After three passages of MSCs, the patients received a total of 250?00¡Á106 cells, of which only 50 % of the cells were labeled. Specific activities of 0.21?.67 MBq/106 cells were maintained for the injected labeled MSCs. Planar whole-body acquisitions (anterior/posterior projections) were acquired immediately following infusion as well as at 2 h, 4 h, 6 h, 24 h, 48 h, 7th and 10th days after cell infusion.
After intravenous infusion, the radioactivity was first observed to accumulate in the lungs. During the following hours to days, the radioactivity gradually increased in the liver and spleen, with spleen uptake exceeding that in the liver in all patients. Region-of-interest analysis showed that the percentage of cells homing to the liver (following decay and background corrections and geometric mean calculation) increased from 0.0 % -2.8 % at immediately post-infusion images to 13.0?7.4 % in 10th-day post-infusion. Similarly, the residual activities in the spleen increased from 2.0 % -10.2 % at immediately post-infusion images to 30.1 % -42.2 % in 10th-day post-infusion. During the same period, the residual activities in the lungs decreased from 27.0?3.5 % to 2.0?.4 % .
The infusion of MSCs labeled with 111In-oxine through a peripheral vein is safe in cirrhosis. Cell labeling with 111In-oxine is a suitable method for tracking MSC distribution after infusion.