Efficiently tracking of stem cells in vivo using different kinds of superparamagnetic iron oxide in swine with myocardial infarction / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Superparamagnetic iron oxide (SPIO) particles have shown much promise as a means to visualize labeled cells using molecular magnetic resonance imaging (MRI). Micrometer-sized superparamagnetic iron oxide (MPIO) particles and nanometer-sized ultrasmall superparamagnetic iron oxide (USPIO) are two kinds of SPIO widely used for monitoring stem cells migration. Here we compare the efficiency of two kinds of SPIO during the use of stem cells to treat acute myocardial infarction (AMI).</p><p><b>METHODS</b>An AMI model in swine was created by 60 minutes of balloon occlusion of the left anterior descending coronary artery. Two kinds of SPIO particles were used to track after intracoronary delivered 10(7) magnetically labeled mesenchymal stem cells (MR-MSCs). The distribution and migration of the MR-MSCs were assessed with the use of 3.0T MR scanner and then the results were confirmed by histological examination.</p><p><b>RESULTS</b>MR-MSCs appeared as a local hypointense signal on T₂*-weighted MRI and there was a gradual loss of the signal intensity after intracoronary transplantation. All of the hypointense signals in the USPIO-labeled group were found on T₂*-weighted MRI, contrast to noise ratio (CNR) decreased in the MPIO-labeled group (16.07 ± 5.85 vs. 10.96 ± 1.34) and USPIO-labeled group (11.72 ± 1.27 vs. 10.03 ± 0.96) from 4 to 8 weeks after transplantation. However, the hypointense signals were not detected in MPIO-labeled group in two animals. MRI and the results were verified by histological examination.</p><p><b>CONCLUSIONS</b>We demonstrated that two kinds of SPIO particles in vitro have similar labeling efficiency and viability. USPIO is more suitable for labeling stem cells when they are transplanted via a coronary route.</p>

Effects of autologous mesenchymal stem cells transfected with heme oxygenase-1 gene transplantation on ischemic Swine hearts / 中华心血管病杂志

<p><b>OBJECTIVE</b>To observe the effect of intracoronary transfer of autologous HO-1 overexpressed MSCs in porcine model of myocardial ischemia (1 h)/reperfusion.</p><p><b>METHODS</b>Apoptosis was assayed and cytokine concentrations in supernatant were measured in cells exposed to hypoxia-reoxygen in vitro. In vivo, Chinese male mini-pigs were allocated to the following treatment groups: control group (saline), MSCs group (MSCs), MSCs transfected with pcDNA3.1-nHO-1 (HO-1-MSCs). 1 x 10(7) of autologous stem cells or identical volume of saline was injected intracoronary into porcine hearts 1 h after ischemia. MRI assay and postmortem analysis were assessed 3 months after stem cell transplantation.</p><p><b>RESULTS</b>In vitro, cell apoptosis rate post hypoxia-reoxygen was significantly reduced in HO-1-MSCs group (30.30% +/- 7.64%) compared with that in MSCs group (56.93% +/- 4.68%, P < 0.001) and LacZ-MSCs group (55.88% +/- 4.38%, P < 0.001), VEGF was also significantly upregulated in HO-1-MSCs group [(768.44 +/- 78.38) pg/ml] compared with that in MSCs group [(555.27 +/- 67.67) pg/ml, P < 0.001] and LacZ-MSCs group [(522.97 +/- 71.45) pg/ml, P < 0.001]. In vivo, cardiac function was significantly improved in both MSCs transplantation groups compared to saline group (all P < 0.05 vs.saline) and the left ventricular ejection fraction was significantly higher in HO-1-MSCs group compared with that in MSCs group at 3 months after transplantation (53.50% +/- 2.09% vs. 49.54% +/- 2.74%, P = 0.017), capillary density in the peri-infarct area was also significantly higher in HO-1-MSC group than that in MSCs group [(14.59 +/- 2.39)/HPF vs. (11.78 +/- 2.48)/HPF, P = 0.033].</p><p><b>CONCLUSIONS</b>Efficacy of HO-1 overexpressed MSCs on improving cardiac function and promoting angiogenesis was greater than those by MSCs in this porcine ischemia/reperfusion model.</p>

Therapeutic effects of magnetically labeled mononuclear and mesenchymal stem cells transplantation in a swine myocardial infarction model assessed by magnetic resonance imaging / 中华心血管病杂志

<p><b>OBJECTIVE</b>To evaluate the therapeutic effects of magnetically labeled mononuclear stem cells (MR-MNC) and mesenchymal stem cells (MR-MSC) transplantation in a swine acute myocardial infarction (AMI) model by MR imaging.</p><p><b>METHODS</b>AMI model was established in swines by balloon occlusion of the left anterior descending coronary artery, 10(7) autologous MR-MSC (n = 7), MR-MNC (n = 6) or PBS (n = 6) were delivered via intracoronary infusion within 1 week after AMI [(4.8 +/- 1.3) days]. Changes of infarct size and cardiac function were assessed with the use of 3.0T MR scanner before AMI, at 1 and 8 weeks post AMI.</p><p><b>RESULTS</b>Magnetically labeled stem cells could be identified in the region of AMI by cardiac MR imaging. Eight weeks post transplantation, infarct size was significantly reduced in MR-MSC transplantation group (8.5% +/- 0.5% vs. 24.7% +/- 3.1%, P < 0.05) and in MR-MNC transplantation (12.3% +/- 1.5% vs. 26.1% +/- 1.5%, P < 0.05) while infarct size remained unchanged in PBS group (P > 0.05) compared to values at 1 week post AMI, left ventricular ejection fraction (LVEF) was also significantly higher in MR-MSC transplantation group (56.9% +/- 1.3% vs. 40.7% +/- 2.0%, P < 0.05) and MR-MNC transplantation group (52.8% +/- 1.4% vs. 41.9% +/- 3.3%, P < 0.05) compared to LVEF at 1 week post AMI. LVEF increase was more significant in swines received MR-MSC transplantation than MR-MNC transplantation (16.2% +/- 1.2% vs. 10.9% +/- 3.0%, P < 0.05). Prussian blue staining identified stem cells in corresponding myocardial regions with as by MRI. Western blot analysis demonstrated that cardiac expressions of myosin heavy chain (MHC) in MR-MSC group (100.3 +/- 5.5) and in MR-MNCs group (95.5 +/- 4.2) were significantly higher than that in PBS group (75.7 +/- 5.7, P < 0.05), myocardial troponin T (cTNT) expression in MR-MSC group (124.0 +/- 5.8) and MR-MNC group (118.4 +/- 4.4) were also significantly higher than in PBS group (93.3 +/- 3.9, P < 0.05) while MMP2/TIMP1 ratios in MR-MSC group (0.6 +/- 0.1) and MR-MNC group (0.6 +/- 0.1) were significantly lower than that in PBS group (4.2 +/- 0.2, P < 0.05).</p><p><b>CONCLUSIONS</b>Magnetically labeled MR-MSC and MR-MNC homed to heart post myocardial infarction and reduced infarct size, improved cardiac function. MR-MSC is superior to MR-MNC on improving cardiac function.</p>

Transplantation of magnetically labeled mesenchymal stem cells improves cardiac function in a swine myocardial infarction model / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Mesenchymal stem cells (MSCs) transplantation provides a new approach for myocardial repair. However, many important fundamental questions about MSCs transplantation remain unanswered. There is an urgent need to identify MSCs from the beating heart and analyze the efficacy of this new approach. This study aimed to localize the magnetically labeled MSCs (MR-MSCs) and monitor the restorative effects of MR-MSCs with magnetic resonance (MR) imaging.</p><p><b>METHODS</b>Acute myocardial infarction (AMI) was created in swine by a balloon occlusion of the left anterior descending coronary artery. Cells were delivered via intracoronary infusion after myocardial infarction. Infarct size change and cardiac function were assessed with 3.0T MR scanner. The results were then confirmed by histological and western blot analysis. All statistical procedures were performed with Systat (SPSS version 12.01).</p><p><b>RESULTS</b>A total of 26 swine were divided into four groups (sham-operated group, n=6; AMI group with PBS transplantation, n=6; labeled MSCs group, n=7; unlabeled MSCs group, n=7). MSCs, MR-MSCs (10(7) cells) or PBS were delivered by intracoronary injection after MI and serial cardiac MR imaging studies were performed at 0, 4 and 8 weeks after transplantation. MR imaging demonstrated MI size decreased after MSCs transplantation in labeled and unlabeled groups, however, increases were seen in the AMI group at 8 weeks after MI. The left ventricular ejection fraction (LVEF) was slightly increased in the AMI group ((41.87+/-2.45)% vs (39.04+/-2.80)%, P>0.05), but significantly improved in the MR-MSCs group ((56.85+/-1.29)% vs (40.67+/-2.00)%, P<0.05) and unlabeled group ((55.38+/-1.07)% vs (41.78+/-2.08)%, P<0.05) at 8 weeks after treatment. MR-MSCs were further confirmed by Prussian blue and immunofluorescent staining. Western blot analysis demonstrated that there was an increased expression of cardiomyocyte markers such as myosin heavy chain and troponin T in the MSCs treatment groups and the ratio of matrix metalloproteinase 2 to tissue inhibitor of metalloproteinase 1 decreased in the labeled group and unlabeled group compared with the AMI group and sham-operated group.</p><p><b>CONCLUSION</b>Transplanted MR-MSCs can regenerate new myocardium and prevent remolding in an MI model at 2-month follow-up and represent a preferred method to better understand the mechanisms of stem cell therapy in future clinical studies.</p>

Expression of human HSF in E. coli and its effects on mobilization of hematopoietic stem cells in rhesus monkeys / 中华血液学杂志

<p><b>OBJECTIVE</b>To study the expression of hHSF in E. coli and its effect on the mobilization of hematopoietic stem/progenitor cells.</p><p><b>METHODS</b>The hHSF gene was obtained by overlapping PCR and cloned into the vector pET30a to yield pET30a-hHSF, which was transformed into E. coli BL21(DE3) and expressed with IPTG induction. Subsequently, rhHSF was purified by gel filtration and cation exchange chromatography and subjected to refolding. Molecular weight of hHSF was measured by MALDI-TOF Mass Spectroscopy. The N terminal amino acid sequence rhHSF was determined by protein sequencing. rhHSF was profiled in rhesus monkey for mobilization of peripheral blood stem cells. Eight rhesus monkeys were equally divided into two groups. The first group was administered single subcutaneous injection of 500 microg/kg hHSF, while the other one was administered 10 microg.kg(-1).d(-1) G-CSF for 4 days followed by a single subcutaneous injection of 500 microg/kg rhHSF.</p><p><b>RESULTS</b>The sequence coding hHSF was confirmed by sequencing and the induced-expression level was about 30% of total cell proteins. The purity of target protein was over 95%. The sequence of N terminal 10 amino acids and the amino acid composition were consistent with the theoretical parameters; molecular weight of rhHSF was 7540. The peripheral CD34(+) cells, CFU-GM yields, and neutrophils peaked at 3 h (16.3-folds increase compared with baseline), 1 h (1.9-folds increase) and 45 min (4.4-folds increase) respectively after the single injection of rhHSF. The addition of rhHSF after the last dose of G-CSF boosted these levels to 25.8-folds, 8.7-folds and 8.3-folds respectively.</p><p><b>CONCLUSION</b>hHSF is highly expressed in E. coli and rapidly mobilizes the hematopoietic stem/progenitor cells and neutrophils in rhesus monkeys. hHSF shows distinct synergistic effect with G-CSF.</p>