genotyping. In addition, gene expression was evaluated on six allograft cartilage samples by means of real-time reverse transcription-polymerase chain reaction. Histology and immunohistochemistry were performed to support molecular observations.
  
  
  RESULTS
  Of fifteen genotyped allografts, ten completely matched to the host, three matched to the donor, and two showed a mixed profile. Gene expression analysis showed that grafted cartilage expressed cartilage-specific markers.
  
  
  CONCLUSIONS
  The rare persistence of donor cells and the prevailing presence of host DNA in retrieved ankle allografts suggest the ingrowth of recipient cells into the allograft cartilage, presumably migrating from the subchondral bone, in accordance with morphological findings. The expression of chondrogenic markers in some of the samples argues for the acquisition of a chondrocyte-like phenotype by these cells.
  
  
  CONCLUSIONS
  To our knowledge, this is the first report describing the colonization of ankle allograft cartilage by host cells showing the acquisition of a chondrocyte-like phenotype.
authors.affiliation: SC Laboratorio di Immunoreumatologia e Rigenerazione Tissutale/Laboratorio RAMSES (S.N., G.D., B.G., A.F.), SC Clinica Ortopedica Traumatologica I (F.V., A.R., R.B., S.G.), Istituto Ortopedico Rizzoli, Via di Barbiano 1/10, 40136 Bologna, Italy. E-mail address for S. Neri: simona.neri@ior.it. E-mail address for F. Vannini: francesca.vannini@ior.it. E-mail address for G. Desando: giovanna.desando@ior.it. E-mail address for B. Grigolo: brunella.grigolo@ior.it. E-mail address for A. Ruffilli: aruffilli@tiscali.it. E-mail address for R. Buda: roberto.buda@ior.it. E-mail address for A. Facchini: andrea.facchini@unibo.it. E-mail address for S. Giannini: sandro.giannini@ior.it.
authors.forename: Simona
authors.initials: S
authors.lastname: Neri
authors.forename: Francesca
authors.initials: F
authors.lastname: Vannini
authors.forename: Giovanna
authors.initials: G
authors.lastname: Desando
authors.forename: Brunella
authors.initials: B
authors.lastname: Grigolo
authors.forename: Alberto
authors.initials: A
authors.lastname: Ruffilli
authors.forename: Roberto
authors.initials: R
authors.lastname: Buda
authors.forename: Andrea
authors.initials: A
authors.lastname: Facchini
authors.forename: Sandro
authors.initials: S
authors.lastname: Giannini
mesh_terms: D000293:Adolescent; D000328:Adult; D064591:Allografts / Q000502:physiology*; D016512:Ankle Injuries / Q000150:complications*; D001168:Arthritis / Q000209:etiology / Q000235:genetics / Q000601:surgery*; D015415:Biomarkers / Q000378:metabolism; D016025:Bone Transplantation; D016000:Cluster Analysis; D005260:Female; D005500:Follow-Up Studies; D020869:Gene Expression Profiling; D005819:Genetic Markers; D005838:Genotype; D006085:Graft Survival / Q000235:genetics* / Q000502:physiology; D006801:Humans; D051457:Hyaline Cartilage / Q000502:physiology / Q000637:transplantation*; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D010641:Phenotype; D060888:Real-Time Polymerase Chain Reaction; D012038:Regeneration / Q000235:genetics* / Q000502:physiology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D015415:Biomarkers; D005819:Genetic Markers