Differential protein folding and chemical changes in lung tissues exposed to asbestos or particulates (original) (raw)

Environmental and occupational inhalants may induce a large number of pulmonary diseases, with asbestos exposure being the most risky. The mechanisms are clearly related to chemical composition and physical and surface properties of materials. A combination of X-ray fluorescence (μXRF) and Fourier Transform InfraRed (μFTIR) microscopy was used to chemically characterize and compare asbestos bodies versus environmental particulates (anthracosis) in lung tissues from asbestos exposed and control patients. μXRF analyses revealed heterogeneously aggregated particles in the anthracotic structures, containing mainly Si, K, Al and Fe. Both asbestos and particulates alter lung iron homeostasis, with a more marked effect in asbestos exposure. μFTIR analyses revealed abundant proteins on asbestos bodies but not on anthracotic particles. Most importantly, the analyses demonstrated that the asbestos coating proteins contain high levels of β-sheet structures. The occurrence of conformational changes in the proteic component of the asbestos coating provides new insights into long-term asbestos effects. A large number of pulmonary diseases are induced by the effects of nano-and micro-particulates in the inhalants, in particular cigarette smoke, environmental pollution or as a consequence of occupational exposure. With regard to occupational exposure diseases, an improvement has been noted after the introduction of severe industrial hygiene regulations in developed countries, that led to a decline in the incidence and prevalence of pneumoconiosis. However, asbestos-related diseases, particularly mesothelioma, are still a major public health problem, due to the extremely long latency period. Pneumoconiosis is a group of occupational lung diseases caused by inhaled dust particles and fibres, which causes inflammation of the pulmonary parenchyma leading to fibrosis. The most common types of pneumoconiosis include silicosis, coal workers' pneumoconiosis and asbestosis. Asbestosis is a chronic inflammation process caused by the inhalation of excessive amounts of asbestos fibres. Pathologically, it is characterized by both a particular pattern of interstitial pulmonary fibrosis and the presence of asbestos bodies, which are the hallmarks of asbestos exposure. The pathogenic factors involved in asbestosis and other asbestos-related diseases are extremely complex. Moreover, also in undoubted cases of occupational