Study findings published in the journal Rheumatology International suggest that the adipocyte-secreted hormone leptin predicts the severity of rheumatoid arthritis (RA).
The progression of RA is closely linked to the production of inflammatory cytokines such as tumor necrosis factor-α, a key source of which is white adipose tissue. The anorexigenic hormone leptin is also produced by adipose tissue and animals lacking the hormone are less susceptible to the development of inflammatory disorders.
Hypothesizing, therefore, that leptin might predict the progression of RA, a team from the Medical University of Lublin in Poland, led by Bozena Targonska-Stepniak, studied leptin concentrations, nutritional status, and disease severity in 37 RA patients.
The investigators found that, although leptin levels were generally within the normal physiological range, they were significantly higher in patients with erosive RA than in those with non-erosive disease.
In addition, among those who had suffered RA for over 10 years, leptin concentrations significantly predicted disease severity, with levels significantly higher in patients with higher disease activity, as shown by a score below 5.1 on the 28 joints disease activity score system (DAS28).
Serum leptin concentrations also positively correlated with erythrocyte sedimentation rate, and the number of tender joints.
Interestingly, leptin concentration was related to body mass index but only in women.
Regarding their findings, the clinicians note that "exacerbations do occur in the course of chronic RA and are associated with excessive production of pro-inflammatory cytokines and probably leptin, which could explain higher leptin levels in the course of exacerbated disease."
Recommending further research they conclude "that some important dependence exists between the risk of aggressive course of RA and increased leptin levels."