Effects of heme oxygenase-1 gene modulated mesenchymal stem cells on vasculogenesis in ischemic swine hearts / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Mesenchymal stem cells (MSCs) transplantation may partially restore heart function in the treatment of acute myocardial infarction (AMI). The aim of this study was to explore the beneficial effects of MSCs modified with heme xygenase-1 (HO-1) on post-infarct swine hearts to determine whether the induction of therapeutic angiogenesis is modified by the angiogenic cytokines released from the implanted cells.</p><p><b>METHODS</b>In vitro, MSCs were divided into four groups: (1) non-transfected MSCs (MSCs group), (2) MSCs transfected with the pcDNA3.1-Lacz plasmid (Lacz-MSCs group), (3) MSCs transfected with pcDNA3.1-hHO-1 (HO-1-MSCs group), and (4) MSCs transfected with pcDNA3.1-hHO-1 and pretreatment with an HO inhibitor, tin protoporphyrin (SnPP) (HO-1-MSCs + SnPP group). Cells were cultured in an airtight incubation bottle for 24 hours, in which the oxygen concentration was maintained at < 1%, followed by 12 hours of reoxygenation. After hypoxia/reoxygen treatment, ELISA was used to measure transforming growth factor (TGF-β) and fibroblast growth factor (FGF-2) in the supernatant. In vivo, 28 Chinese mini-pigs were randomly allocated to the following treatment groups: (1) control group (saline), (2) Lacz-MSCs group, (3) HO-1-MSCs group, and (4) HO-1-MSCs + SnPP group. About 1 × 10(7) of autologous stem cells or an identical volume of saline was injected intracoronary into porcine hearts 1 hour after MI. Magnetic resonance imaging (MRI) assay and postmortem analysis were assessed four weeks after stem cell transplantation.</p><p><b>RESULTS</b>Post hypoxia/reoxygenation in vitro, TGF-β in the supernatant was significantly increased in the HO-1-MSCs ((874.88 ± 68.23) pg/ml) compared with Lacz-MSCs ((687.81 ± 57.64) pg/ml, P < 0.001). FGF-2 was also significantly increased in the HO-1-MSCs ((1106.48 ± 107.06) pg/ml) compared with the Lacz-MSCs ((853.85 ± 74.44) pg/ml, P < 0.001). In vivo, at four weeks after transplantation, HO-1 gene transfer increased the capillary density in the peri-infarct area compared with the Lacz-MSCs group (14.24 ± 1.66/HPFs vs. 11.51 ± 1.34/HPFs, P < 0.001). Arteriolar density was also significantly higher in HO-1-MSCs group than in the Lacz-MSCs group (7.86 ± 2.00/HPFs vs. 6.45 ± 1.74/HPFs, P = 0.001). At the same time, the cardiac function was significantly improved in the HO-1-MSCs group compared with the Lacz-MSCs group ((53.17 ± 3.55)% vs. (48.82 ± 2.98)%, P < 0.05). However, all these effects were significantly abrogated by SnPP.</p><p><b>CONCLUSION</b>MSCs provided a beneficial effect on cardiac function after ischemia/reperfusion by the induction of therapeutic angiogenesis, and this effect was amplified by HO-1 overexpression.</p>

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>

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>