Karl Saldanha1, Ryan Doan1,2, Sharmila Majumdar1
1Department of Radiology, UCSF, San Francisco, CA, USA; 2Cleveland Clinic Lerner College of Medicine, Cleveland, OH, USA
Mesenchymal stem cells (MSCs), have demonstrated differentiation into chondrocytes, with applications to treating cartilage defects or osteoarthritis. Iron oxide labeling of MSCs before implantation may enable longitudinal non-invasive in vivo assessment of cells via magnetic resonance imaging (MRI). This study examined MSC labeling with micrometer-sized iron oxides (MPIOs) and the effect of labeling on chondrogenesis. Results indicate cellular uptake of MPIOs, with associated signal loss on MR images at clinically relevant field strengths. While labeling does not inhibit chondrogenesis, the presence of extracellular iron may have implications for the effectiveness of using MRI to monitor stem cell-based cartilage regeneration.