Dietary polyphenols and neurogenesis: Molecular interactions and implication for brain ageing and cognition.

[eng] The increased number of elderly people worldwide poses a major medical and socio-economic challenge: the search of strategies to combat the consequences of the aging process. Oxidative stress and inflammation have been pointed out as the leading causes of brain aging, which in turn alters the functionality of brain. In this context, decline in adult neurogenesis (AN), due to modifications in the neural progenitor stem cells (NSCs) and their microenvironment, is among the aging alterations contributing to cognitive decline. Therefore, the consumption or administration of antioxidant and anti-inflammatory molecules, such as dietary polyphenols, is under study as a potential beneficial strategy for preventing brain aging alterations including AN decline. Polyphenols, through their antioxidant and anti-inflammatory properties, modulate several cascades and effectors involved in the regulation of AN (e.g., SIRT1, Wnt, NF-κB and Nrf2, among others). This work summarizes the latest discoveries regarding the mechanisms whereby polyphenols preserve AN and counteract the cognitive decline present in aging

Dietary polyphenols as promising molecules to prevent dementia

[eng] Due to the increased number of elderly people worldwide, nowadays one of the major medical and socio-economic challenges is to search strategies to combat the consequences of aging process, reducing the incidence of neurodegenerative diseases such as dementia. Dementia is a clinical syndrome of chronic and progressive symptoms characterized by multiple cognitive deficits associated with aging, which includes impairment in memory and in other cognitive functions to the extent that it interferes with daily function. In the last years oxidative stress and inflammation have been pointed out as the leading causes of brain aging and neurodegeneration. Therefore,an approach for preventing some brain age-related diseases, such as dementia, may be the consumption or administration of polyphenols,which are natural compounds present in edible plants. Due to their antioxidant and anti-inflammatory properties, polyphenolshave been suggested such as a beneficial strategy against the development of brain aging and neurodegeneration. This chapter summarizes the latest discoveries regarding how polyphenols exert positive effects combating the biochemical mechanisms that originate aging and dementia,such as oxidative stress, inflammation and the aggregation of abnormal folding proteins, among others

Impact of Gut Microbiota in Brain Ageing: Polyphenols as Beneficial Modulators

[eng] Brain ageing is a complex physiological process that includes several mechanisms. It is characterized by neuronal/glial dysfunction, alterations in brain vasculature and barriers, and the decline in brain repair systems. These disorders are triggered by an increase in oxidative stress and a proinflammatory state, without adequate antioxidant and anti-inflammatory systems, as it occurs in young life stages. This state is known as inflammaging. Gut microbiota and the gut–brain axis (GBA) have been associated with brain function, in a bidirectional communication that can cause loss or gain of the brain’s functionality. There are also intrinsic and extrinsic factors with the ability to modulate this connection. Among the extrinsic factors, the components of diet, principally natural components such as polyphenols, are the most reported. The beneficial effects of polyphenols in brain ageing have been described, mainly due to their antioxidants and anti-inflammatory properties, including the modulation of gut microbiota and the GBA. The aim of this review was, by following the canonical methodology for a state-of-the-art review, to compose the existing evidenced picture of the impact of the gut microbiota on ageing and their modulation by polyphenols as beneficial molecules against brain ageing

Effects of Resveratrol and Other Polyphenols on the Most Common Brain Age-Related Diseases

[eng] Background: With global increase in elderly population, modern societies must find strategies to reduce the consequences of aging process; thereby decreasing the incidence of age-related neurodegenerative diseases. Oxidative stress and recently inflammation, have been pointed out as the leading causes of brain aging. Thereby, the consumption or administration of antioxidant and anti-inflammatory molecules, such as polyphenols, is a beneficial strategy recommended for preventing brain aging and several brain age-related diseases. Methods and Results: Several studies suggest that long term consumption of dietary polyphenols offers protection against development of neurodegenerative diseases. These beneficial effects are in part due to their antioxidant and anti-inflammatory properties, together with their positive role in the modulation of processes involved in the physiopathology of several neurodegenerative diseases (e.g., epigenetic factors, amyloid deposition, cholinesterase inhibition, autophagy, and neurotrophic factors, among others). Altogether, these molecules open the door to the research of new neuroprotective strategies. This review summarizes the latest discoveries in how polyphenols can exert positive effects on brain health in aging, emphasizing those effects on the diseases that most commonly affect the brain during aging: Parkinson's Disease (PD), Alzheimer's disease (AD), dementia and depression. Moreover, within are addressed the epigenetic effects of polyphenols as possible mediators in their positive effects on brain health, and the future challenges of research in this topic Conclusion: In brief, this review presents a report of state-of the art knowledge regarding the positive influences of polyphenols on the most common brain age-related diseases as well as in healthy brain aging

Impact of Gut Microbiota in Brain Ageing: Polyphenols as Beneficial Modulators

[eng] Brain ageing is a complex physiological process that includes several mechanisms. It is characterized by neuronal/glial dysfunction, alterations in brain vasculature and barriers, and the decline in brain repair systems. These disorders are triggered by an increase in oxidative stress and a proinflammatory state, without adequate antioxidant and anti-inflammatory systems, as it occurs in young life stages. This state is known as inflammaging. Gut microbiota and the gut-brain axis (GBA) have been associated with brain function, in a bidirectional communication that can cause loss or gain of the brain's functionality. There are also intrinsic and extrinsic factors with the ability to modulate this connection. Among the extrinsic factors, the components of diet, principally natural components such as polyphenols, are the most reported. The beneficial effects of polyphenols in brain ageing have been described, mainly due to their antioxidants and anti-inflammatory properties, including the modulation of gut microbiota and the GBA. The aim of this review was, by following the canonical methodology for a state-of-the-art review, to compose the existing evidenced picture of the impact of the gut microbiota on ageing and their modulation by polyphenols as beneficial molecules against brain ageing

Chronic α-tocopherol increases central monoamines synthesis and improves cognitive and motor abilities in old rats

[eng] Limiting enzymes in the synthesis of brain monoamines seems to be susceptible to oxidative damage, one of the most important factors in aging. It has been suggested that the use of anti-oxidants can reduce the rate of free radical production related with aging and the associated damage. Therefore, this study aims to analyze the effects of the chronic treatments with the anti-oxidant a-tocopherol (vitamin E) on central monoamines (high-performance liquid chromatography [HPLC] analysis) mediating cognitive functions, as well as on the evaluation of memory and motor abilities in old rats measured by radial maze, Barnes maze, novel object recognition test, and rotarod test. Results show that a-tocopherol significantly increased in a dose- and/or timedependent manner the synthesis rate and the levels of monoaminergic neurotransmitters (serotonin, dopamine, and noradrenaline) in the hippocampus and striatum, brain regions involved in memory processing and motor coordination. These positive neurochemical effects, largely due to an increased activity of the limiting enzymes in monoamines synthesis, tryptophan hydroxylase and tyrosine hydroxylase, were accompanied by an improvement in cognitive and motor abilities in old rats. Altogether these findings suggest that a-tocopherol exhibits neuroprotective actions in old rats; thus, diets with a-tocopherol might represent a promising strategy to mitigate or delay the cognitive and motor decline associate with aging and related-diseases

Chronic Polyphenon-60 or Catechin Treatments Increase Brain Monoamines Syntheses and Hippocampal SIRT1 Levels Improving Cognition in Aged Rats

[eng] Polyphenolic compounds from green tea have great interest due to its large CONSUMPTION and therapeutic potential on the age-associated brain decline. The current work compares a similar dose regimen of a whole-green-tea extract and catechin in old rats over the course of 36 days. Results showed a significant improvement in visuo-spatial working memory and episodic memory of old rats after polyphenolic compounds administration assessed by behavioral tests. No effects were observed on the age-associated motor coordination decline. Statistically, results were correlated with significant improvements, mainly in hippocampal and striatal noradrenergic and serotonergic systems, but also with the striatal dopaminergic system. Both polyphenolic treatments also reverted the age-associated reduction of the neuroinflammation by modulating protein sirtuin 1 (SIRT1) expression in hippocampus, but no effects were observed in the usual reduction of the histone-binding protein RBAP46/48 protein linked to aging. These results are in line with previous ones obtained with other polyphenolic compounds, suggesting a general protective effect of all these compounds on the age-associated brain decline, pointing to a reduction of the oxidative stress and neuroinflammatory status reduction as the leading mechanisms. Results also reinforce the relevance of SIRT1-mediated mechanism on the neuroprotective effect and rule out the participation of RBAP46/48 protein

Chronic Polyphenon-60 or Catechin treatments increase brain monoamines syntheses and hippocampal SIRT1 levels improving cognition in aged rats

[eng] Polyphenolic compounds from green tea have great interest due to its large consumption and therapeutic potential on the age-associated brain decline. The current work compares a similar dose regimen of a whole-green-tea extract and catechin in old rats over the course of 36 days. Results showed a significant improvement in visuo-spatial working memory and episodic memory of old rats after polyphenolic compounds administration assessed by behavioral tests. No effects were observed on the age-associated motor coordination decline. Statistically, results were correlated with significant improvements, mainly in hippocampal and striatal noradrenergic and serotonergic systems, but also with the striatal dopaminergic system. Both polyphenolic treatments also reverted the age-associated reduction of the neuroinflammation by modulating protein sirtuin 1 (SIRT1) expression in hippocampus, but no effects were observed in the usual reduction of the histone-binding protein RBAP46/48 protein linked to aging. These results are in line with previous ones obtained with other polyphenolic compounds, suggesting a general protective effect of all these compounds on the age-associated brain decline, pointing to a reduction of the oxidative stress and neuroinflammatory status reduction as the leading mechanisms. Results also reinforce the relevance of SIRT1-mediated mechanism on the neuroprotective effect and rule out the participation of RBAP46/48 protein

Resveratrol improves episodic-like memory and motor coordination through modulating neuroinflammation in old rats

[eng] Strategies focus on the use of molecules found in food derived from plants as polyphenols, arouse interest for combating aging. The polyphenol resveratrol, due to its antioxidants and anti-inflammatory properties, is increasingly studied, being still unknown their effects on episodic-like memory and motor coordination. This research evaluated the in vivo effect of chronic resveratrol treatment (20 mg/kg/day, i.p, 28 days) in episodiclike memory and motor coordination in non-pathological old rats, comparing with young and old vehicle-treated rats, using the novel object recognition and the rotarod tests. In combination with the analyses of the effect of resveratrol on the immunoreactivity of the main molecular proteins involved in neuroinflammation (SIRT1, SIRT1-75 kDa fragment, NF-κB acetylation) in the hippocampus of these rats. Results suggest a beneficial effect of resveratrol on episodic-like memory and in motor coordination through modulating neuroinflammation, acting on SIRT1 and NF-κB signaling pathway in the hippocampus of old rats

The Gaiaultracool dwarf sample – V: the ultracool dwarf companion catalogue

© 2024 The Authors. Published by Oxford University Press on behalf of Royal Astronomical Society. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY), https://creativecommons.org/licenses/by/4.0/We present the Ultracool Dwarf Companion Catalogue of 278 multiple systems, 32 of which are newly discovered, each with at least one spectroscopically confirmed Ultracool Dwarf, within a 100 pc volume-limited sample. This catalogue is compiled using the Gaia Catalogue of Nearby Stars for stellar primaries and the Gaia Ultracool Dwarf Sample for low-mass companions and includes 241 doubles, 33 triples, and 4 higher-order systems established from positional, proper motion, and parallax constraints. The catalogue seeks to identify probable benchmark systems within 100 pc to obtain model-independent astrophysical parameters of Ultracool Dwarfs. Chance alignment probabilities are calculated to evaluate the physical nature of each system. Astrometric and photometric data from Gaia Data Release 3 and the Two Micron All Sky Survey are included for all objects. We identify potential unseen companions using a combination of the renormalized unit weight error, image parameter determination statistics, non-single star solutions, and photometric blending as provided by Gaia, identifying hierarchical Ultracool triple systems. Our catalogue includes 17 White Dwarf - Ultracool Dwarf systems, whose ages are determined using cooling models. We also use the Gaia FLAME results and the BANYAN ς procedures to age 40 and 34 systems, respectively, and derive mass estimates from evolutionary models.Peer reviewe