Background Synovial angiogenesis is considered to be an important early step in the pathogenesis of rheumatoid arthritis (RA) and in the perpetuation of disease.¹ Because angiogenesis and formation of new blood vessels is a component of pannus in RA, we hypothesized that the balance between angiopoietin-1(Ang1) and angiopoietin-2 (Ang2) is in favor of Ang2 (represented by Ang2/Ang1 ratio) in RA pannus.

Objectives To evaluate the serum levels of Ang1, Ang2 as well as the significance of Ang2/Ang1 ratio in RA in relation to blood flow signals in total of 10 joints and RA activity parameters. In addition, we studied their relevance to predict the state of angiogenesis.

Methods This study was conducted on 65 consecutive very early RA patients. Power Doppler ultrasonography (PDUS) was performed in a total of 10 joints: the bilateral elbows, wrists, metacarpophalangeal, knees, and ankles. The blood flow signals at various sites of the synovial membrane of each joint were scored on a 3- grade scaling system. The score at the site with the strongest finding in each joint was adopted as the score of the joint, and the total of the scores of the 10 joints was defined as the total signal score (TSS). On the same day, Serum variables including serum VEGF, Ang1, and Ang2 levels as well as clinical disease activity were evaluated. All measured parameters were reassessed after one month.

Results Serum VEGF and serum Ang2 levels as well as Ang2/Ang1 ratio were significantly correlated with CRP and DAS28-CRP at baseline and one month after. While, serum Ang1 level did not correlate with the indices of disease activity. Additionally, serum VEGF and Ang2 levels and Ang2/Ang1 ratio were significantly correlated with TSS at baseline and after one month. Moreover, significant correlations were noted between serum VEGF and level of Ang2 and Ang2/Ang1 ratio both at baseline and one month later. Serum Ang1 level was significantly inversely correlated with Ang2/Ang1 ratio in contrast to serum Ang2 level which correlated significantly with Ang2/Ang1 ratio at baseline and after one month. Interestingly baseline serum VEGF level was significantly correlated with TSS after one month. Also, baseline Ang2/Ang1 ratio was significantly correlated with TSS after one month.

Conclusions Serum concentrations of VEGF and Ang2 as well as Ang2/Ang1 ratio were correlated with parameters of inflammation in early RA. Our results demonstrate that the elevated serum VEGF and Ang2/Ang1 ratio (in favor of Ang2) reflect a phase of vigorous angiogenesis.

References

1. Taylor PC. Serum vascular markers and vascular imaging in assessment of rheumatoid arthritis disease activity and response to therapy. Rheumatology 2005;44:721–728

Disclosure of Interest None Declared