Metal toxicity represents a significant public health concern and contributes toÂ many toxic metal-exposure related diseases. In particular, toxic metals promote theÂ oxidative stress in stem cells and endothelial progenitor cells (EPCs). EPCs that areÂ presented in peripheral blood function to replenish aging damaged endothelial cellsÂ and play important role in the maintenance of vasculature and neovascularization.Â Given the links between oxidative injury, endothelial cell dysfunction and vascularÂ disease, we focused our investigation on the response of CD34-positive cells toÂ chelation by DMSA.Â
In addition, we compared the effectiveness of DMSA and EDTA in the chelation ofÂ toxic metals and the excretion of essential metals.The data were compared for 160 subjects after oral DMSA (500mg) chelation and 250Â subjects after intravenous EDTA (1g-3g) chelation.Â Our in vitro experiments were designed to compare the intrinsic toxicity of twoÂ antidotes and their effectiveness in lead chelation.Â One of the important results of our study shows that the removal of toxic metalsÂ improves the number of stem/progenitor cells in circulation. After a series of fiveÂ DMSA treatments, the number of CD34+ cells in circulation was increased on 50%-160% (p<0.05).Â
Our in vitro experiments demonstrated that toxic metals (lead and mercury) inhibitÂ mesenchymal stem cell metabolism and proliferation, and that stem cells are moreÂ sensitive to these metals than differentiated cells.Â In comparison with EDTA, DMSA was more effective in the extraction of lead, butÂ treatment by this antidote resulted in a very high excretion of copper (55 folds).Â Clearance of essential metals during chelation by 1g-3g of EDTA was increased overÂ twenty-fold for zinc and manganese.
In summary, we suggest that chelation therapy shows promise in repairing metalÂ toxicity damage and restoring circulating stem cells.
Nina Mikirova , Joseph Casciari , Ronald Hunninghake