神经干细胞移植对Alzheimer病的影响

阿尔茨海默综合征（Alhzeimer disease,AD）是典型的神经退行性疾病,传统治疗方法是药物治疗和外科手术治疗,但长期疗效并不显著。通过移植具有分化为神经元、少突胶质细胞、星形胶质细胞能力的神经干细胞替换AD病中丢失的细胞达到治疗目的。     

干细胞治疗脑损伤的概况与进展

近年来,神经科学研究已经表明了在成人和胎儿的中枢神经系统含有神经祖细胞、神经前体细胞和神经干细胞,它们都能生成新的神经元、星型胶质细胞和少突胶质细胞;最近在神经干细胞研究方面也有进展,包括神经干细胞在体外的选择性扩增、体外定向诱导胚胎干细胞的分化以及脑中神经干细胞的检测等,这些进展都为中枢神经系统损伤或疾病的创新疗法奠定了基础。治疗中枢神经系统损伤或疾病主要有两个方法:①激活内源性神经再生;②细胞替代疗法。以下主要讨论细胞替代疗法的概况与进展。     

补阳还五汤对低糖低氧损伤神经干细胞移行 分化的影响

目的探讨补阳还五汤对低糖低氧损伤神经干细胞移行、分化的影响。方法用低糖低氧损伤神经干细胞模拟脑缺血损伤,随机分组,采用细胞标记、免疫细胞化学法、流式细胞仪观察各组神经干细胞移行、分化情况。结果正常培养下,少量游离的细胞迁移,低糖损伤后迁出细胞数明显增多,治疗2组最多;损伤后F200+/Brdu+细胞和异硫氰酸荧光素-神经微丝(FITC-NF)200标记明显增加,治疗2组与治疗1组、模型组差异有统计学意义(P<0.01或0.05)。结论低糖低氧损伤后神经干细胞移行、分化,补阳还五汤能促进神经干细胞移行、分化。     

EphB4信号通路对人胚胎神经干细胞自我更新、增殖、分化和凋亡的影响

目的本实验旨在研究EphB4是否参与调节了人胚胎神经干细胞的增殖、分化、凋亡活动,并探索其下游信号通路。方法培养原代人胚胎神经干细胞,使用沉默慢病毒与过表达慢病毒转染细胞,分别下调和上调EphB4蛋白表达水平。检测EphB4对细胞增殖、分化、凋亡的影响并探索其下游信号通路。结果 EphB4基因沉默后,抑制细胞增殖及向神经元分化,促进细胞向胶质细胞分化,对细胞凋亡无影响。EphB4基因过表达后,促进细胞增殖及向神经元分化,抑制细胞向胶质细胞分化,对细胞凋亡无影响。EphB4是通过下游信号通路Abl-Cyclin D1调节细胞增殖,此信号通路不参与EphB4在细胞分化方面的调节。结论 EphB4参与调节神经干细胞增殖,而且是决定神经干细胞向神经元分化还是向胶质细胞分化的开关,是调节干细胞增殖、迁移和分化的新信号通路,其很可能成为脑卒中后神经元修复的有效治疗靶点。     

移植维甲酸诱导的人胚神经干细胞在受损大鼠脊髓内的分化及作用

目的 将维甲酸(RA)诱导的人胚神经干细胞移植入受损的大鼠脊髓内，观察大鼠后肢运动功能的变化及细胞的分化情况。方法 实验大鼠30只遭受脊髓中度损伤后7天作移植治疗，实验组分两组：一组移植经维甲酸诱导后的细胞，另一组移植未诱导的细胞；对照组注射等量PBS液。每周一次观察大鼠后肢运动情况，移植后4周，应用免疫组化技术检测移植细胞在大鼠脊髓内的生存和分化情况。结果 实验组大鼠脊髓内见许多移植细胞存在，部分可分化出神经元样细胞，其后肢运动功能优于对照组。其中维甲酸诱导组能分化出神经元样细胞，其促进脊髓功能恢复的能力较另一组更强。结论 维甲酸预处理的神经干细胞在体内能替代缺失的神经细胞，促进受损的脊髓功能恢复．在脊髓损伤的临床治疗中具有潜在的应用价值。     

神经干细胞移植在脊髓损伤中应用的研究进展

长期以来,人们一直认为,人体的神经细胞是终生存活的,并且由于神经元细胞缺乏再生修复能力,因此,一旦遇到损伤,这种细胞的失去也是永久的,只能通过胶质细胞增殖充填,导致相应功能损失的不可逆性.但这一传统认识被20世纪最后十几年神经生物学领域的重要进展所打破,这一进展就是发现成年哺乳动物脑组织内广泛存在着具有多向分化潜能的神经干细胞,并发现其在脊髓损伤修复中的应用潜能.神经干细胞(NSC)具有高度增殖、自我更新及分化能力,在一定条件下能不断进行有丝分裂,分化形成神经细胞、星形胶质细胞和少突胶质细胞.     

神经干细胞概述及治疗视神经损伤的应用进展

神经干细胞是具有自我更新、多向分化潜能的细胞群,能分化成神经元、星形胶质细胞和少突胶质细胞。随着干细胞研究技术的不断发展,通过体外培养神经干细胞,移植整合入视网膜各层并定向诱导分化为目的细胞,有望重建视神经功能。本文就神经干细胞的来源、特性、分化调控机制及移植治疗视神经损伤的应用研究进行综述。     

人胰岛素样生长因子-1重组腺病毒转染C17.2神经干细胞增殖及分化的影响

目的观察人胰岛素样生长因子-1重组腺病毒(Ad-IGF-1)转染对C17.2神经干细胞体外增殖和分化的影响。方法体外培养及鉴定C17.2神经干细胞,Ad-IGF-转染C17.2神经干细胞;Western-blotting法检测IGF-1蛋白的表达,酶联免疫吸附实验(ELISA)检测IGF-1蛋白的表达曲线;MTT检测C17.2神经干细胞增殖,NSE及MBP免疫组化观察C17.2神经干细胞体外分化。结果转染AdIGF-1的C17.2神经干细胞成功表达IGF-1蛋白;IGF-1蛋白在病毒转染5～7d达高峰,13d仍高于转染前,Ad-IGF-1转染后各时间C17.2神经干细胞的增殖与对照组相比有显著差异,Ad-IGF-1转染对c17.2神经干细胞向神经元细胞及神经胶质细胞的分化与对照组相比有显著差异。结论Ad-IGF-1转染c17.2神经干细胞可稳定表达IGF-1,Ad-IGF-1转染促进C17.2神经干细胞的增殖及向神经元细胞和少突胶质细胞的分化。     

人胚胎神经干细胞体外培养及其增殖与分化的研究

目的 建立神经干细胞分离、培养及分化的鉴定技术，观察神经干细胞增殖、分化的特点。方法 从人胚胎海马区分离神经干细胞，采用无血清培养基，进行体外扩增培养、传代。采用免疫细胞化学法鉴定神经干细胞和分化的神经细胞；利用流式细胞仪和细胞生长曲线检测神经干细胞的增殖能力。结果 从人胚胎脑海马区分离的细胞具有增殖和多向分化潜能，可进行传代培养，获得的细胞团中大部分为nestin表达阳性细胞。贴壁分化后可以出现NSE、GFAP表达阳性的细胞。结论 用上述方法分离培养的细胞能表达nestin蛋白，具有自我更新和增殖能力，并具有向神经元、星形胶质细胞分化的潜能，具备神经干细胞的特征，可用于细胞移植等相关研究。     

人胚神经干细胞分离培养与鉴定方法

目的:建立神经干细胞(NSCs)实验室分离、培养方法,为NSCs移植提供细胞源.方法:取4月龄(±15 天)正常孕妇水囊引产胎儿大脑纹状体区组织分离神经干细胞,培养于含碱性成纤维细胞生长因子(bFGF)和B27的无血清培养基;同时利用单细胞克隆技术进行连续传代培养;利用形态学观察和免疫荧光技术检测神经上皮干细胞蛋白Nestin抗原的表达来鉴定神经干细胞.结果:体外培养的干细胞在bFGF和B27培养基中可不断增殖形成细胞球,并出现少量细胞分化.单细胞培养4天即开始分裂,同时伴有个别细胞分化;出现大量神经球一般为15天;分化的细胞在30天开始分解,50天左右基本消失.细胞培养3个月(每月补液1次)仍具有分裂增殖能力.单细胞克隆可连续传代10次,仍具增殖分化能力.液氮冻存6个月的细胞复苏后仍具增殖分化能力.单细胞克隆传代增殖的细胞球经Nestin免疫荧光鉴定,呈阳性结果,证实其胚胎源性.结论:采用bFGF和B27的无血清培养基能促进神经干细胞连续稳定增殖,并有少量分化,细胞体外培养3个月、克隆连续传代10次情况下的细胞仍具有神经干细胞特性.     

Hormesis,Cell Death,and Regenerative Medicine for Neurode-Generative Diseases

Although the adult human brain has a small number of neural stem cells, they are insufficient to repair the damaged brain to achieve significant functional recovery for neurodegenerative diseases and stroke. Stem cell therapy, by either enhancing endogenous neurogenesis, or transplanting stem cells, has been regarded as a promising solution. However, the harsh environment of the diseased brain posts a severe threat to the survival and correct differentiation of those new stem cells. Hormesis (or preconditioning, stress adaptation) is an adaptation mechanism by which cells or organisms are potentiated to survive an otherwise lethal condition, such as the harsh oxidative stress in the stroke brain. Stem cells treated by low levels of chemical, physical, or pharmacological stimuli have been shown to survive better in the neurodegenerative brain. Thus combining hormesis and stem cell therapy might improve the outcome for treatment of these diseases. In addition, since the cell death patterns and their underlying molecular mechanism may vary in different neurodegenerative diseases, even in different progression stages of the same disease, it is essential to design a suitable and optimum hormetic strategy that is tailored to the individual patient.     

Endogenous Neural Stem Cells in the Adult Brain

Despite progress in our understanding molecular mechanisms of neuronal cell death in many central nervous system (CNS) diseases, widely effective treatments remain elusive. Recent studies have shown that neural stem cells (NSCs) are present in the subventricular zone (SVZ) lining the lateral ventricles and the subgranular zone (SGZ) of the hippocampal dentate gyrus (DG) in adult mouse, rat, nonhuman primate, and human brain. Newly generated cells in the SGZ can differentiate into mature, functional neurons and integrate into the DG as granule cells, which are involved in memory formation. In addition, many CNS diseases can stimulate the proliferation of neuronal stem/progenitor cells located in the SVZ and SGZ of the adult rodent brain, and the resulting newborn cells migrate into damaged brain regions, where they express mature neuronal markers. Therefore, it might be possible for damaged cells to be replaced from endogenous neural stem cell pools. However, the capacity of self-repair is obviously not enough. Proliferation, migration, and neuronal differentiation of endogenous NSCs could be manipulated by pharmaceutical tools to reach the adequate benefits for the treatment of CNS diseases. This work is supported in part by National Institute of Health (NIH) grant AG21980 (K.J.).     

胎鼠神经干细胞培养方法的建立及药物对干细胞增殖的影响

目的建立神经干细胞培养模型，观察药物对其增殖能力的影响。方法建立大鼠胎脑神经干细胞的培养方法，并用MTT法和3H-胸腺嘧啶核苷参入法观察黄皮酰胺、丹酚酸A及人参皂苷Rg1等对第2代神经球细胞状态的影响。结果免疫细胞化学结果显示，培养的神经细胞具备干细胞的基本特性；MTT和液闪结果则表明，上述3种药物可不同程度地影响神经干细胞的存活率和/或增殖活性。结论本实验所建立的胚胎大鼠神经干细胞培养模型可以观察到一些有脑保护作用的药物对干细胞存活和增殖有一定影响。     

体外中药干预骨髓间充质干细胞向心肌细胞分化的研究进展

骨髓间充质干细胞具有自我更新、增殖和多向分化的潜能,骨髓间充质干细胞在体外可通过化学药物及中药干预诱导分化为心肌细胞,将其应用于治疗缺血性心脏病,可减少梗死面积,改善心功能,为心脏病的治疗开辟了新途径。大量研究表明,中药在骨髓间充质干细胞增殖和定向分化过程中具有促进作用,不仅可在体内作用于骨髓间充质干细胞促进其增殖、分化,还可通过影响体外微环境促进其功能的建立与存活。     

Stem cells and small molecule screening: haploid embryonic stem cells as a new tool

Stem cells can both self-renew and differentiate into various cell types under certain conditions, which makes them a good model for development and disease studies. Recently, chemical approaches have been widely applied in stem cell biology by promoting stem cell self-renewal, proliferation, differentiation and somatic cell reprogramming using specific small molecules. Conversely, stem cells and their derivatives also provide an efficient and robust platform for small molecule and drug screening. Here, we review the current research and applications of small molecules that modulate stem cell self-renewal and differentiation and improve reprogramming, as well as the applications that use stem cells as a tool for small molecule screening. Moreover, we introduce the recent advance in haploid embryonic stem cells research. Haploid embryonic stem cells maintain haploidy and stable growth over extensive passages, possess the ability to differentiate into all three germ layers in vitro and in vivo, and contribute to the germlines of chimeras when injected into blastocysts. Androgenetic haploid stem cells can also be used in place of sperm to produce fertile progeny after intracytoplasmic injection into mature oocytes. Such characteristics demonstrate that haploid stem cells are a new approach for genetic studies at both the cellular and animal levels and that they are a valuable platform for future small molecule screening.     

Nonclinical safety strategies for stem cell therapies

Recent breakthroughs in stem cell biology, especially the development of the induced pluripotent stem cell techniques, have generated tremendous enthusiasm and efforts to explore the therapeutic potential of stem cells in regenerative medicine. Stem cell therapies are being considered for the treatment of degenerative diseases, inflammatory conditions, cancer and repair of damaged tissue. The safety of a stem cell therapy depends on many factors including the type of cell therapy, the differentiation status and proliferation capacity of the cells, the route of administration, the intended clinical location, long term survival of the product and/or engraftment, the need for repeated administration, the disease to be treated and the age of the population. Understanding the product profile of the intended therapy is crucial to the development of the nonclinical safety study design.     

Stem Cell Transplantation: A Promising Therapy for Parkinson’s Disease

Parkinson’s disease is one of the most common neurodegenerative diseases caused by the loss of dopaminergic neurons in the substantia nigra pars compacta. Pharmacological therapies are valuable but suffer from two main drawbacks: side effects and loss of efficacy with disease progression. Surgical treatment is no better than drugs. Transplantation of embryonic mesencephalic tissue has emerged as a therapeutic alternative, but the unstable efficiency and the shortage of embryonic donors limit its clinical application. Recent advances in stem cell research inspire our hope that stem cell transplantation to replace degenerated neurons may be a promising therapy for Parkinson’s disease. There are three sources of stem cells currently in testing: embryonic stem cells, neural stem cells, and mesenchymal stem cells. The stem cell transplantation in the animal model of Parkinson’s disease proves that it is capable of relieving symptoms and restoring damaged brain function. Future stem cell research should focus not only on ameliorating the symptoms of Parkinson’s disease but also on neuroprotection or neurorescue that can favorably modify the natural course and slow the progression of the disease.     

Therapeutic modulation of growth factors and cytokines in regenerative medicine

Regeneration that takes place in the human body is limited throughout life. Therefore, when organs are irreparably damaged, they are usually replaced with an artificial device or donor organ. The term "regenerative medicine" covers the restoration or replacement of cells, tissues, and organs. Stem cells play a major role in regenerative medicine by providing the way to repopulate organs damaged by disease. Stem cells have the ability to self renew and to regenerate cells of diverse lineages within the tissue in which they reside. Stem cells could originate from embryos or adult tissues. Growth factors are proteins that may act locally or systemically to affect the growth of cells in several ways. Various cell activities, including division, are influenced by growth factors. Cytokines are a family of low-molecular-weight proteins that are produced by numerous cell types and are responsible for regulating the immune response, inflammation, tissue remodeling and cellular differentiation. Target cells of growth factors and cytokines are mesenchymal, epithelial and endothelial cells. These molecules frequently have overlapping activities and can act in an autocrine or paracrine fashion. A complex network of growth factors and cytokines guides cellular differentiation and regeneration in all organs and tissues. The aim of this paper is to review the role of growth factors and cytokines in different organs or systems and explore their therapeutic application in regenerative medicine. The role of stem cells combined with growth factors and cytokines in the regeneration of vascular and hematopoietic, neural, skeletal, pancreatic, periodontal, and mucosal tissue is reviewed. There is evidence that supports the use of growth factors and cytokines in the treatment of neurological diseases, diabetes, cardiovascular disease, periodontal disease, cancer and its complication, oral mucositis. After solving the ethical issues and establishing clear and reasonable regulations, regenerative medicine through stem cell application combined with specific growth factors and cytokines will have great potential in curing a variety of human diseases.     

细胞治疗帕金森病的研究进展

帕金森病（PD）是一种以黑质多巴胺能神经元丢失为主要病理特征的神经退行性疾病,其病因不清且发病 机制复杂。目前药物和手术治疗还难以根治PD。细胞治疗为PD治疗提供了新的策略,通过移植胎儿腹侧中脑组织 至患者纹状体,可使患者运动功能得到一定程度的恢复,证实细胞移植具有治疗PD的作用;干细胞,包括多能干细 胞、神经干细胞和间充质干细胞通过定向分化为多巴胺能神经元,为临床应用提供了可再生的细胞来源,进一步拓 展了细胞治疗的前景;诱导神经元治疗PD避免了建立体外干细胞库的高成本,有望实现神经元原位再生。就基于 不同细胞来源的PD细胞移植治疗研究进展进行综述,以期为再生医学治疗PD提供新的方向。