甲硫哒嗪损伤大鼠学习记忆伴随脑β-淀粉样蛋白的升高

目的观察甲硫哒嗪损伤大鼠学习记忆是否伴随脑内β-淀粉样蛋白(β-amyloid protein,Aβ)水平的升高,探讨甲硫哒嗪引起认知功能受损的机制。方法20只大鼠随机分为对照组和甲硫哒嗪组,连续2wk分别腹腔注射生理盐水和治疗剂量的甲硫哒嗪(10mg·kg-1)。用Morris水迷宫测定大鼠学习记忆能力,用放射免疫分析法测脑组织Aβ含量,用免疫组织化学染色检测β-淀粉样前体蛋白(β-amyloid precursor protein,APP)表达,用RT-PCR方法测定脑中3种APP、α及β-分泌酶mRNA表达。结果甲硫哒嗪组大鼠学习记忆能力下降,脑组织Aβ含量升高(P<0.05),是对照组的1.3倍;脑皮质和海马区APP蛋白表达增高(P<0.05);除APP695、α-分泌酶mRNA表达变化无统计学意义外,脑组织APP751和APP770 mRNA表达升高(P<0.05),相对表达量之和是对照组的2.5倍;β-分泌酶mRNA表达升高(P<0.05),是对照组的2.6倍。结论脑内Aβ水平的增加,可能是甲硫哒嗪引起认知功能损害的原因之一。     

Abnormal APP processing in platelets of patients with Alzheimer’s disease: correlations with membrane fluidity and cognitive decline

Rationale Previous studies have implicated platelet amyloid precursor protein (APP) as a candidate biomarker for Alzheimer’s disease (AD). Platelets contain more than 95% of the circulating APP and enclose the enzymatic machinery for the APP metabolism yielding both soluble APP and amyloid-β peptides. Objectives The objective of this study is to compare the ratio of 130- to 110-kDa fragments of APP in platelets from patients with AD, mild cognitive impairment (MCI), and elderly controls. Materials and methods After subjects were grouped according to diagnosis, APP ratio in platelets was evaluated by means of Western blot analysis. Results The APP ratio was significantly lower in AD patients (1.01 ± 0.21) as compared to controls (1.24 ± 0.21, p = 0.001) and MCI patients (1.18 ± 0.21, p = 0.027), but no significant differences were found between MCI and controls (p = 0.904). In addition, we found positive correlations between the APP ratio and 1,6-diphenyl-1,3,5-hexatriene anisotropy (r = 0.3, p = 0.01), as well as with certain parameters of cognitive decline, namely, the mini-mental state examination score (r = 0.33, p = 0.003), the total Cambridge cognitive test (CAMCOG) score (r = 0.37, p = 0.001), and the score on the memory subscale of the CAMCOG (r = 0.38, p = 0.001). Conclusions The pattern of platelet APP fragments was altered in patients with AD but not in patients with MCI. The alteration of APP fragments was correlated with membrane fluidity and the cognitive decline.     

Platelets as a peripheral district where to study pathogenetic mechanisms of alzheimer disease: the case of amyloid precursor protein

Alzheimer disease is a progressive neurodegenerative disease, characterised by a progressive cognitive and memory decline. From a neuropathological point of view, Alzheimer disease is defined by the presence of characteristic lesions, i.e. mature senile plaques, neurofibrillary tangles (NFTs) and amyloid angiopathy. In particular, accumulation of the amyloid beta-peptide in the brain parenchyma and vasculature is an invariant event in the pathogenesis of both sporadic and familial Alzheimer cases. Amyloid beta-peptide originates from a larger precursor, the amyloid precursor protein (APP) ubiquitously expressed. Among the different peripheral cells expressing APP forms, platelets are particularly interesting since they show concentrations of its isoforms equivalent to those found in brain. Moreover, a number of laboratories independently described alterations in APP metabolism/concentration in platelets of Alzheimer patients when compared to control subjects matched for demographic characteristics. These observations defined the frame of our work aimed to investigate if a correlation between levels of platelet APP forms and Alzheimer disease could be detected. We have reported that patients affected by Alzheimer disease show a differential level of platelet APP forms. This observation has several implications: APP processing abnormalities, believed to be a very early change in Alzheimer disease in neuronal compartment, do occur in extraneuronal tissues, such as platelets, thus, suggesting that Alzheimer disease is a systemic disorder; further, our data strongly indicate that a differential level of platelet APP isoforms can be considered a potential peripheral marker of Alzheimer disease allowing for discrimination between Alzheimer and other types of dementia.     

痴呆病人血小板5-羟色胺浓度初探

目的：探讨痴呆病人5-羟色羟(5-HT,血清素)水平与病情严重程度、精神行为症状之间的关系。方法：将痴呆病人分为阿尔采末病(AD)组、血管性痴呆(VaD)组,对照组为无明显认知损害的精神分裂症老年病人,采集病人外周血4mL测定血小板5-HT浓度。同时采用简易智力状态检查(MMSE)、神经精神科问卷(NPI)和临床大体印象评定量表(CGI)等对病人进行评估。结果：共入组AD病人22例、VaD病人10例及精神分裂症病人10例；3组病人血小板5-HT浓度比较无显著差异(P＞0．05)；血小板5-HT浓度与年龄、性别、用药情况、MMSE和NPI评分不相关(P＞0．05)。结论：总体5-HT水平与认知损害不直接相关,不能作为痴呆病人的精神行为与疾病严重程度的生物学标志。     

Oleanolic acid alleviates oxidative stress in Alzheimer’s disease by regulating stanniocalcin-1 and uncoupling protein-2 signalling

Oxidative stress is thought to play an important role in the occurrence and development of Alzheimer's disease (AD) and antioxidants may delay or even treat AD. Oleanolic acid (OA) exhibits antioxidant properties against many diseases. However, its effects on oxidative stress in AD remain unclear. Here, we explored the role and mechanism of action of OA in N2a/APP695swe cells exposed to oxidative stress. The cells were incubated with different concentrations of OA (0, 5, 8, 10, 15, and 25 μmol/L) for 24 hours. Higher concentrations of OA (10, 15, and 25 μmol/L) significantly suppressed the apoptosis, caspase-3 activity, reactive oxygen species level, and β amyloid (Aβ) content and increased the viability of these cells. OA (10 μmol/L) also increased the expression of stanniocalcin-1 (STC-1) and uncoupling protein-2 (UCP2) in N2a/APP695swe cells. STC-1 interference markedly reversed the effect of OA on UCP2, indicating that OA may regulate UCP2 expression in N2a/APP695swe cells via STC-1. Moreover, UCP2 inhibition significantly reversed the OA-mediated effects on cell viability, caspase-3 activity, reactive oxygen species, and Aβ level. Thus, OA regulates UCP2 expression via STC-1 to alleviate oxidative stress and Aβ level in N2a/APP695swe cells.     

Cholinergic activity and amyloid precursor protein processing in aging and Alzheimer's disease

Among the neuropathological features of Alzheimer's disease (AD), are senile plaques and dysfunction of cholinergic neurotransmission are the major hallmarks. Senile plaques are formed by amyloid beta-peptides (Abeta), derived from amyloidogenic processing of a larger protein named amyloid precursor protein (APP). It has been suggested and also proved that cholinergic system plays an important role in the cognitive function of the brain and its deficit correlates well with the cognitive impairment of AD. Aging is the most important risk factor for AD. In normal aging, cholinergic system undergoes degeneration. APP processing changes with aging, probably resulting in higher amyloidogenic products. The current clinical treatments for Alzheimer's disease solely rely on cholinomimetic drugs i.e., acetylcholinesterase inhibitors. Recently, a great effort has been made to seek therapies that could reduce Abeta products by influencing APP processing. Through genetic engineering in cell lines and mice, in vitro and in vivo models for AD studies have been created. Experimental evidence obtained from the studies on these model organisms suggests that activity of cholinergic neurotransmission might have an impact on APP processing. On the other hand, the proteolytic products of APP have also been found able to influence the cholinergic system in both in vitro and in vivo models. To determine whether there exists a reciprocal interaction between cholinergic neurotransmission and APP processing is important for the development of new therapeutic strategies with high efficacy and specificity for AD.     

Effect of serum cholesterol on the mRNA content of amyloid precursor protein in rat livers

Genes that showed mRNA content profiles, which correlated with serum concentrations of total cholesterol (T.CHO), were screened from the microarray data of phenobarbital (PB)- or clofibrate (CLO)-treated rat livers, and the correlation was evaluated based on Spearman's correlation coefficient. Many genes involved in the cholesterol or bile acid metabolism were highly correlated such as UDP-glucuronosyltransferase-21, apolipoprotein A-I and cMOAT. The mRNA content of the amyloid precursor protein (APP) showed the 5th highest correlation among the 8799 probes in the Affymetrix Rat Genome U34 Array. In the livers of rats fed a high-cholesterol (1%) diet for 33 days, serum T.CHO levels increased by 4.6-fold, and the hepatic APP mRNA content also increased by 1.9-fold compared to the control group. These data suggest that the hepatic APP mRNA content was affected by serum T.CHO, and that hepatic APP was involved in cholesterol metabolism in rat livers.     

阿尔茨海默病患者血清中Apelin13和FKBP5的表达水平及临床意义

目的 探究阿尔茨海默病（AD）患者血清中Apelin13和FK506结合蛋白51(FKBP5)的表达水平及意义。方法 选取93例AD患者（AD组）,同时选取同年龄层体检的90例健康者（对照组）。比较2组血清Apelin13、FKBP5mRNA水平差异。Pearson相关分析Apelin13、FKBP5 mRNA与简易精神状态量表（MMSE）评分的相关性。采用受试者工作特征（ROC）曲线评估Apelin13、FKBP5 mRNA对AD患者重度认知功能障碍的诊断价值。结果 AD组患者MMSE评分、血清Apelin13水平较对照组降低,而FKBP5 mRNA水平较对照组升高（均P<0.01）。轻、中及重度组AD患者血清中Apelin13水平依次降低,而FKBP5 mRNA水平依次升高（均P<0.05）。二元Logistic回归分析显示,较高的MMSE评分、Apelin13是AD发生的保护因素,而较高的FKBP5 mRNA是AD发生的危险因素（均P<0.05）。AD患者MMSE评分与血清FKBP5 mRNA水平呈负相关,而与Apelin13水平呈正相关（均P<0.05）...     

Neuroprotective effects of Foeniculum vulgare seeds extract on lead-induced neurotoxicity in mice brain

The present study investigates the neuroprotective effects of Foeniculum vulgare seeds in a lead (Pb)-induced brain neurotoxicity mice model. The dried seeds extract of Foeniculum vulgare was prepared with different concentrations of organic solvents (ethanol, methanol, n-hexane). The in vitro antioxidant activity of Foeniculum vulgare seed extracts was assessed through DPPH assay and the chemical composition of the extracts was determined by high-resolution ¹H NMR spectroscopy. The age-matched male Balb/c mice (divided into 9 groups) were administered with 0.1% Pb and 75% and 100% ethanol extracts of Foeniculum vulgare seeds at a dose of 200?mg/kg/day and 20?mg/kg/day. The maximum antioxidant activity was found for 75% ethanol extract, followed by 100% ethanol extract. Gene expression levels of oxidative stress markers (SOD1 and Prdx6) and the three isoforms of APP (APP common, 770 and 695), in the cortex and hippocampus of the treated and the control groups were measured. Significant increase in APP 770 expression level while a substantial decrease was observed for SOD1, Prdx6 and APP 695 expression in Pb-treated groups. Interestingly, the deranged expression levels were significantly normalized by the treatment with ethanol extracts of Foeniculum vulgare seeds (specifically at dose of 200?mg/kg/day). Furthermore, the Pb-induced morphological deterioration of cortical neurons was significantly improved by the ethanol extracts of Foeniculum vulgare seeds. In conclusion, the present findings highlight the promising therapeutic potential of Foeniculum vulgare to minimize neuronal toxicity by normalizing the expression levels of APP isoforms and oxidative stress markers.     

ApoE genotype influences the biological effect of donepezil on APP metabolism in Alzheimer disease: evidence from a peripheral model.

Three major amyloid precursor protein (APP) forms with apparent molecular weight ranging from 106 to 130 kDa are present in human platelets. Alzheimer disease (AD) is associated with a decreased APP forms ratio (APPr) between the three major forms. A total of 25 mild to moderate AD patients were investigated. Platelet APPr was studied before and after 30 days of acetylcholinesterase-inhibitor treatment (donepezil, 5 mg daily). Patients were grouped into non-epsilon4 carriers and epsilon4 carriers according to apolipoprotein E (ApoE) genotype. At baseline, all patients showed low APPr levels and no significant difference was found between the two ApoE subgroups. After treatment, although a marked improvement in APPr was observed in most patients, non-epsilon4 carriers displayed a higher increase compared to epsilon4 carriers (P<0.0001). The present study provides evidence that donepezil influences APP metabolism in platelets, and suggests that ApoE genotype might be an important modulating factor for drug responsiveness in AD.     

Serum histamine in Alzheimer's disease and multi-infarct dementia.

Recent data indicate that a neuroimmune reaction might be responsible in part for neuronal death and cognitive deterioration in senile dementia. The potential involvement of brain histamine (HA) and interleukin-1 (IL-1) in this process has been previously documented. We have studied the concentration of serum HA in patients with Alzheimer's disease (AD) or multi-infarct dementia (MID) and in age-matched control subjects. Serum HA levels were significantly higher in AD (10.935 +/- 5.692 nM) and MID (8.521 +/- 3.44 nM) than in controls (5.533 +/- 2.567 nM) and correlated with mental performance as evaluated with the Mini-Mental State Examination (MMSE) (r = +0.493, p < 0.009). No correlation was found with cardiovascular parameters, cerebrovascular risk factors or age. Hyperactivation of the histaminergic system in AD at central and peripheral levels might reflect a neuroimmune reaction to brain tissue damage, a neurotrophic response, and/or a reactive process to regulate the IL-1 induced amyloid precursor protein (APP) overproduction.     

异香豆素对阿尔茨海默病Aβ蛋白的抑制作用及其机制

目的:探讨异香豆素对阿尔茨海默病Aβ的影响及其相应作用机制。方法:脂质体转染构建APP695高表达CHO细胞系;MTT实验检异香豆素对CHO/APP695的细胞毒作用;RT-PCR检测APP695的表达;Western-blot实验检测目的蛋白的表达;放射免疫法测定细胞培养上清Aβ含量;ELISA法测定γ-分泌酶活性变化。结果:RT-PCR和Western-blot检测显示CHO/APP695细胞高表达APP蛋白;0,10,20,40μmol·L-1的异香豆素处理CHO/APP695细胞24 h后,Aβ的分泌量从(16.4±1.4)pg.mL-1依次减低为(12.6±1.1),(9.4±0.8),(4.7±0.6)pg·mL-1,各组间差异有统计学意义(P<0.05);Western-blot结果显示异香豆素对CHO/APP695细胞APP蛋白的表达没有影响;ELISA测定显示10、20、40μmol·mL-1的异香豆素分别抑制了(21.4±1.6)%、(41.1±2.5)%和(73.6±5.2)%的γ-分泌酶活性;Western-blot结果显示异香豆素没有减少剪切的Notch1蛋白的表达。结论:异香豆素可以高效的抑制γ-分泌酶对APP蛋白的剪切,减少Aβ的生成,其抑制活性并不影响Notch1蛋白的剪切。     

Ibuprofen modifies cognitive disease progression in an Alzheimer's mouse model

Prolonged use of non-steroidal anti-inflammatory drugs (NSAIDs) may reduce the risk of developing Alzheimer's disease (AD) and delay disease onset. Negative results of clinical AD trials were rationalised by the discovery that certain NSAIDs reduce amyloid-beta( 1-42) (A beta(1- 42)) peptide production, the proposed central culprit in AD pathophysiology and main constituent of amyloid plaques, whereas other compounds do not affect A beta levels. Latter observations motivated further in-vitro and in-vivo research regarding the applicability of NSAIDs in treating and/or preventing AD. We used the age-dependent cognitive decline in the APP23 transgenic mouse model for AD to evaluate disease-modifying efficacy of chronic ibuprofen treatment at the cognitive level. At age 6 weeks, heterozygous APP23 mice and control littermates were subcutaneously implanted with osmotic pumps delivering saline or ibuprofen (50 mg/kg daily). After 2 months of treatment, a 3-week washout period prevented bias from potential symptomatic effects before cognitive evaluation commenced. Ibuprofen-treated APP23 mice performed significantly better than their sham-treated counterparts and almost attained the same level of performance as control animals on a complex visual-spatial learning task. This study clearly reports disease-modifying efficacy of ibuprofen at the cognitive level in transgenic mice modelling AD.     

Current status and perspectives on the development of therapeutic agents for Alzheimer's disease

Acetylcholinesterase inhibitors have beneficial effects to improve the cognitive impairment in patients with mild to moderate Alzheimer's disease (AD). In addition, a channel blocker of N-methyl-D-aspartate receptor, memantine hydrochloride, was approved as a therapeutic agent for patients with moderate to severe AD in both EU countries in 2002 and USA in 2003, while the clinical development is still ongoing in Japan. In contrast, the pharmacotherapy for a prime cure against AD is not available in the market, although there has been a worldwide search for novel compounds. The most plausible mechanism for the treatment of AD is the reduction of the amyloid beta-peptide (Abeta) plaques, one of the pathological markers of AD, in the brain. For this purpose, the inhibitors of beta-secretase and gamma-secretase, which cleave amyloid precursor protein (APP) to release Abeta, has been developed to interfere with APP processing. The beta-sheet breaker and metal chelators for the breakdown of aggregated Abeta have also been synthesized as well as the immunotherapeutic approach using Abeta vaccine. On the other hand, some nonsteroidal anti-inflammatory drugs, such as ibuprofen and sulindac, noncompetitively inhibited Abeta production but not Notch cleavage. The development of Abeta-lowering drugs is highly expected for the treatment of AD.     

Interleukin-1 in Alzheimer's disease and multi-infarct dementia: neuropsychological correlations.

It has been reported that patients with Alzheimer's disease (AD) exhibit an overproduction of interleukin-1 (IL-1) in the cerebrospinal fluid and brain tissue. Since IL-1 appears to promote the expression of the beta-amyloid precursor protein (APP) gene, we have investigated the concentrations of serum IL-1 alpha and IL-1 beta and AD and multi-infarct dementia (MID) in order to evaluate whether IL-1 acts as a peripheral activating factor on cerebrovascular endothelial cells stimulating APP production. Serum IL-1 alpha levels did not differ significantly between healthy elderly subjects (110.7 +/- 23.3 pg/ml), early-onset AD (EOAD; 112.5 +/- 23.3 pg/ml), late-onset AD (LOAD; 89.2 +/- 17.6 pg/ml) or MID (116.8 +/- 50.4 pg/ml) patients. Serum IL-1 beta levels were also similar in controls (223.7 +/- 55.7 pg/ml), EOAD (223.1 +/- 79.5 pg/ml), LOAD (212.5 +/- 58.9 pg/ml) and MID (199.4 +/- 29.0 pg/ml). In LOAD a negative correlation between mental performance (MMS score), IL-1 alpha (r = -0.7728; p less than 0.0715) and IL-1 beta (r = -0.9214; p less than 0.0011) was observed. These results indicate that serum IL-1 levels are not altered in AD and MID; therefore, it is unlikely that blood-borne IL-1 influences APP production in the central nervous system (CNS). In conclusion, the neuroimmune dysfunction present in AD seems to be mainly concentrated in the CNS, with only minor immune alterations at the peripheral level.     

抑郁症患者外周血中大麻素受体1和脂肪酸酰胺水解酶的mRNA表达水平及意义

目的 探讨抑郁症患者外周血中大麻素受体1(CB1)和脂肪酸酰胺水解酶(FAAH)的mRNA表达水平及意义.方法 选择43例未经治疗的抑郁症患者(抑郁组)和43例健康志愿者(健康组),采用实时荧光定量反转录聚合酶链式反应(RT-PCR)技术检测两组患者外周血中CB1和FAAH的mRNA表达水平,观察抑郁症患者与健康人群的CB1和FAAH水平变化;采用汉密尔顿抑郁量表(HAMD)和Stroop色词测试对抑郁症患者的抑郁程度和认知功能进行评估,分析CB1和FAAH表达水平与测试结果的相关性.结果 (1)抑郁症患者的CB1-mRNA、FAAH-mRNA表达水平均明显低于健康组(P＜0.05);(2)抑郁症患者的CB1表达水平与HAMD中的体质量变化因子正相关(r=1.021,P=0.001);FAAH表达水平与HAMD中的认知障碍因子负相关(r=-0.065,P=0.023);(3)抑郁症患者FAAH-mRNA表达水平影响患者的注意力和反应能力(P＜0.05).结论 CB1受体可以影响抑郁症患者的能量代谢,FAAH会对抑郁症患者的认知障碍产生影响,提示抑郁症患者外周血CB1-mRNA、FAAH-mRNA表达量与抑郁障碍具有相关性.     

Anti-amyloidogenic effects of ID1201, the ethanolic extract of the fruits of Melia toosendan,through activation of the phosphatidylinositol 3-kinase/Akt pathway

Amyloid beta (Aβ) peptides, which are generated from amyloid precursor protein (APP), are thought to play a major role in the pathogenesis of Alzheimer's disease (AD). This study investigated the anti-amyloidogenic effects of the ethanolic extract of Meliae Fructus (ID1201) using human embryonic kidney 293 cells with stably expressed human wild-type or Swedish mutant APP695 and β-secretase 1. ID1201 treatment enhanced the non-amyloidogenic metabolism of APP; increases in soluble APPα levels and decreases in soluble APPβ and Aβ levels resulted from the α-secretase activation through the phosphatidylinositol 3-kinase (PI3K)/Akt pathway. In addition, ID1201-treated 5 × familial AD (FAD) mice with 5 mutations in APP and presenilin 1 showed reduced levels of Aβ and amyloid plaques in the brain relative to those of 5 × FAD mice with vehicle treatments. These results indicate that ID1201 possesses anti-amyloidogenic effects via the activation of the PI3K/Akt pathway, suggesting that it is a potential therapeutic agent for AD.     

轻度认知功能障碍与阿尔茨海默病患者血管危险因素的研究

目的 探讨血管危险因素与轻度认知功能障碍（Mild cognitive impairment,MCI）及阿尔茨海默病（Alzheimer＇sdisease,AD）的关系,并进一步分析各因素与认知功能下降程度的相关性.方法 选择2012年6月至2014年6月于门诊及住院部诊断为MCI及AD的患者各35例,同期体检的性别、年龄、文化程度相匹配的健康老人35例为对照.所有研究对象均进行MMSE、ADAS-Cog量表评定,采集晨空腹血进行血脂、血糖检测,并分别记录性别、年龄、身高、体重、吸烟、饮酒等情况.采用最小显著性差异法（LSD）比较各组间血管危险因素的差异、Pearson＇s相关分析各因素与认知功能评分的相关性.结果 与对照组相比,MCI组、AD组体重指数、血胆固醇水平呈进行性下降,但仅AD组与对照组相比差异有统计学意义.收缩压水平MCI组、AD组与对照组相比均明显升高,MCI组与AD组比较差异亦有统计学意义.Pearson＇s分析可见各因素与认知功能下降程度之间呈线性相关.糖尿病、饮酒比率AD组与对照组相比亦明显升高.结论 血管危险因素在老年人认知功能下降过程中有重要的作用,并有可能指导AD早期诊断及治疗.