胰高血糖素样肽1及其类似物治疗阿尔茨海默病作用机制研究进展

研究发现阿尔茨海默病(AD)的许多病理特征和认知功能下降可能与脑内胰岛素抵抗有关。对AD动物模型和轻度认知功能障碍患者的脑组织进行研究,结果表明应用胰高血糖素样肽1(GLP-1)类似物如利拉鲁肽、艾塞那肽治疗后,脑内胰岛素抵抗和许多病理特征减少或是逆转。这一研究结果为GLP-1类似物对AD的潜在治疗研究提供理论基础。对GLP-1及其类似物在AD中的潜在治疗作用做一综述。     

胰高血糖素样多肽1—治疗糖尿病的多肽,是治疗阿尔茨海默病的新希望?(英文)

胰高血糖素样多肽1(Glucagon-like peptide,GLP)已被证明是有前景的II型糖尿病(Type 2 diabetes mellitus,T2DM)治疗剂。阿尔茨海默病(Alzheimer’s disease,AD)和T2DM具有在淀粉样蛋白β(Amyloid β,A β),tau 蛋白磷酸化和葡萄糖合成酶3等方面的共同的病理生理特征。GLP-1具有神经营养特性,并能降低脑淀粉样蛋白水平。过去几十年对AD的广泛研究使我们认识到对其治疗应针对Aβ和tau蛋白。总结这些之后发现,GLP-1可能有希望用于治疗AD。本文综述了GLP-1的生物化学和生理学特征,T2DM和AD的共同的病理生理特征,以及GLP-1在治疗T2MD和改善AD某些病理变化方面的新进展。     

胰高血糖素样多肽1-治疗糖尿病的多肽,是治疗阿尔茨海默病的新希望?

胰高血糖素样多肽l（Glucagon-like peptide,GLP）已被证明是有前景的Ⅱ型糖尿病（Type 2 diabetes mellitus,T2DM）治疗剂。阿尔茨海默病（Alzheimer’s disease,AD）和T2DM具有在淀粉样蛋白β（Amyloid β,Aβ）,tau蛋白磷酸化和葡萄糖合成酶3等方面的共同的病理生理特征。GLP-1具有神经营养特性,并能降低脑淀粉样蛋白水平。过去几十年对AD的广泛研究使我们认识到对其治疗应针对Aβ和tau蛋白。总结这些之后发现,GLP-1可能有希望用于治疗AD。本文综述了GLP-1的生物化学和生理学特征,T2DM和AD的共同的病理生理特征,以及GLP-1在治疗T2MD和改善AD某些病理变化方面的新进展。     

表达胰高血糖素样肽1重组腺伴随病毒载体的构建

背景：胰高血糖素样肽1(glucagon-like peptide-1, GLP-1)在人体内半衰期过短限制了其应用。 目的：构建可表达GLP-1的重组腺伴随病毒。 方法：将NT4-GLP-1融合基因插入腺伴随病毒包装质粒pSSHG-CMV中,构建pSSHG/NT4-GLP-1重组腺伴随病毒包装质粒。采用磷酸钙共沉淀法将辅助质粒pAAV/Ad、腺病毒质粒pFG140及pSSHG/NT4-GLP-1转染至293细胞系,用其感染Hela细胞。 结果与结论：重组质粒pSSHG/NT4-GLP-1经限制性内切酶EcoRⅠ酶切鉴定可见342 bp的目的片段,说明NT4-GLP-1融合基因已经成功重组于腺伴随病毒包装质粒pSSHG-CMV内。免疫细胞化学结果显示,转染pSSHG/NT4-GLP-1重组腺伴随病毒包装质粒的Hela细胞内有大量棕黄色颗粒,阳性率达到70%以上,说明NT4-GLP-1重组腺伴随病毒在细胞中可以表达GLP-1。     

胰高血糖素样肽-1对神经系统的保护作用

<正>对于2型糖尿病患者,胰高血糖素样肽-1(glucagon like peptide-1,GLP-1)不仅能够调节血糖,还可以减少胰腺细胞的凋亡,近年有研究表明它还具有神经营养和神经保护作用。(一、GLP-1作用机制1902年,Bayliss和Starling推测有一种"促胰液素",在食物摄入后刺激胰腺分泌一些因子。因其可刺激胰岛素分泌,故而将这种自上段肠道分泌的激素命名为"肠促胰素"。口服葡萄糖较静脉注射葡萄糖促使更多的胰岛素分泌证实了肠促胰素的存在。葡萄糖依赖性促胰岛素激素(glucose-dependent insulino-     

胰高血糖素样肽1受体激动剂在神经保护方面的研究进展

近年来的研究发现,与糖尿病并发的多种神经系统疾病,可随着治疗糖尿病的胰高血糖素样肽1受体激动剂(GLP-1RA)的使用而得到改善,但其具体机制尚不完全清楚。天然的GLP-1是进食诱导刺激回肠和结肠的L细胞分泌的肠肽类激素,其可促进胰岛素的合成和分泌。为克服GLP-1半衰期短而开发的多种长效GLP-1RA已经在临床上广泛应用,如艾塞那肽、利拉鲁肽、阿必鲁肽、度拉糖肽等,这些药物表现出在控制血糖水平和体重上的优势。由于GLP-1受体广泛分布于胰腺、肺、脑、心脏、肾和胃肠等组织细胞膜上,因此GLP-1RA的作用不仅仅在治疗糖尿病方面。已有的报道表明,GLP-1RA还具有显著的神经、心血管、肾脏保护,以及抗呼吸道炎症和减脂等多种作用。GLP-1受体在脑中亦有广泛分布,且GLP-1RA可有效通过脑血管屏障。GLP-1RA与相应受体结合,可激活PKA、PI3K/AKT、ERK、MEK等多个激酶信号通路,调节神经递质传递,这可能是GLP-1RA实现抗炎、减少氧化应激、抑制凋亡、减少DNA损伤、神经细胞修复,最终达到神经保护的途径。该文结合基础及临床研究,对GLP-1RA在缺血性脑卒中、认知功能障碍、...     

拟阿尔茨海默病模型大鼠海马CA1区HSP27及IL-1表达

目的 探讨Aβ(β-淀粉样肽)诱AD大鼠模型中海马HSP27和IL-1的表达, 研究信号转导及炎性机制在AD中的作用.方法 采用立体定向下双侧海马注射Aβ1-42建立AD动物模型,通过免疫组化染色及Western blot等方法, 观测大鼠学习记忆能力、海马组织结构的病理改变及HSP27和IL-1 的表达情况.结果 HE染色显示,模型组大鼠海马神经元变性、缺失,胶质细胞浸润;免疫组化结果显示模型组大鼠海马CA1区HSP27和IL-1 免疫阳性细胞表达多见(P＜0.05);Western blot显示模型组海马组织HSP条带增宽表达强度高于对照组(P＜0.05).结论 HSP27在AD的炎症反应机制中可能具有重要作用.     

基于p38丝裂原活化蛋白激酶通路的胰高血糖素样肽-1对大鼠脑缺血再灌注损伤的影响及机制

目的基于p38丝裂原活化蛋白激酶(p38MAPK)通路探讨胰高血糖素样肽-1(GLP-1)对大鼠脑缺血再灌注(I/R)损伤的影响及机制。方法将雄性SD大鼠分为假手术组、模型组、GLP-1组和p38MAPK抑制剂组,每组12只。模型组、GLP-1组和p38MAPK抑制剂组通过大脑中动脉栓塞及再灌注建立脑I/R损伤模型,GLP-1组给予利拉鲁肽(70μg/kg)、p38MAPK抑制剂组给予p38MAPK抑制剂SB202190(10μmol/L、5μl)干预。比较四组大鼠的脑梗死体积、水迷宫行为参数及梗死脑组织细胞凋亡率、氧化应激指标、炎症细胞因子、p38MAPK通路分子的差异。结果与模型组比较,GLP-1组和p38MAPK抑制剂组大鼠的脑梗死体积明显降低,逃避潜伏期明显缩短、穿越平台次数明显增多,梗死脑组织中的细胞凋亡率及丙二醛(MDA)、超氧化物歧化酶(SOD)、TNF-α、IL-1β、IL-6、p-p38水平显著减少,SOD、谷胱甘肽过氧化物酶(GPx)水平明显增加(均P<0.05),p-ERK1/2、p-JNK的表达水平无明显变化。与假手术组比较,模型组大鼠的逃避潜伏期明显延长、穿越平台次数明显减少,梗死脑组织的细胞凋亡率及MDA、ROS、TNF-α、IL-1β、IL-6、p-p38水平明显增高,SOD、GPx水平明显减少(均P<0.05),p-ERK1/2、p-JNK的表达水平无明显变化。结论GLP-1能够通过抑制p38介导的氧化应激及炎症反应减轻大鼠脑I/R损伤。     

利西拉肽对阿尔茨海默病保护作用机制的研究进展

近年来,越来越多的临床和实验数据表明2型糖尿病与阿尔茨海默病之间关系密切。2型糖尿病和阿尔茨海默病具有共同的病理生理特征:β淀粉样蛋白沉积、tau蛋白过磷酸化和葡萄糖合成酶3活性增加。研究发现2型糖尿病患者患阿尔茨海默病的风险与正常人比较有增加的趋势。对阿尔茨海默病动物模型脑组织进行研究,结果表明应用胰高血糖素样肽1类似物治疗后,脑内胰岛素抵抗得到改善,四羟壬烯酸、丙二醛等氧化应激指标显著减少,而其他病理特征有逆转的趋势,特别是新型的胰高血糖素样肽1受体激动剂利西拉肽作用更显著,且不良反应事件更少。最新文献证实利西拉肽具有神经保护作用,可用于阿尔茨海默病的治疗。文中就利西拉肽在阿尔茨海默病中的作用做一综述。     

阿尔茨海默病的线粒体功能紊乱机制

线粒体对于神经元的生存发挥关键作用,氧化应激引起细胞凋亡是AD早期的主要特征.线粒体形态结构发生改变和线粒体DNA突变都可以造成线粒体功能紊乱,表现为电子传递链的损伤如细胞色素氧化酶活性降低,线粒体动力学异常如线粒体自噬增加、分裂融合失衡、生物合成障碍、转运功能下降等,淀粉样蛋白生成进一步增加,最终导致不可逆的神经元损伤,散发性AD发生.针对线粒体损伤的治疗措施,为AD的治疗带来新的选择.     

脑蛋白水解物注射液改善阿尔茨海默病认知功能的机理探究

目的通过研究脑蛋白水解物注射液(CL)对体外培养神经祖细胞(NPCs)增殖和分化的影响,探讨其改善阿尔茨海默病认知功能的机理。方法从成年大鼠脑不同区域原代及传代培养神经祖细胞,以乳酸脱氢酶(LDH)分析法测定细胞活性,以免疫荧光染色法鉴定细胞性质,以蛋白印迹转移(Western blot)法检测蛋白质表达变化。结果CL处置明显增加神经祖细胞数及MAP2a/b、SynapsinⅠ表达水平。结论CL促进神经祖细胞增殖和向神经元分化,可能是其改善阿尔茨海默病认知功能的机理之一。     

Characterizing regional correlation, laterality and symmetry of amyloid deposition in mild cognitive impairment and Alzheimer's disease with Pittsburgh Compound B

We evaluated the region-to-region correlation, laterality and asymmetry of amyloid deposition in subjects with mild cognitive impairment (MCI) or Alzheimer's disease (AD) using the amyloid tracer, Pittsburgh Compound B (PiB). Seventeen subjects, including 7 with MCI (MMSE 26.7+/-2.4) and 10 with AD (MMSE of 24.8+/-2.7) underwent PiB imaging. Measures of laterality (i.e., group-wise predilection for right or left) and asymmetry (i.e., group-wise predilection for unequal PiB retention between the two hemispheres) were calculated for 17 Regions of Interest (ROIs). Regional correlations were calculated along with within-group and between-groups statistical analyses of laterality and asymmetry metrics. The median correlation between PiB retention across all pairs of ROIs was 0.65, with highest correlations found in areas of highest PiB retention (r=0.74). Overall, PiB retention was symmetric bilaterally, but there was PiB laterality in MCI in dorsal frontal cortex [(t(6)=3.05, p=0.02, L>R] and sensory-motor area [t(6)=3.10, p=0.02, L>R] and in AD in the occipital pole (t(9)=-2.63, p=0.03, R>L). The most significant asymmetries in PiB retention were found in sub-cortical white matter (t(6)=3.99, p=0.01) and middle precuneus [(t(6)=3.57, p=0.01] in MCI, and in lateral temporal cortex (t(9)=3.02, p=0.01) and anterior ventral striatum [t(9)=2.37, p=0.04] in AD. No group differences (AD versus MCI) were detected in laterality [F (1, 15)=0.15, p=0.7] or asymmetry [F (1, 15)=0.7, p=0.42].     

(−)Nicotine inhibits the activations of phospholipases A2 and D by amyloid β peptide

It has been established that amyloid beta peptide (AβP) activates phospholipase A2, phospholipase C and phospholipase D of LA-N-2 cells and other cell types. Nicotine in addition to being a cholinergic agonist, may be neuroprotective. We have investigated the ability of (−)nicotine to blunt the phospholipase activations by AβP in LA-N-2 cells. (−)Nicotine inhibits the AβP activation of phospholipase A2, with an IC₅₀ of 76 μM and of phospholipase D with an IC₅₀ of 252 μM. (−)Nicotine did not blunt the AβP activation of phospholipase C. These inhibitions of AβP activations were not observed with (+)nicotine or cotinine. The (−)nicotine inhibition of AβP activation of these two phospholipases was unaffected by hexamethonium and D-tubocurarine. There was no inhibition of the phospholipase A2 activity present in homogenates of LA-N-2 cells. Exposure of LA-N-2 cells to (−)nicotine for 2 h resulted in the blockade of phospholipase A2 activation by kainate and AβP but did not affect the ability of quisqualate and AβP to activate phospholipase D. These data suggest that if the nicotine inhibition of AβP activations is receptor occupancy mediated then it is by an atypical receptor type.     

Lysosome-associated membrane protein 1 (LAMP-1) in Alzheimer's disease

Lysosome-associated membrane protein 1 (LAMP-1) is a glycoprotein highly expressed in lysosomal membranes. The present study was initiated to test LAMP-1 mRNA and protein levels in post mortem frontal cortex (area 8) of Alzheimer's disease (AD) stages I-IIA/B and stages V-VIC of Braak and Braak, compared with age-matched controls. TaqMan PCR assays and Western blots demonstrated upregulation of LAMP-1 mRNA and protein in the cerebral cortex in ADVC. In addition, immunohistochemical studies have shown increased LAMP-1 immunoreactivity in neurones, and in glial cells surrounding senile plaques, in AD cases. Interestingly, LAMP-1 immunoreactivity has little correlation with phosphorylated tau deposition and neurofibrillary tangles (NFTs), as neurones with NFTs were rarely LAMP-1 immunoreactive. In contrast, LAMP-1 expression was enhanced in neurones with granulovacuolar degeneration. Finally, LAMP-1 occurred in microglia and multinucleated giant cells in one AD case in whom amyloid burden was cleared following betaA-peptide immunization. These findings support the participation of lysosomes in betaA-amyloid and, probably, in hyperphosphorylated tau turnover in AD.     

曲克芦丁对AD模型大鼠认知功能、脑内胆碱能系统及脑细胞凋亡的影响

目的 研究曲克芦丁对β淀粉样蛋白(Aβ25-35)诱导大鼠AD模型的影响,为AD药物的研发提供实验依据.方法 50只SD大鼠采用随机数字表法分为5组,每组10只,分别为对照组、模型组、曲克芦丁低、中、高剂量治疗组.对照组和模型组给予10 mg/kg体质量5％羧甲基纤维素钠灌胃,曲克芦丁治疗组按不同剂量灌胃给药,低剂量治疗组为10 mg/kg,中剂量组为20mg/kg,高剂量组为50 mg/kg.各组大鼠灌胃14d后,模型组和各剂最曲克芦丁治疗组大鼠双侧海马区注射Aβ25-35 1μL,对照组不做处理.敞箱实验检测各组大鼠运动功能改变情况,Y型迷宫检测各组大鼠认知情况改变情况.比色法测定各组大鼠海马ChAT、AchE的活性,Western blotting检测Bcl和Bax表达水平.结果 敞箱实验中,中高剂量治疗组大鼠、垂直水平运动得分均较模型组大鼠明显提高,差异有统计学意义(P＜0.05).Y型迷宫实验中,中高剂量治疗组大鼠正确反应次数较模型组大鼠明显提高,差异有统计学意义(P＜0.05).与模型组相比,高剂量治疗组ChAT活性明显升高,差异有统计学意义(P＜0.05).各组大鼠AchE活性差异无统计学意义(P＞0.05).与模型组比较,中高剂量治疗组Bcl表达明显增加,Bax表达明显降低,差异均有统计学意义(P＜0.05).结论 曲克芦丁对Aβ25-35聚集引起的神经毒性具有保护作用,其机制与ChAT活性上调有关.     

The prevalence of amyloid (A4) protein deposits within the cerebral and cerebellar cortex in Down's syndrome and Alzheimer's disease

Summary The extent of amyloid deposition within the cerebellum and the cerebral cortex was assessed and compared, using anti-amyloid protein (A4) immunostaining and a novel methenamine silver method, in 20 patients aged between 60 and 77 years with Alzheimer's disease (AD), 29 patients aged between 13 and 71 years with Down's syndrome (DS), 26 demented patients with disorders other than AD and DS and in 20 non-demented elderly individuals of age range 60–102 years. In AD, amyloid deposits were noted in the cerebellar cortex in 90% of patients and in the meningeal vessels of the cerebellum in 80% of patients. In DS, amyloid deposits were seen in the cerebellar cortex in 82% of patients over 30 years of age and was universal in patients over 50 years of age. Overall, in DS, amyloid deposits were present in the meningeal vessels of the cerebellum in 79% of patients, but were present in 94% of those patients over 50 years of age. The sites of amyloid deposition in the cerebellar cortex were (poorly) detected by lectin histochemistry (Concanavalin A binding) in only 40% of patients with AD and 43% of all patients with DS (69% of those over 50 years of age). No amyloid deposits were seen in either the cerebellar cortex or its meningeal vessels in any of the 20 non-demented elderly individuals nor in any of the non-Alzheimer demented patients. The cerebellar amyloid deposits were never associated with a neuritic change [i.e. as characterised by the presence of (taupositive) paired helical filaments (PHF)] and neurofibrillary tangles were seen only in a few cells of the dentate nucleus in a single patient with AD and in three of the elderly DS patients. Amyloid deposits were numerous in the cerebral cortex of all patients with AD and in all, except the 13-year-old patient, with DS. In all the AD patients and in most of the DS patients over 30 years of age, many of the cerebral cortical amyloid deposits were associated with neurites and were strongly recognised by lectin histochemistry. Amyloid deposits were present within the meningeal vessels of the cerebral cortex in 75% patients with AD and 72% of patients, over 30 years of age, with DS (82% of those over 50 years of age). These data indicate that the process of amyloidosis in AD and in elderly DS patients is not restricted to the cerebral cortex and may affect other grey matter regions, particularly the cerebellum. However, it seems to be only in the cerebral cortex that such deposits are widely associated with a reactive neuritic (PHF) change and an accumulation of saccharide. It is probably these latter alterations that mark the process of neuronal (neurofibrillary) degeneration that leads to functional deficits.Supported in part by the North Western Regional Health Authority     

β-淀粉样多肽神经毒性的氧化应激机制和褪黑素神经保护机制研究

目的　观察氧化应激在 β 淀粉样多肽 (Aβ)神经毒性的介导作用和褪黑素 (Mel)神经保护作用的抗氧化机制 ,为老年性痴呆的抗氧化治疗提供依据。方法　新生大鼠原代神经元培养 ,分为实验组 (A1 ,B1 ,C1 ,D1 组 )、治疗组 (A2 ,B2 ,C2 ,D2 组 )和空白对照组。实验组四组分别暴露浓度为 0 5 ,1 0 ,1 0 0 ,2 0 0 μmol/L的Aβ2 5 35,治疗组四组同时暴露 1 0 μmol/LMel。比色法测定丙二醛 (MDA)、还原型谷胱甘肽 (GSH)水平以及过氧化氢酶 (CAT)和谷胱甘肽过氧化物酶 (GSH Px)活力 ,并用MTT法测定培养神经元细胞存活率。统计学方法采用方差分析、t检验和相关分析。结果　细胞存活率与Aβ浓度呈显著性负相关 (r=- 0 834 ,P <0 0 0 1 )。MDA :实验组 (A1 ,B1 ,C1 ,D1 组 ,以下同 )分别为 (2 1±0 5)nmol/L ,(3 1± 0 5)nmol/L ,(4 8± 0 9)nmol/L ,(6 0± 0 6)nmol/L ;治疗组 (A2 ,B2 ,C2 ,D2 组 ,以下同 )分别为 (1 9± 0 3)nmol/L ,(2 3± 0 3)nmol/L ,(2 8± 0 5)nmol/L ,(2 9± 0 4)nmol/L ;对照组为(1 6± 0 2 )nmol/L。GSH :实验组分别为 (8 3± 1 5)g/L ,(5 8± 1 7)g/L ,(4 4± 1 3)g/L ,(3 7± 0 5)g/L ,治疗组分别为 (9 9± 1 6)g/L ,(7 7± 1 7)g/L ,(6 3± 1 2 )g/L ,     

Fructus Broussonetae extract improves cognitive function and endoplasmic reticulum stress in Alzheimer's disease models

This study investigated the effects and possible targets of Fructus Broussonetiae extract,a traditional Chinese medicinal herb,on a model of Alzheimer’s disease induced by beta-amyloid peptide 25-35 and D-galactose.The results revealed that intragastric administration of Fructus Broussonetiae significantly increased the expression of immunoglobulin-binding protein,a key factor in the endoplasmic reticulum stress-signaling pathway in rat hippocampus.In contrast,the treatment significantly decreased expression levels of PKR-like endoplasmic reticulum kinase and C/EBP homologous protein,and substantially improved learning,memory and spatial recognition dysfunction in rats.This evidence indicates that Fructus Broussonetiae extract improves spatial learning and memory abilities in rats by affecting the regulation of hippocampal endoplasmic reticulum stress and activation of the apoptosis pathway.