老年痴呆症

2015-10-31 06:42阿尔茨海默病的防治策略研究进展
中国学术期刊文摘 2015年12期
关键词:老年痴呆阿尔茨海默病细胞凋亡

阿尔茨海默病的防治策略研究进展

倪嘉缵,陈平,刘琼,郑易之,何晓阳,宋国丽,应明,续旭

(深圳大学生命科学学院 深圳市海洋生物资源与生态环境重点实验室 深圳市微生物基因工程重点实验室,深圳 518060)

Clinical-diagnosis of Alzheimers-disease - report of the nincds-adrda work group under the auspices of department-of-health-and-human-services task-force on Alzheimers-disease

McKhann G; Drachman D; Folstein M; et al.

Alzheimers-disease - initial report of the purification and characterization of a novel cerebrovascular amyloid protein

Glenner GG; Wong CW

Amyloid plaque core protein in Alzheimer-disease and down syndrome

Masters CL; Simms G; Weinman NA; et al.

The precursor of Alzheimers-disease amyloid-a4 protein resembles a cell-surface receptor

Kang J; Lemaire HG; Unterbeck A; et al.

糖尿病脑病与老年性痴呆

盛树力

老年痴呆症

·编者按·

阿尔茨海默病(Alzheimer’s disease,AD)俗称老年痴呆症,是常见的中枢神经系统退行性疾病,主要临床表现为进行性记忆和认知功能障碍,主要的病理特征为淀粉样蛋白(β-amyloid,Aβ)沉积形成的老年斑、tau蛋白过度磷酸化导致的神经纤维缠结(neurofibrillary tangles,NFTs)以及神经元丢失和突触损伤.

中国是世界上老年人口基数及阿尔茨海默病患者基数最大的国家,也是老龄化速度最快的国家.全国老龄办发布的《中国人口老龄化发展趋势预测研究报告》显示,到2020年,老年人口将达到2.48亿,老龄化水平将达到17.17%;2051年,中国老年人口规模将达到峰值4.37亿,老龄化水平达到31%左右.而阿尔茨海默病发病率则随年龄增大急增,已成为威胁老年人生命健康的主要疾病,给个人和社会带来极大负担,这一疾病的研究,成为很多研究者关切的重点.

阿尔茨海默病的病因复杂,总体上是环境、生活习惯和遗传等多因素综合作用的结果.已经提出的学说包括Aβ沉积学说、Tau蛋白异常磷酸化学说、氧化应激学说、炎症反应学说等.其中,“Aβ学说”和“tau学说”是两大主流学说,Aβ学说认为阿尔茨海默病发病始于Aβ的产生和清除失去平衡,可溶性和非可溶性Aβ肽在脑内蓄积,导致神经元毒性.tau学说认为tau蛋白过度磷酸化,使得神经元细胞骨架发生改变,引发神经原纤维缠结.在大量研究“Aβ”和“tau”各自独立致阿尔茨海默病病因学说的同时,Aβ蛋白和tau蛋白之间的主从关系和相互作用也越来越受到研究者关注.

目前,治疗阿尔茨海默病主要以Aβ和tau为靶点.其中以Aβ为主要治疗靶点的研究包括:β分泌酶抑制剂、γ分泌酶抑制剂、免疫治疗、静脉注射免疫球蛋白治疗和抑制Aβ聚集.以tau为治疗靶点的研究包括:多种酶参与tau蛋白磷酸化,糖原合成酶激酶-3以及相关的主动免疫和被动免疫治疗.其他防治还包括干细胞治疗、以线粒体为靶点的防治策略等.临床上主要采用胆碱酯酶抑制剂、乙酰胆碱受体激动剂、谷氨酸受体拮抗剂和脑代谢激活剂等来治疗AD,取得了一定的治疗效果,但还未取得根本性突破.

·热点数据排行·

截至2015年4月14日,中国知网(CNKI)和Web of Science(WOS)的数据报告显示,以老年痴呆症(Alzheimer disease)为词条检索到的期刊文献分别为10675与8476条,本专题将相关数据按照:研究机构发文数、作者发文数、期刊发文数、被引用频次进行排行,结果如下.

研究机构发文数量排名(CNKI)

研究机构发文数量排名(WOS)

作者发文数量排名(CNKI)

作者发文数量排名(WOS)

期刊发文数量排名(CNKI)

期刊发文数量排名(WOS)

根据中国知网(CNKI)数据报告,以老年痴呆症(Alzheimer disease)为词条检索到的高被引论文排行结果如下.

国内数据库高被引论文排行

根据Web of Science统计数据,以老年痴呆症(Alzheimer disease)为词条检索到的高被引论文排行结果如下.

国外数据库高被引论文排行

·推荐综述·

阿尔茨海默病的防治策略研究进展*

倪嘉缵,陈平,刘琼,郑易之,何晓阳,宋国丽,应明,续旭

(深圳大学生命科学学院 深圳市海洋生物资源与生态环境重点实验室 深圳市微生物基因工程重点实验室,深圳 518060)

1被冷落的重要发现

1901年11月25日,一位51岁的老妇人Suguste D带着认知能力受阻的表情走进了阿罗伊斯-阿尔茨海默医生的诊室,医生详细记录了她的病史,主要表现为认知、记忆及理解能力下降,并对患者随访了4年.1906年该患者去世后,阿尔茨海默医生获得了她的脑切片,并用尼氏染色法对该样本进行了详细观察,发现有小米粒的病灶及较深染色的神经纤维,即以后被称为β-淀粉样(β-amyloid,Aβ)斑块及神经纤维缠结(neurofibrillary tangles,NFT)的两种主要病变.同年阿尔茨海默在图宾根报告了他的重要发现,遗憾的是该报告并未受到重视.1907年他发表了著名论文《大脑皮层特异性疾病研究》,然而这一超前发现几乎被忽视了近半个世纪.后来Kraepelin教授为了纪念发现者,提出将该病命名为阿尔茨海默病(Alzheimer’s disease,AD).中国在1995年审定的《神经医学名词表》中亦正式定名该病为阿尔茨海默病,通俗常称“老年痴呆”症.有人认为痴呆会对患者造成很大的心理压力,也会引起社会歧视,因此建议更名,港台地区常称“失智症”或“认知症”.本文采用其学术名称“阿尔茨海默病”.

2AD防治已成为全球关注热点

20世纪中叶以来,随老年人口的快速增加及AD发病率的增高,AD防治已成为全球关注热点.据2010年失智症报告数据显示,全球约有3560万AD患者,且以每20年增加1倍的速度增加,至2030年将达6500万人,而多发于发展中国家.目前发展中国家AD患者占全球AD患者的56%,预计2050年将增至71%.该病耗费的社会成本超过世界GDP的1%(约6040亿美元).2010年英国用于AD患者的费用约380亿美元,是用于癌症患者的2倍.

中国是世界上老年人口基数及AD患者基数最大的国家,也是老龄化速度最快的国家.据美国有关统计表明,各国65岁以上人口比例从7%上升到14%需要的时间是:法国85年,美国66年,英国45年,中国只需25年.联合国预测,2028-2038年为我国老年人口急速增加阶段,届时65岁以上人口将超过3亿,年均增1000万,而AD发病率则随年龄增大急增.

尽管AD发病率与年龄的关系因评估方法及人群数目不同而异,但总趋势是随年龄增大发病率增高.如我国对一组60岁以上人群的调查发现,60~64岁发病率为1.40%,65~69岁为1.89%,70~74岁为3.12%,75~79岁为5.95%,80~84岁为9.82%,85~89岁为16.62%,90~94岁为37.90%.

有报告预测2030年全球AD患者分布为:美洲1.48亿、欧洲1.40亿、亚洲2.75亿、非洲0.39亿,其中亚洲居首位,这缘于中国、印度等亚洲国家人口基数大,且经济迅速发展,人民生活水平和医疗条件不断改善,人口平均年龄快速提高,AD患者人数也必然迅速增加.

目前发展中国家用于AD患者的费用远小于发达国家,许多高龄的AD患者仅被视为衰老,其医疗及照顾大部份由家庭担负.我国从 1979年开始实行独生子女计划生育政策后,独生子女的父母现已步入老年,但他们却无法依靠家庭及子女的力量照顾老龄AD患者.因此社会及医疗机构必须提前做好承担照顾患AD老年群体的准备.

世界各国对AD的防治已提上日程,如美国1990年制定了“脑的10年计划”,在各州成立了AD协会,最近又出台了国家级AD研究计划(National Plan to Address Alzheimer’s Disease).我国于1998-1999年2次召开主题为“跨世纪的脑科学—老年痴呆症致病机理与防治”和“脑科学与智能开发”的香山会议,并将AD研究列入国家“863”和“973”项目.近年关于AD研究论文迅速增加,据Web of Science数据库检索,2002-2012年有关AD的文献多达166046篇,其中有关治疗的53431篇,预防的10178篇,临床的39170篇.

据陈传锋等介绍,中国有关AD的研究文献有13037篇,涉及流行病学调查的占1.68%,风险因素的占37.4%,临床表现与诊断的占9.8%,治疗与干预的占40.2%,其他方面的占10.9%.

3AD的病理特征

AD的病理特征很多,其中,Aβ在神经细胞外聚集沉淀形成老年斑(senile plaque,SP),以及tau蛋白过度磷酸化造成微管损伤和NFT是AD两个重要病理特征,其他还有沟回增宽、脑萎缩、神经元大量丢失和胶质增生、新皮质的神经元密度下降、颞叶的神经元丢失严重和炎症等.

AD患者的海马角锥体细胞与同龄相比下降近51%,突触丢失,因而严重影响神经元之间的信号传递,在大脑皮质部分出现斑块及神经元中发生颗粒空泡变性.AD患者的乙酰胆碱转移酶含量比正常人下降近80%,神经递质乙酰胆碱显著减少,金属硫蛋白失调,金属离子动态平衡紊乱等,这些诱因产生的氧化应激是神经细胞毒性和AD形成的关键.此外,AD发病因素还与某些信号传导分子,如胞内Ca2+水平升高,及蛋白激酶和磷酸酯酶平衡失控等相关.

4AD病因及分子机制

AD病因及分子机制十分复杂,至今尚不很明确,在此仅作简要评述.

AD机制与衰老过程密切相关.病因学说有十多种,如胆碱能学说、Aβ级联学说、氧化应激学说、神经细胞凋亡学说、谷氨酸能假说、免疫与炎症学说、基因遗传学说、有毒金属离子学说、钙代谢紊乱学说以及雌激素缺陷等.李文彬等提出AD发病机制ABC学说,即A为脑衰老(aging),B为Aβ(beta-amyloid),C为神经递质通道(channel).我们认为AD是一种多因素引起的病变,发病机制也必然有多种,其中Aβ级联学说、tau蛋白过度磷酸化、衰老与氧化应激、神经递质通道等学说占主要地位.

脑衰老的原因源于自由基衰老学说,正常机体中活性氧物种(reactive oxygen species,ROS)处于内稳态,如产生过量的ROS或体内ROS的清除体系减弱,使机体处于氧化应激状态,就会引发一系列后续事件.该过程对脑衰老尤为重要,因脑的耗氧量占人体总耗氧量的20%~30%,而重量仅占体重的2%~3%,脑中易氧化的不饱和脂类含量高,ROS清除能力弱,所以脑组织更易受到ROS的攻击.衰老、缺血、感染、炎症、氧化应激及基因突变等多种因素都可促使Aβ的产生和聚集,而Aβ产生后又会诱发氧化应激,促进自由基的形成,损伤神经元,导致胞内ROS升高,引起膜脂质损伤;也可作用于细胞离子通道,引起胞内Ca2+浓度升高;还可诱导神经元凋亡,激活caspase,促进Aβ前体蛋白APP裂解释放Aβ,引起线粒体损伤、线粒体DNA突变等,这些反应又会通过多种途径加强Aβ的神经毒性,引发AD神经病理改变.经以上连锁反应,AD患者脑内产生大量Aβ,并聚集沉积形成老年斑.Aβ是最早被确定形成老年斑的主因,其产生的源头为淀粉样前体蛋白APP,该蛋白经3种酶即α、β和γ分泌酶(secretase)切割后形成Aβ1-40及Aβ1-42肽段,因后者更容易形成沉淀,而对细胞有毒性.随后的研究认为:Aβ1-42聚集形成的纤维是斑块的主要成分并具有神经细胞毒性,但这种认识也受到质疑.目前比较公认的是:Aβ寡聚体是主要的致病因子.有趣的是,最近有报道证明Aβ寡聚体能在神经元之间迅速传播,也有否定Aβ是AD的主要病因的报道,认为Aβ这类蛋白是机体为保护自身而合成的,它能作为分子伴侣起消炎等作用,只有当产生错误折叠后才会形成纤维以清除错误折叠的蛋白.综上所述,有关Aβ从单体到寡聚体及形成纤维的过程,其机理及毒性尚需深入探讨.遗憾的是,以Aβ作为靶分子的新药研究几乎都以失败告终.这从另一侧面说明AD的成因不能只用单一因素加以阐明,针对单靶点开发的药物也难以对治疗AD有效.

AD患者脑内除了有Aβ聚集沉淀形成的SP外,还有在神经元内形成的NFT.NFT是AD另一个重要病理特征,其主要成分是起稳定微管作用的tau蛋白.由于蛋白激酶和磷酸酯酶的失衡而导致tau蛋白的过度磷酸化,破坏了微管的稳定性,从而使神经元微管结构被破坏.tau蛋白的磷酸化受cAMP依赖性蛋白激酶A(protein kinase A,PKA,又称激酶A)、酪蛋白激酶-1(casein kinase-1,CK-1)和糖原合成酶激酶-3(glycogen synthasekinase-3,GSK-3)等多种蛋白激酶的调控.现已发现,tau中能发生异常磷酸化的位点有21个,其中AD患者具有的异常磷酸化位点包括:Ser-198、Ser-199、Ser-202、Thr-205、Thr-231、Ser-235、Ser-262、Ser-400和Ser-404,但各磷酸化位点与其在稳定微管中的作用机制,目前尚不十分清楚.

文献论述了神经递质受体与AD的关系,如激活毒蕈碱型受体1(muscarinic receptor 1,M1受体)提高可溶性淀粉样蛋白(soluble amyloid precursorprotein,SAPP)的释放,M受体激动剂能调控GSK-3和PKC等,从而减轻tau蛋白的磷酸化程度.烟碱型受体(nicotine receptor,N受体)如烟碱乙酰胆碱受体α7亚基(α7 nAChR)上具有与Aβ直接结合的位点,Aβ作用于这些位点引起相关信号转导和产生级联反应.N受体还参与了APP的加工过程. 文献详细研究了这一系列受体与AD的关系,有助于阐明AD的病因,且能从中优选药物研制的新靶点.

5AD相关基因

因遗传因素发病的AD患者称为家族遗传性AD(familial Alzheimer’s disease,FAD),相关基因有APP、早老素(presenilin,PS,有PS1和PS2两种亚型)和载脂蛋白E(ApoE),其中APP、PS1和PS2基因常见于FAD,仅覆盖少于2%的AD患者,约71%的FAD家族具有PS1和APP基因的常染色体显性突变,这两种基因突变常见于60岁以前发病的AD患者.ApoE基因则是唯一散发性AD(sporadic Alzheimer’s disease,SAD)相关的基因.

在SAD患者中未发现APP基因突变,而在FAD患者中已发现25种APP突变,其中几种突变发生在靠近APP基因的Aβ编码区及其周围,即APP基因的第16和17外显子中,如在FAD患者的APP外显子17中,第2149碱基位点的突变可使Aβ1-40或Aβ1-42明显增加,抑制α分泌酶活性而提供有利于β和γ分泌酶的底物,导致Aβ过度产生并促进斑块形成.一项对1795名冰岛人全基因组数据筛查发现:APP基因673位的碱基由A突变为T可大大降低患AD的几率.在85岁以上人群中,没有携带这种突变基因的老人患AD的概率是携带者的7.5倍.由于该突变干扰了β分泌酶的切割能力,进而使Aβ的形成减少了40%.在AD病变过程中,PS参与了细胞内Ca2+信号通路的调控,还能通过调节γ分泌酶的活性而裂解APP,并产生具有神经毒性的Aβ,以及通过Notch和Wnt信号转导途径促进tau蛋白的异常磷酸化,从而在SP和NFT形成过程中起着重要致病作用.在FAD家系中,PS1基因的错义突变约占FAD中所有基因突变的80%,能够导致外来信号刺激下星形胶质细胞内Ca2+的存储及释放发生异常,从而促进FAD患者的神经炎性病变.但PS2基因的错义突变则比较少见,在FAD中仅发现了PS2基因的N141I和M239V两个突变位点.ApoE在脑内主要由星形胶质细胞和小胶质细胞分泌,可将胆固醇从星形细胞运输到神经元.ApoE位于19q13.32,该位点有3个等位基因(ε2、ε3和ε4).ApoEε4的基因突变体是目前已知最具危险性的晚发型AD的遗传性因素之一,40%~60%的AD患者是该基因变异型的携带者,说明ApoEε4基因与AD的发病密切相关,它可能增加了患者对AD的易感性,从而增加发生AD的危险性,降低了患者发病年龄,使发病年龄提前10~15年.然而ApoEε4基因增加AD易感性的确切机制目前还不清楚.相反ApoEε2则具有保护功能.2009年,Harold和Lambert两个课题组分别完成的两项与AD相关的全基因组关联性研究(GenomeWide Association Studies,GWAS)结果在《Nature》和《Genetics》上同时发表.Harold对1.6万名受试者(5900例AD患者,余为对照)进行了为期2年的研究,结果显示:凝集素(clusterin,CLU,又称载脂蛋白J,ApoJ)和磷脂酰肌醇结合网格蛋白装配蛋白(phosphatidylinositol bindingclathrin assembly protein,PICALM)基因与晚发型AD相关,对AD发生风险起直接作用.CLU基因并非少数人才有,只是不同人种所含CLU在具体位点的核苷酸多态性存在差异性,患AD的风险与不同位点单核苷酸多态性相关.CLU主要存在2种等位基因:C等位基因和T等位基因,白人携带C等位基因的比例高达88%.对白种人AD患者的研究发现,CLU的C等位基因携带者患晚发型AD的几率较T等位基因携带者高1.16倍,但具体作用机制尚不清楚.另有报道:CLU基因损害覆盖在大脑神经元外侧起保护作用的髓鞘质,使其功能减弱,但青少年时期并不会出现认知能力减退,因为大脑能自动修补,随着年龄增长,自动修补能力减弱,认知能力就会渐减,最终导致AD在晚年发作.该报道中的CLU基因是哪种等位基因,文章未提及.与此相反,有报道认为CLU是一种与AD相关的多功能蛋白,可作为分子伴侣与淀粉纤维结合,抑制蛋白聚集,从而保护细胞.CLU在脂质运输中的作用与ApoE类似,可与脂蛋白受体结合参与脑中Aβ裂解.此外,CLU作为补体活化反应抑制剂,可抑制炎症反应与补体活化反应下游区蛋白的聚集.但该报道未提及CLU是哪种等位基因.也有报道指出:CLU蛋白在体内的表达量决定了CLU的不同生物功能.因此,对于CLU在AD形成和发展中出现的两面性问题,应从其等位基因类型和蛋白表达量高低等因素综合分析得出结论.PICALM分布在突触结构前后,参与了网格蛋白介导的细胞内吞作用,在神经递质的传递方面发挥重要作用.约9%的AD患者存在PICALM基因突变.在患者的大脑中发现突触数量减少,生化分析显示突触密度的降低对患者认知功能的影响大于 Aβ斑块和 NFT的作用.PICALM 参与受体介导的胞吞作用(receptor-mediated endocytosis,RME),RME与含有ApoE及CLU的脂蛋白颗粒介导的脂质内摄及运输有关,是突触小泡再循环的重要部分.AD中RME异常可能导致脑内及通过血脑屏障的Aβ运输及清除减少.除CLU和PICALM之外,Harold等也提到桥连整合蛋白1(bridging integrator protein-1,BIN1)及失效蛋白1(disabled 1,DAB1)与AD密切相关,它们均能影响AD脑中NFT等主要病理特征的形成.BIN1同PICALM一样参与RME过程,通过形成管状膜结构,使微管细胞骨架与细胞膜相连.而DAB1则主要通过参与酪氨酸磷酸化及神经元中微管的功能发挥作用.Lambert等对6000例AD患者和8600多例对照进行研究,分析这些患者的基因图谱,还发现一种名为补体成分[3b/4b]受体1(complement receptor 1,CR1)的基因也与AD有关.这种蛋白是人体抗感染天然免疫系统中一个重要的组成因子,许多自身免疫性和感染性疾病与该基因的多态性有关,它与 Aβ的清除过程也有关系.CR1可能参与了AD发病过程中重要的、可由CLU抑制的补体级联反应.不过CLU突变基因和CR1突变基因对整体患病风险的提升作用却并不明显,大约只有15%,即这两个基因的作用比ApoE基因要小得多.最近的研究又发现CR1可通过与ApoEε4的相互作用加剧AD神经病理学特征的产生.研究人员指出,该次发现的3个基因广泛存在于人群中,10%的AD病例可能与CLU基因有关,9%与PICALM有关,4%与CR1有关.找到阻止这些基因发生不良变异的方法,也可能成为研究治疗药物的靶点.另一与AD密切相关的基因是分拣蛋白相关受体(sortilin-related receptor 1,SORL1),它是一种可与脂蛋白结合、调节其胞吞作用、表达于中枢及外周神经系统中的膜蛋白受体,参与APP在细胞器间的运输,并与膜内颗粒及高尔基体外侧网络的APP相互作用,使APP再分布于高尔基体,减少其Aβ形成过程.早在2007年Rogaeva等就已在SORL1基因中发现了几个与AD相关的SNP位点,虽有人对该结果表示怀疑,但在2011年发表的一项GWAS研究中,该结果得到了肯定.功能实验同样给Mayeux等人提供了证据,在SORL1蛋白表达量低的人脑内,Aβ的含量比较高.最近,由美国44所大学和研究机构共同完成的一项研究,从大量人群调查中,发现了与AD相关的4个新基因:MS4A、CD2AP、CD33和EPHA1.英国等地的学者也发表了相似的研究结果,发现ABCA7、MS4A6A/MS4A4E、EPHA1、CD33和CD2AP与AD密切相关.遗憾的是这些研究都只提示基因对疾病的易感性,并未解释其生物学机制.有趣的是,这些基因都与胆固醇代谢和炎症有关.可以设想,应激和炎症产生皮质醇和胆固醇的衍生物,引发了Aβ蛋白质的错误折叠,使细胞的质量控制机制超负荷运转血液里不溶性蛋白质不断增加.这些不溶性蛋白质聚集在一起,进而引起血液中血小板的聚集及形成缠结,阻碍了细胞周围重要物质的运输,导致细胞死亡.这说明预防炎症、增强蛋白质重新折叠、改善蛋白质的溶解性、促进血液里血小板的清除,均有利于 AD防治.还有报道认为胆固醇-25-羟化酶、低密度脂蛋白受体、巨噬细胞移动抑制因子、α2-巨球蛋白、白介素1、HLA A2和α1-抗糜蛋白酶A等基因与AD有关,但尚缺乏基因组数据分析及相关生物学实验验证.随着GWAS(genome-wide association study)的发展,人们已有可能通过大规模群体DNA样本进行全基因组高密度遗传标记分型,寻找与AD相关的遗传突变信息,发现AD易感位点.10年来开展的近20个大规模AD的GWAS研究中,成功验证了以往研究发现的发病易感基因,同时也发现了一些新的与AD发病密切相关的基因.然而,目前所采用的GWAS技术主要针对基因组内的SNP位点进行分析,该方法可确定相关位点,但不能直接确定基因本身,且在任何特定人群中,GWAS都不能方便地识别罕见的风险等位基因位点.我国也有关于SNP方面的报道,如对中国汉族107例SAD患者的Pin1基因-667和-842位点进行基因多态性分析,但在-667和-842位点SAD组与对照组基因型频率及等位基因频率差异均无统计学意义.尽管GWAS为全面系统研究复杂疾病的遗传因素提供了一种新方法,但它仍有一定的局限性,需进一步完善.另外,随着基因测序技术的飞速发展,有人提出对外显子组进行测序、寻找与AD有关的突变.我们相信随着基因组测序工作的完善,及基于序列变异-SNP单体型图谱的构建和高通量基因分析技术的迅猛发展,加之表观遗传图谱、蛋白表达谱和生理学等学科的综合推进,更精确地获得与AD相关的基因信息将成为可能.

6AD的早期诊断

6.1影像诊断技术

据美国文献统计,若能将AD发病的时间延迟5年,10年之后AD患者可减少100万,50年后可减少400万.AD的主要病理变化一般在患者有明显临床症状前10年就能在脑内被观察到,但这时患者并无任何症状,一旦出现症状后,神经细胞已严重损伤,此时进行有效治疗的可能性不大.因此目前人们更关注AD的早期预报和干预,寻找延缓由轻度认知功能损害(mild cognitive impairment,MCI)发展成早期AD的诊断方法.近年有关AD的代谢影像学、影像学、生物标志物、基因检测及其他物理探测等有许多报道.代谢影像学包括正电子发射/计算机断层扫描(positron emission tomography/computed tomography,PET/CT)及磁共振波谱分析(magnetic resonance spectroscopy,MRS).影像学有CT和磁共振成像(magnetic resonance imaging,MRI).CT对早期AD患者主要能观察皮质萎缩、脑沟增宽,但很多脑疾病及衰老均会产生类似病变.海马是AD损伤的主要部位,而CT难以准确显示海马萎缩,且对脑白质的改变亦不太敏感,所以难以作为预报早期AD的技术.MRI的图像对诊断早期AD优于CT,可清楚区分脑灰质和白质,可通过测量海马及内嗅区的结构变化诊断早期AD.以海马萎缩作为AD患者与正常老年人的区分指标,患者若无或仅有轻度T2WI脑白质高信号时,则更倾向于诊断AD.然而,MRI技术在对其图像解释及定量化方面尚存在困难,虽在评估时MRI优于CT,但对AD的早期诊断仍有一定局限性.

利用脑部的扩散张量磁共振图像(diffusion tensor magnetic resonance imaging,DT-MRI)可以反映AD 患者脑部的受损.用模式识别法将脑部DTMRI图像中多个区域内的多个参数与AD患者脑内主要损伤区域相联系,AD组与正常组比较,海马结构和胼胝体膝部的表观扩散系数较正常组高,而各向异性分数比正常对照组低.该方法尚处研究阶段,今后有望对AD的评估增加一种辅助方法.功能 MRI(fMRI)不仅能显示脑区的激活,还能直接显示激活的部位及程度,实现了功能与结构的结合.有报道MCI和AD患者在颞叶内侧激活降低.故fMRI有望成为今后AD早期诊断的工具.

质子磁共振波谱(1H-MRS)属于代谢影像学,它能无创性检测活体内神经元的特异性标志物N-乙酰-天门冬氨酸胆碱化合物(n-acetylaspartate,NAA),反映神经退行性疾病中神经元受损的指标胆碱复合物(choline,Cho),即乙酰胆碱的前体,以及反映氧化代谢水平的乳酸(Lacate,Lac).这3条谱峰已明确得到归属,并用于活体1H-MRS的解析,可用强度基本恒定的Cr峰(Creatine /posphocreatin)作为内标.上述谱峰的比值可用于评价AD的进程.然而MRS的空间分辨率低,能明确归属的代谢产物(谱峰)有限,信号易受皮下脂肪及颅骨干扰,虽已有不少AD转基因小鼠的MRS检测报道,但在临床应用上作为早期AD诊断方法尚有难度.

单光子发射计算机断层成像技术(single photonemission computed tomography,SPECT)中99mTc造影剂被注射后快速进入脑组织,99mTc与局部脑血流量的分布呈正比,在血流丰富的脑组织中发射单光子,通过局部脑血流(regional cerebral blood flow,rCBF)的测定,客观反映脑功能的改变.AD患者的双侧颞、顶叶血流灌注下降,扣带回后部rCBF降低.虽然代谢活动的降低、脑血流的改变在一定程度上反映代谢情况变化,有助于了解脑部早期病变,但由于SPECT空间分辨率较低,特异性及准确性不高,使其应用受到限制.

代谢影像学另一技术是PET/CT.以氟代脱氧葡萄糖(18F-FDG)作为造影剂,PET能反映脑组织中葡萄糖代谢水平.AD患者脑部不同区域代谢水平有显著的降低,包括颞和顶叶等,表现为双侧顶颞后区、双侧颞叶、双侧额叶和双侧扣带后回(posterior cingulate cortex,PCC)对称性葡萄糖代谢减低,双侧顶颞后区皮质局限性对称葡萄糖代谢减低明显,与顶颞叶前部可出现较明显的分界,大脑皮质放射性减低的范围随痴呆程度加重而扩大.轻度AD只有顶叶受累,中度和重度AD颞叶和额叶也受累,其中左额叶与小脑的计数比值减低程度是区别中度和重度AD的重要指标.如将顶叶、额叶、颞叶与小脑计数比值减低的范围和程度相结合,可以诊断AD,并对AD痴呆程度做出较准确的评价.11C-PIB的问世,使PET能观察到AD患者脑内的Aβ变化.乙酰六氢吡啶(MP4A)对AchE具有较高选择性,可作为PET测定活体AchE活性的理想示踪剂,用于评估脑内AchE的活性及药物乙酰胆碱酶抑制剂的疗效.1-{6-[(2-18F-氟乙基)-甲氨基-2-萘基}-亚乙基丙二氰(18 FFDDNP)是一种脂溶性小分子化合物,能快速通过血脑屏障,染色AD患者脑内的SP和NFT.研究表明,18F-FDDNP在AD患者脑内病变较为严重区域滞留的时间明显高于正常对照组,其在颞叶、顶叶、枕叶和额叶的滞留时间较脑桥高出10%~15%,滞留时间最长的区域是海马.但这些试剂均未用于临床PET检测.2012年礼来公司(Eli Lilly)宣布,放射性诊断剂Amyvid(Florbetapir F18)获得FDA批准,可用于AD等患者脑部Aβ斑块密度的PET成像,它能特异地与Aβ结合而呈现清晰的图像.遗憾的是,除AD外,许多其他神经系统疾病及老年人脑中也存在Aβ斑块,因此Amyvid也只能作为AD诊断评估的一种辅助手段.且这种试剂半衰期短、价格昂贵,虽经FDA批准,但要广泛应用尚为时过早.我们认为,随着PET/CT及MRI技术的发展,通过进一步提高这类成像检测的灵敏度及分辨率,大幅降低其检测费用,才有可能将其在临床推广,对MCI的进展作出评估.

6.2生物标记物检测

从各种体液、血液及尿液中寻找灵敏度高、能早期预报AD的生物标志物是人们长期为之奋斗的目标.早期曾以AD患者脑脊液中Aβ40、Aβ42、总tau(t-tau)、磷酸化tau(p-tau)和特异位点磷酸化tau(包括p-tau231、p-tau181)为生物标志物.AD患者脑脊液中Aβ42较正常水平下降43%,t-tau、p-tau及特异位点磷酸化tau均升高.tau蛋白的水平在症状出现前15年就开始上升,采用脑脊液中Aβ水平预测AD,其灵敏度为91%、特异性为64%.有人认为Aβ42和tau的联合分析对AD的临床诊断具有更高准确度,脑脊液中Aβ和tau的测定已被美国AD学会和NIH纳入2011年颁布的AD早期临床诊断病理指标.然而,由于采集脑脊液是一种创伤性技术,患者在没有任何AD症状时一般不会同意抽取脑脊液.相对脑脊液样本,血液样本的采集相对容易,但血浆中Aβ40和Aβ42水平仅为脑脊液中的1%左右,浓度低、检测困难、干扰因素多、特异性差,尚难用于AD早期诊断.

文献测定了正常人和AD患者血浆内的120种分泌型信号蛋白,发现其中18种蛋白的浓度在轻中度AD患者体内发生了显著变化,这对从血液中寻找灵敏的生物标志物提供了重要信息.

尿液样品很容易得到,故人们致力于研究尿中能预报 AD的生物标志物.AD7c-NTP是在神经元中表达的神经丝蛋白(Alzheimer-associated neuronalthread protein,AD7c-NTP),该蛋白在AD患者脑组织、血液及尿液中的含量均有升高趋势,其含量与痴呆的严重程度成正比,并与胰岛素信号转导有关,AD患者尿样中AD7c-NTP的含量与病程进展有关,如有报道指出AD组与正常老年组尿液中AD7c-NTP含量分别为2.50及1.21 ng/mL,用此蛋白诊断AD的敏感性为92.3%、特异性为89.4%.但遗憾的是未见该方法推广应用.能研制出从血液或尿液中分离及浓缩这些特异性蛋白的技术,找到灵敏的生物标志物仍具有诱人前景.

值得注意的是,根据视网膜的感光神经细胞与脑细胞密切相关的原理,可用眼部的感光细胞损伤程度预报早期 AD.也有报道指出,AD患者的扩瞳反应明显敏感于正常老年人的扩瞳反应,此方法可区别MCI及AD与正常老人,诊断AD的敏感性和特异性分别为66.0%和67.65%,诊断MCI的敏感性和特异性分别71.43%和67.65%.

Hanlon等提出,在耳朵上方颞骨处用647 nm的红光进行照射,使脑内引起AD病变的Aβ及NFT产生近红外区的荧光,分析这些荧光光谱可诊断AD患者.采用这种方法对22位患者测定,其中21人符合实际.以上所有物理方法预测早期AD目前尚处于试探阶段,距临床应用还有很大距离.

7AD的防治药物

AD的防治药物大致可分成下列几类:目前已进入临床的一线治疗药物、AD疫苗及单克隆抗体、处于研究阶段的药物、辅助性治疗药物、中药及保健品类(也称medical food).

7.1目前已进入临床的一线治疗药物

AD的一线治疗药物主要是改善胆碱系统功能.乙酰胆碱酯酶抑制剂(Acetycholinesterase 1,AchE1)是目前常用的药物,对早期患者有一定疗效.最早使用的药物为他克林(Tacrine),因其对肝脏损伤严重而被淘汰.目前,长效可逆非竞争性AchE抑制剂有多奈哌齐(Donepezil,商品名为安理申)、氢溴酸加兰他敏(Glantamine)、利斯的明(Rivastigmine)及石杉碱甲(Huperzine A)等.这些药物对减少早期AD患者的神经递质乙酰胆碱的分解有一定疗效,但由于中、晚期患者脑内产生的乙酰胆碱已很少,该方法对治疗AD难见疗效.

盐酸美金刚(Akatinol Memantine,商品名易倍申)是首个非AchE抑制剂类AD治疗药,它是一种非竞争性的N-甲基-D-天冬氨酸(N-methyl-D-aspartic acid receptor,NMDA)受体拮抗剂.AD病理过程中神经元丢失的一个重要原因是突触间隙存在过多谷氨酸,使NMDA受体被过度激活,离子通道长时间开放,Ca2+内流增大,引起神经元死亡.盐酸美金刚可抑制大脑中兴奋性神经递质谷氨酸盐的活性,减少细胞内Ca2+超载,增强乙酰胆碱通道,其机制是通过阻断NMDA受体,发挥治疗AD的效果.该药也可与安理申联合使用,从而增加对中晚期AD患者疗效.

7.2AD疫苗及单克隆抗体研制

AD疫苗是全球关心的热点.但无论是采用主动免疫或被动免疫,首先都要确定靶分子.由于Aβ42是组成及结构比较清楚的AD病理性多肽,故被不少新药设计选作靶分子.首个AD疫苗是由爱尔兰都柏林的Elan公司开发的AN-1792,它对小鼠有一定疗效,但在人体临床试验中出现了极其悲惨的现象:受试者由于异常免疫细胞而产生炎症反应成为脑膜炎.该项大规模的临床试验终止于2002年.之后又出现过7个治疗性抗体疫苗,也进入临床试验的不同阶段,但均未获得成功.

国外许多大公司投以巨资的单抗类新药,曾被认为是人类在短期内克服AD的最后希望,遗憾的是这些新药全部失败,如辉瑞(Pfizer)公司的新药Dimebon投入7.5亿美元却未取得效果;Elan、Pfizer 和强生(J&J)公司联合研制的Bapineuzumab已进入III期临床,也未见到疗效;Eli Lilly公司第2个治疗AD的新药Solanezumab宣告失败,而该公司2011年推出的第1个治疗AD的新药Semagacestat,非但对AD无缓解,反而使其恶化.

有人发现AD患者体内免疫球蛋白(intravenous immunoglobulin,IVlg)降低,于是从健康人外周血制备的IVlg为8名患者进行了半年的试验,其中6人的认知状况明显好转.然而IVlg来源困难、价格昂贵,其疗效与病情的严重程度有关,并需长期使用,因而难以推广.产品Gammagard由美国Baxter International有限公司研制,但遗憾的是,2013年3月该公司宣布:在III期临床试验中,该药对AD患者的治疗未获得预期疗效,因而停止研究.至此国外治疗AD的药物几乎全部失败.有人预言,上述试验的失败可能会使制药公司在没有新思路出现之前放弃这一领域新药的研发.

7.3处于研究阶段的药物

Aβ42聚集形成的寡聚体及纤维可直接造成细胞氧化损伤、线粒体功能障碍,因此早期受到人们广泛关注,将抑制Aβ聚集、促进Aβ解聚作为“靶标”来寻求治疗AD的药物.为筛选抑制Aβ聚集的活性物质,人们建立了多种模型和方法.体外模型如用荧光染料硫代黄素T(ThT)检测Aβ不同的聚集状态(单体/寡聚体/纤维).建立高通量筛选Aβ聚集抑制物的细胞模型已成为近年研究的热点.早期人们试图合成能阻止形成折叠,且疏水性又类似于Aβ的小肽,例如分别由11个和5个氨基酸组成的抗β折叠的小肽iAβ11及iAβ5,体外实验证明它们具有一定效果.最近从天然产物中寻找抗Aβ聚集的活性物质亦多有报道,如灵芝、人参、银杏、牛膝、葛根姜黄素、迷迭香酸、去甲二氢愈创木酸、白黎芦醇及其苷化合物等,均能有效抑制Aβ42寡聚体的形成.多项研究表明,儿茶素类化合物能够有效抑制淀粉样原纤维的形成,其中的没食子儿茶素没食子酸酯(epigallocatechin gallate,EGCG)已被多次报道可高效抑制各种形式淀粉样原纤维的形成.最近又有研究发现了一类新型有机分子—咔唑菁类分子,它本身能产生强的荧光,并可与Aβ结合,抑制Aβ的聚集及纤维化.

本课题组近年利用Aβ42-EGFP融合基因转化哺乳动物细胞,在其中表达了Aβ42-EGFP融合蛋白.首次证明了来自线虫的抗脱水保护性蛋白(AavLEA1)可直接阻止 Aβ42-EGFP融合蛋白的聚集.黄芪多糖(astragalus polysaccharides,PS5)和灵芝酸(Ganoderma acid,GDA)也可阻止Aβ42-EGFP融合蛋白的聚集,但它们可能是通过蛋白酶体(proteasome)间接地发挥作用.尽管如此,抗Aβ聚集剂要用于临床,尚需克服许多困难,因为以Aβ作为药物筛选靶分子的思路受到质疑,Kurnellas等认为Aβ除与AD有关外,它本身在细胞中还具有一定生物功能.这类药物最终能否通过血脑屏障,其生物利用度和确切疗效等目前尚缺乏足够的数据.

正在开展的其他类型新药研究还有很多,如抑制β和γ分泌酶活性的药物;用金属螯合剂如铁调素(hepcidin)等去除脑内有害金属离子和过量Fe3+、Ca2+和Zn2+的金属螯合剂.2006年我国学者提出β2-肾上腺素受体被激活后会增强γ分泌酶的活性,进而增加Aβ蛋白的产生,因而β2-肾上腺素受体有可能作为AD治疗药物的靶点.然而,所有这些研究均未见体内试验的报道,若要将其应用于临床治疗,尚有较大距离.

7.4辅助性治疗药物

辅助性药物主要是针对AD产生的病因使用一些常规药物,但并不作为AD治疗的推荐用药,如抗氧化剂、维生素E、褪黑素(melatonin)、增加脑血流量的银杏制剂、减少Ca2+内流的钙通道阻滞剂(如尼莫地平)、降低血脂的他汀类药物及增加脑代谢活性的药物(如多种麦角碱类).这些单一药物并非用于AD防治,医生根据患者所处AD发病阶段某些功能的损伤严重程度进行用药.已发现这类药往往会对AD症状有改善效果.

7.5天然产物是开发AD防治新药的宝库

7.5.1从植物中开发防治

AD的新药从植物中开发治疗或延阻AD病理进程的药物是全球关注热点,在此介绍部分中药单方的研究.中药有效成分单体提取物抗AD作用的研究,如中国学者从千层塔中开发出选择性AchE抑制剂石杉碱甲(hurperzin,Hup A).Ratia M等证实,石杉碱可以选择和可逆抑制中枢神经系统AChE活性,激活蛋白激酶C/丝裂原活化蛋白激酶(mitogen-activated protein kinase,MAPK)信号通路,激活α分泌酶以及增加GSK-3β磷酸化等,通过上述机制修复三转基因AD模型小鼠认知障碍.Yang等报道Hup A可以改善APP/PS1转基因小鼠大脑皮层Aβ寡聚体引起的线粒体ATP产生下降、线粒体肿大和氧化呼吸链活性抑制,从而拓展了HupA干预AD的作用靶标.而由Hup A衍生物研发出的效果更强的抗AD新药NT-1,其I和II期临床实验正在进行.

姜黄素是姜黄根茎的提取物,也是食用咖喱的主要成分,具有抗炎、抗氧化和抗蛋白质聚集等活性.近年姜黄素被用于 AD干预.流行病学调查指出食用咖喱的印度人群其AD发病率低于美国人30%~40%.印度一项研究调查了1010例60~90岁人群食用咖喱与认知水平之间的关系,发现经常食用咖喱(>1次/月)的人,认知功能好于那些从不食用咖喱或很少使用咖喱者.该研究指出,姜黄素的强抗氧化作用能保护神经细胞、减少β分泌酶过度表达、阻断tau蛋白过度磷酸化以及与金属离子结合等,从而阻延AD.姜黄素可通过血脑屏障进入大脑组织,与Aβ沉淀形成SP特异性结合,连续给予7 d后可见SP减少.但也有报道每天口服2 g或4 g姜黄素24周的患者,按AD评估量表的评分未见提升,用药者血液中姜黄素浓度的测定数据表明:姜黄素的生物利用度偏低.若能把姜黄素制备成纳米材料、脂质体剂型或进行糖基化修饰,增加其水溶性或生物利用度,则姜黄素将是有前景的AD治疗药物.

淫羊藿的有效成分为淫羊藿甙.文献指出,给AD转基因小鼠喂饲淫羊藿甙后,其记忆能力有显著改善.淫羊藿甙可有效修复Aβ1-42所致原代培养大鼠皮层神经元树突和轴突的损伤,其机制为激活P13K/Akt通路,抑制GSK-3β活性,从而阻断tau蛋白过度磷酸化.李林等对淫羊藿黄酮/淫羊藿甙干预AD的药理学机制和临床研究进行了综述,指出淫羊藿活性成分对多种AD模型小鼠学习认知能力有修复作用,可减低海马和大脑皮层Aβ含量及SP数量,抑制APP、β分泌酶和突触核蛋白表达,增加泛素-蛋白酶体系统的Parkin和UCH-L1表达,增加突触素(SYP)和PSD-95表达,保护线粒体呼吸链,提高抗氧化作用和抑制炎症,改善海马和皮层突触超微结构的损伤.

本课题组采用三转基因AD模型小鼠,长期喂以含淫羊藿甙的饲料,2月龄AD模型小鼠经过20周用药后,水迷宫实验证明其认知能力有显著改善.将小鼠进行活体MRI及MRS检测,发现长期给予淫羊藿甙可有效逆转AD病理特征,小鼠海马神经细胞的 NAA水平下降,并减轻氧化应激所致的乳酸堆积.免疫组化检测结果发现,用药组小鼠大脑学习及短期记忆相关的前脑皮层、海马CA1、CA3和齿状回区域,胞内及胞间Aβ沉积明显减轻;同时AD小鼠大脑皮层线粒体丙酮酸脱氢酶(human pyruvate dehydrogenase-E1,PDHE1α)表达水平也明显降低.上述结果提示,淫羊藿甙可能成为有效干预AD病理进程和修复学习记忆障碍的药物,但仍需对其分子调节机制及信号通路进行深入研究.

研究证明,银杏(Ginkgo biloba)叶提取物具有多靶点效用,可以改善脑循环、调整神经细胞代谢、影响毒蕈碱样胆碱能系统,能抗Aβ沉淀引起的脑组织ROS增加和氧化损伤,被认为对预防AD有疗效.2006年在人体中进行的160 mg银杏提取物与5 mg量多奈哌齐剂量组双盲随机对照实验结果显示:银杏叶提取物EGb761与多奈哌齐均在Kurz症状检查(SKT)和临床总体印象量表(clinicalglobal impression,CGI)测评中具有改善AD认知障碍作用,但简易精神状态检查(MMSE)无差异.随后报道的多项RCT结果,对银杏提取物干预AD疗效存有争议,如法国学者在《柳叶刀》上报道的一项大型多中心双盲RCT结果,否定了EGb761有干预AD疗效.这些研究报道促使我们思考:建立反映中药多靶点、多作用途径的临床疗效评价体系的必要性和迫切性.对上述持否定结论的研究报道进行分析,不难发现其选择的实验样本基本都是75岁以上老龄人群,年龄偏大.我们认为银杏叶提取物这类药物主要是起延缓AD进程的作用,实验时应选择年龄不太高的MCI患者才能说明药物的预防作用.

人参皂苷是一种多靶点抗衰老的传统中药,对AD的作用已有大量报道,如Rg1和Rg2能降低GSK-3/PP2A活性,降低tau蛋白的过度磷酸化;而Rg2对AD模型大鼠海马神经元的结构和突触素SYN的表达均有一定保护作用.我国许多抗AD的中成药都含有人参中的皂苷类,如中成药“金思维”就是含有人参茎叶皂苷 17.9%及淫羊霍黄酮苷 33.3%的复方.韩国学者制备的含人参为主药的12味药材验方jianghonghwan水煎剂,是以人参皂甙Rg3含量来控制药品质量,对不同月龄APP/PS1转基因AD模型小鼠给药后,观察到皮层与海马Aβ聚集和SP减少及可溶性与不溶性Aβ1-40和Aβ1-42水平显著下降.其他植物药中单一组分对AD的防治也多有报道,如首乌、钩藤和知母等.

中医理论认为AD治疗方略一般是补肾填髓、活血化瘀、祛痰醒窍.国内不少复方中成药用于AD治疗,如由何首乌、淫羊藿、人参、石菖蒲、葛根和川芎6味中药制成的“参乌胶囊”,目前已经完成治疗轻中度AD III期临床试验,其药理学研究采用不同AD动物模型,全面验证了其在Aβ生成和聚集、降低tau磷酸化和NFT、抑制小胶质细胞和星形胶质细胞活化、降低炎性反应、改善线粒体能量代谢障碍、提高大脑皮层和海马ChAT/AChE比值等方面的作用.特别应指出的是该复方中几个主要标志成分能针对AD发病机制不同靶点发挥作用,从而延阻认知功能下降.

7.5.2从海洋动植物中开发防治AD新药

已有相关从海洋藻类及海洋动物的活性物质中寻找防治AD药物的报道,如从海洋藻类中获得的多糖及寡糖有可能作为预防AD药物.文献指出,从褐藻胶中获得的低分子海洋硫酸寡糖类药物HSH-971,能明显改善痴呆大鼠的学习记忆功能,提升大脑皮层及海马内超氧化物歧化酶、谷胱甘肽过氧化物酶和ATPase等酶的活性,降低丙二醛(malondialdehyde,MDA)含量,对AD具有明显防治效果.其他多糖如鼠尾藻多糖等也具有较好的抗氧化活性.

褐藻硫酸多糖具有抗脑缺血、营养神经细胞的作用,其抗氧化保护神经细胞的最小活性片段为四糖,说明糖链长度对其抗氧化损伤作用具有明显影响.动物实验表明,对痴呆型大鼠喂饲褐藻胶寡糖3 d后,该寡糖对Aβ导致的神经损伤有保护作用.AD患者脑内存在着局部炎症反应,抗炎疗法可能是延缓AD的手段之一.已证明四糖结构的寡糖有显著抗炎活性,褐藻胶的寡糖能明显抑制二甲苯致小鼠耳肿胀炎症反应,对鸡蛋清致大鼠足爪肿胀有抑制作用.AD患者脑部常出现NO大幅减少的情况,这可能对记忆的贮存造成障碍并减少脑部血液流量,使Aβ增加.因此调控脑内NO含量对改善AD症状具有一定作用.但它有双重功能,在病理情况下,大量表达的NO可导致神经损伤及炎症等病理状态,因此,选择性抑制iNOS对NO过量产生导致的疾病具有潜在治疗价值.我们的研究指出,在巨噬细胞NO的产生和LPS导致NO过高产生的炎症细胞模型中,不同结构的褐藻胶寡糖有不同的作用.在AD预防时,可以选择能够产生NO的寡糖作为保健品;当发病后,可选择抗炎活性比较强的成分.因而这些多糖及寡糖也是用于AD防治的潜在药物.

近年,我国学者对中药单体和单方标准化提取物的研究已深入到分子机制和相关信号通路领域,但规范化、大样本、毒理学及确切疗效指标等研究深度尚不够.动物实验中给药时间一般较短,临床研究中随机、客观和可重复性等不尽规范,因而研究成果不容易被认可.我们认为AD病因机制和病理进程复杂漫长,而早期阶段的线粒体生物转运失衡和突触可塑性降低先于大量Aβ沉淀和NFT发生,因此,可将线粒体生物转运失衡和突触可塑性降低作为中药神经保护和神经营养、再生作用基础研究的重点,利用原代神经细胞的快速筛选平台及转基因动物模型,在探索主要作用机制基础上,将有效成分单体复方配伍,有利于结合中医药“君臣佐使”和“固本治标”的理念,一方面发挥中药辨证施治的原理,另一方面应用现代药理学方法,完全有可能从中药宝库中发掘防治AD的新药.

7.6延缓AD发展的保健药物

由于治疗AD的新药研制长期没有进展,且AD患者一般在症状出现前10多年脑内已开始病变,故寻找毒性低,能长期服用,可作为早期干预及延缓AD多种病因的保健药就成为焦点.

7.6.1辅酶Q-10有望成为延缓AD发展的药物

辅酶Q-10(coenzyme Q-10)的主要生理功能是在线粒体內膜协助电子传递,从而生成能量物质ATP供应各系统,且稳定细胞膜结构.它具有清除过量ROS、延缓衰老与脑病变等作用.由于线粒体损伤、ATP产量降低及过量ROS产生等问题均能通过补充辅酶Q-10解决,辅酶Q-10与AD的关系已引起广泛关注,如辅酶Q-10可抑制晚期转基因AD小鼠的Aβ水平及氧化应激.对转APP突变基因小鼠PTg19959喂饲辅酶Q-10 6个月后,发现氧化应激、海马区Aβ沉积斑块大小及数量、水迷宫测定的认知能力等均有明显改善.辅酶Q-10对防止tau蛋白过度磷酸化的作用也有报道,以转tau突变基因P301S小鼠为模型,经6个月喂饲辅酶Q-10后,皮层区的tau过度磷酸化降低,线粒体中与电子传递有关的关键酶均得到上调,转基因小鼠的营养状态及存活率均有提高.

本课题组采用双向荧光差异凝胶电泳(2DDIGE)及串联基质辅助激光解析电离飞行时间质谱技术,研究辅酶Q-10对三转基因小鼠的血清蛋白质组学的影响,结果显示:AD小鼠与野生对照小鼠相比,在辅酶Q-10处理与未处理AD小鼠中,共鉴定出23个差异蛋白点,其中辅酶Q-10“修饰”蛋白点8个,包括CLU、alpha-2-macrophageprecursor等与AD密切相关蛋白.AD小鼠海马和皮层Western blot结果显示,辅酶Q-10可降低tau蛋白在Ser396、Ser262 和Thr231位点的磷酸化,对突触标记物synaptophysin及突触后致密物质(PSD-95)的丢失有保护作用.

以上结果表明,辅酶Q-10对早期AD的干预均具有正面结果,如可增加线粒体中产生ATP的主要酶系、降低氧化应激、減少Aβ的沉积及减轻tau蛋白的过度磷酸化等,这些作用均有利于延缓AD的发展.目前存在的问题是:缺乏一定规模人群的试验数据,每人每日应服用辅酶Q-10的剂量尚缺乏统一认可的数据.文献曾提到对治疗神经退行性疾病如AD和PD等需使用大剂量辅酶Q-10,约900~1200 mg/d.转基因小鼠实验所使用的剂量一般在200 mg/kg左右,如折算为成人用量,每人每日使用剂量也相当大.然而能否允许使用大剂量辅酶Q-10作为AD和PD患者的早期干预药物,各国尚无政策规定.因此,若能启动一项用大剂量辅酶Q-10对早期AD患者进行长期干预的人群实验,将为早期干预药物用于临床治疗提供科学依据.

7.6.2补充叶酸、VB6及VB12可降低血液中同型半胱氨酸,减少AD风险

体内同型半胱氨酸Hcy源自蛋氨酸,其形成途径为:①Hcy与丝氨酸缩合为胱硫醚,称为转硫化途径;②蛋氨酸在S-腺苷蛋氨酸合成酶催化下与ATP作用生成S-腺苷蛋氨酸,作为甲基供体,同时形成S-腺苷同型半胱氨酸(S-adenosyl homocysteine,SAH),水解后形成腺苷及Hcy.而生成的Hcy由蛋氨酸合成酶催化,以VB6和VB12作为辅酶再转化为蛋氨酸.目前已公认Hcy是心血管病的重要危险因子,其与AD的关系也有不少报道.当血浆Hcy水平超过14 μmol/L时,发生AD的危险性增加2倍.血浆Hcy高于5 μmol/L,发生AD的风险会增加40%.此外,研究还发现,高Hcy的AD患者比低Hcy者在3年内神经细胞萎缩的速度明显加快.Hcy会促进tau蛋白的磷酸化.tau蛋白的磷酸化是磷酸化与去磷酸化的平衡过程.蛋白磷酸酶2A(PP2A)起去磷酸化作用.在蛋氨酸循环中形成的SAH是甲基转移酶的竞争性抑制剂.Hcy浓度升高可致SAH增多,从而使细胞内甲基化作用降低,使PP2A减少,引起tau蛋白的过度磷酸化.Hcy还会引起Aβ增多、DNA损伤、氧化应激加剧、大脑叶颞中央回萎缩等.对AD病人血浆中Hcy浓度的测定表明,AD组与对照相比有明显差别,AD患者为25.70 μmol/L,轻度AD为21.98 μmol/L,中度AD为25.52 μmol/L,重度AD为31.47 μmol/L,对照组仅14.55 μmol/L.对168名已出现轻度认知功能障碍的老人进行为期两年的临床对比实验,每日服用大剂量VB6、VB12和叶酸,2年后服药老人大脑萎缩程度减缓30%.体外实验证明Hcy对大脑神经元具有直接杀伤作用.本课题组测定了不同年龄段(1、2、4、8和12月龄)AD三转基因小鼠血浆中Hcy水平的变化.结果表明:早在2月龄时,AD小鼠血浆Hcy的水平就显著高于对照组.随年龄增长,Hcy水平逐步升高,到4月龄后达到稳定.而对照组中2月龄的野生型小鼠血浆中Hcy水平很低.同时还发现AD小鼠血浆Hcy的升高早于细胞内Aβ的聚集及空间记忆的损伤.因此认为,降低体内Hcy可作为预防AD的措施之一.同时,Hcy也有可能作为预报早期AD的标志物.故服用一定剂量的VB6、VB12及叶酸有助于降低患AD的风险.

7.6.3硒化合物作为早期AD干预药物的前景

硒对维持中枢神经系统的生物功能具有重要作用.硒缺乏与AD具有很大相关性,AD组体内硒的水平与对照组相比明显偏低,血清、红细胞和指甲中硒浓度也明显降低.ApoE4等位基因携带者指甲的含硒量比非携带者显著降低.补充含硒化合物可以改善认知功能.然而也有不同结果的报道:如AD患者与健康对照者的脑脊液和血清硒水平没有明显差异,AD病人海马区或脑杏仁核区硒水平显著升高等.上述结果的不一致性,可能与受试者基因型、饮食习惯、生活方式及所摄取硒的形态、检测部位等的不同有关.

AD患者脑细胞具有高氧化应激水平.硒蛋白及硒酶在脑中具有还原活性,其抗氧化功能可通过多种途径实现,如硒蛋白 R是一种亚砜还原酶,而AD患者脑内Aβ中35位的蛋氨酸被氧化成亚砜后易形成沉淀,硒蛋白R可将被氧化成亚砜的残基还原为蛋氨酸,从而起到调节氧化还原平衡的作用.

硒化合物也直接与产生的Aβ斑块有关.亚硒酸钠通过降低BACE1表达而限制Aβ的产生,通过保护神经细胞免受脂质氧化和Aβ毒性,改善对神经细胞的损伤.喂食有机硒Sel-Plex的APP/PS1小鼠,其Aβ斑块沉淀、DNA和RNA氧化水平均显著降低,GPx活性显著增高.AD中硒蛋白的表达与Aβ形成及脂质过氧化密切相关.我们课题组发现,不同形式的SelM对ROS产生和Aβ聚集的作用各不相同.全长SelM能减少ROS的产生、降低Aβ的聚集,而截短体SelM则与全长SelM具有相反的作用和效果,即在缺硒状态不利于ROS的去除. 说明不同形式SelM对AD的作用与氧化应激和Aβ产生、聚集密切相关.此外,我们还发现了人脑中与SelR相互作用的蛋白为CLU,两个蛋白通过相互作用,在促表达、抗氧化、增强蛋氨酸亚砜还原酶活性方面发挥协同作用.近年有报道称神经细胞毒性主要由Aβ寡聚体所致,成熟的Aβ纤维毒性较小.伴侣分子可通过加速多肽在水溶液中的聚集,来减少Aβ的神经毒性,而CLU就是一种伴侣分子.因此,研究SelR与CLU的相互作用及对Aβ聚集的影响、进而研究硒与AD的关系,对揭示硒预防AD机理具有重要意义.

过量金属离子,如Cu+、Fe2+和Zn2+等对神经细胞具有一定的毒副作用,其动态平衡失调会引起氧化应激和产生ROS.内源性金属离子如Fe2+或Cu+与过氧化氢作用产生高活性的羟自由基,使神经细胞受损.氧化应激产物HNE抑制Zn2+的输出,造成锌动态平衡紊乱,引起AD中tau蛋白的过度磷酸化和Aβ寡聚体的生成.硒化合物可以通过清除ROS、产生GPx活性和与金属离子配位结合的方式发挥抗氧化、维持金属内稳态的功能,防止神经退行性病变.我们实验室研究了硒蛋白与金属离子的结合性质及其对Aβ聚集的作用,发现SelP和SelM具有结合过渡金属离子的性质,并能抑制Zn2+介导的Aβ非纤维化聚集、ROS产生和对神经纤维细胞的毒性.

我们还以三转基因AD小鼠作为动物模型,给不同月龄的小鼠喂饲硒代蛋氨酸,3个月后发现给药组的小鼠行为学有显著的改善,硒代蛋氨酸对突触前后蛋白的下降有修复作用,能显著降低tau蛋白的表达及tau蛋白磷酸化水平.

以tau为靶分子的AD防治药物的相关研究目前不多.文献对8种不同硒化合物的研究表明:硒酸钠能特异地促进PP2A活性,减轻AD小鼠模型中的tau蛋白病理特征,有望发展成以tau为靶点治疗AD的药物.然而硒蛋白防治AD的作用机理尚不够深入,且缺乏一定规模的临床试验.鉴于上述原因,目前既要加强对AD防治作用机理及临床的研究,同时还需对非高硒地区的老年人群补硒,如对早期AD患者补充能使血液中GPx及SelP接近饱和的小剂量硒(据报道,体重58 kg的成人,满足SelP合成所需硒用量约为49 μg/d).我们认为,通过补充适量硒,能在一定程度上延缓AD病程,故含硒化合物有望成为预防早期AD的化学干预制剂.

7.6.4胰岛素及椰子油能减轻中度AD症状

有人将AD称为III型糖尿病,兼有I型及II型糖尿病特征,即胰岛素缺乏及胰岛素受体受损(不敏感).胰岛素能通过血脑屏障,而某些神经元也能产生胰岛素及胰岛素信号转导蛋白.胰岛素和胰岛素样生长因子(IGFs)除了影响神经元的生存,还影响能量代谢和神经递质的释放,启动与记忆有关的信号转导.关于胰岛素及其受体与AD的关系,文献指出:在糖尿病胰岛素抵抗时,由于胰岛素降解酶的底物是胰岛素和Aβ,胰岛素作为Aβ的竞争性结合底物,可抑制Aβ降解,加重中枢神经细胞Aβ的沉积,促进AD的发生.具有胰岛素抵抗的慢性高胰岛素血症患者,及空腹或餐后血胰岛素水平增高的正常人,其认知功能减退甚至痴呆发生的危险性显著升高.而在胰岛素缺乏的链脲佐菌素(streptozotocin,STZ)糖尿病模型鼠海马神经元中,因其胰岛素降解酶表达减少,同样可使Aβ沉积.中枢神经系统中几乎所有细胞都能合成APP,胰岛素能促进α分泌酶的活性,使APP产生可溶性Aβ前体蛋白sAPPα.当胰岛素缺乏或功能异常,可使具有神经营养的sAPPα减少,Aβ增加,促进SP形成和神经元的退行性病变.胰岛素能促进Aβ从神经元胞内释放到胞外,并结合到胰岛素样生长因子I(IGF-I)诱导的载体蛋白上.

tau蛋白是神经细胞主要的微管相关蛋白.tau蛋白的异常磷酸化破坏了与微管的结合,而tau蛋白磷酸化的平衡是由磷酸激酶及磷酸酯酶所调控,其中GSK-3β,Akt/PKB和PP2A是关键,它们受胰岛素信号网络所调控,胰岛素和IGF1通过激活PI3K/PKB通路下调GSK-3活性,从而保持tau蛋白的正常磷酸化及与微管的结合功能.

体外细胞实验指出,外周胰岛素水平下降可抑制磷脂酰肌醇-3激酶( phosphatidylinositol 3 kinase,PI-3K)的活性,而PI-3K自身活性下降可导致下游的GSK-3β由非活化型转变为活化型,从而使tau蛋白在Thr181、Ser199、Ser202、Thr212、Thr217和Ser396等位点发生磷酸化.

有报道称,用胰岛素滴鼻和使用胰岛素增敏剂如罗格列酮,通过提高胰岛素敏感性,对早期AD有一定疗效.

国外一本有趣的书提出,AD患者脑内葡萄糖吸收受阻,可使用酮类化合物(ketones)保持脑能量供应.该书作者的丈夫患中期 AD,经服用椰子油后认知水平显著提高,这可能是由于椰子油中含有大量饱和脂肪酸转化为酮类化合物.但这些治疗方法尚缺乏严格的科学数据及广泛的人群试验,只能作为个案参考.

迄今为止,糖尿病与AD间的关系仍很不清楚.糖尿病是AD的危险因子,或AD是糖尿病的危险因子尚存争议,有待进一步开展研究.在2012年AD协会国际会议上,荷兰科学家Philip Scheltens报告,用保健品治疗轻度AD患者,经24周人群试验,认知能力有明显改善.他们提出的配方为:二十碳五烯酸(EPA)、二十二碳六烯酸(DHA)、磷酯、胆碱、尿苷单磷酸(UMP)、VE、硒、VB6、VB12和叶酸.该组成中前两种DHA及EFA是鱼油中的主要成分,可防止脑血管的堵塞及供给脑内必要的养分. 卵磷酯及胆碱是神经递质乙酰胆碱及细胞膜的原料.UMP进入脑内能促进神经细胞轴突生长,增加神经递质的释放,上调神经丝蛋白-70及M蛋白.而硒与叶酸的作用机制前面已提及.非常有趣的是,Philip Scheltens 的尝试与我们的研究思路不谋而合,我们认为在上述配方中需再增加大剂量辅酶Q-10,其防治AD的疗效将会更加显著.遗憾地是这种疗法因无法招募志愿者进行大样本人群试验,尚难以推广.

展望

有人指出,AD将是下个世纪危害人类健康的第一杀手.虽然长期以来癌症占据首位,但目前不管是癌症早期诊断的方法,还是靶向药物均有长足进展,癌症患者的生存时间已有大幅提高.但对AD既缺乏早期预报的方法,又没有能治愈的药物.随着老龄化社会的快速到来,AD患者的迅速增加,不仅为患者家庭带来巨大的痛苦,还将影响社会、经济的可持续发展.AD病因复杂,从基因突变到表观遗传学,特别是与人体衰老过程紧密相关,所以无论从病因还是从防治策略均应摒弃单一因素的思路,从多因素及内在相互联系的系统生物学观点进行研究.影响AD的基因不断被发现,有些是先天遗传造成SAD,有些是在胎儿早期因某些DNA的不同甲基化所致,而大量是在人体不断衰老过程中导致的DNA损伤及突变.随着高通量DNA测序技术的发展,采用GWAS等方法,除了发现新的基因及SNP,研究这些基因间的关系及表达产物的作用外,还应采用网络及子网络方法研究各种蛋白、因子和酶的相互作用.对引起AD的病因,除了己有的十多种学说外,要进一步将衰老学与AD病因学相联系,因衰老过程是在漫长的时间域中,各种生理过程受内外环境的影响逐渐发生变化.AD是神经退行性疾病的一种,许多引起衰老的因素,均与AD起因相关.AD病因的复杂性及神经细胞的不可再生性,决定了若选择单一分子作靶标进行新药及疫苗的研发将会困难重重.西方多数药厂已丧失信心,想退出具有诱人前景的AD治疗药物研究领域.但山穷水尽疑无路,柳暗花明又一村,若将治疗重点前移,着重放在AD发生早期,综合用药以减缓AD病程,从中药的整体理论、辩证理论及双向调节理论出发,发掘符合重心前移的药物.另外,许多所谓medical food的保健药,无论在转基因小鼠还是在小规模的人群试验中均出现过显著疗效.若将治疗重心前移,还需解决对AD的预报方法,PET/CT、fMRI虽目前尚未被普遍采用,但仍是一种能实现对AD早期预报的有应用前景的方法.随着高灵敏度、高分辨率的质谱技术及代谢组学、蛋白质组学的发展,从血液及尿液中寻找能进行早期预报的生物标志物,是从事AD研究的科技人员的重任.相信通过国内外科学家的共同努力,在不远的将来征服AD必然会有所突破.

·经典文献推荐·

基于Web of Science检索结果,利用Histcite软件选取LCS(Local Citation Score,本地引用次数)TOP 30文献作为节点进行分析,得到本领域推荐的经典文献如下.

来源出版物:British Medical Journal,1978,2(6150): 1457-1459

Clinical-diagnosis of Alzheimers-disease - report of the nincds-adrda work group under the auspices of department-of-health-and-human-services task-force on Alzheimers-disease

McKhann G; Drachman D; Folstein M; et al.

Abstract: Clinical criteria for the diagnosis of Alzheimer's disease include insidious onset and progressive impairment of memory and other cognitive functions. There are no motor,sensory,or coordination deficits early in the disease. The diagnosis cannot be determined by laboratory tests. These tests are important primarily in identifying other possible causes of dementia that must be excluded before the diagnosis of Alzheimer's disease may be made with confidence. Neuropsychological tests provide confirmatory evidence of the diagnosis of dementia and help to assess the course and response to therapy. The criteria proposed are intended to serve as a guide for the diagnosis of probable,possible,and definite Alzheimer's disease; these criteria will be revised as more definitive information become available.

来源出版物:Neurology,1984,34(7): 939-944

Alzheimers-disease - initial report of the purification and characterization of a novel cerebrovascular amyloid protein

Glenner GG; Wong CW

Abstract: A purified protein derived from the twisted beta-pleated sheet fibrils in cerebrovascular amyloidosis associated with Alzheimer's disease has been isolated by Sephadex G-100 column chromatography with 5 M guanidine-HC1 in 1 N acetic acid and by high performance liquid chromatography. Amino acid sequence analysis and a computer search reveals this protein to have no homology withany protein sequenced thus far. This protein may be derived from a unique serum precursor which may provide a diagnostic test for Alzheimer's disease and a means to understand its pathogenesis.

来源出版物:Biochemical and Biophysical Research Communications,1984,120(3): 885-890

Amyloid plaque core protein in Alzheimer-disease and down syndrome

Masters CL; Simms G; Weinman NA; et al.

Abstract: We have purified and characterized the cerebral amyloid protein that forms the plaque core in Alzheimer disease and in aged individuals with Down syndrome. The protein consists of multimeric aggregates of a polypeptide of about 40 residues(4 kDa). The amino acid composition,molecular mass,and NH2-terminal sequence of this amyloid protein are almost identical to those described for the amyloid deposited in the congophilic angiopathy of Alzheimer disease and Down syndrome,but the plaque core proteins have ragged NH2termini. The shared 4-kDa subunit indicates a common origin for the amyloids of the plaque core and of the congophilic angiopathy. There are superficial resemblances between the solubility characteristics of the plaque core and some of the properties of scrapie infectivity,but there are no similarities in amino acid sequences between the plaque core and scrapie polypeptides.

来源出版物:Proceedings of the National Academy of Sciences of the United States of America,1985,82(12): 4245-4249

The precursor of Alzheimers-disease amyloid-a4 protein resembles a cell-surface receptor

Kang J; Lemaire HG; Unterbeck A; et al.

Abstract: Alzheimer's disease is characterized by a widespread functional disturbance of the human brain. Fibrillar amyloid proteins are deposited inside neurons as neurofibrillary tangles and extracellularly as amyloid plaque cores and in blood vessels. The major protein subunit(A4)of the amyloid fibril of tangles,plaques and blood vessel deposits is an insoluble,highly aggregating small polypeptide of relative molecular mass 4500. The same polypeptide is also deposited in the brains of aged individuals with trisomy 21(Down's syndrome). We have argued previously that the A4 protein is of neuronal origin and is the cleavage product of a larger precursor protein. To identify this precursor,we have now isolated and sequenced an apparently full-length complementary DNA clone coding for the A4 polypeptide. The predicted precursor consists of 695 residues and contains features characteristic of glycosylated cell-surface receptors. This sequence,together with the localization of its gene on chromosome 21,suggests that the cerebral amyloid deposited in Alzheimer's disease and aged Down's syndrome is caused by aberrant catabolism of a cell-surface receptor.

来源出版物:Nature,1987,325(6106): 733-736

·高被引论文摘要·

被引频次:142

糖尿病脑病与老年性痴呆

盛树力

(篇首)糖尿病(DM)脑病的概念形成于60年代,以后在临床和实验性糖尿病鼠都有研究,病人主要表现轻、中度认知功能障碍.由于这些表现并不十分严重或缺乏对这方面的了解而常被忽视.我国心理学界的研究表明,注射胰岛素和口服降糖药的病人存在认知功能障碍,而饮食控制组的病人认知功能在正常范围,提示病人认知功能障碍与病情严重程度有关.1型糖尿病人认知功能损害主要在联想记忆和学习技能注意力方面,2型糖尿病人认知功能损害主要在学习和记忆方面,可能存在记忆提取过程的缺陷.

糖尿病脑病;老年性痴呆;认知功能损害;淀粉样;胰岛素受体底物;蛋白磷酸化;神经元纤维缠结;神经营养作用;过度磷酸化;α分泌酶

来源出版物:中华内分泌代谢杂志,2001,17(1): 58-59

被引频次:136

老年性痴呆辨治

王永炎

摘要:痴呆又称呆病,是以呆傻愚笨为主要临床表现的一种神志疾病.老年性痴呆系发生于老年期或老年前期的一种慢性进行性精神衰退性疾病,病理改变以大脑的萎缩和变性为主.是老年医学领域的一个重要课题,对探讨中医对老年性痴呆病因病机的认识,加强防治措施,是很有意义的.

关键词:老年性痴呆;老年前期;衰退性;脑髓空虚;脑髓消;髓海不足;狂证;齿枯发焦;智能障碍;脑为元神之府

来源出版物:中国医药学报,1991,9(2): 49-51

被引频次:127

老年痴呆的发病机理及治疗策略

张均田

摘要:(篇首)老年痴呆可分为阿尔茨海默病(Alzheimer’s disease,AD)、血管性痴呆和二者并存的混合型痴呆.流行病学的调查显示,目前世界上老年痴呆的发病率每年男性为30.5/1000,妇女为48.2/1000(Bachman 1992).老年痴呆是一种综合病,以高级认知功能障碍为特征,以老年斑、神经纤维缠结和神经元丢失为主要的病理改变,下面分别叙述老年痴呆的发病机理和治疗策略.

关键词:老年痴呆;阿尔茨海默病;细胞凋亡;发病机理;治疗策略

来源出版物:药学学报,2000,35(8): 635-640

被引频次:116

老年性痴呆与淤血的关系

颜德馨,吕立言

摘要:老年性痴呆和老年前期精神病是一组慢性进行性精神衰退性疾病,临床表现以痴呆症状最为突出,病理改变以大脑的萎缩和变性为主,起病于中年或老年前期者称为老年前期精神病,起病于老年期者称为老年性痴呆.我们在长期的临床实践中认识到与本病与瘀血密切相关,并用活血化瘀的方法治疗本病,取得了较好的疗效,现浅述如下.

关键词:老年前期;老年性痴呆;痴呆症状;通窍活血汤;哭笑无常;衰退性;呆病;言语含糊;肝气郁;通天草

来源出版物:辽宁中医杂志,1991,(8): 37-38

被引频次:98

老年痴呆简易测试方法研究——MMSE 在城市老年居民中的测试

李格,沈漁邨,陈昌惠,等

摘要:本研究将简易精神状态检查法(MMSE)作为痴呆的筛选工具用于北京市西城区1090名60岁及以上老年人群进行测试,结果表明,该量表除少数项目需根据我国文化背景作某些修改外,仍具有简单,易行,易接受的特点,老年人文化程度、躯体活动状况、年龄和性别对MMSE得分有影响,其中以文化程度影响最大,这将给筛选结果带来偏性,尤其是在文盲率较高的人群可能更为突出.本文作者根据我国老年人群文化程度低的特点,提出了对不同文化程度者采用不同的筛选阳性界线值的具体方法,使MMS-E更适用于我国社会文化背景.我们认为在缺乏我国自己的痴呆筛选工具时,使用MMSE作为痴呆的人群筛选工具具有一定实际意义.

关键词:筛选工具;老年居民;MMSE;躯体活动;文化程度;测试方法研究;文盲率;定向力;筛选结果;假阳性

来源出版物:中国心理卫生杂志,1988,2(1): 12-18

被引频次:94

痴呆和阿尔茨海默病的发病率

张明园,陈佩俊,何燕玲,等

摘要:目的:调查痴呆和阿尔茨海默病(AD)的发病率及其与性别、年龄、教育程度的关系.方法:采用二阶段法,在1987年调查的基础上,于1992年对上海市静安区的居民进行调查.按美国精神障碍诊断和统计手册第3版修订本、美国神经病和言语障碍和中风研究所/阿尔茨海默病和相关疾病协会的标准诊断痴呆和AD.结果:1992年在实访的3024人中,痴呆和AD的年发病率:55岁以上为0.71%和0.42%,60岁以上为0.91%和0.56%,65岁以上为1.31%和0.89%.经单因素、双因素和logistic回归分析示,发病率与性别无关,与年龄及教育程度密切相关.结论:痴呆和AD的发病率与世界各国报道相似.教育对痴呆的发生具保护作用,文盲为危险因素.

关键词:发病率;痴呆;阿尔茨海默病;流行病学

来源出版物:中华精神科杂志,1998,(4):195-198

被引频次:83

一种新的老年痴呆动物模型

罗焕敏,陈子晟

摘要:目的:建立一种新的老年痴呆(AD)小鼠模型,用于AD及其治疗药物的研究.方法:选用NIH小鼠,腹腔注射D-半乳糖120 mg/ kg和亚硝酸钠90 mg/ kg,每天1次,连续60 d,制备老年痴呆动物模型.通过水迷宫试验,脑组织匀浆蛋白质含量、乙酰胆碱酯酶(Ach E)和超氧化物歧化酶(SOD)活性的测定,脑组织病理切片HE染色和刚果红染色,比较老年痴呆模型小鼠和正常小鼠的差异.结果:与对照组比,模型组小鼠的逃避潜伏期明显增加(P<0.01),脑内蛋白质含量没有明显差异,脑内Ach E活性增加(P<0.01),SOD活性下降(P<0.01);模型组小鼠出现触须脱落,大脑皮层出现类老年斑病理改变,海马和大脑皮层神经元变性坏死.结论:D-半乳糖和亚硝酸钠合并制备的老年痴呆模型在一定程度上模拟了AD的发病特点,可作为AD及其治疗药物研究的一种新模型.

关键词:阿尔茨海默病;学习记忆;超氧化物歧化酶;老年斑

来源出版物:中国老年学杂志,2003,(3): 179-181

被引频次:81

老年性痴呆病人家居安全的护理干预

徐永能,卢少萍,符霞,等

摘要:目的:降低老年性痴呆病人家居安全问题的发生率.方法:通过调查78例老年性痴呆病人家居安全问题的发生情况,针对最为常见的家居安全问题,如误吸、误服、跌倒、走失、热伤、自伤或伤人等给予为期1年的护理干预,并将干预前后家居安全问题的发生率进行u检验.结果:干预后误吸、误服、跌倒、走失、热伤的发生率显著低于干预前(P<0.01),而干预前后自伤或伤人的发生率无显著变化(P>0.05).结论:针对性地进行家居安全方面的护理干预,能有效降低痴呆病人家居安全问题的发生率,改善病人的生活质量,减轻家庭和社会的负担.

关键词:老年痴呆病人;家居安全;护理干预

来源出版物:中华护理杂志,2004,39(3):185-187

被引频次:78

老年痴呆中医病因病机理论的认识与思考

魏翠柏,田金洲,贾建平

摘要:(篇首)老年痴呆是老年人脑功能失调的一种表现,是以智力衰退和行为、人格变化为特征的一种病症,包括阿尔茨海默氏病(Alzheimer’s disease,AD)、血管性痴呆(vascular dementia,VaD)、混合型痴呆和其它(外伤、帕金森)痴呆.其中阿尔茨海默氏病和血管性痴呆是老年痴呆中最主要的两大类型,患病率占所有痴呆90%以上.随着人口的老龄化,发达国家老年痴呆已上升为常见死亡原因的第4位.

关键词:老年痴呆;病因病机;阿尔茨海默氏病;血管性痴呆

来源出版物:中华中医药杂志,2005,20(8): 496-498

被引频次:78

老年痴呆症病人家属健康教育需求的研究

张月华,卢少萍,符霞,等

摘要:目的:了解老年痴呆症病人家属健康教育需求.方法:采用自行设计的调查表,对65例老年痴呆症病人家属的健康知识和健康教育需求进行评定.结果:92.3%的病人家属知道疾病的诊断,但缺乏护理知识与技能;93.8%希望与医护人员面对面直接交谈健康教育知识;出院后86.2%选择护士家访.结论:医护人员应重视老年痴呆症病人家属的健康教育需求,有针对性地进行宣教.

关键词:老年痴呆症;病人家属;健康教育

来源出版物:护理学杂志,2003,18(7):542-543

被引频次:17677

Clinical-diagnosis of Alzheimers-disease - report of the nincds-adrda work group under the auspices of department-of-health-and-human-services task-force on Alzheimers-disease

Mckhann G; Drachman D; Folstein M; et al.

Abstract: Clinical criteria for the diagnosis of Alzheimer’s disease include insidious onset and progressive impairment of memory and other cognitive functions. There are no motor,sensory,or coordination deficits early in the disease. The diagnosis cannot be determined by laboratory tests. These tests are important primarily in identifying other possible causes of dementia that must be excluded before the diagnosis of Alzheimer’s disease may be made with confidence. Neuropsychological tests provide confirmatory evidence of the diagnosis of dementia and help to assess the course and response to therapy. The criteria proposed are intended to serve as a guide for the diagnosis of probable,possible,and definite Alzheimer’s disease; these criteria will be revised as more definitive information become available.

来源出版物:Neurology,1984,34(7): 939-944

被引频次:4611

Gene dose of apolipoprotein-e type-4 allele and the risk of Alzheimers-disease in late-onset families

Corder EH; Saunders AM; Strittmatter WJ; et al.

Abstract: The apolipopotein E type 4 allele(APOE-epsilon4)is genetically associated with the common late onset familial and sporadic forms of Alzheimer’s disease(AD). Risk for AD increased from 20% to 90% and mean age at onset decreased from 84 to 68 years with increasing number of APOE-epsilon4 alleles in 42 families with late onset AD. Thus APOE-epsilon4 gene dose is a major risk factor for late onset AD and,in these families,homozygosity for APOE-epsilon4 was virtually sufficient to cause AD by age 80.

来源出版物:Science,1993,261(5123): 921-923

被引频次:3544

The precursor of Alzheimers-disease amyloid-a4 protein resembles a cell-surface receptor

Kang J; Lemaire HG; Unterbeck A; et al.

Abstract: Alzheimer’s disease is characterized by a widespread functional disturbance of the human brain. Fibrillar amyloid proteins are deposited inside neurons as neurofibrillary tangles and extracellularly as amyloid plaque cores and in blood vessels. The major protein subunit(A4)of the amyloid fibril of tangles,plaques and blood vessel deposits is an insoluble,highly aggregating small polypeptide of relative molecular mass 4500. The same polypeptide is also deposited in the brains of aged individuals with trisomy 21(Down’s syndrome). We have argued previously that the A4 protein is of neuronal origin and is the cleavage product of a larger precursor protein. To identify this precursor,we have now isolated and sequenced an apparently full-length complementary DNA clone coding for the A4 polypeptide.The predicted precursor consists of 695 residues and contains features characteristic of glycosylated cell-surface receptors. This sequence,together with the localization of its gene on chromosome 21,suggests that the cerebral amyloid deposited in Alzheimer’s disease and aged Down’s syndrome is caused by aberrant catabolism of a cell-surface receptor.

来源出版物:Nature,1987,325(6106): 733-736

被引频次:3227

Alzheimers-disease-initial report of the purification and characterization of a novel cerebrovascular amyloid protein

Glenner GG; Wong CW

Abstract: A purified protein derived from the twisted beta-pleated sheet fibrils in cerebrovascular amyloidosis associated with Alzheimer’s disease has been isolated by Sephadex G-100 column chromatography with 5 M guanidine-HC1 in 1 N acetic acid and by high performance liquid chromatography. Amino acid sequence analysis and a computer search reveals this protein to have no homology with any protein sequenced thus far. This protein may be derived from a unique serum precursor which may provide a diagnostic test for Alzheimer’s disease and a means to understand its pathogenesis.

来源出版物:Biochemical and Biophysical Research Communications,1984,120(3): 885-890

被引频次:2993

The consortium to establish a registry for Alzheimers-disease(cerad). Part II. standardization of the neuropathologic assessment of Alzheimers-disease

Mirra SS; Heyman A; Mckeel D; et al.

Abstract: The Neuropathology Task Force of the Consortium to Establish a Registry for Alzheimer’s Disease(CERAD)has developed a practical and standardized neuropathology protocol for the postmortem assessment of dementia and control subjects. The protocol provides neuropathologic definitions of such terms as “definite Alzheimer’s disease”(AD),“probable AD”,“possible AD”,and “normal brain” to indicate levels of diagnostic certainty,reduce subjective interpretation,and assure common language. To pretest the protocol,neuropathologists from 15 participating centers entered information on autopsy brains from 142 demented patients clinically diagnosed as probable AD and on eight nondemented patients. Eighty-four percent of the dementia cases fulfilled CERAD neuropathologic criteria for definite AD. As increasingly large numbers of prospectively studied dementia and control subjects are autopsied,the CERAD neuropathology protocol will help to refine diagnostic criteria,assess overlapping pathology,and lead to a better understanding of early subclinical changes of AD and normal aging.

Keywords: adrda work group; clinical-diagnosis; senile plaques; vascular dementia; parkinsons-disease; amyloid deposits; morphology;criteria

来源出版物:Neurology,1991,41(4): 479-486

被引频次:2946

Segregation of a missense mutation in the amyloid precursor protein gene with familial Alzheimers-disease

Goate A; Chartierharlin MC; Mullan M; et al.

Abstract: A LOCUS segregating with familial Alzheimer’s disease(AD)has been mapped to chromosome 21(ref. 1),close to the amyloid precursor protein(APP)gene 2-5. Recombinants between the APP gene and the AD locus have been reported 6-8 which seemed to exclude it as the site of the mutation causing familial AD. But recent genetic analysis of a large number of AD families has demonstrated that the disease is heterogeneous 9. Families with late-onset AD do not show linkage to chromosome 21 markers 9,10. Some families with early-onset AD show linkage to chromosome 21 markers,but some do not 8,9,11. This has led to the suggestion that there is non-allelic genetic heterogeneity even within early onset familial AD 8,9. To avoid problems that heterogeneity poses for genetic analysis,we have examined the cosegregation of AD and markers along the long arm of chromosome 21 in a single family with AD confirmed by autopsy. Here we demonstrate that in this kindred,which shows linkage to chromosome 21 markers,there is a point mutation in the APP gene. This mutation causes an amino-acid substitution(Val --> Ile)close to the carboxy terminus of the beta-amyloid peptide. Screening other cases of familial AD revealed a second unrelated family in which this variant occurs. This suggests that some cases of AD could be caused by mutations in the APP gene.

Keywords: secondary structure; linkage; chromosome-21; CDNA; prediction; markers; defect; locus; DNA

来源出版物:Nature,1991,349(6311): 704-706

被引频次:2815

Apolipoprotein-e - high-avidity binding to beta-amyloid and increased frequency of type-4 allele in late-onset familial Alzheimer-disease

Strittmatter WJ; Saunders AM; Schmechel D; et al.

Abstract: Apolipoprotein E is immunochemically localized to the senile plaques,vascular amyloid,and neurofibrillary tangles ofAlzheimer disease. In vitro,apolipoprotein E in cerebrospinal fluid binds to synthetic betaA4 peptide(the primary constituent of the senile plaque)with high avidity. Amino acids 12-28 of the betaA4 peptide are required. The gene for apolipoprotein E is located on chromosome 19q13.2,within the region previously associated with linkage of late-onset familial Alzheimer disease. Analysis of apolipoprotein E alleles in Alzheimer disease and controls demonstrated that there was a highly significant association of apolipoprotein E type 4 allele(APOE-epsilon4)and late-onset familial Alzheimer disease. The allele frequency of the APOE-epsilon4 in 30 random affected patients,each from a different Alzheimer disease family,was 0.50 +/- 0.06; the allele frequency of APOE-epsilon4 in 91 age-matched unrelated controls was 0.16 +/- 0.03(Z=2.44,P=0.014). A functional role of the apolipoprotein E-E4 isoform in the pathogenesis of late-onset familial Alzheimer disease is suggested.

Keywords: central nervous-system; cholesterol transport; regeneration; lipoproteins; expression; astrocytes; receptors; brain

来源出版物:Proceedings of the National Academy of Sciences of the United States of America,1993,90(5): 1977-1981

被引频次:2812

Amyloid plaque core protein in Alzheimer-disease and down syndrome

Masters CL; Simms G; Weinman NA; et al.

Abstract: We have purified and characterized the cerebral amyloid protein that forms the plaque core in Alzheimer disease and in aged individuals with Down syndrome. The protein consists of multimeric aggregates of a polypeptide of about 40 residues(4 kDa). The amino acid composition,molecular mass,and NH2-terminal sequence of this amyloid protein are almost identical to those described for the amyloid deposited in the congophilic angiopathy of Alzheimer disease and Down syndrome,but the plaque core proteins have ragged NH2termini. The shared 4-kDa subunit indicates a common origin for the amyloids of the plaque core and of the congophilic angiopathy. There are superficial resemblances between the solubility characteristics of the plaque core and some of the properties of scrapie infectivity,but there are no similarities in amino acid sequences between the plaque core and scrapie polypeptides.

来源出版物:Proceedings of the National Academy of Sciences of the United States of America,1985,82(12): 4245-4249

被引频次:2638

Cloning of a gene bearing missense mutations in early-onset familial Alzheimers-disease

Sherrington R; Rogaev EI; Liang Y; et al.

Abstract: Some cases of Alzheimer’s disease are inherited as an autosomal dominant trait. Genetic linkage studies have mapped a locus(AD3)associated with susceptibility to a very aggressive form of Alzheimer’s disease to chromosome 14q24.3. We have defined a minimal cosegregating region containing the AD3 gene,and isolated at least 19 different transcripts encoded within this region. One of these transcripts(S182)corresponds to a novel gene whose product is predicted to contain multiple transmembrane domains and resembles an integral membrane protein. Five different missense mutations have been found that cosegregate with early-onset familial Alzheimer's disease. Because these changes occurred In conserved domains of this gene,and are not present in normal controls,they are likely to be causative of AD3.

Keywords: precursor protein GENE; caenorhabditis-elegans; human genome; apolipoprotein-e; chromosome-14; identification; linkage;library; allele; clones

来源出版物:Nature,1995,375(6534): 754-760

被引频次:2571

Association of apolipoprotein-e allele epsilon-4 with late-onset familial and sporadic Alzheimers-disease

Saunders AM; Strittmatter WJ; Schmechel D; et al.

Abstract: Apolipoprotein E,type epsilon4 allele(APOE epsilon4),is associated with late-onset familial Alzheimer’s disease(AD). There is high avidity and specific binding of amyloid beta-peptide with the protein ApoE. To test the hypothesis that late-onset familial AD may represent the clustering of sporadic AD in families large enough to be studied,we extended the analyses of APOE alleles to several series of sporadic AD patients. APOE epsilon4 is significantly associated with a series of probable sporadic AD patients(0.36 +/- 0.042,AD,versus 0.16 +/- 0.027,controls [allele frequency estimate +/-standard error],p=0.00031). Spouse controls did not differ from CEPH grandparent controls from the Centre d'Etude du Polymorphisme Humain(CEPH)or from literature controls. A large combined series of autopsy-documented sporadic AD patients also demonstrated highly significant association with the APOE epsilon4 allele(0.40 +/- 0.026,p less-than-or-equal-to 0.00001). These data support the involvement of ApoE epsilon4 in the pathogenesis of late-onset familial and sporadic AD. ApoE isoforms may play an important role in the metabolism of beta-peptide,and APOE epsilon4 may operate as a susceptibility gene(risk factor)for the clinical expression of AD.

Keywords: amyloid precursor protein; genetic-linkage; missense mutation; e polymorphism; beta-peptide; chromosome-19; pedigree;dementia; locus

来源出版物:Neurology,1993,43(8): 1467-1472

·推荐论文摘要·

阿尔茨海默病诊断标准的演变

王晓妮,唐毅,韩璎

摘要:阿尔茨海默病(Alzheimer’s disease,AD)是老年痴呆最常见的病因,随着人口老龄化程度加剧,A患病率也逐年增加,给社会和个人带来极大负担,早期诊断AD已成为当今研究的热点.文中将从最早期的AD痴呆诊断标准解析,逐渐过度到目前最新的AD临床前期主观认知下降的研究框架,试图为早期诊断AD提供新思路.

关键词:阿尔茨海默病;主观认知下降;早期诊断;诊断标准;生物标记物

来源出版物:医学研究生学报,2015,28(2): 195-198联系邮箱:韩璎,13621011941@163.com

660例老年性痴呆患者中医证候学研究

张玉莲,张连城,李强,等

摘要:目的:探究老年性痴呆的中医证候学特征.方法:利用多中心横断面流行病学调查方法收集660例老年性痴呆患者.建立老年性痴呆中医证候信息采集表,对患者的一般资料、病因病机、脉症资料、证型等进行信息收集.对四诊信息出现的所有症状、舌象、脉象、证型进行频数统计,对老年性痴呆出现的主要症状进行因子分析,总结分析老年性痴呆的主要症状及证候分布特点.结果:老年性痴呆痴呆最常见的10个症状是善忘、失算、齿脱、发白、腰膝酸软、反应迟钝、步履迟缓、乏力、转盼遗忘、神情呆滞.老年性痴呆的主要证候要素为精亏、阳虚、阴虚,次要证候要素为瘀、痰,病位主要在肾,亦与心、肝、脾相关.证型以肾虚为主(占86.36%),其次为气滞血瘀证(5.15%)、痰浊阻窍证(3.94%).结论:老年痴呆发病与肾关系密切,肾虚为老年性痴呆发病的基础,瘀、痰为其发展和加重的关键因素.

关键词:老年性痴呆;流行病学调查;证候要素;肾虚

来源出版物:中医杂志,2015,56(3): 235-239联系邮箱:张玉莲,zhyl220@126.com

葛根素对阿尔茨海默病细胞模型Aβ蛋白的抑制作用

梅峥嵘,谭湘萍,黄汉辉,等

摘要:目的:在过表达β淀粉样前体蛋白的SH-SY5Y细胞上(SH-SY5Y/APP695)观察葛根素对β淀粉样蛋白(β-amyloid protein,Aβ)生成的作用,探讨其防治阿尔茨海默病的机制.方法:葛根素2.5,5和10 μmol·L-1处理SH-SY5Y/APP细胞24 h,MTT法检测细胞活力,ELISA试剂盒测定细胞外Aβ1-40和Aβ1-42水平;Western blot蛋白质印迹法检测APP及β-分泌酶的蛋白表达变化;荧光法测β-分泌酶的活性;RT-PCR法检测β-分泌酶转录的变化.结果:葛根素可剂量依赖性的减少SH-SY5Y/APP695细胞外Aβ1-40、Aβ1-42的水平;酶活性分析显示2.5,5和10 μmol·L-1的葛根素分别抑制了15%,30%和40%β-分泌酶的活性.Western blot印迹结果显示,葛根素能剂量依赖性抑制β-分泌酶蛋白表达,2.5,5和10 μmol·L-1的葛根素使β-分泌酶的蛋白表达分别减少至82%,71%和45%,与空白对照组比较差异均具有统计学意义(P<0.05).结论:葛根素通过下调β-分泌酶蛋白的表达、抑制β-分泌酶的活性减少Aβ的形成,这可能是葛根素防治阿尔茨海默病作用的重要机制之一.

关键词:阿尔茨海默病;葛根素;β淀粉样蛋白

来源出版物:中国现代应用药学,2015,32(1):5-9联系邮箱:谭湘萍,ping_txp@126.com

认知障碍初步评价表在中重度阿尔茨海默病中的初步应用

梅刚,陆蓉,徐俊,等

摘要:目的:探讨认知障碍初步评价表(cognitive-12,COG-12)区分中、重度度阿尔茨海默病(Alzheime’s disease,AD)的能力.方法:61例中度和55例重度阿尔茨海默病患者为研究对象,对所有对象进行COG-12、AD8、MMSE及CDR测试.结果:重度AD患者COG-12、AD8、MMSE总分明显高于中度AD.多元回归分析提示COG-12评分不受被试者年龄及受教育年限的影响.COG-12能有效区分中、重度AD,敏感度为90.9%,特异度为70.5%.结论:COG-12对中、重度AD具有较好的区分能力.

关键词:阿尔茨海默病;认知障碍初步评价表;量表

来源出版物:南京医科大学学报(自然科学版),2014,34(5): 637-640联系邮箱:徐俊,neurojun@126.com

电针对Aβ25-35致阿尔茨海默病模型大鼠cAMP/PKA/CREB信号转导通路的影响

易显富,彭力,张泽月,等

摘要:目的:探讨电针对Aβ25-35导致的阿尔茨海默病模型大鼠应用电针刺激后cAMP/PKA/CREB信号转导通路的变化.方法:48只健康雌性SD大鼠随机分为AD模型组、电针组、假手术组和正常对照组各12只.模型组与电针组采用Aβ25-35建立AD模型后电针组给予电针刺激,模型组未给予电针刺激;假手术组双侧海马注射等量生理盐水;正常对照组不做任何处理.4组均采用Morri水迷宫实验检测大鼠记忆与空间探索能力,采用分光光度计法检测脑组织超氧化物歧化酶与丙二醛水平,采用放射免疫法检测海马cAMP水平,采用免疫组织化学法检测海马5-羟色胺1A受体、蛋白激酶A与p-CREB蛋白表达水平,采用Western blot检测海马总Tau蛋白表达水平及Tau蛋白Ser396位点磷酸化情况.结果:与模型组比较,电针组、假手术组与对照组逃避潜伏期缩短、跨越平台次数增多、目标象限停留时间延长(P<0.05),脑组织中超氧化物歧化酶、5-羟色胺1A受体、蛋白激酶A及p-CREB水平增高(P<0.05),丙二醛、总Tau蛋白、pTau-Ser396、c-fos蛋白水平降低(P<0.05);电针组总Tau蛋白、c-fos及PKA水平高于假手术组(P<0.05),与对照组比较差异无统计学意义(P>0.05).结论:电针可明显提高阿尔茨海默病大鼠学习记忆功能和空间探索能力,可能是通过拮抗cAMP/PKA/CREB信号转导通路相关蛋白的异常改变起作用.

关键词:阿尔茨海默病;电针;Aβ25-35;cAMP/PKA/CREB;信号通路

来源出版物:中华实用诊断与治疗杂志,2014,28(2): 128-130联系邮箱:彭力,meliangpengfei@163.com

丹参酮ⅡA对阿尔茨海默病模型大鼠脑组织caspase-3、Akt与NF-κB表达的影响

温蒲圆,罗浩,周丽,等

摘要:目的:观察丹参酮ⅡA(TanⅡA)对β淀粉样蛋白(Aβ)诱导的大鼠脑组织Akt、NF-κB、caspase-3表达水平的影响.方法:30只雄性SD大鼠随机分为假手术组、AD模型组和TanAⅡ治疗组.在大鼠脑海马内注射Aβ方法建立AD动物模型.免疫荧光法检测Aβ1-16标记部位和表达水平,免疫组化法检测caspase-3的表达水平,免疫组化染色和Western blot法检测Akt、NF-κB的表达水平.结果:Aβ1-16在假手术组中无表达,而在AD模型组和TanAⅡ治疗组二者间Aβ1-16表达水平无明显差异(P>0.05).Akt的表达在模型组低于假手术组和TanAⅡ治疗组,差异有统计学意义(P<0.05),而模型组NF-κB与caspase-3的表达水平明显高于假手术组和TanAⅡ组,差异显著(P<0.05).结论:TanAⅡ可降低模型鼠NF-κB与caspase-3的表达水平,且上调Akt的表达.

关键词:β淀粉样蛋白;阿尔茨海默病;凋亡;丹参酮AⅡ

来源出版物:细胞与分子免疫学杂志,2014,30(2): 155-159联系邮箱:周军,junz@xy3yy.com

盐酸多奈哌齐治疗老年痴呆的疗效研究

杨红,朱德生

摘要:目的:探讨盐酸多奈哌齐治疗老年痴呆患者的临床疗效.方法:选择2009年1月—2010年9月106例本院就诊的老年痴呆患者,随机分为治疗组53例及对照组53例,两组均给予基础治疗,治疗组在此基础上给予盐酸多奈哌齐治疗.选择治疗前、随访3个月时及2年时患者的临床症状、体征及简易精神状况检查表(MMSE)评分、日常生活能力量表(ADL)评分进行分析比较.结果:106例老年痴呆患者中男44例(41.5%),女62例(58.5%);年龄60~90岁,60~75岁82例(77.3%),76~90岁24例(22.7%);大学学历以下73例(68.87%);大学及大学以上学历33例(31.13%);阿尔茨海默病(AD)72例(67.9%);血管性痴呆(VaD)23例(21.7%),其他类型痴呆11例(10.4%).随访2年期间失访14例,实访92例.治疗前及随访3个月时两组MMSE评分及ADL评分等级比较,差异均无统计学意义(P>0.05)而随访2年时两组MMSE评分及ADL评分等级比较,差异均有统计学意义(P<0.05).两组均有不良反应发生,给予对症处理后好转,且两组不良反应发生率比较,差异无统计学意义(χ2=1.38,P>0.05).结论:盐酸多奈哌齐治疗老年痴呆安全有效,不良反应较少,值得临床推广应用.

关键词:痴呆;阿尔茨海默病;痴呆,血管性;随访研究

来源出版物:中国全科医学,2013,16(10): 853-856

维生素B1缺乏与老年性痴呆

李文霞,柯尊记

摘要:阿尔茨海默病(Alzheimer’s disease,AD)主要表现为认知能力下降,进行性记忆丧失,性格改变,语言功能障碍,最终发展为痴呆.AD的主要神经病理学表现为:沉积在细胞外的淀粉样蛋白斑;细胞内的神经纤维缠结;基底前脑胆碱能神经元死亡.氧化应激、线粒体损伤和代谢能力降低是AD的重要病理生理学机制.实验性维生素B1缺乏(thiamine deficiency,TD)是研究脑代谢降低引起神经元死亡的经典动物模型.TD降低脑内维生素B1依赖性代谢酶活性,导致氧化代谢异常、丘脑核团神经元特异性死亡、胶质细胞激活、炎症反应等神经退行性疾病类似的病理改变.以TD为模型的研究显示,代谢紊乱、氧化应激、内质网应激、蛋白质折叠异常和炎症反应是神经元死亡和β淀粉样蛋白聚集的重要机制.增加体内可利用的维生素B1可改善老年性痴呆模型动物的认知水平,减轻脑病理改变.这些结果提示,补充维生素B1可能是延缓老年性痴呆发展的一种有效方法.

关键词:阿尔茨海默病;β-淀粉样蛋白聚集;神经元死亡;代谢紊乱;维生素B1缺乏

来源出版物:生命科学,2013,(2):184-190联系邮箱:柯尊记,zjke@sibs.ac.cn

类叶升麻苷对冈田酸诱导的阿尔茨海默病细胞模型的保护作用研究

白鹏,彭晓明,高莉,等

摘要:目的:研究类叶升麻苷(acteoside)对冈田酸(OA)诱导的SK-N-SH神经细胞损伤的影响.方法:以20 nmol·L-1的冈田酸处理SK-N-SH神经细胞,建立AD样细胞模型,并以5,10,20 mg·L-1的类叶升麻苷拮抗其作用.通过倒置显微镜观察细胞形态,采用MTT比色法检测细胞存活率,酶标法试剂盒测定LDH渗漏率,应用Western blot技术检测神经细胞磷酸化tau蛋白的表达情况.结果:类叶升麻苷可明显改善SK-N-SH的细胞形态,提高细胞的存活率,降低细胞LDH的漏出率,下调磷酸化tau蛋白在p-Ser 199/202,p-Ser 404位点的表达,上调非磷酸化tau蛋白在Ser 202,Ser 404位点的表达.结论:类叶升麻苷对冈田酸诱导的SK-N-SH神经细胞损伤具有明显保护作用.

关键词:类叶升麻苷;冈田酸;阿尔茨海默病;保护

来源出版物:中国中药杂志,2013,38(9): 1323-1326联系邮箱:闫明,yanming21cn@sohu.com

Coding Mutations in SORL1 and Alzheimer Disease

Vardarajan BN; Zhang YL; Lee JH; et al.

Abstract: Objective: Common single nucleotide polymorphisms in the SORL1 gene have been associated with late onset Alzheimer disease(LOAD),but causal variants have not been fully characterized nor has the mechanism been established. The study was undertaken to identify functional SORL1 mutations in patients with LOAD. Methods: This was a family-and cohort-based genetic association study. Caribbean Hispanics with familial and sporadic LOAD and similarly aged controls were recruited from the United States and the Dominican Republic,and patients with sporadic disease of Northern European origin were recruited from Canada. Prioritized coding variants in SORL1 were detected by targeted resequencing and validated by genotyping in additional family members and unrelated healthy controls. Variants transfected into human embryonic kidney 293 cell lines were tested for A40 and A42 secretion,and the amount of the amyloid precursor protein(APP)secreted at the cell surface was determined. Results: Seventeen coding exonic variants were significantly associated with disease. Two rare variants(rs117260922-E270K and rs143571823-T947M)with minor allele frequency(MAF)<1% and 1 common variant(rs2298813-A528T)with MAF=14.9% segregated within families and were deemed deleterious to the coding protein. Transfected cell lines showed increased A40 and A42 secretion for the rare variants(E270K and T947M)and increased A42 secretion for the common variant(A528T). All mutants increased the amount of APP at the cell surface,although in slightly different ways,thereby failing to direct full-length APP into the retromer-recycling endosome pathway. InterpretationCommon and rare variants in SORL1 elevate the risk of LOAD by directly affecting APP processing,which in turn can result in increased A40 and A42 secretion.

Keywords: genetic-variants; sequencing data; high-frequency; association; metaanalysis; individuals

来源出版物:Annals of Neurology,2015,77(2): 215-227

DNA polymerase beta deficiency leads to neurodegeneration and exacerbates Alzheimer disease phenotypes

Sykora P; Misiak M; Wang Y; et al.

Abstract: We explore the role of DNA damage processing in the progression of cognitive decline by creating a new mouse model. The new model is a cross of a common Alzheimer’s disease(AD)mouse(3xTgAD),with a mouse that is heterozygous for the critical DNA base excision repair enzyme,DNA polymerase beta. A reduction of this enzyme causes neurodegeneration and aggravates the AD features of the 3xTgAD mouse,inducing neuronal dysfunction,cell death and impairing memory and synaptic plasticity. Transcriptional profiling revealed remarkable similarities in gene expression alterations in brain tissue of human AD patients and 3xTg/Pol beta(+/-)mice including abnormalities suggestive of impaired cellular bioenergetics. Our findings demonstrate that a modest decrement in base excision repair capacity can render the brain more vulnerable to AD-related molecular and cellular alterations.

Keywords: base excision-repair; mild cognitive impairment; increased oxidative damage; downs-syndrome patients; transgenic mouse model; double-strand breaks; amyloid-beta; a-beta; mitochondrial-DNA; synaptic dysfunction

来源出版物:Nucleic Acids Research,2015,43(2): 943-959联系邮箱:Bohr; VA vbohr@nih.gov

“Noncognitive” symptoms of early Alzheimer disease A longitudinal analysis

Masters MC; Morris JC; Roe CM

Abstract: Objectives: To observe the natural time course of noncognitive symptoms before the onset of symptomatic Alzheimer disease dementia. Methods: Using the National Alzheimer’s Coordinating Center Uniform Data Set from September 2005 to March 2013,data from cognitively normal individuals who were aged 50 years or older at first visit and had subsequent follow-up were analyzed. Survival analyses were used to examine the development of particular symptoms relative to each other on the Neuropsychiatric Inventory Questionnaire(NPI-Q),Functional Activities Questionnaire,and Geriatric Depression Scale,and to compare the development of individual symptoms for persons who did and did not receive a Clinical Dementia Rating(CDR)>0(indicating abnormal cognition)during the follow-up period. Results: The order of symptom occurrence on the NPI-Q was similar for participants who remained at CDR 0 and for those who received a CDR >0 over the follow-up period,although the time to most NPI-Q symptoms was faster for participants who received a CDR >0(p<0.001). With theexception of memory,Geriatric Depression Scale symptoms reported by both CDR groups were similar. Conclusions: We found a significantly earlier presence of positive symptoms on the NPI-Q in cognitively normal patients who subsequently developed CDR >0. Among participants with no depression symptoms at baseline,results suggest that depressive symptoms may increase with aging regardless of incipient dementia. Such findings begin to delineate the noncognitive course of Alzheimer disease dementia in the preclinical stages. Future research must further elucidate the correlation between noncognitive changes and distinct dementia subtypes.

Keywords: non-cognitive symptoms; data set uds; psychological symptoms; csf biomarkers; depression; dementia; prevalence; plaques;centers; tangles

来源出版物:Neurology,2015,84(6): 617-622联系邮箱:Roe,CM; cathyr@wustl.edu

Cytomegalovirus Infection and Risk of Alzheimer Disease in Older Black and White Individuals

Barnes LL; Capuano AW; Aiello AE; et al.

Abstract: Background: Human cytomegalovirus(CMV)is prevalent in older adults and has been implicated in many chronic diseases of aging. This study investigated the relation between CMV and the risk of Alzheimer disease(AD). Methods: Data come from 3 cohort studies that included 849 participants(mean age [+/- SD],78.6 +/- 7.2 years; mean education duration [+/- SD],15.4 +/- 3.3 years; 25% black). Results: A solid-phase enzyme-linked immunosorbent assay was used for detecting type-specific immunoglobulin G antibody responses to CMV and herpes simplex virus type 1(HSV-1)measured in archived serum samples. Of 849 participants,73.4% had serologic evidence of exposure to CMV(89.0% black and 68.2% white; P<0.001). During an average of 5.0 years of follow-up,93 persons developed AD. CMV seropositivity was associated with an increased risk of AD(relative risk,2.15; 95% confidence interval,1.42-3.27)and a faster rate of decline in global cognition(estimate [+/- standard error],-0.02 +/- 0.01; P=0.03)in models that controlled for age,sex,education duration,race,vascular risk factors,vascular diseases,and apolipoprotein epsilon 4 level. Results were similar in black and white individuals for both incident AD and change in cognitive function and were independent of HSV-1 status. Conclusions: These results suggest that CMV infection is associated with an increased risk of AD and a faster rate of cognitive decline in older diverse populations.

Keywords: CMV; Alzheimer’s disease; race; epidemiology

来源出版物:Journal of Infectious Diseases,2015,211(2): 230-237联系邮箱:Barnes,LL; lbarnes1@rush.edu

Asymmetric dimethylarginine exacerbates A beta-induced toxicity and oxidative stress in human cell and Caenorhabditis elegans models of Alzheimer disease

Luo YF; Yue WH; Quan X; et al.

Abstract: Growing evidence suggests a strong association between cardiovascular risk factors and incidence of Alzheimer disease(AD). Asymmetric dimethylarginine(ADMA),the endogenous nitric oxide synthase inhibitor,has been identified as an independent cardiovascular risk factor and is also increased in plasma of patients with AD. However,whether ADMA is involved in the pathogenesis of AD is unknown. In this study,we found that ADMA content was increased in a transgenic Caenorhabditis elegans beta-amyloid(A beta)overexpression model,strain CL2006,and in human SH-SY5Y cells overexpressing the Swedish mutant form of human A beta precursor protein(APPsw). Moreover,ADMA treatment exacerbated A beta-induced paralysis and oxidative stress in CL2006 worms and further elevated oxidative stress and A beta secretion in APPsw cells. Knockdown of type 1 protein arginine N-methyltransferase to reduce ADMA production failed to show a protective effect against A beta toxicity,but resulted in more paralysis in CL2006 worms as well as increased oxidative stress and A beta secretion in APPsw cells. However,overexpression of dimethylarginine dimethylaminohydrolase 1(DDAH1)to promote ADMA degradation significantly attenuated oxidative stress and A beta secretion in APPsw cells. Collectively,our data support the hypothesis that elevated ADMA contributes to the pathogenesis of AD. Our findings suggest that strategies to increase DDAH1 activity in neuronal cells may be a novel approach to attenuating AD development.

Keywords: Alzheimer disease; ADMA; PRMT1; DDAH1; oxidative stress; free radicals

来源出版物:Free Radical Biology and Medicine,2015,79: 117-126联系邮箱:Lu,ZB; luzhongbing@ucas.ac.cn

Effect of Vitamin E and Memantine on Functional Decline in Alzheimer Disease The TEAM-AD VA Cooperative Randomized Trial

Dysken MW; Sano M; Asthana S; et al.

Abstract: IMPORTANCE Although vitamin E and memantine have been shown to have beneficial effects in moderately severe Alzheimer disease(AD),evidence is limited in mild to moderate AD. OBJECTIVE To determine if vitamin E(alpha tocopherol),memantine,or both slow progression of mild to moderate AD in patients taking an acetylcholinesterase inhibitor. DESIGN,SETTING,AND PARTICIPANTS Double-blind,placebo-controlled,parallel-group,randomized clinical trial involving 613 patients with mild to moderate AD initiated in August 2007 and concluded in September 2012 at 14 Veterans Affairs medical centers. INTERVENTIONS Participants received either 2000 IU/d of alpha tocopherol(n=152),20 mg/d of memantine(n=155),the combination(n=154),or placebo(n=152). MAIN OUTCOMES AND MEASURES Alzheimer’s Disease Cooperative Study/Activities of Daily Living(ADCS-ADL)Inventory score(range,0-78). Secondary outcomes included cognitive,neuropsychiatric,functional,and caregiver measures. RESULTS Over the mean(SD)follow-up of 2.27(1.22)years,participants receiving alpha tocopherol had slower decline than those receiving placebo as measured by the ADCS-ADL. The changetranslates into a delay in clinical progression of 19% per year compared with placebo(approximately 6.2 months over the follow-up period). Caregiver time increased least in the alpha tocopherol group. All-cause mortality and safety analyses showed a difference only on the serious adverse event of “infections or infestations” with greater frequencies in the memantine(31 events in 23 participants)and combination groups(44 events in 31 participants)compared with placebo(13 events in 11 participants). [GRAPHICS] CONCLUSIONS AND RELEVANCE Among patients with mild to moderate AD,2000 IU/d of alpha tocopherol compared with placebo resulted in slower functional decline. There were no significant differences in the groups receiving memantine alone or memantine plus alpha tocopherol. These findings suggest benefit of alpha tocopherol in mild to moderate AD by slowing functional decline and decreasing caregiver burden.

Keywords: placebo-controlled trial; nursing-home placement; clinical-trials; co-morbidity; double-blind; moderate; metaanalysis; dementia;supplementation; galantamine

来源出版物:JAMA-Journal of the American Medical Association,2014,311(1): 33-44

联系邮箱:Dysken,MW; maurice.dysken@va.gov

Effect of Citalopram on Agitation in Alzheimer Disease The CitAD Randomized Clinical Trial

Porsteinsson AP; Drye LT; Pollock BG; et al.

Abstract: IMPORTANCE Agitation is common,persistent,and associated with adverse consequences for patients with Alzheimer disease. Pharmacological treatment options,including antipsychotics are not satisfactory. OBJECTIVE The primary objective was to evaluate the efficacy of citalopram for agitation in patients with Alzheimer disease. Key secondary objectives examined effects of citalopram on function,caregiver distress,safety,cognitive safety,and tolerability. DESIGN,SETTING,AND PARTICIPANTS The Citalopram for Agitation in Alzheimer Disease Study(CitAD)was a randomized,placebo-controlled,double-blind,parallel group trial that enrolled 186 patients with probable Alzheimer disease and clinically significant agitation from 8 academic centers in the United States and Canada from August 2009 to January 2013. INTERVENTIONS Participants(n=186)were randomized to receive a psychosocial intervention plus either citalopram(n=94)or placebo(n=92)for 9 weeks. Dosage began at 10 mg per day with planned titration to 30 mg per day over 3 weeks based on response and tolerability. MAIN OUTCOMES AND MEASURES Primary outcome measures were based on scores from the 18-point Neurobehavioral Rating Scale agitation subscale(NBRS-A)and the modified Alzheimer Disease Cooperative Study-Clinical Global Impression of Change(mADCS-CGIC). Other outcomes were based on scores from the Cohen-Mansfield Agitation Inventory(CMAI)and the Neuropsychiatric Inventory(NPI),ability to complete activities of daily living(ADLs),caregiver distress,cognitive safety(based on scores from the 30-point Mini Mental State Examination [MMSE]),and adverse events. RESULTS Participants who received citalopram showed significant improvement compared with those who received placebo on both primary outcome measures. The NBRS-A estimated treatment difference at week 9(citalopram minus placebo)was -0.93(95% CI,-1.80 to -0.06),P=0.04. Results from the mADCS-CGIC showed 40% of citalopram participants having moderate or marked improvement from baseline compared with 26% of placebo recipients,with estimated treatment effect(odds ratio [OR] of being at or better than a given CGIC category)of 2.13(95% CI,1.23-3.69),P=0.01. Participants who received citalopram showed significant improvement on the CMAI,total NPI,and caregiver distress scores but not on the NPI agitation subscale,ADLs,or in less use of rescue lorazepam. Worsening of cognition(-1.05 points; 95% CI,-1.97 to -0.13; P=0.03)and QT interval prolongation(18.1 ms; 95% CI,6.1-30.1; P=0.01)were seen in the citalopram group. CONCLUSIONS AND RELEVANCE Among patients with probable Alzheimer disease and agitation who were receiving psychosocial intervention,the addition of citalopram compared with placebo significantly reduced agitation and caregiver distress; however,cognitive and cardiac adverse effects of citalopram may limit its practical application at the dosage of 30 mg per day.

Keywords: placebo-controlled trials; neuropsychiatric-symptoms; behavioral disturbances; atypical antipsychotics; cache county;double-blind; dementia; outcomes; metaanalysis; multicenter

来源出版物:JAMA-Journal of the American Medical Association,2014,311(7): 682-691

联系邮箱:Porsteinsson,AP; anton_porsteinsson@urmc.rochester.edu

Sleep and Alzheimer disease pathology-a bidirectional relationship

Ju YES; Lucey BP; Holtzman DM

Abstract: Factors other than age and genetics may increase the risk of developing Alzheimer disease(AD). Accumulation of the amyloid-beta(A beta)peptide in the brain seems to initiate a cascade of key events in the pathogenesis of AD. Moreover,evidence is emerging that the sleep-wake cycle directly influences levels of A beta in the brain. In experimental models,sleep deprivation increases the concentration of soluble A beta and results in chronic accumulation of A beta,whereas sleep extension has the opposite effect. Furthermore,once A beta accumulates,increased wakefulness and altered sleep patterns develop. Individuals with early A beta deposition who still have normal cognitive function report sleep abnormalities,as do individuals with very mild dementia due to AD. Thus,sleep and neurodegenerative disease may influence each other in many ways that have important implications for the diagnosis and treatment of AD.

Keywords: mild cognitive impairment; default mode network; suprachiasmatic nucleus; circadian-rhythms; beta dynamics; older women;wake cycle; in-vivo; dementia; age

来源出版物:Nature Reviews Neurology,2014,10(2): 115-119联系邮箱:Holtzman,DM; holtzman@neuro.wustl.edu

Variants in the ATP-Binding Cassette Transporter(ABCA7),Apolipoprotein E epsilon 4,and the Risk of Late-Onset Alzheimer Disease in African Americans

Reitz C; Jun G; Naj A; et al.

Abstract: Importance: Genetic variants associated with susceptibility to late-onset Alzheimer disease are known for individuals of European ancestry,but whether the same or different variants account for the genetic risk of Alzheimer disease in African American individuals is unknown. Identification of disease-associated variants helps identify targets for genetic testing,prevention,and treatment. Objective: To identify genetic loci associated with late-onset Alzheimer disease in African Americans. Design,Setting,and Participants: The Alzheimer Disease Genetics Consortium(ADGC)assembled multiple data sets representing a total of 5896 African Americans(1968 case participants,3928 control participants)60 years or older that were collected between 1989 and 2011 at multiple sites. The association of Alzheimer disease with genotyped and imputed single-nucleotide polymorphisms(SNPs)was assessed in case-control and in family-based data sets. Results from individual data sets were combined to perform an inverse variance-weighted meta-analysis,first with genome-wide analyses and subsequently with gene-based tests for previously reported loci. Main Outcomes and Measures: Presence of Alzheimer disease according to standardized criteria. Results: Genome-wide significance in fully adjusted models(sex,age,APOE genotype,population stratification)was observed for a SNP in ABCA7(rs115550680,allele=G; frequency,0.09 cases and 0.06 controls; odds ratio [OR],1.79 [95% CI,1.47-2.12];P=2.2×10-9,which is in linkage disequilibrium with SNPs previously associated with Alzheimer disease in Europeans(0.8<D'<0.9). The effect size for the SNP in ABCA7 was comparable with that of the APOE epsilon 4-determining SNP rs429358(allele=C; frequency,0.30 cases and 0.18 controls; OR,2.31 [95% CI,2.19-2.42]; P=5.5×10-47. Several loci previously associated with Alzheimer disease but not reaching significance in genome-wide analyses were replicated in gene-based analyses accounting for linkage disequilibrium between markers and correcting for number of tests performed per gene(CR1,BIN1,EPHA1,CD33; 0.0005<empirical P<0.001). Conclusions and Relevance: In this meta-analysis of data from African American participants,Alzheimer disease was significantly associated with variants in ABCA7 and with other genes that have been associated with Alzheimer disease in individuals of European ancestry. Replication and functional validation of this finding is needed before this information is used in clinical settings.

Keywords: genome-wide association; mild cognitive impairment; identifies variants; parkinson disease; common variants; e genotype;dementia; metaanalysis; loci; CLU

来源出版物:JAMA-Journal of The American Medical Association,2013,309(14): 1483-1492联系邮箱:Mayeux,R; rpm2@columbia.edu

OPINION Preclinical Alzheimer disease-the challenges ahead

Sperling RA; Karlawish J; Johnson KA; et al.

Abstract: There is growing recognition that the pathophysiological process of Alzheimer disease(AD)begins many years prior to clinically obvious symptoms,and the concept of a presymptomatic or preclinical stage of AD is becoming more widely accepted. Advances in biomarker studies have enabled detection of AD pathology in vivo in clinically normal older individuals. The predictive value of these biomarkers at the individual patient level,however,remains to be elucidated. The ultimate goal of identifying individuals in the preclinical stages of AD is to facilitate early intervention to delay and perhaps even prevent emergence of the clinical syndrome. A number of challenges remain to be overcome before this concept can be validated and translated into clinical practice.

Keywords: amyloid-beta; clinical decline; risk; association; cognition; adults; recommendations; abnormalities; prediction; biomarkers

来源出版物:Nature Reviews Neurology,2013,9(1): 54-58联系邮箱:Sperling,RA; reisa@rics.bwh.harvard.edu

A blood based 12-miRNA signature of Alzheimer disease patients

Leidinger P; Backes C; Deutscher S; et al.

Abstract: Background: Alzheimer disease(AD)is the most common form of dementia but the identification of reliable,early and non-invasive biomarkers remains a major challenge. We present a novel miRNA-based signature for detecting AD from blood samples. Results: We apply next-generation sequencing to miRNAs from blood samples of 48 AD patients and 22 unaffected controls,yielding a total of 140 unique mature miRNAs with significantly changed expression levels. Of these,82 have higher and 58 have lower abundance in AD patient samples. We selected a panel of 12 miRNAs for an RT-qPCR analysis on a larger cohort of 202 samples,comprising not only AD patients and healthy controls but also patients with other CNS illnesses. These included mild cognitive impairment,which is assumed to represent a transitional period before the development of AD,as well as multiple sclerosis,Parkinson disease,major depression,bipolar disorder and schizophrenia. miRNA target enrichment analysis of the selected 12 miRNAs indicates an involvement of miRNAs in nervous system development,neuron projection,neuron projection development and neuron projection morphogenesis. Using this 12-miRNA signature,we differentiate between AD and controls with an accuracy of 93%,a specificity of 95% and a sensitivity of 92%. The differentiation of AD from other neurological diseases is possible with accuracies between 74% and 78%. The differentiation of the other CNS disorders from controls yields even higher accuracies. Conclusions: The data indicate that deregulated miRNAs in blood might be used as biomarkers in the diagnosis of AD or other neurological diseases.

Keywords: Alzheimer disease; miRNA; biomarker; next-generation sequencing; quantitative Real Time PCR

来源出版物:Genome Biology,2013,14(7): Art. No. R78联系邮箱:Keller,A,keller.andreas@siemens.com

编辑:王微,王帅帅

Necropsy brain tissue from normal(control)patients and patients with depression and dementia was examined for activities of various cholinergic components,and these related to the degree of senile plaque formation and extent of intellectual impairment. Choline acetyltransferase and acetylcholinesterase activities decreased significantly as the mean plaque count rose,and in depressed and demented subjects the reduction in choline acetyltransferase activity correlated with the extent of intellectual impairment as measured by a memory information test; muscarinic cholinergic receptor binding activity remained unchanged with increasing senile plaque formation but butyrylcholinesterase activity increased. The results suggest a close relation between changes in the cholinergic system and Alzheimer's dementia,but the precise role of the system in this disease remains to be elucidated.

linkage; locus; chromosome-14; protein

高影响力文章

文献编号文章题目第一作者来源出版物1Correlation of cholinergic abnormalities with senile plaques and mental test-scores in senile dementiaPerry EKBritish Medical Journal,1978,2(6150):1457-1459 2 Clinical-diagnosis of Alzheimers-disease - report of the nincds-adrda work group under the auspices of department-of-health-and-human-services task-force on Alzheimers-disease Mckhann GNeurology,1984,34(7): 939-944 3 Alzheimers-disease - initial report of the purification and characterization of a novel cerebrovascular amyloid protein Glenner GGBiochemical and Biophysical Research Communications,1984,120(3): 885-890 Proceedings of the National Academy of Sciences of the United States of America,1985,82(12): 4245-4249 5The precursor of Alzheimers-disease amyloid-a4 protein resembles a cell-surface receptorKang JNature,1987,325(6106): 733-736 4Amyloid plaque core protein in Alzheimer-disease and down syndrome Masters CL

Correlation of cholinergic abnormalities with senile plaques and mental test-scores in senile dementia

Perry EK; Tomlinson BE; Blessed G; et al.

*摘编自《深圳大学学报(理工版)》2013年30卷4期331~348页,图、表、参考文献已省略。

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