ACR Meeting Abstracts

ACR Meeting Abstracts

Abstract Number: 592

Two Novel Diagnostic Biomarkers of Cartilage Degradation and Connective Tissue Inflammation Are Predictive of Disease Progression in Ankylosing Spondylitis

Anne C. Bay-Jensen1, Stephanie Wichuk2, Inger Byrjalsen3, Zheng Zhao4, Robert GW Lambert5, Morten Asser Karsdal6 and Walter P. Maksymowych7, 1Cartilage Biomarkers and Research, Nordic Bioscience, Herlev, Denmark, 2Medicine, University of Alberta, Edmonton, AB, Canada, 3Research & Development, Nordic Bioscience, Herlev, Denmark, 4Department of Rheumatology, University of Alberta and PLA General Hospital, Beijing, PR China, Beijing, AB, China, 5Radiology, University of Alberta, Edmonton, AB, Canada, 6Nordic Bioscience A/S, Herlev, Denmark, 7Department of Medicine, University of Alberta, Edmonton, AB, Canada

Meeting: 2012 ACR/ARHP Annual Meeting

Keywords: ,

Session Information

Title: Spondylarthritis and Psoriatic Arthritis - Pathogenesis, Etiology

Session Type: Abstract Submissions (ACR)

Background/Purpose: Cartilage degradation and inflammation of synovial and connective tissue are key events in inflammatory arthropathies such as SpA. Presently there are no prognostic tools available for measuring these tissue related processes. Inflammation induces an increase in collagenases which lead to increased degradation of cartilage and synovial tissue. Type II collagen is the primary protein component of cartilage and type III collagen is one of the major proteins of synovial membrane. We aimed to investigate the diagnostic and prognostic utility of cartilage and synovial turnover biomarkers in AS.

Methods: Serum samples from patients with AS (n=124), RA (n = 47), and controls (n = 56) were assessed for type II and III collagen degradation using the C2M competitive ELISA and the C3M ELISA, respectively. Standard AS clinical outcome scores were collected: BASDAI (health questionnaire), hsCRP, and mSASSS. Progressors were defined as having new vertebral syndesmophytes over a two year period.  Logistic regression and CART were used to analyze the prognostic value of the markers individually or in combination.

Results: Both cartilage and connective tissue degradation fragments, C2M and C3M, were significantly elevated in serum samples from AS patients compared to healthy controls (P<0.0001). The area under the curves of C2M and C3M, respectively, were 70% and 81% for AS. C2M and C3M were also significantly elevated in RA patients compared to controls (P<0.0001). Diagnostic utility analyzed by ROC and AUCs were 72% and 89% for C2M and C3M, respectively. C3M correlated significantly with AS score BASDAI and mSASSS (p<0.01). C2M did not show the same correlations. A combination of the two markers could identify 80% of those who were defined as progressors and 61% of the non-progressors.

Conclusion: This study is the first to show that the two novel biomarkers of cartilage and synovial tissue degradation add additional information to the understanding of the diagnosis and progression of SpA.

Disclosure:

A. C. Bay-Jensen,
None;

S. Wichuk,
None;

I. Byrjalsen,
None;

Z. Zhao,
None;

R. G. Lambert,
None;

M. A. Karsdal,

Nordic Bioscience Diagnostic,

4;

W. P. Maksymowych,
None.

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