Occupational exposure to asbestos is universally associated with several lung injuries, including respiratory diseases, asbestosis, mesothelioma, and, owing to others co-factors, lung cancer. Pleural malignant mesothelioma, in particular, is highly deadly, the 5-year survival rate being of 5% only (1 over 20). In addition, due to weathering of asbestos-reinforced cement products, asbestos contamination is also becoming of concern for the general population, in particular in urban areas. Asbestos can enter in living organisms by inhalation and, also due to its high bio-persistence, can manifest its toxicity after 20 to 40 years. For these reason asbestos remains a current major worldwide health threat, although, starting from the 1990s, it was banned in most countries and it is almost abolished today, with a few relevant exceptions (Russia, China, Canada, and Brazil). In fact, it is foreseen that the peak of mesothelioma cases in the world will be reached within 2020. At a world scale, the US National Institute of Health (NIH) estimated that 11 million people were exposed to asbestos between 1940 and 1978. These figures push to the conclusion that extensive research on asbestos interaction with host organism can have an impact on a large number of people in Europe and worldwide.
Once penetrated into the lungs of exposed people, asbestos fibers irritate the tissue, causing minerals and proteins to cluster around the foreign fibers in a process known as biomineralization. The resulting clusters are referred to as asbestos bodies. A satisfactory knowledge of the elemental composition and fine structure of the asbestos bodies, and a solid model of their formation mechanism is still lacking, preventing the formulation of the carcinogenic mechanism. The aim of this research project was therefore to obtain a solid morphological, structural, elemental, and chemical characterization of the asbestos bodies in human lung tissue, and to achieve this aim, the project is organized in the following tasks:
- Revealing the morphology and elemental composition of the asbestos bodies with unprecedented level of detail and sensitivity;
- Providing reliable and spatially resolved elemental quantification;
- Detecting possible structural and chemical modifications occurring to the fibers after prolonged stay in the lungs.
These objectives were achieved by combining advanced synchrotron radiation micro-probe tools with electron microscopy techniques and laboratory analyses and the acquired knowledge allowed to propose a model for the formation mechanims of the asbestos bodies.
