Using iron sucrose-labeled adipose-derived mesenchymal stem cells in 1.5 and 3 T MRI tracking: An in vitro study

OBJECTIVES: The objective of this study was to investigate iron sucrose labeling in mesenchymal stem cell (MSCs) tracking. BACKGROUND: Adipose-derived mesenchymal stem cell-based therapy is a promising strategy for promoting musculoskeletal repair. METHODS: Iron sucrose-labeled adipose-derived mesenchymal stem cells (IS-labeled ASCs) were tracked using T2-and T2∗-weighted sequences by 1.5 and 3 T MRI in an in vitro model. ASCs were isolated from cosmetic liposuction specimens. ASCs from passages 4–6 were labeled with iron sucrose (Venofer®) which was added to the cell culture medium. Pre- and post-iron sucrose labeled ASCs were evaluated for cell surface immunophenotypes. Cell viability as well as chondrogenic, adipogenic and osteogenic differentiation of IS-labeled-ASCs were evaluated. The IS-labeled ASCs were titrated into microtubes at 1 × 10(3), 1 × 10(4), 1 × 10(5) and 1 × 10(6) cells/ml/microtube and their intensities were determined by 1.5 and 3T MRI using T2-and T2∗-weighted sequences. RESULTS: The expression markers of IS-labeled ASCs from flow cytometry were equivalent to control. The mean cell viability was 97.73 ± 2.06%. Cell differentiations of IS-labeled ASCs were confirmed in each lineage using specific staining solutions. T2∗-weighted sequences (T2∗) were able to detect iron sucrose labeled-ASCs at a minimum of 1 × 10(5) cells/ml/microtube using 1.5 and 3T MRI, but the detection sensitivity was lower with T2-weighted sequences (T2). CONCLUSIONS: Iron sucrose incubation is a safe alternative method for ASCs labeling and tracking using MRI following treatment. Clinicians and researchers should be able to visualize the location of ASCs engraftment without secondary surgical investigation involving tissue sampling.