Mesenchymal stem cell tracking in the intervertebral disc

Table 1 Review of stem cell tracking in the intervertebral disc in animal models reported in the literature

Ref.	Animal model	Cell type	Label	Imaging	Results
Saldanha et al[105], 2008	Rat tail (ex vivo)	Human MSCs (Loaded in fibrin gel-Tisseel)	FE-Pro (Feridex and Proatmine Sulphate)	3T MRI	No significant effect of labeling on MSC viability Hypointensity (signal loss) seen in discs injected with labeled cell
Prologo et al[62], 2012	Porcine n = 4	Human MSCs	Iodine-124 2’fluoro-2’-deoxy-1b-D-arabinofuranosyl-5-iodouracil	PET/CT	Inaccurate delivery in 1 animal Three animals showed persistence and containment of labeled cells 3 d following injection
Barczewska et al[106], 2013	Porcine n = 1 (ex vivo) n = 3 (in vivo)	Porcine MSCs	Molday ION USPION	3T MRI	Ex vivo-Injected labeled cells clearly visualized In vivo-hypointense regions identified immediately following injection of labeled cells. Histopathology performed 2 wk later confirmed the presence of MSCs in the disc

MSC: Mesenchymal stem cell; MRI: Magnetic resonance imaging; USPION: Ultrasmall superparagmetic iron oxide nanoparticle; PET/CT: Positron emission tomography/computed tomography.