RT Journal Article
SR Electronic
T1 Nuclear Factor-κB–inducing Kinase Is Expressed in Synovial Endothelial Cells in Patients with Early Arthritis and Correlates with Markers of Inflammation: A Prospective Cohort Study
JF The Journal of Rheumatology
JO J Rheumatol
FD The Journal of Rheumatology
SP 1573
OP 1581
DO 10.3899/jrheum.150245
VO 42
IS 9
A1 Karen I. Maijer
A1 Ae Ri Noort
A1 Maria J.H. de Hair
A1 Christiaan van der Leij
A1 Katinka P.M. van Zoest
A1 Ivy Y. Choi
A1 Daniëlle M. Gerlag
A1 Mario Maas
A1 Paul P. Tak
A1 Sander W. Tas
YR 2015
UL http://www.jrheum.org/content/42/9/1573.abstract
AB Objective. The nuclear factor-κB (NF-κB) family of transcription factors is strongly involved in synovial inflammation. We have previously shown that NF-κB–inducing kinase (NIK) is a key regulator of inflammation-induced angiogenesis in rheumatoid arthritis (RA) synovial tissue (ST). Here, we investigated synovial NIK expression in patients with early arthritis and in autoantibody-positive individuals at risk of developing RA.Methods. ST biopsies were obtained by arthroscopy from 154 patients with early arthritis (duration < 1 yr) with various diagnoses and 54 IgM rheumatoid factor–positive and/or anticitrullinated protein antibodies–positive individuals without evidence of arthritis. ST was stained for NIK and endothelial cell (EC) markers. Additionally, measures of disease activity were collected and contrast-enhanced magnetic resonance imaging (MRI) was performed in a subset of these patients.Results. In patients with early arthritis, NIK was predominantly expressed in EC of small blood vessels. Further, NIK expression correlated with erythrocyte sedimentation rate (r 0.184, p = 0.024), C-reactive protein (r 0.194, p = 0.017), joint swelling (r 0.297, p < 0.001), synovial immune cell markers (lining r 0.585, p < 0.001; sublining macrophages r 0.728, p < 0.001; T cells r 0.733, p < 0.001; and B cells r 0.264, p = 0.040), MRI effusion (r 0.665, p < 0.001), MRI synovitis (r 0.632, p < 0.001), and MRI total score (r 0.569, p < 0.001). In 18.5% of autoantibody-positive individuals, ST NIK+EC were present, but this was not predictive of the development of arthritis.Conclusion. NIK+EC are present in the earliest phase of synovial inflammation and may be indicative of high angiogenic activity in the inflamed ST. Therefore, NIK+EC may play an important role in the persistence of synovitis. Collectively, our data underscore the importance of angiogenesis in synovial inflammation and identify NIK as a potential therapeutic target in arthritis.