| Popis: |
Introduction: Joint destruction in rheumatoid arthritis (RA) involves infiltration and activation of osteoclasts. Human osteoclast progenitors (OCPs) exhibit chemotaxis and synovial compartment in RA expresses different chemokines. We aimed to define chemotactic signals by analyzing expression of chemokine receptors on OCPs, chemokine levels and to assess differentiation potential of OCPs. Materials and methods: Mononuclear cells were separated from peripheral blood of healthy controls and RA patients. Phenotype of OCPs (CD3-CD19-CD56- CD11b+CD14+) was determined using flow cytometry for following chemokine receptors: CCR1, CCR2, CCR4, CXCR4. Chemokine ligand concentrations (CCL2, CCL3, CCL4, CCL5, CXCL9, CXCL10) were measured in serum and synovial fluid using flow cytometry bead based array. OCPs were sorted and cultured with M-CSF and RANKL. After two weeks, cells were stained for TRAP enzyme and positive, mature, osteoclasts were counted. Results: Human peripheral blood OCPs similarly expressed chemokine receptors CCR1, CCR2, CCR4 and CXCR4 in RA and healthy subjects. However, CCL2, CXCL9 and CXCL10 serum levels were higher in RA, while CCL4 and CXCL10 concentrations were significantly higher in synovial fluid compared to RA serum levels. Cell culture revealed no significant differences between RA and control group. Conclusions: Although differentiation potential and receptor expression of RA OCPs is similar to control, levels of several chemokines are upregulated, indicating a possible chemotactic mechanism of OCP migration to affected joints specifically associated with RA. In parallel, we are determining the cell population responsible for increased chemokine production, most probably of the monocyte/macrophage lineage, which is induced in RA by chronic inflammation. |
