自体外周血干细胞移植治疗周围神经损伤

背景：关于神经干细胞对周围神经损伤的治疗已有多篇报道,但外周血干细胞对周围神经损伤治疗鲜有报道。 目的：探讨自体外周血干细胞移植治疗周围神经损伤使失神经骨骼肌重获神经再支配的临床应用。 方法：应用外周血干细胞治疗周围神经损伤6例,同时与周围神经损伤单纯行神经断端吻合或神经移植10例比较。2组患者术后常规肌注鼠神经生长因子一两个疗程,同时给予针灸、理疗、经皮电刺激治疗及功能康复训练。 结果与结论：两组患者随访均超过6个月。干细胞移植组运动神经传导速度和感觉神经传导速度的恢复率要明显高于单纯神经吻合组。提示周围神经损伤后给予修复局部用外周血干细胞移植能够使远端失神经骨骼肌早期重新获得神经再支配。     

干细胞移植治疗肝硬化

背景：干细胞是具有自我更新和分化能力的细胞,可分化为肝系细胞。研究表明,干细胞移植治疗肝硬化患者有显示良好疗效的一些报告。 目的：对脐血干细胞移植、骨髓干细胞移植、外周血干细胞移植治疗肝硬化的研究予以分析,为肝硬化治疗提供新的手段。 方法：CNKI数据库中2002/2011检索有关干细胞移植与肝硬化的治疗文献,检索词为“肝硬化(liver/hepatic cirrhosis);失代偿性肝硬化(decompensated cirrhosis);外周静脉(peripheral vein);干细胞(stem cell);移植(transplantation);脐血干细胞(umbilical cord blood stem cell, UCBSC);骨髓干细胞(bone marrow stem cell, BMSCS);自体骨髓干细胞(autologous bone marrow stem cell);外周血干细胞(peripheral blood stem cell)”,共检索文献130篇。 结果与结论：干细胞作为一类具有自我更新扩增和多向分化潜能的细胞,在一定的条件下可分化为多种功能细胞。目前临床上治疗肝硬化所使用的干细胞主要有3种：脐血干细胞、骨髓干细胞、外周血干细胞。干细胞移植治疗肝硬化的临床应用虽刚刚起步,但有取得良好疗效的多篇报告。多数患者接受治疗后临床症状好转,肝功能改善,并且此方法操作简单易行,价格低廉,避免了免疫排斥又不涉及伦理道德等问题,具有可创性前景。     

骨髓间充质干细胞与新型神经导管复合材料修复周围神经缺损

背景：随着医学模式的不断发展进步,人们对于外周神经缺损的治疗以及后期康复水平提出更高的要求,这就使得以干细胞培养为基础的神经组织工程技术为神经缺损治疗提供了新策略。 目的：探讨骨髓间充质干细胞与新型神经导管复合材料修复周围神经缺损的可行性。 方法：选取清洁级纯种新西兰大白兔50只,采用随机数字表法分为实验组与对照组,每组25只,于兔前肢桡骨中段约15 mm处造成外周神经损伤,造模后1周,实验组外周神经损伤处移植骨髓间充质干细胞联合新型神经导管复合材料,对照组外周神经损伤处移植骨髓间充质干细胞。移植后4周,取神经损伤处的神经纤维长约5 mm,进行苏木精-伊红染色和扫描电镜观察,对比两组再生神经组织内神经纤维的密度和直径。 结果与结论：实验组神经纤维密度明显高于对照组,神经纤维直径明显低于对照组,组间相比差异有显著性意义(P < 0.05);实验组再生神经组织表面细胞数较多,细胞生长状态良好,体积较大,胞体发出多个突起,并且细胞之间相互连接交织成网状,其轴突较长和较粗,呈典型的神经元样细胞表现,且生长密度和状态优于对照组,可见骨髓间充质干细胞与新型神经导管复合材料可以用于修复周围神经缺损,且效果确切。 中国组织工程研究杂志出版内容重点：干细胞;骨髓干细胞;造血干细胞;脂肪干细胞;肿瘤干细胞;胚胎干细胞;脐带脐血干细胞;干细胞诱导;干细胞分化;组织工程     

谷氨酰胺诱导nestin阳性大鼠骨髓间充质干细胞分化为施万细胞样细胞

<正>组织工程技术的发展为外周神经损伤提供了新的治疗方法[1],尤其在较长的外周神经缺损中可以解决自体神经移植供源不足的问题。近些年研究表明,施万(Schwann)细胞在外周神经发育和促进外周神经的再生和修复中起着重要的作用[2-3]。施万细胞作为外周神经组织工程中重要的种子细胞之一,但是自体来源的施万细胞数量和增殖能力有限,不能满足组织工程化的需要,因此获得充足的细胞用于移植成了问题的关键。骨髓间充质干细胞(bone     

干细胞移植治疗系统性硬化的研究进展

系统性硬化(systemic sclerosis,SSc)的治疗一直是临床上的难题,现有的治疗手段难以满足患者需求。造血干细胞移植(hematopoietic stem cell transplantation,HSCT)在临床上的发展已相对成熟,近年来其在SSc上的临床试验取得了突破进展,但移植相关并发症问题一直有待...     

干细胞移植治疗糖尿病足

背景：以自体骨髓、脐血单个核细胞移植治疗糖尿病足,对缺血性病变及周围神经损伤所致临床症状有改善作用,对糖尿病足也有较好的疗效。脐带间充质干细胞与骨髓干细胞和脐血干细胞相比有其自身的优势。 目的：观察脐带间充质干细胞移植治疗糖尿病足病缺血及神经损伤的疗效。 方法：选取2010至2012年住院行脐带间充质干细胞移植治疗的糖尿病足病患者32例,将脐带间充质干细胞稀释后行双下肢肌肉内注射,每个注射点间隔约3 cm,每个肢体移植(5.02±1.37) ×108个。于3个月和6个月后评价其下肢缺血和下肢周围神经病变情况。并检索CNKI数据库,对国内干细胞移植治疗糖尿病足的研究状况进行分析。 结果与结论：移植后踝肱指数升降不一,移植后6个月疼痛评分及冷感评分明显改善,间歇性跛行及皮肤温度、经皮氧分压治疗后3,6个月与移植前比较差异均有显著性意义;对神经病变损伤自觉症状评分、临床检查评分、振动感觉阀值移植后6个月与移植前比较差异有显著性意义。腓浅神经、胫神经感觉神经传导速度,腓总神经、胫神经运动神经传导速度,在移植后3个月与移植前比较,差异无显著性意义(P > 0.05),移植6个月与移植前相比较有升高,差异有显著性意义(P < 0.05)。可见脐带间充质干细胞可以改善糖尿病缺血性病变及周围神经病变的临床症状及客观指标。文献分析结果发现,已有的研究中治疗结果都比较理想,多数研究中的移植方法为进行肌肉注射。     

MT1-MMP 基因敲除细胞的诱导多能干细胞系的构建

目的: 观察野生型鼠和膜1型基质金属蛋白酶( MT1-MMP )基因敲除鼠的成纤维细胞重新编程为诱导多能干细胞(iPSCs)后,其细胞特性是否具有胚胎干细胞(ESCs)相似的潜能。方法: 利用逆转录病毒介导 Oct3/4、Sox2、c-Myc和Klf4 四种基因,转染到野生型鼠和 MT1-MMP 基因敲除鼠的成纤维细胞中。iPSCs克隆形成后,用免疫细胞化学检测ESCs特异性标志的表达情况。体外将iPSCs通过"悬滴法"向内皮细胞和心肌细胞分化,以检测其分化能力。结果: 转染野生型鼠和 MT1-MMP 基因敲除鼠的成纤维细胞2周后,可见ESCs样克隆开始形成。iPSCs明显表达ESCs特异性标志物碱性磷酸酶(AP)、阶段特异性胚胎抗原-1(SSEA-1)和八聚体结合转录因子3/4(OCT3/4)。诱导分化的内皮细胞表达早期内皮标志物Flk-1/KDR;诱导分化的心肌细胞出现跳动,表达心肌标志物肌钙蛋白I。结论: 野生型鼠和 MT1-MMP 基因敲除鼠的成纤维细胞可被重新编程为iPSCs,iPSCs具有ESCs的特征及增殖分化能力,因此可能为再生医学的研究和临床上进行细胞移植治疗提供理想的种子细胞来源。     

干细胞在心肌梗死治疗中的应用

近年来，干细胞的研究进展，给心肌梗死的治疗带来了新的希望，干细胞移植也成为了当前研究的热点问题。骨髓干细胞、胚胎干细胞、骨骼肌成肌细胞等已被应用于心肌的再生。研究表明，干细胞移植能有效地改善梗死心肌的功能，但其作用机制尚不完全明了。本研究对干细胞移植治疗心肌梗死研究中取得的成就、有待解决的问题以及临床应用前景作了一个总的评述。     

失神经施万细胞在周围神经损伤修复中的作用与机制

有关神经损伤后再生修复的研究已经历半个多世纪的时间,但至今仍没有基于神经损伤修复机制的突破性疗法应用于临床.基于施万细胞(Schwann cell)替代治疗的部分实验成功使干细胞移植及其构建的组织工程神经成为神经损伤修复的研究热点[1-2],然而其机制并不十分清楚,可能涉及细胞替代、营养作用、髓鞘化及稳定生长微环境等方面[3-5].目前研究主要集中在获得理想的干细胞源,以及干细胞移植后在体内的演变及对神经功能恢复的影响,但却忽视了宿主失神经施万细胞在干细胞治疗中的演变及其作用.成功的神经再生修复是由于移植细胞成功替代了宿主施万细胞还是支持或活化了退行性变中的宿主失神经施万细胞?至今未见相关报道.研究失神经施万细胞在干细胞移植过程中的演变及其作用,这对深入探究干细胞移植修复周围神经损伤的机制有着重要意义.现主要对近些年来国内外关于失神经施万细胞在周围神经损伤修复中的作用和施万细胞表型的改变对周围神经修复的影响及作用机制予以综述.     

干细胞移植与心脏疾病治疗

干细胞是一类具有自我更新能力和分化潜能的细胞,在临床上应用干细胞移植技术可治疗心脏疾病,主要应用于急性心肌梗死、扩张型心肌病和心脏的起搏治疗。干细胞移植的主要途径包括经外周静脉注射、经冠状动脉注射、心内膜注射、经心外膜直视注射及干细胞自体动员。此项技术的开展使临床获益很大,但同时也存在一些问题亟待解决,如移植的安全性、移植细胞数量的选择、移植后的评价问题等。该学科尚在进一步发展中。     

干细胞与周围神经损伤修复

目前周围神经缺损的修复仍是临床的一大难题。周围神经系统具有再生的潜能,但在自体神经移植中受到取材长度的限制,近年来许多学者将体外培养扩增的大量雪旺细胞种植到神经导管中,以引导周围神经再生,然而在适当条件下难以维持大量的雪旺细胞,雪旺细胞传代后形态和功能逐渐改变。体外培养的干细胞,尤其是中枢来源的干细胞,具有低免疫原性,可以分化为雪旺细胞,移植至受损部位后可促进神经再生。本文综述了干细胞在修复周围神经损伤中的应用及其在再生过程中所发挥的作用。     

Schwann cell response on polypyrrole substrates upon electrical stimulation

Current injury models suggest that Schwann cell (SC) migration and guidance are necessary for successful regeneration and synaptic reconnection after peripheral nerve injury. The ability of conducting polymers such as polypyrrole (PPy) to exhibit chemical, contact and electrical stimuli for cells has led to much interest in their use for neural conduits. Despite this interest, there has been very little research on the effect that electrical stimulation (ES) using PPy has on SC behavior. Here we investigate the mechanism by which SCs interact with PPy in the presence of an electric field. Additionally, we explored the effect that the adsorption of different serum proteins on PPy upon the application of an electric field has on SC migration. The results indicate an increase in average displacement of the SC with ES, resulting in a net anodic migration. Moreover, indirect effects of protein adsorption due to the oxidation of the film upon the application of ES were shown to have a larger effect on migration speed than on migration directionality. These results suggest that SC migration speed is governed by an integrin- or receptor-mediated mechanism, whereas SC migration directionality is governed by electrically mediated phenomena. These data will prove invaluable in optimizing conducting polymers for their different biomedical applications such as nerve repair.     

Supplementation of acellular nerve grafts with skin derived precursor cells promotes peripheral nerve regeneration

Introduction of autologous stem cells into the site of a nerve injury presents a promising therapy to promote axonal regeneration and remyelination following peripheral nerve damage. Given their documented ability to differentiate into Schwann cells (SCs) in vitro, we hypothesized that skin-derived precursor cells (SKPs) could represent a clinically-relevant source of transplantable cells that would enhance nerve regeneration following peripheral nerve injury. In this study, we examined the potential for SKP-derived Schwann cells (SKP–SCs) or nerve-derived SCs to improve nerve regeneration across a 12 mm gap created in the sciatic nerve of Lewis rats bridged by a freeze-thawed nerve graft. Immunohistology after 4 weeks showed survival of both cell types and early regeneration in SKP seeded grafts was comparable to those seeded with SCs. Histomorphometrical and electrophysiological measurements of cell-treated nerve segments after 8 weeks survival all showed significant improvement as compared to diluent controls. A possible mechanistic explanation for the observed results of improved regenerative outcomes lies in SKP–SCs' ability to secrete bioactive neurotrophins. We therefore conclude that SKPs represent an easily accessible, autologous source of stem cells for transplantation therapies which act as functional Schwann cells and show great promise in improving regeneration following nerve injury.     

Skin-derived Precursors as a Source of Progenitors for Cutaneous Nerve Regeneration

Peripheral nerves have the potential to regenerate axons and reinnervate end organs. Chronic denervation and disturbed nerve regeneration are thought to contribute to peripheral neuropathy, pain, and pruritus in the skin. The capacity of denervated distal nerves to support axonal regeneration requires proliferation by Schwann cells, which guide regenerating axons to their denervated targets. However, adult peripheral nerve Schwann cells do not retain a growth-permissive phenotype, as is required to produce new glia. Therefore, it is believed that following injury, mature Schwann cells dedifferentiate to a progenitor/stem cell phenotype to promote axonal regrowth. In this study, we show that skin-derived precursors (SKPs), a recently identified neural crest-related stem cell population in the dermis of skin, are an alternative source of progenitors for cutaneous nerve regeneration. Using in vivo and in vitro three-dimensional cutaneous nerve regeneration models, we show that the SKPs are neurotropic toward injured nerves and that they have a full capacity to differentiate into Schwann cells and promote axon regeneration. The identification of SKPs as a physiologic source of progenitors for cutaneous nerve regeneration in the skin, where SKPs physiologically reside, has important implications for understanding early cellular events in peripheral nerve regeneration. It also provides fertile ground for the elucidation of intrinsic and extrinsic factors within the nerve microenvironment that likely play essential roles in cutaneous nerve homeostasis. STEM Cells2012;30:2261-2270.     

The role of basic fibroblast growth factor in peripheral nerve regeneration

In the peripheral nervous system regeneration and gradual functional restoration occur following peripheral nerve injury. Growth of regenerating axons depends on the presence of diffusible neurotrophic factors, in addition to the substratum. Neurotrophic factors that are involved in peripheral nerve regeneration include nerve growth factor, brain-derived neurotrophic factor, ciliary neurotrophic factor, glial cell line-derived neurotrophic factor, and interleukin-6. Recent functional and expression studies of basic fibroblast growth factor and its receptors have emphasized a physiological role of these molecules in the peripheral nervous system. Basic fibroblast growth factor and its receptors are constitutively expressed in dorsal root ganglia and the peripheral nerve. These molecules display an upregulation in dorsal root ganglia and in the proximal and distal nerve stumps following peripheral nerve injury. In the ganglia these molecules show a mainly neuronal expression, whereas at the lesion site of the nerve, Schwann cells and invading macrophages represent the main cellular sources of basic fibroblast growth factor and the receptors 1–3. Exogenously applied basic fibroblast growth factor mediates rescue effects on injured sensory neurons and supports neurite outgrowth of transectioned nerves. Regarding the expression pattern and the effects after exogenous administration of basic fibroblast growth factor, this molecule seems to play a physiological role during nerve regeneration. Thus, basic fibroblast growth factor could be a promising candidate to contribute to the development of new therapeutic strategies for the treatment of peripheral nerve injuries.     

Recellularized nerve allografts with differentiated mesenchymal stem cells promote peripheral nerve regeneration

Chemical-extracted acellular nerve allografting, containing the natural nerve structure and elementary nerve extracellular matrix (ECM), has been used for peripheral nerve-defect treatment experimentally and clinically. However, functional outcome with acellular nerve allografting decreases with increased size of gap in nerve defects. Cell-based therapy is a good strategy for repairing long nerve defects. Bone-marrow-derived mesenchymal stem cells (BMSCs) and adipose-derived mesenchymal stem cells (ADSCs) can be induced to differentiate into cells with Schwann cell-like properties (BMSC-SCs or ADSC-SCs), which have myelin-forming ability in vitro and secrete trophic nerve growth factors. Here, we aimed to determine whether BMSC-SCs or ADSC-SCs are a promising cell type for enriching acellular grafts in nerve repair. We evaluated axonal regeneration distance by immunofluorescence staining after 2-week implantation. We used functional and histomorphometric analysis to evaluate 3-month regeneration of the novel cell-supplemented tissue-engineered nerve graft used to bridge a 15-mm-long sciatic nerve gap in rats. Introducing BMSC-SCs or ADSC-SCs to the acellular nerve graft promoted sciatic nerve regeneration and functional recovery. Nerve regeneration with BMSC-SCs or ADSC-SCs was comparable to that with autografting and Schwann cells alone and better than that with acellular nerve allografting alone. Differentiated bone-marrow-or adipose-derived MSCs may be a promising cell source for tissue-engineered nerve grafts and promote functional recovery after peripheral nerve injury.     

雪旺氏细胞的发育、存活及其调控机制

雪旺氏细胞 (schwann cells,SC)是周围神经系统的胶质细胞 ,在神经再生过程中起到至关重要的作用。本文阐述SC的发育、存活及其相关的调控因子 ,了解了 SC及其前体的生物学特性 ,轴突源性 Neuregulin和 SC自分泌调控的信号对其存活的调控 ,以及 SC凋亡的调控 ,以便在体外模拟体内环境大量扩增 SC,解决目前组织工程神经修复中的难点     

Efficient Generation of Schwann Cells from Human Embryonic Stem Cell-Derived Neurospheres

Schwann cells (SC), the glial cells of peripheral nerves, are involved in many diseases including Charcot Marie Tooth and neurofibromatosis, and play a pivotal role in peripheral nerve regeneration. Although it is possible to obtain human SC from nerve biopsies, they are difficult to maintain and expand in culture. Here we describe an efficient system for directing the differentiation of human embryonic stem cells (hESC) into cells with the morphological and molecular characteristics of SC. Neurospheres were generated from hESC using stromal cell induction and grown under conditions supportive of SC differentiation. After 8 weeks, hESC-derived SC expressed characteristic markers GFAP, S100, HNK1, P75, MBP and PMP-22, and were observed in close association with hESC-derived neurites. ~60% of the cells were double-immunostained for the SC markers GFAP/S100. RT-PCR analysis confirmed the expression of GFAP, S100, P75, PMP-22 and MBP and demonstrated expression of the SC markers P0, KROX20 and PLP in the cultures. Expression of CAD19 was observed in 2 and 4 week cultures and then was down-regulated, consistent with its expression in SC precursor, but not mature stages. Co-culture of hESC-derived SC with rat, chick or hESC-derived axons in compartmentalized microfluidic chambers resulted in tight association of the SC with axons. Apparent wrapping of the axons by SC was occasionally observed, suggestive of myelination. Our method for generating SC from hESC makes available a virtually unlimited source of human SC for studies of their role in nerve regeneration and modeling of disease.     

组织工程化神经修复周围神经创伤的应用

背景：近年来,随着生物工程技术以及组织工程化神经的发展给周围神经缺损的治疗带来了新的希望,已逐渐成为研究的焦点。 目的：从种子细胞、生物材料以及构建周围神经组织技术3个方面综述组织工程方法修复周围神经损伤的新进展。 方法：由第一作者在2013年7月应用计算机检索PubMed 数据库及CNKI 数据库,英文关键词为“tissue engineering,peripheral nerves,nerve injuries,stem cells,schwann cells,scaffold,growth factor”,中文关键词为“组织工程,周围神经,神经损伤,干细胞,许旺细胞,支架,生长因子”。选择内容与神经组织工程、周围神经损伤修复相关的文章,同一领域文献则选择近期发表或发表在权威杂志文章,共纳入63篇文献。 结果与结论：现阶段组织工程方法修复周围神经损伤的研究虽已取得很大进展,但大多停留于实验探索阶段。将组织工程神经应用于临床尚存下列问题亟待解决：①种子细胞来源及伦理。②细胞扩增后移植的免疫排斥。③移植细胞稳定性问题及致瘤性。④神经支架材料的降解速度、最佳孔隙率、导管厚度、形状等。⑤体外神经构建后移植修复时机。⑥各种神经生物因子的局部释放与调控等等。随着科技的发展,期待上述问题的解决,从而使得众多临床神经损伤患者受益。     

干细胞移植治疗脊髓损伤的实验研究进展

目的:探讨脊髓损伤后干细胞移植对神经功能恢复的作用机制及临床疗效.方法:检索国内外报道的实验大鼠脊髓损伤造模后干细胞移植的相关文献,对实验结果进行综合分析,评估大鼠神经功能恢复效果.结果:胚胎干细胞、神经干细胞、骨髓间充质干细胞、许旺细胞、嗅鞘细胞移植到受损脊髓实验大鼠后可分化成不同功能类型的神经细胞,能释放促进宿主神经元再生的营养因子,重建轴突的连续性.结论:脊髓损伤后干细胞移植可重建脊髓神经传导的连续性,预示着干细胞在脊髓损伤的治疗中具有良好的应用前景.