ABSTRACT
Alzheimer disease (AD) is the main cause of dementia worldwide and a source of important population morbidity and mortality. It is estimate that its prevalence will increase dramatically in the upcoming years. The classical clinical presentation of AD is an amnesic hippocampal syndrome, and Mild Cognitive impairment (MCI) is considered the initial stage between normal cognition and dementia. The most accepted pathogenesis establishes amyloid beta (Ab) deposition in brain parenchyma as the initial mechanism, followed by the intracellular accumulation of hyperphosphorylated tau finally leading to the loss of synapses and neurons. Recently, the study of AD pathogenesis is focusing on immune mechanisms as main actors of disease development. Microglia is the macrophagic resident cell in the central nervous system (CNS), and initiates the inflammatory response and Ab phagocytosis, interacting with other glia and recruiting diverse immune cells to the CNS. The role of the adaptive immune system, and, especially T lymphocytes' role, is still controversial. We hypothesize that the pathogenesis of AD is dynamic; with a preponderant proinflammatory activity initially, but later on, the persistent presence of Ab due to the lack of its proper elimination leads to a phenomena of lymphocyte dysfunction and immunological tolerance that have a deleterious role at advanced stages of the disease. (AU)
Subject(s)
Humans , Male , Female , Alzheimer Disease/physiopathology , Alzheimer Disease/immunology , Dementia/immunologyABSTRACT
ABSTRACT Alzheimer's disease (AD) is the most common form of dementia. In the last 15 years, a new theory has proposed the autoimmune mechanism as a trigger for AD. Studies on the association between AD and inflammatory biomarkers have yielded controversial results. Interleukin-10 (IL-10), an anti-inflammatory mediator, has been pointed out as one of the main cytokines associated with the occurrence of AD. Moreover, treatment that increases IL-10 levels could be a potential therapy for AD, since this cytokine acts on amyloid and pro-inflammatory molecule reduction. Based on the current literature, this study reviews evidence regarding the role of IL-10 polymorphisms in the context of AD, which has been shown to be of paramount importance for attenuating neuroinflammation, cognitive dysfunction and neurodegeneration.
RESUMO A doença de Alzheimer (DA) é a forma mais comum de demência. Nos últimos 15 anos, uma nova teoria propõe um mecanismo autoimmune como o gatilho para a DA. Associações entre DA e biomarcadores inflamatórios têm sido registradas, contudo com resultados controversos. A interleucina-10 (IL-10), um mediador anti-inflamatório, tem sido apontada como uma das principais citocinas associadas com a ocorrência de DA. Além disso, os tratamentos que aumentam os níveis de IL-10 podem ser uma terapia potencial para DA, uma vez que esta citocina atua sobre a redução de substância amiloide e de moléculas pró-inflamatórias. Baseando-se em literaturas atuais, este estudo revisa evidências relacionadas com o papel da IL-10 e seus polimorfismos no contexto da DA, o qual se mostrou ser de fundamental importância para atenuar a neuroinflamação, a disfunção cognitiva e a neurodegeneração.
Subject(s)
Humans , Polymorphism, Genetic , Interleukin-10/genetics , Alzheimer Disease/genetics , Biomarkers , Disease Progression , Alzheimer Disease/immunologyABSTRACT
Abstract Alzheimer disease (AD) is the most prevalent form of dementia of adult-onset, characterized by progressive impairment in cognition and memory. There is no cure for the disease and the current treatments are only symptomatic. Drug discovery is an expensive and time-consuming process; in the last decade no new drugs have been found for AD despite the efforts of the scientific community and pharmaceutical companies. The Aβ immunotherapy is one of the most promising approaches to modify the course of AD. This therapeutic strategy uses synthetic peptides or monoclonal antibodies (mAb) to decrease the Aβ load in the brain and slow the progression of the disease. Therefore, this article will discuss the main aspects of AD neuropathogenesis, the classical pharmacologic treatment, as well as the active and passive immunization describing drug prototypes evaluated in different clinical trials.
Resumen La enfermedad de Alzheimer (EA) es la forma más frecuente de demencia de inicio en el adulto, caracterizada por un deterioro progresivo en la cognición y la memoria. No hay cura para la enfermedad y los tratamientos actuales son sólo sintomáticos. El descubrimiento de fármacos es un proceso costoso y que consume mucho tiempo; en la última década no se han encontrado nuevos fármacos para la EA a pesar de los esfuerzos de la comunidad científica y las compañías farmacéuticas. La inmunoterapia contra Aβ es uno de los enfoques más prometedores para modificar el curso de la EA. Esta estrategia terapéutica utiliza péptidos sintéticos o anticuerpos monoclonales (mAb) para disminuir la carga de Aβ en el cerebro y retardar la progresión de la enfermedad. Por lo tanto, este artículo discutirá los principales aspectos de la neuropatogénesis de la EA, el tratamiento farmacológico clásico, así como la inmunización activa y pasiva describiendo los prototipos de fármacos evaluados en diferentes ensayos clínicos.
Subject(s)
Humans , Amyloid beta-Peptides/immunology , Alzheimer Disease/therapy , Immunotherapy/methods , Peptides/therapeutic use , Peptides/pharmacology , Disease Progression , Alzheimer Disease/physiopathology , Alzheimer Disease/immunology , Antibodies, Monoclonal/therapeutic use , Antibodies, Monoclonal/pharmacologyABSTRACT
Alzheimer's disease (AD) is the most common form of dementia caused by neurodegenerative process and is tightly related to amyloid beta (Abeta) and neurofibrillary tangles. The lack of early diagnostic biomarker and therapeutic remedy hinders the prevention of increasing population of AD patients every year. In spite of accumulated scientific information, numerous clinical trials for candidate drug targets have failed to be preceded into therapeutic development, therefore, AD-related sufferers including patients and caregivers, are desperate to seek the solution. Also, effective AD intervention is desperately needed to reduce AD-related societal threats to public health. In this review, we summarize various drug targets and strategies in recent preclinical studies and clinical trials for AD therapy: Allopathic treatment, immunotherapy, Abeta production/aggregation modulator, tau-targeting therapy and metabolic targeting. Some has already failed in their clinical trials and the others are still in various stages of investigations, both of which give us valuable information for future research in AD therapeutic development.
Subject(s)
Humans , Alzheimer Disease/immunology , Amyloid beta-Peptides/antagonists & inhibitors , Antibodies, Monoclonal/therapeutic use , Brain/metabolism , Immunotherapy , N-Methylaspartate/therapeutic use , tau Proteins/antagonists & inhibitorsABSTRACT
The progressive increase in life expectancy of the world population has fostered a major concern in order to find effective avenues for diagnosis of treatment of Alzheimer's disease (AD). Even tough AD pathogenesis is still unclear, new advances have allowed to understand that exposure of individuals to a series of environmental risk factors, named to as damage signals, play a main role in triggering the disease. This is important for AD prevention but also for the search of new treatment approaches. Activation of innate immunity in the central nervous system (CNS), essentially microglial cells, appears to be a key element in the neurodegenerative pathway As a matter of fact, when microglia cells are exposed continuously to damage signals such as metabolites from conditions of hyperlipidemia, hyperglycemia, oxidative stress, head injury and trauma, recurrent infections, in addition to supramolecular aggregates such as tau filaments or b-amyloid oligomers, among other anomalous protein filaments, they respond by triggering the inflammatory cascade. On this basis, we have postulated the neuroimmunomodulation hypothesis for Alzheimer's Disease. Therefore, we postulates that a long-term activation of brain innate immunity by a converging set of damage signals constitute a unifying mechanism that triggers the inflammatory cascade, thus leading to irreversible alteration in the neuronal cytoskeleton. These concerted alterations in signaling mechanisms will lead in neuronal cells to a final common pathway, tau hyperphosphorylations, with the consequent self-aggregation of modified tau and formation of paired helical filaments (PHFs), as the main triggering event for neurodegenration in AD.
El constante aumento en la expectativa de vida en la población mundial ha incrementado la preocupación hacia la búsqueda de la comprensión de la Enfermedad de Alzheimer (EA), así como de su diagnóstico temprano y tratamiento. Actualmente la etiopatogenia que conduce al desarrollo de la EA es aún difusa, pero se ha llegado a comprender que la exposición a una serie de distintos factores de riesgo, o señales de daño, está asociada al desencadenamiento de la EA. Esto es muy importante no solo para la prevención de esta devastadora enfermedad sino también para la búsqueda de avenidas efectivas para su tratamiento. En efecto, la activación de la inmunidad innata en el sistema nervioso central (SNC), esencialmente por las células microgliales, son un elemento clave en el proceso neurodegenerativo, cuando éstas son expuestas por períodos prolongados a señales de daño. Entre éstas están la hiperlipidemia, hiperglicemia, estrés oxidativo, traumatismos, infecciones recurrentes, oligomeros de -amiloide, agregados de tau, entre otros factores, los que desencadenarían una respuesta pro-inflamatoria persistente que conduce a la cascada neurodegenerativa. En base a esto, hemos postulado la teoría de la neuroinmunomodulación en la EA, y proponemos que la activación a largo plazo del sistema inmune innato por un conjunto de señales de daño constituye un mecanismo unificado que gatillo, una cascada inflamatoria que conduce a alteraciones irreversibles en el citoesqueleto. Estos mecanismos anómalos de señalización molecular llevarían a una vía final común que es la hiperfosforilación de la proteína tau, su autoagregación y formación de los PHFs, como desencadenantes claves en la neurodegeneración y desarrollo de la EA.
Subject(s)
Humans , Alzheimer Disease/immunology , Inflammation/immunology , Central Nervous System/immunology , Cytokines , Immunity, Innate/immunology , Microglia/immunology , Neuroimmunomodulation , Neurofibrillary Tangles/immunology , Precipitating Factors , Risk Factors , tau ProteinsABSTRACT
In 1906 Alois Alzheimer, described the cerebral lesions characteristic of the disorder that received his name: senile plaques and neurofibrillary tangles. Alzheimer's disease (AD) is now, 100 years after, the most prevalent form of dementia in the world. The longer life expectancy and aging of the population renders it as a serious public health problem of the future. Urgent methods of diagnosis and treatment are required, since the definitive diagnosis of AD continues to be neuropathologic. In the last 30 years several drugs have been approved to retard the progression of the disease; however, there are still no curative or preventive treatments. Although still in experimentation, the visualization of amyloid deposition by positron emission tomography or magnetic resonance imaging will allow in vivo diagnosis of AD. In addition, experiments with the amyloid vaccine are still ongoing, and very recent data suggest that intravenous gammaglobulins may be beneficial and safe for the treatment of AD.
Subject(s)
Animals , Humans , Mice , Alzheimer Disease/therapy , Alzheimer Vaccines/therapeutic use , Amyloid beta-Peptides/therapeutic use , Immunotherapy/methods , Peptide Fragments/therapeutic use , Plaque, Amyloid , Alzheimer Disease/diagnosis , Alzheimer Disease/immunology , Amyloid beta-Peptides/cerebrospinal fluid , Amyloid beta-Peptides/immunology , Neurofibrillary Tangles , Peptide Fragments/cerebrospinal fluid , Peptide Fragments/immunology , Positron-Emission Tomography , tau Proteins/cerebrospinal fluid , tau Proteins/immunologyABSTRACT
Neurologistas e psiquiatras lentamente voltam sua atenção para o processo inflamatório na fisiopatogenia das doenças mentais. O papel das interleucinas e outras citocinas que participam do processo inflamatório está sendo cada vez mais estudado nestas especialidades. Já existem evidências de que as citocinas estão envolvidas em doenças diversas e variadas como diabetes melito tipo 1, artrite reumatóide e asma, bem como esclerose múltipla e doença de Parkinson. Mas outras doenças neuropsiquiátricas como a esquizofrenia, a depressão e a doença de Alzheimer também parecem ter em sua fisiopatogenia uma participação do processo inflamatório que precisa de maiores esclarecimentos. Neste sentido apresentamos uma breve revisão dos possíveis agentes envolvidos nas doenças mentais, como neurotransmissores, estresse oxidativo, excitotoxicidade, apoptose e o processo inflamatório.
Subject(s)
Humans , Apoptosis , Central Nervous System , Depression/immunology , Alzheimer Disease/immunology , Inflammation/immunology , Mental Disorders , Neurotransmitter Agents , Oxidative Stress , SchizophreniaABSTRACT
Na doenca de Alzheimer (DA), os principais eventos associados a neurodegeneracao sao a formacao de placas senis e de emaranhados neurofibrilares. Estes fenomenos relacionam-se respectivamente a deposicao de beta-amiloide (Ab) e a alteracoes do estado de fosforilacao da proteina Tau. Esta e componente essencial dos microtubulos, onde se encontra em estado polimerizado. A estabilidade do polimero depende do grau de fosforilacao da Tau, tornando-se mais instavel quanto mais fosforilada a proteina. Consequentemente, a hiperfosforilacao da Tau relaciona-se com menor estabilidade do citoesqueleto, favorecendo a morte neuronal. O Ab e produzido pela clivagem da proteina precursora do amiloide (APP) por acao da enzima beta-secretase, em detrimento da acao mais fisiologica da alfa-secretase, que da origem ao fragmento APPs. As fibras de Ab tem diversos efeitos neurotoxicos, alem de ocorrerem associadamente a uma presumivel perda funcional do metabolito secretado APPs...
Subject(s)
Animals , Rats , Alzheimer Disease/enzymology , Neurodegenerative Diseases/enzymology , Phosphorylation , Acetylcholine/analysis , Acetylcholine/metabolism , Blotting, Western , Neurofibrillary Tangles , Plaque, Amyloid , Electrophoresis , Antibodies, Monoclonal/analysis , Antibodies, Monoclonal/immunology , /analysis , /metabolism , Cholinergic Agonists/analysis , Cholinergic Agonists/metabolism , Alzheimer Disease/diagnosis , Alzheimer Disease/immunology , Neurodegenerative Diseases/diagnosis , Neurodegenerative Diseases/immunology , Amyloid beta-Protein Precursor/analysis , tau Proteins/analysisABSTRACT
The two-site enzyme immunoassasy (EIA) using the monoclonal antibody (MAb) 27/21 is a valuable method capable of detecting mouse and human NGF quantitatively (Soderstrom et al., 1990). The presence of NGF in serum has been controversial, since t6he previous assay methods failed to detect circulating NGF. Recently, we described the immunological detection of low levels of NGF in human serum samples and introduced a blocking test validating the specificity of the immunoreactivity for NGF in human serum (Lorigados et al., 1982). In the present work, we applied this two-site EIA using monoclonal NGF antibody 27/21 in the study of NGF serum levels from diverse neurodegenerative disorders. We also studied evolutive samples of Parkinson's patients that received neural transplant