Serum osteopontin level in scleroderma

ABSTRACT SERUM OSTEOPONTIN LEVEL IN SCLERODERMA Osteopontin (OPN) (also known as early T lymphocyte activation 1 [ETA-1] is a member of specialized matricellular proteins or extracellular matrix has pro-inflammatory and pro-fibrotic effects such as cell-matrix communication, the transfer of T lymphocytes message, leukocyte adhesion to endothelium and the migration regulation of macrophage function with chemotactic feature apart from bone mineralization. Thus, OPN inhibition in experimental studies has been shown to prevent the development of fibrosis. In this research, the OPN levels in SSc patients and the relationship between the OPN levels and disease activity and disease severity scores were aimed to investigate. Eighty-six SSc patients, 46 systemic lupus erythematosus (SLE) patients (patient control group), and 38 healthy volunteers were enrolled in the study. The disease activity and severity scores in SSc group were determined by modified Rodnan skin score, Valanetini activity index, Medsger disease severity index, and United Kingdom function score. In addition to routine laboratory parameters OPN, interleukin-6, transforming growth factor-β (TGF-β), and vitronectin levels were analyzed. Compared with the control group, OPN levels were higher in SSc and SLE groups (for both; p<0.001). However, OPN levels in SSc group were not associated with disease activity and severity scores (p>0.05). Compared other groups, TGF-β levels in SSc were found significantly higher, however, there was no significant difference between OPN and TGF-β serum levels (p>0.05). In addition, there was no correlation between OPN levels, SSc specific laboratory parameters, and capilleroscopic findings. As a result, OPN levels in chronic autoimmune diseases such as SSc and SLE are increased. Contrary to common information, OPN is not a specific cytokine involved at the stage of fibrogenesis in SSc. OPN probably effects as a part of the acute inflammatory response by regulation of macrophages and T-cells chemotaxis. Keywords: osteopontin, scleroderma, acute inflammation, fibrogenesis.