脊髓神经干细胞Niche的研究进展**

背景：脊髓损伤是临床上常见的骨科疾病,大量工作聚焦于神经干细胞治疗脊髓损伤的研究上,脊髓神经干细胞Niche对神经干细胞的作用成为了新的热点。 目的：综述脊髓神经干细胞Niche的相关研究进展。 方法：应用计算机检索PubMed 1980-01/2011-11期间的相关文章,检索词为“neural stem cells,niche/microenvironment,spinal cord”,并限定文章语言种类为English。同时计算机检索中国期刊全文数据库2003-01/2011-11 期间的相关文章,检索词为“神经干细胞,微环境,脊髓损伤”,并限定文章语言种类为中文。此外还手工查阅相关专著数部。 结果与结论：共检索到文献483篇,最终纳入31 篇。脊髓神经干细胞Niche为脊髓神经干细胞生存、自我更新以及分化提供了相对稳定的微环境,脊髓损伤后脊髓神经干细胞Niche的变化对脊髓神经干细胞的命运有着重要的影响。了解脊髓神经干细胞Niche中的神经干细胞、细胞组成、分子调节以及脊髓损伤后这一Niche中部分细胞的变化等的研究进展为应用神经干细胞治疗脊髓损伤提供了理论基础。      

嗅鞘细胞移植治疗脊髓损伤的研究进展

脊髓损伤是一种严重威胁人类健康的疾病，可致损伤平面以下的运动、感觉及植物神经功能障碍，其治疗一直是神经科学领域研究的难点与热点。众多研究表明，脊髓内细胞移植是具有里程碑意义的治疗策略，为严重脊髓损伤的治疗提供了新方法。其中，可用于移植的细胞主要有神经干细胞、雪旺细胞、少突胶质细胞、嗅鞘细胞等。所有这些细胞中嗅鞘细胞（olfactory ensheathing cells，OECs）的治疗效果最佳，它是一种特殊的大型神经胶质细胞，兼具中枢神经系统星形胶质细胞和外周雪旺细胞的双重特性，具有促进轴突再生和髓鞘化的能力，被许多学者认为是最理想的移植细胞，有可能在脊髓损伤的治疗上取得突破。本文就OECs移植治疗脊髓损伤的研究进展作综述如下。     

内源性神经干细胞治疗脊髓损伤

背景：脊髓损伤是一种严重的神经系统疾病,使患者的生活质量严重下降。近年来,随着医学的发展,内源性神经干细胞治疗脊髓损伤作为一种治疗策略被广泛关注。 目的：文章对内源性神经干细胞的活化、分化及治疗脊髓损伤的机制做一简要的综述。 方法：应用计算机检索万方数据库和PubMed数据库中2002-01/2011-03关于神经干细胞治疗脊髓损伤的文章,在标题和摘要中以“内源性神经干细胞;脊髓损伤;分化”或“Endogenous neural stem cells;Spinal cord injury; Differentiation”为检索词进行检索。选择文章内容与内源性神经干细胞治疗脊髓损伤相关,同一领域文献则选择近期发表或发表在权威杂志文章。初检得到340篇文献,根据纳入标准选择20篇文章进行综述。 结果与结论：内源性神经干细胞作为一种新型的治疗手段,它具有独特的优势,不仅避免了免疫排斥及伦理道德等方面的问题,而且在成年个体中也存在。大部分内源性神经干细胞分化成星形胶质细胞和少突胶质细胞,而不是神经元,但通过对信号传导通路的调控,可以是神经干细胞更多地分化为神经元细胞,从而发挥对脊髓损伤的治疗作用。     

神经干细胞与脊髓损伤的修复研究现状与展望

神经干细胞在哺乳动物中枢神经许多区域存在,已经从胚胎、胎儿和成人脑组织的不同部位,包 括海马、脑室/室管膜以及从皮质分离出来,能够在体外或体内扩增、分化为神经元和神经胶质。利用神经干 细胞进行细胞替代治疗和基因治疗有很好的临床应用前景,为治疗和修复脊髓损伤带来了希望。移植神经干 细胞或它们的分化产物至宿主脑,继而分化为内生干细胞是很多神经退行性变疾病的潜在治疗方法。     

施万细胞对植入半横断脊髓内的神经前体细胞存活及分化的影响

研究表明,神经前体细胞移植在修复中枢神经系统损伤及其退行性疾病方面具有潜在的应用价值.为了探讨施万细胞对神经前体细胞在损伤脊髓内存活及分化的影响,本实验将施万细胞与神经前体细胞联合植入大鼠脊髓损伤处,主要观察神经前体细胞的存活、迁移和分化情况.     

脐血源神经干细胞移植治疗陈旧性脊髓损伤

背景:随着医学的进步,脊髓损伤患者的预后未得到明显的改善,大部分患者常遗留严重的并发症。如今,许多实验室和临床研究成果已经提示细胞治疗具有巨大潜能,特别是脐血干细胞在神经系统疾病中的应用。目的:观察脐血源神经干细胞治疗陈旧性脊髓损伤的可行性和临床疗效。方法:无菌条件下采集新生儿脐血,在体外条件下分化成神经干细胞,制成细胞浓度为109 L-1的细胞悬液,经腰椎穿刺(L3-L4或L4-L5)注入蛛网膜下腔3 mL。移植前和移植后3个月对脊髓损伤患者行脊髓损伤神经学分类国际标准(ASIA)评分和膀胱残余尿量测定。结果与结论:脐血源神经干细胞移植后患者生命体征平稳,移植后3个月ASIA各项评分较前提高、膀胱残余尿量减少,差异有显著性意义(P0.05)。可见脐血源神经干细胞移植作为一种新的治疗方法,可以改善陈旧性脊髓损伤患者肢体功能,提高患者生活质量。     

内源性神经干细胞与骨髓间充质干细胞外泌体在脊髓损伤中的作用

脊髓损伤后神经细胞的再生在脊髓功能恢复中至关重要,脊髓中央管区的内源性神经干细胞在脊髓损伤后表现出干细胞特性,可以分化为神经元和胶质细胞;外泌体可以向内源性神经干细胞传递细胞因子、microRNAs、趋化因子等,促进内源性神经干细胞分化为神经元,对二者进行深入研究能为脊髓损伤的治疗寻求更优的治疗策略.     

异体骨髓间充质干细胞移植治疗大鼠脊髓损伤

背景:脊髓损伤的修复目前尚无良好的治疗手段,细胞移植能促进神经轴突再生及脊髓功能恢复,为治疗脊髓损伤提供了可能,但因脊髓损伤模型及移植方式不同,其治疗效果并不相同。目的:验证异体骨髓间充质干细胞移植对大鼠脊髓损伤的治疗作用。方法:全骨髓贴壁法分离大鼠骨髓间充质干细胞。健康SD大鼠随机分为3组,细胞移植组、对照组和假手术组。细胞移植组和对照组采用改良Allen重物打击法制造大鼠脊髓损伤模型,假手术组仅暴露脊髓。术后4周,每周进行运动功能评分ELISA检测脊髓损伤组织中脑源性神经营养因子、神经生长因子表达;免疫荧光染色检测脊髓组织中NF200和胶质纤维酸性蛋白表达。结果与结论:与对照组比较,细胞移植组大鼠运动功能明显改善,脊髓组织中脑源性神经营养因子、神经生长因子蛋白含量明显增高(P0.05);移植组大鼠脊髓囊腔较小,NF200表达明显增加,胶质纤维酸性蛋白表达减少。提示异体骨髓间充质干细胞移植能增加损伤脊髓神经生长因子含量,抑制胶质瘢痕形成,促进神经轴突再生,改善大鼠脊髓损伤后运动功能恢复。     

川芎嗪对大鼠脊髓损伤后铁代谢的影响北大核心

背景:铁代谢紊乱是导致脊髓损伤后神经细胞铁死亡的重要病理因素,不利于脊髓损伤修复。川芎嗪作为行气活血中药川芎的有效活性成分单体,被证实对脊髓损伤具有良好的抗炎、抗脂质过氧化反应以及神经保护作用,需进一步明确其促进脊髓损伤修复的作用机制。目的:研究川芎嗪对大鼠脊髓损伤后铁代谢的调节作用,探讨其改善脊髓损伤的相关机制。方法:将36只SD大鼠随机分为假手术组、模型组和川芎嗪组,每组12只;假手术组仅行椎板切除术,术后给予生理盐水腹腔注射;模型组和川芎嗪组制备脊髓损伤模型,术后分别给予生理盐水和川芎嗪腹腔注射,术后4周取材。采用BBB肢体运动功能评分评价大鼠肢体运动功能,尼氏染色观察神经元形态,普鲁士染色观察脊髓组织铁沉积,铁检测试剂盒检测脊髓组织铁含量,免疫组化检测铁蛋白重链1和铁蛋白轻链表达,Western blot检测铁蛋白重链1和铁蛋白轻链的蛋白表达量。结果与结论:(1)模型组和川芎嗪组大鼠各个时间点BBB评分显著低于假手术组(P <0.01),自术后第14天,川芎嗪组大鼠BBB评分显著高于模型组(P <0.01);(2)尼氏染色结果显示,假手术组神经元形态结构正常,模型组可见大量瘀血,神经元形态结构紊乱,川芎嗪组瘀血较少,神经元形态结构较模型组改善;(3)普鲁士染色结果显示,假手术组铁沉积较少,模型组和川芎嗪组铁沉积较多;普鲁士染色阳性平均吸光度值模型组和川芎嗪组显著大于假手术组(P <0.01),川芎嗪组显著小于模型组(P <0.01);(4)铁含量检测结果显示,模型组和川芎嗪组显著多于假手术组(P <0.01),川芎嗪组显著少于模型组(P <0.01);(5)免疫组化染色结果显示,铁蛋白重链1和铁蛋白轻链阳性表达平均吸光度值模型组和川芎嗪组显著小于假手术组(P <0.01),川芎嗪组显著大于模型组(P <0.01);(6)Western blot检测结果显示,铁蛋白重链1蛋白和铁蛋白轻链蛋白的相对表达量模型组和川芎嗪组显著少于假手术组(P <0.01),川芎嗪组显著多于模型组(P <0.01);(7)结果说明,川芎嗪通过调控铁蛋白重链1和铁蛋白轻链的表达而调节脊髓损伤后铁代谢紊乱,从而发挥神经保护作用,促进脊髓损伤大鼠肢体运动功能恢复。     

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.     

川芎嗪对大鼠急性脊髓损伤模型NF-kB及I-kBα表达的影响

 【摘要】 目的：观察川芎嗪对大鼠急性脊髓损伤模型损伤段NF-kB及I-kBα表达的影响。方法：SD大鼠110只,随机分正常对照组、单纯脊髓损伤组和川芎嗪处理组。采用改良ALLEN氏打击法建立大鼠急性脊髓损伤模型。采用改良Rivlin斜板实验、BBB(Basso,Beattie,Bresnahan)及CBS（Combine Behavior Score）评分对大鼠脊髓功能进行行为学评分。在建模后1h、3h、6h、12h、1d、3d、5d、7d、14d和21d获取损伤段脊髓标本,HE染色观察其组织病理变化;免疫组织化学染色检测NF-kB及I-kBα表达。结果：随着时间推移,术后斜板临界度数和BBB评分值均逐渐升高,CBS评分值逐渐降低,且术后7、14和21d川芎嗪处理组斜板临界角度数均较单纯脊髓损伤组高（P＜0.05）,术后5、7、14和21d实验组BBB评分值均较单纯脊髓损伤组高（P＜0.05）,而术后5、7、14和21d,川芎嗪处理组CBS评分值均较对照组低（P＜0.05）。术后1、3、5和7d,川芎嗪处理组NF-kB阳性细胞表达数较单纯脊髓损伤组低（P＜0.05）,I-kBα阳性细胞表达数较单纯脊髓损伤组高（P＜0.05）。结论：川芎嗪能够促进大鼠急性继发性损伤后脊髓组织中I-kBα的表达,抑制NF-kB的表达,从而起到促进脊髓功能恢复的作用。     

The pig model of chronic paraplegia: a challenge for experimental studies in spinal cord injury

The regenerative medicine techniques that are beginning to be applied to the nervous system have led to increased hope in the treatment of diseases that have been considered incurable and that require experimental models on which to test new therapeutic strategies. We present our experience with adult pigs (minipigs) that have undergone a traumatic spinal cord injury (SCI) experimental model, and that have been followed for 1 year. We describe the surgical aspects of our SCI model by acute compression and also describe protocols for daily care and rehabilitation that are necessary to maintain the paraplegic pigs in good health during the months following the injury. Furthermore, we provide in detail the main complications that arise with this experimental model and the treatments used to address these complications. Suitable housing conditions, daily rehabilitation and prevention of complications (i.e., taking the same care applied to patients following SCI) are essential for achieving the absence of mortality and long-term maintenance of the animals. We consider the model that is described here to be feasible and useful for preliminary testing of novel therapeutic strategies aimed at regeneration of the injured spinal cord in paraplegic patients.     

Targets and dimensions of social comparison among people with spinal cord injury and other health problems

The present research examined comparison targets and comparison dimensions among two Spanish samples of individuals facing serious illnesses and diseases. In Study 1, 90 older patients (mean age 66.36) with various age‐related diseases, particularly cardiovascular diseases and diabetes, indicated that they compared themselves most often with others with the same disease, next with others with another disease and least with people without health problems. They compared themselves more often on their mental state, symptoms and physical activities than on their social activities. Social comparison orientation (SCO) as an individual difference characteristic was associated with more frequent comparisons with particularly similar targets, and with more frequent comparisons of one's symptoms and physical activities. Neuroticism was correlated only with more comparisons of one's symptoms. Study 2 was conducted in a sample of 70 relatively young patients (mean age 43.97) with spinal cord injury (SCI). Overall, they compared themselves more often with others than the participants in Study 1, and they compared themselves to a similar extent with people with SCI as with people with another disease and with people without health problems. While they felt on average better off than people with other diseases and other people with SCI, people with SCI felt on average worse off than people without health problems. They compared themselves more often on physical activities than on any other dimension. Higher levels of stress and uncertainty were associated with more frequent comparisons with people without SCI, and with more frequent comparisons of one's mental state, one's symptoms and one's future perspectives. The discussion focuses on the theoretical relevance of the results for social comparison theory, and on the practical relevance of the findings for interventions.     

川芎嗪对肾间质纤维化中TGF-β1/miR-29表达的影响

目的:观察川芎嗪(tetramethylpyrazine,TMP)对单侧输尿管结扎(unilateral ureteral obstruction,UUO)大鼠模型肾间质纤维化(renal interstitial fibrosis,RIF)、间质损伤及TGF-β1/miR-29表达的影响.方法:50只雄性Wistar大鼠随机分为5组:正常对照组(Ctrl组)、假手术组(Sham组)、模型组(UUO组)、缬沙坦组(VAN组)和TMP组各10只.经相应处理后,通过HE,Masson染色观察肾组织的病理学表现;同时采用SP免疫组织化学法检测各组病变组织中TGF-β1的表达情况;最后采用RT-PCR技术比较各组TGF-β1,miR-29基因的表达.结果:HE染色结果显示Ctrl组、Sham组、UUO组、VAN组及TMP组的肾间质损伤评分分别为0.27±0.10,0.30±0.12,8.79±1.03,6.23±0.81及4.57±0.74.Masson染色胶原半定量分析结果显示Ctrl组、Sham组、UUO组、VAN组及TMP组的评分分别为0.21±0.03,0.23±0.06,2.49±0.33,1.63±0.07及1.32±0.04.SP免疫组织化学染色显示模型组TGF-β1的蛋白表达高于对照组;而缬沙坦和TMP可部分逆转TGF-β1蛋白的表达,且TMP的效果优于缬沙坦.RT-PCR结果显示模型组的TGF-β1 mRNA表达增高、miR-29 mRNA表达降低.TMP组和缬沙坦组TGF-β1 mRNA表达明显低于模型组,而miR-29 mRNA表达则明显高于模型组;且TMP 组TGF-β1 mRNA表达高于缬沙坦组.结论:缬沙坦和TMP可明显减轻UUO致RIF中肾组织学损伤,且TMP的疗效优于缬沙坦.此外TMP还可抑制TGF-β1而促进miR-29的表达.     

Activity and interaction of trimethoprim and sulphamethoxazole against Escherichia coli.

The activity of trimethoprim (TMP) and sulphamethoxazole (SMX), alone and in combination, against a sensitive strain of Escherichia coli was investigated in turbidimetric systems. In a static system in which the conditions of exposure of bacteria to drug resembled those of conventional minimum inhibitory concentration (MIC) titrations, both TMP and SMX exhibited antibacterial activity at concentrations well below the conventionally determined MIC, but regrowth occured at these concentrations during the overnight incubation period due to the emergence of adaptively resistant bacteria. Tests of combined drug action in the static turbidimetric system revealed even more synergic interaction than was apparent in conventional MIC tests. It is suggested that an important component of overall synergic interaction is the mutual suppression of adaptive "resistance" to the other agent. Studies in an in vitro model which simulates the hydrokinetic features of the urinary bladder showed that concentrations of TMP and SMX below the conventionally determined MIC inhibited the growth even of extremely dense bacterial populations so long as the concentration of drug was maintained. The response of cultures exposed to combinations of TMP and SMX in this system was so dominated by the effect of TMP that no synergic interaction with SMX was noted at concentrations of the drugs which are achievable in urine.     

Lipoproteins and free plasma catecholamines in spinal cord injured men with different injury levels.

Persons with spinal cord injury (SCI) are especially prone to atherogenesis. This is partly explained by an unfavourable lipoprotein profile in these individuals. The impairment of the sympathetic nervous system, and the fact that SCI subjects are subject to extreme physical inactivity, may have an influence on their lipid profile and lipoprotein(a) concentration. We made a detailed investigation of the lipid profile as well as serum levels of adrenaline and noradrenaline in 80 men with SCI ranging from tetraplegia to low paraplegia and in 16 control subjects. The lipid profile of tetraplegics was characterized by elevated very low-density lipoprotein cholesterol and triglyceride levels and reduced high-density lipoprotein levels. In contrast, paraplegics had significantly higher low-density lipoprotein and total cholesterol levels. Tetraplegics had lower and the low-lesion paraplegics had higher adrenaline and noradrenaline levels than the high-lesion paraplegics and the control subjects. High-lesion SCI subjects also showed an extreme reduction in VO2max. The lipoprotein profile was dependent on the injury level and serum catecholamine concentrations. The lower the noradrenaline values, the lower the high-density lipoprotein cholesterol. The low-density lipoprotein also correlated to catecholamines and particularly adrenaline values. Despite the correlation between lipoprotein(a) and adrenaline, no significant differences in lipoprotein(a) were found within SCI individuals as well as between SCI individuals and control subjects, indicating the predominantly genetic determination of lipoprotein(a) and thus the cardiovascular risk. Different serum catecholamine levels due to impairment of sympathetic nervous system and VO2max levels were observed in SCI subjects. This was associated with a higher lipid risk profile for cardiovascular diseases; however, the risk profile is dependent on the lesion level.     

New onset focal weakness in children with Down syndrome

New onset focal weakness is relatively common in patients with Down syndrome (DS), and has broad differential diagnosis. Ten cases of new onset focal weakness in patients with DS were encountered or are currently being followed in two DS clinics, with a combined population of patients of approximately 850, for a clinic population prevalence of 1.2%. The median age at presentation was 4 years old (range 1 month-44 years). The causes of new onset focal weakness were: stroke from Moyamoya disease (two patients); stroke from vaso occlusive disease (one patient); stroke from venus sinus thrombosis (one patient); traumatic subdural hematoma (one patient); brain abscess (one patient); spinal cord injury (SCI) from cervical spinal stenosis (two patients); SCI from atlantoaxial instability (AAI) (one patient); and brachial plexus injury (one patient). Of the 10 patients with focal weakness, 8 had potentially treatable conditions, and 5 had surgery. The differential diagnosis of new onset focal weakness in DS is broad, with diseases reported involving all levels of the nervous system from brain to muscle. For some diagnoses, expeditious diagnosis may improve outcome.     

Cardiac involvement in systemic autoimmune diseases

The heart and the vascular system are frequent and characteristic targets of several systemic autoimmune diseases, in particular Systemic Lupus Erythematosus (SLE), Rheumatoid Arthritis (RA) and Systemic Sclerosis (SSc). In this chapter we review the classic cardiac abnormalities and the more recent data about cardiovascular involvement as part of a major disease complication determining a substantial morbidity and mortality. In addition to the classic cardiac abnormalities involving the heart structures, acute and chronic ischemic heart disease and cerebrovascular accidents are threatening clinical manifestations of SLE and RA associated to an early accelerated atherosclerosis. Immune-mediated inflammation is now recognized as an important factor involved in the pathogenesis of atherosclerosis. Ongoing clinical studies are being devised to find specific risk factors associated with systemic autoimmune diseases and/or treatment regimens. Hopefully, prophylactic measures should be available within the next few years.     

Early response of endogenous adult neural progenitor cells to acute spinal cord injury in mice

Adult neural progenitor cells (NPCs) are an attractive source for functional replacement in neurodegenerative diseases and traumatic injury to the central nervous system (CNS). It has been shown that transplantation of neural stem cells or NPCs into the lesioned region partially restores CNS function. However, the capacity of endogenous NPCs in replacement of neuronal cell loss and functional recovery of spinal cord injury (SCI) is apparently poor. Furthermore, the temporal and spatial response of endogenous adult NPCs to SCI remains largely undefined. To this end, we have analyzed the early organization, distribution, and potential function of NPCs in response to SCI, using nestin enhancer (promoter) controlled LacZ reporter transgenic mice. We showed that there was an increase of NPC proliferation, migration, and neurogenesis in adult spinal cord after traumatic compression SCI. The proliferation of NPCs detected by 5-bromodeoxyuridine incorporation and LacZ staining was restricted to the ependymal zone (EZ) of the central canal. During acute SCI, NPCs in the EZ of the central canal migrated vigorously toward the dorsal direction, where the compression lesion is generated. The optimal NPC migration occurred in the adjacent region close to the epicenter. More significantly, there was an increased de novo neurogenesis from NPCs 24 hours after SCI. The enhanced proliferation, migration, and neurogenesis of (from) endogenous NPCs in the adult spinal cord in response to SCI suggest a potential role for NPCs in attempting to restore SCI-mediated neuronal dysfunction.