Arthritis & Rheumatism, Volume 62,
November 2010 Abstract Supplement
Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Atlanta, Georgia November 6-11, 2010.
MMP-3 and DKK-1 Levels in Juvenile Idiopathic Arthritis.
Stoll2, Matthew L., Christadoss2, Michelle L., Punaro2, Marilynn G., Olsen1, Nancy J.
MMP-3 and DKK-1 are markers of cartilage and bone breakdown, respectively. Prior studies in children and adults with arthritis have shown that MMP-3 levels are elevated and correlate with markers of disease activity(1,2). In RA, DKK-1 has been shown to be a marker of radiographic progression(3). There are no published studies of DKK-1 levels in children, healthy or otherwise.
For DKK-1 measurements, serum was obtained from 29 children with oligoarticular JIA and 11 healthy control subjects. For MMP-3 measurements, serum was obtained from 67 children with JIA and 12 healthy control subjects. MMP-3 and DKK-1 values were measured through ELISA assays using kits provided by the manufacturer (Alpco).
MMP-3 levels were significantly elevated in each JIA subtype as compared to the healthy controls (Figure 1), and among JIA patients showed a modest but statistically significant correlation with joint count (r = 0.294, p = 0.007) and ESR (r = 0.344, p = 0.005) at the time of the study. Differences between the arthritis sub-groups were not statistically significant. 8/27 oligoarticular JIA children, but none of the other arthritis patients, had undetectable MMP-3 levels (p = 0.004); this difference remained significant when the three subjects in long-term remission, all of whom had undetectable levels, were excluded (p = 0.032). One subject thought to be a healthy control based upon her physical exam had an elevated MMP-3 level, and subsequently had an MRI and physical exam that were consistent with inflammatory arthritis. Another subject thought to have oligoarticular JIA had negative MMP-3 levels; MRI revealed a synovial cyst.
DKK-1 levels were only measured in oligoarticular JIA patients and healthy controls. Values were comparable, with median levels of 25.3 (IQR 22.836.6) and 27.9 ng/ml (IQR 22.530.4) in patients and controls, respectively (p = 0.942). These levels were an order of magnitude higher than those reported in most prior studies in adults(4,5). There was no association with DKK-1 levels and the age of the child.
Measurement of serum MMP-3 may be a useful biomarker in children with an unclear presentation of joint pain and may help assess severity of the condition. However, perhaps because growing children have considerable bone turnover at baseline, DKK-1 may be a less useful biomarker in this population as compared to adults.
To cite this abstract, please use the following information:
Stoll, Matthew L., Christadoss, Michelle L., Punaro, Marilynn G., Olsen, Nancy J.; MMP-3 and DKK-1 Levels in Juvenile Idiopathic Arthritis. [abstract]. Arthritis Rheum 2010;62 Suppl 10 :1491