Baseline serum adipokine levels predict radiographic progression in early rheumatoid arthritis

Abstract

Adipose tissue can secrete soluble mediators (adipokines) with potent immune regulatory functions. Some adipokines have been previously associated with radiographic damage in patients with rheumatoid arthritis (RA). In the present study, we investigated the capacity of baseline adipokine levels to predict radiographic progression over a period of 4 years and studied their contribution relative to that of other known risk factors, such as anti-cyclic citrullinated peptide (anti-CCP) antibodies. Serum concentrations of leptin, visfatin, resistin, adiponectin, adipsin, tumor necrosis factor α (TNFα), and interleukin-6 (IL-6) were determined in serum samples obtained at baseline from 253 patients with RA from the Early Arthritis Cohort. The association between levels of these adipokines and radiographic progression was determined using a multivariate normal regression model correcting for age, sex, treatment strategy, body mass index (BMI), and the presence of anti-CCP antibodies. Levels of IL-6, TNFα, visfatin, and adiponectin were positively associated with radiographic progression over 4 years. This association was independent of BMI. However, only adiponectin levels remained significantly associated with radiographic progression when the model was corrected for the presence of anti-CCP antibodies, whereas a trend was observed for IL-6. The association of both TNFα and visfatin with radiographic damage disappeared after correction for the presence of anti-CCP antibodies, which is consistent with the fact that the levels of both cytokines correlated significantly with anti-CCP antibody levels in these patients. Our results indicate that adipokines are predictors of radiographic progression in RA, possibly through distinct underlying biologic mechanisms.