Effect of Cr(VI) and Ni(II) metal ions on human adipose derived stem cells

Environmental exposure of Cr(VI) and Ni(II) due to rapid industrialization causes adverse effects in living tissues. Small quantities of these ions also find their way into tissues when metal alloys are used as implants. Even though considerable research has been done on the effects due to their exposure in animal cells, there are only very few reports on how they can affect stem cells which have been shown to be found in adult tissues as well, albeit in small quantities. Hence this study was aimed at understanding how Cr(VI) and Ni(II) affect human adipose derived stem cells (hADSCs) in a cell culture environment. Our results indicate that both ions induce apoptosis in a concentration and time dependent manner with loss of mitochondrial membrane potential (MMP) and corresponding increase in caspase-3 activity. With regard to Ni(II), apoptosis seems to occur only in a small percentage of cells while necrosis is predominant. It can be inferred that the long term exposure of these metals may cause adverse effects in stem cell proliferation and differentiation.