Peripheral Blood Expressions of MicroRNA-146a and MicroRNA-218 in Chronic Obstructive Pulmonary Disease with/without Cigarette Smoke Exposure

Altered expression and dysregulation of microRNAs (miRNAs) have been reported in different samples of chronic obstructive pulmonary disease (COPD) patients. The present study attempted to evaluate the peripheral expressions of miR-146a and miR-218 in COPD patients and sex-matched healthy controls with/without cigarette smoke exposure (CSE). In this case-control study, blood samples were collected from 60 COPD patients (30 with CSE and 30 non-CSE in each group) and 60 healthy controls. Peripheral expressions of miRNA-146a and miR-218a were measured using qRT-PCR and results were compared between cases and controls as well as within the subgroups of patients. We found significantly decreased expressions for both miRNAs in the patients compared to healthy controls. Remarkable underexpression of miRNA-146a and miRNA-218 were found in the CSE and non-CSE patients compared to non-CSE healthy controls and even in the CSE versus non-CSE controls. Both groups of patients showed underexpression of two miRNAs in comparison with CSE healthy controls and interestingly, similar decrements were observed in the CSE versus non-CSE patients. Also, ROC curve analysis revealed the significantly diagnostic powers for both miRNAs in discrimination of patients from healthy individuals and CSE-COPD from non-CSE COPD patients. The underexpression of miR-146a and miR-218 in COPD patients and relation to CSE can be indicative of CSE-induced changes in miRNA expression profile and potential for these biomarkers in COPD risk assessment, particularly in those patients with CSE.