Grandfathers-to-grandsons transgenerational transmission of exercise positive effects on cognitive performance.

Physical exercise is a robust lifestyle intervention. Among its many benefits, it is known for its enhancement of cognitive abilities. Nevertheless, the extent to which these benefits can be transmitted across generations (intergenerational inheritance to F1, and transgenerational to F2 and beyond) remains a topic of limited comprehension. We have already shown that cognitive improvements resulting from physical exercise can be inherited from parents to their offspring, proving intergenerational effects. So, we set out to explore whether these enhancements might extend transgenerationally, impacting the F2 generation. In this study, we initially examined the behavioral traits of second-generation (F2) male mice, whose grandfathers (F0) had an exercise intervention. Our findings revealed that F2 mice with physically active F0 grandparents displayed significantly improved memory recall, encompassing both spatial and non-spatial information when compared to their counterparts from sedentary F0 progenitors, and proving for the first time the transgenerational inheritance of physical exercise-induced cognitive enhancement. Surprisingly, while F2 memory improved (as in F1), adult hippocampal neurogenesis remained unchanged between experimental and control groups (unlike in F1). Additionally, our analysis of smallRNA sequences in hippocampus identified 35 differentially expressed miRNAs linked to important brain function categories. Notably, two of these miRNAs, miRNA-144 and miRNA-298, displayed robust negative correlation with cognitive performance. These findings highlight enduring transgenerational transmission of cognitive benefits associated with exercise, even after two generations. Furthermore, they suggest that moderate exercise training can have lasting positive effects, possibly orchestrated by a specific set of miRNAs that exert their influence across multiple generations.Significance Statement Physical exercise is well known by its positive effects on body health and specifically on brain functioning and health. Here we test whether those effects are inherited from exercised grandparents to the second generation. We report here for the first time the transgenerational inheritance of moderate exercise-induced grandpaternal traits in grandson's cognition, even though some of the cellular changes induced in F1 vanish in F2, and suggesting that moderate exercise training has a longer-lasting effect than previously thought, most probably mediated by a small group of microRNAs acting across generations.

Experimental Models to Study Immune Dysfunction in the Pathogenesis of Parkinson's Disease.

Parkinson's disease (PD) is a chronic, age-related, progressive multisystem disease associated with neuroinflammation and immune dysfunction. This review discusses the methodological approaches used to study the changes in central and peripheral immunity in PD, the advantages and limitations of the techniques, and their applicability to humans. Although a single animal model cannot replicate all pathological features of the human disease, neuroinflammation is present in most animal models of PD and plays a critical role in understanding the involvement of the immune system (IS) in the pathogenesis of PD. The IS and its interactions with different cell types in the central nervous system (CNS) play an important role in the pathogenesis of PD. Even though culture models do not fully reflect the complexity of disease progression, they are limited in their ability to mimic long-term effects and need validation through in vivo studies. They are an indispensable tool for understanding the interplay between the IS and the pathogenesis of this disease. Understanding the immune-mediated mechanisms may lead to potential therapeutic targets for the treatment of PD. We believe that the development of methodological guidelines for experiments with animal models and PD patients is crucial to ensure the validity and consistency of the results.

Altered Cortical Palmitoylation Induces Widespread Molecular Disturbances in Parkinson's Disease.

The relationship between Parkinson's disease (PD), the second-most common neurodegenerative disease after Alzheimer's disease, and palmitoylation, a post-translational lipid modification, is not well understood. In this study, to better understand the role of protein palmitoylation in PD and the pathways altered in this disease, we analyzed the differential palmitoyl proteome (palmitome) in the cerebral cortex of PD patients compared to controls (n = 4 per group). Data-mining of the cortical palmitome from PD patients and controls allowed us to: (i) detect a set of 150 proteins with altered palmitoylation in PD subjects in comparison with controls; (ii) describe the biological pathways and targets predicted to be altered by these palmitoylation changes; and (iii) depict the overlap between the differential palmitome identified in our study with protein interactomes of the PD-linked proteins α-synuclein, LRRK2, DJ-1, PINK1, GBA and UCHL1. In summary, we partially characterized the altered palmitome in the cortex of PD patients, which is predicted to impact cytoskeleton, mitochondrial and fibrinogen functions, as well as cell survival. Our study suggests that protein palmitoylation could have a role in the pathophysiology of PD, and that comprehensive palmitoyl-proteomics offers a powerful approach for elucidating novel cellular pathways modulated in this neurodegenerative disease.

Acute Colon Inflammation Triggers Primary Motor Cortex Glial Activation, Neuroinflammation, Neuronal Hyperexcitability, and Motor Coordination Deficits.

Neuroinflammation underlies neurodegenerative diseases. Herein, we test whether acute colon inflammation activates microglia and astrocytes, induces neuroinflammation, disturbs neuron intrinsic electrical properties in the primary motor cortex, and alters motor behaviors. We used a rat model of acute colon inflammation induced by dextran sulfate sodium. Inflammatory mediators and microglial activation were assessed in the primary motor cortex by PCR and immunofluorescence assays. Electrophysiological properties of the motor cortex neurons were determined by whole-cell patch-clamp recordings. Motor behaviors were examined using open-field and rotarod tests. We show that the primary motor cortex of rats with acute colon inflammation exhibited microglial and astrocyte activation and increased mRNA abundance of interleukin-6, tumor necrosis factor-alpha, and both inducible and neuronal nitric oxide synthases. These changes were accompanied by a reduction in resting membrane potential and rheobase and increased input resistance and action potential frequency, indicating motor neuron hyperexcitability. In addition, locomotion and motor coordination were impaired. In conclusion, acute colon inflammation induces motor cortex microglial and astrocyte activation and inflammation, which led to neurons' hyperexcitability and reduced motor coordination performance. The described disturbances resembled some of the early features found in amyotrophic lateral sclerosis patients and animal models, suggesting that colon inflammation might be a risk factor for developing this disease.

Curcumin and curcumoids: hepatoprotection or hepatotoxicity?

Curcumin (Curcuma longa) and curcumin analogues are plant-based drugs used because of their possible antioxidant and anti-inflammatory. Clinical data on the efficacy of curcumin as a hepatoprotectant are limited, with growing concern for formulations that may potentially increase curcumin hepatotoxicity.

Association between Apoε4 allele and cardiometabolic and social risk factors with cognitive impairment in elderly population from Bogota / Associação entre o alelo Apoε4 fatores de risco cardiometabólicos e sociais com prejuízo cognitivo em idosos de Bogotá

ABSTRACT Being an ϵ4 carrier in the Apoϵ gene has been suggested as a modifying factor for the interaction between cardio-metabolic, social risk factors, and the development of cognitive impairment. Objective: The main objective of this study was to assess the existence of such interaction in a sample of Bogota's elderly population. Methods: A cross-sectional study was conducted with 1,263 subjects older than 50 years. Each participant was diagnosed by consensus, after neuropsychological and neuropsychiatric evaluations, under a diagnosis of normal cognition, mild cognitive impairment (MCI) according to Petersen's criteria, or dementia according to DSM-IV criteria. Apoϵ was typified and an analysis of MoCA test was performed in each group carrying or not ϵ4 allele. Results: Our study showed that 75% were women with a median age of 68 years (interquartile range 62-74 years) and a median schooling for 6 years (interquartile range 4-12 years). Dementia was related to low education level of ≤5 years OR=11.20 (95%CI 4.99-25.12), high blood pressure (HBP) OR=1.45 (95%CI 1.03-2.05), and age over 70 years OR=7.68 (95%CI 3.49-16.90), independently of being or not an ϵ4 allele carrier. Diabetic subjects with dementia carrying ϵ4 allele showed a tendency to exhibit lower scores on the MoCA test, when compared with noncarriers' diabetic subjects with dementia. Conclusions: The presence of ϵ4 allele does not modify the relationship between cognitive impairment and the different cardio-metabolic and social risk factors, except in diabetic subjects ϵ4 carriers with dementia who showed a tendency to exhibit lower scores of the MoCA test, when compared with noncarriers' diabetic subjects with dementia.

RESUMO Ser um portador ϵ4 no gene Apoϵ tem sido sugerido como um fator modificador da interação entre fatores cardiometabólicos, de risco social e o desenvolvimento de comprometimento cognitivo. Objetivo: O objetivo principal deste trabalho é avaliar a existência de tal interação em uma amostra da população idosa de Bogotá. Métodos: Um estudo transversal foi realizado com 1.263 indivíduos com mais de 50 anos. Cada participante foi diagnosticado por consenso após avaliações neuropsicológicas e neuropsiquiátricas, sob um diagnóstico de cognição normal, comprometimento cognitivo leve de acordo com os critérios de Petersen ou demência de acordo com os critérios do Manual Diagnóstico e Estatístico de Trastornos Mentais (DSM-IV). Apoϵ4 foi tipificada e uma análise do Montréal Cognitive Assessment Test (teste de MoCA) foi realizada em cada grupo portador ou não do alelo ϵ4. Resultados: Nosso estudo mostrou que 75% eram mulheres com idade mediana de 68 anos (intervalo interquartil 62 a 74 anos) e escolaridade mediana de seis anos (intervalo interquartil 4 a 12 anos). A demência estava relacionada ao baixo nível de escolaridade ≤5 anos Odds Ratio (OR)=11,20 (intervalo de confiança — IC95% 4,99-25,12), pressão alta OR=1,45 (IC95% 1,03-2,05) e idade acima de 70 anos OR=7,68 (IC95% 3,49-16,90), independentemente de ser ou não portador do alelo ϵ4. Indivíduos diabéticos com demência portadores do alelo ϵ4 mostraram tendência de exibir pontuações mais baixas no teste MoCA quando comparados com indivíduos diabéticos com demência não portadores do alelo ϵ4. Conclusões: A presença do alelo ϵ4 não modifica a relação entre o comprometimento cognitivo e os diferentes fatores de risco cardiometabólico e social, exceto em diabéticos portadores de ϵ4 com demência, que exibiram tendência a apresentar menores escores no teste MoCA quando comparados com indivíduos diabéticos com demência não portadores do alelo ϵ4.

The Role of Smad2 in Adult Neuroplasticity as Seen through Hippocampal-Dependent Spatial Learning/Memory and Neurogenesis.

Adult neural plasticity is an important and intriguing phenomenon in the brain, and adult hippocampal neurogenesis is directly involved in modulating neural plasticity by mechanisms that are only partially understood. We have performed gain-of-function and loss-of-function experiments to study Smad2, a transcription factor selected from genes that are demethylated after exercise through the analysis of an array of physical activity-induced factors, and their corresponding gene expression, and an efficient inducer of plasticity. In these studies, changes in cell number and morphology were analyzed in the hippocampal dentate gyrus (cell proliferation and survival, including regional distribution, and structural maturation/differentiation, including arborization, dendritic spines, and neurotransmitter-specific vesicles) of sedentary male mice, after evaluation in a battery of behavioral tests. As a result, we reveal a role for Smad2 in the balance of proliferation versus maturation of differentiating immature cells (Smad2 silencing increases both the proliferation and survival of cycling cells in the dentate granule cell layer), and in the plasticity of both newborn and mature neurons in mice (by decreasing dendritic arborization and dendritic spine number). Moreover, Smad2 silencing specifically compromises spatial learning in mice (through impairments of spatial tasks acquisition both in long-term learning and working memory). These data suggest that Smad2 participates in adult neural plasticity by influencing the proliferation and maturation of dentate gyrus neurons.SIGNIFICANCE STATEMENT Smad2 is one of the main components of the transforming growth factor-ß (TGF-ß) pathway. The commitment of cell fate in the nervous system is tightly coordinated by SMAD2 signaling, as are further differentiation steps (e.g., dendrite and axon growth, myelination, and synapse formation). However, there are no studies that have directly evaluated the role of Smad2 gene in hippocampus of adult animals. Modulation of these parameters in the adult hippocampus can affect hippocampal-dependent behaviors, which may shed light on the mechanisms that regulate adult neurogenesis and behavior. We demonstrate here a role for Smad2 in the maturation of differentiating immature cells and in the plasticity of mature neurons. Moreover, Smad2 silencing specifically compromises the spatial learning abilities of adult male mice.

Association between Apoϵ4 allele and cardiometabolic and social risk factors with cognitive impairment in elderly population from Bogota.

Being an ϵ4 carrier in the Apoϵ gene has been suggested as a modifying factor for the interaction between cardio-metabolic, social risk factors, and the development of cognitive impairment. Objective: The main objective of this study was to assess the existence of such interaction in a sample of Bogota's elderly population. Methods: A cross-sectional study was conducted with 1,263 subjects older than 50 years. Each participant was diagnosed by consensus, after neuropsychological and neuropsychiatric evaluations, under a diagnosis of normal cognition, mild cognitive impairment (MCI) according to Petersen's criteria, or dementia according to DSM-IV criteria. Apoϵ was typified and an analysis of MoCA test was performed in each group carrying or not ϵ4 allele. Results: Our study showed that 75% were women with a median age of 68 years (interquartile range 62-74 years) and a median schooling for 6 years (interquartile range 4-12 years). Dementia was related to low education level of ≤5 years OR=11.20 (95%CI 4.99-25.12), high blood pressure (HBP) OR=1.45 (95%CI 1.03-2.05), and age over 70 years OR=7.68 (95%CI 3.49-16.90), independently of being or not an ϵ4 allele carrier. Diabetic subjects with dementia carrying ϵ4 allele showed a tendency to exhibit lower scores on the MoCA test, when compared with noncarriers' diabetic subjects with dementia. Conclusions: The presence of ϵ4 allele does not modify the relationship between cognitive impairment and the different cardio-metabolic and social risk factors, except in diabetic subjects ϵ4 carriers with dementia who showed a tendency to exhibit lower scores of the MoCA test, when compared with noncarriers' diabetic subjects with dementia.

Ser um portador ϵ4 no gene Apoϵ tem sido sugerido como um fator modificador da interação entre fatores cardiometabólicos, de risco social e o desenvolvimento de comprometimento cognitivo. Objetivo: O objetivo principal deste trabalho é avaliar a existência de tal interação em uma amostra da população idosa de Bogotá. Métodos: Um estudo transversal foi realizado com 1.263 indivíduos com mais de 50 anos. Cada participante foi diagnosticado por consenso após avaliações neuropsicológicas e neuropsiquiátricas, sob um diagnóstico de cognição normal, comprometimento cognitivo leve de acordo com os critérios de Petersen ou demência de acordo com os critérios do Manual Diagnóstico e Estatístico de Trastornos Mentais (DSM-IV). Apoϵ4 foi tipificada e uma análise do Montréal Cognitive Assessment Test (teste de MoCA) foi realizada em cada grupo portador ou não do alelo ϵ4. Resultados: Nosso estudo mostrou que 75% eram mulheres com idade mediana de 68 anos (intervalo interquartil 62 a 74 anos) e escolaridade mediana de seis anos (intervalo interquartil 4 a 12 anos). A demência estava relacionada ao baixo nível de escolaridade ≤5 anos Odds Ratio (OR)=11,20 (intervalo de confiança ­ IC95% 4,99­25,12), pressão alta OR=1,45 (IC95% 1,03­2,05) e idade acima de 70 anos OR=7,68 (IC95% 3,49­16,90), independentemente de ser ou não portador do alelo ϵ4. Indivíduos diabéticos com demência portadores do alelo ϵ4 mostraram tendência de exibir pontuações mais baixas no teste MoCA quando comparados com indivíduos diabéticos com demência não portadores do alelo ϵ4. Conclusões: A presença do alelo ϵ4 não modifica a relação entre o comprometimento cognitivo e os diferentes fatores de risco cardiometabólico e social, exceto em diabéticos portadores de ϵ4 com demência, que exibiram tendência a apresentar menores escores no teste MoCA quando comparados com indivíduos diabéticos com demência não portadores do alelo ϵ4.

To Become or Not to Become Tumorigenic: Subventricular Zone Versus Hippocampal Neural Stem Cells.

Neural stem cells (NSCs) persist in the adult mammalian brain in two neurogenic regions: the subventricular zone lining the lateral ventricles and the dentate gyrus of the hippocampus. Compelling evidence suggests that NSCs of the subventricular zone could be the cell type of origin of glioblastoma, the most devastating brain tumor. Studies in glioblastoma patients revealed that NSCs of the tumor-free subventricular zone, harbor cancer-driver mutations that were found in the tumor cells but were not present in normal cortical tissue. Endogenous mutagenesis can also take place in hippocampal NSCs. However, to date, no conclusive studies have linked hippocampal mutations with glioblastoma development. In addition, glioblastoma cells often invade or are closely located to the subventricular zone, whereas they do not tend to infiltrate into the hippocampus. In this review we will analyze possible causes by which subventricular zone NSCs might be more susceptible to malignant transformation than their hippocampal counterparts. Cellular and molecular differences between the two neurogenic niches, as well as genotypic and phenotypic characteristics of their respective NSCs will be discussed regarding why the cell type originating glioblastoma brain tumors has been linked mainly to subventricular zone, but not to hippocampal NSCs.

Intergenerational transmission of the positive effects of physical exercise on brain and cognition.

Physical exercise has positive effects on cognition, but very little is known about the inheritance of these effects to sedentary offspring and the mechanisms involved. Here, we use a patrilineal design in mice to test the transmission of effects from the same father (before or after training) and from different fathers to compare sedentary- and runner-father progenies. Behavioral, stereological, and whole-genome sequence analyses reveal that paternal cognition improvement is inherited by the offspring, along with increased adult neurogenesis, greater mitochondrial citrate synthase activity, and modulation of the adult hippocampal gene expression profile. These results demonstrate the inheritance of exercise-induced cognition enhancement through the germline, pointing to paternal physical activity as a direct factor driving offspring's brain physiology and cognitive behavior.

Noggin rescues age-related stem cell loss in the brain of senescent mice with neurodegenerative pathology.

Increasing age is the greatest known risk factor for the sporadic late-onset forms of neurodegenerative disorders such as Alzheimer's disease (AD). One of the brain regions most severely affected in AD is the hippocampus, a privileged structure that contains adult neural stem cells (NSCs) with neurogenic capacity. Hippocampal neurogenesis decreases during aging and the decrease is exacerbated in AD, but the mechanistic causes underlying this progressive decline remain largely unexplored. We here investigated the effect of age on NSCs and neurogenesis by analyzing the senescence accelerated mouse prone 8 (SAMP8) strain, a nontransgenic short-lived strain that spontaneously develops a pathological profile similar to that of AD and that has been employed as a model system to study the transition from healthy aging to neurodegeneration. We show that SAMP8 mice display an accelerated loss of the NSC pool that coincides with an aberrant rise in BMP6 protein, enhanced canonical BMP signaling, and increased astroglial differentiation. In vitro assays demonstrate that BMP6 severely impairs NSC expansion and promotes NSC differentiation into postmitotic astrocytes. Blocking the dysregulation of the BMP pathway and its progliogenic effect in vivo by intracranial delivery of the antagonist Noggin restores hippocampal NSC numbers, neurogenesis, and behavior in SAMP8 mice. Thus, manipulating the local microenvironment of the NSC pool counteracts hippocampal dysfunction in pathological aging. Our results shed light on interventions that may allow taking advantage of the brain's natural plastic capacity to enhance cognitive function in late adulthood and in chronic neurodegenerative diseases such as AD.

Mild cognitive impairment (MCI) and dementia in a sample of adults in the city of Bogotá.

The low prevalence of dementia described in communities is likely due to the low sensitivity of screening tests and an absence of evaluation by specialists. OBJECTIVE: To estimate the prevalence of mild cognitive impairment (MCI) and dementia in adults older than 50 years. METHODS: A two-phase, cross-sectional study was conducted by specialists to evaluate cognition and associated demographic risk factors in 1,235 independent community-dwelling adults from Bogotá. In Phase I, screening was performed using the MMSE and MoCA tests. In Phase II, after application of a comprehensive neuropsychological battery with neurologic and psychiatric evaluations, a cognitive diagnosis was established by consensus. RESULTS: The prevalence found for MCI was 34% and for dementia was 23%. MCI was associated with incomplete high school, OR=1.74 (95%CI=1.23-2.45), and with an age of 70-79 years, OR=1.93 (95%CI=1.47-2.53). A total of 73% of MCI cases were amnestic. Dementia was associated with incomplete primary education, OR=8.98 (95%CI=5.56-14.54), complete primary education, OR=6.23 (95%CI=3.70-10.47), and age older than eighty years, OR=3.49 (95%CI=2.23-5.44). CONCLUSION: The prevalence of dementia found was greater than the rates reported in previous studies. Low educational level was the main risk factor for cognitive impairment and should be considered in strategic planning for the local health system.

A baixa prevalência de demência relatada em comunidades deve ser devida ao emprego de testes de rastreio de baixa sensibilidade e à falta da avaliação por especialistas. OBJETIVO: Estimar a prevalência de comprometimento cognitivo leve (CCL) e demência em adultos com idade superior a 50 anos. MÉTODOS: Um estudo transversal de duas fases realizado por especialistas, avaliando a cognição e os fatores de risco demográficos associados, com 1.235 adultos autônomos da comunidade em Bogotá. Em uma Fase I, foram realizados os testes de rastreio MEEM e MoCA. Na Fase II, após uma ampla bateria neuropsicológica com avaliações neurológicas e psiquiátricas, foi estabelecido um diagnóstico cognitivo por consenso. RESULTADOS: A prevalência encontrada de CCL foi de 34% e de demência, de 23%. CCL foi associado a ensino médio incompleto, OR=1,74 (IC 95%=1,23-2,45) e idade entre 70-79 anos, OR=1,93 (IC 95%=1,47-2,53). Entre os casos de CCL, 73% eram amnésticos. A demência foi associada a ensino fundamental incompleto, OR=8,98 (IC 95%=5,56-14,54), ensino fundamental completo, OR=6,23 (IC 95%=3,70-10,47) e idade superior a oitenta anos, OR=3,49 (IC 95%=2,23-5,44). CONCLUSÃO: A prevalência de demência encontrada é maior do que a relatada em estudos prévios. O baixo nível educacional foi o principal fator de risco para declínio cognitivo e deve ser considerado no planejamento estratégico do nosso sistema de saúde.

Mild cognitive impairment (MCI) and dementia in a sample of adults in the city of Bogotá / Comprometimento cognitivo leve (CCL) e demência em uma amostra de adultos na cidade de bogotá

ABSTRACT The low prevalence of dementia described in communities is likely due to the low sensitivity of screening tests and an absence of evaluation by specialists. OBJECTIVE: To estimate the prevalence of mild cognitive impairment (MCI) and dementia in adults older than 50 years. METHODS: A two-phase, cross-sectional study was conducted by specialists to evaluate cognition and associated demographic risk factors in 1,235 independent community-dwelling adults from Bogotá. In Phase I, screening was performed using the MMSE and MoCA tests. In Phase II, after application of a comprehensive neuropsychological battery with neurologic and psychiatric evaluations, a cognitive diagnosis was established by consensus. RESULTS: The prevalence found for MCI was 34% and for dementia was 23%. MCI was associated with incomplete high school, OR=1.74 (95%CI=1.23-2.45), and with an age of 70-79 years, OR=1.93 (95%CI=1.47-2.53). A total of 73% of MCI cases were amnestic. Dementia was associated with incomplete primary education, OR=8.98 (95%CI=5.56-14.54), complete primary education, OR=6.23 (95%CI=3.70-10.47), and age older than eighty years, OR=3.49 (95%CI=2.23-5.44). CONCLUSION: The prevalence of dementia found was greater than the rates reported in previous studies. Low educational level was the main risk factor for cognitive impairment and should be considered in strategic planning for the local health system.

RESUMO A baixa prevalência de demência relatada em comunidades deve ser devida ao emprego de testes de rastreio de baixa sensibilidade e à falta da avaliação por especialistas. OBJETIVO: Estimar a prevalência de comprometimento cognitivo leve (CCL) e demência em adultos com idade superior a 50 anos. MÉTODOS: Um estudo transversal de duas fases realizado por especialistas, avaliando a cognição e os fatores de risco demográficos associados, com 1.235 adultos autônomos da comunidade em Bogotá. Em uma Fase I, foram realizados os testes de rastreio MEEM e MoCA. Na Fase II, após uma ampla bateria neuropsicológica com avaliações neurológicas e psiquiátricas, foi estabelecido um diagnóstico cognitivo por consenso. RESULTADOS: A prevalência encontrada de CCL foi de 34% e de demência, de 23%. CCL foi associado a ensino médio incompleto, OR=1,74 (IC 95%=1,23-2,45) e idade entre 70-79 anos, OR=1,93 (IC 95%=1,47-2,53). Entre os casos de CCL, 73% eram amnésticos. A demência foi associada a ensino fundamental incompleto, OR=8,98 (IC 95%=5,56-14,54), ensino fundamental completo, OR=6,23 (IC 95%=3,70-10,47) e idade superior a oitenta anos, OR=3,49 (IC 95%=2,23-5,44). CONCLUSÃO: A prevalência de demência encontrada é maior do que a relatada em estudos prévios. O baixo nível educacional foi o principal fator de risco para declínio cognitivo e deve ser considerado no planejamento estratégico do nosso sistema de saúde.

Neuronal tetraploidization in the cerebral cortex correlates with reduced cognition in mice and precedes and recapitulates Alzheimer's-associated neuropathology.

A controversy exists as to whether de novo-generated neuronal tetraploidy (dnNT) occurs in Alzheimer's disease. In addition, the presence of age-associated dnNT in the normal brain remains unexplored. Here we show that age-associated dnNT occurs in both superficial and deep layers of the cerebral cortex of adult mice, a process that is blocked in the absence of E2F1, a known regulator of cell cycle progression. This blockage correlates with improved cognition despite compromised neurogenesis in the adult hippocampus was confirmed in mice lacking the E2f1 gene. We also show that the human cerebral cortex contains tetraploid neurons. In normal humans, age-associated dnNT specifically occurs in the entorhinal cortex whereas, in Alzheimer, dnNT also affects association cortices prior to neurofibrillary tangle formation. Alzheimer-associated dnNT is likely potentiated by altered amyloid precursor protein (APP) processing as it is enhanced in the cerebral cortex of young APPswe/PS1deltaE9 mice, long before the first amyloid plaques are visible in their brains. In contrast to age-associated dnNT, enhanced dnNT in APPswe/PS1deltaE9 mice mostly affects the superficial cortical layers. The correlation of dnNT with reduced cognition in mice and its spatiotemporal course, preceding and recapitulating Alzheimer-associated neuropathology, makes this process a potential target for intervention in Alzheimer's disease.

Can Exercise Make You Smarter, Happier, and Have More Neurons? A Hormetic Perspective.

Exercise can make you smarter, happier and have more neurons depending on the dose (intensity) of the training program. It is well recognized that exercise protocols induce both positive and negative effects depending on the intensity of the exercise, among other key factors, a process described as a hormetic-like biphasic dose-response. However, no evidences have been reported till very recently about the biphasic response of some of the potential mediators of the exercise-induced actions. This hypothesis and theory will focus on the adult hippocampal neurogenesis (AHN) as a putative physical substrate for hormesis responses to exercise in the context of exercise-induced actions on cognition and mood, and on the molecular pathways which might potentially be mediating these actions.

Postnatal proteasome inhibition induces neurodegeneration and cognitive deficiencies in adult mice: a new model of neurodevelopment syndrome.

Defects in the ubiquitin-proteasome system have been related to aging and the development of neurodegenerative disease, although the effects of deficient proteasome activity during early postnatal development are poorly understood. Accordingly, we have assessed how proteasome dysfunction during early postnatal development, induced by administering proteasome inhibitors daily during the first 10 days of life, affects the behaviour of adult mice. We found that this regime of exposure to the proteasome inhibitors MG132 or lactacystin did not produce significant behavioural or morphological changes in the first 15 days of life. However, towards the end of the treatment with proteasome inhibitors, there was a loss of mitochondrial markers and activity, and an increase in DNA oxidation. On reaching adulthood, the memory of mice that were injected with proteasome inhibitors postnatally was impaired in hippocampal and amygdala-dependent tasks, and they suffered motor dysfunction and imbalance. These behavioural deficiencies were correlated with neuronal loss in the hippocampus, amygdala and brainstem, and with diminished adult neurogenesis. Accordingly, impairing proteasome activity at early postnatal ages appears to cause morphological and behavioural alterations in adult mice that resemble those associated with certain neurodegenerative diseases and/or syndromes of mental retardation.

The A-current modulates learning via NMDA receptors containing the NR2B subunit.

Synaptic plasticity involves short- and long-term events, although the molecular mechanisms that underlie these processes are not fully understood. The transient A-type K(+) current (I(A)) controls the excitability of the dendrites from CA1 pyramidal neurons by regulating the back-propagation of action potentials and shaping synaptic input. Here, we have studied how decreases in I(A) affect cognitive processes and synaptic plasticity. Using wild-type mice treated with 4-AP, an I(A) inhibitor, and mice lacking the DREAM protein, a transcriptional repressor and modulator of the I(A), we demonstrate that impairment of I(A) decreases the stimulation threshold for learning and the induction of early-LTP. Hippocampal electrical recordings in both models revealed alterations in basal electrical oscillatory properties toward low-theta frequencies. In addition, we demonstrated that the facilitated learning induced by decreased I(A) requires the activation of NMDA receptors containing the NR2B subunit. Together, these findings point to a balance between the I(A) and the activity of NR2B-containing NMDA receptors in the regulation of learning.

The M-current inhibitor XE991 decreases the stimulation threshold for long-term synaptic plasticity in healthy mice and in models of cognitive disease.

Aging, mental retardation, number of psychiatric and neurological disorders are all associated with learning and memory impairments. As the underlying causes of such conditions are very heterogeneous, manipulations that can enhance learning and memory in mice under different circumstances might be able to overcome the cognitive deficits in patients. The M-current regulates neuronal excitability and action potential firing, suggesting that its inhibition may increase cognitive capacities. We demonstrate that XE991, a specific M-current blocker, enhances learning and memory in healthy mice. This effect may be achieved by altering basal hippocampal synaptic activity and by diminishing the stimulation threshold for long-term changes in synaptic efficacy and learning-related gene expression. We also show that training sessions regulate the M-current by transiently decreasing the levels of KCNQ/Kv7.3 protein, a pivotal subunit for the M-current. Furthermore, we found that XE991 can revert the cognitive impairment associated with acetylcholine depletion and the neurodegeneration induced by kainic acid. Together, these results show that inhibition of the M-current as a general strategy may be useful to enhance cognitive capacities in healthy and aging individuals, as well as in those with neurodegenerative diseases.