Serum levels of inhibitors of wingless / beta-catenin in patients with ankylosing spondylitis and the relationship with anti-tumour necrosis factor alpha treatments

Aim: The primary aim of the study was to compare the serum levels of Dickkopf-1 (DKK-1) and sclerostin in patients with ankylosing spondylitis (AS) and healthy controls. The secondary aim was to evaluate the effects of anti-tumor necrosis factor alpha (TNF-α) treatments on levels of DKK-1 and sclerostin. The last aim was to evaluate any relationship between DKK-1, sclerostin, and radiologic progression in AS. Material and Method: We included 70 patients with AS (35 anti-TNF-α treated, 35 anti-TNF-α na？ve) and 31 healthy controls in this study. Serum DKK-1, sclerostin, C reactive protein, and erythrocyte sedimentation rate (ESR) were assessed in patients and healthy controls. The Ankylosing Spondylitis Disease Activity Score (ASDAS), Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), Bath Ankylosing Spondylitis Metrology Index (BASMI), and Bath Ankylosing Spondylitis Functional Index (BASFI) were calculated for the patients. Radiographs were scored according to the modified Stoke AS Spine Score (mSASSS) by an experienced radiologist who was blinded to the patients’ identity. Results: Patients with AS who were treated with anti-TNF-α agent had higher scores of BASMI and mSASSS compared with the anti-TNF-α na？ve patients. Serum levels of DKK-1 and sclerostin were significantly lower in patients with AS than in healthy controls. There was a negative correlation between DKK-1 levels with ASDAS and BASMI in patients with AS. There was no correlation between DKK-1 or sclerostin levels with mSASSS. There was a positive correlation between BASMI score with mSASSS in patients with AS. Conclusion: DKK-1 levels in patients with AS were negatively correlated with BASMI, on the other hand, BASMI had a strong positive correlation with mSASSS. Therefore, these findings suggest that lower DKK-1 levels in patients with AS may play a role in new bone formation