Questions under study: Many studies have demonstrated that mesenchymal stem cells (MSCs) contribute to the recovery of acute renal failure (ARF). The purpose of the present study was to evaluate tracking of MSCs intravascularly administered in a rat model of ARF for cellular therapy using a 1.5 T MRI system.
Methods: Fe2O3-PLL nanoparticle-labelled and unlabelled MSCs were injected into the abdominal aortas by transcatheterisation of 20 ARF rats, whose renal failure was induced by intramusclar injection of glycerol, while phosphate-buffered saline (PBS) was injected in 20 control rats. Magnetic resonance (MR) images of the kidneys were obtained, before injection of MSCs, after 1 hour, after 1, 2, and 4 days respectively. The MR imaging findings were correlated with the distribution of transplanted MSCs. The kidney injury was histologically evaluated, and the expression of proliferating cell nuclear antigen (PCNA) protein was examined. The Renal function was estimated by quantitative analysis.
Results: In the rat model of ARF the labelled MSCs showed a bilateral loss of signal intensity in the outer zone of the renal cortex on T2*-weighted MR images, which was visible up to 4 days after transplantation. Labelled MSCs were detected in glomerular capillaries by histological examination, the corresponding areas where signal intensity decreased in MR images. Compared to the control group, those ARF rats with MSCs injection had less renal injury, more enhanced tubular cell proliferation and better renal function.
Conclusions: MR imaging visualises those intravascularly administered MSCs in vivo, which promoted recovery of ARF.