Correlation of severity of chronic obstructive pulmonary disease with potential biomarkers

Abstract

BackgroundChronic obstructive pulmonary disease (COPD) is a non-specific inflammation, which involves the airways, lung parenchyma and pulmonary vessels. The inflammation causes the activation of inflammatory cells and the release of various inflammatory mediators such as interleukin-1 beta, interleukin-6 and tumor necrosis factor alpha (TNF-a). The present study was designed to assess the serum cytokines [Interleukin-1β (IL-1β), Interleukin-6 (IL-6), Tumor necrosis factor-α (TNF-α)] levels in chronic obstructive pulmonary disease (COPD) patients and they were correlated with severity of disease by spirometric measurements. Materials and methodsA total of 384 COPD patients and 50 healthy controls were enrolled in this study. The COPD patients were divided according to gold stages ie: mild, moderate, severe and very severe. 5 ml of venous blood samples were taken from all participants and it was collected in a test tube containing anticoagulant and then centrifuged at 3000 rpm for 10 min. Serum was separated and used to measure the amount of TNF-alpha, il-1beta, and IL-6. Spirometry was performed according to the criteria set by the Gold 2012 ResultsTnf-α (pg/ml), IL-6 (pg/ml), IL-1β (pg/ml) serum levels in COPD patients and healthy controls subjects were measured. Tnf-α and IL-6 serum levels were significantly (<0.001) higher in COPD patients compared to healthy control subjects. Likewise, IL-1 beta levels were also significantly (p-value = 0.022) higher in COPD patients compared to healthy control subjects. The distribution of Tnf-α, IL-6, IL-1β (pg/ml) serum levels in COPD patients in relation to GOLD grading. There was a significant (p < 0.001) difference in the level of TNF-α, IL-6 and IL-1β (pg/ml) among the severity of COPD. The posthoc analysis revealed that the TNF-α was significantly (p < 0.05) higher among the than mild, moderate, severe and very severe COPD patients. A similar observation was also found for IL-6. However, IL-6 was significantly (p < 0.05) higher among mild, moderate, severe and very severe COPD patients. There was significant (p = < 0.0001) difference in the level of IL-1β in the different severity of COPD. The posthoc comparison test showed that IL-1β levels were significantly (p < 0.05) higher among the mild, moderate, severe and very severe COPD patients. ConclusionThe present study signifies that the levels of TNF-α, IL-1β, and IL-6 are directly proportional to the post-bronchodilator FEV1 percentage. Results provide population-based evidence that COPD is independently associated with low-grade systemic inflammation, with a different inflammatory pattern than that observed in healthy subjects. Overall, these results identify a novel systemic inflammatory COPD phenotype that may be the target of specific research and treatment.