Thyme extract increases mucociliary-beating frequency in primary cell lines from chronic obstructive pulmonary disease patients

Abstract

Chronic obstructive pulmonary disease (COPD) is a respiratory disorder characterized by a progressive and irreversible airflow limitation. COPD is associated to a chronic inflammatory response with infiltration of inflammatory cells in the surface epithelium of large airways and abnormalities in structure and functions of cilia. Thyme (Thymus vulgaris L.) is a traditional medicinal plant of the Mediterranean area used to treat respiratory disorders. We previously evidenced that thyme extract reduce IL-1beta and IL-8, by downregulating the activated NF-κB levels, suggesting its potential therapeutically use in COPD. Cilia beating frequency (CBF) is dramatically impaired in COPD and different pharmacological agents can modulate cilia function. Herein we evaluated the effect of a commercial thyme extract in modulating CBF by measuring its activity in stimulating cAMP, Ca²⁺ levels and CBF in a MucilAir 3D human COPD airway epithelia reconstituted in vitro system using salmeterol, YM976, isoproterenol and GSK1016790 A as positive controls. Results showed that thyme extract increased cAMP levels starting from 12 h post-treatment, decreased extracellular Ca²⁺ levels and increased the CBF in airway epithelia from COPD donors. Overall, this work demonstrated that thyme extract is effective in stimulating CBF by inducing an increase of cAMP and Ca²⁺ levels, thus supporting its therapeutical use in the treatment of COPD.

Keywords: COPD; Calcium; Cilia beating; TRPV4; Thyme extract; cAMP.