Environmental exposure to carbon nanotubes results in systemic distribution via the circulatory system: hepatotoxicity and central nervous system involvement.

Carbon nanotubes (CNTs) are among the most promising nanomaterials and their interesting properties are now exploited in many fields of technology and biomedical applications. However, the rapid growth of CNT employment raises concerns about the potential risks and toxicities to public health, environment and workers associated with the manufacture and use of these new materials. Here we investigate the main routes of entry following environmental exposure to CNTs, their localization and possible role in inducing inflammation and specific pathologies, using a novel rodent model. Following environmental exposure, we observed that CNTs rapidly accumulate in the lungs and brain, later reaching other organs including the liver, where steatosis was found after chronic exposure to CNTs. Since SWCNTs are considered for potential medical applications ad their toxicity is similar to that of MWCNTs, we further examined the effects of chronic intravenous SWCNT administration, which resulted in a chronic inflammatory condition particularly evident in the liver that was associated with a choleostasis-like syndrome. Our data suggest that after environmental exposure, CNTs can rapidly enter and diffuse in the organism via the blood stream, in addition to the lungs, which appear to have a capacity to clear CNTs, the liver may be the major site of CNT induced damage, where long term accumulation results in inflammation, steatosis and a choleostasis-like condition.