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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.
Subject(s)
Apolipoprotein E4 , Alzheimer Disease , Venezuela , Dementia , Cognitive DysfunctionABSTRACT
Abstract Alzheimer's disease is a neurodegenerative condition that causes changes in memory and cognition, in addition to behavioral disorders, and most commonly affects the elderly. Several studies in the literature have presented therapeutic measures in an attempt to interfere with the pathogenic mechanisms of the disease and to mitigate its clinical manifestations. Some factors, such as excitotoxicity, cholinergic dysfunctions, oxidative stress, tau protein hyperphosphorylation, changes in amyloid-beta peptide metabolism, herpes viruses, apolipoprotein E, glycogen synthase kinase 3, insulin resistance, and the endocannabinoid system seem to be related to pathophysiology of Alzheimer's disease. Given this, a literature review was carried out to address the molecular mechanisms associated with the pathophysiological hypotheses previously mentioned, aiming to better understanding their underlying causes and contributing to possible pharmacological strategies about treatment of the disease.
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RESUMO A doença neurodegenerativa mais comum no mundo é a doença de Alzheimer (DA), e 10% dos casos apresentam sintomas antes dos 65 anos, quase todos com associação genética, com hereditariedade autossômica dominante e penetrância entre 92 a 100% dos portadores. Na presente revisão, realizamos uma busca sobre as variantes genéticas associadas à doença de Alzheimer de início precoce (DAIP), enfatizando as características associadas mais importantes e as principais mutações já descritas. Os genes mais comumente relacionados com o surgimento da DAIP são APP, PSEN1, PSEN2 e MAPT, e mutações nestes afetam o metabolismo e a estrutura destas proteínas, resultando em acúmulos de peptídeo Aβ que causam inflamação e toxicidade no cérebro, levando à ativação da micróglia e promovendo a liberação de fatores neurotóxicos e pró-inflamatórios que aceleram a neurodegeneração. O gene PSEN1 é responsável por 70% das mutações conhecidas da DAIP, sendo a L166P associada à idade de ocorrência da doença abaixo dos 30 anos. Mutações em APP levam à agregação da proteína em placas neurodegenerativas. Todas as mutações descritas para MAPT estão associadas a um aumento dos emaranhados neurofibrilares. O polimorfismo E4 da Apolipoproteína E (APOE) influencia o aumento no risco de DAIP elevando as chances em três vezes para portadores heterozigotos e entre oito a dez vezes para os homozigotos. Apenas 5% das mutações associadas à DAIP são conhecidas, e novos estudos apresentam outros genes candidatos, bem como a importância de alterações epigenéticas na gênese desta doença.
SUMMARY The most common neurodegenerative disease in the world is Alzheimer's Disease (AD). Ten percent of Alzheimer patients experience symptoms before the age of 65, and almost all of them present genetic features of autosomal dominant inheritance nature, and penetrance of 92 to 100%. In the present review, we searched for genetic variants associated with early onset Alzheimer's disease (EOAD), emphasizing the most important characteristics and the main mutations. The genes most commonly related to the onset of EOAD are APP, PSEN1, PSEN2 and MAPT, whose mutations affect the metabolism and structure of these proteins. This process results in accumulations of Aβ peptide that leads to activation of the microglia and release of neurotoxic and pro-inflammatory factors that accelerate neurodegeneration. The PSEN1 gene is responsible for 70% of the known mutations in EOAD, while L166P is associated with below 30 years as the starting age of occurrence. APP mutations lead to protein aggregation in neurodegenerative plaques. All of the mutations described for MAPT are associated with an increase in neurofibrillary tangles. The E4 polymorphism of Apolipoprotein E (APOE) influences an increased risk of EOAD increasing up to three times the chances for heterozygous, and between eight and ten times for homozygotes carriers. Only 5% of the mutations associated with EOAD are known; new studies will show other candidate genes, as well as the importance of epigenetic factors changes in the etio-pathogenesis of this disease.
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Objective@#To investigate the relationship between apolipoprotein E (APOE) gene polymorphism and cerebral infraction (CI) in Chinese type 2 diabetes mellitus (T2DM) patients.@*Methods@#This study included 245 samples of T2DM patients without cerebral infraction (CON group) (Male/Female, 128/117) and 270 samples of T2DM patients with cerebral infraction (CI group)(Male/Female, 145/125) from the department of endocrinology and neurology utilizing real-time fluorescence quantitative PCR technique. The t test and χ2 test were used to compare the differences between the two groups.@*Results@#Patients with a history of hypertension in the CI group (84.12%) were significantly higher than those in the CON group (70.42%) (χ2=15.91, P<0.05).The systolic blood pressure (142.78±20.52)mmHg of the CI group was significantly higher than that of the CON group (133.89±18.58)mmHg (t=-5.16, P<0.05).Compared with CON group, the frequency of genotypes of ε2/ε3 and ε3/ε4 in CI group was significantly higher, while the frequency of ε3/ε3 genotype was significantly lower (χ2=11.48, P<0.05); the allele frequency of APOE ε4 was higher while ε3 was lower in CI group than that in CON group (χ2=7.00, P<0.05). Logistic regression analysis showed that hypertension history (OR=1.95, P<0.05), high systolic blood pressure (OR=1.02, P<0.05), APOE genotypes of ε2/ε3 (OR=2.08, P<0.05) and ε3/ε4 (OR=1.85, P<0.05) were independent risk factors for cerebral infarction in T2DM patients.@*Conclusion@#The polymorphism of APOE gene may be related to cerebral infraction in Chinese T2DM patients.
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Objective To compare the neuropsychological features and other clinical and imaging characteristics among patients with typical Alzheimer's disease (TAD),frontal variant Alzheimer's disease (fvAD) and behavioral variant frontotemporal dementia (bvFTD).Methods Neuropsychological scales were used to evaluate the cognitive function and neuropsychiatric symptoms of nine patients with fvAD,30 patients with bvFTD and 32 patients with typical AD (TAD).The apolipoprotein E (ApoE) ε4 allele and brain imaging techniques,including the magnetic resonance imaging (MRI),11 C-Pittsburgh compound B positron emission tomography (PIB-PET),and 18F-deoxyglucose positron emission tomography (FDG-PET),were used for the differential diagnosis of fvAD and bvFTD.Results There were no significant differences in general cognitive function or daily activity in patients among the three groups.However,the cognitive subscale scores of Montreal Cognitive Assessment (MoCA) scale,including visual acuity and executive function,delayed recall,and orientation,were significantly different among the groups (Z =7.891,P =0.035;Z =7.412,P =0.031;Z=6.437,P=0.043,respectively).The clock drawing test (CDT) score of TAD group was higher than that in the bvFTD and fvAD groups (Z=8.673,P=0.020),while the neuropsychological questionnaire (NPI) scores of the bvFTD and fvAD groups were higher than those of the TAD group (Z=7.577,P =0.023).Meanwhile,the incidences of agitation,disinhibition and abnormal behavior of NPI in the bvFTD and fvAD groups were higher than those in the TAD group (x2 =11.139,P =0.004;x2 =6.481,P =0.039;x2 =6.812,P =0.033,respectively).The frequencies of the ApoE ε4 allele were 44.4％ in the fvAD group and 33.3％ in the bvFTD group,which were not significant different from that in the TAD group (40.6％).Furthermore,patients in the fvAD group were associated with decreased regional cerebral glucose metabolism and amyloid deposition in the temporalparietal cortex evaluated by FDG-PET and PIP-PET.Conclusions Neuropsychological evaluation is valuable for the differential diagnosis of TAD,fvAD and bvFTD.The frequencies of the ApoEε4 allele are similar among the three groups.FDG-PET and PIB-PET imaging plays an important role in the diagnosis of variant types of Alzheimer's disease.
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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.
Subject(s)
Humans , Male , Female , Aged , Polymorphism, Genetic/genetics , Activities of Daily Living , Mobility Limitation , Apolipoprotein E4/genetics , Brazil , Cohort Studies , Disability Evaluation , GenotypeABSTRACT
Objective To investigate the effects of nicergoline on expressions of 5-hydroxytryptamine 1A receptor (5-HT1AR), D2 dopamine receptor (D2DR),α2A adrenaline receptor (α2AAR) in the hippocampal CA1 region and the serum level of apolipoprotein E4 (ApoE4) in a rat model of vascular depression (VD) . Methods Forty-eight male Sprague-Daw ley rats w ere randomly al ocated into a normal control group, a model group, fluoxetine group, a low-dose nicergoline group, a medium-dose nicergoline group, and a nicergoline high-dose group ( n=8 in each group). A rat model of VD w as induced by the ligation of bilateral common carotid arteries combined w ith chronic unpredictable mild stress (CUMS) plus single housing. The rats did not conduct CUMS or single housing in the normal control group, and the rats in the model group conducted CUMS and single housing. The rats in the fluoxetine group w ere given fluoxetine 1.3 mg/(kg· d) for gastric lavage for 3 w eeks at the beginning of CUMS and single housing. The rats in the low -, medium-and high-dose nicergoline groups w ere given nicergoline 0.9, 1.9 and 3.8 mg/(kg· d), respectively for gastric lavage for 3 w eeks at the beginning of CUMS and single housing. The normal control group and the model group w ere given equal volume of distil ed w ater for gastric lavage, once a day for 3 w eeks. Depression-like behavior w as evaluated using sucrose solution consumption and open-field test. Immunohistochemical staining and Western blot were used to detect the expressions of 5-HT1AR, D2DR, andα2AAR in the hippocampal CA1 region. Enzyme linked immunosorbent assay w as used to detect serum ApoE4 level. Results Before CUMS, the scores of horizontal and vertical movement and sucrose solution consumption in the model group, the fluoxetine group and each nicergoline group w ere decreased significantly compared w ith the normal control group (al P<0.01);w hile at 21 days after CUMS, those in the fluoxetine group and the nicergoline medium-and high-dose groups w ere significantly higher than those in the model group (al P<0.05). There w ere no significant differences betw een the fluoxetine group and each nicergoline group. The expression levels of 5-HT1A R, D2DR, α2A AR, and the serum ApoE4 in the model group, the fluoxetine group, and each nicergoline group w ere significantly higher than those in the normal control group. Those of the fluoxetine group and the nicergoline medium -and high-dose groups were significantly lower than the model group (al P<0.01), while there were no significant differences betw een the fluoxetine group and each nicergoline group. Conclusions Nicergoline can improve the depression-like behavior in VD rats. Its mechanism may be associated w ith the dow nregulation of 5-HT1AR, D2DR, α2AAR expressions and serum ApoE4 level.
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AIM To study the effects of A? 25～35 and Apo E4 on neuronal intracellular free Ca 2+ ([Ca 2+ ] i). METHODS Hippocampal and cortical neurons suspension of newborn(0～3 days) SD rats was produced. After incubated with fura 2/AM,the neurons suspension was divided into four groups: control, A? 25～35 , Apo E4, A? 25～35 +Apo E4. Each groups [Ca 2+ ] i was measured using a RF 5000 dual wavelength spectrofluorometer after incubated with double distilled water, A? 25～35 , Apo E4, A? 25～35 +Apo E4 for 3 min, respectively. The neurons outocorrelation function(ACF) of the scattering light intersity was analyzed by the microscope quasi elastic light scattering(MQLS) technique The frequency shift line width by ACF. The ? can sympolize the cell menbrane flilidity. RESULTS Both A? 25～35 and Apo E4 could significantly enhance hippocampal and cortical neurons rest [Ca 2+ ] i, furthermore, the effect of 5 ?mol?L -1 A? 25～35 was higher than the effect of 1 ?mol?L -1 A? 25～35 ( P