Plasma leptin and adiponectin in COPD exacerbations: Associations with inflammatory biomarkers

Background: Various systemic inflammatory markers have been evaluated for their value in acute exacerbations of chronic obstructive pulmonary disease (COPD). Leptin and adiponectin have been linked to acute exacerbations and stable COPD. Objectives: To assess plasma leptin, adiponectin and their ratio in acute exacerbations of COPD and to study possible associations with inflammatory biomarkers. Methods: Plasma leptin, adiponectin and their ratio (L/A) and serum biomarkers of systemic inflammation C-reactive protein (CRP), Tumor necrosis factor alpha (TNF-alpha) and interleukin-6 (IL-6) were assessed at three time points (admission, resolution and stable phase - 8 weeks after resolution) in a selected cohort of 63 COPD patients hospitalized for acute exacerbations. Subjects with comorbidities related to adipose tissue hormones were meticulously excluded. Measurements and main results: All systemic inflammatory biomarkers, leptin and L/A ratio were elevated during admission compared to resolution and stable phase (mean L/A ratio 2.6 vs. 1.57 vs. 1.22, respectively; p < 0.0001), whereas adiponectin was elevated at resolution compared to admission. Log leptin, adiponectin and L/A ratio were significantly associated with variables of systemic inflammation, after proper adjustments, both on admission and in stable condition. In stepwise multiple linear regression models, IL-6 and TNF-alpha present the most significant associations with leptin, adiponectin and their ratio. Conclusions: Our data suggest that both leptin and adiponectin are associated with the systemic inflammatory process during exacerbations of COPD. The most significant associations seem to be those with IL-6 and TNF-alpha. (C) 2009 Elsevier Ltd. All rights reserved.