Reduced neutrophil elastase inhibitor elafin and elevated transforming growth factor-β1 are linked to inflammatory response in sputum of cystic fibrosis patients with Pseudomonas aeruginosa

Jan C Thomassen; Tobias Trojan; Maxine Walz; Christina Vohlen; Gregor Fink; Ernst Rietschel; Miguel A Alejandre Alcazar; Silke van Koningsbruggen-Rietschel

doi:10.1183/23120541.00636-2020

Reduced neutrophil elastase inhibitor elafin and elevated transforming growth factor-β₁ are linked to inflammatory response in sputum of cystic fibrosis patients with Pseudomonas aeruginosa

ERJ Open Res. 2021 Jul 19;7(3):00636-2020. doi: 10.1183/23120541.00636-2020. eCollection 2021 Jul.

Authors

Affiliations

¹ CF Center, Children's Hospital, Faculty of Medicine, University of Cologne, Cologne, Germany.
² Translational Experimental Pediatrics - Experimental Pulmonology, Children's Hospital, Faculty of Medicine, University of Cologne, Cologne, Germany.
³ Center of Molecular Medicine Cologne, Faculty of Medicine, University of Cologne, Cologne, Germany.

Abstract

Research question: Pulmonary disease progression in patients with cystic fibrosis (CF) is characterised by inflammation and fibrosis and aggravated by Pseudomonas aeruginosa (Pa). We investigated the impact of Pa specifically on: 1) protease/antiprotease balance; 2) inflammation; and 3) the link of both parameters to clinical parameters of CF patients.

Methods: Transforming growth factor-β₁ (TGF-β₁), interleukin (IL)-1β, IL-8, neutrophil elastase (NE) and elastase inhibitor elafin were measured (ELISA assays), and gene expression of the NF-κB pathway was assessed (reverse transcriptase PCR) in the sputum of 60 CF patients with a minimum age of 5 years. Spirometry was assessed according to American Thoracic Society guidelines.

Results: Our results demonstrated the following: 1) NE was markedly increased in Pa-positive sputum, whereas elafin was significantly decreased; 2) increased IL-1β/IL-8 levels were associated with both Pa infection and reduced forced expiratory volume in 1 s, and sputum TGF-β₁ was elevated in Pa-infected CF patients and linked to an impaired lung function; and 3) gene expression of NF-κB signalling components was increased in sputum of Pa-infected patients, and these findings were positively correlated with IL-8.

Conclusion: Our study links Pa infection to an imbalance of NE and NE inhibitor elafin and increased inflammatory mediators. Moreover, our data demonstrate an association between high TGF-β₁ sputum levels and a progress in chronic lung inflammation and pulmonary fibrosis in CF. Controlling the excessive airway inflammation by inhibition of NE and TGF-β₁ might be promising therapeutic strategies in future CF therapy and a possible complement to cystic fibrosis transmembrane conductance regulator (CFTR) modulators.