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ObjectiveThis study aimed to evaluate the hypotheses that administration routes [intra-arterial (IA) vs. intravenous (IV)] affect the early stage migration of transplanted human bone marrow-derived mesenchymal stem cells (hBM-MSCs) in acute brain infarction.MethodsMale Sprague-Dawley rats (n=40) were subjected to photothrombotic infarction. Three days after photothrombotic infarction, rats were randomly allocated to one of four experimental groups [IA group : n=12, IV group : n=12, superparamagnetic iron oxide (SPIO) group : n=8, control group : n=8]. All groups were subdivided into 1, 6, 24, and 48 hours groups according to time point of sacrifice. Magnetic resonance imaging (MRI) consisting of T2 weighted image (T2WI), T2* weighted image (T2*WI), susceptibility weighted image (SWI), and diffusion weighted image of rat brain were obtained prior to and at 1, 6, 24, and 48 hours post-implantation. After final MRI, rats were sacrificed and grafted cells were analyzed in brain and lung specimen using Prussian blue and immunohistochemical staining.ResultsGrafted cells appeared as dark signal intensity regions at the peri-lesional zone. In IA group, dark signals in peri-lesional zone were more prominent compared with IV group. SWI showed largest dark signal followed by T2*WI and T2WI in both IA and IV groups. On Prussian blue staining, IA administration showed substantially increased migration and a large number of transplanted hBM-MSCs in the target brain than IV administration. The Prussian blue-positive cells were not detected in SPIO and control groups.ConclusionIn a rat photothrombotic model of ischemic stroke, selective IA administration of human mesenchymal stem cells is more effective than IV administration. MRI and histological analyses revealed the time course of cell migration, and the numbers and distribution of hBM-MSCs delivered into the brain.

The three assays had dissimilar performance of HPV screening capacity and exhibited moderate level of concordance in HPV genotyping. These discrepant results were unavoidable due to difference in type-specific analytical sensitivity and lack of standardization; therefore, we suggested that the efforts to standardization of HPV genotyping kits and adjusting analytical sensitivity would be important for the best clinical performance.

Background:Susceptibility-weighted imaging (SWI) is extremely sensitive in the detection of superparamagnetic iron oxide (SPIO) nanoparticle-labeled cells. However, no study has compared molecular imaging for stem cell detection using SWI and other MRI pulse sequences.Objectives:This study aims to assess the sensitivity of SWI in detecting SPIO nanoparticle-labeled, human bone marrow-derived mesenchymal stem cells (SPIO-hMSCs) compared with that of T2- and T2*-weighted imaging (T2WI and T2*WI, respectively) in a phantom and in vivo study in rats.Materials and Methods:A phantom was prepared with various cell concentrations. In one normal rat, SPIO-hMSCs were implanted directly through burr holes into both caudate putamens, while in three rats without and six rats with photothrombotic infarction, 2.5 × 105/ml SPIO-hMSCs were infused into the ipsilateral internal carotid artery (ICA). T2WI, T2*WI, and SWI findings were compared for dark regions representing SPIO-hMSCs.Results:SWI and T2*WI detected 15 µL of 13 SPIO-hMSCs/µL and 15 µL of 27 SPIO-hMSCs/µL in the phantom, respectively and 3 µL of 333 SPIO-hMSCs/µL and 3 µL of 167 SPIO-hMSCs/µL in the normal rat brain (direct implantation). In the normal rat brain (ICA infusion), one of the three cases showed numerous foci of dark regions dispersed throughout the brain on T2*WI and SWI. Dark regions surrounded the infarcts in all six infracted rat brains. The dark region was most prominent on SWI, followed by T2*WI and T2WI in all six rats (P = 0.002). Implanted SPIO-hMSCs were confirmed using Prussian blue staining.Conclusions:SWI is the most sensitive in the detection of SPIO-hMSCs, with the dark regions representing SPIO-hMSCs being more prominent on SWI than on T2*WI and T2WI.