The study of angiogenesis in early rheumatoid arthritis--clinical, immunohistochemical and immunological correlations

The objective of the study was to analyze several immunohistochemical, histological, and morphometrical aspects of angiogenesis in early rheumatoid arthritis synovium. We aimed to identify possible correlations between the histological and immunohistochemical patterns and the serum levels of VEGF, as well as with clinical and biological markers of disease activity.

35 patients with early rheumatoid arthritis below 12 months from the onset, naive for DMARDs, underwent clinical standard examination as well as serum determinations for CRP, RF. anti-CCP2 antibodies and VEGF. DAS28 value has been determined for each patient in order to assess the disease activity. We performed biopsy sampling through arthroscopy, the synovium fragments beeing histopathologically processed, in order to elaborate a total histological score. Immunohistochemical analysis has been performed with quantification of synovial VEGF, VEGF-R1 and CD34 expression. Standard and activated microvascular density (sMVD and aMVD) have been evaluated through double immunostaining (CD34/ VEGF-R1).

VEGF and VEGF-R1 have been identified with high prevalence in endothelial cells, in lining and sublining synovial cells, as well as in inflammatory cells. The study focuses on the analysis of aMVD, a valuable parameter, representative for active angiogenesis, which proved to correlate significantly with the serum levels of VEGF, the composite histological score as well as with VEGF-R1 and DAS28.

The statistic analysis of the data support VEGF-R1 and aMVD as markers with predictive value regarding activity and progression in early stages of rheumatoid arthritis. The validation of preliminary conclusions oblige to continuous research through extending the study group and inclusion of several others biomarkers involved in synovial angiogenesis.