Manganese‐guided cellular MRI of human embryonic stem cell and human bone marrow stromal cell viability

This study investigated the ability of MnCl2 as a cellular MRI contrast agent to determine the in vitro viability of human embryonic stem cells (hESC) and human bone marrow stromal cells (hBMSC). Basic MRI parameters including T1 and T2 values of MnCl2-labeled hESC and hBMSC were measured and viability signal of manganese (Mn2+)-labeled cells was validated. Furthermore, the biological activity of Ca2+-channels was modulated utilizing both Ca2+-channel agonist and antagonist to evaluate concomitant signal changes. Metabolic effects of MnCl2-labeling were also assessed using assays for cell viability, proliferation, and apoptosis. Finally, in vivo Mn2+-guided MRI of the transplanted hESC was successfully achieved and validated by bioluminescence imaging. Magn Reson Med, 2009. © 2009 Wiley-Liss, Inc.