多模式追踪食蟹猴骨髓间充质干细胞

近年来, 在细胞治疗和再生医学领域, 自体或异体细胞移植治疗疾病正在成为现实. 骨髓间充质干细胞具有分化成多种细胞的潜能, 已被广泛用于各种疾病的研究和治疗. 活体追踪移植细胞, 检测移植细胞的生存及功能状态对于评价移植治疗效果至关重要. 目前, 利用磁共振对比剂超顺磁性氧化铁颗粒(SPIO), 活体追踪和监测标记细胞已被广泛用于动物实验研究和一些临床疾病诊断. 但 MRI 信号不能显示移植细胞在体内的生物学特征. 本研究中, 对食蟹猴骨髓间充质干细胞体外标记Molday ION rhodamine-B^TM(MIRB), 探讨MIRB 标记后cMSCs 的细胞生物学特性, 以及脑内移植后的活体MRI 影像学及组织学追踪. 结果表明, MIRB 具有生物组织相容性, 能高效标记cMSCs, 可用于体内多模式追踪移植细胞, 为利用MIRB 追踪和检测移植细胞, 以及干细胞移植治疗机制的研究提供资料.     

骨髓间充质干细胞在大鼠体内的迁移研究

目的:将体外预先标记的骨髓间充质干细胞(mesenchymalstemcells,MSCs)移植到大鼠脑内观察细胞的存活和转归,从在体(invivo)角度阐明MSCs在中枢神经系统疾病细胞治疗中的潜在应用前景。首先用DiI在体外标记MSCs。将标记后的MSCs分别移植到大鼠纹状体和侧脑室,在移植后2w和4w灌杀动物,进行脑组织及脊髓的冰冻切片,在荧光显微镜下观察细胞的存活与转归。结果:移植到纹状体的MSCs可沿针道向周围实质迁移,迁移的最远距离可达0.2mm。并且,在大脑皮层及其他脑实质的血管壁、血管中以及血管周围还可见到标记细胞;而移植到侧脑室的MSCs则主要沿脑室系统迁移,细胞主要分布在移植侧侧脑室,对侧脑室与第四脑室也有分布,也有少量细胞沿侧脑室向周围实质迁移,迁移的最远距离为0.23mm。还可见到沿胼胝体向对侧脑室迁移的细胞流,甚至有个别细胞迁移至脊髓腰段。所有动物在细胞移植后4周均未发现肿瘤形成。结论:MSCs脑内移植后可以在中枢神经系统内存活并迁移,无致瘤性。结果提示骨髓间充质细胞是很多疾病细胞与基因治疗的有力工具。     

对比不同年龄段食蟹猴骨髓间充质干细胞的生物学特征

骨髓间充质干细胞因其广泛的临床应用前景而备受关注.非人灵长类动物在基因、生理和代谢等方面与人类相似,在制作疾病模型和疾病治疗研究等方面具有无可比拟的优势.因此,来源于非人灵长类的骨髓间充质干细胞是细胞移植和组织工程研究中的重要工具.本实验对比研究了不同年龄段食蟹猴骨髓间充质干细胞的生物学特征.结果发现,与中年食蟹猴骨髓间充质干细胞比较,青少年食蟹猴骨髓间充质干细胞具有明显高的增殖和分化潜能.长期体外培养的食蟹猴骨髓间充质干细胞能发生自发转变,转变后的细胞具有明显不同于骨髓间充质干细胞的形态特征.端粒酶活性检测显示,各年龄组不同代数的骨髓间充质干细胞端粒酶活性没有明显差别,但与骨髓间充质干细胞比较,转变后的细胞端粒酶活性显著增高.另一方面,随着体外培养时间延长,染色体不稳定性发生频率相应增加.这些结果提示在使用间充质干细胞进行实验或临床研究前,必须全面考虑各种因素,包括供体的年龄等,并且完善各种检测.     

人骨髓间充质干细胞脑内移植对食蟹猴脑出血的治疗作用

目的评价人骨髓间充质干细胞脑内移植对食蟹猴脑出血模型的治疗作用。方法符合普通级标准的成年食蟹猴12只,用自体股动脉抗凝血脑内注射方法建模后1周,用脑立体定位法在血肿周围植入人骨髓间充质干细胞,细胞数分别为高剂量5×106、低剂量1×106、对照组等体积生理盐水。利用MRI、PET、神经功能缺损评分和组织病理学对干细胞移植效果进行评价。结果神经功能评分显示干细胞移植1周后动物神经功能明显改善。PET结果显示干细胞移植后2周高剂量组血肿周围皮层、基底节核团的SUV%值与对照组间存在显著性差异(P=0.02)。移植后3周高、低剂量组血肿周围皮层、基底节核团的SUV%值与对照组间差异存在显著性(P值分别为0.03和0.04)。MRI显示剂量组血肿吸收速度大于对照组。病理检查可见剂量组坏死灶面积小于对照组,出血灶周围有大量新生血管生成,剂量组与对照组间差异存在显著性(P<0.01)。结论在损伤脑组织周围移植hBMSC可促进食蟹猴损伤神经组织的恢复,为hBMSC治疗脑出血的临床应用提供了重要实验依据。     

应用小动物活体成像追踪观察EGFP标记的间充质干细胞

为探讨干细胞移植治疗过程中干细胞在体内的存活和迁移能力,利用非细胞损伤性的EGFP(enhanced green fl uorescence protein)标记间充质干细胞进行了实验研究。该研究用电穿孔方法将加强的绿色荧光蛋白表达质粒p CMV-EGFP(cytomegalovirus-EGFP plasmid)转染细胞产生具有EGFP标记的牙髓干细胞、皮肤成纤维细胞(skin fi broblast cells,SFCs)和脐带间充质干细胞。将EGFP标记的脐带间充质干细胞注射到裸鼠皮下,用小动物活体成像系统观察了EGFP标记细胞在体内移植后细胞存活能力和荧光强度随时间的变化情况。结果表明,电穿孔转染能够在体外产生高效表达EGFP的标记细胞,EGFP在牙髓干细胞、SFCs和脐带间充质干细胞中的表达率分别为80%、85%和80%。通过小动物活体成像系统检测表明,EGFP标记的脐带间充质干细胞注射到裸鼠皮下后EGFP荧光表达在7 d后逐渐下降,但免疫组化分析表明,移植细胞可存活6个月以上。该研究提示,EGFP标记的干细胞可用于体内追踪其存活、迁移及分化,为探讨干细胞移植治疗作用提供了实验证据。     

慢病毒介导EGFP转染骨髓间充质干细胞在胶质瘤模型中迁移分布的研究

目的:如何证实骨髓间充质干细胞(BMSCs)是胶质瘤基因治疗中最好的药物载体?将增强型绿色荧光蛋白(EGFP)标记的大鼠骨髓间充质干细胞移植入大鼠C6胶质瘤模型脑内,观察骨髓间充质干细胞在肿瘤内的迁徙与定位。方法:贴壁法培养大鼠骨髓细胞获取纯化的BMSCs。慢病毒介导EGFP转染BMSCs,于荧光显微镜下观察EGFP的表达,并行流式细胞仪检测EGFP阳性转染率。利用立体定向仪将培养好的C6细胞注入大鼠脑内,建立大鼠脑内胶质瘤模型。将标记EGFP的BMSCs利用微量注射器注入模型鼠脑内;移植后第1,7天处死大鼠,用荧光显微镜观察BMSCs在肿瘤内的迁移分布。结果:实验成功建立了大鼠脑内胶质瘤模型。以EGFP标记的BMSCs在模型鼠脑内主动迁移分布于肿瘤内部及肿瘤与正常脑组织交界侧。结论:骨髓间充质干细胞可以作为肿瘤基因治疗的良好载体。     

人脐带间充质干细胞食蟹猴连续静脉输注后免疫毒性与免疫调节作用研究

该文旨在研究人脐带间充质干细胞在食蟹猴体内的免疫毒性与免疫调节特性。连续14天给予食蟹猴不同剂量(2.0×10~6个·kg~(-1)和2.0×10~7个·kg~(-1))的人脐带间充质干细胞静脉滴注,检测食蟹猴血清IgG浓度、抗人脐带间充质干细胞抗体、淋巴细胞活化增殖和T细胞亚群的变化,以及胸腺和脾脏组织学变化。结果显示,连续14天静脉给予人脐带间充质干细胞对食蟹猴血清IgG浓度无影响,不刺激动物产生抗人脐带间充质干细胞抗体。人脐带间充质干细胞显著抑制食蟹猴淋巴细胞的活化增殖,降低CD3~(+)T细胞比例,刺激Treg细胞的增殖分化。组织学检查发现,部分动物出现与给药相关的胸腺皮质萎缩和脾脏淋巴生发中心增多增大。该研究得出,人脐带间充质干细胞的免疫毒性极低,静脉输注后不引起食蟹猴体内免疫排斥等异常反应,提示其在临床上异体应用的安全性。     

移植骨髓间充质干细胞源性神经元样细胞治疗大鼠脊髓损伤

目的:研究骨髓间充质干细胞源性神经元样细胞移植治疗成鼠脊髓损伤的可行性。方法:选取成年SD大鼠32只,两只用以提取骨髓间充质干细胞,其余被分为3组,其中细胞移植组10只,PBS缓冲液组10只,空白对照组10只。骨髓间充质干细胞分离传代培养并诱导成神经元样细胞后用Hoechst33342标记,损伤1周后采取静脉注射移植的方法移植于大鼠脊髓损伤区,移植六周后用免疫荧光方法检测细胞的存活及与宿主脊髓的整合情况。脊髓损伤后的1~6周对各组动物进行BBB评分,用SPSS12.0进行数据分析。结果:细胞移植组动物的BBB评分提高显著,于其他两组差异有统计学意义。细胞移植组免疫荧光显示,移植细胞在体内大量存活并桥接于脊髓损伤区的两端,存活的多数细胞神经元特异性标记物NSE、NF-200、星形胶质细胞特异性标记物GFAP表达呈阳性。结论:移植定向诱导的神经元样细胞有助于大鼠脊髓损伤后的功能恢复。     

骨髓间充质干细胞移植修复大鼠半横断脊髓损伤

目的初步探讨骨髓间充质干细胞诱导为神经细胞,及其移植对大鼠脊髓半横断损伤神经功能恢复和运动的影响。方法贴壁培养法分离培养大鼠骨髓间充质干细胞(mesenchymal stem cells,MSCs),大鼠脊髓匀浆上清诱导第3代向神经细胞分化,经免疫组化鉴定分化后细胞的性质。制备大鼠半横断脊髓损伤模型,脊髓损伤局部注射BrdU标记诱导后的神经细胞。细胞移植5周后观察移植细胞在脊髓内存活分布情况。结果倒置显微镜下可见MSCs呈纺锤形和多角形,有1~2个核仁,经脊髓匀浆上清诱导后,发出数个细长突起,并交织成网,诱导后的细胞表达Nestin,可推测诱导后的细胞为MSCs源神经细胞。5周后移植的MSCs在宿主损伤脊髓内聚集并存活,表达MAP-2、NF、GFAP与对照组比较有统计学意义(P0.05)。大鼠运动功能较移植前有所改善。结论MSCs经脊髓匀浆上清诱导后移植治疗大鼠半横断脊髓损伤可使运动功能得到改善。     

IL-10在人骨髓间充质干细胞移植治疗食蟹猴脑缺血中的作用

目的探讨食蟹猴脑缺血模型在人骨髓间充质干细胞（human bone marrow-derived mesenchymal stem cells,hBMSCs）移植后IL-10的表达及其对脑缺血损伤的保护作用。方法食蟹猴8只,在脑定位仪定位下,应用光化学法构建食蟹猴脑缺血模型,并将其随机分为高剂量治疗组、低剂量治疗组和模型组,分别在脑缺血部位附近注射高、低密度的hBMSCs和生理盐水。手术后,通过影像学、神经功能评分及组织病理学观察对hBMSC的治疗效果进行评价。并应用原位细胞凋亡检测的方法观察脑缺血周围神经细胞的凋亡情况。应用免疫组织化学、RT-PCR以及real-time PCR法检测检测脑损伤周围IL-10的表达水平。结果与模型组相比,hBMSC治疗组损伤部位周围细胞凋亡明显减少,免疫组织化学显示[L-IO阳性细胞的数量及染色强度均较模型组明显升高,IL-10在mRNA水平表达也明显升高。结论hBMSCs对食蟹猴脑缺血模型具有修复作用,其治疗机制可能与促进炎症抑制因子IL-10的表达有关。     

Labeling of cynomolgus monkey bone marrow-derived mesenchymal stem cells for cell tracking by multimodality imaging

Recently, transplantation of allogeneic and autologous cells has been used for regenerative medicine. A critical issue is monitoring migration and homing of transplanted cells, as well as engraftment efficiency and functional capability in vivo. Monitoring of superparamagnetic iron oxide (SPIO) particles by magnetic resonance imaging (MRI) has been used in animal models and clinical settings to track labeled cells. A major limitation of MRI is that the signals do not show biological characteristics of transplanted cells in vivo. Bone marrow mesenchymal stem cells (MSCs) have been extensively investigated for their various therapeutic properties, and exhibit the potential to differentiate into cells of diverse lineages. In this study, cynomolgus monkey MSCs (cMSCs) were labeled with Molday ION Rhodamine-B™ (MIRB), a new SPIO agent, to investigate and characterize the biophysical and MRI properties of labeled cMSCs in vitro and in vivo. The results indicate that MIRB is biocompatible and useful for cMSCs labeling and cell tracking by multimodality imaging. Our method is helpful for detection of transplanted stem cells in vivo, which is required for understanding mechanisms of cell therapy.     

In vitro labeling of human umbilical cord mesenchymal stem cells with superparamagnetic iron oxide nanoparticles

Human umbilical cord mesenchymal stem cells (hUC‐MSCs) transplantation has been shown to promote regeneration and neuroprotection in central nervous system (CNS) injuries and neurodegenerative diseases. To develop this approach into a clinical setting it is important to be able to follow the fates of transplanted cells by noninvasive imaging. Neural precursor cells and hematopoietic stem cells can be efficiently labeled by superparamagnetic iron oxide (SPIO) nanoparticle. The purpose of our study was to prospectively evaluate the influence of SPIO on hUC‐MSCs and the feasibility of tracking for hUC‐MSCs by noninvasive imaging. In vitro studies demonstrated that magnetic resonance imaging (MRI) can efficiently detect low numbers of SPIO‐labeled hUC‐MSCs and that the intensity of the signal was proportional to the number of labeled cells. After transplantation into focal areas in adult rat spinal cord transplanted SPIO‐labeled hUC‐MSCs produced a hypointense signal using T2‐weighted MRI in rats that persisted for up to 2 weeks. This study demonstrated the feasibility of noninvasive imaging of transplanted hUC‐MSCs. J. Cell. Biochem. 108: 529–535, 2009. © 2009 Wiley‐Liss, Inc.     

Effect of transplantation route on stem cell migration to fibrotic liver of rats via cellular magnetic resonance imaging

Background aimsAssessing mesenchymal stromal cells (MSCs) after grafting is essential for understanding their migration and differentiation processes. The present study sought to evaluate via cellular magnetic resonance imaging (MRI) if transplantation route may have an effect on MSCs engrafting to fibrotic liver of rats.MethodsRat MSCs were prepared, labeled with superparamagnetic iron oxide and scanned with MRI. Labeled MSCs were transplanted via the portal vein or vena caudalis to rats with hepatic fibrosis. MRI was performed in vitro before and after transplantation. Histologic examination was performed. MRI scan and imaging parameter optimization in vitro and migration under in vivo conditions were demonstrated.ResultsStrong MRI susceptibility effects could be found on gradient echo-weighted, or T21-weighted, imaging sequences from 24 h after labeling to passage 4 of labeled MSCs in vitro. In vivo, MRI findings of the portal vein group indicated lower signal in liver on single shot fast spin echo-weighted, or T2-weighted, imaging and T21-weighted imaging sequences. The low liver MRI signal increased gradually from 0–3 h and decreased gradually from 3 h to 14 days post-transplantation. The distribution pattern of labeled MSCs in liver histologic sections was identical to that of MRI signal. It was difficult to find MSCs in tissues near the portal area on day 14 after transplantation; labeled MSCs appeared in fibrous tuberculum at the edge of the liver. No MRI signal change and a positive histologic examination were observed in the vena caudalis group.ConclusionsThe portal vein route seemed to be more beneficial than the vena caudalis on MSC migration to fibrotic liver of rats via MRI.     

Magnetic resonance imaging of ferumoxide-labeled mesenchymal stem cells in cartilage defects: in vitro and in vivo investigations

The purpose of this study was to (1) compare three different techniques for ferumoxide labeling of mesenchymal stem cells (MSCs), (2) evaluate if ferumoxide labeling allows in vivo tracking of matrix-associated stem cell implants (MASIs) in an animal model, and (3) compare the magnetic resonance imaging (MRI) characteristics of ferumoxide-labeled viable and apoptotic MSCs. MSCs labeled with ferumoxide by simple incubation, protamine transfection, or Lipofectin transfection were evaluated with MRI and histopathology. Ferumoxide-labeled and unlabeled viable and apoptotic MSCs in osteochondral defects of rat knee joints were evaluated over 12 weeks with MRI. Signal to noise ratios (SNRs) of viable and apoptotic labeled MASIs were tested for significant differences using t-tests. A simple incubation labeling protocol demonstrated the best compromise between significant magnetic resonance signal effects and preserved cell viability and potential for immediate clinical translation. Labeled viable and apoptotic MASIs did not show significant differences in SNR. Labeled viable but not apoptotic MSCs demonstrated an increasing area of T2 signal loss over time, which correlated to stem cell proliferation at the transplantation site. Histopathology confirmed successful engraftment of viable MSCs. The engraftment of iron oxide-labeled MASIs by simple incubation can be monitored over several weeks with MRI. Viable and apoptotic MASIs can be distinguished via imaging signs of cell proliferation at the transplantation site.     

成体心脏干细胞经静脉移植后在心梗小鼠体内的分布研究

目的：观察心肌梗死小鼠静脉移植成体心脏干细胞后,细胞在小鼠体内各器官的分布情况。明确心梗后静脉移植成体心脏干 细胞在小鼠体内的分布和归巢情况。方法：分离培养小鼠心脏成体干细胞,采用流式细胞仪鉴定细胞,通过亲脂性染料CM-DiI标 记细胞后行小鼠急性心肌梗死模型建立和细胞移植,分别在细胞移植后7、14、8 天取小鼠心脏、肝脏、脑、脊髓、肺脏,行冰冻切 片,在荧光显微镜下观察移植细胞在各组织器官存活和分布情况。结果：成体心脏干细胞分离培养后呈贴壁生长,流式细胞仪检 测显示细胞纯度>80%。CM-DiI标记后荧光显微镜下观察可见标记的细胞胞浆胞核均被染成呈明亮的红色。心肌梗死后经静脉 移植成体心脏干细胞,细胞在各组织中分布呈变化过程,7 天时,在肺脏和肝脏分布较多,至14 天和28 天时,肺脏和肝脏分布减 少,心脏分布逐渐增多,表现出向心脏的" 归巢" 现象,而脑和脊髓在28 天的观察时间内分布较少。结论：采用CM-DiI标记心 脏成体干细胞,操作简单,标记效果好,可用于短期的细胞体内追踪。小鼠心肌梗死后行经静脉成体心脏干细胞移植,28 天后细胞 在心脏的分布逐渐增多,表现出向心脏的" 归巢" 现象。     

Spontaneous transformation of adult mesenchymal stem cells from cynomolgus macaques in vitro

Mesenchymal stem cells (MSCs) have shown potential clinical utility in cell therapy and tissue engineering, due to their ability to proliferate as well as to differentiate into multiple lineages, including osteogenic, adipogenic, and chondrogenic specifications. Therefore, it is crucial to assess the safety of MSCs while extensive expansion ex vivo is a prerequisite to obtain the cell numbers for cell transplantation. Here we show that MSCs derived from adult cynomolgus monkey can undergo spontaneous transformation following in vitro culture. In comparison with MSCs, the spontaneously transformed mesenchymal cells (TMCs) display significantly different growth pattern and morphology, reminiscent of the characteristics of tumor cells. Importantly, TMCs are highly tumorigenic, causing subcutaneous tumors when injected into NOD/SCID mice. Moreover, no multiple differentiation potential of TMCs is observed in vitro or in vivo, suggesting that spontaneously transformed adult stem cells may not necessarily turn into cancer stem cells. These data indicate a direct transformation of cynomolgus monkey MSCs into tumor cells following long-term expansion in vitro. The spontaneous transformation of the cultured cynomolgus monkey MSCs may have important implications for ongoing clinical trials and for models of oncogenesis, thus warranting a more strict assessment of MSCs prior to cell therapy.     

Experimental Study on Trace Marking and Oncogenicity of Neural Stem Cells Derived from Bone Marrow

It has been well accredited that the neural stem cells (NSCs) derived from bone marrow stroma cells (BMSCs) can be used as the therapeutic application. However, their efficacy and safety in therapeutic application are uncertain. In this experiment, the trace marking and oncogenicity of NSCs derived from BMSCs (BMSCs-D-NSCs) were studied. The BMSCs were harvested by gradient centrifugation and cultured in "NSCs medium" in vitro. The verified CD133/Nestin-positive BMSCs-D-NSCs were then transplanted into nude mice to detect the oncogenicity, into the right lateral cerebral ventricle or right caudae putamen and substantia nigra to examine, whether the symptoms were improved in Parkinson's Disease (PD) models after transplantation, by both SPECT image assay of dopamine transporter (DAT) in corpus striatum and its average standard uptake value (SUVave) in corpus striatum and thalamus. Tissue samples and surviving model animals were studied at 1, 3, and 6 months post-transplantation. Before transplantation, the cells were labeled with BrdU or rAAV-GFP for the pathological sections, and with Feridex for the in vivo trace by MRI assay. The concanavalin A (ConA) agglutination test, stop-dependence test with soft agar, karyotype analysis of chromosome G zone in BMSCs-D-NSCs, and the nude mouse neoplasia test were also performed. The BrdU, rAAV-GFP or Feridex can be used as trace markers of BMSCs-D-NSCs during transplantation. The transplanted BMSCs-D-NSCs displayed neither toxicity nor neoplasia up to 6 months in vivo, but could play an important role in improving the symptoms of the animals with degenerative diseases like PD.     

Quantum dot labeling of mesenchymal stem cells

Background  

Mesenchymal stem cells (MSCs) are multipotent cells with the potential to differentiate into bone, cartilage, fat and muscle cells and are being investigated for their utility in cell-based transplantation therapy. Yet, adequate methods to track transplanted MSCs in vivo are limited, precluding functional studies. Quantum Dots (QDs) offer an alternative to organic dyes and fluorescent proteins to label and track cells in vitro and in vivo. These nanoparticles are resistant to chemical and metabolic degradation, demonstrating long term photostability. Here, we investigate the cytotoxic effects of in vitro QD labeling on MSC proliferation and differentiation and use as a cell label in a cardiomyocyte co-culture.     

Superparamagnetic Iron Oxide Nanoparticles Function as a Long-Term,Multi-Modal Imaging Label for Non-Invasive Tracking of Implanted Progenitor Cells

The purpose of this study was to determine the ability of superparamagnetic iron oxide (SPIO) nanoparticles to function as a long-term tracking label for multi-modal imaging of implanted engineered tissues containing muscle-derived progenitor cells using magnetic resonance imaging (MRI) and X-ray micro-computed tomography (μCT). SPIO-labeled primary myoblasts were embedded in fibrin sealant and imaged to obtain intensity data by MRI or radio-opacity information by μCT. Each imaging modality displayed a detection gradient that matched increasing SPIO concentrations. Labeled cells were then incorporated in fibrin sealant, injected into the atrioventricular groove of rat hearts, and imaged in vivo and ex vivo for up to 1 year. Transplanted cells were identified in intact animals and isolated hearts using both imaging modalities. MRI was better able to detect minuscule amounts of SPIO nanoparticles, while μCT more precisely identified the location of heavily-labeled cells. Histological analyses confirmed that iron oxide particles were confined to viable, skeletal muscle-derived cells in the implant at the expected location based on MRI and μCT. These analyses showed no evidence of phagocytosis of labeled cells by macrophages or release of nanoparticles from transplanted cells. In conclusion, we established that SPIO nanoparticles function as a sensitive and specific long-term label for MRI and μCT, respectively. Our findings will enable investigators interested in regenerative therapies to non-invasively and serially acquire complementary, high-resolution images of transplanted cells for one year using a single label.     

Migration, fate and in vivo imaging of adult stem cells in the CNS

Adult stem cells have been intensively studied for their potential use in cell therapies for neurodegenerative diseases, ischemia and traumatic injuries. One of the most promising cell sources for autologous cell transplantation is bone marrow, containing a heterogenous cell population that can be roughly divided into hematopoietic stem and progenitor cells and mesenchymal stem cells (MSCs). MSCs are multipotent progenitor cells that, in the case of severe tissue ischemia or damage, can be attracted to the lesion site, where they can secrete bioactive molecules, either naturally or through genetic engineering. They can also serve as vehicles for delivering therapeutic agents. Mobilized from the marrow, sorted or expanded in culture, MSCs can be delivered to the damaged site by direct or systemic application. In addition, MSCs can be labeled with superparamagnetic nanoparticles that allow in vivo cell imaging. Magnetic resonance imaging (MRI) is thus a suitable method for in vivo cell tracking of transplanted cells in the host organism. This review will focus on cell labeling for MRI and the use of MSCs in experimental and clinical studies for the treatment of brain and spinal cord injuries.