International Journal of COPD (Jul 2019)
Overexpression of chitotriosidase and YKL-40 in peripheral blood and sputum of healthy smokers and patients with chronic obstructive pulmonary disease
Abstract
Sebastian Majewski,1 Damian Tworek,2 Karolina Szewczyk,1 Justyna Kiszałkiewicz,3 Zofia Kurmanowska,1 Ewa Brzeziańska-Lasota,3 Hanna Jerczyńska,4 Adam Antczak,2 Wojciech Jerzy Piotrowski,1 Paweł Górski11Department of Pneumology and Allergy, Medical University of Lodz, Lodz, Poland; 2Department of General and Oncological Pulmonology, Medical University of Lodz, Lodz, Poland; 3Department of Molecular Bases of Medicine, Medical University of Lodz, Lodz, Poland; 4Central Scientific Laboratory (CoreLab), Medical University of Lodz, Lodz, PolandBackground: Despite the absence of endogenous chitin in humans, chitinases are present in the serum of healthy subjects and their levels are increased in a variety of chronic inflammatory conditions. It has been shown that chitotriosidase and structurally related chitinase-like protein-YKL-40 contribute to the pathogenesis of COPD. However, details regarding the relation of their systemic and local airways levels remain unknown.Objectives: To examine peripheral blood and sputum chitotriosidase and YKL-40 expression in smokers and patients with COPD.Methods: Forty patients with COPD, 20 healthy smokers and 10 healthy never-smokers were studied. Serum and induced sputum chitotriosidase protein and activity levels, YKL-40 concentrations, and their gene expression in sputum cells and peripheral blood mononuclear cells (PBMC) were evaluated.Results: Both chitotriosidase protein levels and activity were higher in sputum obtained from COPD subjects compared to healthy never-smokers (P<0.05 and P<0.01, respectively). A similar pattern was observed for PBMC chitotriosidase mRNA expression (P<0.001). YKL-40 serum concentrations were elevated in healthy smokers and COPD subjects compared to healthy never-smokers (P<0.001 and P<0.01, respectively). In sputum, YKL-40 levels were increased in COPD compared to healthy never-smokers (P<0.01). PBMC YKL-40 mRNA expression was increased in COPD and healthy smokers compared to healthy never-smokers (P<0.0001). No associations were found between chitotriosidase or YKL-40 peripheral blood levels and sputum levels.Conclusions: Our results demonstrate that chitotriosidase and YKL-40 are overexpressed in peripheral blood and airways in both healthy smokers and COPD subjects which may indicate smoking-related activation of macrophages, neutrophils, and epithelial cells.Keywords: chitotriosidase, CHIT1, YKL-40, chitinase, chitin-like protein, COPD