A fiber-deprived diet causes cognitive impairment and hippocampal microglia-mediated synaptic loss through the gut microbiota and metabolites

Microbiome signatures of virulence in the oral-gut-brain axis influence Parkinson's disease and cognitive decline pathophysiology

The human microbiome is increasingly recognized for its crucial role in the development and progression of neurodegenerative diseases. While the gut-brain axis has been extensively studied, the contribution of the oral microbiome and gut-oral tropism in neurodegeneration has been largely overlooked. Cognitive impairment (CI) is common in neurodegenerative diseases and develops on a spectrum. In Parkinson's Disease (PD) patients, CI is one of the most common non-motor symptoms but its mechanistic development across the spectrum remains unclear, complicating early diagnosis of at-risk individuals. Here, we generated 228 shotgun metagenomics samples of the gut and oral microbiomes across PD patients with mild cognitive impairment (PD-MCI) or dementia (PDD), and a healthy cohort, to study the role of gut and oral microbiomes on CI in PD. In addition to revealing compositional and functional signatures, the role of pathobionts, and dysregulated metabolic pathways of the oral and gut microbiome in PD-MCI and PDD, we also revealed the importance of oral-gut translocation in increasing abundance of virulence factors in PD and CI. The oral-gut virulence was further integrated with saliva metaproteomics and demonstrated their potential role in dysfunction of host immunity and brain endothelial cells. Our findings highlight the significance of the oral-gut-brain axis and underscore its potential for discovering novel biomarkers for PD and CI.

An insight into the full aspects of bound polyphenols in dietary fiber: Interaction, composition, function and foundation as well as alteration in food processing

Dietary fiber (DF) and polyphenols are both bioactive compounds with various health-promoting effects while close relationship between them aroused wide concern in recent years. Abundant polyphenols combine with DF and contribute greatly to its beneficial effects. Although efforts made to uncover such bound polyphenols (BPs) from different angles before, systematic overview of full aspects is deficient. Here, more details about polyphenols conjugated in DF reported recently were summarized systematically. Meanwhile, the disposition of BPs in gastrointestinal tract and their interaction with microbiome were introduced to clarify the foundation of their functions. Moreover, considering the great impacts of food processing on polyphenols, different technics used in food handling were introduced with their effects on BPs emphatically discussed to provide guideline for reasonable application of specific technics for given materials. Our work is supposed to promote the understanding of BPs in DF and facilitate their future exploitation and application as a whole.

Therapeutic potential of gut microbiota modulation in epilepsy: A focus on short-chain fatty acids

According to the criteria established by the International League Against Epilepsy (ILAE), epilepsy is defined as a disorder characterized by at least two unprovoked seizures occurring more than 24 h apart. Its pathogenesis is closely related to various physiological and pathological factors. Advances in high-throughput metagenomic sequencing have increasingly highlighted the role of gut microbiota dysbiosis in epilepsy. Short-chain fatty acids (SCFAs), the major metabolites of the gut microbiota and key regulators of the gut-brain axis, support physiological homeostasis through multiple mechanisms. Recent studies have indicated that SCFAs not only regulate seizures by maintaining intestinal barrier integrity and modulating intestinal immune responses, but also affect the structure and function of the blood-brain barrier (BBB) and regulate neuroinflammation. This review, based on current literatures, explores the relationship between SCFAs and epilepsy, emphasizing how SCFAs affect epilepsy by modulating the intestinal barrier and BBB. In-depth studies on SCFAs may reveal their therapeutic potential and inform the development of gut microbiota-targeted epilepsy treatments.

Microbiota-induced inflammation mediates the impacts of a Western diet on hippocampal-dependent memory

Obesity is associated with impaired hippocampal-dependent memory, but the mechanisms driving this pathology are not fully understood. Western diets (WD) contribute to obesity, and previous reviews have described a role for WD in impaired hippocampal-dependent memory. However, there is need for a more detailed description of the pathways by which WD may impair memory. The short vs long-term effect of specific dietary components on brain structure and functions as well as the precise mechanism and molecular pathways involved are still not fully understood. This review focuses on the mechanisms and effects of gut microbiota-driven neuroinflammation. WD leads to changes and imbalance in bacterial taxa abundances that are deleterious to the host health (gut dysbiosis) and studies in rodent models show these changes are sufficient to impair hippocampal-dependent memory. Here, we discuss a variety of proposed mechanisms linking microbiota composition to hippocampal function, with a focus on neuroinflammation. Gut microbiota impacts gastrointestinal barrier function, leading to increased circulating proinflammatory bacterial products, increased blood-brain barrier permeability, and neuroinflammation.

Sea Cucumber Hydrolysates Alleviate Cognitive Deficits in D-Galactose-Induced C57BL/6J Aging Mice Associated with Modulation of Gut Microbiota

As the global elderly population is rising, concerns about cognitive decline and memory loss are becoming urgent. This study evaluated the potential of sea cucumber hydrolysates (SCH) from Stichopus japonicus in alleviating cognitive deficits using a D-galactose-induced murine aging model. The effects of SCH on behavior, hippocampal morphology, gut microbiota, hippocampal cholinergic system, brain-derived neurotrophic factor (BDNF) signaling, and neuroinflammatory pathways were investigated. Results showed that SCH ameliorated learning and memory deficits and reduced neuronal damage in aging mice. SCH also modulated gut microbiota, along with increased fecal short-chain fatty acids levels. Functional prediction revealed that alterations in gut microbiota were related to signal transduction. Further, SCH enhanced hippocampal cholinergic function through elevating acetylcholine (ACh) levels and inhibiting acetylcholinesterase (AChE) activity and activated BDNF signaling, consistent with predictions of gut microbiota function. Restoration of cholinergic homeostasis and transmission of the BDNF pathway might contribute to the inhibition of hippocampal neuroinflammation via suppressing microglial activation and the nuclear factor kappa-B (NF-κB) pathway. In summary, SCH attenuated cognitive deficits through suppressing neuroinflammation, which might be correlated with the signal transduction caused by regulating gut microbiota. Further validation will be conducted through microbiota depletion and fecal microbiota transplantation. These findings suggest that SCH is a promising functional component for counteracting aging-related cognitive deficits.

The Role of Nutraceuticals and Functional Foods in Mitigating Cellular Senescence and Its Related Aspects: A Key Strategy for Delaying or Preventing Aging and Neurodegenerative Disorders

As life expectancy continues to increase, it becomes increasingly important to extend healthspan by targeting mechanisms associated with aging. Cellular senescence is recognized as a significant contributor to aging and neurodegenerative disorders. This review examines the emerging role of nutraceuticals and functional foods as potential modulators of cellular senescence, which may, in turn, influence the development of neurodegenerative diseases. An analysis of experimental studies indicates that bioactive compounds, including polyphenols, vitamins, and spices, possess substantial antioxidants, anti-inflammatory and epigenetic properties. These nutritional senotherapeutic agents effectively scavenge reactive oxygen species, modulate gene expression, and decrease the secretion of senescence-associated secretory phenotype factors, minimizing cellular damage. Nutraceuticals can enhance mitochondrial function, reduce oxidative stress, and regulate inflammation, key factors in aging and diseases like Alzheimer's and Parkinson's. Furthermore, studies reveal that specific bioactive compounds can reduce senescence markers in cellular models, while others exhibit senostatic and senolytic properties, both directly and indirectly. Diets enriched with these nutraceuticals, such as the Mediterranean diet, have been correlated with improved brain health and the deceleration of aging. Despite these promising outcomes, direct evidence linking these compounds to reducing senescent cell numbers remains limited, highlighting the necessity for further inquiry. This review presents compelling arguments for the potential of nutraceuticals and functional foods to promote longevity and counteract neurodegeneration by exploring their molecular mechanisms. The emerging relationship between dietary bioactive compounds and cellular senescence sets the stage for future research to develop effective preventive and therapeutic strategies for age-related diseases.

Neuroprotective effect of folic acid by maintaining DNA stability and mitochondrial homeostasis through the ATM/CHK2/P53/PGC-1α pathway in alcohol-exposed mice

Excessive drinking leads to alcoholic brain injury, which is characterized by neuroinflammation, cognitive decline and motor dysfunction. These pathological features are closely related to chromosomal DNA damage and mitochondrial dysfunction. In this study, we aimed to uncover the neuroprotective effects of folic acid (FA) in mice with alcoholic brain injury. C57BL/6J mice were used to establish the murine model of alcoholic brain injury after 12 weeks of alcohol exposure. FA treatment significantly increased the levels of ATP and mitochondrial DNA (mtDNA) copy number in brain tissues of alcohol-exposed mice, and regulated the imbalance of mitochondrial homeostasis in cortical nerve cells. Furthermore, it could reduce the leakage of mtDNA into the cytoplasm, thereby inhibiting the cGAS/STING/NLRP3 inflammatory pathway and alleviating neuroinflammation. In addition, FA treatment reduced DNA damage in peripheral blood lymphocytes and decreased the expression of 53BP1 and γ-H2AX proteins in brain tissues of alcohol-exposed mice. At the molecular level, FA reduced DNA damage by downregulating the ATM/CHK2/P53 pathway and induced the expression of peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α), which further inversely enhanced mitochondrial function through positive feedback. Collectively, this study provides experimental evidence that FA protects DNA stability and mitochondrial homeostasis in alcohol-exposed mice by downregulating the ATM/CHK2/P53/PGC-1α signaling pathway.

Ruminal microbial responses to Moringa oleifera feed in lactating goats (Capra hircus): A metagenomic exploration

The purpose of the current study was to explore the effects of Moringa oleifera feed on the taxonomy and function of the rumen microbial community, and further to evaluate its impact on milk yield and body weight in lactating goats. Nineteen goats were divided into moringa leaf diet (ML; n = 10) and masoor straw (MS; n = 9) groups. For each group fortnight milk yield and body weight was recorded. Rumen solid and liquid fraction samples were processed for metagenomic shotgun sequencing and further analysed. The pairwise comparison between the two groups showed a significant increase (p-value- <0.01) in milk yield of the ML goats after the 4th fortnight interval onwards. The metagenomic analysis revealed Bacteroidetes and Firmicutes are the most abundant phyla, with increased Bacteroidetes in response to the moringa diet. The ML group exhibited a reduction in microbial diversity, with an increase in Prevetolla and Bacteroidales populations which are positively associated with carbohydrate, protein, and VFA metabolism, and an increased proportions of Treponema sp., Ruminococcus sp., Ruminobacter amylophilus, and Aeromonas, indicating improved cellulose and nitrogen metabolism. KEGG analysis revealed significant changes in microbial gene pool and metabolic pathways, particularly in carbohydrate metabolism, propanoate metabolism, and fatty acid synthesis genes. These microbial and functional shifts are correlated with improvements in milk yield, growth rates, and potentially reduced methane emissions.This study highlighted the potential benefits of feeding moringa in the animal production system. However, furthermore experimental evidence including genetic and environmental effects is needed for a comprehensive understanding of moringa feed's impact on goat health and productivity.

Neuroprotective Effects of Qi Jing Wan and Its Active Ingredient Diosgenin Against Cognitive Impairment in Plateau Hypoxia

Background/Objectives: High-altitude environments have a significant detrimental impact on the cognitive functions of the brain. Qi Jing Wan (QJW), a traditional herbal formula composed of Angelica sinensis, Astragalus membranaceus, and Rhizoma Polygonati Odorati, has demonstrated potential efficacy in treating cognitive disorders. However, its effects on cognitive dysfunction in plateau hypoxic environments remain unclear. Methods: In this study, acute and chronic plateau cognitive impairment mouse models were constructed to investigate the preventive and therapeutic effects of QJW and its significant active ingredient, diosgenin (Dio). Behavioral experiments were conducted to assess learning and memory in mice. Morphological changes in hippocampal neurons and synapses were assessed, and microglial activation and inflammatory factor levels were measured to evaluate brain damage. Potential active ingredients capable of crossing the blood-brain barrier were identified through chemical composition analysis and network database screening, followed by validation in animal and brain organoid experiments. Transcriptomics analysis, immunofluorescence staining, and molecular docking techniques were employed to explore the underlying mechanisms. Results: QJW significantly enhanced learning and memory abilities in plateau model mice, reduced structural damage to hippocampal neurons, restored NeuN expression, inhibited inflammatory factor levels and microglial activation, and improved hippocampal synaptic damage. Transcriptomics analysis revealed that Dio alleviated hypoxic brain damage and protected cognitive function by regulating the expression of PDE4C. Conclusions: These findings indicate that QJW and its significant active ingredient Dio effectively mitigate hypoxic brain injury and prevent cognitive impairment in high-altitude environments.

Intestinal 8 gingerol attenuates TBI-induced neuroinflammation by inhibiting microglia NLRP3 inflammasome activation in a PINK1/Parkin-dependent manner

BACKGROUND

traumatic brain injury (TBI) is irreversible brain damage, leading to inflammation and cognitive dysfunction. Microglia involved in the inflammatory response after TBI. The gut microbiota, known as the body's "second brain," regulates neurogenesis and immune responses, but its precise role in regulating TBI remains unclear.

PURPOSE

to investigate the effect of gut microbiota and metabolites disorder on TBI injury.

STUDY DESIGN

16SrRNA and metabolomics compared gut microbiota and metabolites in sham group and TBI group, then proved that the differential metabolite 8-gingerol (8G) alleviated the microglia neuroinflammatory response after TBI.

METHODS

fecal microbiota transplantation explored the role of dysbiosis in TBI. LC/MS detected the content of 8-gingerol in cecum, blood, and brain. HE, Nissl, Tunel staining and mNSS score evaluated brain injury. Western blot and immunofluorescence detected the expression of inflammasome-related proteins and mitophagy-related proteins in brain tissue and BV2 cells. RNA sequencing analyzed the molecular mechanism of 8-gingerol.

RESULT

rats transplanted with TBI feces had worse brain injury and neurological deficits than those with normal feces. 16SrRNA and metabolomics found that TBI caused dysbiosis and decreased 8-gingerol level, leading to severe neuroinflammation. Mechanistically, 8-gingerol inhibited NLRP3 inflammasome by promoting PINK1-Parkin mediated mitophagy in microglia. Inhibition of Parkin, through either small interfering RNA or the inhibitor 3MA reversed the inhibitory effect of 8-gingerol on NLRP3 by blocking mitophagy. BV2 cells transcriptome showed that 8-gingerol significantly increased the expression of autophagy factor Wipi1, and small interfering RNA of Wipi1 abolished the effect of 8-gingerol on promoting mitophagy and the inhibitory effect on NLRP3.

CONCLUSION

our findings shed light on the pivotal role of gut microbes in TBI, and identify 8 gingerol as an important anti-inflammatory compound during TBI.

Adolescent social isolation decreases colonic goblet cells and impairs spatial cognition through the reduction of cystine

Negative experiences during adolescence, such as social isolation (SI), bullying, and abuse, increase the risk of psychiatric diseases in adulthood. However, the pathogenesis of psychiatric diseases induced by these factors remain poorly understood. In adolescents, stress affects the intestinal homeostasis in the gut-brain axis. This study determined whether adolescent SI induces behavioral abnormalities by disrupting colonic function. Adolescent mice exposed to SI exhibit spatial cognitive deficits and microglial activation in the hippocampus (HIP). SI decreased the differentiation of mucin-producing goblet cells, which was accompanied by alterations in the composition of the gut microbiota, particularly the depletion of mucin-feeding bacteria. Treatment with rebamipide, which promotes goblet cell differentiation in the colon, attenuated SI-induced spatial cognitive deficits and microglial activation in the HIP and decreased cystine, a downstream metabolite of homocysteine. Treatment with cystine ameliorated SI-induced spatial cognitive deficits and increased microglial C-C motif chemokine ligand 7 (CCL7) levels in the HIP. Inhibition of CCL7 receptors by antagonists of CC motif chemokine receptors 2 (CCR2) and 3 (CCR3) in the HIP prevented spatial cognitive deficits induced by SI. Infusion of CCL7 into the HIP following microglial ablation with clodronate liposome induced spatial cognitive deficits. These findings suggest that adolescent SI decreases serum cystine levels by damaging the colonic goblet cells, resulting in spatial cognitive deficits by triggering microglial activation in the HIP. Our results indicate that increased CCL7 expression in hippocampal microglia may contribute to spatial cognitive deficits by activating CCR2 and CCR3.

Nootropic foods in neurodegenerative diseases: mechanisms, challenges, and future

Neurodegenerative diseases (NDDs) such as Alzheimer's and Parkinson's disease are increasing globally and represent a significant cause of age-related death in the population. Recent studies emphasize the strong association between environmental stressors, particularly dietary factors, and brain health and neurodegeneration unsatisfactory outcomes. Despite ongoing efforts, the efficiency of current treatments for NDDs remains wanting. Considering this, nootropic foods with neuroprotective effects are of high interest as part of a possible long-term therapeutic strategy to improve brain health and alleviate NDDs. However, since it is a new and emerging area in food and neuroscience, there is limited information on mechanisms and challenges to consider for this to be a successful intervention. Here, we seek to address these gaps by presenting a comprehensive review of possible pathways or mechanisms including mutual interactions governing nootropic food metabolism, linkages of the pathways with NDDs, intake, and neuroprotective properties of nootropic foods. We also discuss in-depth intervention with nootropic compounds and dietary patterns in NDDs, providing a detailed exploration of their mechanisms of action. Additionally, we analyze the demand, challenges, and future directions for successful development of nootropic foods targeting NDDs.

Bridging the gap between gut microbiota and sleep disorders through intermediary metabolites

BACKGROUND

Research has suggested an interaction between gut microbiota and sleep, yet the causal relationships between gut microbiota, metabolites, and sleep disorders remain unclear. This study aims to uncover these relationships.

METHODS

We obtained genome-wide data for 196 gut microbiota (GM) species (N = 18,340), 1,400 metabolites (N = 8,299), and sleep disorders (N = 361,194). Mendelian randomization(MR) analyses were conducted using the Inverse Variance Weighted (IVW) method, MR-Egger, Weighted Median method, Weighted Mode method, and Simple Mode method to infer causality. The IVW method was used for primary analysis results. Significant microbiota and causal metabolites were further analyzed to clarify the associations between the three. All results were tested for heterogeneity, pleiotropy, and sensitivity to assess the stability of the findings.

RESULTS

The Mendelian randomization results revealed causal relationships between four gut microbiota species and sleep disorders: Genus.Dorea, Genus.Parasutterell, Genus.Slackia, and Order.Bacillales. Additionally, we identified 39 causal metabolites Related to sleep disorders, with 7 of these being associated with 3 causal microbiota species at the genus level. All results showed no heterogeneity or horizontal pleiotropy.

CONCLUSION

Through two-sample Mendelian randomization studies, we identified three gut microbiota species at the genus level genetically linked to sleep disorders through seven plasma metabolites, revealing causal relationships between these three factors. These biomarkers provide new insights into the mechanisms of sleep disorders and may contribute to their prevention, diagnosis, and treatment.

Improved effect of antibiotic treatments on the hippocampal spatial memory dysfunction of mice induced by high fluoride exposure: Insight from assembly processes and co-occurrence networks of gut microbial community

High fluoride exposure was widely demonstrated to be related with brain memory impairment. Since the absorption of F- enters the body mainly through the gastrointestinal tract, studying the effects of excessive intake of fluoride on brain memory function in various gut microbiome states might have profound implications for the prevention of fluorosis because growing evidence revealed the significance of the "microbiota-gut-brain" axis (MGBA). In the present study, we aimed to illustrate the potential mechanism of gut microbiota on high fluoride exposure-induced hippocampal lesions and spatial memory dysfunction in mice by the various intestinal microecological environments, which were constructed by antibiotic treatment. Mice fed with normal (CG1 and Exp1 groups) or sodium-fluoride (CG2 and Exp2 groups; 24 mg/kg sodium fluoride per mouse) by gavage administration with or without antibiotic treatments, a combination of metronidazole (1 g/L) and ciprofloxacin (0.2 g/L) in drinking water. Mice gavaged with excessive sodium fluoride alone exhibited reduced weight gain, hippocampal tissue damages, spatial memory levels dysfunction, impaired intestinal permeability, decreased inflammatory cytokines expression and antioxidant capability in the hippocampal and ileal tissues. In contrast, antibiotic intervention significantly reversed these high fluoride exposure-induced hippocampal and ileal changes.16S rRNA high throughput sequencing found that ileal microbiota were dominated by abundant taxa, which is conducive to constructing microbial interaction networks and module communities, and identifying keystone species targeted by high fluoride exposure compared with colonic microbiome. In addition, the microbial community composition and assembly mechanism of ileal microbiome under the effects of antibiotics were suitable for revealing the characteristics of high fluoride environment. In the later analysis, Lactobacillus, Staphylococcus, Muribaculaceae and Robinsoniella were considered as the keystone species targeted by high fluoride-exposed mice based on the analysis of network node properties and niche overlap of ileal microbes. Spearman rank correlation demonstrated that these keystone species had significant effects on hippocampal memory levels and intestinal health, as well as microbial communities functions. Compared to previous researches, this study further revealed intestinal microbial coummunity mediated the underlying mechanism through antibiotic treatment against high fluoride-induce hippocampal spatial memory impairment.

Dynamic changes in the gut microbiota play a critical role in age-associated cognitive dysfunction via SCFAs and LPS synthesis metabolic pathways during brain aging

BACKGROUND

Gut microbiota plays an essential role in cognitive dysfunction during aging. The aim of this study was to investigate the dynamic alterations in the gut microbiota and screen for key gut bacterial taxa correlated with age-associated cognitive dysfunction during natural aging.

METHODS

16S rRNA gene sequencing was performed to determine the composition of the gut microbiota in faecal samples from SAMR1 and SAMP8 mice, cognitively normal controls (NC), and patients with amnestic mild cognitive impairment (aMCI). Faecal microbiota transplantation (FMT) and GMrepo database were used to screen key gut microbiota associated with cognitive decline in aging mice and humans.

RESULTS

The composition of the gut microbiota dynamically changed during natural aging in SAMR1 and SAMP8 mice, as well as in healthy subjects of different ages extracted from the GMrepo database. FMT from SAMR1 to SAMP8 mice altered the gut microbiota composition and improved the cognitive impairment in SAMP8 mice. Key gut bacterial taxa, including Lactobacillus, Akkermansia, Clostridium, Oscillospira and Dorea, were screened and validated to correlate with aging-associated cognitive decline. The function of the key gut bacterial taxa predicted by PICRUSt2 indicated that the metabolic pathways related to short-chain fatty acids (SCFAs) and lipopolysaccharide (LPS) synthesis were involved in age-associated cognitive dysfunction during natural aging.

CONCLUSION

These results demonstrate that the composition of the gut microbiota changes dynamically during brain aging, with some key gut bacterial taxa playing critical roles in age-associated cognitive dysfunction through SCFAs and LPS synthesis metabolic pathways.

Effects of fermented bamboo fiber on intestinal health and fecal pollutants in weaned piglets

Introduction

Weaning stress adversely affects piglet growth and development, thereby reducing the economic efficiency of pig farming operations. Furthermore, pig feces are a major source of environmental pollution, underscoring the need for effective strategies to mitigate fecal output at its source.

Methods

This study investigated the effects of dietary supplementation with fermented bamboo fiber (FBF) on growth performance, intestinal barrier integrity, gut microbiota composition, and fecal pollutant levels in weaned piglets. A total of 144 Duroc × Landrace × Yorkshire piglets, weaned at 21 days of age, were randomly assigned to 4 groups, with six replicates per group and 6 piglets per replicate. The control group (CON) received a basal diet, while the three treatment groups were fed the basal diet supplemented with 1, 1.5, and 2% FBF, respectively. The trial lasted 30 days.

Results

The findings revealed that FBF supplementation fortified the intestinal barrier, modulated colonic microbial communities, and decreased fecal pollutant levels. Among the treatment groups, supplementation with 1.5% FBF produced the most significant improvements in piglets' growth performance and intestinal barrier function, as well as the strongest microbial interactions and the greatest reduction in fecal pollutants.

Discussion

These results suggest that FBF supplementation can alleviate weaning stress and mitigate the environmental impact of pig feces, with 1.5% identified as the optimal supplementation level.

Lifestyle Interventions and Innovative Approaches for the Management of Neurodegenerative Disorders in Older Adults-State-Of-The-Art and Future Directions

Aging increases the risk of neurodegenerative diseases (NDs) like Alzheimer's (AD) and Parkinson's (PD), characterized by neuronal loss and cognitive decline. Potential preventive/therapeutic interventions also include lifestyle changes like nutrition & diet, exercise, leisure and social engagement. Here, we discuss several lifestyle interventions for healthy brain aging, and in older adults with NDs. Balanced diets like the Mediterranean and MIND diets can reduce cognitive decline during aging. Long-term use of specific nutrient combinations in medical food may also exert benefits on memory. Metabolic interventions like calorie restriction (CR) and intermittent fasting (IF) have shown potential benefits in aging. However, their effects on cognitive function in older adults were modestly explored and remain unclear. Clinical trials are ongoing to test the cognitive and health outcomes of CR/IF variants in older adults with AD or PD (associated or not with metabolic disorders). We also highlight the role of cognitive reserve (CoR) in delaying dementia symptoms. Engaging in diverse leisure activities like music and bilingualism may enhance CoR and reduce AD risk. Finally, we outline future directions for promoting healthy brain aging through lifestyle interventions (e.g., personalized diets, precision nutrition, synergistic lifestyle approaches, AI-based technologies to monitor the effectiveness of lifestyle practices).

The gut microbiota-immune-brain axis: Therapeutic implications

The microbiota-gut-brain axis has major implications for human health including gastrointestinal physiology, brain function, and behavior. The immune system represents a key pathway of communication along this axis with the microbiome implicated in neuroinflammation in health and disease. In this review, we discuss the mechanisms as to how the gut microbiota interacts with the brain, focusing on innate and adaptive immunity that are often disrupted in gut-brain axis disorders. We also consider the implications of these observations and how they can be advanced by interdisciplinary research. Leveraging an increased understanding of how these interactions regulate immunity has the potential to usher in a new era of precision neuropsychiatric clinical interventions for psychiatric, neurodevelopmental, and neurological disorders.

Association of the dietary index for gut microbiota with sleep disorder among US adults: the mediation effect of dietary inflammation index

Background

Previous studies have confirmed the relationship between gut microbiota and sleep disorders, characterized by the persistent inability to achieve adequate sleep, with dietary composition playing a key role in maintaining microbiota homeostasis. Our study aims to explore the relationship between the newly proposed Dietary Index for Gut Microbiota (DI-GM) and sleep disorders, as well as whether the Dietary Inflammatory Index (DII) mediates this relationship.

Methods

This study is based on data from 30,406 participants in the National Health and Nutrition Examination Survey (NHANES) from 2005 to 2018, a cross-sectional survey that represents the U.S. adult population. We used multivariable logistic regression models to examine the relationship between DI-GM and sleep disorders. Subgroup interaction analyses were conducted to assess the stability of the results. Mediation analysis was employed to explore the effect of the Dietary Inflammatory Index (DII) on the relationship between DI-GM and sleep disorders.

Results

The DI-GM score was significantly negatively correlated with sleep disorders. After adjusting for covariates, each unit increase in DI-GM was associated with a 5% reduction in the prevalence of sleep disorders (p < 0.001). Additionally, there was a trend toward a decrease in the prevalence of sleep disorders with increasing DI-GM (trend p < 0.05). Dose-response curve analysis revealed a linear relationship between DI-GM and sleep disorders, with higher DI-GM scores being associated with lower prevalence of sleep disorders. DII was positively correlated with sleep disorders (p < 0.001) and decreased as DI-GM increased (β = -0.37, p < 0.001). Mediation analysis showed that DII significantly mediated the relationship between DI-GM and sleep disorders, with a mediation proportion of 27.36% (p < 0.001).

Conclusion

The results of this study indicate that the DI-GM score was significantly negatively correlated with sleep disorders. A higher DI-GM score is associated with a lower incidence of sleep disorders, while the DII significantly mediated the relationship between DI-GM and sleep disorders. Specifically, an increase in DII may attenuate the protective effect of DI-GM on sleep disorders.

A glucan from Ganoderma lucidum: Structural characterization and the anti-inflammatory effect on Parkinson's disease via regulating dysfunctions of intestinal microecology and inhibiting TLR4/MyD88/NF-κB signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Ganoderma lucidum (Curtis) P. Karst (G. lucidum) is a traditional Chinese medicinal fungus, used to exert a beneficial effect on central nervous system, such as Parkinson's disease (PD). Polysaccharide is its main active ingredient, but the structural characterization and the mechanisms of the beneficial effect on PD remain to be elucidated.

AIM OF THE STUDY

To obtain a purified G. lucidum polysaccharide and elucidate its structure, investigate the anti-inflammatory effect on PD and explore its potential mechanisms.

MATERIALS AND METHODS

The structure of polysaccharide was analyzed through methylation analysis and NMR analysis. The anti-inflammatory effect on PD were explored in a MPTP-induced mouse model. A comprehensive microbiota-gut-metabolomics analysis was executed and subsequently deliberated, focusing on the regulation of dysfunctions of intestinal microecology. The potential mechanisms were investigated using a LPS-induced Caco-2 cell model.

RESULTS

A purified glucan, GLPZ-2 was obtained. GLPZ-2 was with triple helical structure and its backbone was found to be primarily composed of 1,6-α-D-Glcp, 1,4-α-D-Glcp, 1,4,6-α-D-Glcp and 1,3,6-β-D-Glcp, with branches at the C-3 and C-4 position by t-α-D-Glcp. PD mice experiments showed that GLPZ-2 could improve motor symptoms, reduce pathological damage and decrease brain protein expression of α-Syn, IL-6, IL-1β and TNF-α. GLPZ-2 also could regulate the gut microbiota and fecal metabolites to restore to normal trend, increase SCFAs content and inhibit TLR4/MyD88/NF-κB pathway in intestine.

CONCLUSIONS

GLPZ-2 exhibits an anti-inflammatory effect on PD, which provide a foundational basis for the application of GLPZ-2 as an effective drug to prevent and delay PD.

Gut microbiota in multiple sclerosis and animal models

Multiple sclerosis (MS) is a chronic central nervous system (CNS) neurodegenerative and neuroinflammatory disease marked by a host immune reaction that targets and destroys the neuronal myelin sheath. MS and correlating animal disease models show comorbidities, including intestinal barrier disruption and alterations of the commensal microbiome. It is accepted that diet plays a crucial role in shaping the microbiota composition and overall gastrointestinal (GI) tract health, suggesting an interplay between nutrition and neuroinflammation via the gut-brain axis. Unfortunately, poor host health and diet lead to microbiota modifications that could lead to significant responses in the host, including inflammation and neurobehavioral changes. Beneficial microbial metabolites are essential for host homeostasis and inflammation control. This review will highlight the importance of the gut microbiota in the context of host inflammatory responses in MS and MS animal models. Additionally, microbial community restoration and how it affects MS and GI barrier integrity will be discussed.

Structural characteristics of a heteropolysaccharide from Ganoderma lucidum and its protective effect against Alzheimer's disease via modulating the microbiota-gut-metabolomics

Ganoderma lucidum is a traditional Chinese medicine used to treat Alzheimer's disease (AD), whose main active ingredient is polysaccharides. A heteropolysaccharide named GLPZ-1 was isolated from Ganoderma lucidum. GLPZ-1 (6.608 kDa) predominantly consisted of Glc and minor Gal. The results of GC-MS and NMR analyses indicated that the backbone of GLPZ-1 was mainly composed of 1,4-α-D-Glcp, 1,4,6-α-Glcp and a minor amount of 1,3,4-β-D-Glcp, which was substituted with complex side chains at C-6 of 1,4,6-α-D-Glcp and at C-3 of 1,3,4-β-D-Glcp. GLPZ-1 demonstrated a protective effect on AD rats by improving behavioral abnormalities, alleviating pathological damage and ameliorating levels of IL-6, IL-1β, TNF-α and Th17, which were associated with GLPZ-1 modulating the microbiota-gut-metabolomics of AD rats. GLPZ-1 regulated the gut microbiota in AD rats by increasing the abundance of Bacteroides, unclassified_Lachnospiraceae, Lactobacillus, Pediococcus, Oscillibacter, Lachnoclostridium and Bifidobacterium, while simultaneously reducing the abundance of Pseudomonas and Desulfovibrio. GLPZ-1 could regulate fecal metabolites in AD rats tending towards the normal levels. These regulated fecal metabolites belonged to fatty acid metabolism, cholesterol and bile acid metabolism, neurotransmitters and aromatic amino acid metabolism. These findings provide a preliminary research basis for the exploitation of GLPZ-1 as an effective drug to prevent and delay AD.

Neuro-Nutrition and Exercise Synergy: Exploring the Bioengineering of Cognitive Enhancement and Mental Health Optimization

The interplay between nutrition, physical activity, and mental health has emerged as a frontier in bioengineering research, offering innovative pathways for enhancing cognitive function and psychological resilience. This review explores the neurobiological mechanisms underlying the synergistic effects of tailored nutritional strategies and exercise interventions on brain health and mental well-being. Key topics include the role of micronutrients and macronutrients in modulating neurogenesis and synaptic plasticity, the impact of exercise-induced myokines and neurotrophins on cognitive enhancement, and the integration of wearable bioelectronics for personalized monitoring and optimization. By bridging the disciplines of nutrition, psychology, and sports science with cutting-edge bioengineering, this review highlights translational opportunities for developing targeted interventions that advance mental health outcomes. These insights are particularly relevant for addressing global challenges such as stress, anxiety, and neurodegenerative diseases. The article concludes with a roadmap for future research, emphasizing the potential of bioengineered solutions to revolutionize preventive and therapeutic strategies in mental health care.

Harnessing Gut Microbiota for Biomimetic Innovations in Health and Biotechnology

The gut microbiota is a complex and dynamic ecosystem that plays a fundamental role in human health by regulating immunity, metabolism, and the gut-brain axis. Beyond its critical physiological functions, it has emerged as a rich source of inspiration for biomimetic innovations in healthcare and biotechnology. This review explores the transformative potential of microbiota-based biomimetics, focusing on key biological mechanisms such as resilience, self-regulation, and quorum sensing. These mechanisms have inspired the development of innovative applications, including personalized probiotics, synbiotics, artificial microbiomes, bioinspired biosensors, and bioremediation systems. Such technologies aim to emulate and optimize the intricate functions of microbial ecosystems, addressing challenges in healthcare and environmental sustainability. The integration of advanced technologies, such as artificial intelligence, bioengineering, and multi-omics approaches, has further accelerated the potential of microbiota biomimetics. These tools enable the development of precision therapies tailored to individual microbiota profiles, enhance the efficacy of diagnostic systems, and facilitate the design of environmentally sustainable solutions, such as waste-to-energy systems and bioremediation platforms. Emerging areas of innovation, including gut-on-chip models and synthetic biology, offer unprecedented opportunities for studying and applying microbiota principles in controlled environments. Despite these advancements, challenges remain. The replication of microbial complexity in artificial environments, ethical concerns regarding genetically engineered microorganisms, and equitable access to advanced therapies are critical hurdles that must be addressed. This review underscores the importance of interdisciplinary collaboration and public awareness in overcoming these barriers and ensuring the responsible development of microbiota-based solutions. By leveraging the principles of microbial ecosystems, microbiota biomimetics represents a promising frontier in healthcare and sustainability. This approach has the potential to revolutionize therapeutic strategies, redefine diagnostic tools, and address global challenges, paving the way for a more personalized, efficient, and sustainable future in medicine and biotechnology.

Fucoidan alleviated colitis aggravated by fiber deficiency through protecting the gut barrier, suppressing the MAPK/NF-κB pathway, and modulating gut microbiota and metabolites

Insufficient dietary fiber intake has become a global public health issue, affecting the development and management of various diseases, including intestinal diseases and obesity. This study showed that dietary fiber deficiency enhanced the susceptibility of mice to colitis, which could be attributed to the disruption of the gut barrier integrity, activation of the NF-κB pathway, and oxidative stress. Undaria pinnatifida fucoidan (UPF) alleviated colitis symptoms in mice that fed with a fiber deficient diet (FD), characterized by increased weight gain and reduced disease activity index, liver and spleen indexes, and histological score. The protective effect of UPF against FD-exacerbated colitis can be attributed to the alleviation of oxidative stress, the preservation of the gut barrier integrity, and inhibition of the MAPK/NF-κB pathway. UPF ameliorated the gut microbiota composition, leading to increased microbiota richness, as well as increased levels of Muribaculaceae, Lactobacillaceae, and Bifidobacterium and reduced levels of Proteobacteria, Bacteroidetes, and Bacteroides. Metabolomics analysis revealed that UPF improved the profile of microbiota metabolites, with increased levels of carnitine and taurine and decreased levels of tyrosine and deoxycholic acid. This study suggests that UPF has the potential to be developed as a novel prebiotic agent to enhance human health.

COPD, Dietary Fiber Intake, and Cognitive Performance in Older Adults: A Cross-Sectional Study from NHANES 2011-2014

INTRODUCTION

This study aimed to evaluate the modifying role of dietary fiber intake in the relationship between COPD and cognitive performance.

METHODS

Data of adults aged ≥60 years were extracted from the National Health and Nutrition Examination Survey (NHANES) 2011-2014. Participants with information on cognitive function measures were included. Dietary fiber intake, identified using participants' 24-h recall surveys, was grouped into high (>25 g/day) and low (≤25 g/day) levels. COPD was identified through self-reported physician diagnoses. Associations between dietary fiber intake, cognitive function and COPD were evaluated using the regression analysis.

RESULTS

Data of 2,189 participants were analyzed. Multivariate analysis revealed that COPD was significantly associated with lowered CERAD (adjusted beta [aBeta]: -0.17, 95% confidence interval [CI]: -0.33 to -0.002, p = .047) and DSST (aBeta: -2.23, 95% CI: -4.25 to -0.2, p = .032) scores in older adults. The analysis on the association between COPD and cognitive function stratified by dietary fiber intake revealed that COPD remained significantly associated with lowered CREAD among individuals with a high fiber intake (aBeta: -0.54, 95% CI: -1.00 to -0.08, p = .024).

CONCLUSIONS

In US older adults, COPD is associated with reduced cognitive function. However, the findings do not support that high dietary fiber intake may modify the association between COPD and cognitive impairment.

Targeting Cognitive Resilience through Prebiotics: A Focused Perspective

This perspective article is a product of the work of an expert group within the Prebiotic Task Force convened by the International Life Sciences Institute Europe, a non-profit organization that brings together experts from academia, industry, and public service to catalyze nutrition science for public benefit. An expert group was conceived in October 2023 to discuss the evidence base on the use of prebiotics to promote cognitive functioning, with a focus on highlighting knowledge gaps and proposing a list of recommendations to guide this specific area of research forward. To address this, we evaluated existing systematic reviews and meta-analyses of human intervention studies that examine the effects of prebiotics on cognitive functioning. These are predominantly conducted in healthy participants under basal conditions and have, to date, revealed limited effects. In this perspective, we propose that prebiotics should be investigated as agents to promote cognitive resilience by testing their effects on cognitive performance under certain cognition-taxing factors that individuals encounter across their lifespan. These include stress, poor sleep outcomes, sedentary behavior, and unhealthy dietary patterns, all of which have been shown to be associated with altered microbiome and impact global cognition or specific cognitive domains. In addition, we recommend identifying vulnerable populations that are either subclinical or that struggle chronically or periodically with 1 or more cognition-taxing factors, to better uncover the boundary conditions for prebiotic effectiveness. By broadening the scope of research to include diverse populations and challenging conditions in daily life or experimental settings, we can expand our understanding of the role of prebiotics not only in cognitive health or impairment, but also as potential preventative agents that may promote cognitive resilience during aging and in response to various lifestyle-related challenges.

Phlorizin ameliorates cognitive and behavioral impairments via the microbiota-gut-brain axis in high-fat and high-fructose diet-induced obese male mice

The long-term high-fat, high-sugar diet exacerbates type 2 diabetes mellitus (T2DM)-related cognitive impairments. Phlorizin, a well-studied natural compound found in apples and other plants, is recognized for its bioactive properties, including modulation of glucose and lipid metabolism. Despite its established role in mitigating metabolic disorders, the neuroprotective effects of phlorizin, particularly against diabetes-related cognitive dysfunction, have not been fully elucidated. Therefore, the present study aimed to investigate the effect of dietary supplementation of phlorizin on high-fat and high-fructose diet (HFFD)-induced cognitive dysfunction and evaluate the crucial role of the microbiota-gut-brain axis. We found that dietary supplementation of phlorizin for 14 weeks effectively prevented glucolipid metabolism disorder, spatial learning impairment, and memory impairment in HFFD mice. In addition, phlorizin improved the HFFD-induced decrease in synaptic plasticity, neuroinflammation, and excessive activation of microglia in the hippocampus. Transcriptomics analysis shows that the protective effect of phlorizin on cognitive impairment was associated with increased expression of neurotransmitters and synapse-related genes in the hippocampus. Phlorizin treatment alleviated colon microbiota disturbance, mainly manifested by an increase in gut microbiota diversity and the abundance of short-chain fatty acid (SCFA)-producing bacteria. The level of microbial metabolites, including SCFA, inosine 5'-monophosphate (IMP), and D (-)-beta-hydroxybutyric acid (BHB) were also significantly increased after phlorizin treatment. Integrating multiomics analysis observed tight connections between phlorizin-regulated genes, microbiota, and metabolites. Furthermore, removal of the gut microbiota via antibiotics treatment diminished the protective effect of phlorizin against HFFD-induced cognitive impairment, underscoring the critical role of the gut microbiota in mediating cognitive behavior. Importantly, supplementation with SCFA and BHB alone mimicked the regulatory effects of phlorizin on cognitive function. Therefore, phlorizin shows promise as a potential nutritional therapy for addressing cognitive impairment associated with metabolic disorders. Further research is needed to explore its effectiveness in preventing and alleviating neurodegenerative diseases.

Role of gut microbiota in rheumatoid arthritis: Potential cellular mechanisms regulated by prebiotic, probiotic, and pharmacological interventions

Rheumatoid arthritis (RA) is a chronic autoimmune disease that primarily affects joints and multiple organs and systems, which is long-lasting and challenging to cure and significantly impacting patients' quality of life. Alterations in the composition of intestinal flora in both preclinical and confirmed RA patients indicate that intestinal bacteria play a vital role in RA immune function. However, the mechanism by which the intestinal flora is regulated to improve the condition of RA is not fully understood. This paper reviews the methods of regulating gut microbiota and its metabolites through prebiotics, probiotics, and pharmacological interventions, and discusses their effects on RA. Additionally, it explores the potential predictive role of cellular therapy mechanisms of intestinal flora in treating RA. These findings suggest that restoring the ecological balance of intestinal flora and regulating intestinal barrier function may enhance immune system function, thereby improving rheumatoid arthritis. This offers new insights into its treatment.

A multifactorial lens on risk factors promoting the progression of Alzheimer's disease

The prevalence of Alzheimer's disease (AD) among adults has continued to increase over the last two decades, which has sparked a significant increase in research that focuses on the topic of "brain health." While AD is partially determined by a genetic predisposition, there are still numerous pathophysiological factors that require further research. This research requirement stems from the acknowledgment that AD is a multifactorial disease that to date, cannot be prevented. Therefore, addressing and understanding the potential AD risk factors is necessary to increase the quality of life of an aging population. To raise awareness of critical pathways that impact AD progression, this review manuscript describes AD etiologies, structural impairments, and biomolecular changes that can significantly increase the risk of AD. Among them, a special highlight is given to inflammasomes, which have been shown to bolster neuroinflammation. Alike, the role of brain-derived neurotrophic factor, an essential neuropeptide that promotes the preservation of cognition is presented. In addition, the functional role of neurovascular units to regulate brain health is highlighted and contrasted to inflammatory conditions, such as cellular senescence, vascular damage, and increased visceral adiposity, who all increase the risk of neuroinflammation. Altogether, a multifactorial interventional approach is warranted to reduce the risk of AD.

Microbiota-Gut-Brain Axis in Age-Related Neurodegenerative Diseases

BACKGROUND

Age-related neurodegenerative diseases (NDs) pose a formidable challenge to healthcare systems worldwide due to their complex pathogenesis, significant morbidity, and mortality. Scope and Approach: This comprehensive review aims to elucidate the central role of the microbiotagut- brain axis (MGBA) in ND pathogenesis. Specifically, it delves into the perturbations within the gut microbiota and its metabolomic landscape, as well as the structural and functional transformations of the gastrointestinal and blood-brain barrier interfaces in ND patients. Additionally, it provides a comprehensive overview of the recent advancements in medicinal and dietary interventions tailored to modulate the MGBA for ND therapy.

CONCLUSION

Accumulating evidence underscores the pivotal role of the gut microbiota in ND pathogenesis through the MGBA. Dysbiosis of the gut microbiota and associated metabolites instigate structural modifications and augmented permeability of both the gastrointestinal barrier and the blood-brain barrier (BBB). These alterations facilitate the transit of microbial molecules from the gut to the brain via neural, endocrine, and immune pathways, potentially contributing to the etiology of NDs. Numerous investigational strategies, encompassing prebiotic and probiotic interventions, pharmaceutical trials, and dietary adaptations, are actively explored to harness the microbiota for ND treatment. This work endeavors to enhance our comprehension of the intricate mechanisms underpinning ND pathogenesis, offering valuable insights for the development of innovative therapeutic modalities targeting these debilitating disorders.

Maternal Gut Microbiome-Mediated Epigenetic Modifications in Cognitive Development and Impairments: A New Frontier for Therapeutic Innovation

Cognitive impairment in various mental illnesses, particularly neuropsychiatric disorders, has adverse functional and clinical consequences. While genetic mutations and epigenetic dysregulations of several genes during embryonic and adult periods are linked to cognitive impairment in mental disorders, the composition and diversity of resident bacteria in the gastrointestinal tract-shaped by environmental factors-also influence the brain epigenome, affecting behavior and cognitive functions. Accordingly, many recent studies have provided evidence that human gut microbiota may offer a potential avenue for improving cognitive deficits. In this review, we provide an overview of the relationship between cognitive impairment, alterations in the gut microbiome, and epigenetic alterations during embryonic and adult periods. We examine how various factors beyond genetics-such as lifestyle, age, and maternal diet-impact the composition, diversity, and epigenetic functionality of the gut microbiome, consequently influencing cognitive performance. Additionally, we explore the potential of maternal gut microbiome signatures and epigenetic biomarkers for predicting cognitive impairment risk in older adults. This article also explores the potential roles of nutritional deficiencies in programming cognitive disorders during the perinatal period in offspring, as well as the promise of gut microbiome-targeted therapeutics with epigenetic effects to prevent or alleviate cognitive dysfunctions in infants, middle-aged adults, and older adults. Unsolved challenges of gut microbiome-targeted therapeutics in mitigating cognitive dysfunctions for translation into clinical practice are discussed, lastly.

Current perspectives on microglia-neuron communication in the central nervous system: Direct and indirect modes of interaction

BACKGROUND

The incessant communication that takes place between microglia and neurons is essential the development, maintenance, and pathogenesis of the central nervous system (CNS). As mobile phagocytic cells, microglia serve a critical role in surveilling and scavenging the neuronal milieu to uphold homeostasis.

AIM OF REVIEW

This review aims to discuss the various mechanisms that govern the interaction between microglia and neurons, from the molecular to the organ system level, and to highlight the importance of these interactions in the development, maintenance, and pathogenesis of the CNS.

KEY SCIENTIFIC CONCEPTS OF REVIEW

Recent research has revealed that microglia-neuron interaction is vital for regulating fundamental neuronal functions, such as synaptic pruning, axonal remodeling, and neurogenesis. The review will elucidate the intricate signaling pathways involved in these interactions, both direct and indirect, to provide a better understanding of the fundamental mechanisms of brain function. Furthermore, gaining insights into these signals could lead to the development of innovative therapies for neural disorders.

Neuroprotective Effect of a Multistrain Probiotic Mixture in SOD1G93A Mice by Reducing SOD1 Aggregation and Targeting the Microbiota-Gut-Brain Axis

Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease characterized by the selective loss of motor neurons. A bidirectional communication system known as the "microbiota-gut-brain" axis has a regulatory function in neurodegenerative disorders. The impact of probiotics on ALS through the "microbiota-gut-brain" axis remains uncertain. A longitudinal investigation was conducted to examine the alterations in the structure of the ileum and colon in mutant superoxide dismutase 1 (SOD1G93A) transgenic mice models of ALS by using immunofluorescence and Western blotting. Subsequently, the mice were administered a multistrain probiotic mixture (LBE) or vehicle orally, starting from 60 days of age until the terminal stage of the disease. The effects of these agents on the behavior, gut microbiota, microbial metabolites, and pathological processes of the spinal and intestine of SOD1G93A mice were analyzed, with a focus on exploring potential protective mechanisms. SOD1G93A mice exhibit various structural abnormalities in the intestine. Oral administration of LBE improved the proinflammatory response, reduced aberrant superoxide dismutase 1 (SOD1) aggregation, and protected neuronal cells in the intestine and spinal cord of SOD1G93A mice. Furthermore, LBE treatment resulted in a change in intestinal microbiota, an increase in short-chain fatty acid levels, and an enhancement in autophagy flux. SOD1G93A mice exhibited various structural abnormalities in the intestine. LBE can improve the proinflammatory response, reduce aberrant SOD1 aggregation, and protect neuronal cells in the spinal cord and intestine of SOD1G93A mice. The positive effect of LBE can be attributed to increased short-chain fatty acids and enhanced autophagy flux.

Inhibitory effect of tea flower polysaccharides on oxidative stress and microglial oxidative damage in aging mice by regulating gut microbiota

Tea flower polysaccharides (TFPS) have prominent anti-aging effect. In this study, we used an animal model of aging induced by D-galactose in mice to investigate the effect of TFPS on reducing inflammatory factors, lowering oxidative stress levels, and inhibiting oxidative damage to microglia from the perspective of regulating gut microbiota. The results showed that TFPS could improve the homeostasis of gut microbiota in aging mice, reduce the ratio of Firmicutes to Bacteroidota, and significantly increase the abundance of Lactobacillus. At the same time, TFPS reduced the excessive activation of hippocampal microglia in aging mice, significantly down-regulated the levels of pro-inflammatory factors IL-6, IL-1β, TNF-α, and nuclear transcription factor NF-κB, increased the activity of antioxidant enzymes SOD, CAT, and POD, and reduced the content of MDA. Our research results indicate that TFPS can improve the disorder of gut microbiota, alleviate oxidative damage to glial cells, alleviate neuroinflammation, and play a role in delaying aging.

Succinate exacerbates mastitis in mice via extracellular vesicles derived from the gut microbiota: a potential new mechanism for mastitis

BACKGROUND

A high grain diet causes an ecological imbalance in the gut microbiota and serves as an important endogenous trigger of mastitis in dairy cows, but the underlying mechanisms are unclear. Our previous study revealed that subacute rumen acidosis (SARA)-associated mastitis has distinct metabolic profiles in the rumen, especially a significant increase in succinate, but the role of succinate in the pathogenesis of mastitis remains unclear.

RESULTS

Succinate treatment exacerbates low-grade endotoxemia-induced mastitis in mice. Specifically, succinate increased the production of gut microbiota-extracellular vehicles (mEVs) containing lipopolysaccharides, which can diffuse across the damaged intestinal barrier into the mammary glands. Administration of mEVs promotes mammary inflammation via activation of the TLR4/NF-κB pathway.

CONCLUSIONS

Our findings suggest that succinate promotes mastitis through the proliferation of enteric pathogens and mEVs production, suggesting a potential strategy for mastitis intervention on the basis of intestinal metabolic regulation and pathogen inhibition. The role of mEVs in interspecific communication has also been elucidated.

Diethyl butylmalonate attenuates cognitive deficits and depression in 5×FAD mice

Background

Alzheimer's disease (AD), characterized by cognitive impairment and depression, is currently one of the intractable problems due to the insufficiency of intervention strategies. Diethyl butylmalonate (DBM) has recently attracted extensive interest due to its anti-inflammatory role in macrophages. However, it is still unknown whether DBM has a beneficial effect on cognitive deficits and depression.

Methods

DBM was administrated to 5×FAD and C57BL/6J mice by intraperitoneal injection. Novel object recognition, Y-maze spatial memory, Morris water maze and nest building tests were used to evaluate cognitive function. Moreover, the tail suspension test, forced swimming test, open field test and the elevated plus maze test were used to assess depression. Transmission electron microscopy, Golgi-Cox staining, immunofluorescence, RT-qPCR and western blot were utilized to determine the neuropathological changes in the hippocampus and amygdala of mice.

Results

Multiple behavioral tests showed that DBM effectively mitigated cognitive deficit and depression in 5×FAD mice. Moreover, DBM significantly attenuated synaptic ultrastructure and neurite impairment in the hippocampus of 5×FAD mice, paralleled by the improvement of the deficits of PSD95 and BDNF proteins. In addition, DBM decreased the accumulation of microglia and downregulated neuroinflammation in the hippocampus and amygdala of 5×FAD mice.

Conclusion

This study provides evidence that DBM ameliorates cognitive deficits and depression via improvement of the impairment of synaptic ultrastructure and neuroinflammation, suggesting that DBM is a potential drug candidate for treating AD-related neurodegeneration.

Gut microbiota modulates depressive-like behaviors induced by chronic ethanol exposure through short-chain fatty acids

BACKGROUND

Chronic ethanol exposure (CEE) is recognized as an important risk factor for depression, and the gut-brain axis has emerged as a key mechanism underlying chronic ethanol exposure-induced anxiety and depression-like behaviors. Short-chain fatty acids (SCFAs), which are the key metabolites generated by gut microbiota from insoluble dietary fiber, exert protective roles on the central nervous system, including the reduction of neuroinflammation. However, the link between gut microbial disturbances caused by chronic ethanol exposure, production of SCFAs, and anxiety and depression-like behaviors remains unclear.

METHODS

Initially, a 90-day chronic ethanol exposure model was established, followed by fecal microbiota transplantation model, which was supplemented with SCFAs via gavage. Anxiety and depression-like behaviors were determined by open field test, forced swim test, and elevated plus-maze. Serum and intestinal SCFAs levels were quantified using GC-MS. Changes in related indicators, including the intestinal barrier, intestinal inflammation, neuroinflammation, neurotrophy, and nerve damage, were detected using Western blotting, immunofluorescence, and Nissl staining.

RESULTS

Chronic ethanol exposure disrupted with gut microbial homeostasis, reduced the production of SCFAs, and led to anxiety and depression-like behaviors. Recipient mice transplanted with fecal microbiota that had been affected by chronic ethanol exposure exhibited impaired intestinal structure and function, low levels of SCFAs, intestinal inflammation, activation of neuroinflammation, a compromised blood-brain barrier, neurotrophic defects, alterations in the GABA system, anxiety and depression-like behaviors. Notably, the negative effects observed in these recipient mice were significantly alleviated through the supplementation of SCFAs.

CONCLUSION

SCFAs not only mitigate damage to intestinal structure and function but also alleviate various lesions in the central nervous system, such as neuroinflammation, and reduce anxiety and depression-like behaviors, which were triggered by transplantation with fecal microbiota that had been affected by chronic ethanol exposure, adding more support that SCFAs serve as a bridge between the gut and the brain.

Microglia and gut microbiota: A double-edged sword in Alzheimer's disease

The strong association between gut microbiota (GM) and brain functions such as mood, behaviour, and cognition has been well documented. Gut-brain axis is a unique bidirectional communication system between the gut and brain, in which gut microbes play essential role in maintaining various molecular and cellular processes. GM interacts with the brain through various pathways and processes including, metabolites, vagus nerve, HPA axis, endocrine system, and immune system to maintain brain homeostasis. GM dysbiosis, or an imbalance in GM, is associated with several neurological disorders, including anxiety, depression, and Alzheimer's disease (AD). Conversely, AD is sustained by microglia-mediated neuroinflammation and neurodegeneration. Further, GM and their products also affect microglia-mediated neuroinflammation and neurodegeneration. Despite the evidence connecting GM dysbiosis and AD progression, the involvement of GM in modulating microglia-mediated neuroinflammation in AD remains elusive. Importantly, deciphering the mechanism/s by which GM regulates microglia-dependent neuroinflammation may be helpful in devising potential therapeutic strategies to mitigate AD. Herein, we review the current evidence regarding the involvement of GM dysbiosis in microglia activation and neuroinflammation in AD. We also discuss the possible mechanisms through which GM influences the functioning of microglia and its implications for therapeutic intervention. Further, we explore the potential of microbiota-targeted interventions, such as prebiotics, probiotics, faecal microbiota transplantation, etc., as a novel therapeutic strategy to mitigate neuroinflammation and AD progression. By understanding and exploring the gut-brain axis, we aspire to revolutionize the treatment of neurodegenerative disorders, many of which share a common theme of microglia-mediated neuroinflammation and neurodegeneration.

Implications of the Gut Microbiome in Alzheimer's Disease: A Narrative Review

Alzheimer's disease (AD) is a progressive neurodegenerative disorder, with its prevalence doubling approximately every decade. It is a significant contributor to disability-adjusted life-years in individuals aged 50 and older, impacting a substantial portion of this population globally. The pathophysiology of AD is primarily explained by two hypotheses: the amyloid cascade hypothesis and the tau hypothesis. While the amyloid cascade hypothesis is widely accepted as the main contributor to AD, both mechanisms promote neuroinflammation by driving the formation of amyloid-beta (Aβ) plaques and tau tangles, which are key features of the neurodegenerative process. Recent studies highlight the critical role of the gut microbiome (GMB) in the progression of AD. Gut dysbiosis has been linked to neuroinflammation, altered Aβ metabolism, blood-brain barrier disruption, and changes in neuroactive metabolites. Targeting the GMB offers potential therapeutic avenues aimed at restoring microbial balance and mitigating the effects of dysbiosis. The gut-brain axis, crucial for neurological health, remains underexplored in AD, especially since current research is limited to animal models and small human studies, leaving uncertainty about specific gut bacteria's roles in AD. Currently, pharmacological treatments for AD include cholinesterase inhibitors and memantine. This review discusses newer and emerging treatments targeting Aβ and tau pathology, alongside microbiome-based interventions. Larger, human-based studies with diverse populations are essential to establish the therapeutic efficacy of these microbiome-targeted treatments and their long-term impact on AD management.

UDCA ameliorates inflammation driven EMT by inducing TGR5 dependent SOCS1 expression in mouse macrophages

Long-standing chronic inflammation of the digestive tract leads to Inflammatory Bowel Diseases (IBD), comprising Crohn's Disease (CD) and Ulcerative colitis (UC). The persistent prevalence of these conditions in the gut is a predisposing factor for Colitis-Associated Cancer (CAC), one of the most common sub-types of Colorectal Cancer (CRC), emphasizing the role of inflammation in tumorigenesis. Therefore, targeted intervention of chronic intestinal inflammation is a potential strategy for preclusion and treatment of inflammation-driven malignancies. The association between bile acids (BA) and gut immune homeostasis has been explored in the recent past. However, the exact downstream mechanism by which secondary BA successfully regulating intestinal inflammation and inflammation-dependent CAC is unclear. Our study demonstrated that Ursodeoxycholic acid (UDCA), a secondary bile acid of host gut microbial origin, finetunes the dialogue between activated macrophages and intestinal epithelial cells, modulating inflammation-driven epithelial-mesenchymal transition (EMT), a hallmark of cancer. UDCA treatment and dependency on the TGR5/GPBAR1 receptor significantly upregulated the Suppressor of Cytokine Signaling 1 (SOCS1) expression, contributing to the regulation of pro-inflammatory cytokines in activated macrophages. In this study, we also noticed heightened expression of SOCS1 in UDCA-mitigated CAC in the AOM-DSS mouse model with reduced inflammatory gene expression. Overall, our observations highlight the possible utility of UDCA for inflammation-driven intestinal cancer.

Refined diet consumption increases neuroinflammatory signalling through bile acid dysmetabolism

Over recent decades, dietary patterns have changed significantly due to the increasing availability of convenient, ultra-processed refined foods. Refined foods are commonly depleted of key bioactive compounds, which have been associated with several deleterious health conditions. As the gut microbiome can influence the brain through a bidirectional communication system known as the 'microbiota-gut-brain axis', the consumption of refined foods has the potential to affect cognitive health. In this study, multi-omics approaches were employed to assess the effect of a refined diet on the microbiota-gut-brain axis, with a particular focus on bile acid metabolism. Mice maintained on a refined low-fat diet (rLFD), consisting of high sucrose, processed carbohydrates and low fibre content, for eight weeks displayed significant gut microbial dysbiosis, as indicated by diminished alpha diversity metrics (p < 0.05) and altered beta diversity (p < 0.05) when compared to mice receiving a chow diet. Changes in gut microbiota composition paralleled modulation of the metabolome, including a significant reduction in short-chain fatty acids (acetate, propionate and n-butyrate; p < 0.001) and alterations in bile acid concentrations. Interestingly, the rLFD led to dysregulated bile acid concentrations across both the colon (p < 0.05) and the brain (p < 0.05) which coincided with altered neuroinflammatory gene expression. In particular, the concentration of TCA, TDCA and T-α-MCA was inversely correlated with the expression of NF-κB1, a key transcription factor in neuroinflammation. Overall, our results suggest a novel link between a refined low-fat diet and detrimental neuronal processes, likely in part through modulation of the microbiota-gut-brain axis and bile acid dysmetabolism.

Short-chain fatty acid on blood-brain barrier and glial function in ischemic stroke

Stroke is the second most common cause of death and one of the most common causes of disability worldwide. The intestine is home to several microorganisms that fulfill essential functions for the natural and physiological functioning of the human body. There is an interaction between the central nervous system (CNS) and the gastrointestinal system that enables bidirectional communication between them, the so-called gut-brain axis. Based on the gut-brain axis, there is evidence of a link between the gut microbiota and the regulation of microglial functions through glial activation. This interaction is partly due to the immunological properties of the microbiota and its connection with the CNS, such that metabolites produced by the microbiota can cross the gut barrier, enter the bloodstream and reach the CNS and significantly affect microglia, astrocytes and other cells of the immune system. Studies addressing the effects of short-chain fatty acids (SCFAs) on glial function and the BBB in ischemic stroke are still scarce. Therefore, this review aims to stimulate the investigation of these associations, as well as to generate new studies on this topic that can clarify the role of SCFAs after stroke in a more robust manner.

Explore the mechanisms of triterpenoids from Ganoderma lucidum in the protection against Alzheimer's disease via microbiota-gut-brain axis with the aid of network pharmacology

Ganoderma lucidum (Curtis) P. Karst.(G. lucidum) is a kind of fungi, which also a traditional Chinese medicine used for "wisdom growth" in China. Triterpenoids from G. lucidum (GLTs) are one of the main active ingredients. Based on the strategy of early intervention on Alzheimer's disease (AD) and the inextricable association between disordered gut microbiota and metabolites with AD, this study aimed to explore the mechanisms of GLTs in the protection against AD via microbiota-gut-brain axis with the aid of network pharmacology. In this study, LC-MS/MS was used to identify the main active ingredients of GLTs. Network pharmacology was used to predict the potential target and validated with Caco-2 cell model. D-galactose was used to induce the slow-onset AD on rats. Metabolomics methods basing on GC-MS combined with 16S rRNA sequencing technology was used to carry out microbiota-gut-metabolomics analysis in order to reveal the potential mechanisms of GLTs in the protection of AD. As results, GLTs showed a protection against AD effect on rats by intervening administration. The mechanisms were inextricably linked to GLTs interference with the balance of gut microbiota and metabolites. The main fecal metabolites involved were short-chain fatty acids and aromatic amino acid metabolites.

Gut microbiome predicts cognitive function and depressive symptoms in late life

Depression in older adults with cognitive impairment increases progression to dementia. Microbiota is associated with current mood and cognition, but the extent to which it predicts future symptoms is unknown. In this work, we identified microbial features that reflect current and predict future cognitive and depressive symptoms. Clinical assessments and stool samples were collected from 268 participants with varying cognitive and depressive symptoms. Seventy participants underwent 2-year follow-up. Microbial community diversity, structure, and composition were assessed using high-resolution 16 S rRNA marker gene sequencing. We implemented linear regression to characterize the relationship between microbiome composition, current cognitive impairment, and depressive symptoms. We leveraged elastic net regression to discover features that reflect current or future cognitive function and depressive symptoms. Greater microbial community diversity associated with lower current cognition in the whole sample, and greater depression in participants not on antidepressants. Poor current cognitive function associated with lower relative abundance of Bifidobacterium, while greater GABA degradation associated with greater current depression severity. Future cognitive decline associated with lower cognitive function, lower relative abundance of Intestinibacter, lower glutamate degradation, and higher baseline histamine synthesis. Future increase in depressive symptoms associated with higher baseline depression and anxiety, lower cognitive function, diabetes, lower relative abundance of Bacteroidota, and lower glutamate degradation. Our results suggest cognitive dysfunction and depression are unique states with an overall biological effect detectable through gut microbiota. The microbiome may present a noninvasive readout and prognostic tool for cognitive and psychiatric states.

Gut microbiota metabolites: potential therapeutic targets for Alzheimer's disease?

Background

Alzheimer's disease (AD) is a neurodegenerative disease characterized by progressive decline in cognitive function, which significantly increases pain and social burden. However, few therapeutic interventions are effective in preventing or mitigating the progression of AD. An increasing number of recent studies support the hypothesis that the gut microbiome and its metabolites may be associated with upstream regulators of AD pathology.

Methods

In this review, we comprehensively explore the potential mechanisms and currently available interventions targeting the microbiome for the improvement of AD. Our discussion is structured around modern research advancements in AD, the bidirectional communication between the gut and brain, the multi-target regulatory effects of microbial metabolites on AD, and therapeutic strategies aimed at modulating gut microbiota to manage AD.

Results

The gut microbiota plays a crucial role in the pathogenesis of AD through continuous bidirectional communication via the microbiota-gut-brain axis. Among these, microbial metabolites such as lipids, amino acids, bile acids and neurotransmitters, especially sphingolipids and phospholipids, may serve as central components of the gut-brain axis, regulating AD-related pathogenic mechanisms including β-amyloid metabolism, Tau protein phosphorylation, and neuroinflammation. Additionally, interventions such as probiotic administration, fecal microbiota transplantation, and antibiotic use have also provided evidence supporting the association between gut microbiota and AD. At the same time, we propose an innovative strategy for treating AD: a healthy lifestyle combined with targeted probiotics and other potential therapeutic interventions, aiming to restore intestinal ecology and microbiota balance.

Conclusion

Despite previous efforts, the molecular mechanisms by which gut microbes act on AD have yet to be fully described. However, intestinal microorganisms may become an essential target for connecting the gut-brain axis and improving the symptoms of AD. At the same time, it requires joint exploration by multiple centers and multiple disciplines.

Preoperative gut microbiota of POCD patients induces pre- and postoperative cognitive impairment and systemic inflammation in rats

BACKGROUND

Postoperative cognitive dysfunction (POCD) is common following surgery in elderly patients. The role of the preoperative gut microbiota in POCD has attracted increasing attention, but the potential underlying mechanisms remain unclear. This research aimed to investigate the impact of the preoperative gut microbiota on POCD.

METHODS

Herein, we analyzed the preoperative gut microbiota of POCD patients through a prospective specimen collection and retrospective blinded evaluation study. Then, we transferred the preoperative gut microbiota of POCD patients to antibiotic-treated rats and established POCD model by abdominal surgery to explore the impact of the preoperative gut microbiota on pre- and postoperative cognitive function and systemic inflammation. The gut microbiota was analyzed using 16S rRNA sequencing analysis. The Morris water maze test was performed to evaluate learning and memory abilities. The inflammatory cytokines TNF-α, IL-1β and IL-6 in the serum and hippocampus were measured by ELISA. Microglia were examined by immunofluorescence staining for Iba-1.

RESULTS

Based on the decrease in the postoperative MMSE score, 24 patients were identified as having POCD and were matched with 24 control patients. Compared with control patients, POCD patients exhibited higher BMI and lower preoperative MMSE score. The preoperative gut microbiota of POCD patients had lower bacterial richness but a larger distribution, decreased abundance of Firmicutes and increased abundance of Proteobacteria than did that of control patients. Compared with rats that received preoperative fecal samples of control patients, rats that received preoperative fecal samples of POCD patients presented an increased abundance of Desulfobacterota, decreased cognitive function, increased levels of TNF-α and IL-1β in the serum, increased levels of TNF-α and greater microglial activation in the hippocampus. Additionally, correlation analysis revealed a positive association between the abundance of Desulfobacterota and the level of serum TNF-α in rats. Then, we performed abdominal surgery to investigate the impact of the preoperative gut microbiota on postoperative conditions, and the surgery did indeed cause POCD and inflammatory response. Notably, compared with rats that received preoperative fecal samples of control patients, rats that received preoperative fecal samples of POCD patients displayed exacerbated cognitive impairment; increased levels of TNF-α, IL-1β and IL-6 in the serum and hippocampus; and increased activation of microglia in the hippocampus.

CONCLUSIONS

Our findings suggest that the preoperative gut microbiota of POCD patients can induce preoperative and aggravate postoperative cognitive impairment and systemic inflammation in rats. Modulating inflammation by targeting the gut microbiota might be a promising approach for preventing POCD.

The communication mechanism of the gut-brain axis and its effect on central nervous system diseases: A systematic review

Gut microbiota is involved in intricate and active metabolic processes the host's brain function, especially its role in immune responses, secondary metabolism, and symbiotic connections with the host. Gut microbiota can promote the production of essential metabolites, neurotransmitters, and other neuroactive chemicals that affect the development and treatment of central nervous system diseases. This article introduces the relevant pathways and manners of the communication between the brain and gut, summarizes a comprehensive overview of the current research status of key gut microbiota metabolites that affect the functions of the nervous system, revealing those adverse factors that affect typical communication between the brain-gut axis, and outlining the efforts made by researchers to alleviate these neurological diseases through targeted microbial interventions. The relevant pathways and manners of communication between the brain and gut contribute to the experimental design of new treatment plans and drug development. The factors that may cause changes in gut microbiota and affect metabolites, as well as current intervention methods are summarized, which helps improve gut microbiota brain dialogue, prevent adverse triggering factors from interfering with the gut microbiota system, and minimize neuropathological changes.

Nutritional strategies modulating the gut microbiome as a preventative and therapeutic approach in normal and pathological age-related cognitive decline: a systematic review of preclinical and clinical findings

CONTEXT

The proportion of the elderly population is on the rise across the globe, and with it the prevalence of age-related neurodegenerative diseases. The gut microbiota, whose composition is highly regulated by dietary intake, has emerged as an exciting research field in neurology due to its pivotal role in modulating brain functions via the gut-brain axis.

OBJECTIVES

We aimed at conducting a systematic review of preclinical and clinical studies investigating the effects of dietary interventions on cognitive ageing in conjunction with changes in gut microbiota composition and functionality.

METHODS

PubMed and Scopus were searched using terms related to ageing, cognition, gut microbiota and dietary interventions. Studies were screened, selected based on previously determined inclusion and exclusion criteria, and evaluated for methodological quality using recommended risk of bias assessment tools.

RESULTS

A total of 32 studies (18 preclinical and 14 clinical) were selected for inclusion. We found that most of the animal studies showed significant positive intervention effects on cognitive behavior, while outcomes on cognition, microbiome features, and health parameters in humans were less pronounced. The effectiveness of dietary interventions depended markedly on the age, gender, degree of cognitive decline and baseline microbiome composition of participants.

CONCLUSION

To harness the full potential of microbiome-inspired nutrition for cognitive health, one of the main challenges remains to better understand the interplay between host, his microbiome, dietary exposures, whilst also taking into account environmental influences. Future research should aim toward making use of host-specific microbiome data to guide the development of personalized therapies.