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1.
Nutr Neurosci ; : 1-13, 2024 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-38970804

RESUMO

Dementia is a debilitating condition with a disproportionate impact on women. While sex differences in longevity contribute to the disparity, the role of the female sex as a biological variable in disease progression is not yet fully elucidated. Metabolic dysfunctions are drivers of dementia etiology, and cardiometabolic diseases are among the most influential modifiable risk factors. Pregnancy is a time of enhanced vulnerability for metabolic disorders. Many dementia risk factors, such as hypertension or blood glucose dysregulation, often emerge for the first time in pregnancy. While such cardiometabolic complications in pregnancy pose a risk to the health trajectory of a woman, increasing her odds of developing type 2 diabetes or chronic hypertension, it is not fully understood how this relates to her risk for dementia. Furthermore, structural and functional changes in the maternal brain have been reported during pregnancy suggesting it is a time of neuroplasticity for the mother. Therefore, pregnancy may be a window of opportunity to optimize metabolic health and support the maternal brain. Healthy dietary patterns are known to reduce the risk of cardiometabolic diseases and have been linked to dementia prevention, yet interventions targeting cognitive function in late life have largely been unsuccessful. Earlier interventions are needed to address the underlying metabolic dysfunctions and potentially reduce the risk of dementia, and pregnancy offers an ideal opportunity to intervene. This review discusses current evidence regarding maternal brain health and the potential window of opportunity in pregnancy to use diet to address neurological health disparities for women.

2.
Neuroimage ; 187: 209-225, 2019 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-29793062

RESUMO

Brain aging and associated neurodegeneration constitute a major societal challenge as well as one for the neuroimaging community. A full understanding of the physiological mechanisms underlying neurodegeneration still eludes medical researchers, fuelling the development of in vivo neuroimaging markers. Hence it is increasingly recognized that our understanding of neurodegenerative processes likely will depend upon the available information provided by imaging techniques. At the same time, the imaging techniques are often developed in response to the desire to observe certain physiological processes. In this context, functional MRI (fMRI), which has for decades provided information on neuronal activity, has evolved into a large family of techniques well suited for in vivo observations of brain physiology. Given the rapid technical advances in fMRI in recent years, this review aims to summarize the physiological basis of fMRI observations in healthy aging as well as in age-related neurodegeneration. This review focuses on in-vivo human brain imaging studies in this review and on disease features that can be imaged using fMRI methods. In addition to providing detailed literature summaries, this review also discusses future directions in the study of brain physiology using fMRI in the clinical setting.


Assuntos
Envelhecimento/fisiologia , Mapeamento Encefálico , Encéfalo/fisiologia , Imageamento por Ressonância Magnética , Doenças Neurodegenerativas/diagnóstico por imagem , Doenças Neurodegenerativas/fisiopatologia , Biomarcadores , Barreira Hematoencefálica/diagnóstico por imagem , Barreira Hematoencefálica/metabolismo , Encéfalo/diagnóstico por imagem , Encéfalo/fisiopatologia , Humanos , Acoplamento Neurovascular
3.
Am J Epidemiol ; 188(4): 656-663, 2019 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-30657841

RESUMO

Not much is known about brain structural change in younger populations and minorities. The cross-sectional relationship between depressive symptomatology and racial discrimination with structural measures of brain tissue volume was investigated using magnetic resonance images of 710 participants in the Coronary Artery Risk Development in Young Adults CARDIA Study in 2010. Those reporting depressive symptoms and racial discrimination had lower total brain matter volume compared with those who reported neither (-8.8 mL, 95% confidence interval (CI): -16.4, -1.2), those who reported depressive symptoms only (-10.9 mL, 95% CI: -20.4, -1.4), and those who reported racial discrimination only (-8.6 mL, 95% CI: -16.5, -0.8). Results were similar for total normal white matter. There were 103% higher odds (odds ratio = 2.03, 95% CI: 1.32, 3.14) of being in the highest quartile of white matter hyperintensities in those with depressive symptoms only compared to those without. Although tests for interaction by race were not statistically significant, sensitivity analyses stratified by race revealed inverse associations with total brain matter and total white matter volumes only among black participants with combined depressive symptomatology and experience of racial discrimination, and positive associations only among white participants with depressive symptoms with presence of white matter hyperintensities, suggesting future studies may focus on race.


Assuntos
Encéfalo/diagnóstico por imagem , Depressão/diagnóstico por imagem , Depressão/patologia , Imageamento por Ressonância Magnética/estatística & dados numéricos , Racismo/psicologia , Adulto , Negro ou Afro-Americano/psicologia , Encéfalo/patologia , Estudos Transversais , Depressão/etnologia , Feminino , Humanos , Masculino , Razão de Chances , Tamanho do Órgão , Fatores de Risco , População Branca/psicologia , Adulto Jovem
4.
J Biol Chem ; 289(36): 25166-76, 2014 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-25059665

RESUMO

The glucose-regulated protein 78 (GRP78) is a plasminogen (Pg) receptor on the cell surface. In this study, we demonstrate that GRP78 also binds the tissue-type plasminogen activator (t-PA), which results in a decrease in K(m) and an increase in the V(max) for both its amidolytic activity and activation of its substrate, Pg. This results in accelerated Pg activation when GRP78, t-PA, and Pg are bound together. The increase in t-PA activity is the result of a mechanism involving a t-PA lysine-dependent binding site in the GRP78 amino acid sequence (98)LIGRTWNDPSVQQDIKFL(115). We found that GRP78 is expressed on the surface of neuroblastoma SK-N-SH cells where it is co-localized with the voltage-dependent anion channel (VDAC), which is also a t-PA-binding protein in these cells. We demonstrate that both Pg and t-PA serve as a bridge between GRP78 and VDAC bringing them together to facilitate Pg activation. t-PA induces SK-N-SH cell proliferation via binding to GRP78 on the cell surface. Furthermore, Pg binding to the COOH-terminal region of GRP78 stimulates cell proliferation via its microplasminogen domain. This study confirms previous findings from our laboratory showing that GRP78 acts as a growth factor-like receptor and that its association with t-PA, Pg, and VDAC on the cell surface may be part of a system controlling cell growth.


Assuntos
Proliferação de Células , Proteínas de Choque Térmico/metabolismo , Plasminogênio/metabolismo , Ativador de Plasminogênio Tecidual/metabolismo , Amidoidrolases/metabolismo , Sequência de Aminoácidos , Linhagem Celular Tumoral , Membrana Celular/metabolismo , Chaperona BiP do Retículo Endoplasmático , Ativação Enzimática , Humanos , Immunoblotting , Cinética , Microscopia de Fluorescência , Dados de Sequência Molecular , Neuroblastoma/metabolismo , Neuroblastoma/patologia , Ligação Proteica , Especificidade por Substrato , Canais de Ânion Dependentes de Voltagem/metabolismo
5.
Neurooncol Adv ; 6(1): vdad160, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38221979

RESUMO

Chronic oxidative stress plays a critical role in the development of brain malignancies due to the high rate of brain oxygen utilization and concomitant production of reactive oxygen species. The nuclear factor-erythroid-2-related factor 2 (NRF2), a master regulator of antioxidant signaling, is a key factor in regulating brain physiology and the development of age-related neurodegenerative diseases. Also, NRF2 is known to exert a protective antioxidant effect against the onset of oxidative stress-induced diseases, including cancer, along with its pro-oncogenic activities through regulating various signaling pathways and downstream target genes. In glioblastoma (GB), grade 4 glioma, tumor resistance, and recurrence are caused by the glioblastoma stem cell population constituting a small bulk of the tumor core. The persistence and self-renewal capacity of these cell populations is enhanced by NRF2 expression in GB tissues. This review outlines NRF2's dual involvement in cancer and highlights its regulatory role in human brain physiology and diseases, in addition to the development of primary brain tumors and therapeutic potential, with a focus on GB.

6.
Neuroimage ; 81: 8-14, 2013 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-23664942

RESUMO

UNLABELLED: Traditional interpretation of rCBF SPECT data is of a qualitative nature and is dependent on the observer's understanding of the normal distribution of the tracer. The use of a normal database in quantitative regional analysis facilitates the detection of functional abnormality in individual and group studies by accounting for inter-subject variability. The ability to simulate realistic images would allow various important areas related to the use of normal databases to be studied. These include the optimisation of the detection of abnormal blood flow and the portability of normal databases between gamma camera systems. To investigate this further we have constructed a hardware phantom and scanned various configurations of radioactive brain patterns and simulated skull configurations. METHODS: A subresolution sandwich phantom was constructed with a simulated skull which was assembled using a high-resolution segmented MR scan printed with a (99m)TcO4 - mixture and scanned using a double-headed gamma camera with parallel-hole collimators. Various different grey-to-white matter (GM:WM) ratios and aluminium simulated skull configurations were used. A single difference measure between the phantom data and a control database mean image was used for optimisation. The realism of phantom data was assessed using statistical parametric mapping (SPM) and ROI analysis. RESULTS: Optimisation was achieved with a range of WM:GM ratios from 1.9 to 2.4:1 with various simulated skull configurations. CONCLUSION: The ability to simulate realistic HMPAO SPECT scans has been demonstrated using a subresolution sandwich phantom. Further work, involving scanning the optimised phantom on different gamma camera systems and comparison with camera-specific normal databases should further refine the phantom configuration.


Assuntos
Mapeamento Encefálico/métodos , Imagens de Fantasmas , Tomografia Computadorizada de Emissão de Fóton Único/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Encéfalo/diagnóstico por imagem , Encéfalo/fisiologia , Circulação Cerebrovascular/fisiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Compostos Radiofarmacêuticos , Tecnécio Tc 99m Exametazima
7.
Front Hum Neurosci ; 17: 1194714, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37850039

RESUMO

Introduction: As burnout has become a global pandemic, there is a call for improved understanding and detection of alterations in brain functions related to it. We have previously reported challenges in executive functions (EFs) in daily life, especially in metacognition, in subjects with occupational burnout, along with alterations in cardiac physiology. In the current study, we focused on the impact of burnout on brain physiology during a task requiring EF. Methods: Fifty-four volunteers filled in inventories of burnout, depression, and EF in daily life (BBI-15, BDI, and BRIEF-A). Based on the BBI-15 score, subjects were divided into burnout and non-burnout groups. Subjects performed a Go/NoGo test (Executive RT test) engaging several EFs, while their EEG was recorded. The inventory scores, cognitive performance scores, and event-related potential (N2, P3) amplitudes, latencies, and interpeak latencies (IPLs) were compared between the groups. Results: There were significant differences in the BDI and BRIEF-A scores between the groups, with more symptoms of depression and challenges in daily life in the burnout group. There were no differences in objective performance measures in the EF task between the groups. However, centroparietal P3 amplitude was larger, and while there were no differences in N2 or P3 latencies, N2-P3 IPL was longer in the Go condition in the burnout than in non-burnout group. Both ERP measures correlated significantly with burnout symptoms. A regression model from centroparietal P3 amplitude and N2-P3 IPL predicted significantly both the BBI-15 score and the BRIEF-A metacognition index. Discussion: We conclude that burnout is linked with challenges in EF in daily life and alterations in the underlying neural processes. While cognitive performance in the task was equal, electrophysiological measures differed between the groups. Prolonged N2-P3 IPL points toward slowed transition from one cognitive process to another. Increased P3 amplitude, on the other hand, reflects increased allocation of neural processing resources. This may be a compensatory mechanism, allowing for equal performance with controls. These electrophysiological measures, obtained during the EF task, show promise as brain physiology-based biomarkers of burnout, contributing to its improved and objective detection. In addition, these results indicate occupational burnout is linked with objective alterations in brain physiology.

8.
Brain Sci ; 13(7)2023 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-37508938

RESUMO

This paper delves into the intricate structure and functionality of the brain's glymphatic system, bringing forth new dimensions in its neuroscientific understanding. This paper commences by exploring the cerebrospinal fluid (CSF)-its localization, production, and pivotal role within the central nervous system, acting as a cushion and vehicle for nutrient distribution and waste elimination. We then transition into an in-depth study of the morphophysiological aspects of the glymphatic system, a recent discovery revolutionizing the perception of waste clearance from the brain, highlighting its lymphatic-like characteristics and remarkable operations. This paper subsequently emphasizes the glymphatic system's potential implications in Alzheimer's disease (AD), discussing the connection between inefficient glymphatic clearance and AD pathogenesis. This review also elucidates the intriguing interplay between the glymphatic system and the circadian rhythm, illustrating the optimal functioning of glymphatic clearance during sleep. Lastly, we underscore the hitherto underappreciated involvement of the glymphatic system in the tumoral microenvironment, potentially impacting tumor growth and progression. This comprehensive paper accentuates the glymphatic system's pivotal role in multiple domains, fostering an understanding of the brain's waste clearance mechanisms and offering avenues for further research into neuropathological conditions.

9.
J Cereb Blood Flow Metab ; 42(10): 1840-1853, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-35570730

RESUMO

Respiratory brain pulsations have recently been shown to drive electrophysiological brain activity in patients with epilepsy. Furthermore, functional neuroimaging indicates that respiratory brain pulsations have increased variability and amplitude in patients with epilepsy compared to healthy individuals. To determine whether the respiratory drive is altered in epilepsy, we compared respiratory brain pulsation synchronicity between healthy controls and patients. Whole brain fast functional magnetic resonance imaging was performed on 40 medicated patients with focal epilepsy, 20 drug-naïve patients and 102 healthy controls. Cerebrospinal fluid associated respiratory pulsations were used to generate individual whole brain respiratory synchronization maps, which were compared between groups. Finally, we analyzed the seizure frequency effect and diagnostic accuracy of the respiratory synchronization defect in epilepsy. Respiratory brain pulsations related to the verified fourth ventricle pulsations were significantly more synchronous in patients in frontal, periventricular and mid-temporal regions, while the seizure frequency correlated positively with synchronicity. The respiratory brain synchronicity had a good diagnostic accuracy (ROCAUC = 0.75) in discriminating controls from medicated patients. The elevated respiratory brain synchronicity in focal epilepsy suggests altered physiological effect of cerebrospinal fluid pulsations possibly linked to regional brain water dynamics involved with interictal brain physiology.


Assuntos
Epilepsias Parciais , Epilepsia , Encéfalo/irrigação sanguínea , Eletroencefalografia/métodos , Epilepsias Parciais/diagnóstico por imagem , Epilepsia/diagnóstico por imagem , Humanos , Imageamento por Ressonância Magnética/métodos , Convulsões , Água
10.
Geroscience ; 44(4): 1905-1923, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35648331

RESUMO

Reduced cerebrovascular response to neuronal activation is observed in patients with neurodegenerative disease. In the present study, we examined the correlation between reduced cerebrovascular response to visual activation (ΔCBFVis.Act) and subclinical cognitive deficits in a human population of mid-sixties individuals without neurodegenerative disease. Such a correlation would suggest that impaired cerebrovascular function occurs before overt neurodegenerative disease. A total of 187 subjects (age 64-67 years) of the Metropolit Danish Male Birth Cohort participated in the study. ΔCBFVis.Act was measured using arterial spin labelling (ASL) MRI. ΔCBFVis.Act correlated positively with cognitive performance in: Global cognition (p = 0.046), paired associative memory (p = 0.025), spatial recognition (p = 0.026), planning (p = 0.016), simple processing speed (p < 0.01), and with highly significant correlations with current intelligence (p < 10-5), and more complex processing speed (p < 10-3), the latter two explaining approximately 11-13% of the variance. Reduced ΔCBFVis.Act was independent of brain atrophy. Our findings suggest that inhibited cerebrovascular response to neuronal activation is an early deficit in the ageing brain and associated with subclinical cognitive deficits. Cerebrovascular dysfunction could be an early sign of a trajectory pointing towards the development of neurodegenerative disease. Future efforts should elucidate if maintenance of a healthy cerebrovascular function can protect against the development of dementia.


Assuntos
Disfunção Cognitiva , Doenças Neurodegenerativas , Humanos , Masculino , Idoso , Estimulação Luminosa , Circulação Cerebrovascular/fisiologia , Cognição
11.
Acta Biomater ; 132: 379-400, 2021 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-34157452

RESUMO

The neural circuits of the central nervous system are the regulatory pathways for feeling, motion control, learning, and memory, and their dysfunction is closely related to various neurodegenerative diseases. Despite the growing demand for the unraveling of the physiology and functional connectivity of the neural circuits, their fundamental investigation is hampered because of the inability to access the components of neural circuits and the complex microenvironment. As an alternative approach, in vitro human neural circuits show principles of in vivo human neuronal circuit function. They allow access to the cellular compartment and permit real-time monitoring of neural circuits. In this review, we summarize recent advances in reconstituted in vitro neural circuits using engineering techniques. To this end, we provide an overview of the fabrication techniques and methods for stimulation and measurement of in vitro neural circuits. Subsequently, representative examples of in vitro neural circuits are reviewed with a particular focus on the recapitulation of structures and functions observed in vivo, and we summarize their application in the study of various brain diseases. We believe that the in vitro neural circuits can help neuroscience and the neuropharmacology. STATEMENT OF SIGNIFICANCE: Despite the growing demand to unravel the physiology and functional connectivity of the neural circuits, the studies on the in vivo neural circuits are frequently limited due to the poor accessibility. Furthermore, single neuron-based analysis has an inherent limitation in that it does not reflect the full spectrum of the neural circuit physiology. As an alternative approach, in vitro engineered neural circuit models have arisen because they can recapitulate the structural and functional characteristics of in vivo neural circuits. These in vitro neural circuits allow the mimicking of dysregulation of the neural circuits, including neurodegenerative diseases and traumatic brain injury. Emerging in vitro engineered neural circuits will provide a better understanding of the (patho-)physiology of neural circuits.


Assuntos
Doenças Neurodegenerativas , Neurônios , Encéfalo , Humanos , Aprendizagem
12.
Front Neurol ; 12: 702649, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34335455

RESUMO

Left hemispatial neglect (LHSN) is a frequent and disabling condition affecting patients who suffered from traumatic brain injury (TBI). LHSN is a neuropsychological syndrome characterized clinically by difficulties in attending, responding, and consciously representing the right side of space. Despite its frequency, scientific evidence on effective treatments for this condition in TBI patients is still low. According to existing literature, we hypothesize that in TBI, LHSN is caused by an imbalance in inter-hemispheric activity due to hyperactivity of the left hemisphere, as observed in LHSN after right strokes. Thus, by inhibiting this left hyperactivity, repetitive Transcranial Magnetic Stimulation (rTMS) would have a rebalancing effect, reducing LHSN symptoms in TBI patients. We plan to test this hypothesis within a single-blind, randomized SHAM controlled trial in which TBI patients will receive inhibitory i-rTMS followed by cognitive treatment for 15 days. Neurophysiological and clinical measures will be collected before, afterward, and in the follow-up. This study will give the first empirical evidence about the efficacy of a novel approach to treating LHSN in TBI patients. Clinical Trial Registration: https://www.clinicaltrials.gov/ct2/show/NCT04573413?cond=Neglect%2C+Hemispatial&cntry=IT&city=Bologna&draw=2&rank=2, identifier: NCT04573413.

13.
Curr Aging Sci ; 14(3): 223-234, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34229598

RESUMO

AIMS: Lipoprotein (a) deposition in coronary vascular plaques and cerebral vessels is a recognized risk factor for cardiovascular disease, and research supports its role as a "repair factor" in vascular walls weakened by vitamin C deficiency. BACKGROUND: Humans depend on dietary vitamin C as an important antioxidant and as a cofactor in collagen synthesis, yet are prone to vitamin C deficiency. The brain is the one with the highest vitamin C content, owing to its high oxygen consumption and oxidative stress. It has been shown that brain aging is accompanied by accumulated oxidative damage, which can lead to memory decline and neurological diseases. OBJECTIVE: Our transgenic mouse, Gulo (-/-); Lp(a)+, presents a unique model for the study of key aspects of human metabolism with respect to a lack of internal vitamin C synthesis and the production of human lipoprotein(a). METHODS: This mouse model was used in our study to investigate the effects of prolonged intake of low and high levels of vitamin C, at different ages, on oxidative damage, cholesterol levels and lipoprotein( a) deposition in the brain. RESULT: The results show that a long-term high vitamin C intake is important in maintaining brain cholesterol homeostasis and preventing oxidative damage in Gulo(-/-);Lp(a)+ mice as they age. Moreover, we observed that the formation of brain lipoprotein(a) deposits was negatively correlated with brain level of vitamin C, thereby confirming its role as a stability factor for an impaired extracellular matrix. CONCLUSION: Our study emphasizes the critical role of vitamin C in protecting brain health as we age. Other: Our findings show that optimal vitamin C intake from early life to old age is important for brain health as it prevents oxidative stress damage and maintains cholesterol homeostasis in the brain. More importantly, the negative correlation between brain ascorbic levels and the formation of Lp(a) deposit on the choroid plexus further emphasizes the critical role of vitamin C in protecting brain health throughout the normal aging process.


Assuntos
Fatores Etários , Deficiência de Ácido Ascórbico , Ácido Ascórbico , Encéfalo/fisiologia , Lipoproteína(a)/metabolismo , Animais , Antioxidantes , Ácido Ascórbico/administração & dosagem , Humanos , Camundongos , Camundongos Transgênicos
14.
Front Mol Neurosci ; 14: 710303, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34489641

RESUMO

In the last decades, the effects of sedentary lifestyles have emerged as a critical aspect of modern society. Interestingly, recent evidence demonstrated that physical exercise plays an important role not only in maintaining peripheral health but also in the regulation of central nervous system function. Many studies have shown that physical exercise promotes the release of molecules, involved in neuronal survival, differentiation, plasticity and neurogenesis, from several peripheral organs. Thus, aerobic exercise has emerged as an intriguing tool that, on one hand, could serve as a therapeutic protocol for diseases of the nervous system, and on the other hand, could help to unravel potential molecular targets for pharmacological approaches. In the present review, we will summarize the cellular interactions that mediate the effects of physical exercise on brain health, starting from the factors released in myocytes during muscle contraction to the cellular pathways that regulate higher cognitive functions, in both health and disease.

15.
Trials ; 22(1): 24, 2021 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-33407787

RESUMO

BACKGROUND: Left hemispatial neglect (LHN) is a neuropsychological syndrome often associated with right hemispheric stroke. Patients with LHN have difficulties in attending, responding, and consciously representing the right side of space. Various rehabilitation protocols have been proposed to reduce clinical symptoms related to LHN, using cognitive treatments, or on non-invasive brain stimulation. However, evidence of their benefit is still lacking; in particular, only a few studies focused on the efficacy of combining different approaches in the same patient. METHODS: In the present study, we present the SMART ATLAS trial (Stimolazione MAgnetica Ripetitiva Transcranica nell'ATtenzione LAteralizzata dopo Stroke), a multicenter, randomized, controlled trial with pre-test (baseline), post-test, and 12 weeks follow-up assessments based on a novel rehabilitation protocol based on the combination of brain stimulation and standard cognitive treatment. In particular, we will compare the efficacy of inhibitory repetitive-transcranial magnetic stimulation (r-TMS), applied over the left intact parietal cortex of LHN patients, followed by visual scanning treatment, in comparison with a placebo stimulation (SHAM control) followed by the same visual scanning treatment, on visuospatial symptoms and neurophysiological parameters of LHN in a population of stroke patients. DISCUSSION: Our trial results may provide scientific evidence of a new, relatively low-cost rehabilitation protocol for the treatment of LHN. TRIAL REGISTRATION: ClinicalTrials.gov NCT04080999 . Registered on September 2019.


Assuntos
Transtornos da Percepção , Reabilitação do Acidente Vascular Cerebral , Acidente Vascular Cerebral , Sintomas Comportamentais , Cognição , Humanos , Estudos Multicêntricos como Assunto , Transtornos da Percepção/diagnóstico , Transtornos da Percepção/etiologia , Transtornos da Percepção/terapia , Ensaios Clínicos Controlados Aleatórios como Assunto , Acidente Vascular Cerebral/complicações , Acidente Vascular Cerebral/diagnóstico , Acidente Vascular Cerebral/terapia , Estimulação Magnética Transcraniana , Resultado do Tratamento
16.
Brain Commun ; 2(2): fcaa076, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32954328

RESUMO

Resting-state functional MRI has shown potential for detecting changes in cerebral blood oxygen level-dependent signal in patients with epilepsy, even in the absence of epileptiform activity. Furthermore, it has been suggested that coefficient of variation mapping of fast functional MRI signal may provide a powerful tool for the identification of intrinsic brain pulsations in neurological diseases such as dementia, stroke and epilepsy. In this study, we used fast functional MRI sequence (magnetic resonance encephalography) to acquire ten whole-brain images per second. We used the functional MRI data to compare physiological brain pulsations between healthy controls (n = 102) and patients with epilepsy (n = 33) and furthermore to drug-naive seizure patients (n = 9). Analyses were performed by calculating coefficient of variation and spectral power in full band and filtered sub-bands. Brain pulsations in the respiratory-related frequency sub-band (0.11-0.51 Hz) were significantly (P < 0.05) increased in patients with epilepsy, with an increase in both signal variance and power. At the individual level, over 80% of medicated and drug-naive seizure patients exhibited areas of abnormal brain signal power that correlated well with the known clinical diagnosis, while none of the controls showed signs of abnormality with the same threshold. The differences were most apparent in the basal brain structures, respiratory centres of brain stem, midbrain and temporal lobes. Notably, full-band, very low frequency (0.01-0.1 Hz) and cardiovascular (0.8-1.76 Hz) brain pulses showed no differences between groups. This study extends and confirms our previous results of abnormal fast functional MRI signal variance in epilepsy patients. Only respiratory-related brain pulsations were clearly increased with no changes in either physiological cardiorespiratory rates or head motion between the subjects. The regional alterations in brain pulsations suggest that mechanisms driving the cerebrospinal fluid homeostasis may be altered in epilepsy. Magnetic resonance encephalography has both increased sensitivity and high specificity for detecting the increased brain pulsations, particularly in times when other tools for locating epileptogenic areas remain inconclusive.

17.
J Cereb Blood Flow Metab ; 40(12): 2331-2349, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-32967524

RESUMO

Cellular RNAs are pervasively tagged with diverse chemical moieties, collectively called epitranscriptomic modifications. The methylation of adenosine at N6 position generates N6-methyladenosine (m6A), which is the most abundant and reversible epitranscriptomic modification in mammals. The m6A signaling is mediated by a dedicated set of proteins comprised of writers, erasers, and readers. Contrary to the activation-repression binary view of gene regulation, emerging evidence suggests that the m6A methylation controls multiple aspects of mRNA metabolism, such as splicing, export, stability, translation, and degradation, culminating in the fine-tuning of gene expression. Brain shows the highest abundance of m6A methylation in the body, which is developmentally altered. Within the brain, m6A methylation is biased toward neuronal transcripts and sensitive to neuronal activity. In a healthy brain, m6A maintains several developmental and physiological processes such as neurogenesis, axonal growth, synaptic plasticity, circadian rhythm, cognitive function, and stress response. The m6A imbalance contributes to the pathogenesis of acute and chronic CNS insults, brain cancer, and neuropsychiatric disorders. This review discussed the molecular mechanisms of m6A regulation and its implication in the developmental, physiological, and pathological processes of the brain.


Assuntos
Adenosina/análogos & derivados , Encéfalo/crescimento & desenvolvimento , Encéfalo/metabolismo , RNA/metabolismo , Adenosina/metabolismo , Encéfalo/fisiologia , Ritmo Circadiano/genética , Ritmo Circadiano/fisiologia , Cognição/fisiologia , Epigenômica/métodos , Regulação da Expressão Gênica , Humanos , Metilação , Doenças do Sistema Nervoso/metabolismo , Neurogênese/genética , Neurogênese/fisiologia , Plasticidade Neuronal/genética , Plasticidade Neuronal/fisiologia , RNA Mensageiro/metabolismo , Estresse Fisiológico/genética
18.
Artigo em Inglês | MEDLINE | ID: mdl-32222683

RESUMO

Most of the birds's adaptations for migration have a neuroendocrine origin, triggered by changes in photoperiod and the patterns of Earth's magnetic field. Migration phenomenology has been well described in the past decades, yet the genetic structure behind it remains terra incognita. We used RNA-Seq data to investigate which biological functions are linked with the seasonal brain adaptations of a long-distance trans-continental migratory passerine, the Northern Wheatear (Oenanthe oenanthe). We sequenced the wheatear's transcriptomes at three different stages: lean birds, a characteristic phenotype before the onset of migration, during fattening, and at their maximal migratory body mass. We identified a total of 15,357 genes in the brain of wheatears, of which 84 were differentially expressed. These were mostly related to nervous tissue development, angiogenesis, ATP production, innate immune response, and antioxidant protection, as well as GABA and dopamine signalling. The expression pattern of differentially expressed genes is correlated with typical phenotypic changes before migration, such as hyperphagia, migratory restlessness, and a potential increment in the visual and spatial memory capacities. Our work points out, for future studies, biological functions found to be involved in the development of the migratory phenotype -a unique model to study the core of neural, energetic and muscular adaptations for endurance exercise. Comparison of wheatears' transcriptomic data with two other studies with similar goals shows no correlation among the trends in the gene expression. It highlights the complexity and diversity of adaptations for long-distance migration in birds.


Assuntos
Adaptação Fisiológica , Migração Animal/fisiologia , Encéfalo/metabolismo , Estações do Ano , Aves Canoras/fisiologia , Transcriptoma , Animais , Aves Canoras/genética
19.
Artigo em Inglês | MEDLINE | ID: mdl-30984110

RESUMO

Intrauterine growth restriction (IUGR) is a complex global healthcare issue. Concerted research and clinical efforts have improved our knowledge of the neurodevelopmental sequelae of IUGR which has raised the profile of this complex problem. Nevertheless, there is still a lack of therapies to prevent the substantial rates of fetal demise or the constellation of permanent neurological deficits that arise from IUGR. The purpose of this article is to highlight the clinical and translational gaps in our knowledge that hamper our collective efforts to improve the neurological sequelae of IUGR. Also, we draw attention to cutting-edge tools and techniques that can provide novel insights into this disorder, and technologies that offer the potential for better drug design and delivery. We cover topics including: how we can improve our use of crib-side monitoring options, what we still need to know about inflammation in IUGR, the necessity for more human post-mortem studies, lessons from improved integrated histology-imaging analyses regarding the cell-specific nature of magnetic resonance imaging (MRI) signals, options to improve risk stratification with genomic analysis, and treatments mediated by nanoparticle delivery which are designed to modify specific cell functions.

20.
Brain Behav ; 8(9): e01090, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-30112813

RESUMO

INTRODUCTION: Functional magnetic resonance imaging (fMRI) combined with simultaneous electroencephalography (EEG-fMRI) has become a major tool in mapping epilepsy sources. In the absence of detectable epileptiform activity, the resting state fMRI may still detect changes in the blood oxygen level-dependent signal, suggesting intrinsic alterations in the underlying brain physiology. METHODS: In this study, we used coefficient of variation (CV) of critically sampled 10 Hz ultra-fast fMRI (magnetoencephalography, MREG) signal to compare physiological variance between healthy controls (n = 10) and patients (n = 10) with drug-resistant epilepsy (DRE). RESULTS: We showed highly significant voxel-level (p < 0.01, TFCE-corrected) increase in the physiological variance in DRE patients. At individual level, the elevations range over three standard deviations (σ) above the control mean (µ) CVMREG values solely in DRE patients, enabling patient-specific mapping of elevated physiological variance. The most apparent differences in group-level analysis are found on white matter, brainstem, and cerebellum. Respiratory (0.12-0.4 Hz) and very-low-frequency (VLF = 0.009-0.1 Hz) signal variances were most affected. CONCLUSIONS: The CVMREG increase was not explained by head motion or physiological cardiorespiratory activity, that is, it seems to be linked to intrinsic physiological pulsations. We suggest that intrinsic brain pulsations play a role in DRE and that critically sampled fMRI may provide a powerful tool for their identification.


Assuntos
Mapeamento Encefálico/métodos , Encéfalo/fisiopatologia , Epilepsia Resistente a Medicamentos/fisiopatologia , Eletroencefalografia/métodos , Imageamento por Ressonância Magnética/métodos , Adulto , Feminino , Humanos , Magnetoencefalografia/métodos , Masculino
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