A new formulation of n-acetylcisteine, carnitine, curcumin and B2 vitamin exerts anti-oxidant and anti-inflammatory effects in a primary 3D bronchial epithelial model exposed to cigarette smoke extracts

Cigarette smoke, the main risk factor for Chronic Obstructive Pulmonary Disease (COPD), is a potent pro-oxidant stimulus. Increased oxidative stress within the airways is associated to epithelial damage and amplification of inflammatory responses that in turn contribute to disease progression. The aim of this in vitro study was to identify whether a new formulation of n-acetylcisteine, carnitine, curcumin and B2 vitamin could counteract oxidative stress and downstream pro-inflammatory events promoted by cigarette smoke extract (CSE) exposure in 3D primary bronchial epithelial cells (PBEC) cultured at the air-liquid interface (ALI) and differentiated to form a pseudostratified epithelium. In 3D cultures exposed to CSE with or without 2 hours pre-incubation with the new formulation, we evaluated: a) cell viability by MTS; b) intracellular mitochondrial ROS production by flow cytometry; c) IL-8 and IL-6 protein release by ELISA on supernatants collected at apical and basal sides. CSE increased mitochondrial ROS production, basal and apical release of IL-8 and basal release of IL-6. The new formulation did not alter cell viability and was effective preventing the increase of mitochondrial ROS and of the basal and apical increase of IL-8 or of basal IL-6. NAC did not counteract the CSE effects on mitochondrial ROS production and IL-6 release. In conclusion, the tested formulation, exerting anti-oxidant and anti-inflammatory effects, can preserve airway epithelial homeostasis.Future studies are needed to validate its role as add-on treatment in COPD patients.