Assessment of leptin and resistin levels in patients with chronic obstructive pulmonary disease

INTRODUCTION Chronic obstructive pulmonary disease (COPD) is the most common chronic lung disease in the world. The increasing severity of inflammatory processes in the respiratory tract leads to exacerbation of COPD. This process may be associated with changes in the synthesis of adipokines, the peptides that participate in immune processes. 
OBJECTIVES The aim of this study was to identify more sensitive and specific laboratory markers useful in diagnosing inflammatory processes in patients with COPD. 
PATIENTS AND METHODS The study involved 33 patients with COPD without exacerbation. During the previous year, 1 episode of exacerbation was reported in 15 patients and no exacerbations were reported in the remaining 18 patients. Serum concentrations of adipokines were measured using an enzyme‑linked immunosorbent assay (ELISA). 
RESULTS In patients with COPD, we observed a 2‑fold increase in leptin levels compared with healthy controls (18.8 ±10.2 ng/ml vs. 9.06 ±4.33 ng/ml; P = 0.042). Mean resistin levels in these patients were also 2‑fold higher than those in controls (8.24 ±4.18 ng/ml vs. 3.58 ±1.51 ng/ml, respectively; P = 0.027). Significant positive correlations between C‑reactive protein (CRP) and leptin as well as CRP and resistin levels were observed in patients with COPD (r = 0.75 and r = 0.83, respectively; P <0.05). Moreover, a statistically significant negative correlation between the forced expiratory volume in 1 second (FEV1) and resistin was noted in this group (r = 0.62; P <0.05). There was no correlation between FEV1 and leptin levels either in patients with COPD or in healthy controls. 
CONCLUSIONS A significant increase in leptin and resistin levels in patients with COPD may suggest that these adipokines are involved in the inflammatory process underlying the disease.