Figure 2.

Molecular and cellular mechanisms linked to toxic effects of environmental pollutants on hematopoiesis. (A) Benzene (BZ) is metabolized by CYP2E1 in liver and lung generating hydroquinone (HQ) and catechol (Cat), which are then transformed into benzoquinone (BQ). These metabolites exert myelotoxic actions upon several hematopoietic progenitors mainly by increasing levels of reactive oxygen species (ROSs), leading to oxidative DNA damage. (B) Nanoparticles and particulate matter induce generation of ROSs and secretion of inflammatory cytokines that affect the behavior of several hematopoietic cell lineages. (C) Dioxins and PCBs bind to and activate the aryl hydrocarbon receptor (AhR) in mucosal tissues, modulating the hematopoietic stem cell (HSC) pool and triggering both immunosuppressive effects and myelodysplastic and malignant abnormalities. (D) Heavy metals can enter the body via several contact routes, their toxic effects being responsible for impairing inflammatory responses and triggering leukemias and anemias.