Functional Vitamin E deficiency in ApoE4 patients with Alzheimer's disease

Oxidative stress has been implicated in the development of Alzheimer's disease (AD). Consequently, antioxidant therapies including Vitamin E (VitE) supplementation for both prevention and treatment of neurodegenerative diseases currently appears to be a promising avenue of research. The aim of the present study was to examine the relationship between AD and the ApoE phenotype, lipid parameters and VitE levels in a large cohort of elderly subjects. No absolute deficit was observed in plasma VitE levels. However in AD, ApoE4 is not associated with an increase in total cholesterol (TC) and VitE levels. Moreover, our results suggest that oxidative stress-induced injury and protection by VitE in AD are related to the ApoE phenotype. Our study strongly supports the hypothesis of an impairment of lipophilic antioxidant delivery to neuronal cells in AD leading to a tissular antioxidant deficiency which could facilitate oxidative stress.     

ApoE与阿尔茨海默病

载脂蛋白E（ApoE）基因型是现在所知的散发型和迟发型阿尔茨海默症的最大的危险因子,它是中枢神经系统中主要的胆固醇运载体,同时又是极低密度脂蛋白（VLDL）的组成成分。ApoE对脑内胆固醇代谢异常和β-淀粉样蛋白沉积等阿尔茨海默症的典型特征有重要作用,对于ApoE在阿尔茨海默症中生化作用机制的研究对于我们对其发病机理的深入认识及治疗有重要意义。     

Interaction of the H63D mutation in the hemochromatosis gene with the apolipoprotein E epsilon 4 allele modulates age at onset of Alzheimer's disease

The H63D mutation in the hemochromatosis gene (HFE) has recently been considered as a risk factor in Alzheimer's disease (AD) with advancing age at onset of the disease, independently of the apolipoprotein E (ApoE) epsilon4 allele effect. We examined the distribution of the H63D mutation and ApoE genotypes as a function of age at AD onset in 328 patients with sporadic AD. Our data show that the mutant H63D allele potentially interacts with the ApoE epsilon4 allele to significantly reduce age at onset of AD compared to ApoE epsilon4 carriers alone, but has no effect on age at onset in ApoE epsilon4 non-carriers.     

载脂蛋白D基因多态与散发性阿尔茨海默病的相关性

目的 通过检测载脂蛋白D基因(apolipoprotein D gene,ApoD)单核苷酸多态位点,探讨其与北方汉族人群散发性阿尔茨海默病(sporadic Alzheimer's disease,SAD)的相关性.方法 应用聚合酶链反应(PCR)及直接测序筛查ApoD基因所有外显子及其两端内含子多态位点.选取等位基因频率大于10%的位点,利用PCR-限制性片段长度多态性(PCR-RFLP)技术,采用病例-对照相关性研究方法 ,研究256例SAD患者以及294名健康人的ApoD多态位点与SAD发病的关系.同时对位点间的连锁不平衡及构建的单体型进行相关性分析.结果 ApoD第2号外显子存在T/C多态性(rs5952),第3号内含子(rs1568566)存在C/T多态性.ApoD rs5952 T/C和rs1568566 C/T等位基因频率和基因型频率在SAD组和对照组间的分布差异有统计学意义.Logistic回归分析表明携带rs5952C或rs1568566T等位基因分别增加SAD发病风险:校正后rs5952 χ2=9.282(P=0.002);rs1568566 χ2=5.072(P=0.024).进一步分析证实性别和ApoD多态性存在交互作用.rs5952-rs1568566位点间存在连锁不平衡.结论 北方汉族人ApoD基因存在第2号外显子rs5952和第3号内含子rs1568566 2个多态位点;ApoD多态可增加SAD发病风险;携带rs5952T或rs1568566C单体型可能对SAD的发病有一定的保护作用.     

Alpha-1-antichymotrypsin gene polymorphism and risk for sporadic Alzheimer's disease in a German population

The A allele of a common A-T polymorphism in the signal peptide of alpha(1)-antichymotrypsin gene (ACT) has been reported to contribute a two- to threefold increased risk to Alzheimer's disease (AD) patients who carry the apolipoprotein E epsilon4 (APOE epsilon4) genotype. Since the ACT expression in AD brains is enhanced in particular in areas that develop amyloid plaques, the ACT polymorphism is considered to be a good candidate gene. We have analyzed this polymorphism in 102 AD patients and 191 matched controls, all originating from Western Germany. No statistically significant differences in allele frequencies and in genotype distribution of ACT could be shown between AD patients and controls. When we analyzed the polymorphism in APOE epsilon4 carriers, no overrepresentation in our AD group could be shown for the ACT*AA genotype carriers. Copyrightz1999S.KargerAG,Basel     

Association of the H63D polymorphism in the hemochromatosis gene with sporadic ALS

Iron misregulation promotes oxidative stress and abnormally high iron levels have been found in the spinal cords of patients with ALS. The authors investigated whether HFE gene polymorphisms, linked to hemochromatosis, are associated with ALS using two independent populations of patients with sporadic ALS and controls (totaling 379 patients and 400 controls). They found that the H63D polymorphism is overrepresented in individuals with sporadic ALS (odds ratio 1.85, CI: 1.35 to 2.54).     

Apolipoprotein E genotype of a Portuguese control population and Alzheimer's disease patients

The present work first describes the frequency of APOE alleles and genotypes in Portuguese populations in relation to AD pathology. We genotyped a group of late onset sporadic AD cases, their pairwise controls and a larger group of randomly selected individuals, to assess the distribution pattern of APOE alleles in the Portuguese population. APOE ?4 relative frequency may significantly vary among different populations—a fact which should be taken into consideration for the correct evaluation of the cossegregation of this allele with AD pathology. We observed a frequency of 0.087 ± 0.029 of the APOE ?4 and 0.043 ± 0.021 of the APOE ?2 allele in the Portuguese random population which as expected showed a marked prevalence of the APOE ?3 form (0.870 ± 0.035). In the AD patients the APOE ?4 allele frequency was significantly higher (0.360 ± 0.081) than in the controls (χ₂ = 31.000, p < 0.00001, df = 2). Consistently APOE ?3 allele frequency (0.640 ± 0.081) was significantly lower than in the controls while APOE ?2 was absent in the studied AD population. Taken together our results demonstrate that the Portuguese population is characterized by a relatively low frequency of the APOE ?4 allele, in good agreement with previous observations of a gradient of ?4 allele frequency in Europe, decreasing from North to South. Several lines of evidence point at APOE?e4 allele as a major genetic susceptibility factor in AD. The APOE ?4 allele was significantly higher [odds ratio (OR) = 5.93, 95% CI 3.55–9.91] in the Portuguese AD patients than in the random non-demented population. The genotype analysis of the Portuguese AD patients here described reveals a marked, increased frequency of ?4 homo- and heterozygous individuals consistent with an APOE ?4 zigosity effect as a further genetic trait predisposing to AD development.     

中国人群ApoE基因多态性与迟发性阿尔茨海默病关系的Meta分析

目的探讨中国人群载脂蛋白E(Apo E)基因多态性与迟发性阿尔茨海默病的关系。方法以载脂蛋白E基因(Apo E)、迟发性阿尔茨海默病(late onset Alzheimer's disease)、基因多态性(polymorphism)、China和Chinese等中英文词组,检索美国国立医学图书馆生物医学信息检索系统、荷兰医学文摘、EBSCO-CINAHL、Cochrane图书馆,以及中国生物医学文献数据库、中国知网中国知识基础设施工程、万方数据库等近20年发表的关于中国人群Apo E基因多态性与迟发性阿尔茨海默病关系的病例对照研究,采用Newcastle-Ottawa量表(NOS)进行文献质量评价,Rev Man 5.0统计软件进行Meta分析。结果共获得249篇文献,经剔除重复和不符合纳入标准者并补充相关文献,最终纳入13篇高质量临床研究(NOS评分≥5分),共3372例受试者(迟发性阿尔茨海默病患者1360例、对照者2012例)。Meta分析显示:携带Apo Eε4等位基因者发生迟发性阿尔茨海默病的风险高于携带Apo Eε3等位基因者(OR=3.710,95%CI:2.960~4.640;P=0.000);表现为Apo Eε3/ε4(OR=3.160,95%CI:2.390~4.180;P=0.000)、Apo Eε2/ε4(OR=3.410,95%CI:2.160~5.380;P=0.000)和Apo Eε4/ε4(OR=16.400,95%CI:8.200~32.810;P=0.000)基因型者发生迟发性阿尔茨海默病的风险高于Apo Eε3/ε3基因型者。结论携带Apo Eε4等位基因,以及Apo Eε3/ε4、Apo Eε2/ε4和Apo Eε4/ε4基因型是中国人群发生迟发性阿尔茨海默病的危险因素。     

Cathepsin D polymorphism in Italian elderly subjects with sporadic late-onset Alzheimer's disease

Alzheimer's disease (AD) is the most frequent cause of dementia in elderly people. Different pathological pathways have been involved in the development of late-onset AD. Among them, numerous genes have been proposed as pathogenetic factors acting independently or interactively. It has been suggested that the cathepsin D gene (CTSD) is associated with late-onset AD. We analyzed an exonic polymorphism of the CTSD gene [C-->T (Ala-->Val) transition at position 224] in 142 AD patients and 120 controls. Our data indicate no significant association between this polymorphism and the risk of AD. Likewise there was no association between CTSD polymorphism and the apolipoprotein E genotype in the risk of developing AD.     

Association between cathepsin D polymorphism and Alzheimer's disease in a Chinese Han population

Cathepsin D (CTSD) is an intracellular aspartyl protease, which is active in the endosomal/lysosomal system. CTSD may play a role in Alzheimer's disease (AD) through cleaving the amyloid precursor protein into beta-amyloid peptide and degrading tau protein into fragments. A functional polymorphism in exon 2 of the cathepsin D gene (C-->T, Ala224Val) has recently been reported to increase the risk for AD in some of the Caucasian populations, with a significant overrepresentation of the T allele, but these reports have not been universally duplicated. We performed an association study between CTSD polymorphism and AD in 156 sporadic AD patients and 183 controls of Chinese Han ethnicity. Our data revealed that the distribution of CTSD genotypes and alleles was similar in patients and controls. No direct association was found between CTSD polymorphism and AD risk. There might be a weak synergistic interaction between CTSD T and APOEepsilon4 allele in increasing the risk for developing AD.     

Gender effect on apolipoprotein E 84 allele-associated risk for sporadic Alzheimer's disease

Introduction - The role of gender in Alzheimer's disease (AD), and its possible interaction with apolipoprotein E (apoE), has been controversial. Material and methods - ApoE allelic frequencies and the effect of apoE 4 allele dosage on risk and age at onset of AD were evaluated, separately for men and women, in 100 patients with sporadic AD and 100 age-matched controls. Results - The distribution of apoE alleles and the odds ratio for AD, when associated with 1 or 2 4 alleles, were not statistically different between men and women. No effect of the dosage of the 4 allele was found on the age at onset of dementia in the 2 sex groups. Conclusion - Our data suggest that the relation of the apoE genotype to AD is not dependent on sex.     

The association between H63D mutations in HFE and amyotrophic lateral sclerosis in a Dutch population

BACKGROUND: Mutations in HFE, a gene defect that can disrupt iron metabolism, have been implicated in increasing the risk of developing amyotrophic lateral sclerosis (ALS). OBJECTIVE: To further establish the association between ALS and HFE mutations by investigating whether HFE mutations are associated with an increased risk of developing ALS in a population in The Netherlands and by pooling our results with those from previous studies. DESIGN: Retrospective study. SETTING: Tertiary referral center for neuromuscular disorders. PARTICIPANTS: Genotyping for 2 common HFE mutations was performed in 289 patients with ALS and 5886 population-based controls in The Netherlands between January 1, 2000, and December 31, 2004. MAIN OUTCOME MEASURES: Development of ALS and clinical phenotype were compared among the different HFE genotypes, adjusting for known prognostic factors such as age at onset and sex. RESULTS: Homozygosity for H63D was associated with an increased risk of developing ALS (odds ratio [OR], 2.2; 95% confidence interval [CI], 1.1-4.1). After pooling our results with those from previous studies, a positive association between H63D homozygotes (OR, 2.7; 95% CI, 1.7-4.4), heterozygotes (OR, 1.5; 95% CI, 1.0-2.1), and mutation carriers (OR, 1.7; 95% CI, 1.1-2.5) was found. Within the patient group, heterozygosity for the H63D mutation was associated with a higher age at onset. CONCLUSIONS: These findings suggest that H63D mutations in HFE play a role in the pathogenesis of ALS in various populations. This association might involve a later-onset subset of ALS.     

H63D polymorphism in the hemochromatosis gene is associated with sporadic amyotrophic lateral sclerosis in China

Background and purpose: The H63D polymorphism in the hemochromatosis (HFE) gene has been reported as a risk factor for amyotrophic lateral sclerosis (ALS) in Europe and America, but no data have been reported for Asia. Here, we investigated the possible association between H63D and sporadic ALS (sALS) in a Chinese Han population. Methods: A total of 195 individuals with sALS from three centers in China and 405 unrelated healthy controls were recruited. All subjects were genotyped by restriction fragment length polymorphism (RFLP) analysis. Results: Sporadic ALS was significantly related to the H63D polymorphism in heterozygous carriers (odds ratio 3.10, 95%CI: 1.49–6.47, P = 0.002). Conclusions: The HFE H63D polymorphism may contribute to the development of sALS in Chinese.     

Sex,ApoE4 and Alzheimer's disease: rethinking drug discovery in the era of precision medicine

正Alzheimer's disease(AD) is the most common cause of dementia and presents with an insidious onset and long prodromal period. Despite billions spent on clinical trials and decades of research, there are currently no disease modifying therapies approved for AD.     

Alzheimer's disease and apolipoprotein e-4 allele in an amish population

Alzheimer's Disease (AD) is a complex genetic disorder with four loci already identified. Mutations in three of these, the amyloid precursor protein, presenilin I, and preseuilin II, cause early-onset AD. The apolipoprotein E (APOE) gene contributes primarily to late-onset AD. The APOE-4 allele acts in a doserelated fashion to increase risk and decrease the age-of-onset distribution in AD. We examined the effect of APOE on AD in a previously unstudied Amish population that has a lower prevalence of dementia compared with other populations. We sampled a large inbred family with 6 latehyphen: onset AD members. We also genotyped 53 individuals from the general Amish population as controls for the APOE allele frequency estimates. The frequency of the APOE-4 allele in the Amish controls was 0.037 ± 0.02. This differed significantly compared with three independent sets of non-Amish white controls (p < 2 × 10?4, p < 6 × 10?5, and p < 2 × 10?6). In addition, all Amish AD-affected individuals had APOE 3/3 genotypes; no APOE X/4 or 4/4 individuals were observed. We suggest that the lower frequency of dementia in the Amish may be partially explained by the decreased frequency of the APOE?4 allele in this population, and that the inbred nature of this pedigree, with its strong clustering of cases contrasted against the lower frequency of dementia, indicates that additional genetic factors influence late-onset AD.     

Brain metabolic decreases related to the dose of the ApoE e4 allele in Alzheimer's disease

OBJECTIVES: Declines in brain glucose metabolism have been described early in Alzheimer's disease (AD), and there is evidence that a genetic predisposition to AD contributes to accelerate this process. The epsilon 4 (e4) allele of the apolipoprotein E (ApoE) gene has been implicated as a major risk factor in this process. The aim of this FDG-PET study was to assess the ApoE e4 dose related effect on regional cerebral glucose metabolism (METglc) in clinical AD patients, with statistical voxel based methods. METHODS: Eighty six consecutive mild to moderate AD patients included in the Network for Efficiency and Standardisation of Dementia Diagnosis database underwent FDG-PET scans at rest. PCR was used to determine the ApoE genotype. Patients were grouped as e4 non-carriers (n = 46), e3/e4 (n = 27) and e4/e4 (n = 13) carriers. A voxel-based mapping program was used to compare each AD subgroup with a database of 35 sex and age matched controls (p<0.001, corrected for cluster extent) and also to compare between the subgroups (p<0.001, uncorrected). RESULTS: No difference was found as to age at examination, age at onset, sex, disease duration, educational level, or severity of dementia between AD subgroups. Compared with controls, all AD subgroups had equivalent METglc reductions in the precuneus, posterior cingulate, parietotemporal, and frontal regions. Direct comparisons between AD subgroups indicated that patients with at least one e4 allele had METglc reductions within additional associative and limbic areas compared with e4 non-carriers. CONCLUSIONS: The present FDG-PET study showed different metabolic phenotypes related to the ApoE genotype in clinical AD patients, as revealed with voxel based statistical methods. The results suggest a generalised disorder in e4 carriers impairing metabolism globally, in addition to the more localised changes typical of AD patients.