Severity of chronic obstructive pulmonary disease with 'exacerbator with emphysema phenotype' is associated with potential biomarkers

Objective The present study was designed to investigate the biomarkers levels of fractalkine (FKN), neutrophil elastase (NE) and matrix metalloproteinase-12 (MMP-12) in chronic obstructive pulmonary disease (COPD) with 'exacerbator with emphysema phenotype' and to evaluate the associations between the biomarkers levels and the severity of disease by spirometric measurements. Methods A total of 84 COPD patients and 49 healthy controls were enrolled in our study. ELISA were utilised to detect the FKN, MMP-12 and NE in serum from all subjects. Results FKN (p<0.001), NE (p=0.039) and MMP-12 (p<0.001) in serum of COPD patients showed higher levels than that of healthy control subjects. Serum FKN (p<0.001), MMP-12 (p<0.001) and NE (p=0.043) levels were significantly higher in severe and very severe COPD patients than that in mild and moderate COPD patients. Circulating FKN, MMP-12 and NE expression levels were significantly elevated (p<0.001) in COPD smokers compared with COPD non-smokers. The smoke pack years were negatively correlated with FEV1%pred (r=-0.5036), FEV1/FVC ratio (r=-0.2847) (FEV, forced expiratory volume; FVC, forced vital capacity). Similarly, we observed a strong positive correlation between the smoke pack years and serum levels of FKN (r=0.4971), MMP-12 (r=0.4315) and NE (r=0.2754). FEV1%pred was strongly negatively correlated with cytokine levels of FKN (r=-0.4367), MMP-12 (r=-0.3295) and NE (r=-0.2684). Likewise, FEV1/FVC ratio was negatively correlated with mediators of inflammation levels of FKN (r=-0.3867), MMP-12 (r=-0.2941) and NE (r=-0.2153). Conclusion Serum FKN, MMP-12 and NE concentrations in COPD patients are directly associated with the severity of COPD with 'exacerbator with emphysema phenotype'. This finding suggests that FKN, MMP-12 and NE might play an important role in the pathophysiology of COPD.