Phenotypic characterization and invasive properties of synovial fluid-derived adherent cells in rheumatoid arthritis

Abstract

The present study aimed at characterizing the phenotype and functions of adherent synovial fluid (SF) cells derived from rheumatoid arthritis (RA), comparing with fibroblast-like synoviocytes (FLS) derived from RA synovial tissue (ST). Adherent SF-derived cells were spindle-shaped from passages 1-6 under light microscopy. The cell surface marker profile in SF-derived cells from passage 1-6 was similar to that of ST-derived FLS. Levels of MMP-1 and MMP-3 were not significantly different between SF-derived cells and ST-derived FLS (p = 0.20 and p = 0.40, respectively). There was no significant difference in the optical density value between two cell types in the cell invasion assay (p = 0.10). SF-derived adherent cells have a fibroblast-like phenotype from very early culture passages and have the potential to produce MMPs with the invasive capacity to degrade cartilage, identical to ST-derived FLS. Therefore, these cells could substitute for ST-derived FLS in studying the pathogenesis of RA.