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

Abstract This study investigated the ability of MnCl 2 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 T 1 and T 2 values of MnCl 2 ‐labeled hESC and hBMSC were measured and viability signal of manganese (Mn 2+ )‐labeled cells was validated. Furthermore, the biological activity of Ca 2+ ‐channels was modulated utilizing both Ca 2+ ‐channel agonist and antagonist to evaluate concomitant signal changes. Metabolic effects of MnCl 2 ‐labeling were also assessed using assays for cell viability, proliferation, and apoptosis. Finally, in vivo Mn 2+ ‐guided MRI of the transplanted hESC was successfully achieved and validated by bioluminescence imaging. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.