Cancers and other diseases caused by asbestos and has led to the ‘fibre paradigm’ that in essence suggests that biopersistent, fibre like, materials have a potential for asbestos-like negative health effects. The overwhelmingly most common type of fiber-like nanomaterials are the carbon nanotubes (CNTs) of which there are numerous types. As predicted by the paradigm some CNTs have been shown to elicit tumour formation in animal models. Because of the very broad variety of CNTs it is imperative to understand which of these will have asbestos like effects. There are also unanswered questions about the carcinogenicity of CNTs that are not asbestos-like.Methods
The presentation will discuss asbestos related carcinogenicity and evaluate the differences and similarities to the current understanding of CNT related carcinogenesis. Special attention will be paid to in vivo studies and histology. In addition to discussing published literature some unpublished results will also be presented.Results
The early phases of asbestos induced effects in vivo include activation of inflammatory cascades and the production of reactive oxygen species. These effects are not that specific for asbestos and can be found in association with silica exposures and other exposures, including nanomaterials. A somewhat specific feature of asbestos exposure is a in vivo is eosinophilia associated with a Th2 type of immunological response. Interestingly this type of reaction can be seen in some types of CNTs with physical properties reminiscent of asbestos.Discussion
Some CNTs do have physicochemical properties and an in vivo inflammatory response similar to that of asbestos. The potential for carcinogenicity of CNTs without these asbestos-like features is rather poorly investigated. Additional studies with traditional animal models for carcinogenicity are needed to provide a foundation for other approaches to determine carcinogenic potential.