SAT0404 Relationship of sclerostin and DICKKOPF-1 serum levels with disease activity and inflammatory MRI lesions in patients with spondyloarthritis
Authors: I Shynkaruk, O Iaremenko, D Fedkov, K Iaremenko
Journal: Annals of the Rheumatic Diseases (2017)

<h3>Background</h3> Dickkopf-1 (Dkk-1) and sclerostin (Scl) are likely to play important roles in the process of ankylosis in Spondyloarthritis (SpA) [1]. Their serum levels are associated with the formation of new syndesmophytes [2]. But the relationship between these biomarkers and disease activity including active inflammatory lesions in sacroiliac joints (SIJ) on magnetic resonance imaging (MRI) still not clear. <h3>Objectives</h3> To estimate the relationship between the Scl and Dkk-1serum levels and active inflammatory MRI lesionsin SIJ, disease activity and functional status in SpA patients (pts). <h3>Methods</h3> Serum levels of Scl and Dkk-1 (pmol/l; ELISA) were measured at baseline in 79 pts with SpA. Mean age of pts (63.3% male) was 37.5±11.3, mean disease duration – 10.7±9.44 yrs. Radiological sacroiliitis defined according to Kellgren grade was: 0 – 1.6%, I – 22%, II – 49.2%, III – 13.6% and IV – 13.6%. Active inflammatory lesions in SIJ were evaluated with Spondyloarthritis Research Consortium of Canada (SPARCC) MRI SIJ score (0–72, n=46). Disease activity was measured by Ankylosing Spondylitis Disease Activity Score (ASDAS) using C-reactive protein (CRP), Bath Ankylosing Spondylitis Disease Activity Index (BASDAI, mm), CRP (mg/l) and erythrocyte sedimentation rate (ESR, mm/hr). Functional status estimated using Bath Ankylosing Spondylitis Functional Index (BASFI, mm). For correlation the Spearman correlation coefficient was calculated. <h3>Results</h3> Mean value (M±σ) of biomarkers in all SpA pts were: Scl – 19.2±11.63, Dkk-1 – 30.7±19.5. The mean value of indices and laboratory parameters in all SpA pts were: ASDAS-CRP – 3.01±1.09, BASDAI – 4.36±1.88, CRP – 20.3±33.0, ESR – 25.8±20.7, BASFI – 3.01±2.33. SPARCC score was 24.6±10.9. Scl level was significantly higher in pts with lower activity by SPARCC score (23.1±12.7) vs higher activity (16.6±7.63), p=0.043, in pts with moderate disease activity by ASDAS-CRP (22.3±15.6) vs very high disease activity (14.6±9.89), p=0.031, and in women (23.1±12.6) vs men (16.9±10.5), p=0.014. Its level didn9t depend on CRP, ESR, BASDAI, BASFI and HLA B27 positivity. Scl showed significantly negative correlation with BASDAI (r=-0.381, p=0.041) only in women. There was no difference in Dkk-1 serum level depending on the gender, disease activity (by ASDAS-CRP), functional status, the presence of HLA B27 and inflammatory changes in SIJ (with quartile distribution). But the correlation analysis showed significant relationship of Dkk-1 with CRP (r=0.243, p=0.031) and SPARCC MRI SIJ score (r=0.351, p=0.017). The strength of the correlation between Dkk-1 and CRP was slightly higher in HLA B27 positive pts (90%; r=0.334, p=0.018). In SpA pts with lower activity by SPARCC score significant correlation between Dkk-1 and inflammatory lesions in SIJ (r=0.400, p=0.043) and a negative correlation between Dkk-1 and BASDAI (r=-0.513, p=0.017) were found. There was no correlation between Scl and Dkk-1 levels among all pts and different subgroups. <h3>Conclusions</h3> Scl level is significantly higher in pts with lower disease activity by SPARCC MRI SIJ score and ASDAS-CRP. Dkk-1 significantly positively correlates with disease activity due to CRP level and SPARCC score, but not to BASDAI. <h3>References</h3> Xie W. Ann N Y Acad Sci. 2016 Jan; 1364: 25–31. Song I-H. Ann Rheum Dis. 2011 Jul 1; 70(7): 1257–1263. <h3>Disclosure of Interest</h3> None declared