A study on vascular endothelial growth factor and endothelin-1 in patients with extra-articular involvement of rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease associated with a wide range of extra-articular manifestations. Recent studies emphasise a key inflammatory role of the endothelial cells, either by overexpression of inflammatory mediators or by the proliferation of new blood vessels, in the disease process leading to the systemic organ involvement. To evaluate the relationship between internal organ manifestations and immunological markers of endothelial activation, serum levels of vascular endothelial growth factor (VEGF) and endothelin-1 (ET-1) were determined by an enzyme-linked immunosorbent assay in 64 RA patients and in 32 healthy controls. In comparison with a control group, higher serum concentrations of VEGF and ET-1 (p<0.001) in RA patients were demonstrated. A comparison between both RA groups with (20 patients) and without systemic involvement (44 patients) showed significantly higher concentrations of VEGF (p<0.05) and ET-1 (p<0.01) in the sera of patients with systemic manifestation. Moreover, a significant positive correlation between VEGF and ET-1 (r=0.475, p<0.001) in RA patients was found. A positive correlation between VEGF and Disease Activity Score (DAS) 28 index (r=0.39, p<0.005) as well as erythrocyte sedimentation rate (ESR) (r=0.564, p<0.0001) and C-reactive protein was found. ET-1 serum level correlated significantly with ESR (r=0.326, p<0.05) and DAS 28 index (r=0.307, p<0.05). These results suggest that the elevated serum levels of VEGF and ET-1 are associated with systemic organ involvement in RA patients and may play a key role in the pathogenesis of extra-articular manifestation of the disease.