β淀粉样蛋白在阿尔茨海默病发病中的相关性研究

阿尔茨海默病(AD)是一种常见的中枢神经系统退行性疾病,β淀粉样蛋白(Aβ)在AD的发生和发展中起着关键性作用,Aβ沉积可引起突触和线粒体结构及功能的一系列改变,研究Aβ在AD发病中的作用及相关性,对AD的治疗有指导意义。     

脑啡肽酶(Neprilysin)与老年痴呆

阿尔茨海默氏病(Alzheimer's disease,AD)是一种多发生在老年的中枢神经系统退行性疾病。其发病机制尚未阐明。细胞外淀粉样β蛋白(amyloidβ-protein,Aβ)沉积是AD主要病理学特征之一。体内Aβ的稳态水平取决于Aβ合成和分解活动之间的代谢平衡。几乎在所有家族性AD中,Aβ合成代谢增加被认为是引起Aβ沉积的主要原因,但在散发AD中较少证据支持Aβ生成增多的作用。因此,近年来Aβ降解减少在AD中的作用逐渐引起人们的重视。与Aβ降解有关的酶也得到了广泛的研究。Neprilysin(NEP),也称脑啡肽酶。本世纪以来,它在Aβ分解代谢中的作…     

阿尔茨海默病中β-淀粉样蛋白异常沉积机制的研究进展

近年研究发现, AD中神经元受损事件要先于β-淀粉样蛋白(Aβ)的异常沉积, Aβ斑块可能并不是AD发病的直接病因, 而只是AD发病后的病理表现, 但是Aβ异常沉积与AD联系紧密, 因此探讨AD中Aβ的异常沉积机制对于AD的早期诊治仍具有重要意义。Aβ的异常沉积已被证实与自噬功能障碍、细胞焦亡、铁死亡和脑膜淋巴管(Mlvs)回流障碍密切相关, 故本文现围绕上述病理过程对AD发生中Aβ斑块异常沉积的作用综述如下, 以期寻找新的AD干预靶点。     

阿尔茨海默病患者脑脊液中葡萄糖、真胰岛素、Aβ_(40)和Aβ_(42)测定

目的检测阿尔茨海默病(AD)患者脑脊液中葡萄糖、真胰岛素、Aβ40和Aβ42水平,探讨AD患者脑内胰岛素及β淀粉样蛋白(Aβ)相关性。方法随机选取35例对照组、48例AD患者,检验其脑脊液中葡萄糖、真胰岛素、Aβ40和Aβ42水平,将AD按轻、中重度分组后与对照组进行比较。结果AD患者各组脑脊液中葡萄糖与相应对照组比较,无显著性差异(P>0.05);AD各组Aβ40与对照组相比,无显著性差异(P>0.05);轻度AD组脑脊液真胰岛素与对照组比较,无显著性差异(P>0.05),中重度AD组真胰岛素较对照组降低,有显著性差异(P<0.05);AD组、轻度AD组Aβ42较对照组降低,有显著性差异(P<0.01);中重度AD组Aβ42较对照组降低,有极显著性差异(P<0.001)。结论AD患者脑脊液中胰岛素和Aβ42异常情况,与疾病的严重程度相关。     

β淀粉样蛋白代谢相关基因与阿尔茨海默病的研究进展

阿尔茨海默病(AD)是老年人常见的神经系统变性疾病,是痴呆中最常见的一种类型,目前认为β淀粉样蛋白(Aβ)的异常沉积是AD主要发病机制之一,然而,Aβ的异常沉积与Aβ代谢相关基因的表达异常密切相关。本文就Aβ代谢相关基因作一综述,并讨论其在AD早期诊断中的意义。     

阿尔茨海默病中的Aβ研究进展

近年来由于分子生物学技术的应用推动了AD的病因研究 ,发现了几个AD的相关基因 ,其中最重要的是APP基因 ,由于APP蛋白断裂后产生具有毒性作用的Aβ。目前有许多研究者认为Aβ是AD的发病直接原因 ,本文就AD中的Aβ研究进展作一简要综述。     

基于清除β淀粉样蛋白在治疗阿尔茨海默病的研究进展

阿尔茨海默病（Alzheimer’s disease,AD）是最常见的神经退行性疾病,AD的病理蛋白主要包括β-淀粉样蛋白（Aβ）和Tau,了解Aβ的生成和清除途径对于延缓甚至阻止AD是至关重要的。由于目前尚无有效干预手段,处于研究中的治疗方法非常多,针对Aβ的研究最为热门,本文将阐述Aβ生成及代谢,介绍目前关于Aβ的治疗方法的研究,分析通过促进外周代谢途径来减少脑中Aβ的浓度的治疗方法,为AD的治疗提供新思路。     

尿激酶型纤溶酶原激活剂基因多态性与散发性阿尔茨海默病的相关性

阿尔茨海默病（Alzheimer’s disease，AD）最具特征的病理改变是大量老年斑形成^[1]，老年斑的主要成分是β淀粉样蛋白（β-amyloid protein，Aβ）。AD的病程一般从Aβ在脑中沉积开始，一方面是由于Aβ合成增多，另一方面是由于Aβ降解减少。Aβ合成和降解的平衡在AD的发病中起着重要的作用。既往的研究主要是探究Aβ合成增多的原因，新近的研究表明，     

干预Aβ代谢及其毒性治疗AD的研究现状及展望

阿尔茨海默病（AD）是老年痴呆最常见的原因,发病机制尚不清楚。近代研究提示,β淀粉样蛋白（Aβ）异常聚集及其神经毒性是AD的主要发病机制之一,因此如何减少Aβ在脑内聚集以及降低其毒心已成为治疗AD的主要措施之一,本文针对干预Aβ代谢及其神经毒性治疗AD的研究作一综述。     

β淀粉样蛋白致神经细胞凋亡机制的研究进展

阿尔茨海默病（AD）是老年期痴呆最主要类型。β淀粉样蛋白（Aβ）可诱导神经细胞凋亡，是AD发生发展的关键因素。近年来，Aβ的神经毒性及其产生机制一直是对AD研究的热点问题，Aβ导致体外培养的神经细胞凋亡的可能机制包括氧化应激和钙稳态失衡，NF-κB基因调控，糖原合酶激酶3β和细胞周期依赖性激酶的活动等，这些机制的阐明对揭示AD发病原因及探索有效防治措施具有重要意义。     

Environmental factors in the development and progression of late-onset Alzheimer＇s disease

Late-onset Alzheimer＇s disease （LOAD） is an age-related neurodegenerative disorder characterized by gradual loss of synapses and neurons, but its pathogenesis remains to be clarified. Neurons live in an environment constituted by neurons themselves and glial cells. In this review, we propose that the neuronal degeneration in the AD brain is partially caused by diverse environmental factors. We first discuss various environmental stresses and the corresponding responses at different levels. Then we propose some mechanisms underlying the specific pathological changes, in particular, hypothalamic-pituitary adrenal axis dysfunction at the systemic level; cerebrovascular dysfunction, metal toxicity, glial activation, and Aβ toxicity at the intercellular level; and kinase-phosphatase imbalance and epigenetic modification at the intracellular level. Finally, we discuss the possibility of developing new strategies for the prevention and treatment of LOAD from the perspective of environmental stress. We conclude that environmental factors play a significant role in the development of LOAD through multiple pathological mechanisms.     

Total saponins of Panax ginseng effects on proliferation and differentiation of human embryonic neural stem cells and in a Parkinson’s disease mouse model

BACKGROUND： Total saponins of Panax ginseng （TSPG） exhibits neuroprotection against Parkinson＇s disease in the substantia nigra. OBJECTIVE： To investigate the effects of TSPG on human embryonic neural stem cells （NSCs） proliferation and differentiation into dopaminergic neurons using in vitro studies, and to observe NSC differentiation in a mouse model of Parkinson＇s disease, as well as behavioral changes before and after transplantation. DESIGN, TIME AND SETTING： In vitro neural cell biology trial and in vivo randomized, controlled animal trial were performed at the Institute of Basic Medical Sciences, Chongqing Medical University between September 2004 and December 2007. MATERIALS： TSPG （purity 〉 95%） was isolated, extracted, and identified by Chongqing Academy of Chinese Materia Medica. Recombinant human basic fibroblast growth factor （bFGF） and recombinant human epidermal growth factor （EGF） were purchased from PeproTech, USA. A total of 25 C57/BL6J mice, aged 18-20 weeks were included. Twenty were used to establish a Parkinson＇s disease model with i.p. injection of MPTP （1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine） and TSPG alone or combined with interleukin-1 （IL-1）-treated NSCs prior to transplantation into the corpus striatum. The remaining five mice were pretreated for 3 days with TSPG prior to MPTP injection, serving as the TSPG prevention group. METHODS： Primary NSCs were isolated, cultured and purified from embryonic cerebral cortex. Immunocytochemistry was employed to detect specific antigen expression in the NSCs. In vitro experiment： （1） to induce proliferation, NSCs were treated with TSPG, EGF＋bFGF, or TSPG＋EGF＋bFGF, respectively; （2） to induce dopaminergic neuronal differentiation, NSCs were treated with TSPG, IL-1, or TSPG＋IL-1, respectively. MAIN OUTCOME MEASURES： In vitro experiment： the effects of TSPG on NSCs proliferation were evaluated with flow cytometry and MTT assay. Tyrosine hydroxylase expression was determined by immunocytochemistry assay to observe effects of TSPG on dopaminergic neuronal differentiation. In vivo experiment： differentiation of grafted NSCs in the mouse brain was determined by immunohistochemical staining. Behavioral changes were evaluated by spontaneous activity frequency, memory function, and score of paralysis agitans. RESULTS： （1） NSCs were cultured and passaged for more than three passages. Immunocytochemistry revealed positive nestin staining, as well as neurofilament protein and glial fibrillary acidic protein. （2） TSPG significantly increased NSC proliferation, in particular when combined with EGF and bFGF, which was twice as effective as FGF or bFGF alone. TSPG also induced dopaminergic differentiation in NSCs, in particular when TSPG was added together with IL-1, resulting in an effect five times greater than that of IL-1 alone. （3） At day 30 following transplantation, most NSCs in the TSPG prevention group differentiated into dopaminergic neurons, and the scores of paralysis agitans, spontaneous activity, and memory function were significantly increased compared with TSPG alone or TSPG＋IL-1 groups （P 〈 0.05）. CONCLUSION： TSPG stimulated NSC proliferation, in particular when combined with FGF and bFGF. TSPG significantly induced dopaminergic neuronal differentiation of NSCs, and the effect was greater when combined with IL-1. In addition, TSPG greatly improved behavior in the Parkinson＇s disease mouse model following NSC transplantation. Following NSC transplantation, TSPG pretreatment exhibited superior efficacy over either TSPG alone or TSPG in combination with IL-1, in terms of behavioral improvements in the Parkinson＇s disease mouse model.     

阿尔茨海默病治疗的研究进展

阿尔茨海默病（AD）是一种隐匿性起病,进行性恶化的神经退行性疾病,临床最初表现为认知功能障碍,并有可能在5～10年内完全衰退。患者往往伴随严重的记忆力丧失、精神行为异常、人格改变、言语功能障碍,无法独立生活,最终近乎于植物状态。Ferri等采用DISMOD软件在全球60岁以上人群中估计,全球的痴呆患者人数到2040年将达到8llO万左右。     

缺氧与阿尔茨海默病:低氧诱导因子-1的作用

阿尔茨海默病(Alzheimer's disease,AD)是最常见的老年神经变性疾病,其临床诊疗重视“早期发现、早期诊断、早期治疗”.体液或脑内有特定的AD生化、病理等改变,但未出现临床症状的AD称为临床前期阿尔茨海默病(Preclinical AD,PCAD).确定PCAD的危险因素,并进行早期干预对AD的防治有重要意义.缺氧是临床上常见的疾病病理过程,也是AD等多种神经变性疾病的重要危险因素.缺氧导致AD或促进AD病程进展的可能机制受到了广泛的关注和研究,本文就缺氧导致β-淀粉样蛋白(Aβ)沉积、tau蛋白异常磷酸化和神经元变性死亡的机制进行了综述,着重讨论了低氧诱导因子(hypoxia inducible factor 1,HIF-1)在其中的复杂作用.     

Neuronal failure in Alzheimer＇s disease： a view through the oxidative stress looking-glass

Considerable debate and controversy surround the cause（s） of AIzheimer＇s disease （AD）. To date, several theories have gained notoriety, however none is universally accepted. In this review, we provide evidence for the oxidative stress-induced AD cascade that posits aged mitochondria as the critical origin of neurodegeneration in AD.     

Dysfunctional autophagy in Alzheimer＇s disease： pathogenic roles and therapeutic implications

Neuronal autophagy is essential for neuronal survival and the maintenance of neuronal homeostasis. Increasing evidence has implicated autophagic dysfunction in the pathogenesis of Alzheimer＇s disease （AD）. The mechanisms underlying autophagic failure in AD involve several steps, from autophagosome formation to degradation. The effect of modulating autophagy is context-dependent. Stimulation of autophagy is not always beneficial. During the implementation of therapies that modulate autophagy, the nature of the autophagic defect, the timing of intervention, and the optimal level and duration of modulation should be fully considered.     

Oxidative stress in Alzheimer＇s disease

Oxidative stress plays a significant role in the pathogenesis of Alzheimer＇s disease （AD）, a devastating disease of the elderly. The brain is more vulnerable than other organs to oxidative stress, and most of the components of neurons （lipids, proteins, and nucleic acids） can be oxidized in AD due to mitochondrial dysfunction, increased metal levels, inflammation, and β-amyloid （Aβ） peptides. Oxidative stress participates in the development of AD by promoting Aβ deposition, tau hyperphosphorylation, and the subsequent loss of synapses and neurons. The relationship between oxidative stress and AD suggests that oxidative stress is an essential part of the pathological process, and antioxidants may be useful for AD treatment.     

M1 muscarinic acetylcholine receptor in Alzheimer＇s disease

The degeneration of cholinergic neurons and cholinergic hypofunction are pathologies associated with Alzheimer＇s disease （AD）. Muscarinic acetylcholine receptors （mAChRs） mediate acetylcholine-induced neurotransmission and five mAChR subtypes （M1-M5） have been identified. Among them, M1 mAChR is widely expressed in the central nervous system and has been implicated in many physiological and pathological brain functions. In addition, M1 mAChR is postulated to be an important therapeutic target for AD and several other neurodegenerative diseases. In this article, we review recent progress in understanding the functional involvement of M1 mAChR in AD pathology and in developing M1 mAChR agonists forAD treatment.     

Cerebrospinal fluid biomarkers of Alzheimer＇s disease

Alzheimer＇s disease （AD） is a fatal neurodegenerative disorder that takes about a decade to develop, making early diagnosis possible. Clinically, the diagnosis of AD is complicated, costly, and inaccurate, so it is urgent to find specific biomarkers. Due to its multifactorial nature, a panel of biomarkers for the multiple pathologies of AD, such as cerebral amyloidogenesis, neuronal dysfunction, synapse loss, oxidative stress, and inflammation, are most promising for accurate diagnosis. Highly sensitive and high-throughput proteomic techniques can be applied to develop a panel of novel biomarkers for AD. In this review, we discuss the metabolism and diagnostic performance of the well-established core candidate cerebrospinal fluid （CSF） biomarkers （β-amyloid, total tau, and hyperphosphorylated tau）. Meanwhile, novel promising CSF biomarkers, especially those identified by proteomics, updated in the last five years are also extensively discussed. Furthermore, we provide perspectives on how biomarker discovery for AD is evolving.     

Effects of natural-cerebrolysin-containing serum on neurotoxicity and synaptogenesis in amyloid-beta 1-40-induced Alzheimer’s disease in vitro models

BACKGROUND： Neuronal loss, synapse mutilation, and increasing malnourished axons are pathologically related to Alzheimer＇s disease. Microtubule-associated protein 2 （MAP2） is of importance for neuronal, axonal, and dendritic generation, extension, and stabilization, as well as for the regulation of synaptic plasticity.
OBJECTIVE： To investigate the antagonistic effects of natural-cerebrolysin-containing serum on beta amyloid protein 1-40 （Aβ1-40）-induced neurotoxicity from the standpoints of cell proliferation, synaptogenesis, and cytoskeleton formation （MAP2 expression）. DESIGN, TIME AND SETTING： A paralleled, controlled, neural cell, and molecular biology experiment was performed at the Institute of Integrated Chinese and Western Medicine, Shenzhen Hospital, Southern Medical University between February 2006 and April 2008.
MATERIALS： PC12 cells, derived from the rat central nervous system, were purchased from Shanghai Institute of Cell Biology, Chinese Academy of Sciences, China. A β1-40 was provided by Sigma, USA. Natural-cerebrolysin was provided by Shenzhen Institute of Integrated Chinese and Western Medicine, China. The natural-cerebrolysin was predominantly composed of Renshen （Radix Ginseng）, Tianma （Rhizoma Gastrodiae）, and Yixingye （Ginkgo Leaf） in a proportion of 1：2：2. Following conventional water extraction technology, an extract （1：20） was prepared. Each gram of extract equaled 20 grams of crude drug. In a total of 12 adult male New Zealand rabbits, six underwent intragastric administration of natural-cerebrolysin extract for 1 month to prepare natural-cerebrolysin-containing serum, and the remaining six rabbits received intragastric administration of physiological saline to prepare normal blank serum.
METHODS： An AIzheimer＇s disease in vitro model was induced in PC12 cells using Aβ1-40. The cells were incubated with varying doses of natural-cerebrolysin-containing serum （2.5%, 5%, and 10%）. Normal blank serum-treated PC12 cells served as a blank control group.
MAIN OUTCOME MEASURES： Through the use of inverted phase contrast microscope, cell morphology and neurite growth were observed, neurite length was measured, and the percentage of neurite-positive cells was calculated. Cell proliferation rate was determined by MTT assay, and MAP 2 expression was detected by fluorescent immunocytochemistry.
RESULTS： Following Aβ1-40 treatments, some PC12 cells were apoptotic/dying, and only a few short neurites were observed. Following interventions with natural-cerebrolysin-containing serum, the PC12 cells proliferated, there was an increased number of neurites, and neurite length was enhanced. After middle- and high-dose natural-cerebrolysin treatments, the percentage of neurite-positive cells, as well as the average length of neurites, was significantly greater than the normal blank serum-treated PC12 cells （P 〈 0.05 or P 〈 0.01）. Compared with the blank control group, MAP2 expression in the Aβ1-40-treated PC12 cells was significantly inhibited, and the cell proliferation rate was significantly decreased （P 〈 0.01）. Following incubations with natural-cerebrolysin-containing serum, MAP2 expression and cell proliferation rate in the PC12 cells were significantly increased in a dose-dependent manner, compared with treatments with blank control serum （P 〈 0.05 or P 〈 0.01 ）.
CONCLUSION： Natural-cerebrolysin exhibited antagonistic effects on neurotoxicity in Aβ1-40 induced Alzheimer＇s disease in vitro models. These effects were likely related to cell proliferation and the upregulation of intracellular MAP2 expression.