title: Serum cathepsin K levels of patients with longstanding rheumatoid arthritis: correlation with radiological destruction.
abstract: Cathepsin K is a cysteine protease that plays an essential role in osteoclast function and in the degradation of protein components of the bone matrix by cleaving proteins such as collagen type I, collagen type II and osteonectin. Cathepsin K therefore plays a role in bone remodelling and resorption in diseases such as osteoporosis, osteolytic bone metastasis and rheumatoid arthritis. We examined cathepsin K in the serum of 100 patients with active longstanding rheumatoid arthritis. We found increased levels of cathepsin K compared with a healthy control group and found a significant correlation with radiological destruction, measured by the Larsen score. Inhibition of cathepsin K may therefore be a new target for preventing bone erosion and joint destruction in rheumatoid arthritis. However, further studies have to be performed to prove that cathepsin K is a valuable parameter for bone metabolism in patients with early rheumatoid arthritis.
authors.affiliation: Institut für Rheumatologie der Kurstadt Baden in Kooperation mit der Donauuniversität Krems, Austria. martin.skoumal@a1.net
authors.forename: Martin
authors.initials: M
authors.lastname: Skoumal
authors.forename: Günther
authors.initials: G
authors.lastname: Haberhauer
authors.forename: Gernot
authors.initials: G
authors.lastname: Kolarz
authors.forename: Gerhard
authors.initials: G
authors.lastname: Hawa
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Woloszczuk
authors.forename: Anton
authors.initials: A
authors.lastname: Klingler
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000974:Antibodies, Antinuclear / Q000097:blood; D018501:Antirheumatic Agents / Q000627:therapeutic use; D001172:Arthritis, Rheumatoid / Q000097:blood* / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000473:pathology; D001327:Autoimmune Diseases / Q000097:blood* / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000473:pathology; D015415:Biomarkers; D001799:Blood Sedimentation; D016723:Bone Remodeling; D001862:Bone Resorption / Q000097:blood* / Q000000981:diagnostic imaging; D001842:Bone and Bones / Q000000981:diagnostic imaging*; D002097:C-Reactive Protein / Q000032:analysis; D056657:Cathepsin K; D002403:Cathepsins / Q000097:blood*; D005260:Female; D006454:Hemoglobins / Q000032:analysis; D006801:Humans; D008297:Male; D008875:Middle Aged; D010976:Platelet Count; D011859:Radiography; D012720:Severity of Illness Index
chemical_list: D000974:Antibodies, Antinuclear; D018501:Antirheumatic Agents; D015415:Biomarkers; D006454:Hemoglobins; D002097:C-Reactive Protein; D002403:Cathepsins; C534130:CTSK protein, human; D056657:Cathepsin K