title: Alterations in the chondroitin sulfate chain in human osteoarthritic cartilage of the knee.
abstract: OBJECTIVE
  To determine whether the structure of chondroitin sulfate (CS) in cartilage is reflected by the degree of cartilage degeneration in patients with osteoarthritis (OA) of the knee and to determine how CS biosynthesis affects cartilage degeneration.
  
  
  METHODS
  Two osteoarthritic cartilage samples were obtained from medial femoral condyle (MFC) and lateral femoral condyle (LFC) of 24 knees with end-stage OA. The samples were assigned to two groups as follows: lesion and remote cartilage were adjacent to and remote from the osteoarthritic cartilage, respectively. Histological grade was determined according to the Mankin score. The CS concentration and chain length were determined using high-performance liquid chromatography (HPLC) and gel filtration chromatography, respectively. Expression of the gene encoding CS glycosyltransferase was evaluated using a real-time quantitative polymerase chain reaction (qPCR) assay. These results were compared between lesion and remote cartilage.
  
  
  RESULTS
  The Mankin score indicated that lesion cartilage was more degraded compared with remote cartilage. Although the CS levels varied among individuals, the mean CS concentration and chain length were significantly lower and shorter in lesion cartilage than in remote cartilage, respectively (concentration: 12.04 vs 14.84 μg/mg wet weight, P = 0.021; chain length: 5.36 vs 6.19 kDa, P = 0.026). Three genes encoding CS glycosyltransferases (CHPF, CSGALNACT1, CSGALNACT2) were expressed at lower levels in lesion cartilage.
  
  
  CONCLUSIONS
  In the osteoarthritic knee, the CS concentration and chain length were reduced closer to the more degraded cartilage with decreasing CS glycosyltransferase gene expression. Inhibition of CS glycosyltransferase gene expression may reduce CS chain length, which may contribute to OA progression.
authors.affiliation: Department of Orthopaedic Surgery, Gifu University, Graduate School of Medicine, Gifu, Japan. Electronic address: ishidaiishidai@kha.biglobe.ne.jp.
authors.forename: D
authors.initials: D
authors.lastname: Ishimaru
authors.affiliation: Institute for Molecular Science of Medicine, Aichi Medical University, Nagakute, Aichi, Japan. Electronic address: nsugiura@aichi-med-u.ac.jp.
authors.forename: N
authors.initials: N
authors.lastname: Sugiura
authors.affiliation: Department of Orthopaedic Surgery, Gifu University, Graduate School of Medicine, Gifu, Japan. Electronic address: hakiyama@gifu-u.ac.jp.
authors.forename: H
authors.initials: H
authors.lastname: Akiyama
authors.affiliation: Institute for Molecular Science of Medicine, Aichi Medical University, Nagakute, Aichi, Japan. Electronic address: wannabee@aichi-med-u.ac.jp.
authors.forename: H
authors.initials: H
authors.lastname: Watanabe
authors.affiliation: Department of Orthopaedic Surgery, Gifu University, Graduate School of Medicine, Gifu, Japan. Electronic address: mkazuu@gifu-u.ac.jp.
authors.forename: K
authors.initials: K
authors.lastname: Matsumoto
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000378:metabolism; D002358:Cartilage, Articular / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000473:pathology; D019902:Chondrocytes / Q000378:metabolism*; D002809:Chondroitin Sulfates / Q000737:chemistry / Q000378:metabolism*; D005260:Female; D015971:Gene Expression Regulation, Enzymologic; D016695:Glycosyltransferases / Q000096:biosynthesis / Q000235:genetics; D006801:Humans; D016916:Joint Deformities, Acquired / Q000000981:diagnostic imaging / Q000209:etiology / Q000378:metabolism; D007719:Knee Joint / Q000000981:diagnostic imaging / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D008970:Molecular Weight; D020370:Osteoarthritis, Knee / Q000150:complications / Q000000981:diagnostic imaging / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D012333:RNA, Messenger / Q000235:genetics; D011859:Radiography
chemical_list: D012333:RNA, Messenger; D002809:Chondroitin Sulfates; D016695:Glycosyltransferases
keywords: Cartilage; Chondrocyte; Chondroitin sulfate; Osteoarthritis