Exposure to Nano-Sized Particles and the Emergence of Contemporary Diseases with a Focus on Epigenetics

Mankind has been exposed to airborne nano-sized particles for eons, yet mechanization and industrialization of societies has increased the overall aerosol pollution load to which humans are exposed to. Nano-aerosols with a diameter below 1 μm, can be incorporated via any biological surface structure and in particular when the area available is large enough – as is the case with the skin (approx. 1.5-2 m2), the digestive tract (intestinal villi, approx. 200 m2) or the respiratory tract (alveolar surface area reaching approx. 140 m2).(Raab et al, 2010) Since aerosolised particles are readily inhaled rather than ingested, the lungs represent an ideal gateway with high penetration efficiency rates. From a toxicological rather than from a therapeutic point of view, a deposited xenobiotic particle first interacts with biological tissues on a cellular level. From there it is readily translocated into the cell to interfere with metabolic pathways, eventually inducing inflammatory cellular responses. At an organismic level along with long-term exposure these particles become redistributed via the lymphatic or the blood circulatory system to reach sensitive organs or tissues, such as the central nervous system, bone marrow, lymph nodes, spleen, heart, etc.(Oberdörster et al. 2005a) At this level, persistent particle exposure may trigger chronic diseases or when already present, modulate the severity of its course.