血管性痴呆大鼠海马神经型胆碱能受体的变化

目的 探讨血管性痴呆(VD)大鼠海马神经型胆碱能受体(nAChR)的变化.方法 改良四血管法建立VD大鼠模型;术后1个月,采用Morris水迷宫试验检测VD大鼠的学习和记忆功能;应用改良Ellman法测定大鼠血浆及海马乙酰胆碱酯酶(AChE)活性;Western Blot法及RT-PCR法分别检测大鼠海马nAChR亚单位α3、α4、α7蛋白及mRNA的表达水平,并与假手术组比较.结果 与假手术组相比,VD组水迷宫试验逃避潜伏期明显延长,第1次穿越平台时间延长,穿越平台次数减少(均P<0.01);血浆AChE活性降低(P<0.01),海马AChE活性升高(P<0.05);海马nAChR α3、α4、α7蛋白及nAChR α3、α7 mRNA表达水平明显下降(P<0.05～0.01),nAChR α4 mRNA表达水平明显升高(P<0.01).结论 海马神经元nAChR表达的降低可能是VD大鼠认知功能受损害的基础.     

bFGF对血管性痴呆大鼠海马乙酰胆碱含量及胆碱酯酶活性的影响

目的皮下注射碱性成纤维细胞生长因子于血管性痴呆大鼠,研究用药前后大鼠乙酰胆碱含量及胆碱酯酶活性的变化。方法制作VD大鼠模型,随机取用VD大鼠模型12只,分治疗组6只,痴呆组6只。另外,取假手术组6只。皮下注射碱性成纤维细胞生长因子于治疗组中的血管性痴呆大鼠。治疗5周后,以Morris水迷宫定位航行试验和空间探索试验来检测大鼠的学习记忆能力,观察乙酰胆碱含量及胆碱酯酶活性的变化。结果治疗组大鼠学习记忆能力较痴呆组明显提高,治疗组乙酰胆碱含量较痴呆组明显提高,胆碱酯酶活性明显降低。结论皮下注射碱性成纤维细胞生长因子能明显提高血管性痴呆大鼠乙酰胆碱含量,降低胆碱酯酶活性。     

血管性痴呆小鼠海马组织学改变及乙酰胆碱酯酶活性变化特征

目的:探讨血管性痴呆(VD)小鼠海马组织病理学改变及乙酰胆碱酯酶病理(AchE)活性的变化特征.方法:将50只小鼠随机分为假手术组和模型组。模型组采用双侧颈总动脉反复缺血再灌注法制备VD模型,术后第29天和第30天测试学习记忆成绩,术后第30天检测海马CA1区组织学变化及AchE含量。结果:VD模型组小鼠学习记忆成绩较假手术组明显下降;海马CA1区锥体细胞数目减少,细胞核体积变小;且模型组小鼠海马AchE活性明显低于假手术组(P<0.01)。结论:小鼠海马组织内的AchE活性下降参与了VD的形成,进一步导致VD小鼠的学习和记忆障碍。     

双氢麦角碱对血管性痴呆小鼠海马乙酰胆碱酯酶活性变化的影响

目的探讨双氢麦角碱对血管性痴呆（VD）小鼠海马组织乙酰胆碱酯酶（AchE）活性变化的影响。方法将75只小鼠随机分为假手术纽、模型组和药物纽。药物组和模型组采用双侧颈总动脉反复缺血再灌注法制备VD模型，术后第29天和第30天测试学习记忆成绩，术后第30天检测海马AchE含量，并研究双氢麦角碱对二者的影响。结果（1）模型组小鼠学习记忆成绩较假手术组明显下降（P〈0．01），治疗组小鼠学习记忆成绩明显优于模型组小鼠（P〈0．01）；（2）模型组小鼠海马AchE活性较假手术组明显降低（P〈0．01），治疗组小鼠海马AchE活性显著高于模型组小鼠（P〈0．05）。结论双氢麦角碱能改善VD小鼠的学习记忆功能，提高海马组织内的AchE活性。     

不同形式Aβ对老年痴呆细胞模型中炎性因子和神经型尼古丁乙酰胆碱受体表达的影响

目的 研究Aβ寡聚体(Amyloid-beta oligomers,Aβoligomers,AβOs)在阿尔茨海默氏病(Alzheimer Disease,AD)患者中的表达情况,用不同聚集形式的Aβ处理拟老年痴呆细胞模型中肿瘤坏死因子-α(Tumor necrosjs factor-α,TNF-α)、炎性趋化因子单核细胞趋化蛋白1(Monocyte chemoattractant protein 1,MCP-1/CCL-2),巨噬细胞炎性蛋白-1α(Macrophage inflammatory protein-1α,MIP-1α/CCL-3)及神经型尼古丁乙酰胆碱受体(Neuronal nicotinic acetylcholine receptors,nAChRs)的表达.探讨炎性因子及nAChRs与Aβ寡聚体在阿尔茨海默氏病发病机制中的作用.方法 应用免疫组织化学方法检测AD患者(海马结构、颞叶及额叶皮质)Aβ寡聚体的表达.Elisa检测拟老年痴呆细胞模型中各组细胞TNF-α、MCP-1、MIP-lα的表达.Western blotting检测拟老年痴呆细胞模型中各组细胞α3、α7nAChRs的表达.结果 AβOs主要在神经细胞内表达,齿状回颗粒细胞、海马CA1-CA4锥体细胞及内嗅区皮质各层神经元胞体及突起内均见棕黄色粒状阳性表达,此外,小血管壁也见AβOs阳性表达.与老龄对照者相比,AD患者海马各区锥体细胞及内嗅区皮质各层神经元AβOs表达明显增强,半定量分析显示平均灰度值显著降低,差异有统计学意义(P＜0.05,P＜0.01).采用1mol/L浓度的Aβ1-42单体、纤丝体及寡聚体处理SH-SY5Y细胞48h后与对照组相比,Aβ寡聚体处理组α3、α7nAChRs蛋白表达水平明显降低,炎性因子明显升高(P＜0.05).结论 Aβ寡聚体能升高TNF-α、MCP-I、MIP-Iα,加速Aβ沉积,形成恶性循环的慢性炎症过程,降低神经型尼古丁乙酰胆碱受体α3、α7nAChRs的表达,说明AD发病机制中可溶性、呈寡聚状态的AβOs可能是引起AD神经元功能失调的主要神经毒性形式.     

小血管病性血管性认知障碍非痴呆型患者神经心理学特征的研究

目的通过系列神经心理学测试对小血管病性血管性认知障碍非痴呆型(VCIND-SVD)患者的神经心理学特征进行分析,寻找适用于VCIND-SVD患者的敏感且简捷的神经心理评估工具。方法VCIND-SVD患者33例,正常对照组40例,进行MMSE及多个包括5个认知域在内的神经心理学测试,确定VCIND-SVD患者受损的认知域,筛选出识别能力较好的单项测试,检测其敏感度和特异度,以便临床使用。结果VCIND-SVD患者为多个认知域损害,包括记忆力、注意力、语言功能、视空间结构技能及执行功能均有损害;即刻逻辑记忆测试、积木测试、伦敦塔完成时间及计划时间等检测项目能敏感反映这些损害。结论各单项测试的综合对VCIND-SVD具有较强的识别能力,有重要的应用价值。     

血管性痴呆患者血清CGRP、NPY水平的变化及意义

目的探讨血管性痴呆(VD)患者血清中降钙素基因相关肽(CGRP)及神经肽Y(NPY)水平的变化及其意义。方法测定VD组、脑梗死非痴呆组(CI组)、健康对照组(NC组)血清CGRP及神经肽NPY水平变化,分析与蒙特利尔认知评估量表(MoCA)评分的关系。结果 VD组MoCA评分、CGRP水平低于NC组和CI组,NPY水平高于NC组和CI组,差异均有统计学意义(P<0.05)。VD组的MoCA评分与血清CGRP水平呈正相关(r=0.439,P<0.01),与血清NPY水平呈负相关(r=-0.278,P<0.05)。结论脑的长期慢性低灌注是VD发生发展的主要危险因素。脑血管舒缩功能平衡失调既可能是脑缺血缺氧的结果,又可能是进一步导致脑细胞损伤的重要原因。     

α3神经型尼古丁受体基因上调对SH-SY5Y细胞突触素水平的影响

目的构建使α3nAChR基因上调的重组质粒α3nAChR-pcDNA3.1并转染至神经母细胞瘤细胞(SH-SY5Y),研究α3nAChR基因上调对细胞突触素(SYP)水平的影响。方法设计α3nAChR上下游引物,通过逆转录PCR的方法获取人α3nAChR特异核苷酸序列,并将其克隆到质粒载体pcDNA3.1上,构建重组质粒α3nAChR-pcDNA3.1;瞬时转染至SH-SY5Y细胞后,用Real-time法和蛋白免疫印迹法分别α3nAChR及蛋白水平,并检测上调细胞中SYPmRNA和蛋白水平的变化。结果成功构建了使α3nAChR基因上调的重组质粒α3nAChRpcDNA3.1;将α3nAChR-pcDNA3.1质粒转染到SH-SY5Y细胞后,与空载质粒组及正常对照组相比,α3nAChRmRNA及蛋白表达水平分别增加了422%和106%(P0.05);SYPmRNA及蛋白表达水平分别增加了115%和43%(P0.05)。结论α3nAChR表达的上调可使细胞SYP的表达增加,说明了α3nAChR与SYP密切相关,在AD的发生中可能起着重要作用。     

血管性痴呆小鼠海马胆碱乙酰转移酶mRNA变化特征及喜得镇的影响

目的:观测喜得镇对血管性痴呆小鼠海马神经元胆碱乙酰转移酶mRNA变化的影响,以探讨胆碱乙酰转移酶mRNA变化在血管性痴呆发病中的作用及喜得镇对此变化的机制。方法:双侧颈总动脉线结.反复缺血-再灌注法制备模型,药物组用喜得镇溶液灌胃,利用跳台试验和水迷宫试验观测其行为学改变,采用原位杂交技术观测小鼠海马神经元胆碱乙酰转移酶mRNA的表达变化。结果:喜得镇组小鼠学习、记忆成绩优于模型组(P<0.01),其海马胆碱乙酰转移酶mRNA表达也明显增高(P<0.01)。结论:喜得镇改善血管性痴呆小鼠学习、记忆成绩与其恢复海马低水平的胆碱乙酰转移酶mRNA有关。     

血管性痴呆小鼠海马胆碱乙酰转移酶mRNA表达特征及石杉碱甲的影响

目的观测石杉碱甲对血管性痴呆小鼠海马神经元胆碱乙酰转移酶(ChAT)原位杂交的影响,进一步研究其在血管性痴呆发病中的作用及石杉碱甲对其影响的机制。方法双侧颈总动脉线结,反复缺血-再灌注法制备模型,药物组用石杉碱甲溶液灌胃,跳台试验和水迷宫试验观测其行为学改变,采用原位杂交技术观测小鼠海马神经元ChAT mRNA的表达变化。结果石杉碱甲组小鼠学习、记忆成绩优于模型组(P<0.01),其海马ChATmRNA表达也明显增高(P<0.01)。结论石杉碱甲改善血管性痴呆小鼠学习、记忆成绩与其恢复海马低水平的ChAT mRNA有关。     

The effect of cholinesterase inhibitors on the regional blood flow in patients with Alzheimer's disease and vascular dementia

The effects of therapy with cholinesterase inhibitors (ChE-I) on regional cerebral blood flow (rCBF) disturbances were investigated by means of single photon emission computed tomography (SPECT). The changes in rCBF were compared with the results of the medical examination and neuropsychological tests. The sample consisted of 41 patients with the Alzheimer's dementia (AD) and vascular dementia (VaD). The effect of ChE-I (rivastigmine) treatment was studied on 33 patients, while the nontreated control group consisted of 8 patients. In the treated patients, an increase in the rCBF was observed, while the scores of the neuropsychological tests decreased slightly. In the VaD group, the increase in rCBF was more significant in the frontal regions, whereas in the group with AD in the temporal regions, respectively. In the nontreated patients, a decrease of both rCBF and scores of neuropsychological tests were observed. The scores of the neuropsychological tests correlated with the results of rCBF. Increased levels of acetylcholine in the brain after ChE-I treatment may support the cholinergic regulation of rCBF, and in result increase it. Such effects seem to be more pronounced in the more affected brain regions.     

Blood cells cholinesterase activity in early stage Alzheimer's disease and vascular dementia

Blood acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) activities have been studied as markers for Alzheimer's disease (AD), but their usefulness as a disease marker is controversial. To determine cholinesterase (ChE) activity during AD progression and whether ChE changes associate to other dementias, ChE activity was measured in lymphocytes, erythrocytes and platelets. Subjects underwent extensive medical and neuropsychological examination. Both early-AD and AD patients had lower AChE activity in lymphocytes compared to control subjects (p < 0.0001). In contrast, erythrocyte AChE activity was higher in patients with vascular dementia (p = 0.004). Low ChE activity in lymphocytes was the best discriminator for AD. Because it was already low at very early stages of AD, ChE could be helpful as an early biomarker of differential diagnosis for the follow-up of patients during their early stages of cognitive impairment before a clinical dementia is established.     

Estrogen receptor gene polymorphisms in patients with Alzheimer's disease, vascular dementia and alcohol-associated dementia

The association between the estrogen receptor (ER-alpha) gene and dementia was examined in 223 patients with Alzheimer's disease (AD), 66 with vascular dementia (VD), 17 with alcohol-associated dementia (ALD) and 134 healthy elderly control subjects. The PvuII and XbaI restriction fragment length polymorphisms of the ER-alpha gene were represented as Pp (PvuII) and Xx (XbaI), with capital letters signifying the absence of restriction sites and small letters the presence of restriction sites. We found that the frequency of the ER-alpha gene P allele and X allele in the late-onset AD (LOAD) group (P allele was 0.51, X allele was 0.30) was significantly higher than that in controls (P 0.38, p < 0.01; X 0.20, p < 0.01), and that the frequency of the ER-alpha gene P allele and PP genotype was significantly different between apolipoprotein E epsilon4 carriers and noncarriers in LOAD. These findings suggest that the genotype of the ER-alpha gene may be specific in LOAD, and that the ER-alpha gene was an additional risk for LOAD.     

Reduced cholinesterase activity and somatostatin-like immunoreactivity in the cerebrospinal fluid of patients with dementia of the Alzheimer type

Cholinesterase (ChE) activity and somatostatin-like immunoreactivity (SLI) of the cerebrospinal fluid were determined for 59 patients with dementia of the Alzheimer type (AD/SDAT) and for 19 age-matched control patients with no signs of dementia. Both ChE activities and SLI concentrations of cerebrospinal fluid were reduced significantly in dementia patients compared to the controls. In the AD/SDAT patients cholinesterase and somatostatin-like immunoreactivity levels seemed to be correlated with the severity of dementia. These findings agree with observations of reduced cortical acetylcholinesterase activities and somatostatin values in dementia of the Alzheimer type.     

Serum paraoxonase activity changes in patients with Alzheimer's disease and vascular dementia

The prevalence of Alzheimer's disease (AD) and vascular dementia (VAD) increases with aging of the population. The role of lipoproteins in the pathogenesis of AD is unclear: apoE₂ offers protection and apoE₃ is neutral, while apoE₄ promotes the development of the disease. Recently, several studies have confirmed the role of oxidative stress in the pathogenesis of AD and VAD. HDL-associated paraoxonase is one of the antioxidative enzymes that may reduce LDL oxidation. In our study, we investigated the lipid parameters of the sera and the serum paraoxonase activity in patients with AD and VAD. Lipid parameters were determined by an autoanalyzer in 30 AD patients, 40 VAD patients and 40 healthy, age-matched control (C) subjects. Paraoxonase activity was measured spectrophotometrically using paraoxon as the substrate. The phenotypic distribution of paraoxonase was determined by the dual substrate method, using paraoxon and phenylacetate as substrates. In our results, we found that most of the patients with AD had the apoE4 isoform, consistent with other studies. In the VAD and AD patients we found significantly higher total-cholesterol compared to the control group (C: 4.71 ± 0.89, VAD: 6.3 ± 0.8, AD: 6.52 ± 0.7 mmol/l; p < 0.01) and LDL-cholesterol levels (C: 2.6 ± 0.6, VAD: 3.96 ± 0.8, AD: 3.84 ± 0.6 mmol/l; p < 0.001). The HDL-associated antioxidant, paraoxonase activity did not differ significantly in the patient groups, but compared to the healthy control subjects, paraoxonase activity was significantly lower in both of the patient groups (C: 188 ± 55 U/l; AD: 131 ± 37, VAD: 151 ± 50 l; p < 0.05). Our results suggest that the defect in HDL-associated antioxidant capacity plays a role in the pathogenesis of Alzheimer's disease and vascular dementia. Received: 30 November 2001 / Accepted: 24 January 2002     

Cerebral blood flow and oxygen metabolism in patients with vascular dementia of the Binswanger type

We performed clinical and neuroradiologic studies, including positron emission tomography, in five patients with vascular dementia of the Binswanger type. The clinical features of these cases consisted of slowly progressive dementia, together with vascular risk factors such as hypertension and often a history of minor stroke, and characteristic white matter lesions on brain computed tomograms or magnetic resonance images. Digital subtraction angiography of the cervical and intracranial arteries demonstrated no occlusive lesion in any patient. Both cerebral blood flow and the cerebral metabolic rate for oxygen were markedly reduced in the white matter (54-77% of control values), and both were decreased in the parietal (73% of control), frontal (74-80%), and temporal (74-83%) cortices, where no abnormalities were detected by brain computed tomography or magnetic resonance imaging. We conclude that vascular dementia of the Binswanger type may be caused by disconnection between the cerebral cortex and subcortical structures due to ischemic damage in the white matter.     

Serum and CSF cholinesterase activity in various kinds of dementia

Summary The activity of acetyl- and butyrylcholinesterase was determined in serum and CSF of controls and patients suffering from different types of dementia. A statistically significant decrease in the activities of both esterases was observed in CSF of demented patients, however, primary degenerative and vascular dementia did not differ in their CSF cholinesterase levels. Compared to age-matched controls the serum butyrylcholinesterase activity was also significantly lowered in the overall dementia group. No typical serum and CSF cholinesterase isoenzyme pattern was found for dementia or any of its subgroups. It is concluded that the cholinesterase levels reflect metabolic alterations associated with dementia as a collective group but cannot be used for differential diagnosis of subgroups.     

Apolipoprotein E in patients with dementia of the Alzheimer type and vascular dementia

The phenotypes of apolioprotein E (ApoE) in the plasma of patients with dementia of the Alzheimer type (DAT) and vascular dementia (VD) were determined by the isoelectric focusing method. The ApoE mRNA level in the skin fibroblasts was also determined by the Northern blot analysis. As compared with the control subjects, the frequency of the ApoE ε4 allele was significantly higher in the DAT group as well as the VD group, but was not significantly different in the cerebrovascular disease without dementia (CVD) group. The skin fibroblast ApoE mRNA level in the DAT group and the VD group was significantly lower than that in the control group. These findings suggest that the phenotype of ApoE is associated with DAT and VD, and that the lower level of ApoE mRNA may play an important role in the development of DAT as well as VD.     

Serotonin 5-HT2A receptor binding in platelets from patients with Alzheimer's disease or vascular dementia

It is well known that abnormalities in the brain serotonin system exist in patients with dementia. The present study was performed in order to investigate whether a peripheral serotonin system marker, the platelet 5-HT2A receptor, is affected in dementia. Thirty-eight patients with Alzheimer's disease (AD), 13 patients with vascular dementia, and 40 healthy controls were included in the study. There were no significant differences in receptor density for 5-HT2A receptor binding between the groups. Affinity of the radioligand to the receptor was significantly lower in AD than in vascular dementia and in the controls (p = .006 and p = .003, respectively), whereas there was no significant difference between the vascular dementia group and the control group. In 12 patients, treatment with citalopram was started due to depression or agitation. This treatment significantly reduced the Behavioral Pathology in Alzheimer's Disease Rating Scale scores (p = .001), but did not affect the platelet 5-HT2A receptor status. There was no correlation between 5-HT2A receptor status before treatment and the therapeutic effect of citalopram. The study indicates that platelet 5-HT2A receptor status is of limited value as a peripheral marker in dementia.