AB0723 SERUM LEVELS OF TRANSFORMING GROWTH FACTOR BETA1 AND SCLEROSTIN AND THEIR CORRELATIONS WITH MRI AND LABORATORY FINDINGS IN PATIENTS WITH SPONDYLOARTHRITIS

Abstract

Background:There is an actual demand for searching the biomarkers which could reflect disease activity and MRI changes in sacroiliac joints (SIJ) and spine in patients with spondyloarthritis (SpA). Transforming growth factor-beta 1 (TGF-β1) is a cytokine that suppresses inflammatory cytokines but could augment inflammation [1]. A very recent study suggests a possible role of sclerostin (Scl) in the identification of SpA patients, but further studies are needed to prove its role as a disease activity and progression biomarker [2]. In general, the role of these biomarkers in SpA patients remains unknown due to controversial data about their levels in patients with SpA in comparison with healthy subjects and correlations with SpA activity.Objectives:This study was designed to determine TGF-β1 and Scl serum levels and its correlations with changes in spine and SIJ on MRI imaging, laboratory parameters and indices of disease activity and functional status in SpA patients.Methods:102 patients with SpA (mean age (M±σ) - 38.1±11.2, 67 males and 35 females) and 15 healthy age- and gender-matched controls were included in the study. C-reactive protein (CRP, mg/l) and erythrocyte sedimentation rate (ESR, mm/hr) were evaluated as inflammatory markers. Disease activity and functional impairment were moderate to high, mean Ankylosing Spondylitis Disease Activity Score (ASDAS-CRP) was 3.07±1.07, Bath Ankylosing Spondylitis Disease Activity Index (BASDAI, mm) - 45.3±18.6, Bath Ankylosing Spondylitis Functional Index (BASFI, mm) - 31.7±22.9.Serum levels of TGF-β1 (pmol/l) and Scl (pmol/l) were measured by ELISA. Spine MRI imagines were assessed for active inflammatory lesions using Berlin method (0-69, n=19). Active and chronic MRI changes in SIJ were scored by Spondyloarthritis Research Consortium of Canada (SPARCC) score (0-72) and Danish scoring method (0-48), respectively (n=67). Spearman correlation coefficient and Student t-test were used for statistical analysis.Results:Mean value of laboratory and MRI parameters were: CRP – 20.9±31.5, ESR – 27.1±22.1, Berlin score was 3.93±3.87, SPARCC – 22.5±11.9, Danish score – 20.5±9.83.Patients with SpA had significantly lower serum levels of biomarkers compared with the healthy controls: 285.3±186.9 vs 443.2±84.3, p=0.0017 - for TGF-β1, and 21.7±13.5 vs 31.2±10.5, p<0.0001 – for Scl.There were significant positive correlations for TGF-β1: strong - with active spine lesions by Berlin method (r=0.810, p<0.01), and weak - with CRP level (r=0.224, p=0.024). There were no correlations with MRI inflammatory changes in SIJ.Scl had weak negative correlation with SPARCC (r=-0.265, p=0.030), but not with Danish or Berlin scores.There were no other correlations, including ASDAS-CRP, BASDAI and BASFI for both TGF- β1 and Scl.Conclusion:Serum TGF- β1 and Scl levels are significantly lower in SpA patients comparing with non-SpA subjects. TGF- β1 positively correlates with disease activity (CRP and active MRI lesions in spine), but has no correlations with SIJ inflammation assessed by MRI. Scl negatively correlates with inflammatory MRI changes in SIJ, but not in the spine.