阿尔茨海默病病因学研究进展及治疗展望

阿尔茨海默病(Alzheimer disease，AD)是老年人中最常见的神经退行性疾病之一。它的临床特点是隐匿起病，逐渐出现记忆力减退、认知功能障碍、行为异常和社交障碍。通常病情进行性加重，在2～3年内丧失独立生活能力，10～20年左右因并发症而死亡。AD的病理特征：脑神经细胞外出现β-淀粉样肽(Ap)聚集形成的神经斑或称老年斑、脑神经     

内质网应激与Alzheimer病

Alzheimer病(Alzheimer’s disease,AD)是老年人常见的神经系统变性病,其临床特点是隐匿起病,病情进行性加重,出现认知障碍和行为异常。病理特点为脑神经细胞外出现β淀粉样肽(Aβ)聚集形成的神经斑或称老年斑、脑神经细胞内tau蛋白异常聚集形成神经原纤维缠结(NFT)、脑皮质神经细胞减少及皮质动脉和小动脉的血管淀粉样变性。AD的病因学和发病机制尚不清楚,但已有许多假说,如Aβ产物过多、tau蛋白的异常磷酸化、过氧化作用、炎症因素、金属与细胞内钙紊乱、遗传因素等[1]。近年来因蛋白质折叠障碍造成的异常蛋白质的聚集在神经变性疾病…     

阿尔茨海默病炎症发病机制的研究进展

阿尔茨海默病(Alzheimer disease，AD)是一种常见的老年神经变性疾病，临床上表现为进行性认知功能障碍和精神异常。其病理特征为：神经元外的β-淀粉样蛋白(Aβ)聚集形成老年斑(senile plaques，SP)。神经元内tau蛋白异常聚集形成神经纤维缠结(neurofibrillary tangles，NFTs)，脑皮质、海马胆碱能神经元及其突触大量丢失。累及的皮层动脉和小动     

细胞凋亡及与线粒体电压依赖性阴离子通道1的联系在阿尔茨海默病中的研究进展

正阿尔茨海默病(Alzheimer’s disease,AD)是一种以进行性认知功能下降和行为能力受损为特征的中枢神经系统退行性疾病。病理特征主要表现为β-淀粉样蛋白(Aβ)聚集形成老年斑及微管相关蛋白tau蛋白异常高度磷酸化导致神经原纤维缠结(NFTs),也包括突触细胞丢失、     

髓样细胞触发受体2调控小胶质细胞功能及参与阿尔茨海默病发病机制的研究进展

阿尔茨海默病(AD)是一种以细胞外β淀粉样蛋白(Aβ)沉积形成的淀粉样斑块、细胞内过度磷酸化tau蛋白形成的纤维缠结及神经炎症为特征性病理表现的神经退行性病变。近年来研究发现,髓样细胞触发受体2(TREM2)基因突变显著增加阿尔茨海默病的发病风险。TREM2在中枢神经系统(CNS)中仅表达于小胶质细胞,小胶质细胞作为CNS中最主要的一道免疫防线,吞噬中枢神经系统特异性碎片及Aβ和tau等异常聚集蛋白,还可调节可溶性炎症介质的释放,以应对中枢神经系统损伤。本文对小胶质细胞TREM2在AD中的作用进行综述。     

髓样细胞触发受体 2与阿尔茨海默病关系的研究进展

阿尔茨海默病(AD)是老年期痴呆最常见的类型,是一种复杂的、不可逆的神经退行性疾病.其特征性的病理改变是细胞外出现β淀粉样蛋白(Aβ)沉积形成的淀粉样斑块(SP)、细胞内过度磷酸化的tau蛋白形成的纤维缠结及显著的突触丢失、脑萎缩和神经元细胞的死亡.     

阿尔茨海默病新型免疫治疗方法

阿尔茨海默病为世界范围内的痴呆常见类型,是目前全球关注的健康热点问题。针对β-淀粉样蛋白(Aβ)沉积和过度磷酸化tau蛋白聚集的内在生物化学机制已有深入研究,来源于正常可溶性Aβ肽的Aβ寡聚体被认为最具毒性。然而,纤维状Aβ聚集形成淀粉样斑块和淀粉样脑血管病是阿尔茨海默病的主要病理改变;而异常磷酸化tau蛋白沉积并形成可溶性毒性寡聚体,进而聚集成为神经原纤维缠结,则是其另一重要病理特征。目前,已有许多措施用于抑制、清除或减缓阿尔茨海默病淀粉样斑块的病理进程,而免疫治疗是这一领域中的新的突破。针对Aβ沉积阿尔茨海默病动物模型进行的主动和被动免疫治疗,已取得重大研究成果。然而,临床试验仅有极少数据显示出明确的疗效,究其原因在于免疫治疗引起的并发症。主动免疫实验引起的脑炎,以及被动免疫治疗在少数人群中诱发的血管源性水肿或淀粉样蛋白相关显像异常已有相关报道。迄今为止,单纯针对tau蛋白聚集的治疗仍然仅局限于小鼠模型,鲜有研究同时针对Aβ沉积和tau蛋白聚集两种病理特征。到目前为止,大部分免疫治疗均以自身蛋白为靶向,尽管其构造异常,在取得疗效的同时,需防止引起过度毒性炎症反应的可能。为取得更好的疗效,未来的免疫治疗应集中在毒性寡聚体,并以阿尔茨海默病的所有病理特征为靶向。     

丁酰胆碱酯酶在阿尔茨海默病发病机制中的作用

阿尔茨海默病是一种病因和发病机制尚未明确的神经变性病,其典型病理改变为β-淀粉样蛋白沉积形成的神经炎性斑(亦称老年斑)和tau蛋白异常聚集形成的神经原纤维缠结,常累及胆碱能系统,其中丁酰胆碱酯酶在阿尔茨海默病发病与进展过程中发挥重要作用。本文就丁酰胆碱酯酶在阿尔茨海默病发病机制中的作用进行简要综述。     

以β淀粉样蛋白为靶点治疗阿尔茨海默病的研究进展

阿尔茨海默病是导致老年人认知功能障碍最常见的一种中枢神经系统退行性疾病。由于阿尔茨海默病发病机制的复杂性,目前针对阿尔茨海默病可采用的治疗方法有限。淀粉样蛋白假说认为β淀粉样蛋白聚集是导致阿尔茨海默病一系列病理生理改变的中心触发因素,文中以β淀粉样蛋白为靶点通过多种机制治疗阿尔茨海默病的相关研究进行综述。     

以β淀粉样蛋白为靶点治疗阿尔茨海默病的临床药物试验研究进展

β淀粉样蛋白(Aβ)所形成的斑块沉积是阿尔茨海默病(AD)的重要病理特征之一。Aβ的聚集对神经细胞具有毒性作用,可导致海马及皮质神经元的变性和死亡,最终造成机体学习记忆及认知功能障碍。以Aβ为治疗靶点,减少Aβ斑块的生成和促进其清除,是目前治疗AD,改善认知功能障碍的主要策略之一,并已有多种靶向药物进入临床药物试验。本文将近年的相关临床药物试验研究进展作了综述。     

Denervation study of synapses of organ of corti of old world monkeys

Fine structural characteristics of synapses in the spiral organ of Corti were examined, with reference to differences between inner and outer haircell systems, and to location of neurons of origin of efferent axons. Surgical interruption of crossed olivocochlear bundle, of vestibular nerve, of facial nerve, and excision of superior cervical ganglia were used to determine the pathways of efferent axons. Interruption of the vestibular nerve near the brainstem results in degeneration of all efferent terminals on outer hair cells. Mid-line lesions at, and caudal to, the facial colliculus result in degeneration of about half of these efferent terminals. Efferent synaptic bulbs to the inner hair-cell system are small, of the order of one micron, and form type 2 junctions with afferent dendrites. They tend to have more large dense-core vesicles (about 80 nm) than the large efferent terminals of the outer hair-cell system, and appear to be the terminals of axons in the habenula perforata, which exhibit varicosities laden with large dense core vesicles. The varicosities are unaffected by excision of the superior cervical ganglia. So far as our material can reveal, it appears that the varicosities in the habenula perforata do not survive vestibular root interruption, nor do the efferent processes in the internal spiral bundle or at the base of inner hair cells. Most interestingly, the afferent processes of the inner hair-cell system, as identified for example by their relation to pre-synaptic bodies in the inner hair cells, are subject to a trans-synaptic reaction after severance of the vestibular root. They undergo a dramatic cytological transformation, characterized by increase of volume, engorgement with microtubules, microfilaments, microvesicles of various sizes, and clusters of lysosomes. Thus, both the efferent and afferent terminals of the inner hair-cell system show marked cytological differences from the corresponding terminals of the outer hair cell system.     

Mechanism of action of tubocurarine on nicotinic cholinoreceptors of neurons of the sympathetic ganglia of rats

Tubocurarine (Tc) effect on membrane currents elicited by acetylcholine (ACh) was studied in isolated superior cervical ganglion neurons of rat using patch-clamp method in the whole-cell recording mode. The "use-dependent" block of ACh current by Tc was revealed in the experiments with ACh applications, indicating that Tc blocked the channels opened by ACh. Mean lifetime of Tc-open channel complex, tau, was found to be 9.8 +/- 0.5 s (n = 7) at -50 mV and 20-24 degrees C. tau exponentially increased with membrane hyperpolarization (e-fold change in tau corresponded to the membrane potential shift by 61 mV). Inhibition of the ACh-induced current by Tc (3-30 microM/1) was completely abolished by membrane depolarization to the level of 80-100 mV. Inhibition of ACh-induced current was augmented at increased ACh doses. It is concluded that the open channel block produced by Tc is likely to be the only mechanism for Tc action on nicotinic acetylcholine receptors in superior cervical ganglion neurons of rat.     

The effect of age of onset of PD on risk of dementia

Background Dementia occurs in the majority of patients with Parkinson’s disease (PD). Late onset of PD has been reported to be associated with a higher risk for dementia. However, age at onset (AAO) and age at baseline assessment are often correlated. The aim of this study was to explore whether AAO of PD symptoms is a risk factor for dementia independent of the general effect of age. Methods Two community-based studies of PD in New York (n = 281) and Rogaland county, Norway (n = 227) and two population-based groups of healthy elderly from New York (n = 180) and Odense, Denmark (n = 2414) were followed prospectively for 3–4 years and assessed for dementia according to DSM-IIIR. All PD and control cases underwent neurological examination and were followed with neurological and neuropsychological assessments. We used Cox proportional hazards regression based on three different time scales to explore the effect of AAO of PD on risk of dementia, adjusting for age at baseline and other demographic and clinical variables. Findings In both PD groups and in the pooled analyses, there was a significant effect of age at baseline assessment on the time to develop dementia, but there was no effect of AAO independent of age itself. Consistent with these results, there was no increased relative effect of age on the time to develop dementia in PD cases compared with controls. Interpretation This study shows that it is the general effect of age, rather than AAO that is associated with incident dementia in subjects with PD. Received in revised form: 22 December 2005     

Limits of deinstitutionalization--perspectives of relatives of psychiatric patients

After a hopeful beginning, the social process of the reintegration of those with severe mental illness has come to a standstill. I am led to wonder whether "the community" really wants to live together with people suffering from severe mental illness, and if so, how closely? As long as the medical treatment of mental illness provided by the general practitioners is fundamentally deficient, as they are not able to prescribe the necessary interventions--such as out-patient psychiatric nursing, and service providers in the out-patient sector are content with offering increasingly intensive forms of care for the less seriously ill at the cost of the Social Welfare System--the reintegration of those with serious mental illness remains an illusion--which is mainly to the benefit of providers of residential care in homes and hostels.