Gut-brain axis: A cutting-edge approach to target neurological disorders and potential synbiotic application

Impact of prophages on gut microbiota and disease associations

The gut microbiota plays an important role in maintaining host health by affecting various physiological functions. Among the diverse microbial communities in the gut, prophages are integral components of bacterial genomes, contributing significantly to bacterial evolution, ecology and pathogenicity. Prophages are capable of switching to lytic cycles in response to various internal and external factors. Factors that induce prophage induction include DNA damage, oxidative stress, nutrient availability, host immune response, quorum sensing, diet, secondary metabolites, antibiotics, and lifestyle changes. Prophage induction could contribute to both gut homeostasis and dysbiosis. Importantly, the connections between prophage induction and disorders such as inflammatory bowel disease, ulcerative colitis, and bacterial vaginosis highlight the dual roles of prophages in both health and disease. Although therapeutic approaches such as phage therapy (PT), fecal microbiota transplants (FMT), and fecal virome transplants (FVT) have gained attention, the concept of dietary prophage induction therapy offers a novel, targeted method to modulate gut microbiota. In spite of recent advances in understanding the role of prophages in gut health, the exact mechanisms by which they influence gut health remain only partially understood. Therefore, further research is needed to elucidate additional molecular mechanisms of prophage induction pathways and to explore their implications for gut microbiota dynamics and disease associations. This review discusses the molecular mechanisms and key factors that trigger prophage induction in the gut. Insights into these processes could lead to innovative therapeutic strategies that utilize prophages to support gut health.

Unraveling the nutritional challenges in epilepsy: Risks, deficiencies, and management strategies: A systematic review

BACKGROUND

Malnutrition and epilepsy share a complex bidirectional relationship, with malnutrition serving as a potential risk factor for epilepsy development, while epilepsy, in turn, often exerts profound effects on nutritional status. Nutritional interventions have emerged as a critical adjunctive approach in epilepsy management.

AIM

To explore the multifaceted associations between malnutrition and epilepsy, structured into three primary sections: (1) Elucidating the impact of malnutrition as a risk factor for epilepsy onset; (2) Examining the reciprocal influence of epilepsy on nutritional status, and (3) Evaluating diverse nutritional interventions in the management of epilepsy.

METHODS

A systematic search was conducted across PubMed, Scopus, and Web of Science databases utilizing defined keywords related to malnutrition, epilepsy, and nutritional interventions. Inclusion criteria encompassed various study types, including clinical trials, animal models, cohort studies, case reports, meta-analyses, systematic reviews, guidelines, editorials, and review articles. Four hundred sixteen pertinent references were identified, with 198 review articles, 153 research studies, 21 case reports, 24 meta-analyses, 14 systematic reviews, 4 guidelines, and 2 editorials meeting the predefined criteria.

RESULTS

The review revealed the intricate interplay between malnutrition and epilepsy, highlighting malnutrition as a potential risk factor in epilepsy development and elucidating how epilepsy often leads to nutritional deficiencies. Findings underscored the importance of nutritional interventions in managing epilepsy, showing their impact on seizure frequency, neuronal function, and overall brain health.

CONCLUSION

This systematic review emphasizes the bidirectional relationship between malnutrition and epilepsy while emphasizing the critical role of nutritional management in epilepsy treatment. The multifaceted insights underscore the need for a holistic approach to addressing nutritional aspects alongside conventional epilepsy management strategies.

Longer-term effects and underlying mechanisms of dietary intervention strategies on cognitive performance in adults with cognitive impairment

PURPOSE OF REVIEW

As global life expectancy increases, age-related neurodegenerative conditions such as dementia impose an increasing public health and socioeconomic burden. Maintaining a healthy lifestyle, particularly through a healthy diet, may reduce cognitive decline and support cognitive performance in aging populations. Despite increasing interest in dietary interventions as a strategy to enhance cognitive performance, research findings remain inconclusive. This narrative review aims to synthesize evidence on the longer-term effects (published February 2023-October 2024) and underlying mechanisms of dietary intervention strategies on cognitive performance in adults with preexisting cognitive impairment.

RECENT FINDINGS

Recent evidence from randomized controlled trials suggests that both single- and multifactor dietary interventions may improve one or more cognitive domains in aging adults with preexisting cognitive impairment. However, variability in intervention types, durations, and participant characteristics limits the ability to draw definitive conclusions.

SUMMARY

This review highlights the potential benefits of longer-term dietary interventions on cognitive performance in adults with cognitive impairment. It further integrates emerging mechanistic insights, suggesting that specific dietary components may exert neuroprotective effects primarily by reducing oxidative stress and neuroinflammation, and by enhancing brain vascular function. These mechanisms may promote neuroplasticity through the modulation of neurotrophic signaling pathways. Future research should focus on replicating these findings to validate their efficacy and the underlying mechanisms involved. This is essential for integrating dietary approaches into evidence-based guidelines for promoting long-term cognitive health.

Underestimated virus impaired cognition-more evidence and more work to do

Neurodegenerative disorders (NDs) are chronic neurological diseases that can be of idiopathic, genetic, or potentially infectious origin. Although the exact cause of neurodegeneration is unknown, it might be result of a confluence of age, genetic susceptibility factors, and environmental stresses. The blood-brain barrier shields the brain from the majority of viral infections, however neurotropic viruses are able to breach this barrier and infect central nervous system. Growing research points to a possible connection between viruses and neurodegenerative diseases, indicating that virus-induced neuroinflammation and disruption of neuronal protein quality control may play a role in the initial stages of disease progression. The diagnosis and treatment of NDs are urgent and challenging. Even though there is limited clinical evidence to support the use of antiviral medications and their dose regimens within the central nervous system (CNS), with the exception of acyclovir, they are currently utilized to treat various viral CNS infections. Understanding the neuropathogenesis of viral CNS infection may help with targeted diagnosis and treatment plans by focusing on the molecular mechanisms of the CNS. It may also be helpful in the search for new antiviral drugs, which are crucial for better managing these neurotropic viral infections. This review focuses on new findings linking viral infection to NDs and explores how viral modifications of cellular functions can impact the development of neurodegeneration and will also explore the therapeutic potential of antiviral drugs in NDs.

Neuroprotective effect of Thymus vulgaris on paraquat induced Parkinson's disease

The dramatic surge of neurodegenerative disorders among elderly population underscore the pressing demand for development of optimal and evidence based noninvasive natural treatment strategies. Paraquat exposure in animal models used in scientific studies can cause a variety of clinical signs of Parkinson disease (PD). The health benefits of thyme include antioxidant, anti-inflammatory, pulmonary, and neurological benefits. Thyme and other herbal treatments are frequently used to treat a variety of conditions, including neurological issues. The primary factor in the etiology of neurodegeneration is oxidative stress. Conventional treatments are indicated to potentially have negative side effects. The primary phytochemicals of Thymus vulgaris (TV), which are responsible for its unique therapeutic property of neuro-protection, include hydrocarbon and phenolic compounds like thymol and carvacrol. The goal of the current investigation was to examine T. vulgaris' potential for neuroprotection while also ensuring its safety. Analyses of the plant's physicochemical and phytochemical composition were performed by liquid chromatographic analysis. Neuro-behavioral and biochemical parameters were evaluated to determine the impact of T. vulgaris in paraquat induced parkinsonian rodents model. The neurobehavioral tests include open field tests for movement and exploration, Y maze test and elevated plus maze test for natural behavior, memory, and anxiety, hole board tests for exploratory behavior, ladder climbing, foot printing, and wire hanging tests for estimating neuromuscular coordination. T. vulgaris treatment significantly improved neurobehavioral parameters dose-dependently, Biochemical analysis revealed that extract treatment mitigated the declined level of antioxidant enzymes. RT-PCR analysis showed that in paraquat treated group mRNA expression of IL-1α, IL-1β, Alpha-Synuclein, TNF-α, and IL-6 was upregulated markedly. However, T. vulgaris treatment dose dependently down-regulated the mRNA expression of these genes. The groundbreaking results of current study revealed that T. vulgaris restored the degenerative alterations, neuro-inflammation, and nerve loss in the brain structure, as evident by histopathological investigation. Particularly remarkable restoration in neuropsychological and biochemical markers emphasize the medicinal potential of T. vulgaris as a revolutionary treatment for neurodegenerative disorders, offering new hope for millions worldwide afflicted by these devastating conditions.

Could a Mediterranean Diet Modulate Alzheimer's Disease Progression? The Role of Gut Microbiota and Metabolite Signatures in Neurodegeneration

Neurodegenerative disorders such as Alzheimer's disease (AD), the most common form of dementia, represent a growing global health crisis, yet current treatment strategies remain primarily palliative. Recent studies have shown that neurodegeneration through complex interactions within the gut-brain axis largely depends on the gut microbiota and its metabolites. This review explores the intricate molecular mechanisms linking gut microbiota dysbiosis to cognitive decline, emphasizing the impact of microbial metabolites, including short-chain fatty acids (SCFAs), bile acids, and tryptophan metabolites, on neuroinflammation, blood-brain barrier (BBB) integrity, and amyloid-β and tau pathology. The paper highlights major microbiome signatures associated with Alzheimer's disease, detailing their metabolic pathways and inflammatory crosstalk. Dietary interventions have shown promise in modulating gut microbiota composition, potentially mitigating neurodegenerative processes. This review critically examines the influence of dietary patterns, such as the Mediterranean and Western diets, on microbiota-mediated neuroprotection. Bioactive compounds like prebiotics, omega-3 fatty acids, and polyphenols exhibit neuroprotective effects by modulating gut microbiota and reducing neuroinflammation. Furthermore, it discusses emerging microbiome-based therapeutic strategies, including probiotics, prebiotics, postbiotics, and fecal microbiota transplantation (FMT), as potential interventions for slowing Alzheimer's progression. Despite these advances, several knowledge gaps remain, including interindividual variability in microbiome responses to dietary interventions and the need for large-scale, longitudinal studies. The study proposes an integrative, precision medicine approach, incorporating microbiome science into Alzheimer's treatment paradigms. Ultimately, cognizance of the gut-brain axis at a mechanistic level could unlock novel therapeutic avenues, offering a non-invasive, diet-based strategy for managing neurodegeneration and improving cognitive health.

Interplay of Neuroinflammation and Gut Microbiota Dysbiosis in Alzheimer's Disease Using Diffusion Kurtosis Imaging Biomarker in 3 × Tg-AD Mouse Models

The relationship between alterations in brain microstructure and dysbiosis of gut microbiota in Alzheimer's disease (AD) has garnered increasing attention, although the functional implications of these changes are not yet fully elucidated. This research examines how neuroinflammation, systemic inflammation, and gut microbiota interact in male 3 × Tg-AD and B6129SF1/J wild-type (WT) mice at 6 months-old (6-MO) and 12 months-old (12-MO). Employing a combination of behavioral assessments, diffusion kurtosis imaging (DKI), microbiota profiling, cytokine analysis, short-chain fatty acids (SCFAs), and immunohistochemistry, we explored the progression of AD-related pathology. Significant memory impairments in AD mice at both assessed ages were correlated with altered DKI parameters that suggest neuroinflammation and microstructural damage. We observed elevated levels of pro-inflammatory cytokines, such as IL-1β, IL-6, TNFα, and IFN-γ, in the serum, which were associated with increased activity of microglia and astrocytes in brain regions critical for memory. Although gut microbiota analysis did not reveal significant changes in alpha diversity, it did show notable differences in beta diversity and a diminished Firmicutes/Bacteroidetes (F/B) ratio in AD mice at 12-MO. Furthermore, a reduction in six kinds of SCFAs were identified at two time points of 6-MO and 12-MO, indicating widespread disruption in gut microbial metabolism. These findings underscore a complex bidirectional relationship between systemic inflammation and gut dysbiosis in AD, highlighting the gut-brain axis as a crucial factor in disease progression. This study emphasizes the potential of integrating DKI metrics, microbiota profiling, and SCFA analysis to enhance our understanding of AD pathology and to identify new therapeutic targets.

Role of Antioxidants in Modulating the Microbiota-Gut-Brain Axis and Their Impact on Neurodegenerative Diseases

This narrative review presents the role of antioxidants in regulating the gut microbiota and the impact on the gut-brain axis, with a particular focus on neurodegenerative diseases, such as Alzheimer's (AD) and Parkinson's disease (PD). These diseases are characterised by cognitive decline, motor dysfunction, and neuroinflammation, all of which are significantly exacerbated by oxidative stress. This review elucidates the contribution of oxidative damage to disease progression and explores the potential of antioxidants to mitigate these pathological processes through modulation of the gut microbiota and associated pathways. Based on recent studies retrieved from reputable databases, including PubMed, Web of Science, and Scopus, this article outlines the mechanisms by which antioxidants influence gut health and exert neuroprotective effects. Specifically, it discusses how antioxidants, including polyphenols, vitamins, and flavonoids, contribute to the reduction in reactive oxygen species (ROS) production and neuroinflammation, thereby promoting neuronal survival and minimising oxidative damage in the brain. In addition, the article explores the role of antioxidants in modulating key molecular pathways involved in oxidative stress and neuroinflammation, such as the NF-κB, Nrf2, MAPK, and PI3K/AKT pathways, which regulate ROS generation, inflammatory cytokine expression, and antioxidant responses essential for maintaining cellular homeostasis in both the gut and the central nervous system. In addition, this review explores the complex relationship between gut-derived metabolites, oxidative stress, and neurodegenerative diseases, highlighting how dysbiosis-an imbalance in the gut microbiota-can exacerbate oxidative stress and contribute to neuroinflammation, thereby accelerating the progression of such diseases as AD and PD. The review also examines the role of short-chain fatty acids (SCFAs) produced by beneficial gut bacteria in modulating these pathways to attenuate neuroinflammation and oxidative damage. Furthermore, the article explores the therapeutic potential of microbiota-targeted interventions, including antioxidant delivery by probiotics and prebiotics, as innovative strategies to restore microbial homeostasis and support brain health. By synthesising current knowledge on the interplay between antioxidants, the gut-brain axis, and the molecular mechanisms underlying neurodegeneration, this review highlights the therapeutic promise of antioxidant-based interventions in mitigating oxidative stress and neurodegenerative disease progression. It also highlights the need for further research into antioxidant-rich dietary strategies and microbiota-focused therapies as promising avenues for the prevention and treatment of neurodegenerative diseases.

Photobiomodulation and the oral-gut microbiome axis: therapeutic potential and challenges

This Perspective article explores the challenges associated with the direct application of photobiomodulation (PBM) to the gut and presents a novel hypothesis for indirect gut health modulation through oral microbiome alteration. Given the difficulties in delivering PBM effectively to deep gastrointestinal tissues, an alternative approach involves targeting the oral microbiome, which has a demonstrated relationship with the gut microbiome. Research indicates that PBM applied to the oral cavity could selectively alter microbial composition. This alteration may, via the oral-gut microbiome axis, indirectly impact gut health. This hypothesis, supported by preliminary studies, suggests that oral PBM could offer a promising non-invasive strategy for managing gut-related disorders. Furthermore, there may be a link between the oral microbiome and brain diseases. Given the proximity to the brain, PBM-induced changes in the oral microbiota could indirectly help prevent neurological disorders. However, further investigation is necessary to comprehensively elucidate the underlying mechanisms and therapeutic implications of this approach.

The Oral-Gut Microbiome-Brain Axis in Cognition

Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by cognitive decline and neuronal loss, affecting millions worldwide. Emerging evidence highlights the oral microbiome-a complex ecosystem of bacteria, fungi, viruses, and protozoa as a significant factor in cognitive health. Dysbiosis of the oral microbiome contributes to systemic inflammation, disrupts the blood-brain barrier, and promotes neuroinflammation, processes increasingly implicated in the pathogenesis of AD. This review examines the mechanisms linking oral microbiome dysbiosis to cognitive decline through the oral-brain and oral-gut-brain axis. These interconnected pathways enable bidirectional communication between the oral cavity, gut, and brain via neural, immune, and endocrine signaling. Oral pathogens, such as Porphyromonas gingivalis, along with virulence factors, including lipopolysaccharides (LPS) and gingipains, contribute to neuroinflammation, while metabolic byproducts, such as short-chain fatty acids (SCFAs) and peptidoglycans, further exacerbate systemic immune activation. Additionally, this review explores the influence of external factors, including diet, pH balance, medication use, smoking, alcohol consumption, and oral hygiene, on oral microbial diversity and stability, highlighting their role in shaping cognitive outcomes. The dynamic interplay between the oral and gut microbiomes reinforces the importance of microbial homeostasis in preserving systemic and neurological health. The interventions, including probiotics, prebiotics, and dietary modifications, offer promising strategies to support cognitive function and reduce the risk of neurodegenerative diseases, such as AD, by maintaining a diverse microbiome. Future longitudinal research is needed to identify the long-term impact of oral microbiome dysbiosis on cognition.

Lactobacillus Johnsonii YH1136 alleviates schizophrenia-like behavior in mice: a gut-microbiota-brain axis hypothesis study

Based on the microbiota-gut-brain axis (MGBA) hypothesis, probiotics play an increasingly important role in treating various psychiatric disorders. Schizophrenia (SCZ) is a common mental disease with a complex pathogenesis and is challenging to treat. Although studies have elucidated the mechanisms associated with the interactions between the microbiota-gut-brain axis and SCZ, few have specifically used probiotics as a therapeutic intervention for SCZ. Accordingly, the current study determines whether L. johnsonii YH1136 effectively prevents SCZ-like behavior in mice and identifies the associated key microbes and metabolites. An SCZ mouse model was established by intraperitoneal injection of MK-801; L. johnsonii YH1136 was administered via oral gavage. L. johnsonii YH1136 significantly improves abnormal behaviors, including psychomotor hyperactivity and sociability and alleviates aberrant enzyme expression associated with tryptophan metabolism in SCZ mice. Additionally, L. johnsonii YH1136 upregulates hippocampal brain-derived neurotrophic factor (BDNF) levels while downregulating tryptophan 2,3-dioxygenase (TDO2), indoleamine-pyrrole 2,3-dioxygenase 1 (IDO1), kynurenine aminotransferase 1 (KAT1). Subsequent 16S rRNA sequencing of intestinal contents suggests that L. johnsonii YH1136 modulates the gut flora structure and composition by increasing the relative abundance of Lactobacillus and decreasing Dubosiella in SCZ mice. N-acetylneuraminic acid and hypoxanthine are the key serum metabolites mediating the interaction between the MGBA and SCZ. These results partially reveal the mechanism underlying the effects of L. johnsonii YH1136 on SCZ-like behavior in mice, supporting the development of therapeutic L. johnsonii probiotic formulations against SCZ.

Synbiotic combination of 2'-fucosyllactose and Bifidobacterium mitigates neurodevelopmental disorders and ASD-like behaviors induced by valproic acid

Autism spectrum disorder (ASD) is a group of heterogeneous neurodevelopmental disorders characterized by social deficits and repetitive behaviors. Increasing evidence suggests that the gut microbiota influences neurodevelopment and behavior. In this study, we established an ASD model by administering valproic acid (VPA) to pregnant females, with male offspring receiving a daily synbiotic intervention for four weeks post-weaning. The results indicate that the synbiotic combination of 2'-Fucosyllactose (2'-FL) and Bifidobacterium animalis subsp. lactis BB-12 (BB-12) outperformed that of 2'-FL and Lactobacillus paracasei L9300BH (L9300BH) in alleviating social deficits, repetitive behaviors, neuronal damage, and dysregulated expression of social-related genes and neuroinflammatory markers in ASD mice. Additionally, the intervention with 2'-FL and BB-12 improved gut morphology and barrier integrity, reduced gut inflammation, and optimized the gut microbiota structure by increasing the abundance of Bifidobacteria and Akkermansia, known producers of short-chain fatty acids (SCFAs). Notably, levels of acetate, propionate, and butyrate were significantly elevated in fecal samples. In summary, the synbiotic combination of 2'-FL and BB-12 supports gut microbiota homeostasis, enhances fecal SCFA levels, and mitigates neurodevelopmental abnormalities in ASD mice.

High-throughput workflow for cultivation and characterization of gut microbiota strains with anti-inflammatory properties and metabolite signature associated with gut-brain communication

The gut microbiota is deeply interconnected with the brain, a phenomenon often referred to as the gut-brain axis. Dysfunction in the microbiota-gut-brain axis can cause various neurological and psychiatric disorders associated with chronic inflammation and gut microbiota dysbiosis. Therefore, cultivation of anaerobic human gut microbiota strains, and characterization of their safety status and immunomodulatory potential could contribute to deciphering the molecular mechanisms underlying the microbiota-gut-brain communication and revealed their biotherapeutic potential. However, poor cultivability of gut microbiota members, makes research into their physiological role challenging. Hence, we report a high-throughput workflow based on targeted cultivation linked to metagenome sequencing, combined with the bioinformatic search for gut members with anti-inflammatory properties which produce the most important microbial metabolites that affect brain function. With this approach, we isolated 147 bacterial strains, and 41 were characterized for their immunomodulatory status with 12 strains showing immunosuppressive features with ability of producing brain important metabolites. Through this workflow we established the best growing conditions essential for cultivation, archiving, phenotyping, and characterization of anaerobic gut bacteria important for microbiota-gut-brain-axis research, and characterized the safety and probiotic potential of 7 extremely oxygen-sensitive strains.

The microbiome's influence on obesity: mechanisms and therapeutic potential

In 2023, the World Obesity Atlas Federation concluded that more than 50% of the world's population would be overweight or obese within the next 12 years. At the heart of this epidemic lies the gut microbiota, a complex ecosystem that profoundly influences obesity-related metabolic health. Its multifaced role encompasses energy harvesting, inflammation, satiety signaling, gut barrier function, gut-brain communication, and adipose tissue homeostasis. Recognizing the complexities of the cross-talk between host physiology and gut microbiota is crucial for developing cutting-edge, microbiome-targeted therapies to address the global obesity crisis and its alarming health and economic repercussions. This narrative review analyzed the current state of knowledge, illuminating emerging research areas and their implications for leveraging gut microbial manipulations as therapeutic strategies to prevent and treat obesity and related disorders in humans. By elucidating the complex relationship between gut microflora and obesity, we aim to contribute to the growing body of knowledge underpinning this critical field, potentially paving the way for novel interventions to combat the worldwide obesity epidemic.

Protective Effects of Bifidobacterium Breve MCC1274 as a Novel Therapy for Alzheimer's Disease

Alzheimer's disease (AD) is the most common form of dementia and is characterized by memory impairment that significantly interferes with daily life. Therapeutic options for AD that substantively modify disease progression remain a critical unmet need. In this regard, the gut microbiota is crucial in maintaining human health by regulating metabolism and immune responses, and increasing evidence suggests that probiotics, particularly beneficial bacteria, can enhance memory and cognitive functions. Recent studies have highlighted the positive effects of Bifidobacterium breve MCC1274 (B. breve MCC1274) on individuals with mild cognitive impairment (MCI) and schizophrenia. Additionally, oral supplementation with B. breve MCC1274 has been shown to effectively prevent memory decline in AppNL-G-F mice. In relation to Alzheimer's pathology, oral supplementation with B. breve MCC1274 has been found to reduce amyloid-β (Aβ) accumulation and tau phosphorylation in both AppNL-G-F and wild-type (WT) mice. It also decreases microglial activation and increases levels of synaptic proteins. In this review, we examine the beneficial effects of B. breve MCC1274 on AD, exploring potential mechanisms of action and how this probiotic strain may aid in preventing or treating the disease. Furthermore, we discuss the broader implications of B. breve MCC1274 for improving overall host health and provide insights into future research directions for this promising probiotic therapy.

Sleep deprivation-induced shifts in gut microbiota: Implications for neurological disorders

Sleep deprivation is a prevalent issue in contemporary society, with significant ramifications for both physical and mental well-being. Emerging scientific evidence illuminates its intricate interplay with the gut-brain axis, a vital determinant of neurological function. Disruptions in sleep patterns disturb the delicate equilibrium of the gut microbiota, resulting in dysbiosis characterized by alterations in microbial composition and function. This dysbiosis contributes to the exacerbation of neurological disorders such as depression, anxiety, and cognitive decline through multifaceted mechanisms, including heightened neuroinflammation, disturbances in neurotransmitter signalling, and compromised integrity of the gut barrier. In response to these challenges, there is a burgeoning interest in therapeutic interventions aimed at restoring gut microbial balance and alleviating neurological symptoms precipitated by sleep deprivation. Probiotics, dietary modifications, and behavioural strategies represent promising avenues for modulating the gut microbiota and mitigating the adverse effects of sleep disturbances on neurological health. Moreover, the advent of personalized interventions guided by advanced omics technologies holds considerable potential for tailoring treatments to individualized needs and optimizing therapeutic outcomes. Interdisciplinary collaboration and concerted research efforts are imperative for elucidating the underlying mechanisms linking sleep, gut microbiota, and neurological function. Longitudinal studies, translational research endeavours, and advancements in technology are pivotal for unravelling the complex interplay between these intricate systems.

Targeting Cytokine-Mediated Inflammation in Brain Disorders: Developing New Treatment Strategies

Cytokine-mediated inflammation is increasingly recognized for playing a vital role in the pathophysiology of a wide range of brain disorders, including neurodegenerative, psychiatric, and neurodevelopmental problems. Pro-inflammatory cytokines such as interleukin-1 (IL-1), tumor necrosis factor-alpha (TNF-α), and interleukin-6 (IL-6) cause neuroinflammation, alter brain function, and accelerate disease development. Despite progress in understanding these pathways, effective medicines targeting brain inflammation are still limited. Traditional anti-inflammatory and immunomodulatory drugs are effective in peripheral inflammatory illnesses. Still, they face substantial hurdles when applied to the central nervous system (CNS), such as the blood-brain barrier (BBB) and unwanted systemic effects. This review highlights the developing treatment techniques for modifying cytokine-driven neuroinflammation, focusing on advances that selectively target critical cytokines involved in brain pathology. Novel approaches, including cytokine-specific inhibitors, antibody-based therapeutics, gene- and RNA-based interventions, and sophisticated drug delivery systems like nanoparticles, show promise with respect to lowering neuroinflammation with greater specificity and safety. Furthermore, developments in biomarker discoveries and neuroimaging techniques are improving our ability to monitor inflammatory responses, allowing for more accurate and personalized treatment regimens. Preclinical and clinical trial data demonstrate the therapeutic potential of these tailored techniques. However, significant challenges remain, such as improving delivery across the BBB and reducing off-target effects. As research advances, the creation of personalized, cytokine-centered therapeutics has the potential to alter the therapy landscape for brain illnesses, giving patients hope for better results and a higher quality of life.

Study on the Effect of Radish Sprouts on Short-Chain Fatty Acids and Gut Microbial Diversity in Healthy Individuals

This study aimed to assess the impact of radish sprouts on the gut microbiota of healthy individuals. Radish sprout additives, subjected to short-term storage and steam treatment, were used to intervene in an in vitro culture of human gut microbiota. The influence of radish sprouts on the gut microbiota was evaluated by monitoring short-chain fatty acid (SCFA) content and proportion in the fermentation broth, and microbial diversity was assessed using 16S rDNA amplicon sequencing. The results indicated that the gut microbiota produced a substantial amount of SCFA within 48 h of fermentation, with a right-skewed distribution across all groups. The addition of both digestates enhanced Firmicutes diversity, while Bacteroidetes and Proteobacteria diversity remained stable between the control and fresh sprout groups. The 30 s steam treatment group showed an increase in Bacteroidetes and a decrease in Proteobacteria diversity. The abundance of Bacilli, Bacillaceae, and Bacillus was significantly higher in both the fresh and steam-treated groups compared to the control. Both fresh and steam-treated radish sprout digestates enriched gut microbiota diversity, with steam treatment showing superior effects. These findings suggest that radish sprout consumption may positively influence gut microbiota, with steam treatment potentially enhancing these benefits.

Crosstalk between ROS-inflammatory gene expression axis in the progression of lung disorders

A significant number of deaths and disabilities worldwide are brought on by inflammatory lung diseases. Many inflammatory lung disorders, including chronic respiratory emphysema, resistant asthma, resistance to steroids, and coronavirus-infected lung infections, have severe variants for which there are no viable treatments; as a result, new treatment alternatives are needed. Here, we emphasize how oxidative imbalance contributes to the emergence of provocative lung problems that are challenging to treat. Endogenic antioxidant systems are not enough to avert free radical-mediated damage due to the induced overproduction of ROS. Pro-inflammatory mediators are then produced due to intracellular signaling events, which can harm the tissue and worsen the inflammatory response. Overproduction of ROS causes oxidative stress, which causes lung damage and various disease conditions. Invasive microorganisms or hazardous substances that are inhaled repeatedly can cause an excessive amount of ROS to be produced. By starting signal transduction pathways, increased ROS generation during inflammation may cause recurrent DNA damage and apoptosis and activate proto-oncogenes. This review provides information about new targets for conducting research in related domains or target factors to prevent, control, or treat such inflammatory oxidative stress-induced inflammatory lung disorders.

Advances in bio-polymer coatings for probiotic microencapsulation: chitosan and beyond for enhanced stability and controlled release

This review paper analyzes recent advancements in bio-polymer coatings for probiotic microencapsulation, with a particular emphasis on chitosan and its synergistic combinations with other materials. Probiotic microencapsulation is essential for protecting probiotics from environmental stresses, enhancing their stability, and ensuring effective delivery to the gut. The review begins with an overview of probiotic microencapsulation, highlighting its significance in safeguarding probiotics through processing, storage, and gastrointestinal transit. Advances in chitosan-based encapsulation are explored, including the integration of chitosan with other bio-polymers such as alginate, gelatin, and pectin, as well as the application of nanotechnology and innovative encapsulation techniques like spray drying and layer-by-layer assembly. Detailed mechanistic insights are integrated, illustrating how chitosan influences gut microbiota by promoting beneficial bacteria and suppressing pathogens, thus enhancing its role as a prebiotic or synbiotic. Furthermore, the review delves into chitosan's immunomodulatory effects, particularly in the context of inflammatory bowel disease (IBD) and autoimmune diseases, describing the immune signaling pathways influenced by chitosan and linking gut microbiota changes to improvements in systemic immunity. Recent clinical trials and human studies assessing the efficacy of chitosan-coated probiotics are presented, alongside a discussion of practical applications and a comparison of in vitro and in vivo findings to highlight real-world relevance. The sustainability of chitosan sources and their environmental impact are addressed, along with the novel concept of chitosan's role in the gut-brain axis. Finally, the review emphasizes future research needs, including the development of personalized probiotic therapies and the exploration of novel bio-polymers and encapsulation techniques.

Mechanisms and Emerging Regulators of Neuroinflammation: Exploring New Therapeutic Strategies for Neurological Disorders

Neuroinflammation is a complex and dynamic response of the central nervous system (CNS) to injury, infection, and disease. While acute neuroinflammation plays a protective role by facilitating pathogen clearance and tissue repair, chronic and dysregulated inflammation contributes significantly to the progression of neurodegenerative disorders such as Alzheimer's disease, Parkinson's disease, and Multiple Sclerosis. This review explores the cellular and molecular mechanisms underlying neuroinflammation, focusing on the roles of microglia, astrocytes, and peripheral immune cells. Key signaling pathways, including NF-κB, JAK-STAT, and the NLRP3 inflammasome, are discussed alongside emerging regulators such as non-coding RNAs, epigenetic modifications, and the gut-brain axis. The therapeutic landscape is evolving, with traditional anti-inflammatory drugs like NSAIDs and corticosteroids offering limited efficacy in chronic conditions. Immunomodulators, gene and RNA-based therapeutics, and stem cell methods have all shown promise for more specific and effective interventions. Additionally, the modulation of metabolic states and gut microbiota has emerged as a novel strategy to regulate neuroinflammation. Despite significant progress, challenges remain in translating these findings into clinically viable therapies. Future studies should concentrate on integrated, interdisciplinary methods to reduce chronic neuroinflammation and slowing the progression of neurodegenerative disorders, providing opportunities for revolutionary advances in CNS therapies.

Gut microbiome synthesizes important core metabolites to prevent cognitive decline and mitigate onset and progression of Alzheimer's disease

Background

This study explores how gut metabolites, produced through bacterial metabolism in the gut, influence neurological conditions like Alzheimer's disease (AD). Key metabolites such as succinate and short-chain fatty acids signal through the autonomic nervous system and can cross the blood-brain barrier, impacting central nervous system functions.

Objective

The aim is to examine the role of the gut microbiota in compensating for metabolic deficiencies in AD. By analyzing wild-type (WT) and APP/PS1 mice, the study investigates how the microbiome affects key metabolic processes and whether it can slow AD progression.

Methods

High-throughput sequencing data from the gut microbiomes of APP/PS1 transgenic AD model mice and age-matched WT C57BL/6 male mice were analyzed for microbial and metabolite profiles.

Results

Alpha and beta diversity analyses showed differences in microbial composition between groups. Partial least squares discriminant analysis and Anosim confirmed distinct microbiome profiles in WT and APP/PS1 mice. At the genus level, Vescimonas was more abundant in WT mice, while Odoribacter, Lacrimispora, Helicobacter, Bacteroides, and Alloprevotella were more prevalent in APP/PS1 mice.

Conclusions

While taxonomic differences did not directly link specific microorganisms to AD, functional analysis identified key metabolites-acetyl-CoA, glucose, succinate, lipids, choline, and acetylcholine-that may alleviate energy deficits and synaptic dysfunction. This study suggests that the microbiome may help compensate for AD-related impairments, opening avenues for microbiome-based therapies.

The Gut Microbiota's Role in Neurological, Psychiatric, and Neurodevelopmental Disorders

AIM

This article aims to explore the role of the human gut microbiota (GM) in the pathogenesis of neurological, psychiatric, and neurodevelopmental disorders, highlighting its influence on health and disease, and investigating potential therapeutic strategies targeting GM modulation.

MATERIALS AND METHODS

A comprehensive analysis of the gut microbiota's composition and its interaction with the human body, particularly, its role in neurological and psychiatric conditions, is provided. The review discusses factors influencing GM composition, including birth mode, breastfeeding, diet, medications, and geography. Additionally, it examines the GM's functions, such as nutrient absorption, immune regulation, and pathogen defense, alongside its interactions with the nervous system through the gut-brain axis, neurotransmitters, and short-chain fatty acids (SCFAs).

RESULTS

Alterations in the GM are linked to various disorders, including Parkinson's disease, multiple sclerosis, depression, schizophrenia, ADHD, and autism. The GM influences cognitive functions, stress responses, and mood regulation. Antibiotic use disrupts GM diversity, increasing the risk of metabolic disorders, obesity, and allergic diseases. Emerging therapies such as probiotics, prebiotics, and microbiota transplantation show promise in modulating the GM and alleviating symptoms of neurological and psychiatric conditions.

CONCLUSIONS

The modulation of the GM represents a promising approach for personalized treatment strategies. Further research is needed to better understand the underlying mechanisms and to develop targeted therapies aimed at restoring GM balance for improved clinical outcomes.

Alterations in Gut Microbiota Composition Are Associated with Changes in Emotional Distress in Children with Obstructive Sleep Apnea

Emerging evidence underscores the pivotal role of the gut microbiota in regulating emotional and behavioral responses via the microbiota-gut-brain axis. This study explores associations between pediatric obstructive sleep apnea (OSA), emotional distress (ED), and gut microbiome alterations before and after OSA treatment. Sixty-six children diagnosed with OSA via polysomnography participated, undergoing adenotonsillectomy alongside routine educational sessions. ED was assessed using the OSA-18 questionnaire, categorizing participants into high ED (scores ≥ 11, 52%) and low ED (scores < 11, 48%) groups. Gut microbiome analysis revealed significant diversity differences, with high ED linked to a reduced Shannon index (p = 0.03) and increased beta diversity (p = 0.01). Three months post-treatment, significant improvements were observed in OSA symptoms, ED scores, and gut microbiome alpha diversity metrics among 55 participants (all p < 0.04). Moreover, changes in the relative abundances of Veillonella, Bifidobacterium, Flavonifractor, and Agathobacter, as well as ultra-low frequency power and low frequency power of sleep heart rate variability, were independently associated with ED score alterations. These findings underscore the gut microbiome's critical role in the emotional and behavioral symptoms associated with pediatric OSA, suggesting that microbiome-targeted interventions could complement traditional treatments for ED reduction and emphasizing the need for further research.

D, Rajendran P, N H, Singh S A. Exploring the potential of probiotics in Alzheimer's disease and gut dysbiosis

Alzheimer's disease is a fatal neurodegenerative disorder that causes memory loss and cognitive decline in older people. There is increasing evidence suggesting that gut microbiota alteration is a cause of Alzheimer's disease pathogenesis. This review explores the link between gut dysbiosis and the development of Alzheimer's disease contributing to neuroinflammation, amyloid β accumulation, and cognitive decline. We examine the recent studies that illustrate the gut-brain axis (GBA) as a bidirectional communication between the gut and brain and how its alteration can influence neurological health. Furthermore, we discuss the potential of probiotic supplementation as a management approach to restore gut microbiota balance, and ultimately improve cognitive function in AD patients. Based on current research findings, this review aims to provide insights into the promising role of probiotics in Alzheimer's disease management and the need for further investigation into microbiota-targeted interventions.

Gut microbiota in very early systemic sclerosis: the first case-control taxonomic and functional characterisation highlighting an altered butyric acid profile

OBJECTIVES

In systemic sclerosis (SSc), gastrointestinal involvement is one of the earliest events. We compared the gut microbiota (GM), its short-chain fatty acids (SCFAs) and host-derived free fatty acids (FFAs) in patients with very early diagnosis of SSc (VEDOSS) and definite SSc.

METHODS

Stool samples of 26 patients with SSc, 18 patients with VEDOSS and 20 healthy controls (HC) were collected. The GM was assessed through 16S rRNA sequencing, while SCFAs and FFAs were assessed by gas chromatography-mass spectrometry.

RESULTS

In patients with VEDOSS, an increase in Bacteroidales and Oscillospirales orders and a decrease in Bacilli class, Blautia, Romboutsia, Streptococcus and Turicibacter genera was detected in comparison with HC. In patients with SSc, an elevated number of Acidaminococcaceae and Sutterellaceae families, along with a decrease of the Peptostreptococcaceae family and Anaerostipes, Blautia, Romboutsia and Turicibacter genera was found in comparison with HC. Patients with SSc and VEDOSS had a significantly lower butyrate and higher acetate with respect to HC. In VEDOSS, an increase in Oscillospiraceae family and Anaerostipes genus, and a decrease in Alphaproteobacteria class, and Lactobacillales order was identified with respect to SSc. Moreover, patients with VEDOSS exhibited higher acetate and lower valerate compared with definite SSc.

CONCLUSION

A GM dysbiosis with depletion of beneficial anti-inflammatory bacteria (especially butyrate-producing) and a significant decrease in faecal butyrate was identified in patients with VEDOSS. This early GM imbalance may foster the growth of inflammatory microbes, worsening intestinal dysbiosis and inflammation in early SSc stages. The potential butyrate administration in early disease phases might be considered as a novel therapeutic approach to mitigate gastrointestinal discomfort and progression preserving patient's quality of life.

The Impact of Probiotics on Clinical Symptoms and Peripheral Cytokines Levels in Parkinson's Disease: Preliminary In Vivo Data

Introduction. Previous studies have shown that probiotics have positive effects on both motor and non-motor symptoms in Parkinson's disease (PD). Additionally, in preclinical settings, probiotics have demonstrated the ability to counteract neuronal loss and alpha-synuclein aggregation, important pathological hallmarks of PD. Notably, preliminary in vitro studies have revealed the immunomodulatory properties of probiotics. This study aims to evaluate the impact of probiotics on symptoms and peripheral cytokines levels in PD patients compared to placebo. Methods. Patients were enrolled and blindly randomized to receive either active probiotics (comprising Bifidobacterium animalis subsp. lactis BS01 LMG P-21384, Bifidobacterium longum BL03 DSM 16603, Bifidobacterium adolescentis BA02 DSM 18351, Fructo-oligosaccharides and Maltodextrin-Group A) or placebo (Maltodextrin-Group B). Clinical evaluations and plasma levels cytokines (TNF-α, IFN-γ, IL-6, and TGF-β) were also assessed at enrollment and after 12 weeks. Anti-parkinsonian therapy remained stable throughout the study. Results. Forty PD patients were recruited. After 12 weeks, Group A showed significant improvement in motor symptoms (UPDRS III: 13.89 ± 4.08 vs. 12.74 ± 4.57, p = 0.028) and non-motor symptoms (NMSS: 34.32 ± 21.41 vs. 30.11 ± 19.89, p = 0.041), with notable improvement in the gastrointestinal sub-item (3.79 ± 4.14 vs. 1.89 ± 2.54, p = 0.021). A reduction of IFN-γ levels was observed in both groups, but group A also showed a significant decrease in IL-6 and a slight increase in the anti-inflammatory cytokine TGF-β. Conclusions. Our data suggest that probiotics may modulate peripheral cytokines levels and improve clinical symptoms in PD patients. Probiotics may, therefore, represent a valuable adjunctive therapy to conventional anti-parkinsonian drugs.

Underneath the Gut-Brain Axis in IBD-Evidence of the Non-Obvious

The gut-brain axis (GBA) plays a pivotal role in human health and wellness by orchestrating complex bidirectional regulation and influencing numerous critical processes within the body. Over the past decade, research has increasingly focused on the GBA in the context of inflammatory bowel disease (IBD). Beyond its well-documented effects on the GBA-enteric nervous system and vagus nerve dysregulation, and gut microbiota misbalance-IBD also leads to impairments in the metabolic and cellular functions: metabolic dysregulation, mitochondrial dysfunction, cationic transport, and cytoskeleton dysregulation. These systemic effects are currently underexplored in relation to the GBA; however, they are crucial for the nervous system cells' functioning. This review summarizes the studies on the particular mechanisms of metabolic dysregulation, mitochondrial dysfunction, cationic transport, and cytoskeleton impairments in IBD. Understanding the involvement of these processes in the GBA may help find new therapeutic targets and develop systemic approaches to improve the quality of life in IBD patients.

Bibliometric analysis of research hotspots and trends on the relationship between the gut microbiota and depression from 2020 to 2024

INTRODUCTION

In recent years, an increasing body of research has illustrated a strong correlation between gut microbiota and depression. However, there has yet to be a comprehensive discussion or summary of the latest advancements and trends in this field.

METHODS

We retrieved research articles focused on gut microbiota and depression through the WOS database from 2020 to 2024, using visual text analysis tools such as CiteSpace and VOSviewer.

RESULTS

The literature on the relationship between gut microbiota and depression surged from 396 papers in 2020 to 711 by 2024. During this period, the journal with the highest publication rate was Nutrients. China led the countries in contributions, while University College Cork topped the institutions. Kenji Hashimoto emerged as the most prolific author. The most cited paper was authored by Cryan JF et al., published in 2019 in Physiol Rev. The keywords "gut microbiota," "depression," and "anxiety" appeared most frequently, while recent years saw explosive increases in terms such as "growth performance," "receptors," "depression-like phenotypes," "stress response," "gastrointestinal symptoms," "reliability," and "neurogenesis."

DISCUSSION

Our article displayed the overview of the relationship between the gut microbiome and depression from 2020 to 2024 using bibliometric methods, providing perspectives and research hotspots for studies exploring the correlation between the gut microbiome and depression.

Polysaccharide-based chondroitin sulfate macromolecule loaded hydrogel/scaffolds in wound healing- A comprehensive review on possibilities, research gaps, and safety assessment

Wound healing is an intricate multifactorial process that may alter the extent of scarring left by the wound. A substantial portion of the global population is impacted by non-healing wounds, imposing significant financial burdens on the healthcare system. The conventional dosage forms fail to improve the condition, especially in the presence of other morbidities. Thus, there is a pressing requirement for a type of wound dressing that can safeguard the wound site and facilitate skin regeneration, ultimately expediting the healing process. In this context, Chondroitin sulfate (CS), a sulfated glycosaminoglycan material, is capable of hydrating tissues and further promoting the healing. Thus, this comprehensive review article delves into the recent advancement of CS-based hydrogel/scaffolds for wound healing management. The article initially summarizes the various physicochemical characteristics and sources of CS, followed by a brief understanding of the importance of hydrogel and CS in tissue regeneration processes. This is the first instance of such a comprehensive summarization of CS-based hydrogel/scaffolds in wound healing, focusing more on the mechanistic wound healing process, furnishing the recent innovations and toxicity profile. This contemporary review provides a profound acquaintance of strategies for contemporary challenges and future direction in CS-based hydrogel/scaffolds for wound healing.

Advances in understanding biomarkers and treating neurological diseases - Role of the cerebellar dysfunction and emerging therapies

Cerebellar dysfunction is increasingly recognized as a critical factor in various neurological diseases, including Alzheimer's disease (AD), Parkinson's disease (PD), and amyotrophic lateral sclerosis (ALS). Research has revealed distinct cerebellar atrophy patterns in conditions such as AD and multiple system atrophy, and studies in mice have highlighted its impact on motor control and cognitive functions. Emerging research into autism spectrum disorder (ASD) has identified key targets, such as elevated levels of chemokine receptors and ZIC family genes. Biomarkers, including cerebrospinal fluid (CSF), genetic markers, and advances in AI and bioinformatics, are enhancing early diagnosis and personalized treatment across neurodegenerative disorders. Notable advancements include improved diagnostic tools, gene therapy, and novel clinical trials. Despite progress, challenges such as the bloodbrain barrier and neuroinflammation persist. Current therapies for AD, PD, HD, and ALS, including antisense oligonucleotides and stem cell treatments, show promise but require further investigation. A comprehensive approach that integrates diagnostic methods and innovative therapies is essential for effective management and improved patient outcomes.

Cancer Therapy-Induced Encephalitis

Encephalitis associated with cancer therapies is a rare but serious complication that can significantly impact patients' quality of life and it requires prompt identification and management. Over the past two decades, immunotherapy-particularly immune checkpoint inhibitors-has become a cornerstone of cancer treatment, with up to half of metastatic cancer patients in economically developed countries now receiving these therapies. The widespread adoption of immunotherapy has led to improved survival rates and long-term remissions, even in patients with advanced metastatic disease. However, as immune modulators, these therapies can trigger a range of immune-related adverse events, including a variety of novel neurological toxicities. Among these, encephalitis is of particular concern due to its potential severity, which can compromise treatment outcomes. This review aims to provide a comprehensive overview of the literature on this condition, highlighting optimal diagnostic strategies and management approaches to mitigate the risk of significant morbidity, while also comparing encephalitis induced by immunotherapy with that caused by traditional chemotherapies and targeted oncologic treatments.

Novelties on Neuroinflammation in Alzheimer's Disease-Focus on Gut and Oral Microbiota Involvement

Recent studies underscore the role of gut and oral microbiota in influencing neuroinflammation through the microbiota-gut-brain axis, including in Alzheimer's disease (AD). This review aims to provide a comprehensive synthesis of recent findings on the involvement of gut and oral microbiota in the neuroinflammatory processes associated with AD, emphasizing novel insights and therapeutic implications. This review reveals that dysbiosis in AD patients' gut and oral microbiota is linked to heightened peripheral and central inflammatory responses. Specific bacterial taxa, such as Bacteroides and Firmicutes in the gut, as well as Porphyromonas gingivalis in the oral cavity, are notably altered in AD, leading to significant changes in microglial activation and cytokine production. Gut microbiota alterations are associated with increased intestinal permeability, facilitating the translocation of endotoxins like lipopolysaccharides (LPS) into the bloodstream and exacerbating neuroinflammation by activating the brain's toll-like receptor 4 (TLR4) pathways. Furthermore, microbiota-derived metabolites, including short-chain fatty acids (SCFAs) and amyloid peptides, can cross the blood-brain barrier and modulate neuroinflammatory responses. While microbial amyloids may contribute to amyloid-beta aggregation in the brain, certain SCFAs like butyrate exhibit anti-inflammatory properties, suggesting a potential therapeutic avenue to mitigate neuroinflammation. This review not only highlights the critical role of microbiota in AD pathology but also offers a ray of hope by suggesting that modulating gut and oral microbiota could represent a novel therapeutic strategy for reducing neuroinflammation and slowing disease progression.

Unlocking the possibilities of therapeutic potential of silymarin and silibinin against neurodegenerative Diseases-A mechanistic overview

Silymarin, a bioflavonoid derived from the Silybum marianum plant, was discovered in 1960. It contains C25 and has been extensively used as a therapeutic agent against liver-related diseases caused by alcohol addiction, acute viral hepatitis, and toxins-inducing liver failure. Its efficacy stems from its role as a potent anti-oxidant and scavenger of free radicals, employed through various mechanisms. Additionally, silymarin or silybin possesses immunomodulatory characteristics, impacting immune-enhancing and immune-suppressive functions. Recently, silymarin has been recognized as a potential neuroprotective therapy for various neurological conditions, including Parkinson's and Alzheimer's diseases, along with conditions related to cerebral ischemia. Its hepatoprotective qualities, primarily due to its anti-oxidant and tissue-regenerating properties, are well-established. Silymarin also enhances health by modifying processes such as inflammation, β-amyloid accumulation, cellular estrogenic receptor mediation, and apoptotic machinery. While believed to reduce oxidative stress and support neuroprotective mechanisms, these effects represent just one aspect of the compound's multifaceted protective action. This review article further delves into the possibilities of potential therapeutic advancement of silymarin and silibinin for the management of neurodegenerative disorders via mechanics modules.

Redox Homeostasis, Gut Microbiota, and Epigenetics in Neurodegenerative Diseases: A Systematic Review

Neurodegenerative diseases encompass a spectrum of disorders marked by the progressive degeneration of the structure and function of the nervous system. These conditions, including Parkinson's disease (PD), Alzheimer's disease (AD), Huntington's disease (HD), Amyotrophic lateral sclerosis (ALS), and Multiple sclerosis (MS), often lead to severe cognitive and motor deficits. A critical component of neurodegenerative disease pathologies is the imbalance between pro-oxidant and antioxidant mechanisms, culminating in oxidative stress. The brain's high oxygen consumption and lipid-rich environment make it particularly vulnerable to oxidative damage. Pro-oxidants such as reactive nitrogen species (RNS) and reactive oxygen species (ROS) are continuously generated during normal metabolism, counteracted by enzymatic and non-enzymatic antioxidant defenses. In neurodegenerative diseases, this balance is disrupted, leading to neuronal damage. This systematic review explores the roles of oxidative stress, gut microbiota, and epigenetic modifications in neurodegenerative diseases, aiming to elucidate the interplay between these factors and identify potential therapeutic strategies. We conducted a comprehensive search of articles published in 2024 across major databases, focusing on studies examining the relationships between redox homeostasis, gut microbiota, and epigenetic changes in neurodegeneration. A total of 161 studies were included, comprising clinical trials, observational studies, and experimental research. Our findings reveal that oxidative stress plays a central role in the pathogenesis of neurodegenerative diseases, with gut microbiota composition and epigenetic modifications significantly influencing redox balance. Specific bacterial taxa and epigenetic markers were identified as potential modulators of oxidative stress, suggesting novel avenues for therapeutic intervention. Moreover, recent evidence from human and animal studies supports the emerging concept of targeting redox homeostasis through microbiota and epigenetic therapies. Future research should focus on validating these targets in clinical settings and exploring the potential for personalized medicine strategies based on individual microbiota and epigenetic profiles.