Respiratory irritants cause reversible up-regulation of pro-inflammatory cytokines on human nasal mucosa reconstituted in vitro

Faten Hussein¹, Bernadett Boda¹, Ludovic Wiszniewski¹, Song Huang¹ & Samuel Constant¹

¹Epithelix Sàrl, 18 chemin des aulx, 1228 Plan-les-Ouates, Geneva, Switzerland

Summary

Respiratory irritants are considered as substances of higher risk, at the same level as Carcinogens, Mutagens and toxic chemicals for Reproduction. However, until now there is no validated in vitro cell model for identifying the respiratory chemical irritants. The aim of this study is to develop an in vitro cellular assay for identification of respiratory chemical irritants based on in vitro human 3D nasal airway epithelium (MucilAir^™). Epithelia were reconstituted with primary human nasal cell polled from 14 donors. MucilAir^™ is not only morphologically and functionally differentiated; but it can also remain at a homeostatic state for more than one year, allowing repeated dose and long term toxicity testing.

11 chemical compounds belonging to 3 classes (irritants ”H335”, highly toxic “H330”,  and  non-toxic chemicals through inhalation) were tested. The cytotoxic effects of these chemicals were assessed by several endpoints: TEER measurement, cilia beating monitoring, LDH release, morphological observation, etc…  Pro-inflammatory cytokines, IL-8 and IL-6 were used as biomarkers for discriminating these molecules. Interestingly, at sub-toxic doses, only the respiratory irritants upregulated reversibly the secretion of IL-8 and IL-6 upon acute challenge.

Taken together, MucilAir^™ seems to be a promising in vitro model for discriminating the respiratory irritants from highly or nontoxic compounds.