Upregulation of thrombospondin 1 expression in synovial tissues and plasma of rheumatoid arthritis: Role of transforming growth factor-?1 toward fibroblast-like synovial cells

Abstract

Objective. To investigate the role of thrombospondin 1 (TSP-1) in RA. Methods. Expression of TSP-1 in synovial tissues was determined by immunohistochemistry. Expression of TSP-1 in rheumatoid fibroblast-like synovial cells (FLS) was investigated by quantitative real-time PCR and ELISA. Correlations among the plasma TSP-1 and other variables in patients with RA were examined. Results. Expression of TSP-1 was increased in rheumatoid synovial tissues. Transforming growth factor-?1 (TGF-?1) clearly increased TSP-1 expression in FLS on both mRNA and protein levels. Changes in plasma TSP-1 were associated with those in 28-joint Disease Activity Score-erythrocyte sedimentation rate and plasma TGF-?1. Conclusion. TSP-1 might be critically involved in the disease process of RA through the TGF-?1/ TSP-1 axis.