In vivo magnetic resonance imaging of iron oxide-labeled, arterially-injected mesenchymal stem cells in kidneys of rats with acute ischemic kidney injury: detection and monitoring at 3T

PURPOSE: To evaluate MRI for a qualitative and quantitative in vivo tracking of intraaortal injected iron oxide-labeled mesenchymal stem cells (MSC) into rats with acute kidney injury (AKI). MATERIALS AND METHODS: In vitro MRI and R2* measurement of nonlabeled and superparamagnetic iron oxide (SPIO)-labeled MSC (MSC(SPIO)) was performed in correlation to cellular iron content and cytological examination (Prussian blue, electron microscopy). In vivo MRI and R2* evaluation were performed before and after ischemic/reperfusion AKI (N = 14) and intraaortal injection of 1.5 x 10(6) MSC(SPIO) (N = 7), fetal calf serum (FCS) (medium, N = 6), and SPIO alone (N = 1) up to 14 days using a clinical 3T scanner. Signal to noise ratios (SNR), R2* of kidneys, liver, spleen, and bone marrow, renal function (creatinine [CREA], blood urea nitrogen [BUN]), and kidney volume were measured and tested for statistical significance (Student's t-test, P < 0.05) in comparison histology (hematoxylin and eosin [H&E], Prussian blue, periodic acid-Schiff [PAS], CD68). RESULTS: In vitro, MSC(SPIO) showed a reduction of SNR and T2* with R2* approximately number of MSC(SPIO) (R2 = 0.98). In vivo MSC(SPIO) administration resulted in a SNR decrease (35 +/- 15%) and R2* increase (101 +/- 18.3%) in renal cortex caused by MSC(SPIO) accumulation in contrast to control animals (P < 0.01). Liver, spleen, and bone marrow (MSC(SPIO)) showed a delayed SNR decline/R2* increase (P < 0.05) resulting from MSC(SPIO) migration. The increase of kidney volume and the decrease in renal function (P < 0.05) was reduced in MSC-treated animals. CONCLUSION: Qualitative and quantitative in vivo cell-tracking and monitoring of organ distribution of intraaortal injected MSC(SPIO) in AKI is feasible in MRI at 3T.     

人脐带源和胎盘源间充质干细胞的生物学特性比较

目的：探讨人脐带和胎盘来源间充质干细胞（ MSCs）的分离培养和生物学性状的差异,为MSCs的临床应用提供选择依据。方法利用组织贴壁法分离培养脐带MSCs,酶消化法分离培养胎盘MSCs。传代培养后于倒置显微镜下观察两种不同来源的MSCs的细胞形态,流式细胞仪检测两者表面标志物表达的差异,通过细胞周期和群体倍增时间测定比较两者生长增殖能力,体外成骨和成脂诱导比较其分化能力。结果胎盘MSCs和脐带MSCs为贴壁生长、形态均一的成纤维样或长梭形外观,两种细胞均高表达CD90、CD105,不表达CD34、CD45、HLA-DR。胎盘MSCs的群体倍增时间为40．8 h,52．12％处于G0／G1期,脐带MSCs的群体倍增时间为39．5 h,57．50％处于G0／G1期,表明两者增殖能力旺盛,且无明显差异;两者在体外均可诱导分化成骨细胞和脂肪细胞。结论胎盘源MSCs具有与脐带源MSCs相似的生物学特性,两者均可作为临床治疗用细胞或组织工程的种子细胞。     

Magnetosonoporation: Instant magnetic labeling of stem cells

The purpose of this study was to develop an instant MR cell labeling technique, called magnetosonoporation. First, a magnetosonoporation apparatus was successfully established for MR labeling of stem cells. Then, the safety of this new cell labeling approach was confirmed by evaluation of cell viability, proliferation, and differentiation of magnetosonoporation‐labeled and unlabeled C17.2 neural stem cells. Subsequently, the feasibility of using in vivo MRI to detect magnetosonoporation/Feridex‐labeled stem cells was validated in living animals and confirmed by histologic correlation. The magnetosonoporation technique is expected to be convenient, efficient, and safe for future clinical application of MRI‐guided cell therapies. Magn Reson Med 63:1437–1441, 2010. © 2010 Wiley‐Liss, Inc.     

自成人脂肪组织分离与培养间充质干细胞的实验研究

目的 探索成人脂肪组织源性间充质干细胞(ADMSCs)的分离、体外培养,为其将来应用于临床心肌梗死的治疗提供实验依据。方法 无菌条件下获取腹部手术病人大网膜脂肪组织,胰酶消化30min,离心,在含15％胎牛血清的DMEM中,37℃、5％CO2饱和湿度下常规培养,对第2代细胞进行免疫组织化学染色,鉴定其表面分子CD44、HLA-DR及Ⅷ因子。结果 成人脂肪组织中含有大量间充质干细胞,免疫化学染色鉴定除CD44阳性间充质干细胞外,所分离细胞同时含有部分HLA-DR阳性成纤维细胞和Ⅷ因子阳性的血管内皮细胞。结论 建立了一种自人体脂肪组织分离、培养ADMSCs经济简便的方法,为其应用于临床提供了实验依据。     

SWIFT detection of SPIO‐labeled stem cells grafted in the myocardium

We report initial results from studies using sweep imaging with Fourier transformation (SWIFT) to detect superparamagnetic iron oxide (SPIO) particle–labeled stem cells in the rat heart. In experiments performed on phantoms containing titanium balls or SPIO–labeled cells, frequency‐shifted signals surrounding the paramagnetic objects produced a pileup artifact visualized by SWIFT. Total signal intensity was retained to a much greater extent by SWIFT as compared to gradient echo imaging. SWIFT imaging of excised and in vivo hearts showed (a) reduced blooming artifact as compared with gradient echo imaging, which helped reduce ambiguity in the detection of SPIO–labeled cells; (b) enhancement of off‐resonance signals relative to the background in the imaginary component of images; and (c) detailed myocardial anatomy in magnitude images, which provided anatomic reference. These features suggest SWIFT can facilitate the detection of SPIO–laden cells in the cardiovascular system. Magn Reson Med 63:1154–1161, 2010. © 2010 Wiley‐Liss, Inc.     

人脐带Wharton胶中间充质干细胞的分离、培养与鉴定

目的研究人脐带Wharton胶中间充质干细胞(MSCs)的生物学特性。方法去除新鲜人脐带动静脉和脐带外膜组织,获得Wharton胶,分别采用酶消化法和组织块培养法获得脐带Wharton胶中的干细胞,通过细胞传代培养、生长曲线测定、活细胞鉴定进行细胞生长动力学研究,流式细胞仪分析细胞表面分子特点,组织化学和免疫组化染色鉴定软骨特征性标志物表达情况。RT-PCR检测Sox-9及Col-2A1mRNA表达情况。结果采用酶消化法可以快速分离Wharton胶中MSCs,且细胞迅速贴壁生长;组织块法培养获得种子细胞时间较长。流式细胞仪检测显示所获得的细胞表达CD44、CD105等MSCs标志物,HLA-ABC表达阳性,HLA-DPDQDR表达阴性。经过冻存复苏后免疫表型无显著变化。组织化学和免疫组化染色显示脐带Wharton胶MSCs弱表达软骨特征性标志。RT-PCR显示Wharton胶MSCs表达Sox-9和Col-2A1。结论人脐带Wharton胶MSCs不向造血系分化,且具有前软骨细胞的特性,有望作为软骨组织工程新型的种子细胞。     

In vivo MRI of embryonic stem cells in a mouse model of myocardial infarction.

The therapeutic potential of administering stem cells to promote angiogenesis and myocardial tissue regeneration after infarction has recently been demonstrated. Given the advantages of using embryonic stem cells and mouse models of myocardial infarction for furthering the development of this therapeutic approach, the purpose of this study was to determine if embryonic stem cells could be loaded with superparamagnetic iron oxide (SPIO) particles and imaged in a mouse model of myocardial infarction over time using MRI. Mouse embryonic stem cells were labeled with SPIO particles. When incubated with 11.2, 22.4, and 44.8 microg Fe/ml of SPIO particles, cells took up increasing amounts of iron oxide. Embryonic stem cells loaded with SPIO compared to unlabeled cells had similar viability and proliferation profiles for up to 14 days. Free SPIO injected into infarcted myocardium was not observable within 12 hr after injection. After injection of three 10-microl aliquots of 10(7) SPIO-loaded cells/ml into infarcted myocardium, MRI demonstrated that the mouse embryonic stem cells were observable and could be seen for at least 5 weeks after injection. These findings support the ability of MRI to test the long-term therapeutic potential of embryonic stem cells in small animals in the setting of myocardial infarction.     

间充质干细胞的来源及临床应用

在骨髓中存在着一群非造血的干细胞成分———间充质干细胞。间充质干细胞在体外可扩增 ,在体内体外都能被诱导分化为成骨细胞、软骨细胞、脂肪细胞、腱细胞、肌肉细胞、神经细胞和支持造血的基质等。间充质干细胞是多潜能 ,并且易分离培养 ,在体外可被大量扩增。因此 ,间充质干细胞在组织工程、细胞治疗和基因治疗中具有广阔的应用前景。本文对骨髓来源的间充质干细胞的生物学特性和其他间质组织来源的间充质干细胞以及它们在临床上的应用进行了综述     

Long‐term MR cell tracking of neural stem cells grafted in immunocompetent versus immunodeficient mice reveals distinct differences in contrast between live and dead cells

Neural stem cell (NSC)‐based therapy is actively being pursued in preclinical and clinical disease models. Magnetic resonance imaging (MRI) cell tracking promises to optimize current cell transplantation paradigms, however, it is limited by dilution of contrast agent during cellular proliferation, transfer of label from dying cells to surrounding endogenous host cells, and/or biodegradation of the label. Here, we evaluated the applicability of magnetic resonance imaging for long‐term tracking of transplanted neural stem cells labeled with superparamagnetic iron oxide and transfected with the bioluminescence reporter gene luciferase. Mouse neural stem cells were transplanted into immunodeficient, graft‐accepting Rag2 mice or immunocompetent, graft‐rejecting Balb/c mice. Hypointense voxel signals and bioluminescence were monitored over a period of 93 days. Unexpectedly, in mice that rejected the cells, the hypointense MR signal persisted throughout the entire time‐course, whereas in the nonrejecting mice, the contrast cleared at a faster rate. In immunocompetent, graft‐rejecting Balb/c mice, infiltrating leukocytes, and microglia were found surrounding dead cells and internalizing superparamagnetic iron oxide clusters. The present results indicate that live cell proliferation and associated label dilution may dominate contrast clearance as compared with cell death and subsequent transfer and retention of superparamagnetic iron oxide within phagocytes and brain interstitium. Thus, interpretation of signal changes during long‐term MR cell tracking is complex and requires caution. Magn Reson Med, 2011. © 2010 Wiley‐Liss, Inc.     

骨髓和脂肪来源的间充质干细胞治疗2型糖尿病的疗效比较

目的 比较大鼠骨髓和脂肪来源的间充质干细胞在2型糖尿病中的疗效.方法 30只成模2型糖尿病大鼠随机分为3组:糖尿病组(T2DM,n=10)、骨髓间充质干细胞治疗组(BMSC,n=10)及脂肪间充质干细胞治疗组(ADSC,n=10),同期正常大鼠(n=10)作为对照组.干细胞分别从正常大鼠骨髓及腹股沟脂肪组织分离培养获得.制模后和细胞注射后每日检测各组血糖.细胞注射后第7天行空腹糖耐量和胰岛素敏感性实验.胰腺组织行胰岛素/胰高血糖素免疫荧光染色.结果 与T2DM组比较,干细胞注射7d后2型糖尿病大鼠的随机血糖持续缓慢下降,糖耐量及胰岛素敏感性均得以改善,胰岛素抵抗指数(HOMA-IR)降低,胰岛内β细胞数量增加(P＜0.05),但是两种类型的间充质干细胞的疗效并无显著差异.结论 骨髓和脂肪来源的间充质干细胞在2型糖尿病大鼠中的疗效相当,脂肪间充质干细胞可作为2型糖尿病治疗的理想细胞.     

悬滴培养对人脂肪间充质干细胞成骨分化的影响

目的探讨悬滴培养对人脂肪来源间充质干细胞(hADSCs)成骨诱导分化的影响。方法利用酶消化法分离培养hADSCs,采用流式细胞术检测其表面标志的表达。对hADSCs进行悬滴培养,贴壁后添加诱导剂对其进行成骨诱导分化,以平板培养组为对照,诱导分化7d及21d时,利用RT-PCR检测成骨基因Runx2及Osteopontin的表达。结果分离培养的hADSCs表达干细胞表面标志CD44、CD90、CD105,不表达CD34、CD45;悬滴培养3d的hADSCs可形成大小均一的球状三维结构;RT-PCR结果表明,在成骨诱导分化的不同时间点,hADSCs悬滴培养组的成骨基因Runx2及Osteopontin表达均比平板培养组高,表明悬滴培养可促进hADSCs的成骨诱导分化。结论悬滴培养有利于hADSCs的成骨诱导分化,有助于提高其成骨诱导效率。     

肿瘤微环境中间充质干细胞的相关生物学特性分析

目的探讨大鼠骨髓间充质干细胞(BMSCs)在肿瘤微环境中是否获得肿瘤细胞的相关生物学特性而导致恶性转化。方法通过6孔板结合Transwell小室建立间充质干细胞和大鼠C6胶质瘤细胞的共培养体系,以共培养组为实验组,另设单独培养的间充质干细胞作为对照组。于相差显微镜下观察培养后两组细胞的形态学改变;采用流式细胞术(FCM)分析细胞周期变化;采用荧光定量PCR和免疫荧光法检测间充质干细胞mdm2、p53mRNA水平及共培养后两组细胞中p53突变蛋白和mdm2癌蛋白的表达。结果共培养后实验组细胞表现为胶质瘤细胞样形态。细胞周期检测结果显示共培养7d后,对照组G1期细胞占90.48%±6.62%,实验组占82.22%±2.74%,两组间差异无统计学意义(P>0.05);对照组S期细胞占4.66%±4.16%,实验组占7.35%±1.93%,两组间差异亦无统计学意义(P>0.05)。定量PCR及免疫荧光检测显示,实验组p53mRNA水平明显降低,为对照组的0.24倍(P<0.05);部分实验组细胞(24.8%)中表达突变型p53蛋白,而对照组无突变p53蛋白表达(P<0.05)。实验组mdm2mRNA及其蛋白的表达水平...     

In vivo serial evaluation of superparamagnetic iron‐oxide labeled stem cells by off‐resonance positive contrast

MRI is emerging as a diagnostic modality to track iron‐oxide‐labeled stem cells. This study investigates whether an off‐resonance (OR) pulse sequence designed to generate positive contrast at 1.5T can assess the location, quantity, and viability of delivered stem cells in vivo. Using mouse embryonic stem cell transfected with luciferase reporter gene (luc‐mESC), multimodality validation of OR signal was conducted to determine whether engraftment parameters of superparamagnetic iron‐oxide labeled luc‐mESC (SPIO‐luc‐mESC) could be determined after cell transplantation into the mouse hindlimb. A significant increase in signal‐ and contrast‐to‐noise of the SPIO‐luc‐mESC was achieved with the OR technique when compared to a gradient recalled echo (GRE) sequence. A significant correlation between the quantity of SPIO‐luc‐mESC and OR signal was observed immediately after transplantation (R² = 0.74, P < 0.05). The assessment of transplanted cell viability by bioluminescence imaging (BLI) showed a significant increase of luciferase activities by day 16, while the MRI signal showed no difference. No significant correlation between BLI and MRI signals of cell viability was observed. In conclusion, using an OR sequence the precise localization and quantitation of SPIO‐labeled stem cells in both space and time were possible. However, the OR sequence did not allow evaluation of cell viability. Magn Reson Med 60:1269–1275, 2008. © 2008 Wiley‐Liss, Inc.     

Dual in vivo magnetic resonance evaluation of magnetically labeled mouse embryonic stem cells and cardiac function at 1.5 t.

Cell therapy has demonstrated the potential to restore injured myocardium. A reliable in vivo imaging method to localize transplanted cells and monitor their restorative effects will enable a systematic investigation of this therapeutic modality. The dual MRI capability of imaging both magnetically labeled mouse embryonic stem cells (mESC) and their restorative effects on cardiac function in a murine model of acute myocardial infarction is demonstrated. Serial in vivo MR detection of transplanted mESC and monitoring of the mESC-treated myocardium was conducted over a 4-week period using a 1.5 T clinical scanner. During the 4-week duration, the mESC-treated myocardium demonstrated sustained improvement of the left ventricular (LV) ejection fraction and conservation of LV mass. Furthermore, no significant difference of their restorative effects on the cardiac function was created by the magnetic labeling of mESC. Thus, in vivo MRI enables simultaneous detection of transplanted mESC and their therapeutic effect on the injured myocardium.     

丹酚酸B对骨髓间充质干细胞SCF表达的影响

目的研究中药单体丹酚酸B对骨髓间充质干细胞(MSCs)中干细胞因子(stemcell factor,SCF)的影响。方法用贴壁培养法分离、培养和纯化MSCs,取第三代MSCs进行实验。用含不同浓度丹酚酸B的低糖DMEM培养液培养MSCs,ELISA法检测培养24、48、72h的上清中SCF的含量;RT-PCR法检测培养24、48、72h的SCF mRNA的表达。结果膜型和可溶型SCF mRNA均有表达。随着培养时间的增加,0.3μg/ml、3μg/ml、30μg/ml丹酚酸B可明显促进SCF的分泌和SCF mRNA的表达(与空白对照组比较,P<0.05),而0.03μg/ml丹酚酸B组和空白对照组比较无明显差异(P>0.05)。结论丹酚酸B可促进MSCs分泌SCF并促进SCF mRNA的表达,提示SCF可能在中药丹参治疗心肌梗死中发挥了重要作用。     

活性氧介导的铁过载对小鼠骨髓间充质干细胞的影响及其机制探讨

目的建立小鼠骨髓间充质干细胞(BM-MSCs)铁过载(IO)模型,并对铁过载模型小鼠进行去铁及抗氧化治疗,探讨铁过载对小鼠BM-MSCs的损伤作用及活性氧(ROS)在该损伤中的作用机制。方法采用随机区组设计,将40只雄性C57BL/6小鼠随机分为对照组、铁剂(右旋糖酐铁,25mg/ml)组(IO组)、铁剂+去铁治疗(DFX,125mg/kg)组(Fe+DFX组)、铁剂+抗氧化治疗(NAC,40mmol/L)组(Fe+NAC组),每组10只。从小鼠密质骨中分离BM-MSCs培养至P1代,检测BM-MSCs内铁颗粒、不稳定铁(LIP)及ROS水平;利用倍增时间及CCK-8试剂盒检测BM-MSCs增殖情况;采用碱性磷酸酶染色(ALP)、茜素红染色、成骨分化基因检测等方法评估BM-MSCs成骨分化能力;采用油红O染色检测BM-MSCs成脂定向分化能力。结果与对照组相比,铁剂组BM-MSCs内存在明显铁颗粒,LIP及ROS水平明显增高(P<0.05),倍增时间明显延长(2.07±0.14d vs 1.03±0.07d,P<0.01)。DFX组及NAC组倍增时间较铁剂组有所缩短,分别为1.52±0.07d与1.68±0.03d(P<0.05)。与对照组比较,铁剂组BM-MSCs矿化能力及向成骨细胞分化能力下降,成骨基因ALP、RUNX2、OSN表达增强,而成脂定向分化能力增强。在去铁及抗氧化治疗后,上述改变发生部分逆转。结论铁过载可影响小鼠骨髓MSCs的增殖及定向分化能力,其机制可能与铁过载所致ROS升高有关。     

In vitro comparison of the biological effects of three transfection methods for magnetically labeling mouse embryonic stem cells with ferumoxides.

In vivo MRI of stem cells (SCs) is an emerging application to evaluate the role of cell therapy in restoring the injured myocardium. The high spatial and temporal resolution combined with iron-oxide-based intracellular labeling techniques will provide a sensitive, noninvasive, dual imaging modality for both cells and myocardium. In order to facilitate this novel imaging approach, much effort has been directed towards developing efficient transfection methods. While techniques utilizing poly-L-lysine (PLL), protamine sulfate (PS), and electroporation (ELP) have been proposed, the fundamental biological effects of these methods on mouse embryonic SCs (mESC) have not been investigated systematically. In this study a longitudinal in vitro evaluation of cellular viability, apoptosis, proliferation, and cardiac differentiation of magnetically labeled mESC was conducted. No significant difference was seen in these biological parameters among the three transfection methods. However, cardiac differentiation was most attenuated by ELP, and iron uptake was most effective by PS.     

鸢尾素对兔骨髓间充质干细胞成脂分化的影响

 目的 探讨鸢尾素对兔骨髓间充质干细胞(bone-marrow mesenchymal stem cells,BMSCs)成脂分化的影响及其信号机制。方法 分离、培养兔BMSCs,检测鸢尾素对BMSCs增殖的影响。BMSCs成脂诱导后,实时荧光定量PCR(polymerase chain reaction,PCR)检测成脂相关基因PPARγ和C/EBPα的转录表达,油红O染色检测细胞内脂质形成情况,Western blot检测Wnt10a信号蛋白的表达。结果 鸢尾素不影响BMSCs的增殖活性;显著下调PPARγ[成脂诱导第7天,(0.20±0.06)vs(1.00±0.10);成脂诱导第14天,(0.61±0.06)vs(1.00±0.15)]和C/EBPα[成脂诱导第7天,(0.40±0.06)vs(1.00±0.12);成脂诱导第14天,(0.70±0.09)vs(1.00±0.18)]的表达,明显抑制BMSCs成脂分化[(0.45±0.05)vs(0.95±0.10);P<0.05];同时,鸢尾素明显促进Wnt10a表达[(5.01±0.78)vs(1.00±0.25);P<0.05]。结论 鸢尾素可抑制BMSCs脂向分化,其作用与激活Wnt信号通路有关。     

间充质干细胞在多发性硬化症治疗中的应用:全球研究探索与展望

多发性硬化症是青少年群体中最常见的神经系统疾病,目前世界上约200万患者深受其困扰,但面对此类疾病依然没有有效的治疗和干预方法.即使当前针对病理性治疗的标准治疗方案,也仅能减轻多发性硬化症的临床症状,而且存在严重的副作用.因此,寻找有效且副作用小的治疗方法迫在眉睫.动物实验以及早期临床研究业已证明间充质干细胞具有潜在的神经再生和免疫调控能力,为多发性硬化症的治疗带来了更广阔的前景.     

真皮来源间充质干细胞的分离培养及成神经分化的研究

目的：研究真皮来源间充质干细胞的分离培养方法及其向神经细胞分化的条件及可行性。方法：取大鼠真皮组织，采用贴壁传代培养筛选法，分离培养真皮间充质干细胞，流式细胞术检测细胞周期，经β-巯基乙醇诱导，倒置显微镜下观察细胞形态变化，免疫细胞化学方法对分化细胞进行鉴定。结果：分离的早期贴壁的真皮来源间充质干细胞经过连续传代培养至第4代，细胞形态较为均一，86％的细胞处于G0／G1期，细胞表面波形蛋白表达阳性，但因子Ⅷ和角蛋白表达阴性。经β-巯基乙醇诱导，真皮间充质干细胞可向神经细胞分化，细胞突起增多，具有神经元的形态学特征，分化后的细胞表达神经元标志物——神经元特异性烯醇化酶（NSE）、神经微丝（NF-200）。结论：大鼠真皮组织中存在着成体多能干细胞，一定条件下可分化为神经元。提示真皮可能是成体多能干细胞的又—来源，有望在神经组织修复和再生中发挥作用。