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Synaptic dysfunction is an early feature in Alzheimer's disease (AD) pathogenesis and a major morphological correlate of memory deficits. Given the main synaptic location of N-methyl-D-aspartate receptors (NMDARs), their dysregulation has been implicated in these pathological effects. Here, to detect possible alterations in the expression and synaptic localisation of the GluN1 subunit in the brain of amyloidogenic APP/PS1 mice, we employed histoblot and SDS-digested freeze-fracture replica labelling (SDS-FRL) techniques. Histoblots showed that GluN1 expression was significantly reduced in the hippocampus in a layer-dependent manner, in the cortex and the caudate putamen of APP/PS1 transgenic mice at 12 months of age but was unaltered at 1 and 6 months. Using quantitative SDS-FRL, we unravelled the molecular organisation of GluN1 in seven excitatory synapse populations at a high spatial resolution in the CA1 and CA3 fields and the DG of the hippocampus in 12-month-old APP/PS1 mice. In the CA1 field, the labelling density for GluN1 in the excitatory synapses established on spines and interneurons, was significantly reduced in APP/PS1 mice compared to age-matched wild-type mice in the stratum lacunosum-moleculare but unaltered in the stratum radiatum. In the CA3 field, synaptic GluN1 was reduced in mossy fibre-CA3 pyramidal cell synapses but unaltered in the A/C-CA3 pyramidal cell synapses. In the DG, the density of GluN1 in granule cell-perforant pathway synapses was reduced in APP/PS1 mice. Altogether, our findings provide evidence of specific alterations of synaptic GluN1 in the trisynaptic circuit of the hippocampus in Aß pathology. This differential vulnerability in the disruption of NMDARs may be involved in the mechanisms causing abnormal network activity of the hippocampal circuit and cognitive impairment characteristic of APP/PS1 mice.
Assuntos
Doença de Alzheimer , Hipocampo , Receptores de N-Metil-D-Aspartato , Sinapses , Animais , Masculino , Camundongos , Doença de Alzheimer/patologia , Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/metabolismo , Modelos Animais de Doenças , Hipocampo/metabolismo , Hipocampo/patologia , Camundongos Transgênicos , Receptores de N-Metil-D-Aspartato/metabolismo , Sinapses/metabolismo , Sinapses/patologiaRESUMO
Alzheimer's disease (AD) constitutes a major public-health issue of our time. Regrettably, despite our considerable understanding of the pathophysiological aspects of this disease, current interventions lead to poor outcomes. Furthermore, experimentally promising compounds have continuously failed when translated to clinical trials. Along with increased population ageing, Type 2 Diabetes Mellitus (T2DM) has become an extremely common condition, mainly due to unbalanced dietary habits. Substantial epidemiological evidence correlates T2DM with cognitive impairment as well. Considering that brain insulin resistance, mitochondrial dysfunction, oxidative stress, and amyloidogenesis are common phenomena, further approaching the common features among these pathological conditions. Metformin constitutes the first-choice drug to preclude insulin resistance in T2DM clinical management. Experimental evidence suggests that its functions might include neuroprotective effects, in addition to its hypoglycemic activity. This review aims to summarize and discuss current knowledge of experimental data on metformin on this path towards translational medicine. Finally, we discuss the controversial data of responses to metformin in vitro, and in vivo, animal models and human studies.
Assuntos
Doença de Alzheimer , Diabetes Mellitus Tipo 2 , Hipoglicemiantes , Metformina , Doença de Alzheimer/tratamento farmacológico , Doença de Alzheimer/metabolismo , Metformina/uso terapêutico , Metformina/farmacologia , Humanos , Animais , Hipoglicemiantes/uso terapêutico , Hipoglicemiantes/farmacologia , Diabetes Mellitus Tipo 2/tratamento farmacológico , Diabetes Mellitus Tipo 2/metabolismo , Pesquisa Translacional Biomédica/métodos , Fármacos Neuroprotetores/uso terapêutico , Fármacos Neuroprotetores/farmacologia , Resistência à Insulina/fisiologiaRESUMO
Alterations in cognitive and non-cognitive cerebral functions characterize Alzheimer's disease (AD). Cortical and hippocampal impairments related to extracellular accumulation of Aß in AD animal models have been extensively investigated. However, recent reports have also implicated intracellular Aß in limbic regions, such as the nucleus accumbens (nAc). Accumbal neurons express high levels of inhibitory glycine receptors (GlyRs) that are allosterically modulated by ethanol and have a role in controlling its intake. In the present study, we investigated how GlyRs in the 2xTg mice (AD model) affect nAc functions and ethanol intake behavior. Using transgenic and control aged-matched litter mates, we found that the GlyRα2 subunit was significantly decreased in AD mice (6-month-old). We also examined intracellular calcium dynamics using the fluorescent calcium protein reporter GCaMP in slice photometry. We also found that the calcium signal mediated by GlyRs, but not GABAAR, was also reduced in AD neurons. Additionally, ethanol potentiation was significantly decreased in accumbal neurons in the AD mice. Finally, we performed drinking in the dark (DID) experiments and found that 2xTg mice consumed less ethanol on the last day of DID, in agreement with a lower blood ethanol concentration. 2xTg mice also showed lower sucrose consumption, indicating that overall food reward was altered. In conclusion, the data support the role of GlyRs in nAc neuron excitability and a decreased glycinergic activity in the 2xTg mice that might lead to impairment in reward processing at an early stage of the disease.
Assuntos
Doença de Alzheimer , Núcleo Accumbens , Receptores de Glicina , Camundongos , Doença de Alzheimer/metabolismo , Núcleo Accumbens/metabolismo , Receptores de Glicina/metabolismo , Camundongos Endogâmicos C57BL , Etanol , Camundongos Transgênicos , Cálcio/metabolismo , Recompensa , Sacarose/metabolismo , Atividade Motora , Ansiedade , Neurônios/metabolismoRESUMO
Dendritic spine features in human neurons follow the up-to-date knowledge presented in the previous chapters of this book. Human dendrites are notable for their heterogeneity in branching patterns and spatial distribution. These data relate to circuits and specialized functions. Spines enhance neuronal connectivity, modulate and integrate synaptic inputs, and provide additional plastic functions to microcircuits and large-scale networks. Spines present a continuum of shapes and sizes, whose number and distribution along the dendritic length are diverse in neurons and different areas. Indeed, human neurons vary from aspiny or "relatively aspiny" cells to neurons covered with a high density of intermingled pleomorphic spines on very long dendrites. In this chapter, we discuss the phylogenetic and ontogenetic development of human spines and describe the heterogeneous features of human spiny neurons along the spinal cord, brainstem, cerebellum, thalamus, basal ganglia, amygdala, hippocampal regions, and neocortical areas. Three-dimensional reconstructions of Golgi-impregnated dendritic spines and data from fluorescence microscopy are reviewed with ultrastructural findings to address the complex possibilities for synaptic processing and integration in humans. Pathological changes are also presented, for example, in Alzheimer's disease and schizophrenia. Basic morphological data can be linked to current techniques, and perspectives in this research field include the characterization of spines in human neurons with specific transcriptome features, molecular classification of cellular diversity, and electrophysiological identification of coexisting subpopulations of cells. These data would enlighten how cellular attributes determine neuron type-specific connectivity and brain wiring for our diverse aptitudes and behavior.
Assuntos
Doença de Alzheimer , Espinhas Dendríticas , Humanos , Tonsila do Cerebelo , Neurônios , FilogeniaRESUMO
Metabolic syndrome (MetS), a cluster of metabolic conditions that include obesity, hyperlipidemia, and insulin resistance, increases the risk of several aging-related brain diseases, including Alzheimer's disease (AD). However, the underlying mechanism explaining the link between MetS and brain function is poorly understood. Among the possible mediators are several adipose-derived secreted molecules called adipokines, including adiponectin (ApN) and resistin, which have been shown to regulate brain function by modulating several metabolic processes. To investigate the impact of adipokines on MetS, we employed a diet-induced model to induce the various complications associated with MetS. For this purpose, we administered a high-fat diet (HFD) to both WT and APP/PSN1 mice at a pre-symptomatic disease stage. Our data showed that MetS causes a fast decline in cognitive performance and stimulates Aß42 production in the brain. Interestingly, ApN treatment restored glucose metabolism and improved cognitive functions by 50% while decreasing the Aß42/40 ratio by approximately 65%. In contrast, resistin exacerbated Aß pathology, increased oxidative stress, and strongly reduced glucose metabolism. Together, our data demonstrate that ApN and resistin alterations could further contribute to AD pathology.
Assuntos
Doença de Alzheimer , Síndrome Metabólica , Animais , Camundongos , Adiponectina , Resistina , Doença de Alzheimer/etiologia , Adipocinas , Obesidade , GlucoseRESUMO
The spectrum of neurodegenerative diseases that primarily affect cognition and behaviorspreads from asymptomatic preclinical disease to very mild cognitive impairment to frank dementia. Alzheimer's disease (AD) is the most common cause of a decline in cognitive ability. Also, it is a devastating condition that affects patients and their entirefamilies of caregivers, exacting tremendous financial hardships. Diagnosis may be complicated by other forms of dementia that have symptoms and pathologies similar to AD. Knowing the key features and pathology of each type of dementia can help in the accurate diagnosis of patients, so they will receive the treatment and support services appropriate for their condition and maintain the highest possible functioning in daily life and quality of life. Differentiate, based on clinical criteria, neuropathology, and biomarkers, AD and its atypical variants from other common dementias including Dementia with Lewy Bodies, Vascular Cognitive Impairment, Frontotemporal Degeneration, and less frequent cognitive disorders. The importance of getting an accurate and early diagnosis of dementiais now increasingly significant to make important decisions about treatment, support, and care. Nonpharmacological as well as pharmacological interventions should be initiated once the diagnosis is obtained. Biochemical markers to identify Alzheimer's disease play a central role in the new diagnostic criteria for the disease and in the recent biological definition of AD. This review article presents up-to-date data regarding the recent diagnostic criteria of Alzheimer´s disease and related disorders, emphasizing its usefulness in routine clinical practice.
El espectro de enfermedades neurodegenerativas que afectan principalmente a la cognición y el comportamiento abarca desde la enfermedad preclínica asintomática hasta el deterioro cognitivo muy leve y la demencia franca. La enfermedad de Alzheimer (EA) es la causa más común de deterioro de la capacidad cognitiva. Es una enfermedad devastadora que afecta a los pacientes y a toda su familia de cuidadores, lo que supone enormes dificultades socioeconómicas y psicoemocionales. El diagnóstico puede complicarse debido a otras formas de demencia que presentan síntomas y patologías similares a la EA. Los marcadores bioquímicos para identificar la enfermedad de Alzheimer desempeñan un papel central en los nuevos criterios diagnósticos de la enfermedad y en la reciente definición biológica de la EA. Conocer las características claves y la patología de cada tipo de demencia puede ayudar en el diagnóstico preciso de los pacientes, a fin de que reciban el tratamiento y los servicios de apoyo adecuados a su condición y mantengan el mayor funcionamiento posible en la vida diaria y la calidad de vida. Por lo tanto es prioritario diferenciar, basándose en criterios clínicos, neuropatología y biomarcadores, la EA y sus variantes atípicas de otras demencias comunes como el Deterioro Cognitivo Vascular, la Degeneración Fronto- temporal entre otras, y los trastornos cognitivos menos frecuentes. Este artículo de revisión presenta datos actualizados relativos a los recientes criterios diagnósticos de algunas formas de demencia haciendo hincapié en su utilidad en la práctica clínica habitual. Se exponen los criterios de EA, de Demencia Vascular (DV), de la demencia Fronto-temporal (DFT) y de una forma rara de demencia, descripta en los últimos años, que se evidencia en pacientes muy añosos con un perfil similar a la EA. Se trata de la encefalopatía predominantemente límbica por tdp- 43 relacionada a la edad (LATE).
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Doença de Alzheimer , Humanos , Doença de Alzheimer/diagnóstico , Estudos RetrospectivosRESUMO
A homeopatia é uma especialidade odontológica, componente das práticas integrativas e complementares sendo regida pelo princípio da similaridade. Sua prática é geralmente utilizada no controle de doenças, sendo muito indicada naquelas que acometem os idosos de forma crônica, como a Doença de Alzheimer que pode causar a xerostomia (secura bucal) nos pacientes. O objetivo deste trabalho foi realizar uma revisão de literatura sobre a homeopatia como uma opção terapêutica na secura bucal em pacientes com Doença de Alzheimer. A Homeopatia pode atuar de forma interdisciplinar junto ao tratamento convencional não substituindo um pelo outro, sendo necessário uma anamnese minuciosa para coleta de sintomas, tornando imprescindível incluir manifestações mentais, gerais e locais na repertorização, individualizando-a ao máximo, já que a escolha do medicamento homeopático e o sucesso no tratamento está na dependência da totalidade dos sintomas com as suas modalidades. Entretanto como não há estudos suficientes que relacionam a homeopatia com a melhora da secura bucal em pacientes com Doença de Alzheimer, mais pesquisas são indicadas para comprovar a efetividade no tratamento.
Homeopathy is a dental specialty, a component of integrative and complementary practices, governed by the principle of similarity. Its practice is generally used in the control of diseases, being highly indicated in those that affect the elderly in a chronic way, such as Alzheimer's disease, which can cause xerostomia (dry mouth) in patients. The objective of this work was to carry out a literature review about homeopathy as a therapeutic option for dry mouth in patients with Alzheimer's disease. Homeopathy can act in an interdisciplinary way together with conventional treatment, not substituting one for the other, requiring a thorough anamnesis to collect symptoms, making it essential to include mental, general and local manifestations in the repertorization, individualizing it to the maximum, since the choice of the homeopathic medicine and the success of the treatment depends on the totality of the symptoms with their modalities. However, as there are not enough studies that relate homeopathy with the improvement of dry mouth in patients with Alzheimer's disease, more research is indicated to prove the effectiveness of the treatment
Assuntos
Humanos , Xerostomia/terapia , Medicamento Homeopático , Terapêutica Homeopática , Doença de Alzheimer/complicaçõesRESUMO
Late onset Alzheimer´s disease (AD) is a neurodegenerative disease with gender differences in its onset and progression, being the prevalence predominant in women and at an earlier age than in men. The pathophysiology of the menopausal condition has been associated to this dementia, playing major roles regarding both endocrine and glucose metabolism changes, amongst other mechanisms. In the current review we address the role of estrogen deficiency in the processes involved in the development of AD, including amyloid precursor protein (APP) processing to form senile plaques, Tau phosphorylation forming neurofibrillary tangles, Wnt signaling and AD neuropathology, the role of glucose brain metabolism, Wnt signaling and glucose transport in the brain, and our research contribution to these topics.
Assuntos
Doença de Alzheimer , Doenças Neurodegenerativas , Masculino , Feminino , Humanos , Doença de Alzheimer/metabolismo , Proteínas tau , Doenças Neurodegenerativas/metabolismo , Via de Sinalização Wnt , Menopausa , GlucoseRESUMO
Insulin, a key pleiotropic hormone, regulates metabolism through several signaling pathways in target tissues including skeletal muscle, liver, and brain. In the brain, insulin modulates learning and memory, and impaired insulin signaling is associated with metabolic dysregulation and neurodegenerative diseases. At the receptor level, in aging and Alzheimer's disease (AD) models, the amount of insulin receptors and their functions are decreased. Clinical and animal model studies suggest that memory improvements are due to changes in insulin levels. Furthermore, diabetes mellitus (DM) and insulin resistance are associated with age-related cognitive decline, increased levels of ß-amyloid peptide, phosphorylation of tau protein; oxidative stress, pro-inflammatory cytokine production, and dyslipidemia. Recent evidence shows that deleting brain insulin receptors leads to mild obesity and insulin resistance without influencing brain size and apoptosis development. Conversely, deleting insulin-like growth factor 1 receptor (IGF-1R) affects brain size and development, and contributes to behavior changes. Insulin is synthesized locally in the brain and is released from the neurons. Here, we reviewed proposed pathophysiological hypotheses to explain increased risk of dementia in the presence of DM. Regardless of the exact sequence of events leading to neurodegeneration, there is strong evidence that mitochondrial dysfunction plays a key role in AD and DM. A triple transgenic mouse model of AD showed mitochondrial dysfunction, oxidative stress, and loss of synaptic integrity. These alterations are comparable to those induced in wild-type mice treated with sucrose, which is consistent with the proposal that mitochondrial alterations are associated with DM and contribute to AD development. Alterations in insulin/IGF-1 signaling in DM could lead to mitochondrial dysfunction and low antioxidant capacity of the cell. Thus, insulin/IGF-1 signaling is important for increased neural processing and systemic metabolism, and could be a specific target for therapeutic strategies to decrease alterations associated with age-related cognitive decline.
RESUMO
Dementia in Latin America is a crucial public health problem. Identifying brief cognitive screening (BCS) tools for the primary care setting is crucial, particularly for illiterate individuals. We evaluated tool performance characteristics and validated the free and total recall sections of the Free and Cued Selective Reminding Test-Picture version (FCSRT-Picture) to discriminate between 63 patients with early Alzheimer's disease dementia (ADD), 60 amnestic mild cognitive impairment (aMCI) and 64 cognitively healthy Peruvian individuals with illiteracy from an urban area. Clinical, functional, and cognitive assessments were performed. FCSRT-Picture performance was assessed using receiver operating characteristic curve analyses. The mean ± standard deviation scores were 7.7 ± 1.0 in ADD, 11.8 ± 1.6 in aMCI, and 29.5 ± 1.8 in controls. The FCSRT-Picture had better performance characteristics for distinguishing controls from aMCI compared with several other BCS tools, but similar characteristics between controls and early ADD. The FCSRT-Picture is a reliable BCS tool for illiteracy in Peru.
Assuntos
Doença de Alzheimer , Disfunção Cognitiva , Sinais (Psicologia) , Humanos , Alfabetização , Testes Neuropsicológicos , PeruRESUMO
BACKGROUND: Psychological stress may be a risk factor for dementia, but the association between exposure to stressful life events and the development of cognitive dysfunction has not been conclusively demonstrated. We hypothesize that if a stressful event has an impact on the subjects, its effects would be different in the three diseases. OBJECTIVE: This study aims to assess the effects of stressful events in senior patients who later developed ischemic stroke, Alzheimer's, or Parkinson's disease. MATERIAL AND METHODS: Together with demographic variables (age, sex, race, socioeconomic and cultural levels), five types of past stressful events, such as death or serious illness of close relatives, job dismissal, change of financial status, retirement, and change of residence, were recorded in 1024 patients with Alzheimer's disease, Parkinson's disease, and ischemic stroke. Time-todiagnosis (months from the event to the first symptoms: retrospective study) and evolution time (years of follow-up of each patient: prospective study) were recorded. The variance and nonparametric methods were analyzed to the variables time-to-diagnosis and evolution time to analyze differences between these diseases. RESULTS: The demographic variables, such as age, sex, race, economic and cultural levels, were found to be statistically non-significant; differences in the economic level were significant (P<0.05). Significant differences (P<0.001) were found in the mean time-to-diagnosis between diseases (Alzheimer's disease>Parkinson's disease >Stroke), and minor differences (P<0.05) in evolution time. CONCLUSION: Differences in time-to-diagnosis between the diseases indicate that the stressful effect of having experienced the death or serious illness of a close relative has an impact on their emergence. The measurement of time-to-diagnosis and evolution time proves useful in detecting differences between diseases.
Assuntos
Doença de Alzheimer , AVC Isquêmico , Doença de Parkinson , Idoso , Doença de Alzheimer/diagnóstico , Humanos , Acontecimentos que Mudam a Vida , Estudos Prospectivos , Estudos RetrospectivosRESUMO
Spices and herbs have been used for medicinal purposes for centuries. Also, in the last decades, the use of different nutritional supplements has been implemented to treat all kinds of diseases, including those that present an alteration in cognitive functioning. Dementia is a clinical syndrome in which a person's mental and cognitive capacities gradually decline. As the disease progresses, the person's autonomy diminishes. As there is not an effective treatment to prevent progressive deterioration in many of these pathologies, nutritional interventions have been, and still are, one of the most widely explored therapeutic possibilities. In this review, we have discussed a great number of potentially interesting plants, nutritional derivatives, and probiotics for the treatment of dementia around the world. Their action mechanisms generally involve neuroprotective effects via anti-inflammatory, antioxidant, anti-apoptotic, b-amyloid, and tau anti-aggregate actions; brain blood flow improvement, and effects on synaptic cholinergic and dopaminergic neurotransmission, which may optimize cognitive performance in patients with cognitive impairment. As for their efficacy in patients with cognitive impairment and/or dementias, evidence is still scarce andthe outcomes are controversial. We consider that many of these substances have promising therapeutic properties. Therefore, the scientific community has to continue with a complete research focused on both identifying possible action mechanisms and carrying out clinical trials, preferably randomized, double-blind ones, with a greater number of patients, a long-term follow-up, dose standardization, and the use of current diagnostic criteria.
Assuntos
Demência/tratamento farmacológico , Suplementos Nutricionais , Plantas Medicinais , Doença de Alzheimer/tratamento farmacológico , Antioxidantes/uso terapêutico , Cognição/efeitos dos fármacos , Transtornos Cognitivos/tratamento farmacológico , HumanosRESUMO
BACKGROUND: Anti-hypertensive medications may reduce the incidence of cognitive disorders. This may be due to reasons beyond their pure hypotensive effect. This study aimed to systematically review the association between the use of Angiotensin-Receptor Blockers (ARBs) and the incidence of Alzheimer's disease (AD). METHODS: We systematically searched studies reporting the association between ARB use and the incidence of AD. RESULTS: Ten studies (1 RCT, 2 case-control and 7 cohort studies) met the inclusion criteria. When all observational studies (9) were analyzed, ARB use was associated with a reduced risk of incident AD (HR 0.72, 95% CI: 0.58-0.88, p<0.001). In the only RCT, decrease in the incidence of AD was also significant (HR= 0.31, 95% CI: 0.14-0.68). CONCLUSION: ARB use may reduce the risk of incident AD. This association does not imply causation and further research is required to clarify potential mechanisms.
Assuntos
Doença de Alzheimer , Antagonistas de Receptores de Angiotensina , Anti-Hipertensivos , Doença de Alzheimer/epidemiologia , Doença de Alzheimer/prevenção & controle , Antagonistas de Receptores de Angiotensina/uso terapêutico , Inibidores da Enzima Conversora de Angiotensina/uso terapêutico , Angiotensinas/uso terapêutico , Anti-Hipertensivos/uso terapêutico , HumanosRESUMO
Introducción: Varias enfermedades neurodegenerativas están asociadas a la ocurrencia de acortamiento de los telómeros, y los convierten en biomarcadores y dianas terapéuticas potenciales. Objetivo: Reflejar la relevancia del acortamiento de los telómeros para enfermedades neurodegenerativas, y destacar sus implicaciones Material y métodos: Se realizó una revisión bibliográfica durante los meses de septiembre de 2019 a enero de 2020. Fueron consultadas bases de datos de referencia, con el uso de descriptores y operadores booleanos. La estrategia de búsqueda avanzada para la selección de los artículos fue empleada, teniendo en cuenta la calidad metodológica o validez de los estudios. Desarrollo: Fueron identificadas evidencias sólidas de asociación entre el acortamiento de los telómeros y las enfermedades de Alzheimer y Huntington, que sugieren un papel relevante de la biología de los telómeros en la fisiopatología de estas enfermedades. Las evidencias disponibles hasta el momento no permiten establecer la relevancia de la biología de los telómeros en la fisiopatología de la Enfermedad de Parkinson o de la esclerosis lateral amiotrófica. Se obtuvieron evidencias de la utilidad de terapias orientadas a la prevención del acortamiento de los telómeros para el tratamiento de enfermedades neurodegenerativas. Conclusiones: El acortamiento de los telómeros es de relevancia fisiopatológica y clínica para las enfermedades de Alzheimer y Huntington, mientras que existen evidencias insuficientes para establecer su importancia en la Enfermedad de Parkinson y la esclerosis lateral amiotrófica. El uso de estrategias para estimular la actividad de la telomerasa tiene potenciales aplicaciones terapéuticas en el contexto de enfermedades neurodegenerativas(AU)
Introduction: Several neurodegenerative disorders are associated with telomere attrition, turning telomeres into potential biomarkers and potential therapeutic targets. Objective: To assess the relevance of telomere attrition for neurodegenerative disorders, highlighting its therapeutic implications. Material and methods: A literature review was carried out from September 2019 to January 2020. Several databases were searched by using descriptors and Boolean operators. Advanced search strategy was used for the selection of articles, taking into account the methodological quality and validity of the studies. Results: Strong evidence for an association between telomere attrition and Alzheimer and Huntington diseases was obtained, suggesting a potential importance of telomere biology in the physiopathology of these diseases. Current evidence does not allow establishing the relevance of telomere attrition in the physiopathology of Parkinson´s disease or Amyotrophic Lateral Sclerosis. Evidence was obtained for the usefulness of therapies for the prevention of telomere attrition in the treatment of neurodegenerative disorders. Conclusions: Telomere attrition has physiopathological and clinical relevance in Alzheimer´s and Huntington´s diseases, though current evidence is not enough to establish its role in Parkinson's disease and Amyotrophic Lateral Sclerosis. Strategies that enhance telomerase activity have therapeutic potential in the context of neurodegenerative disorders(AU)
Assuntos
Humanos , Transtornos Heredodegenerativos do Sistema Nervoso/genética , Encurtamento do Telômero/genéticaRESUMO
INTRODUCTION: Social Cognition (SC) is a complex construct that reflects a wide variety of implicit and explicit cognitive processes. Many neurocognitive domains are associated with SC and the Executive Function (EF) is the most representative one. We conducted a systematic review aiming at clarifying whether SC impairments are associated with dysfunction on EF in people with Alzheimer Disease (AD). METHODS: The search, based on the Preferred Reporting Items for Systematic Reviews and Meta- Analyses (PRISMA), was undertaken between January 2007 and December 2019 using Pubmed, SciELO, BIREME and Thomson Reuters Web of Science electronic databases. The keywords were SC, AD, EF, Neuropsychological functioning and Executive Disorder. RESULTS: One hundred thirty-six articles were identified and fifteen were included. These studies are not in agreement about the extent of SC deficits in AD, mainly in the mild stage of the disease. EF deficits, specifically inhibition and the ability to manipulate verbal information, are associated with the impairment in SC in AD. SC decreases with the disease progression, a relationship explained by global cognition impairment and SC specific symptoms. CONCLUSION: SC impairment is associated with disease progression, mainly because of the decline in EF. Studies on SC components are unequal, contributing to a frequent generalization of Theory of Mind results, and often hampering the investigation of other components, mainly empathy. More precise knowledge about SC functioning in AD may contribute to a better understanding of the behavioral changes and interpersonal interactions.
Assuntos
Doença de Alzheimer/psicologia , Função Executiva/fisiologia , Testes Neuropsicológicos , Cognição Social , Teoria da Mente/fisiologia , Doença de Alzheimer/diagnóstico , Doença de Alzheimer/terapia , Estudos Transversais , HumanosRESUMO
High intake of omega-3 fatty acids has been associated with synaptic plasticity, neurogenesis and memory in several experimental models. To assess the efficacy of fish oil supplementation on oxidative stress markers in patients diagnosed with probable Alzheimer´s disease (AD) we conducted a double blind, randomized, placebo controlled clinical trial. AD patients who met the inclusive criteria were given fish oil (containing 0.45 g eicosapentaenoic acid and 1 g docosahexaenoic acid) or placebo daily for 12 months. Oxidative stress markers [lipoperoxides, nitric oxide catabolites levels, oxidized/reduced glutathione ratio, and membrane fluidity] and fatty acid profile in erythrocytes were assessed at enrollment, and 6 and 12 months after the start of the testing period. At the end of the trial, in patients who received fish oil, we detected a decrease in the omega 6/omega 3 ratio in erythrocyte membrane phospholipids. This change was parallel with decreases in plasma levels of lipoperoxides and nitric oxide catabolites. Conversely, the ratio of reduced to oxidized glutathione was significantly increased. In addition, membrane fluidity was increased significantly in plasma membrane samples. In conclusion fish oil administration has a beneficial effect in decreasing the levels of oxidative stress markers and improving the membrane fluidity in plasma(AU)
El alto consumo de ácidos grasos omega-3 se asocia con la plasticidad sináptica, neurogénesis y memoria en varios modelos experimentales. Para evaluar la eficacia de la suplementación con aceite de pescado en los marcadores de estrés oxidativo en pacientes con diagnóstico de la enfermedad de Alzheimer (EA) probable realizamos un ensayo clínico doble ciego, aleatorizado, controlado con placebo. A los pacientes con la EA que cumplían los criterios de inclusión se les administró aceite de pescado (que contenía 0,45 g de ácido eicosapentaenoico y 1 g de ácido docosahexaenoico) o placebo diariamente durante 12 meses. Los marcadores de estrés oxidativo plasmático [niveles de lipoperóxidos y catabolitos del óxido nítrico, cociente de glutatión reducido a glutatiónoxidado) y fluidez de la membrana] y el perfil de ácidos grasos en los eritrocitos se evaluaron al inicio, 6 meses y alos 12 meses. Al final del ensayo, en pacientes que recibieron aceite de pescado detectamos una disminución en el cociente de ácidos grasos omega 6/omega 3 en los fosfolípidos de la membrana eritrocitaria. Este cambio ocurrió en paralelo a la disminución de los niveles plasmáticos de lipoperóxidos y catabolitos del óxido nítrico. Por el contrario, el cociente de glutatión reducido a glutatión oxidado se incrementó significativamente. Además, la fluidez de la membrana aumentó significativamente en las muestras analizadas. En conclusión, la administración de aceite de pescado tiene un efecto beneficioso al disminuir los niveles de marcadores de estrés oxidativo plasmático y mejorar la fluidez de la membrana plasmática(AU)
Assuntos
Humanos , Masculino , Feminino , Óleos de Peixe , Ácidos Graxos Ômega-3 , Estresse Oxidativo , Doença de Alzheimer , Membrana Celular , Doença Crônica , NeurogêneseRESUMO
Accumulative evidence has shown that mitochondrial dysfunction plays a pivotal role in the pathogenesis of Alzheimer's disease (AD). Mitochondrial impairment actively contributes to the synaptic and cognitive failure that characterizes AD. The presence of soluble pathological forms of tau like hyperphosphorylated at Ser396 and Ser404 and cleaved at Asp421 by caspase 3, negatively impacts mitochondrial bioenergetics, transport, and morphology in neurons. These adverse effects against mitochondria health will contribute to the synaptic impairment and cognitive decline in AD. Current studies suggest that mitochondrial failure induced by pathological tau forms is likely the result of the opening of the mitochondrial permeability transition pore (mPTP). mPTP is a mitochondrial mega-channel that is activated by increases in calcium and is associated with mitochondrial stress and apoptosis. This structure is composed of different proteins, where Ciclophilin D (CypD) is considered to be the primary mediator of mPTP activation. Also, new studies suggest that mPTP contributes to Aß pathology and oxidative stress in AD. Further, inhibition of mPTP through the reduction of CypD expression prevents cognitive and synaptic impairment in AD mouse models. More importantly, tau protein contributes to the physiological regulation of mitochondria through the opening/interaction with mPTP in hippocampal neurons. Therefore, in this paper, we will discuss evidence that suggests an important role of pathological forms of tau against mitochondrial health. Also, we will discuss the possible role of mPTP in the mitochondrial impairment produced by the presence of tau pathology and its impact on synaptic function present in AD.
Assuntos
Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Mitocôndrias/metabolismo , Proteínas tau/metabolismo , Peptídeos beta-Amiloides/metabolismo , Animais , Humanos , Mitocôndrias/patologia , Neurônios/metabolismo , Neurônios/patologia , Espécies Reativas de Oxigênio/metabolismoRESUMO
Major research in Alzheimer's disease (AD) related to disease-modifying agents is concentrated on pharmacological approaches related to diagnostic markers, neurofibrillary tangles and amyloid plaques. Although most studies focus on anti-amyloid strategies, investigations on tau protein have produced significant advances in the modulation of the pathophysiology of several neurodegenerative diseases. Since the discovery of phenothiazines as tau protein aggregation inhibitors (TAGIs), many additional small molecule inhibitors have been discovered and characterized in biological model systems, which exert their interaction effects by covalent and noncovalent means. In this paper, we summarize the latest advances in the discovery and development of tau aggregation inhibitors using a specialized approach in their chemical classes. The design of new TAGIs and their encouraging use in in vivo and clinical trials support their potential therapeutic use in AD.
Assuntos
Doença de Alzheimer , Proteínas tau , Doença de Alzheimer/tratamento farmacológico , Peptídeos beta-Amiloides/metabolismo , Humanos , Emaranhados Neurofibrilares , Agregados ProteicosRESUMO
The early detection of the amyloid beta peptide aggregates involved in Alzheimer's disease is crucial to test new potential treatments. In this research, we improved the detection of amyloid beta peptide aggregates in vitro and ex vivo by fluorescence combining the use of CRANAD-2 and gold nanorods (GNRs) by the surface enhancement fluorescence effect. We synthetized GNRs and modified their surface with HS-PEG-OMe and HS-PEG-COOH and functionalized them with the D1 peptide, which has the capability to selectively bind to amyloid beta peptide. For an in vitro detection of amyloid beta peptide, we co-incubated amyloid beta peptide aggregates with the probe CRANAD-2 and GNR-PEG-D1 observing an increase in the intensity of the fluorescence signal attributed to surface enhancement fluorescence. Furthermore, the surface enhancement fluorescence effect was observed in brain slices of transgenic mice with Alzheimer´s disease co-incubated with CRANAD-2 and GNR-PEG-D1. An increase in the fluorescence signal was observed allowing the detection of aggregates that cannot be detected with the single use of CRANAD-2. Gold nanoparticles allowed an improvement in the detection of the amyloid aggregated by fluorescence in vitro and ex vivo.