Serum leptin concentration is increased in patients with Behcet's syndrome and is correlated with disease activity

Background Behcet's syndrome is a systemic, relapsing immuno-inflammatory disease with a generalized vasculitis of the microvasculature endothelial dysfunction. Leptin, a recently discovered neuroendocrine hormone, is a metabolic peptide that appears to be involved. Serum proinflammatory cytokines upregulate leptin levels and leptin itself directly induces nitric oxide production from endothelial cells with its specific receptors. Objectives To detect changes of serum leptin concentrations in patients with Behcet's syndrome compared with age- and sex-matched healthy volunteers by using enzyme-linked immunosorbent assay. We also investigated whether disease activity or the duration of Behcet's syndrome correlates with leptin concentration. Methods Thirty-five consecutive patients with Behcet's syndrome (41.2 +/- 8.4 years, 16 male, 19 female) and 20 age- and sex-matched healthy control subjects (40.4 +/- 10.91 years, nine male, 11 female) were included in this study. The body mass index (BMI) [weight (kg) height(-1) (m(2) )] was calculated for subjects at study enrolment. We measured serum leptin with a leptin enzyme immunoassay kit, and acute-phase reactants, including erythrocyte sedimentation rate, alpha(1) -antitrypsin, alpha(2) -macroglobulin and neutrophil count. The Mann-Whitney U -test was used for statistical analysis and P < 0.05 was considered significant. Values were expressed as mean +/- SD. Results The gender ratio, age and BMI were not substantially different among Behcet's patients and controls. The mean serum leptin concentrations in patients with Behcet's syndrome (16.8 +/- 7.49 ng mL(-1) ) were significantly (P < 0.001) higher than in healthy control volunteers (7.5 +/- 2.77 ng mL(-1) ). Active Behcet's patients had significantly (P = 0.001) higher leptin concentrations (20.5 +/- 7.99 ng mL(-1) ) when compared with patients in inactive periods (12.8 +/- 4.43 ng mL(-1) ). In addition, patients with longer disease duration (mean, 20.1 +/- 5.15 years) had also significantly (P = 0.013) higher leptin concentrations (20.2 +/- 8.52 ng mL(-1) ) than those with shorter disease duration (13.4 +/- 4.52 ng mL(-1) ) (mean, 7.4 +/- 3.29 years). All acute-phase reaction parameters were found to be significantly (for each, P < 0.01) increased in active disease. Conclusions Leptinmay have a role in modulating endothelial function and may be involved in mechanisms for vessel endothelium repair, during an exacerbation as well as in chronic disease.