Benzene exposure--an experimental machinery for induction of myelodysplastic syndrome: stem cell and stem cell niche analysis in the bone marrow.

Human epidemiologic studies of highly exposed occupational cohorts have demonstrated that inhalation/exposure to benzene can cause several blood disorders, like non-lymphocytic leukemia, pre leukemic stage, aplastic anemia, and other related syndromes collectively considered as bone marrow failure syndromes. Like many other agents [e.g. chemotherapeutics etc] benzene selects the bone marrow as an important target but the exact location and the mechanism of damage is yet unexplored. The present study aimed at delineating benzene induced myelodysplasia and related disorders in an experimental mouse model with a view to assessing the clinical hazards in human at a comparable event. The observations made so far documented some quantitative and qualitative changes in the bone marrow population, especially involving the hematopoietic stem cells and related microenvironment, their immune responsiveness and survival fate of the cells at that particular event. The observations furnished that benzene following occupational exposure can be hazardous by way of HSC mediated dysfunction and, the microenvironmental studies conducted in some details indicated that the damage may be in the bone marrow stem cell niche. Furthermore, some data collected showed an increased death rate of bone marrow cells and associated abnormalities in receptor expression of adhesion molecules and related growth factors. Culminating the above data the study reveals that Benzene may cause target damage in the bone marrow stem cell niche [BM SC niche] both structurally and functionally, with the resultant disease expression as in MDS.