Elevated Serum Levels of Sclerostin are Associated with High Disease Activity and Functional Impairment in Patients with Axial Spondyloarthritis.

BACKGROUND: Recent research suggests that biomarkers may be useful in assessing disease activity, structural damage, and response to therapy in axial spondyloarthritis (axSpA). Our study aims at evaluating the relationship between inflammation and bone remodeling markers and variables assessing disease activity and functional disability in patients with axSpA. METHODS: Serum levels of sclerostin, matrix metalloproteinase-3 (MMP-3), interleukin-17 (IL-17), and IL-23 were measured in 60 patients with axSpA and 20 healthy controls. Disease activity was evaluated using Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), Ankylosing Spondylitis Disease Activity Score (ASDAS), C-reactive protein (CRP), and erythrocyte sedimentation rate (ESR). Functional status was assessed by Bath Ankylosing Spondylitis Function Index (BASFI) and measures of spinal mobility. RESULTS: Sclerostin levels were more elevated in axSpA patients with high disease activity than in those with low disease activity and in controls. They were significantly correlated with BASFI values (r = 0.29, p = 0.03) and measures of spinal mobility, but not with the classical markers of disease activity (BASDAI, ASDAS, CRP, and ESR). Although both MMP-3 and IL-17 levels were elevated in patients with active disease, they were not correlated with markers of disease activity or with functional disability. The levels of sclerostin, MMP-3, IL-17, and IL-23 were similar in axSpA patients and healthy controls. CONCLUSIONS: Elevated levels of sclerostin, MMP-3, and IL-17 were observed in axSpA patients with active disease, suggesting their potential role in assessing disease activity. In axSpA patients, sclerostin levels might be equally influenced by inflammation and level of physical activity. Further studies are required to confirm our findings in order to understand their clinical value.