Background Osteopontin (OPN) a member of specialized matricellular protein has pro-inflammatory and pro-fibrotic effects and binds integrin such as αvβ1 and αvβ3. Vitronectin (VTN), one of the integrin αvβ3 ligands, is a multifunctional glycoprotein that is present in blood and in the extracellular matrix. Decreased levels of VTN have been reported in patients with meningococcal disease, rheumatoid arthritis and Behçet's disease.
Objectives The aim of the present study was to evaluate serum OPN and VTN level in systemic sclerosis (SSc) and systemic lupus erythematosus (SLE).
Methods Eighty-six patients with SSc, 46 patients with SLE, and 38 healthy controls (HC) were enrolled in the study. The disease activity and severity scores in SSc group were determined by modified Rodnan skin score, Valentini activity index, Medsger disease severity index, and United Kingdom function score. In addition to routine laboratory parameters, OPN, VTN, interleukin-6, and transforming growth factor (TGF)-β levels were analyzed.
Results Serum OPN levels were higher in SSc and SLE groups compared to HC group (Table and Figure). However, OPN levels in SSc group were not associated with disease activity and severity scores (p>0.05). In addition, it was not correlated with SSc specific laboratory parameters, and capilleroscopic findings. On the other hand, serum VTN level was lower in the SSc group than in SLE and HC groups, while its level was similar in the SLE and HC groups (Table). Its level was negatively correlated with modified Rodnan skin score, visual analogue scales (physician and patient), lung-Medsger and heart-Medsger scores (r=-0.256, p=0.016, r=-0.450, p<0.001; r=-0.321, p=0.003; r=-0.319, p=0.003 and r=-0.245, p=0.023, respectively).
Conclusions OPN levels are increased in SSc and SLE. These results may suggest that OPN has not a specific role on fibrosis in SSc and that OPN level may be increases due to inflammatory process. On the other hand, serum VTN level decreases in SSc in contrast to SLE and it is negatively correlated with modified Rodnan skin score. Therefore, it may be concluded that VTN has anti-fibrotic action or the one cause of decreased serum VTN level in SSc may be the accumulation in fibrotic area.
Disclosure of Interest None declared