Histomorphologic and Histomorphometric Characteristics of Zygapophyseal Joint Remodeling in Ankylosing Spondylitis. Issue 7 (July 2014)

• Record Type: Journal Article
• Authors: Bleil, Janine; Maier, Rene; Hempfing, Axel; Schlichting, Uwe; Appel, Heiner; Sieper, Joachim; Syrbe, Uta
• Is Part Of: Arthritis & rheumatology. Volume 66:Issue 7(2014)
• Page Start: 1745
• Page End: 1754
• Publication Date: 2014-07
• Subjects: Arthritis -- Periodicals; Rheumatism -- Periodicals; 616.72
• DOI: 10.1002/art.38404
• Languages: English
• ISSNs: 2326-5191

Abstract

<abstract abstract-type="main"> <title> <x xml:space="preserve">Abstract</x> </title> <sec id="art38404-sec-0001" sec-type="section"> <title>Objective</title> <p>To unravel the mechanisms that control bony ankylosis in ankylosing spondylitis (AS).</p> </sec> <sec id="art38404-sec-0002" sec-type="section"> <title>Methods</title> <p>Histomorphologic and histomorphometric analyses were performed on zygapophyseal joints obtained from 18 patients with AS, 9 patients with osteoarthritis (OA), and 10 cadaver donors without a rheumatic disease (controls). The proteoglycan content of the cartilage was determined by Safranin O staining and the chondrocyte apoptosis according to caspase 3 expression.</p> </sec> <sec id="art38404-sec-0003" sec-type="section"> <title>Results</title> <p>AS joints were categorized into 3 groups according to the morphology of the joint surfaces and joint space: group 1 were joints with an open joint space, group 2 were joints with cartilaginous fusion, and group 3 were joints with bony fusion of the joint surfaces. Progressive loss of the joint space from group 1 joints to group 3 joints suggests that this grouping corresponds to sequential stages of joint remodeling. Cartilage thickness and subchondral bone plate thickness declined from group 1 to group 3 (<italic>P</italic> < 0.01). Increased chondrocyte apoptosis rates were found in groups 1 and 2 (<italic>P</italic> < 0.05), while in group 3, a reduction in the proteoglycan content was found (<italic>P</italic> < 0.001). Bone marrow replacement and invasion of the subchondral bone plate by fibrous tissue was found predominantly in AS joints in group 2.</p> </sec> <sec id="art38404-sec-0004" sec-type="section"> <title>Conclusion</title> <p>Cartilage degeneration, indicated by cartilage thinning, enhanced chondrocyte apoptosis, and proteoglycan loss, and subchondral bone thinning, promoted by invasion of the subchondral bone plate by a fibrous tissue originating from the bone marrow, are hallmarks of joint remodeling in AS.</p> </sec> </abstract>