A study on factors associated with age of Alzheimer's disease onset / 中华流行病学杂志

Objective: To understand the distribution characteristics of age of Alzheimer's disease (AD) onset and influencing factors. Methods: Based on the follow-up data of Alzheimer's Disease Neuroimaging Initiative from 2005 to 2022, participants with normal cognition (CN) or mild cognitive impairment (MCI) at baseline survey, and those with progression to AD during follow-up period were selected as study subjects. Univariate analysis and multiple linear regression analysis were performed to explore the associations of gender, race, number of ApoE ε4 genes carried, family history, years of education and marital status with the age of AD onset. Results: A total of 405 participants, with an average age of (74.0±6.9) years at baseline survey, progressed to AD during follow up period. The age of AD onset was (76.6±7.5) years, and age of onset in men was about 1.9 years later than women. Multiple linear regression analysis showed that for each increase in ApoE ε4 gene number, the age of AD onset was about 0.344 years earlier. The age of AD onset was 4.007 years earlier for those with MCI at baseline survey compared with those with CN. Years of education were not significantly associated with the age of onset of AD (P>0.05). Conclusion: Those who carry ApoE ε4 gene, and have MCI at baseline survey might have earlier age of AD onset.

Human 8-cell embryos enable efficient induction of disease-preventive mutations without off-target effect by cytosine base editor

Approximately 140 million people worldwide are homozygous carriers of APOE4 (ε4), a strong genetic risk factor for late onset familial and sporadic Alzheimer's disease (AD), 91% of whom will develop AD at earlier age than heterozygous carriers and noncarriers. Susceptibility to AD could be reduced by targeted editing of APOE4, but a technical basis for controlling the off-target effects of base editors is necessary to develop low-risk personalized gene therapies. Here, we first screened eight cytosine base editor variants at four injection stages (from 1- to 8-cell stage), and found that FNLS-YE1 variant in 8-cell embryos achieved the comparable base conversion rate (up to 100%) with the lowest bystander effects. In particular, 80% of AD-susceptible ε4 allele copies were converted to the AD-neutral ε3 allele in human ε4-carrying embryos. Stringent control measures combined with targeted deep sequencing, whole genome sequencing, and RNA sequencing showed no DNA or RNA off-target events in FNLS-YE1-treated human embryos or their derived stem cells. Furthermore, base editing with FNLS-YE1 showed no effects on embryo development to the blastocyst stage. Finally, we also demonstrated FNLS-YE1 could introduce known protective variants in human embryos to potentially reduce human susceptivity to systemic lupus erythematosus and familial hypercholesterolemia. Our study therefore suggests that base editing with FNLS-YE1 can efficiently and safely introduce known preventive variants in 8-cell human embryos, a potential approach for reducing human susceptibility to AD or other genetic diseases.

Polimorfismos del gen de la apolipoproteína E en adultos mayores de 60 años con disminución de la memoria cognitiva y enfermedad de Alzheimer en diferentes poblaciones venezolanas / Apolipoprotein E polymorphisms in adults over 60 years of age with mild cognitive impairment and Alzheimer's disease in different Venezuelan populations

Introducción. La enfermedad de Alzheimer constituye un problema de salud pública que tiende a agravarse en el tiempo. Entre los factores genéticos de predisposición más importantes, se encuentra la presencia del alelo ε4 del gen APOE que codifica para la apoproteína E. Objetivo. Determinar las frecuencias alélicas y genotípicas de las isoformas de APOE en adultos mayores de 60 años con memoria cognitiva disminuida y Alzheimer, en la gran Caracas y en la comunidad indígena pemón de la zona Kamarata-Kanaimö, Estado Bolívar. Materiales y métodos. Se estudiaron 267 pacientes: 96 controles, 40 con memoria cognitiva disminuida y 108 con Alzheimer procedentes de Caracas, y 23 individuos de Kamarata-Kanaimö. Las isoformas de APOE se determinaron con el estuche AP1210Z: Seeplex ApoE genotyping™. Resultados. El alelo ε4 mostró asociación significativa con la memoria cognitiva disminuida (OR=5,03; IC95% 0,98-25,70) y la enfermedad de Alzheimer (OR=5,78; IC95% 1,24-26,85). Las frecuencias genotípicas de los grupos de control y con memoria cognitiva disminuida, fueron:ε3/ε3> ε3/ε4> ε2/ε4> ε3/ε2> ε4/ε4, y las del grupo con Alzheimer: ε3/ε3> ε3/ε4> ε4/ε4> ε2/ε4> ε3/ε2. En Kamarata-Kanaimö, el orden fue ε3/ε3> ε3/ε4> ε4/ε4 y no se encontró el alelo ε2. Conclusiones. Las frecuencias alélicas y genotípicas de APOE en la muestra tuvieron una distribución similar a la de otros estudios en Venezuela y las Américas. La ausencia del alelo ε2 en la comunidad indígena de Kamarata-Kanaimö amerita mayor investigación. Se constató la asociación positiva del alelo ε4 en personas con la enfermedad de Alzheimer y con memoria cognitiva disminuida. Conocer precozmente los pacientes portadores de este alelo puede ayudar a establecer medidas preventivas en nuestra población.

Introduction: Alzheimer's disease represents a serious public health problem that tends to worsen over time. Among the most important genetic predisposing factors is the presence of the ε4 allele of the apoprotein E gene (APOE). Objective: To determine the allelic and genotypic frequencies of the APOE isoforms in adults over 60 years old with mild cognitive impairment and Alzheimer's disease in Gran Caracas and in the indigenous Pemón community of the Kamarata-Kanaimö area, Bolívar State. Materials and methods: We studied 267 patients: 96 controls, 40 with mild cognitive impairment, 108 with Alzheimer's from Caracas, and 23 individuals from Kamarata-Kanaimö. The APOE isoforms were determined with the AP1210Z: Seeplex® ApoE Genotyping kit. Results: The allele ε4 showed a significant association with mild cognitive impairment (OR=5.03; 95% CI: 0.98-25.70) and EA (OR=5.78; 95% CI: 1.24-26.85). The genotype frequencies for the control and mild cognitive impairment groups were ε3/ε3> ε3/ε4> ε2/ε4> ε3/ε2> ε4/ε4, and for the Alzheimer's group, ε3/ε3> ε3/ε4> ε4/ε4> ε2/ε4> ε3/ε2 In Kamarata-Kanaimö, the order was ε3/ε3> ε3/ε4> ε4/ε4; the allele ε2 was not found in this group. Conclusions:APOE allelic and genotypic frequencies in our sample showed a similar distribution to those found in other studies in Venezuela and the Americas. The absence of the ε2 allele in the indigenous community of Kamarata-Kanaimö warrants further investigation. The positive association of the ε4 allele with both Alzheimer's and mild cognitive impairment was reinforced. The early determination of the ε4 allele carriers can help establish preventive measures in our population.

Factors Influencing Alzheimer's Disease Risk: Whether and How They are Related to the APOE Genotype / 神经科学通报·英文版

Alzheimer's disease (AD) is the most prevalent neurodegenerative disease featuring progressive cognitive impairment. Although the etiology of late-onset AD remains unclear, the close association of AD with apolipoprotein E (APOE), a gene that mainly regulates lipid metabolism, has been firmly established and may shed light on the exploration of AD pathogenesis and therapy. However, various confounding factors interfere with the APOE-related AD risk, raising questions about our comprehension of the clinical findings concerning APOE. In this review, we summarize the most debated factors interacting with the APOE genotype and AD pathogenesis, depict the extent to which these factors relate to APOE-dependent AD risk, and discuss the possible underlying mechanisms.

Estado nutricional de indivíduos com Comprometimento Cognitivo Leve e Doença de Alzheimer em relação ao Selênio e sua associação com parâmetros que predispõem ao declínio cognitivo / Nutritional status of subjects with mild cognitive impairment and Alzheimer's disease in relation to selenium and its association with paramenters that predispose to cognitive decline

A Doença de Alzheimer (DA) é a principal forma de demência e um dos grandes desafios no sistema de saúde do século 21. O Comprometimento Cognitvo Leve (CCL) é um estágio que antecede a DA e que compartilha algumas vias metabólicas em comum. A fisiopatologia da DA é caracterizada pela ampla morte neuronal e pela presença de placas neuríticas e emaranhados neurofibrilares, respectivamente relacionadas ao acúmulo de peptídeo beta amiloide (Aß) em tecidos cerebrais e alterações no citoesqueleto que se originam da hiperfosforilação da proteína tau nos neurônios. Algumas linhas de evidência sustentam a hipótese de que o estresse oxidativo, nitrosativo e a inflamação tenham um papel importante na patogênese tanto do DA como do CCL. O selênio, mineral essencial ao ser humano, encontra-se incorporado ao sítio ativo de 25 selenoproteínas, das quais pelo menos um terço apresenta papel antioxidante, além de potencialmente modularem o sistema inflamatório. Deste modo, o estado nutricional adequado dos indivíduos relativo ao selênio, parece exercer efeito neuroprotetor, reduzindo o risco para o CCL e DA e retardando a progressão destas doenças. A entrega de selênio para o cérebro se dá pela interação da selenoproteína P (SELENOP) com o receptor de apolipoproteína E2 (ApoER2). A apolipoproteína E (ApoE) também interage com o ApoER2 no metabolismo de lipídeos. Assim, pode-se pensar que indivíduos portadores do polimorfismo do gene da apolipoproteína E ε4 (APOE ε4), o principal polimorfismo genético para o aumento no risco de desenvolvimento de DA, possam ter essa entrega de selênio prejudicada para o cérebro uma vez que os receptores ApoER2 dos portadores do polimorfismo de APOE ε4 são sequestrados para compartimentos intracelulares, sendo menos expressos na membrana plasmática e portanto diminuindo a interação com a SELENOP. Este trabalho teve por objetivo avaliar se a distribuição do selênio no plasma e líquor de indivíduos portadores de CCL e DA é afetada pelo alelo APOE ε4, avaliar se o estado nutricional do indivíduo em relação ao selênio afeta marcadores de assinatura biológica para DA (peptídeo beta amilóide, proteína tau e proteína tau fosforilada) e concentrações de citocinas inflamatórias. Para tanto, foram selecionadas amostras de plasma e líquor do banco de material biológico do Instituto de Psiquiatria da FMUSP, sendo 14 indivíduos do grupo CCL, 28 indivíduos do grupo DA e 28 indivíduos controles, de ambos os gêneros, com idade acima de 60 anos e residentes na cidade de São Paulo. Foram avaliados os seguintes marcadores: concentrações de selênio no plasma e líquor, concentrações SELENOP no plasma e líquor, citocinas inflamatórias, fator neurotrófico derivado do cérebro (BDNF) e marcadores de assinatura biológica para DA. Não foi evidenciada diferença entre os três diferentes grupos em relação ao selênio e a SELENOP da mesma forma que não houve influência do genótipo APOE ε4 nas concentrações de selênio e SELENOP, porém houve uma tendência de menores concentrações de selênio plasmático nos carreadores do alelo APOE ε4. Também houve uma tendência a uma menor pontuação nos testes MMSE e CAMCOG em indivíduos com menores concentrações plasmáticas de selênio. Não se evidenciou que o estado nutricional dos indivíduos em relação ao selênio influencie as concentrações de marcadores para assinatura biológica para DA e de citocinas inflamatórias, com exceção da IL-10 que apresentou correlação positiva com SELENOP plasmática. A partir desses resultados, conclui-se que o estado nutricional dos indivíduos relativo ao selênio parece não ter influencia significativa em aspectos do CCL e DA e que sua distribuição não é alterada pelo genótipo APOE ε4

Alzheimer's disease (AD) is the main form of dementia and one of the major challenges in the healthcare system of the 21st century. Mild Cognitive Impairment (MCI) is a stage that precedes AD and shares common metabolic pathways. The pathophysiology of AD is characterized by extensive neuronal death, presence of neuritic plaques and neurofibrillary tangles, respectively related to the accumulation of amyloid beta peptide (Aß) in brain tissues and changes in the cytoskeleton that originate from hyperphosphorylation of the Tau protein in neurons. Some lines of evidence support the hypothesis that oxidative, nitrosative stress and inflammation play an important role in the pathogenesis of both AD and MCI. Selenium, an essential mineral to humans, is incorporated into the active site of 25 selenoproteins, of which at least one third has an antioxidant role, in addition to its potential in modulating the inflammatory system. Therefore, the appropriate nutritional status related to selenium seems to exert a neuroprotective effect, reducing the risk for MCI and AD and decreasing the progression of these diseases. Selenium is delivered to the brain by the interaction of selenoprotein P (SELENOP) with the ApoE2 receptor (ApoER2). Apolipoprotein E (ApoE) also interacts with ApoER2 in lipid metabolism. Thus, it can be speculated that individuals that carry apolipoprotein E ε4 gene (APOE ε4), the main genetic polymorphism that increases the risk of AD, may have impaired selenium delivery to the brain since ApoER2 receptors of the APOE ε4 carriers are sequestered to intracellular compartments, being less expressed in the plasma membrane decreasing its interaction with SELENOP. This study aimed to assess whether the distribution of selenium in the plasma and CSF of subjects with MCI and AD is affected by the APOE ε4 allele, evaluate whether the nutritional status of selenium affects biological signature markers for AD (amyloid beta peptide, tau protein and phosphorylated tau protein) and to asses the concentrations of inflammatory cytokines. For this purpose, plasma and cerebrospinal fluid (CSF) samples were selected from the biological material bank of the Institute of Psychiatry of FMUSP, with 14 subjects from the MCI group, 28 from the DA group and 28 from control subjects, both genders, aged over 60 years and São Paulo residents. The following markers were evaluated: selenium concentrations in plasma and CSF, SELENOP concentrations in plasma and CSF, inflammatory cytokines, brain-derived neurotrophic factor (BDNF) and biological signature for AD. There was no difference between the three different groups in relation to selenium and SELENOP; in addition, there was no influence of the APOE ε4 genotype on selenium and SELENOP concentrations, but there was a tendency towards lower plasma selenium concentrations in the APOE ε4 carriers. There was also a tendency for lower scores on the MMSE and CAMCOG tests in subjects with lower plasma selenium concentrations. It was not shown that selenium nutritional status influences the concentrations of biological signature for AD and inflammatory cytokines, with the exception of IL-10 which showed a positive correlation with plasma SELENOP. From these results, we concluded that selenium nutritional status does not seem to have a significant influence in aspects of MCI and DA and that its distribution is not altered by the APOE genotype ε4

Correlations Between Single Nucleotide Polymorphisms, Cognitive Dysfunction, and Postmortem Brain Pathology in Alzheimer's Disease Among Han Chinese / 神经科学通报·英文版

In this study, the distribution of five Alzheimer's disease (AD)-related single nucleotide polymorphisms (SNPs) in the Han population was examined in combination with the evaluation of clinical cognition and brain pathological analysis. The associations among SNPs, clinical daily cognitive states, and postmortem neuropathological changes were analyzed in 110 human brains from the Chinese Academy of Medical Sciences/Peking Union Medical College (CAMS/PUMC) Human Brain Bank. APOE ε4 (OR = 4.482, P = 0.004), the RS2305421 GG genotype (adjusted OR = 4.397, P = 0.015), and the RS10498633 GT genotype (adjusted OR = 2.375, P = 0.028) were associated with a higher score on the ABC (Aβ plaque score, Braak NFT stage, and CERAD neuritic plaque score) dementia scale. These results advance our understanding of the pathogenesis of AD, the relationship between pathological diagnosis and clinical diagnosis, and the SNPs in the Han population for future research.

The Effect of Clinical Characteristics and Subtypes on Amyloid Positivity in Patients with Amnestic Mild Cognitive Impairment

BACKGROUND AND PURPOSE: Mild cognitive impairment (MCI) is a prodromal stage of dementia. Amyloid deposits in positron-emission tomography (PET) imaging of MCI patients imply a higher risk for advancing to dementia, with rates of 10%–15% yearly. The purpose of this study was to investigate the clinical characteristics of subgroups of amnestic MCI (aMCI) that may have a higher impact on amyloid positivity.METHODS: We recruited 136 aMCI patients. All patients underwent a 20-minute F-18 florbetaben or flutemetamol PET scan. We classified amyloid PET images as positive or negative according to a semi-quantitative method. We evaluated the amyloid positivity of subgroups of aMCI (early vs. late type, single vs. multiple amnestic type, verbal vs. verbal, and visual amnestic type), and compared baseline clinical characteristics including key risk factors, apolipoprotein E4 (apoE4) genotype, and neuropsychological assessments with amyloid positivity in aMCI.RESULTS: The amyloid positivity in total aMCI was 41%. The positivity rate according to subgroup of aMCI were as follow: Late aMCI (49%) vs. early aMCI (33%) (p=0.13), multiple aMCI (40%) vs. single aMCI (38%) (p=0.51), and verbal and visual aMCI (59%) vs. verbal aMCI (35%) (p=0.01), respectively. The mean age and the frequency of apoE4 allele of the amyloid-positive group was higher than that of the amyloid-negative group in aMCI (p< 0.01).CONCLUSIONS: We found that the amyloid positivity was related to patterns of clinical subtypes, characteristics, and risk factors in patients with aMCI.

Apolipoprotein E polymorphism and functional disability in Brazilian elders: the Bambuí Health and Aging Study / Polimorfismo da apolipoproteína E e incapacidade funcional em idosos brasileiros: Projeto Bambuí / Polimorfismo de la apolipoproteína E e incapacidad funcional en los ancianos brasileños: Proyecto Bambuí

Abstract Numerous studies have associated the apolipoprotein E (apoE) ε4 allele with worse health status, but few have assessed the existence of genotype-dependent variations in functional performance. Among participants in the Bambuí Health and Aging Study, Minas Gerais State, Brazil, 1,408 elderly underwent apoE genotyping. Functionality was assessed with a questionnaire, and individuals were classified as dependent in basic activities of daily living (BADLs), instrumental activities of daily living (IADLs), and mobility. The association between apoE genotype and functional status was assessed by logistic regression, taking confounding factors into account. Presence of ε4 allele was associated with lower odds of mobility deficit (OR = 0.65; 95%CI: 0.47-0.92) in the adjusted analysis. There were no significant differences in relation to presence of dependency in BADLs and IADLs. The reasons are not entirely understood, but they may involve the role of ε4 allele as a "thrifty gene" in a sample exposed to high risk of infectious and nutritional diseases in the past.

Resumo Inúmeros estudos têm associado o alelo ε4 da apolipoproteína E (apoE) com pior condição de saúde, mas poucos avaliaram a existência de variações genótipo-dependentes no desempenho funcional. Entre os participantes da coorte de Bambuí, Minas Gerais, Brasil, 1.408 idosos foram submetidos à genotipagem da apoE. A funcionalidade foi avaliada por questionário, sendo os indivíduos classificados em dependentes para atividades básicas da vida diária (ABVDs), atividades instrumentais da vida diária (AIVDs) e mobilidade. A associação entre o genótipo da apoE e o estado funcional foi avaliada pela regressão logística, considerando variáveis de confusão. A presença do alelo ε4 foi associada a uma menor chance de déficit na mobilidade (OR = 0,65; IC95%: 0,47-0,92), na análise ajustada. Não houve diferenças significativas em relação à presença de incapacidades em ABVDs e AIVDs. Os motivos não estão completamente compreendidos, mas podem envolver o seu papel como um "thrifty gene" em uma amostra exposta a um risco elevado de doenças infecciosas e nutricionais no passado.

Resumen Innumerables estudios han asociado el alelo ε4 de la apolipoproteína E (apoE) con una peor condición de salud, pero pocos evaluaron la existencia de variaciones genotipo-dependientes en el desempeño funcional. Entre los participantes de la cohorte de Bambuí, Minas Gerais, Brasil, 1.408 ancianos fueron sometidos a una determinación del genotipo de la apoE. La funcionalidad fue evaluada por cuestionario, siendo los individuos clasificados en: dependientes para actividades básicas de la vida diaria (ABVDs), actividades instrumentales de la vida diaria (AIVDs) y movilidad. La asociación entre el genotipo de la apoE y el estado funcional fue evaluada por regresión logística, considerando variables de confusión. La presencia del alelo ε4 fue asociada a una menor probabilidad de déficit en la movilidad (OR = 0,65; IC95%: 0,47-0,92) en el análisis ajustado. No hubo diferencias significativas en relación con la presencia de incapacidades en ABVDs y AIVDs. Los motivos no están completamente claros, pero pueden están involucrados por su papel como un "thrifty gene" en una muestra expuesta a un riesgo elevado de enfermedades infecciosas y nutricionales en el pasado.

Independent and Interactive Influences of the APOE Genotype and Beta-Amyloid Burden on Cognitive Function in Mild Cognitive Impairment

This study aimed to investigate the independent and interactive influences of apolipoprotein E (APOE) epsilon4 and beta-amyloid (Abeta) on multiple cognitive domains in a large group of cognitively normal (CN) individuals and patients with mild cognitive impairment (MCI) and Alzheimer's disease (AD). Participants were included if clinical and cognitive assessments, amyloid imaging, and APOE genotype were all available from the Alzheimer's Disease Neuroimaging Initiative database (CN = 324, MCI = 502, AD = 182). Individuals with one or two copies of epsilon4 were designated as APOE epsilon4 carriers (epsilon4+); individuals with no epsilon4 were designated as APOE epsilon4 non-carriers (epsilon4-). Based on mean florbetapir standard uptake value ratios, participants were classified as Abeta burden-positive (Abeta+) or Abeta burden-negative (Abeta-). In MCI, APOE epsilon4 effects were predominantly observed on frontal executive function, with epsilon4+ participants exhibiting poorer performances; Abeta positivity had no influence on this effect. Abeta effects were observed on global cognition, memory, and visuospatial ability, with Abeta+ participants exhibiting poorer performances. Measures of frontal executive function were not influenced by Abeta. Interactive effects of APOE epsilon4+ and Abeta were observed on global cognition and verbal recognition memory. Abeta, not APOE epsilon4+, influenced clinical severity and functional status. The influences of APOE epsilon4+ and Abeta on cognitive function were minimal in CN and AD. In conclusion, we provide further evidence of both independent and interactive influences of APOE epsilon4+ and Abeta on cognitive function in MCI, with APOE epsilon4+ and Abeta showing dissociable effects on executive and non-executive functions, respectively.

ApoE4 increases glycogen synthase kinase 3β expression and Tau phosphorylation in U87 cells / 南方医科大学学报

<p><b>OBJECTIVE</b>To explore the relations among apolipoprotein E4, Tau protein and glycogen synthase kinase 3β (GSK-3β).</p><p><b>METHODS</b>U87 cells were transfected with pIRES-EGFP (control) or the recombinant plasmids ApoE4/pIRES-EGFP or ApoE3/pIRES-EGFP, and the expression levels of p-Tau/Tau and GSK-3β in the cells were examined with Western blotting. To further confirm the effect of ApoE on GSK-3β and p-Tau expressions, a short interfering RNA (siRNA) targeting ApoE (ApoE-siRNA) was transfected into U87 cells via Lipofectamine 2000 and the protein expressions were examined 24 h later.</p><p><b>RESULTS</b>Compared with those in the control group, the expressions levels of both GSK-3β and p-Tau/Tau increased significantly in the cells transfected with ApoE4 and ApoE3 plasmids (P<0.01), and the ApoE4 plasmid produced a more potent effect than the ApoE3 plasmid on the protein expressions (P<0.01). ApoE knockdown resulted in significantly reduced expressions of GSK-3β (P<0.001) and p-Tau (P<0.01) in the cells.</p><p><b>CONCLUSION</b>ApoE4 can enhance Tau phosphorylation though upregulating GSK-3β, which sheds light on a new role of ApoE4 in Alzheimer's disease.</p>

The Clinical Usefulness of Beta-Amyloid Positron Emission Tomography Imaging in the Elderly Patients: Case Series & Brief Review

The aim was to evaluate the diagnostic utility of beta-amyloid positron emission tomography (PET) in elderly patients with cognitive impairment in the clinical setting. Five subjects underwent beta-amyloid PET imaging to explore the cerebral beta-amyloid deposition. The two male patients with minor neurocognitive disorder due to Alzheimer's disease, who displayed similar degree of cognitive impairment and medial temporal atrophy but different in apolipoprotein E4 status, both showed negative for beta-amyloid PET. On the other hand, a female major neurocognitive disorder due to probable Alzheimer's disease patient was tested positive for beta-amyloid PET, with increased beta-amyloid density in frontal and parietal lobes. Beta-amyloid PET was also used for the differential diagnosis of neurocognitive disorder from other psychiatric disorders in two elderly patients. The results were negative but assisted the diagnositic confirmation. A female patient was determined to be a case of late-onset schizophrenia and a male patient was determined as delirium due to minor traumatic brain injury, persistent. Beta-amyloid PET imaging was able to demonstrate cerebral beta-amyloid deposition in major neurocognitive disorder due to probable Alzheimer's disease in visual scale. However, further studies are needed for its clinical utility in the minor neurocognitive disorders. Moreover, beta-amyloid PET imaging may provide additional information in diagnosing primary psychiatric disorders with new onset in the old age.

Distinct Clinical Characteristics Depending on Cerebral Amyloid Positivity in Patients with Alzheimer Disease Dementia

OBJECTIVE: The present study investigated the clinical characteristics of Alzheimer's disease (AD) dementia with low brain amyloid-beta (Aβ-AD) burden comparing with AD dementia with high amyloid-beta burden (Aβ+AD). We also developed a prediction model for the amyloid positivity on ¹¹C-labelled Pittsburgh Compound B (PiB) positron emission tomography (PET) with distinct clinical variables in AD dementia patients. METHODS: Fifty-nine clinically defined AD dementia individuals, who participated in the Korean Brain Aging Study for Early diagnosis and prediction of AD (KBASE) study, were included. All the subjects received comprehensive clinical evaluations and PiB-PET. Based on cerebral PiB retention, all subjects were divided into Aβ+AD (n=47) and Aβ-AD (n=12) subgroups. To develop a prediction model for amyloid positivity, stepwise multiple logistic regression analysis was conducted. RESULTS: When compared to Aβ+AD, Aβ-AD showed older age, later age-at-onset, and lower education. In regard of risk factors for dementia, Aβ-AD had higher frequency of hypertension and diabetes mellitus as well as lower frequency of apolipoprotein E (APOE) ε4 allele. Although there was no between group difference in Clinical Dementia Rating (CDR) or CDR sum-of-boxes scores, mini-mental state examination and constructional recall scores were higher for Aβ-AD than Aβ+AD. The final amyloid positivity prediction model included APOE4 genotype, hypertension, and diabetes mellitus. CONCLUSION: The findings from this study indicated that clinically diagnosed AD dementia may have high possibility of not being pathological AD if they have older age and higher vascular risks, and did not have APOE4 genotype.

Apolipoprotein E4: A Risk Factor for Successful Cognitive Aging

Apolipoprotein E is a plasma protein that has an important role in transport and metabolism of lipids in serum as well as central nervous system. Among the 3 common alleles, the ε2 allele has the most stable structure followed by ε3 and ε4 in order. There is evidence for a deleterious role of ε4 allele by atherosclerosis and amyloid beta accumulation in brain and body. The presence and gene dose of ε4 allele are risk factors for late-onset Alzheimer's disease. Apolipoprotein E ε4 may have a role in the pathology of amyloid beta and tau and it has a strong relationship with the early onset of late-onset Alzheimer's disease. However, early-onset Alzheimer's disease has a weaker relationship with ε4 allele of apolipoprotein E.

Descripción genotípica y fenotípica de la enfermedad de Alzheimer tardía y familiar precoz: revisión / Genotypic and phenotypic description of late-onset Alzheimer's disease and early onset familial Alzheimer's: Review / Descrição genotípica e fenotípica da doença de Alzheimer tardia e familiar precoce: revisão

La demencia es la pérdida de varias áreas del funcionamiento cognitivo respecto al nivel premórbido, con deterioro significativo en la funcionalidad. La más común es ocasionada por la enfermedad de Alzheimer, que se define como un trastorno neurodegenerativo que produce una alteración progresiva de la memoria y de otras habilidades mentales, por una pérdida de volumen en los lóbulos temporales, en especial en las áreas mediales como el hipocampo y la corteza entorrinal. Menos del 5% de los pacientes con esta enfermedad presenta formas hereditarias que pueden tener un inicio precoz (antes de los 65 años) o tardío (después de dicha edad). La EA precoz presenta un patrón de herencia autosómico dominante y puede ser causado por mutaciones en el gen de la proteína precursora de amiloide, en presenilina-1 o presenilina-2. Los casos de EA tardía, están influenciados por una genética compleja, con múltiples factores de susceptibilidad y el alelo ApoE4 es el principal y más reconocido. La EA es una enfermedad heterogénea tanto en su genotipo como en su fenotipo que varían en cuanto a intensidad y tipo de síntomas, edad de inicio y severidad de la demencia, de acuerdo con las mutaciones que el paciente presenta y su interacción con factores ambientales.

Dementia is known as the loss of multiple areas of cognitive function with respect to a premorbid condition, involving a significant deterioration in functionality. The most common subtype is Alzheimer's disease, which is defined as a neurodegenerative disorder that causes a progressive deterioration in memory and other mental capacities due to volume loss in temporal lobes, especially in mesial aspects, such as the hippocampus and the entorhinal cortex. Approximately 5% of patients affected by this disease have a hereditary form, with an early onset (before 65 years) or a late onset (after 65 years). Early onset Alzheimer's disease has a genetic autosomal dominant inheritance pattern, which can be caused by mutations in the gene encoding for the amyloid precursor protein, presenilin-1, or presenilin-2. In the cases of late onset Alzheimer's disease, there is a complex genetic influence, with multiple susceptibility factors, where the ApoE4 allele is the main and most recognized factor. Alzheimer's disease is a heterogeneous dementia, both in genotype and phenotype, varying in intensity and symptoms, age of onset, and severity of the disease, depending on the different mutations that a patient may have and the interactions with environmental factors.

A demência é a perda de várias áreas do funcionamento cognitivo com respeito ao nível pré-mórbido, com deterioro significativo na funcionalidade. A mais comum é ocasionada pela doença de Alzheimer, que se define como um transtorno neurodegenerativo que produz uma alteração progressiva da memória e de outras habilidades mentais, por uma perda de volume nos lóbulos temporais, em especial nas áreas mediais como o hipocampo e o córtex entorrinal. Menos de 5% dos pacientes com esta doença apresenta formas hereditárias que podem ter um início precoce (antes dos 65 anos) ou tardio (depois de dita idade). A D.A. precoce apresenta um padrão de herança autossômico dominante e pode ser causado por mutações no gene da proteína precursora de amiloide, em presenilina-1 ou presenilina-2. Os casos de D.A. tardia, estão influenciados por uma genética complexa, com múltiplos fatores de susceptibilidade e o alelo ApoE4 é o principal e mais reconhecido. A D.A. é uma doença heterogénea tanto em seu genótipo como em seu fenótipo que variam em quanto a intensidade e tipo de sintomas, idade de inicio e severidade da demência, de acordo com as mutações que o paciente apresenta e sua interação com fatores ambientais.

Effects of beta-amyloid and apolipoprotein E4 on hippocampal choline acetyl transferase in rats / 中华病理学杂志

<p><b>OBJECTIVE</b>To investigate the effects of beta-amyloid (Aβ) and apolipoprotein E4(apoE4) on choline acetyl transferase (ChAT) in hippocampus and to explore possible the synergistic effect of both Aβ and apoE4.</p><p><b>METHODS</b>Male Wistar rats were divided into four groups: control group, Aβ group, apoE4 group and Aβ + apoE4 group. Rats in different group received injection of normal saline, Aβ1-40, apoE4 and Aβ1-40 + apoE4, respectively, into bilateral hippocampus CA1 regions under the control of a brain stereotaxic apparatus. The learning-memory ability with the escape latency and the times of passing platform and the expression of ChAT in hippocampus CA1 regions were documented.</p><p><b>RESULTS</b>The escape latency at fifth day and the times of passing platform and ChAT mRNA PU values were obtained for the control group (10.75 s ± 2.44 s, 4.13 ± 0.64, and 28.90 ± 4.43), apoE4 group (23.88 s ± 4.32 s, 2.38 ± 0.52, and 20.85 ± 3.98), Aβ group (43.50 s ± 9.78 s, 1.38 ± 0.52, and 16.96 ± 2.53), and Aβ + apoE4 group (70.63 s ± 10.04 s, 0.75 ± 0.71, and 13.01 ± 2.21). Through 5 days of training all animals acquired learning-memory ability with the gradually shortened escape latency, although injection of Aβ1-40 and apoE4 all induced learning-memory damage, due to a significantly prolonged the escape latency at fifth day (P < 0.01) and markedly decreased the times of passing platform (P < 0.01) in both Aβ and apoE4 group than in control group. An interaction between Aβ and apoE4 also was observed, with further prolonged escape latency(P < 0.01). ChAT mRNA PU values were significantly lower in the Aβ group and apoE4 group than in the control group (P < 0.01). Aβ and apoE4 demonstrated interaction in lowering ChAT mRNA level(P < 0.05).</p><p><b>CONCLUSIONS</b>Both Aβ and apoE4 induce an injury to hippocampal cholinergic system and its learning-memory ability, in which Aβ and apoE4 have a synergistic effect in the initiation of such injury.</p>

Apolipoprotein E4 Genotype and Depressive Symptoms as Risk Factors for Dementia in an Older Korean Population

OBJECTIVE: Growing evidence suggests the separate associations of apolipoprotein E e4 allele (apo E4) and depression with incident dementia. This study investigated the separate and combined effects of apo E4 and depression on the incidence of dementia in both men and women. METHODS: Of 625 elderly without dementia at baseline, 518 (83%) were followed over a 2.4-year period and were assessed clinically for incident dementia. The apo E polymorphism was ascertained, and depression was identified using the Korean version of the Geriatric Depression Scale (KGDS). Covariates included age, gender, education, disability, alcohol history, physical activity, and vascular risk factors. RESULTS: The incidence of dementia was significantly higher in elderly Koreans with both apo E4 and depression compared to those without both factors [adjusted odds ratio (95% CI)=5.85 (1.77-19.38)]. This interaction was significant in men (p=0.049), but not in women (p=0.354). CONCLUSION: Depressed elderly people are at great risk for incident dementia in the presence of apo E4. Potential gender differences require further evaluation.

Relationship between apolipoprotein E polymorphism and cognitive function in patients with primary hypertension / 生物医学工程学杂志

To explore the relationship between apolipoprotein E polymorphism and cognitive function in primary hypertension patients, we collected 200 Chinese primary hypertensive patients. Blood pressure (BP), heart rate (HR), height, body weight, waistline, hip circumference were measured. The Mini Mental State Examination (MMSE) was applied to test the cognitive function and compute score. Full-automatic bio-chemistry analyzer was used to determine total cholesterol (TC) and triglyeride (TG) and fasting glucose. The polymerase chain reaction-restriction fragment length polymorphism (PCR-RELP) was used for the analysis of the apolipoprotein E polymorphism. We found that in primary hypertension patients, the genotype frequency of epsilon3/4 and epsilon4/4 were significantly higher in the cognitive impairment group than that in the cognitive normal group. The allele frequency of e4 is obviously higher in the cognitive impairment group than that in the cognitive normal group. Age and epsilon4/4 genetype were positively correlated with hypertensive-cognitive impairment, while cultural level was negtively correlated with it. ApoEepsilon4 allele and age might be risk factors for the cognitive impairment in hypertensive patients. The epsilon4 homozygote (epsilon4/4) might be an important influencing factor for the progression of cognitive impairment.

Interaction of Apolipoprotein E epsilon4 and Education on Cognitive Decline in Korean Elders

OBJECTIVES: This study aimed to test potential modifying effects of education on the association between apolipoprotein E epsilon4 (Apo E4) and cognitive decline. METHODS: A community cohort(N=683) aged 65 or over completed the Korean version of Mini-Mental State Examination(MMSE-K) at baseline and two years later(1999-2001). Apo E polymorphisms were genotyped, and classified into that with or without Apo E4. Educational levels were categorized into people with or without education. Covariates included demographic(age, gender), life style(smoking, alcohol drinking), clinical (depression, sleep disorder, vascular risk factors) characteristics. RESULTS: The association between Apo E4 and cognitive decline was significant only in the old persons with no education. The interaction term between education and Apo E4 on cognitive decline was significant (p=0.040). CONCLUSION: Elders with no education might be more vulnerable to the impact of Apo E4 on cognitive decline, which suggests gene-environment interaction.

Relationship between apolipoprotein e4 allele and emergence agitation in patients undergoing general anesthesia / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the relationship between apolipoprotein e4 allele and emergence agitation (EA) in patients undergoing general anesthesia.</p><p><b>METHODS</b>A nested cohort study was conducted in elderly patients (over 60 years old) scheduled for major abdominal surgery requiring general anesthesia. A structured interview was conducted in PACU to determine EA, defined using the Sedation-Agitation Scale (SAS). Blood samples were obtained for measurement of the apolipoprotein genotypes.</p><p><b>RESULTS</b>Of the 196 patients studied, 22.4% developed EA. Thirty-eight patients (19.4%) had the apolipoprotein e4 allele. The presence of the e4 allele and low level of education were both associated with an increased risk of EA (36.9% vs15.8%, P=0.005; 30% vs 14.3%, P=0.01). After adjustment for covariates, the patients with the copy of e4 allele were shown to have a greater likeliness of an increased risk of EA (odds ratio: 4.32; 95% CI: 1.75-10.05) than those without the e4 allele.</p><p><b>CONCLUSION</b>Apolipoprotein e4 carrier status is associated with an increased risk for EA.</p>

Alzheimer's disease: epidemiology, genetics, and beyond / 神经科学通报·英文版

Alzheimer's disease (AD) is an increasing epidemic threatening public health. Both men and women are susceptible to the disease although women are at a slightly higher risk. The prevalence of AD rises exponentially in elderly people from 1% at age of 65 to approximately 40%-50% by the age of 95. While the cause of the disease has not been fully understood, genetics plays a role in the onset of the disease. Mutations in three genes (APP, PSEN1, and PSEN2) have been found to cause AD and APOE4 allele increases the risk of the disease. As human genomic research progresses, more genes have been identified and linked with AD. Genetic screening tests for persons at high risk of AD are currently available and may help them as well as their families better prepare for a later life with AD.