INFLAMMATORY AND CARCINOGENIC POTENTIAL OF MINERAL FIBRES ASSESSED THROUGH A PHYSIOLOGICALLY RELEVANT 3D IN VITRO MODEL OF HUMAN ALVEOLAR TISSUE

The severe health problems derived from the prolonged inhalation of particulate matter and mineral fibres, such as pulmonary fibrosis, asbestosis, silicosis, lung cancer and pleural mesothelioma, to cite a few, are a well-known issue for several classes of exposed workers even in the modern society[1]. Furthermore, given the considerable number of chemicals and new materials potentially producing respirable particulates continuously placed on the market, the setup of new high throughput approaches to evaluate the effects of multiple inhaled substances, could overcome many issues related to the massive use of expensive, poorly relatable, and ethically concerning animal models. In this context, a very good alternative would be the development of physiologically relevant 3D in vitro models of the human alveolar tissue for the prediction of the toxicity/carcinogenicity of inhaled substances/particulates. We propose the setup of two 3D models of the human pulmonary tissue in vitro, either mimicking the thinnest, either the thickest part of the alveoli, implemented by the addition of the human immune component to be able to fully recapitulate in vitro the inflammatory process caused by inhalation of hazardous agents. The thinner model is produced by the stratification of human alveolar and endothelial cells separated by an electrospun PCL-Gel membrane mimicking the alveolar basement membrane, while the thicker model also contains the collagen-embedded human fibroblast component stratified between the alveolar epithelium and the basement membrane. The THP-1 derived human macrophages are then added to the two 3D systems and the toxicity/carcinogenicity of chrysotile and crocidolite mineral fibers with asbestiform behavior is then assessed by comparison with a non toxic wollastonite mineral. The evaluation of cytototoxicity, genotoxicity and inflammation is the performed with the attempt to identify specific markers useful to develop standardized tests to assess the human pulmonary toxicity of hazardous agents.