title: Immunohistochemical study of collagen types I and II and procollagen IIA in human cartilage repair tissue following autologous chondrocyte implantation.
abstract: This study has assessed the relative proportions of type I and II collagens and IIA procollagen in full depth biopsies of repair tissue in a large sample of patients treated with autologous chondrocyte implantation (ACI). Sixty five full depth biopsies were obtained from knees of 58 patients 8-60 months after treatment by ACI alone (n=55) or in combination with mosaicplasty (n=10). In addition articular cartilage was examined from eight individuals (aged 10-50) as controls. Morphology and semi-quantitative immunohistochemistry for collagen types I and II and procollagen IIA in the repair tissue were studied. Repair cartilage thickness was 2.89+/-1.5 mm and there was good basal integration between the repair cartilage, calcified cartilage and subchondral bone. Sixty five percent of the biopsies were predominantly fibrocartilage (mostly type I collagen and IIA procollagen), 15% were hyaline cartilage (mostly type II collagen), 17% were of mixed morphology and 3% were fibrous tissue (mostly type I collagen). Type II collagen and IIA procollagen were usually found in the lower regions near the bone and most type II collagen was present 30-60 months after treatment. The presence of type IIA procollagen in the repair tissue supports our hypothesis that this is indicative of a developing cartilage, with the ratio of type II collagen:procollagen IIA increasing from <2% in the first two years post-treatment to 30% three to five years after treatment. This suggests that cartilage repair tissue produced following ACI treatment, is likely to take some years to mature.
authors.affiliation: Centre for Spinal Studies, Robert Jones & Agnes Hunt Orthopaedic Hospital, Oswestry, Shropshire, UK. Sally.Roberts@rjah.nhs.uk
authors.forename: S
authors.initials: S
authors.lastname: Roberts
authors.forename: J
authors.initials: J
authors.lastname: Menage
authors.forename: L J
authors.initials: LJ
authors.lastname: Sandell
authors.forename: E H
authors.initials: EH
authors.lastname: Evans
authors.forename: J B
authors.initials: JB
authors.lastname: Richardson
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000378:metabolism; D001706:Biopsy; D002358:Cartilage, Articular / Q000378:metabolism / Q000473:pathology / Q000601:surgery*; D017690:Cell Transplantation; D019902:Chondrocytes / Q000378:metabolism / Q000637:transplantation*; D024042:Collagen Type I / Q000378:metabolism*; D024043:Collagen Type II / Q000378:metabolism*; D051445:Fibrocartilage / Q000378:metabolism* / Q000473:pathology; D019085:Fluorescent Antibody Technique, Direct; D006801:Humans; D007124:Immunoenzyme Techniques / Q000379:methods*
chemical_list: D015415:Biomarkers; D024042:Collagen Type I; D024043:Collagen Type II