The neurobiology of cell transplantation in Parkinson's disease

Over the past decade, neural grafting has emerged as a new treatment option for Parkinson's disease. When performed successfully, grafts of human embryonic neural tissue can give rise to major symptomatic relief in patients. However, a recent report on a double-blind placebo control study, which received worldwide attention, described less pronounced beneficial effects of the grafts, and found them to be significant only in patients younger than 60 years of age. Moreover, a subgroup of patients developed disabling dyskinesias as a result of the surgery. These findings, and great logistical problems in coordinating the harvesting of sufficient amounts of suitable human embryonic donor tissue with the transplantation surgery, have led the scientific community to question whether cell transplantation really has a future as a therapy for Parkinson's disease. In this review, we argue that the future of neural transplantation for Parkinson's disease is still bright. We relate clinical findings to observations made in experimental animals grafted with embryonic neural tissue and seek explanations for the variability in outcome seen in the clinical trials. We also briefly discuss alternative sources of donor tissue that may be applied in future clinical trials, and mention what features of cells may be crucial for them to be suitable as donor tissue for transplantation in Parkinson's disease.     

The interhemispheric connections of the striatum: Implications for Parkinson's disease and drug-induced dyskinesias

Parkinson's disease (PD) is characterized by loss of nigrostriatal neurons and depletion of dopamine. This pathological feature leads to alterations to basal ganglia circuitry and subsequent motor disability. Pharmacological dopamine replacement therapy with medications such as levodopa ameliorates the symptoms of PD but can lead to motor complications known as drug-induced dyskinesias. We have recently shown that clinically hemiparkinsonian rhesus monkeys do not develop levodopa-induced dyskinesias despite chronic intermittent exposure and significant unilateral loss of nigrostriatal neurons and dopamine. It is currently unclear what mechanisms prevent the onset of dyskinesias in these animals. Based on our study and results from previous lesioning studies in both the rat and monkey models of PD, we hypothesize that one potential mechanism that may prevent the genesis of dyskinesias in these animals is interhemispheric neuromodulation. Two potential interhemispheric connections that may modulate dyskinesias are the interhemispheric nigrostriatal and corticostriatal pathways. Few investigators have examined the interhemispheric nigrostriatal and corticostriatal connections and the functional role they may play in drug-induced dyskinesias in PD. Therefore, in the following review, we assess the neuroanatomical, electrophysiological and behavioral properties of these interhemispheric connections. Future studies evaluating these interhemispheric striatal pathways and the pathophysiological changes that occur to these pathways in the dyskinetic state are warranted to further develop treatments that prevent or mitigate drug-induced dyskinesias in PD.     

神经干细胞移植治疗小鼠机械性脑损伤的实验研究

目的探讨神经干细胞移植后的体内存活、增殖与分化,及其对小鼠机械性脑损伤的治疗作用。方法运用牙科钻制作小鼠运动区皮质机械性损伤模型。48只清洁级昆明小鼠,雌雄不拘,体质量为18～20g,按体质量编号随机分为4组:神经干细胞移植组(损伤后原位移植经鉴定确认的原代培养的小鼠神经干细胞)、3T3移植组(损伤后原位移植3T3细胞)、单纯损伤组(损伤后不行神经干细胞移植)和空白对照组(仅施行麻醉),每组12只小鼠。于伤后第3天进行行为学检测;第10、30天行损伤区脑组织nestin及NF200免疫荧光染色,观察神经干细胞生长、分化情况。结果损伤后,获得原代培养的神经干细胞在移植早期贴附于损伤区域且向周边组织呈浸润生长;移植后期Hoechst33342及NF200染色显示损伤区附近可见分化形成的神经元。单纯损伤组小鼠出现偏瘫症状;而神经干细胞移植组小鼠植入神经干细胞后则症状减轻,运动功能明显改善,与其他各组相比差异有显著性意义(P<0.001)。结论神经干细胞移植能够改善小鼠机械性脑损伤后的神经功能状态。     

骨髓源神经干细胞移植治疗中枢神经系统损伤的蛋白质组学研究

目的 利用同位素标记相对和绝对定量(iTRAQ)技术以及串联质谱技术分析中枢神经系统损伤患者干细胞移植前术后脑脊液蛋白质表达变化情况.方法 收集正常成人以及中枢神经系统损伤患者移植前后脑脊液,组内等量混合后利用高效液相色谱柱去除高丰度蛋白,样本经iTRAQ试剂标记后利用二维色谱分离,经串联质谱鉴定并相对定量.结果 质谱得到的多肽片段经谱库搜索鉴定的蛋白共59个,其中患者移植前脑脊液与正常对照组脑脊液存在差异的蛋白质有13个,5个呈高表达,8个呈低表达.患者移植后脑脊液有7种蛋白质与正常对照组表达无差异.结论 蛋白质组学研究方法可以用来寻找神经系统损伤标志物,为神经系统损伤以及修复的机制研究提供基础.     

脐带间充质干细胞移植治疗帕金森病8例**

背景：中枢神经系统的神经细胞是一种终末细胞,任何病理过程导致的神经元丢失都将是一个不可逆过程。目的：观察间充质干细胞移植治疗帕金森病患者神经功能的效果。方法：选择2010-08/11上海455医院干细胞移植中心收治的帕金森病患者8例,男4例,女4例,年龄50~78岁。所有患者均住院治疗,自第2周起应用脐带间充质干细胞进行颈动脉穿刺移植治疗,采用帕金森病统一评分量表(Unified Parkinson's Disease Rating Scale,UPDRS)对患者移植前后神经功能进行评定,分值越高表示神经功能缺损越严重。结果与结论：8例患者均进入结果分析。与移植前相比,8例患者移植后1个月帕金森病统一评分量表分值均明显降低(P < 0.05),主要集中在对震颤、强直的改善,而运动迟缓、姿势不稳等临床症状无明显改善。8例患者均未出现移植物抗宿主病。提示脐带间充质干细胞移植可以一定程度地改善帕金森病患者的临床症状,提高患者生活质量。     

PET imaging of implanted human retinal pigment epithelial cells in the MPTP-induced primate model of Parkinson's disease

Human retinal pigment epithelial (hRPE) cells produce L-dopa, are easily harvested and expanded in culture, and, attached to microcarriers, can survive in the brain without immunosuppression. Studies in rats, primates, and parkinsonian patients have demonstrated that striatally implanted hRPE cells attached to gelatin microcarriers (RPE-GM) are able to improve parkinsonian symptoms and are well tolerated for extended periods. In moderately to severely impaired monkeys with bilateral 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine hydrochloride (MPTP)-induced parkinsonism receiving a unilateral RPE-GM implant in the putamen, there was a 39% improvement in clinical scores over the first 2 months post-implant. Positron emission tomography (PET) with [18F]fluoro-L-dopa (FDOPA) showed increased accumulation in the implanted putamen and a concomitant decrease in [11C]raclopride binding in the same area, suggesting increased dopamine release compared to the contralateral putamen. We report the first in vivo visualization of hRPE cells and their effects, implicating a dopaminergic mechanism of action.     

Retinal pigment epithelial cell transplantation could provide trophic support in Parkinson's disease: results from an in vitro model system

Transplantation of retinal pigment epithelial (RPE) cells in the basal ganglia could provide a novel cell-based therapy for Parkinson's disease by providing a constant source of dopamine replacement via the melanin synthetic pathway enzyme tyrosinase. We now demonstrate that human RPE cells also produce a neurotrophic effect on primary cultures of rat striatal (enkephalinergic) and mesencephalic (dopaminergic) neurons. Differentiation of RPE cells to a pigmented monolayer using a Ca(++)-switch protocol increased the potency of the neurotrophic effect on dopaminergic neurons. Conditioned medium derived from differentiated RPE cells increased neurite outgrowth in dopaminergic neurons by 125% compared to 25% for undifferentiated RPE cells. The neurotrophic effect was not due to tyrosinase activity. Differentiation of RPE cells doubled the production of pigment-derived epithelial factor (PEDF). However, PEDF accounted for only a portion of the neurotrophic effect as determined by depletion experiments and dose-response comparisons with purified PEDF, indicating that differentiation increased the production of other trophic factors as well. Conditioned medium from differentiated RPE cells also provided a neurotrophic effect on a subset of enkephalinergic striatal neurons increasing neurite outgrowth by 78%. Survival of enkephalinergic neurons in vitro was increased by RPE conditioned medium. In untreated cultures the number of enkephalinergic neurons declined 62% over a 2-week period compared to a 29% decline in RPE-treated cultures. These results indicate that transplantation RPE cells could potentially provide a dual benefit in Parkinson's disease producing both dopamine and neurotrophic support of the basal ganglia.     

骨髓基质细胞移植治疗帕金森病河猴的实验研究

目的 探讨以骨髓基质细胞(BMSCs)为供体移植治疗帕金森病(PD)模型恒河猴的可行性.方法 应用立体定向手术毁损单侧黑质建立恒河猴PD模型,采用加拿大评分和单光子发射计算机断层成像术(SPECT)分别观察恒河猴行为学和大脑黑质多巴胺转运蛋白(DAT)的变化,免疫荧光双标染色检测恒河猴黑质移植侧和正常侧BMSCs的分化状态.结果 移植BMSCs后恒河猴的PD综合征症状逐渐加重;SPECT检测显示恒河猴移植BMSCs前后黑质双侧DAT无明显变化,但免疫荧光显示移植后BMSCs分化为多巴胺(DA)能神经元的比例高达25%.结论 BMSCs无法作为有效的移植供体治疗PD,其可行性尚需进一步研究.     

壳聚糖作为中枢神经系统支架材料的可行性研究

目的探索壳聚糖作为中枢神经系统组织工程支架材料的可行性。方法选择孕14～16dWistar大鼠剖宫取胎鼠脑进行分离、培养,经巢蛋白、胶原纤维酸性蛋白、特异性烯醇化酶和半乳糖脑苷酯免疫细胞化学染色鉴定获得神经干细胞,种植于壳聚糖膜和明胶膜表面培养,然后行巢蛋白免疫细胞化学染色,观察神经干细胞在壳聚糖膜和明胶膜表面的贴附、生长和分化状态,以及壳聚糖、明胶的降解速度。结果从胎鼠大脑分离获得的神经干细胞,巢蛋白染色呈阳性反应,可分化形成神经元和胶质细胞,分化细胞分别呈胶原纤维酸性蛋白、特异性烯醇化酶和半乳糖脑苷酯染色阳性反应。神经干细胞接种后12h即贴附于壳聚糖膜表面,24h壳聚糖膜和明胶膜均贴附牢固;48h明胶膜表面神经球周围首先出现带突起的分化细胞,壳聚糖膜迟至生长第3天才出现。神经干细胞接种生长后第3天,壳聚糖膜部分降解,明胶膜完全降解;第4天膜表面长满分化细胞;第5、6天壳聚糖膜大部分降解,分化细胞部分死亡。结论壳聚糖与神经干细胞生物相容,具有促细胞贴附和分化作用,由于机械性能差,不宜作为中枢神经组织工程的结构性生物支架材料,但可以单独或者联合促贴附物明胶作为促神经干细胞贴附和分化的支架表面修饰剂。     

干细胞移植治疗脑胶质瘤的研究进展

尽管脑胶质瘤的治疗取得不断的进步，但其致残率和死亡率仍很高，其难以根除的主要原因是肿瘤细胞对脑组织的高度浸润性。传统的外科手术辅助放疗、化疗方法对正常神经组织的破坏及副作用很大，如放射性坏死、认知障碍和脑白质病等。近几年随着干细胞技术的兴起，利用干细胞作为载体的脑胶质瘤基因治疗受到广泛关注，该治疗方法的优势在于既能除去肿瘤细胞又有组织修复功能。本就干细胞治疗神经胶质瘤的细胞来源、肿瘤趋向性、治疗机理及体内监测等方面的现状及进展进行简要回顾和展望。[第一段]     

Stem cell challenges in the treatment of neurodegenerative disease

Neurodegenerative diseases result from the gradual and progressive loss of neural cells and lead to nervous system dysfunction. The rapidly advancing stem cell field is providing attractive alternative options for fighting these diseases. Results have provided proof of principle that cell replacement can work in humans with Parkinson's disease (PD). However, three clinical studies of cell transplantation were published that found no net benefit, while patients in two of the studies developed dyskinesias that persisted despite reductions in treatment. Induced pluripotent stem cells (iPSC) have major potential advantages because patient-specific neuroblasts are suitable for transplantation, avoid immune reactions, and can be produced without the use of human ES cells (hESC). Although iPSCs have not been successfully used in clinical trials for PD, patients with amyotrophic lateral sclerosis (ALS) were treated with autologous stem cells and, though they had some degree of decline one year after treatment, they were still improved compared with the preoperative period or without any drug therapy. In addition, neural stem cells (NSCs), via brain-derived neurotrophic factor (BDNF), have been shown to ameliorate complex behavioral deficits associated with widespread Alzheimer's disease (AD) pathology in a transgenic mouse model of AD. So far, the FDA lists 18 clinical trials treating multiple sclerosis (MS), but most are in preliminary stages. This article serves as an overview of recent studies in stem cell and regenerative approaches to the above chronic neurodegenerative disorders. There are still many obstacles to the use of stem cells as a cure for neurodegenerative disease, especially because we still don't fully understand the true mechanisms of these diseases. However, there is hope in the potential of stem cells to help us learn and understand a great deal more about the mechanisms underlying these devastating neurodegenerative diseases.     

脑损伤的干细胞移植治疗研究进展

外伤性脑损伤(traumatic brain injury,TBI)是世界性的多发性疾病,也是死亡率和致残率最高的疾病之一.TBI后生存患者常残留有运动、认知及社会交流障碍,导致患者、家属及社会受到破坏性影响~([1]).     

Cell transplantation for the treatment of Parkinson's disease

Cell transplantation is an experimental therapy for Parkinson's disease (PD) and other movement disorders. Several open-label research trials have shown clinically meaningful improvement in parkinsonian signs and symptoms after striatal transplantation of allogeneic fetal ventral mesencephalic (FVM) tissue. However, ethical concerns, variability in surgical techniques, and reports of unusual late complications in a few patients in a clinical trial have limited the use of allogeneic FVM tissue to a few research centers. Research into alternative cell sources such as porcine FVM and allogeneic retinal pigment epithelial cells has shown promising results in preclinical trials, and they are currently being tested in clinical trials. Novel strategies to improve cell survival and to avoid immune rejection of transplants show promising results in preclinical trials. This article focuses on these recent advances and compares the potential clinical utility of these emerging cell therapies for the treatment of advanced PD.     

手足口病患儿合并中枢神经系统损害临床分析

目的：探讨手足口病患儿合并中枢神经系统损害的临床特点及治疗方法。方法选取合并中枢神经系统损害的手足口病患儿137例,随机分为2组。回顾分析所有患者的临床特点、试验时间、检查结果,并进行统计。2组患儿均实施综合治疗,在此基础上,对照组给予胞二磷胆碱静滴,观察组给予神经节苷脂静滴。对2组患儿神经系统好转时间、发热缓解时间及痊愈时间进行统计。于治疗10 d时测定2组患儿神经元特异性烯醇化酶水平,评价2组患儿治疗效果。结果发热、皮疹、易惊是手足口病患儿合并中枢神经系统损害最为常见的临床表现;脑脊液细胞数升高是实验室检查中最常见的异常。观察组患者神经系统好转时间、发热缓解时间、痊愈时间及神经元特异性烯醇化酶水平均明显低于对照组。结论手足口病患儿合并中枢神经系统损害的临床表现缺乏特异性,治疗时应在综合治疗的基础上加用神经节苷脂静脉注射。     

Stem cell transplantation for treating Parkinson's disease Literature analysis based on the Web of Science

OBJECTIVE:To identify global research trends of stem cell transplantation for treating Parkinson’s disease using a bibliometric analysis of the Web of Science.DATA RETRIEVAL:We performed a bibliometric analysis of data retrievals for stem cell transplantation for treating Parkinson’s disease from 2002 to 2011 using the Web of Science.SELECTION CRITERIA:Inclusion criteria:(a) peer-reviewed articles on stem cell transplantation for treating Parkinson’s disease which were published and indexed in the Web of Science;(b) type of articles:original research articles,reviews,meeting abstracts,proceedings papers,book chapters,editorial material and news items;(c) year of publication:2002-2011.Exclusion criteria:(a) articles that required manual searching or telephone access;(b) we excluded documents that were not published in the public domain;(c) we excluded a number of corrected papers from the total number of articles.MAIN OUTCOME MEASURES:(1) Type of literature;(2) annual publication output;(3) distribution according to journals;(4) distribution according to subject areas;(5) distribution according to country;(6) distribution according to institution;(7) comparison of countries that published the most papers on stem cell transplantation from different cell sources for treating Parkinson’s disease;(8) comparison of institutions that published the most papers on stem cell transplantation from different cell sources for treating Parkinson’s disease in the Web of Science from 2002 to 2011;(9) comparison of studies on stem cell transplantation from different cell sources for treating Parkinson’s disease RESULTS:In total,1 062 studies on stem cell transplantation for treating Parkinson’s disease appeared in the Web of Science from 2002 to 2011,almost one third of which were from American authors and institutes.The number of studies on stem cell transplantation for treating Parkinson’s disease had gradually increased over the past 10 years.Papers on stem cell transplantation for treating Parkinson’s disease appeared in journals such as Stem Cells and Experimental Neurology.Although the United States published more articles addressing neural stem cell and embryonic stem cell transplantation for treating Parkinson’s disease,China ranked first for articles published on bone marrow mesenchymal stem cell transplantation for treating Parkinson’s disease.CONCLUSION:From our analysis of the literature and research trends,we found that stem cell transplantation for treating Parkinson’s disease may offer further benefits in regenerative medicine.     

A novel approach to neural transplantation in Parkinson's disease: Use of polymer-encapsulated cell therapy

Transplantation of dopaminergic neurons derived from fetal or adrenal tissue into the striatum is a potentially useful treatment for Parkinson's disease (PD). Although initially promising, recent clinical studies using adrenal autografts have demonstrated limited efficacy. The use of human fetal cells, despite promising preliminary results, is complicated by tissue availability and ethical concerns. An attractive alternative is based on encapsulating dopamine-producing cells into polymer capsules prior to transplantation. Polymer capsules can be fabricated to surround the cells with a semi-permeable and immunoprotective barrier. The semi-permeable membrane allows nutrients to enter the capsule, so the encapsulated cells will survive and function, and dopamine and other low molecular weight constituents to diffuse out into the host tissue. Thus, the technique allows use of unmatched human tissue (allografts), or even animal tissue (xenografts) without immunosuppression of the recipient. Cell-loaded polymer capsules can also be retrieved if necessary or desired. The demonstration that striatal implants of encapsulated dopamine-producing cells promote behavioral recovery in rodent and primate models of PD further suggests that cellular encapsulation may be a useful strategy for ameliorating the behavioral consequences of PD.     

Clinical criteria for the switch of treatment strategies in Parkinson's disease

Along the years the treatment of Parkinson's disease with L-dopa has revealed unfavorable effects in general after 5–10 years. This has led to the present criteria for treatment of de novo patients that mainly relay on the age, the general strategy being to delay the use of L-dopa as long as possible. However, this practical approach lacks a scientific basis. In a retrospective study data of 155 patients with Parkinson's disease were analyzed with the goal of finding a clinical marker for the critical time point when L-dopa needs to be administrated. The clinical stage of the patients was assessed using the Hoehn and Yahr (H&Y) scale and the severity of the symptoms was measured using the UPDRS score. The results show that there was no relationship between the age of the patients and the therapy (L-dopa vs. no L-dopa) with regard to the clinical outcome. A significant interaction was found however, between the clinical stage (H&Y) and the therapy. Further analysis of this interaction showed that in the H&Y Stages 1–2.5 the UPDRS scores were lower in the patient groups treated without L-dopa. Remarkably, in the H&Y stages 3 and higher the UPDRS scores were lower in the patient groups treated with L-dopa. These results suggest that the clinical stage of the disease (H&Y) might be a better criterion than the age for the time point when L-dopa needs to be administered in de novo patients.     

The potential use of adult stem cells for the treatment of multiple sclerosis and other neurodegenerative disorders

No specific treatment exists for patients with multiple sclerosis (MS) who fail to respond to conventional immunosuppressive and immunomodulating modalities. Furthermore, no method is available for regeneration of existing defect in the central nervous system (CNS). The ultimate goals of MS treatment, similarly to other autoimmune diseases, are twofold: first, to eliminate self-reactive lymphocytes and to prevent de novo development of self-reactivity by induction of self-tolerance. Second, attempting regeneration and repair of existing damage. In the case of MS, there is a need to stop the ongoing process of inflammation against the CNS by self-reactive lymphocytes thus facilitating spontaneous re-myelinization while in parallel attempt to recover existing neurological deficits caused by the autoimmune process resulting in demyelinization. Cell therapy stands out as the most rationale approach for neurological regeneration. In the absence of clinically applicable approaches involving the use of embryonic stem cells, we are investigating the feasibility and efficacy of enriched autologous mesenchymal stromal cells (MSC) injected intrathecally and intravenously to induce in situ immunomodulation and neuroprotection and possibly facilitate repair of the CNS in patients with MS and other neurodegenerative disorders. Our preclinical results suggest that bone marrow cells may provide a source of stem cells with a potential for migration into inflamed CNS and differentiate into cells expressing neuronal and glial cell markers. Based on the preclinical data, we are currently evaluating the safety of a similar therapeutic approach in a small group of patients with MS and other neurodegenerative diseases.     

自体分选造血干细胞和异体脐带间充质干细胞移植治疗神经系统变性疾病

背景：将自体分选造血干细胞和异体脐带间充质干细胞技术应用于临床,试图寻找一种新的治疗神经系统变性疾病的可行方法。 目的：探讨自体分选CD34+造血干细胞和异体脐带间充质干细胞治疗神经系统变性病的可行性。 方法：入选神经系统变性病患者21例,其中运动神经元病15例,脊髓小脑共济失调6例。取4 mL的脐带间充质干细胞或自体分选干细胞液经腰穿注射到患者蛛网膜下腔,每次注射的细胞数1.0×107。于干细胞治疗后3个月进行评分。 结果与结论：15例运动神经元病患者,治疗总有效率为80%,治疗前后的脊髓侧索硬化功能分级量表和自我评估问卷评分差异有显著性意义(P < 0.05);6例脊髓小脑共济失调患者,按ICARS评分,4例病情等级下降,治疗总有效率为77%。21例中4例有轻度低颅压性头痛(腰穿后),14例采用脐带间充质干细胞治疗的患者中2例在治疗后2 h出现短暂发热,其余患者治疗后未见明显不良反应。结果初步表明自体分选造血干细胞和异体脐带间充质干细胞治疗神经系统变性病临床疗效肯定,安全可行。