[Expression of peroxisome proliferator-activated receptor-gamma coactivator 1β in synovium in patients with rheumatoid arthritis and its clinical significance].

Objective

To investigate the expression of peroxisome proliferator-activated receptor-gamma coactivator (PGC)1β in synovium of patients with rheumatoid arthritis (RA) and its association with histological synovitis.

Methods

This cross-sectional study recruited RA patients at the Department of Rheumatology, Sun Yat-Sen Memorial Hospital from May 2010 to October 2016. Clinical data were collected. Conventional radiographs of bilateral hands and wrists were performed and assessed according to Sharp/van der Heijde-modified Sharp score(mTSS). Synovial tissues from knee joints of all RA patients were obtained by biopsies, and then stained with HE and immunohistochemically for PGC-1β, CD3, CD20, CD38, CD68, CD15 and CD34 to evaluate synovitis, synovial PGC-1β expression and the densities of inflammatory cells and endothelial cells. The relationship between synovial PGC-1β expression and histological synovitis, disease activity and joint destruction in RA was analyzed by Spearman's rank correlation and multivariate linear regression.

Results

There were 83 RA patients recruited with 20 (24.1%) males and 63 (75.9%) females, aged (54±14) years. PGC-1β expressed in the nuclei of lining synoviocytes, sublining inflammatory cells and vascular endothelial cells of RA synovium. The percentage of synovial PGC-1β+cells was positively correlated with histological synovitis score (r=0.333) and the densities of sublining CD3+ T cells (r=0.259), CD20+ B cells (r=0.320), CD38+plasma cells (r=0.342) and CD68+ macrophages (r=0.309)(all P<0.05). It was also positively correlated with erythrocyte sedimentation rate, C reactive protein and total mTSS (r=0.219-0.301, all P<0.05). Multiple linear regression analysis further confirmed the positive correlation between the percentage of synovial PGC-1β+cells and mTSS (β=0.312, P=0.004).

Conclusion

Synovial PGC-1β is positively associated with local and systemic inflammation as well as joint destruction, which implies that PGC-1β might involve in the pathogenesis of synovitis and joint destruction in RA.