Alterations in Plasma miR-21, miR-590, miR-192 and miR-215 in Patients with Idiopathic Pulmonary Fibrosis and Their Clinical Importance

Abstract Background: It is well-established that microRNAs (miRNAs) have regulatory roles in the fibrotic processes of various tissues. Studies revealed that some miRNAs play a pivotal role in the development of idiopathic pulmonary fibrosis (IPF). Methods: In this single-center, cross-sectional study, the plasma levels of miR-21, miR-590, miR-192, and miR-215 in IPF (n=88) and the control (n=20) group were investigated using real-time PCR. The pulmonary function tests and the plasma sampling of participants were carried out simultaneously. Patients were grouped according to age, forced vital capacity, diffusing capacity for carbon monoxide (DLCO), and the Gender-Age-pulmonary Physiology (GAP) score. The expression levels of the target miRNAs between these clinical subgroups were compared. Results: The IPF and control groups were similar in terms of gender and age. The mean plasma miR-21 and miR-590 levels in IPF were significantly higher than in the control (p<0.0001, p<0.0001, respectively). There was no significant difference in miR-192 and miR-215 levels between the groups. While miR-21 and miR-590 correlated positively with age (p=0.041, p=0.007, respectively), miR-192 and miR-215 displayed a negative correlation with age (p=0.0002, p<0.0001, respectively). MiR-192 and miR-215 increased as the GAP score decreased and miR-192 level in patients with honeycombing was significantly lower than in those without honeycombing (p=0.003). Conclusions: Our results suggest that higher plasma levels of miR-21 and miR-590 were related to the presence of IPF. While all target miRNAs correlated with age, the miR-21 and miR-590 were associated with DLCO, and miR-192 and miR-215 were associated with GAP score and honeycombing.