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Osteoprotegerin in sputum is a potential biomarker in COPD.
Chest. 2010 Dec 2;
Authors: To M, Ito K, Ausin PM, Kharitonov SA, Barnes PJ
Abstract BACKGROUND: Chronic obstructive pulmonary disease (COPD) is characterized by chronic airflow limitation and inflammation of the respiratory tract. Several inflammatory biomarkers have been evaluated in COPD but are poorly related to disease severity and progression. Osteoprotegerin (OPG) is a glycoprotein mediator that is expressed in the lung and macrophages so we have studied its concentration in induced sputum and macrophages of patients with COPD. RESULTS: OPG concentrations measured by ELISA in induced sputum of COPD patients (18.7± 18.6 ng/ml, n=39) were significantly higher than those of healthy smokers (8.1 ± 5.6 ng/ml, n=15), healthy non-smokers (3.5±3.8 ng/ml, n=14) or asthmatic patients (8.0 ±5.4 ng/ml, n=18). Sputum OPG levels in COPD negatively correlated with FEV(1) and positively correlated with RV/TLC (r=0.55, p<0.05), TL(CO) (r=-0.53, p<0.05) and K(CO) (r=-0.61, p<0.01). By contrast, sputum IL-8 concentrations in were related to disease severity but not to RV/TLC or gas diffusion. Airway macrophages and neutrophils were positive for OPG by immunocytochemistry in sputum and peripheral lung tissue. OPG induced matrix metalloproteinase-9 release from sputum macrophages in vitro. CONCLUSION: Sputum OPG may be a useful biomarker to monitor parenchymal destruction in COPD.
PMID: 21127170 [PubMed - as supplied by publisher]