The Gut-Brain Axis

Treatments for weight gain in schizophrenia

PURPOSE OF REVIEW

Obesity and related metabolic disorders are extremely common in psychiatric patients, particularly in those with schizophrenia. Elucidating this link's neurobiology may inform clinicians and researchers of rational therapeutic approaches necessary to optimize clinical outcomes.

RECENT FINDINGS

Current literature highlights the pivotal role of the inflammation-oxidative stress-insulin resistance loop in the pathophysiology of both metabolic and neuropsychiatric disorders. The concept of 'diabetophrenia' is put forward to highlight the overlapping neurobiological mechanisms underlying metabolic dysfunction and schizophrenia symptoms. Innovative treatments, including the combination of xanomeline with trospium and incretin-based medicines, demonstrate encouraging potential in addressing such complex health challenges.

SUMMARY

The nuanced dynamics of chronic inflammation and psychiatric symptomatology underscore the significance of addressing both metabolic and mental health factors in a cohesive fashion while considering unique psychosocial contexts, dietary preferences, and lifestyle choices. A multidisciplinary strategy is essential for incorporating counseling, dietary interventions, behavioral therapies, and pharmacotherapy into the management of schizophrenia. The ensuing enhanced collaboration among healthcare professionals may render obsolete the prevailing siloed conceptualizations of mental disorders, opening new vistas for generating synergistic insights into the mind-body systems and leading to improved health and quality of life for patients with schizophrenia and other psychiatric conditions.

Advances in dietary polyphenols: Regulation of inflammatory bowel disease (IBD) via bile acid metabolism and the gut-brain axis

Dietary polyphenols represent a diverse group of plant-derived compounds known for their extensive biological activities, offering significant promise in the prevention and treatment of various chronic illnesses. Despite their potential, advancements in their research have been curtailed by challenges in structural analysis and limitations in existing research models. This review marks a pioneering exploration into how bile acids, gut microbiota, and the gut-brain axis serve as conduits through which dietary polyphenols can exert therapeutic effects on Inflammatory Bowel Disease (IBD). This review enriches understanding of their biological functions and addresses common obstacles in the study of natural polyphenols. It provides a comprehensive examination of the role of dietary polyphenols in modulating bile acid metabolism and mitigating IBD, covering aspects such as polyphenols, bile acid metabolism, oxidative stress, inflammation, and the nervous system. This work opens new vistas in appreciating the full spectrum of polyphenol benefits, laying the groundwork for future explorations in this domain.

Altered functional connectivity within and between resting-state networks in ulcerative colitis

Patients with ulcerative colitis (UC) often exhibit affective disorders, such as depression and anxiety. The underlying neurological mechanisms of these symptoms, however, remain poorly understood. This study aimed to explore alterations in functional connectivity (FC) both within and between resting-state networks (RSNs) in individuals with ulcerative colitis. Twelve meaningful RSNs were identified from 22 ulcerative colitis patients and 23 healthy controls using independent component analysis of functional magnetic resonance imaging data. Correlation analyses were performed between clinical indices, neuropsychological assessments and neuroimaging data. Compared with healthy controls, UC patients showed increased intranetwork FC, mainly located in the right temporal pole, orbitofrontal cortex, and left superior temporal and Rolandic opercular cortices within the auditory network. Increased intranetwork FC in the Rolandic opercular cortex was also observed in UC patients during remission phase, while no significant alterations were detected in patients with active-phase UC. In addition, UC patients exhibited increased connectivity between the dorsal attention and the left frontoparietal network, as well as between the anterior default mode network and the posterior default mode network, with distinct patterns of internetwork connectivity observed across different clinical phases. No significant correlations were found between altered brain regions and psychological scales in UC patients. These findings imply that UC patients may undergo functional network alterations, affecting both intranetwork connectivity within RSNs and internetwork connectivity between RSNs.

Restorative Effects of Short-Chain Fatty Acids on Corneal Homeostasis Disrupted by Antibiotic-Induced Gut Dysbiosis

The gut microbiota plays a crucial regulatory role in various physiological processes, yet its impact on corneal homeostasis remains insufficiently understood. Here, the effects of antibiotic-induced gut dysbiosis (AIGD) and germ-free conditions were investigated on circadian gene expression, barrier integrity, nerve density, and immune cell activity in the corneas of mice. Both AIGD and germ-free conditions significantly disrupted the overall transcriptomic profile and circadian transcriptomic oscillations in the cornea, as indicated by RNA sequencing. These molecular disturbances were accompanied by a reduction in corneal epithelial thickness, nerve density, corneal sensitivity, and compromised barrier function. Notably, supplementation with short-chain fatty acids (SCFAs) significantly restored corneal integrity in AIGD mice. Further single-cell sequencing revealed that SCFA receptors G-protein-coupled receptor 109A (Hcar2), olfactory receptor 78 (Olfr78), and G-protein-coupled receptor 43 (Ffar2) are expressed in corneal epithelial basal cells, embryonically derived macrophages, perivascular cells, and γδ T cells, respectively. In conclusion, this study demonstrated that the gut microbiota plays a critical role in corneal physiology by regulating circadian gene expression and maintaining barrier function. These findings enhance our understanding of the gut-eye axis, highlighting the cornea as a target for microbiota-derived metabolic signals and underlining the potential therapeutic value of SCFAs in treating corneal dysfunction.

Landscapes of gut microbiome and blood metabolomic signatures in relapsing remitting multiple sclerosis

Although disturbances in the gut microbiome have been implicated in multiple sclerosis (MS), little is known about the changes and interactions between the gut microbiome and blood metabolome, and how these changes affect disease-modifying therapy (DMT) in preventing the progression of MS. In this study, the structure and composition of the gut microbiota were evaluated using 16S rRNA gene sequencing and an untargeted metabolomics approach was used to compare the serum metabolite profiles from patients with relapsing-remitting MS (RRMS) and healthy controls (HCs). Results indicated that RRMS was characterized by phase-dependent α-phylogenetic diversity and significant disturbances in serum glycerophospholipid metabolism. Notably, α-phylogenetic diversity was significantly decreased in RRMS patients during the chronic phase (CMS) compared with those in the acute phase (AMS). A distinctive combination of two elevated genera (Slackia, Lactobacillus) and five glycerophospholipid metabolism-associated metabolites (four increased: GPCho(22:5/20:3), PC(18:2(9Z,12Z)/16:0), PE(16:0/18:2(9Z,12Z)), PE(18:1(11Z)/18:2(9Z,12Z)); one decreased: PS(15:0/22:1(13Z))) in RRMS patients when comparing to HCs. Moreover, a biomarker panel consisting of four microbial genera (three decreased: Lysinibacillus, Parabacteroides, UBA1819; one increased: Lachnoanaerobaculum) and two glycerophospholipid metabolism-associated metabolites (one increased: PE(P-16:0/22:6); one decreased: CL(i-12:0/i-16:0/i-17:0/i-12:0)) effectively discriminated CMS patients from AMS patients, which indicate correlation with higher disability. Additionally, DMTs appeared to attenuate MS progression by reducing UBA1819 and upregulating CL(i-12:0/i-16:0/i-17:0/i-12:0). These findings expand our understanding of the microbiome and metabolome roles in RRMS and may contribute to identifying novel diagnostic biomarkers and promising therapeutic targets.

Decreased gut microbiome-derived indole-3-propionic acid mediates the exacerbation of myocardial ischemia/reperfusion injury following depression via the brain-gut-heart axis

Despite the increasing recognition of the interplay between depression and cardiovascular disease (CVD), the precise mechanisms by which depression contributes to the pathogenesis of cardiovascular disease remain inadequately understood. The involvement of gut microbiota and their metabolites to health and disease susceptibility has been gaining increasing attention. In this study, it was found that depression exacerbated cardiac injury, impaired cardiac function (EF%: P < 0.01; FS%: P < 0.05), hindered long-term survival (P < 0.01), and intensified adverse cardiac remodeling (WGA: P < 0.01; MASSON: P < 0.0001) after myocardial ischemia/reperfusion (MI/R) in mice. Then we found that mice receiving microbiota transplants from chronic social defeat stress (CSDS) mice exhibited worse cardiac function (EF%: P < 0.01; FS%: P < 0.01) than those receiving microbiota transplants from non-CSDS mice after MI/R injury. Moreover, impaired tryptophan metabolism due to alterations in gut microbiota composition and structure was observed in the CSDS mice. Mechanistically, we analyzed the metabolomics of fecal and serum samples from CSDS mice and identified indole-3-propionic acid (IPA) as a protective agent for cardiomyocytes against ferroptosis after MI/R via NRF2/System xc-/GPX4 axis, played a role in mediating the detrimental influence of depression on MI/R. Our findings provide new insights into the role of the gut microbiota and IPA in depression and CVD, forming the basis of intervention strategies aimed at mitigating the deterioration of cardiac function following MI/R in patients experiencing depression.

Hyperforin-induced gut microbiota metabolite carbocysteine protects against depressive-like behaviors in mice by modulating the colonic mucus barrier

OBJECTIVE

Depression affects millions, and current treatments have limitations, necessitating new approaches. Earlier research confirms Hyperforin's ability to reduce anhedonic behaviors in mice and modulate gut microbiota. This study aims to identify specific metabolic changes induced by Hyperforin that could illuminate its impact on gut microbiome metabolism, possibly uncovering novel metabolites for developing antidepressant therapies.

METHODS

Following the chronic stress model, untargeted metabolomic analysis of fecal samples was conducted to identify metabolic changes induced by Hyperforin. Bioinformatics tools analyzed the origins of differentially expressed metabolites and their correlation with Akkermansia muciniphila and Muribaculum intestinale. The significant metabolite Carbocysteine was further investigated for its antidepressant effects using behavioral assays in a mouse model of depression. Additionally, the response of the colonic mucus barrier was evaluated using Periodic Acid-Schiff (PAS) staining, scanning electron microscopy (SEM), and enzyme-linked immunosorbent assays (ELISA).

RESULTS

Hyperforin significantly altered fecal metabolite profiles in stressed mice, with a notable shift in 239 metabolites mainly associated with co-metabolism pathways and microbiota-specific processes. Among these, Carbocysteine emerged as a key metabolite linked to beneficial bacteria Akkermansia muciniphila and Muribaculum intestinale, with its levels significantly elevated following Hyperforin treatment. Behavioral assessments indicated that Carbocysteine supplementation ameliorated depressive-like behaviors in the chronic restraint stress mouse model. It also enhanced colonic mucus production and integrity.

CONCLUSION

Our research highlights Hyperforin's role in modulating gut microbiota metabolism and identifies Carbocysteine as a potential antidepressant. These findings advance our understanding of the gut-brain axis (GBA) in depression and pave the way for developing new therapeutics.

Five-month real-ambient PM2.5 exposure impairs learning in Brown Norway rats: Insights from multi omics-based analysis

PM2.5, recognized as a potential pathogenic factor for nervous system diseases, remains an area with many unknowns, particularly regarding its effects on human health. After five-month real-ambient PM2.5 exposure, we observed no significant pathological damage to the lung, liver, spleen, or kidney tissues. However, PM2.5 exposure led to neuronal degeneration in the hippocampal CA1 region of Brown Norway (BN) rats. The level of IL-6, IL-13, IL-1β, IL-12, IL-4, GRO/KC, MIP-1α, CM-CSF significantly increased in lung lavage fluid (P < 0.05 for all). Notably, we detected a slight impairment in spatial learning ability, as evidenced by the Barnes maze training outcomes. There were no significant changes in the bacterial community in lung lavage fluid (P = 0.621), but the bacterial community in the gut significantly changed (P < 0.001), with more species identified (P < 0.05). The metabolomic analysis revealed 147 and 149 significantly changed metabolites in the pulmonary system and serum, respectively (P < 0.05). PM2.5 exposure caused a decrease in Nervonic acid (NA) in both the lung and serum, which likely contributed to spatial learning impairment (P < 0.01). The correlation between lung metabolites, gut bacterial species, and serum metabolites indicated that PM2.5 exposure likely impaired spatial learning through the lung-gut-brain axis pathway. Lung and serum metabolic disorders and intestinal microbial imbalance occurred in BN rats post-five-month real-ambient PM2.5 exposure. There were two potential ways that PM2.5 exposure caused the decline of spatial learning ability in wild-type BN rats: (1) PM2.5 exposure led to a significant decrease of neuroprotective Nervonic acid in lung and serum metabolites. (2) PM2.5 exposure likely led to reduced spatial learning ability through the lung-gut-brain axis.

Study on the comorbid mechanisms of sarcopenia and late-life depression

The increasing global aging population has brought greater focus to age-related diseases, particularly muscle-brain comorbidities such as sarcopenia and late-life depression. Sarcopenia, defined by the gradual loss of muscle mass and function, is notably prevalent among older individuals, while late-life depression profoundly affects their mental health and overall well-being. Epidemiological evidence suggests a high co-occurrence of these two conditions, although the precise biological mechanisms linking them remain inadequately understood. This review synthesizes the existing body of literature on sarcopenia and late-life depression, examining their definitions, prevalence, clinical presentations, and available treatments. The goal is to clarify the potential connections between these comorbidities and offer a theoretical framework for the development of future preventive and therapeutic strategies.

Lung-specific SFTPC mutations lead to neurodevelopmental disorders with neuroinflammation

Neurodevelopmental disorders (NDDs) are characterized by diverse genetic underpinnings and abnormalities in the structure and function of the central nervous system. While the lung-specific SFTPC gene is critical for pulmonary development and homeostasis, its potential involvement in NDDs has not been previously explored. In this study, we identified compound heterozygous variants of SFTPC in two children diagnosed with NDDs, inherited from carrier parents. Bioinformatic analyses predicted these variants to be deleterious, and patient blood samples confirmed reduced SFTPC protein levels. To investigate the functional impact of these mutations, we generated a Sftpc-knock-in (Sftpc-KI) mouse model carrying the defective alleles. The Sftpc-KI mice exhibited significantly reduced Sftpc expression in both lung and blood samples. Remarkably, despite its lung-specific expression, Sftpc-KI mice displayed pronounced impairments in neurobehavioral performance. Proteomic analyses of the Sftpc-KI mouse brain revealed dysregulated proteins associated with neuroinflammation. Furthermore, primary microglial cells isolated from these mice exhibited heightened expression of M1 activation markers, indicating aberrant microglial activation. Our findings uncover a previously unrecognized connection between lung-specific SFTPC dysfunction and neurodevelopmental disorders, suggesting the existence of a novel brain-lung axis and opening new avenues for research into the molecular mechanisms underlying NDDs.

Ingestible Smart Capsules for Chemical Sensing in the Gut

The development of novel ingestible sensors can aid physicians and patients in obtaining precise data on the health status of the gut at a local level. This in turn can facilitate earlier and more accurate disease diagnosis, improve the delivery of point-of-care medicine, and allow monitoring of the gastrointestinal (GI) tract status. This Tutorial overviews characteristics of the gut for inexpert readers and reviews emerging chemical sensing technologies for the GI tract from an analytical chemistry viewpoint.

Autism Spectrum Disorder, Oral Implications, and Oral Microbiota

Background/Objectives: Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder characterized by difficulties in social interaction, communication, and repetitive behaviors. Recent evidence indicates a significant relationship between ASD and imbalances in microbiota, particularly in the oral and gastrointestinal areas. This review examines the impact of oral microbiota, self-injurious behaviors (SIB), sensory sensitivity, and dietary choices on the comorbidities associated with ASD. Methods: An extensive literature review was conducted using PubMed and Scopus. The focus was on human studies with full-text availability, utilizing search terms related to ASD, oral health, oral microbiota, and neurodevelopmental disorders. The research was evaluated for methodological quality and its relevance to the connections between microbiota, oral health, and ASD. Results: Individuals with ASD face unique oral health challenges, including injuries from self-injurious behaviors and increased sensory sensitivity, which complicate oral hygiene and care. Selective eating can lead to nutritional deficiencies and worsen oral health issues. Dysbiosis in oral and gut microbiota, marked by altered levels of acetate, propionate, and butyrate, interferes with gut-brain and oral-brain connections, contributing to behavioral and neurological symptoms. Treatment options such as probiotics, fecal microbiota transfer, and sensory integration therapies can potentially alleviate symptoms and improve quality of life. Conclusions: The relationship between ASD, oral health, and microbiota suggests a bidirectional influence through neuroinflammatory mechanisms and metabolic disturbances. Proactive strategies focusing on microbiota and dental health may help reduce comorbidities and enhance the overall management of ASD, underscoring the need for further research into microbiota-host interactions and their therapeutic potential.

Association between cognitive functioning and microbiota-gut-brain axis mediators in a memory clinic population

Introduction

A growing body of evidence recognises the role of signaling molecule of the microbiota-gut-brain axis (MGBA) in cognitive impairment (CI), but data on the link with alterations in specific cognitive domains are limited. We compared the functioning in several cognitive domains (i.e., memory, visuo-constructional, executive, and language) among cognitively unimpaired (CU) subjects, patients with CI due to Alzheimer’s disease (CI-AD) and not due to AD (CI-NAD). Then, we investigated the association of these cognitive domains with the gut microbiota (GM), MGBA mediators, and neurodegeneration-related markers.

Materials and methods

The study included 34 CI-AD, 38 CI-NAD, and 13 CU. Memory, visuo-constructional, executive, and language domains were assessed using composite measures. Faecal GM composition was inferred using 16S rRNA gene sequencing. MGBA mediators included the blood quantification of bacterial products (lipolysaccharide, LPS), cell adhesion molecules indicative of endothelial damage, vascular changes or overexpressed in response to infections, and pro- and anti-inflammatory cytokines. Neurodegeneration-related markers included plasma phosphorylated tau (p-tau181), neurofilament light chain (NfL), and glial fibrillary protein (GFAP).

Results

The CI-NAD and CI-AD groups had significantly lower scores than the CU group for all cognitive domains (p &lt; 0.043). Associations of MGBA modulators with cognitive functioning included pro-inflammatory cytokines, markers of endothelial dysfunction or overexpressed in response to infection in both groups of patients (|ρ| &gt; 0.33, ps &lt; 0.042). In the CU and CI-AD pooled group, lower cognitive functioning was specifically associated with higher abundance of Dialister and Clostridia_UCG-014, higher levels of LPS and with all neurodegeneration markers (|ρ| &gt; 0.32, p &lt; 0.048 for all). In the CU and CI-NAD pooled group, lower cognitive performance was associated with lower abundance of Acetonema, higher abundance of Bifidobacterium, [Eubacterium]_coprostanoligenes_group and Collinsella, and higher levels of vascular changes (|ρ| &gt; 0.30, p &lt; 0.049).

Discussion

These results support the hypothesis that gut dysbiosis and MGBA mediators may have distinct effects on cognitive functioning and different mechanisms of action depending on the disease.

Investigating Causal Links Between Gut Microbiota and Neurological Disorders via Genome-Wide Association Studies

Many reports have highlighted the involvement of the gut microbiome in the occurrence, progression, and outcomes of neurological disorders. However, current reports are somewhat chaotic, especially concerning whether the gut microbiota has a causal effect on various neurological diseases. Furthermore, whether there is a common mechanism involving gut microbial communities in these neurological disorders has not to be revealed. In this study, we leveraged data from the largest-scale genome-wide association study (GWAS) by the MiBioGen consortium, which includes genetic and microbial composition data from 18,340 individuals spanning 24 cohorts. We utilized single-nucleotide polymorphisms (SNPs) associated with the gut microbiome as instrumental variables (IVs) in Mendelian randomization (MR) analyses. These IVs were rigorously selected based on their genome-wide and locus-wide significance to ensure robust causal inference. Our study established robust associations between specific gut microbiota and various neurological disorders using MR. We systematically depicted the bacteria with causal relationships in all diseases, covering the levels of phylum, class, order, family, and genus. We identified 34 bacterial species as significant risk or protective factors across disorders, including two main phylum levels such as Firmicutes (22 species) and Proteobacteria (8 species), as well as Bacteroidetes (2 species), Actinobacteria (1 species), and Verrucomicrobiota (1 species). At the family level of bacteria, we found that Lachnospiraceae and Ruminococcaceae are the most related to these 11 diseases and they may play different roles in the same disease.

The efficacy and safety of auricular acupoint therapy on treating functional dyspepsia with insomnia: study protocol for a randomized controlled trial

Background

Functional dyspepsia (FD) is a prevalent health issue currently lacking optimal treatment options, with its global incidence rate increasing in recent years. Clinical studies have recently focused on the application of auriculotherapy in functional gastrointestinal disorders that are accompanied by negative emotions. However, few randomized controlled trials have investigated the use of auriculotherapy for FD patients with insomnia, leaving the therapeutic efficacy and safety largely undefined. This study aims to evaluate the clinical efficacy and safety of auriculotherapy in treating FD patients with insomnia.

Methods and analysis

This study is a single-center, randomized controlled clinical trial involving 80 patients with FD and insomnia. Using a central randomization system, the subjects are randomly assigned to the auricular acupressure group or the sham auricular acupressure group at a 1:1 ratio, with the auricular acupressure group targeting the concha region and the sham auricular acupressure group targeting the earlobe region. The primary outcome is the response rate at 2 weeks, and the secondary outcomes include the response rate at 8 weeks, sleep data assessed by actigraphy, modified Functional Dyspepsia Symptom Diary, short form-Nepean Dyspepsia Index, Self-rated Anxiety Scale, Self-rated Depression Scale, High Arousal Scale, and Heart Rate Variability. Efficacy results will be evaluated at baseline and at 2 and 8 weeks after treatment. Adverse events will be monitored throughout the study observation period.

Discussion

The results of this trial are anticipated to validate the efficacy and safety of auriculotherapy in improving symptoms of FD and insomnia, as well as in reducing negative emotional states.

Clinical trial registration

ClinicalTrials.gov, NCT06466044. Registered 14th May 2024, https://register.clinicaltrials.gov.

The "brain-gut" mechanism of postherpetic neuralgia: a mini-review

Postherpetic neuralgia (PHN), a representative type of neuropathic pain, has attracted much research on its diagnosis and therapy at the molecular level. Interestingly, this study based on the brain-gut axis provided a novel point of view to interpret the mechanism of PHN. Past neuroanatomical and neuroimaging studies of pain suggest that the prefrontal cortex, anterior cingulate cortex, amygdala, and other regions of the brain may play crucial roles in the descending inhibition of PHN. Dominant bacterial species in patients with PHN, such as Lactobacillus, generate short-chain fatty acids, including butyrate. Evidence indicates that disturbance of some metabolites (such as butyrate) is closely related to the development of hyperalgesia. In addition, tryptophan and 5-HT in the intestinal tract act as neurotransmitters that regulate the descending transmission of neuropathic pain signals. Concurrently, the enteric nervous system establishes close connections with the central nervous system through the vagus nerve and other pathways. This review aims to investigate and elucidate the molecular mechanisms associated with PHN, focusing on the interplay among PHN, the gut microbiota, and relevant metabolites while scrutinizing its pathogenesis.

Psycho-gastroenterological profile of an Italian population of children with disorders of gut-brain interaction: A case-control study

BACKGROUND

Disorders of gut-brain interaction (DGBI) are common, but knowledge about their physiopathology is still poor, nor valid tools have been used to evaluate them in childhood.

AIM

To develop a psycho-gastroenterological questionnaire (PGQ) to assess the psycho-gastroenterological profile and social characteristics of a pediatric population with and without DGBI.

METHODS

One hundred and nineteen Italian children (age 11-18) were included: 28 outpatient patients with DGBI (Rome IV criteria) and 91 healthy controls. They filled the PGQ, faces pain scale revised (FPS-R), Bristol stool chart, gastrointestinal symptoms rating scale, state-trait anxiety inventory, Toronto alexithymia scale 20, perceived self-efficacy in the management of negative emotions and expression of positive emotions (APEN-G, APEP-G), irritable bowel syndrome-quality of life questionnaire, school performances, tobacco use, early life events, degree of digitalization.

RESULTS

Compared to controls, patients had more medical examinations (35% of them went to the doctor more than five times), a higher school performance (23% vs 13%, P < 0.05), didn’t use tobacco (never vs 16%, P < 0.05), had early life events (28% vs 1% P < 0.05) and a higher percentage of pain classified as 4 in the FPS-R during the examination (14% vs 7%, P < 0.05).

CONCLUSION

Pediatric outpatients with DGBI had a higher prevalence of early life events, a lower quality of life, more medical examinations rising health care costs, lower anxiety levels.

Enantioselective disruption of circadian rhythm behavior in goldfish (Carassius auratus) induced by chiral fungicide triadimefon at environmentally-relevant concentration

The pollution of triadimefon (TDF) fungicides significantly hinders the "One Health" frame achievement. However, the enantioselective effects of chiral TDF on the circadian rhythm of fish remained unclear. Herein, TDF enantiomers (R(-)-TDF and S(+)-TDF) and racemic Rac-TDF were selected to investigate their enantioselective effects and mechanisms on circadian rhythm of goldfish (Carassius auratus) at an environmentally-relevant concentration (100 µg L⁻¹). S(+)-TDF reduced the diurnal-nocturnal differences in schooling behavior more strongly than R(-)-TDF, proving the enantioselectively weakened circadian rhythm of goldfish by TDF. S(+)-TDF more preferentially bioaccumulated in goldfish than R(-)-TDF, mainly contributed to the enantioselectively disrupted circadian rhythm. On one hand, TDF enantiomers in brains differentially inhibited neuronal activity, leading to cholinergic system dysfunction. On the other hand, TDF enantiomers in intestines differentially disrupted intestinal barriers, thus potentially dysregulating the "brain-gut" axis. Importantly, the commercial probiotics alleviated the behavioral disorder, indirectly confirming that the dysbiosis of intestinal bacteria contributed to the TDF-induced circadian rhythm disruption. These findings provide novel insights into the enantioselective disruption of fish circadian rhythm behaviors by chiral fungicides at enantiomer levels, and offer novel strategies for early assessing the ecological risks of chiral agrochemicals in aquatic ecosystems.

Impact of probiotic supplements on behavioural and gastrointestinal symptoms in children with autism spectrum disorder: A randomised controlled trial

OBJECTIVE

To investigate whether probiotic supplementation can improve behavioural and gastrointestinal (GI) symptoms in children with autism spectrum disorder (ASD) aged 2-9 years and further explore the correlation between these symptoms.

DESIGN

Single-blinded, randomised, placebo-controlled study.

SETTING

Five developmental paediatric outpatient clinics of 'Continua Kids'.

PATIENTS

Children aged 2-9 years diagnosed with ASD along with their caregivers.

INTERVENTIONS

Probiotic or placebo sachet reconstituted in 50 mL of lukewarm milk/water, taken two times per day for 3 months.

MAIN OUTCOME MEASURES

Change in behavioural (measured by Social Responsiveness Scale-2 (SRS-2) and Aberrant Behaviour Checklist-2 (ABC-2) tools) and GI (measured by GI Severity Index (GSI) score) symptoms after receiving intervention for 3 months.

RESULTS

A total of 180 children with ASD were enrolled in the study (probiotic group: 90 and placebo group: 90). All children completed the study. The probiotic group showed a significant reduction in behavioural symptom severity as measured by the SRS-2 tool (47.77% vs 23.33%; p=0.000) compared with the placebo. Probiotic-treated children demonstrated significant reductions in severe symptoms, including social withdrawal/lethargy (40%), stereotypic behaviour (37.77%), hyperactivity (34.44%) and inappropriate speech (32.22%) post-intervention (p=0.000). They also had marked improvements in constipation (p=0.003) and diarrhoea (p=0.043) compared with the placebo group. Both groups exhibited a statistically significant correlation between behavioural and GI symptoms.

CONCLUSIONS

Probiotic supplementation improved behavioural and GI symptoms in children with ASD with no adverse effects. Both symptoms were significantly correlated. However, these results need to be validated in a larger sample size.

TRIAL REGISTRATION NUMBER

CTRI/2021/11/038213.

Advancements in the investigation of gut microbiota-based strategies for stroke prevention and treatment

Stroke represents a predominant cause of mortality and disability on a global scale, impacting millions annually and exerting a considerable strain on healthcare systems. The incidence of stroke exhibits regional variability, with ischemic stroke accounting for the majority of occurrences. Post-stroke complications, such as cognitive impairment, motor dysfunction, and recurrent stroke, profoundly affect patients' quality of life. Recent advancements have elucidated the microbiota-gut-brain axis (MGBA), underscoring the complex interplay between gut health and brain function. Dysbiosis, characterized by an imbalance in gut microbiota, is significantly linked to an elevated risk of stroke and unfavorable outcomes. The MGBA plays a crucial role in modulating immune function, neurotransmitter levels, and metabolic byproducts, which may intensify neuroinflammation and impair cerebral health. This review elucidates the role of MGBA in stroke pathophysiology and explores potential gut-targeted therapeutic strategies to reduce stroke risk and promote recovery, including probiotics, prebiotics, pharmacological interventions, and dietary modifications. However, the current prevention and treatment strategies based on intestinal flora still face many problems, such as the large difference of individual intestinal flora, the stability of efficacy, and the long-term safety need to be considered. Further research needs to be strengthened to promote its better application in clinical practice.

Molecules-mediated bidirectional interactions between microbes and human cells

Complex molecules-mediated interactions, which are based on the bidirectional information exchange between microbes and human cells, enable the defense against diseases and health maintenance. Recently, diverse single-direction interactions based on active metabolites, immunity factors, and quorum sensing signals have largely been summarized separately. In this review, according to a simplified timeline, we proposed the framework of Molecules-mediated Bidirectional Interactions (MBI) between microbe and humans to decipher and understand their intricate interactions systematically. About the microbe-derived interactions, we summarized various molecules, such as short-chain fatty acids, bile acids, tryptophan catabolites, and quorum sensing molecules, and their corresponding human receptors. Concerning the human-derived interactions, we reviewed the effect of human molecules, including hormones, cytokines, and other circulatory metabolites on microbial characteristics and phenotypes. Finally, we discussed the challenges and trends for developing and deciphering molecule-mediated bidirectional interactions and their potential applications in the guard of human health.

Significance of the gut tract in the therapeutic mechanisms of polydopamine for acute cerebral infarction: neuro-immune interaction through the gut-brain axis

Background

Recent research has made significant progress in elucidating gastrointestinal complications following acute cerebral infarction (ACI), which includes disorders in intestinal motility and dysbiosis of the gut microbiota. Nevertheless, the role of the gut (which is acknowledged as being the largest immune organ) in the immunoreactive effects of polydopamine nanoparticles (PDA) on acute ischemic stroke remains inadequately understood. In addition to its function in nutrient absorption, the gut acts as a protective barrier against microbes. Systemic immune responses, which are triggered by the disruption of gut barrier integrity, are considered as one of the mechanisms underlying acute ischemic stroke, with the gut-brain axis (GBA) playing a pivotal role in this process.

Methods

In this study, we used a PDA intervention in an ACI model to investigate ACI-like behavior, intestinal barrier function, central and peripheral inflammation, and hippocampal neuron excitability, thus aiming to elucidate the mechanisms through which PDA improves ACI via the GBA.

Results

Our findings indicated that as ACI mice experienced dysbiosis of the gut microbiota and intestinal barrier damage, the levels of proinflammatory factors in the serum and brain significantly increased. Additionally, the activation of astrocytes in the hippocampal region and neuronal apoptosis were observed in ACI mice. Importantly, our study is the first to provide evidence demonstrating that PDA effectively suppresses the neuroimmune interactions of the gut-brain axis and significantly improves intestinal epithelial barrier integrity.

Conclusion

We hope that our discoveries will serve as a foundation for further explorations of the therapeutic mechanisms of PDA in ACI, particularly in elucidating the protective roles of gut microbiota and intestinal barrier function, as well as in the development of more targeted clinical interventions for ACI.

The Power of Exercise: Unlocking the Biological Mysteries of Peripheral-Central Crosstalk in Parkinson's Disease

BACKGROUND

Exercise is a widely recognized non-pharmacological treatment for Parkinson's Disease (PD). The bidirectional regulation between the brain and peripheral organs has emerged as a promising area of research, with the mechanisms by which exercise impacts PD closely linked to the interplay between peripheral signals and the central nervous system.

AIM OF REVIEW

This review aims to summarize the mechanisms by which exercise influences peripheral-central crosstalk to improve PD, discuss the molecular processes mediating these interactions, elucidate the pathways through which exercise may modulate PD pathophysiology, and identify directions for future research.

KEY SCIENTIFIC CONCEPTS OF REVIEW

This review examines how exercise-induced cytokine release promotes neuroprotection in PD. It discusses how exercise can stimulate cytokine secretion through various pathways, including the gut-brain, muscle-brain, liver-brain, adipose-brain, and bone-brain axes, thereby alleviating PD symptoms. Additionally, the potential contributions of the heart-brain, lung-brain, and spleen-brain axes, as well as multi-axis crosstalk-such as the brain-gut-muscle and brain-gut-bone axes-are explored in the context of exercise therapy. The study highlights the need for further research into peripheral-central crosstalk and outlines future directions to address challenges in clinical PD therapy.

Investigating blood-brain barrier penetration and neurotoxicity of natural products for central nervous system drug development

Natural Products (NPs) are increasingly utilized worldwide for their potential therapeutic benefits, including central nervous system (CNS) disorders. Studies have shown açai berries mitigating Parkinson's disease progression through dopaminergic neuroprotection via Nrf-2 HO-1 pathways. Ashwagandha, an evergreen shrub, has shown potential as a therapeutic for neurodegenerative disorders via axonal regeneration in Aβ25-35-treated cortical neurons in vitro. In most cases, promising NPs are tested using in vitro assays or simpler systems during the early stages of drug discovery. However, a critical challenge lies in the lack of data on blood-brain barrier (BBB) penetration, which is a significant determinant for the successful development of CNS drugs. Our first goal was to test our in-house NP constituent library via the Parallel Artificial Membrane Permeability Assay (PAMPA-BBB), with the aim of understanding their BBB-penetration potential. Of the constituents tested, 255 were found to have moderate to high BBB permeability. Our next goal was to understand if these compounds could exhibit CNS toxicity. Neuronal viability and neurite outgrowth assays were performed with this subset to identify compounds with neurotoxicity potential. Around 35% of compounds tested showed neurite outgrowth inhibition. The habitual and widespread consumption of NPs underscores the importance of subjecting this subset of compounds to additional testing and validation in vivo to ascertain their potential detrimental effects. Understanding BBB permeability and assessing neurotoxicity mechanisms of NPs will significantly benefit the CNS drug discovery community.

Discovery of the microbiota-gut-brain axis mechanisms of acupuncture for amnestic mild cognitive impairment based on multi-omics analyses: A pilot study

OBJECTIVES

Acupuncture is a promising therapy for amnestic mild cognitive impairment (aMCI). Growing evidence suggest that alterations in the microbiota-gut-brain (MGB) axis contribute to the development and progression of aMCI. However, little is known about whether and how acupuncture change the MGB axis of aMCI individuals.

METHODS

This was a randomized, controlled, clinical trial. Forty patients with aMCI were randomly allocated to either the acupuncture group or the waitlist group. The primary outcome was the change in the Alzheimer's Disease Assessment Scale-Cognitive Scale (ADAS-Cog) score. In addition, multi-omics was performed to detect changes in brain function, gut microbiota, and serum metabolites. Generalized estimating equations were used to estimate the outcomes, and correlational analyses were performed to explore the relationships between the clinical and multi-omics data.

RESULTS

Compared to a mean baseline to week 12 change of -3.94 in the acupuncture group, the mean change in the waitlist group was 1.72 (net difference, -5.66 [95 % CI, -6.98 to -4.35]). Compared to the waitlist group, acupuncture's MGB axis modulatory effect exhibited altered the regional homogeneity values of Frontal_Med_Orb_L, Cingulum_Mid_L, and Frontal_Sup_Medial_L, relative abundance of gut Ruminococcus_sp_AF43_11 and s_Eubacterium_coprostanoligenes, and levels of serum (11E,15Z)-9,10,13-trihydroxyoctadeca-11,15-dienoic acid, dipropylene glycol dimethyl ether, N6-Me-dA, and DPK, which correlated with changes in ADAS-Cog scores.

CONCLUSIONS

Our data imply that acupuncture ameliorates overall cognitive function, along with changes in brain activity, gut microbiota, and serum metabolites, providing preliminary evidence of the mechanisms acting through the MGB axis underlying the effects of acupuncture on aMCI.

The role of the gut microbiome in disorders of gut-brain interaction

Disorders of Gut-Brain Interaction (DGBI) are widely prevalent and commonly encountered in gastroenterology practice. While several peripheral and central mechanisms have been implicated in the pathogenesis of DGBI, a recent body of work suggests an important role for the gut microbiome. In this review, we highlight how gut microbiota and their metabolites affect physiologic changes underlying symptoms in DGBI, with a particular focus on their mechanistic influence on GI transit, visceral sensitivity, intestinal barrier function and secretion, and CNS processing. This review emphasizes the complexity of local and distant effects of microbial metabolites on physiological function, influenced by factors such as metabolite concentration, duration of metabolite exposure, receptor location, host genetics, and underlying disease state. Large-scale in vitro work has elucidated interactions between host receptors and the microbial metabolome but there is a need for future research to integrate such preclinical findings with clinical studies. The development of novel, targeted therapeutic strategies for DGBI hinges on a deeper understanding of these metabolite-host interactions, offering exciting possibilities for the future of treatment of DGBI.

Disorders of gut-brain interaction through the lens of polyvagal theory

This paper introduces a metric capable of tracking a hypothetical brainstem "switching" mechanism involved in regulating the afferent influence of blood pressure on the vagal efferent control of heart rate. In theory, this metric could be applied to evaluate the "efficiency" of brainstem pathways involved in common mechanisms of autonomic function involving the vagal influences on the gut as well as the heart. Thus, by exploring the dynamic "efficiency" of the brainstem feedback circuit linking heart rate to posture, a clinically relevant index of vagal flexibility might be extracted that would provide a generalizable window into the vagal regulation of both the heart and gut. Recent research supports this contention and has documented that this metric, VE, appears to covary with disorders of the gut. Clinical application of this metric might identify individual vulnerabilities that frequently reflect symptoms assumed to have features of a dysregulated autonomic nervous system (i.e., dysautonomia). If this is confirmed by additional research, then this objective measure of neural regulation of autonomic function might provide insight into the pathogenesis of disorders of gut-brain interaction.

The association between dietary dark green vegetable intake and cognitive function in US older adults

Dark green vegetables include dark green leafy vegetables and broccoli. They are sources of many essential nutrients, including vitamins A, B and C, folate, fibre, carotenoids and flavonoids. This study aimed to explore the association between dietary dark green vegetable intake and cognitive function in US older adults. We included 2344 older adults (≥60 years old) from the National Health and Nutrition Examination Survey (NHANES) 2011-2014 cycles. Dark green vegetable consumption was assessed using a continuous variable (cups/day) and two categorical variables. The first categorical variable classified participants into non-consumers and consumers based on whether they consumed dark green vegetables. The second categorical variable grouped participants into four levels of dark green vegetable consumption (non-consumers, consumers with low intakes, consumers with moderate intakes and consumers with high intakes). We used five continuous variables with non-normal distribution to assess cognitive function, including a composite z-score and the standardised scores of four individual cognitive tests. The four cognitive tests included the Immediate Recall Test (IRT), the Delayed Recall Test (DRT), the Animal Mobility Test (AFT) and the Digit Symbol Substitution Test (DSST). The standardised scores of the four cognitive tests were calculated using the mean and standard deviation of each cognitive test score. The composite z-score was calculated by averaging the standardised scores of four cognitive tests to evaluate global cognition. We used multiple linear regression models to examine the association between dietary dark green vegetable intake and cognitive function. Our findings indicated that dark green vegetable intake was positively associated with global cognition (β [95% CI]: 0.17 [0.04, 0.30]; p = 0.016) and IRT (β [95% CI]: 0.26 [0.08, 0.43]; p = 0.009) and DRT (β [95% CI]: 0.21 [0.05, 0.36]; p = 0.012) standardised scores. Individuals with high intake of dark green vegetables showed notably better global cognition (β [95% CI]: 0.16 [0.05, 0.28]; p = 0.010) and showed higher IRT (β [95% CI]: 0.22 [0.07, 0.38]; p = 0.010) and DRT standardised scores (β [95% CI]: 0.21 [0.07, 0.36]; p = 0.007) compared with the non-consumers. Blood neutrophil counts mediated the cognitive benefits of dark green vegetables (Proportion: 9.5%, p = 0.006). In conclusion, our findings suggest that dark green vegetable consumption may have favourable effects on cognitive function in US older adults, especially on immediate and delayed learning abilities. The underlying mechanisms include the ability of dark green vegetables to reduce blood neutrophil levels, an indicator of decreased systemic inflammation. Increasing dietary intake of dark green vegetables may be a beneficial intervention to improve cognitive health in the older US population.

Intermittent fasting and neurodegenerative diseases: Molecular mechanisms and therapeutic potential

Neurodegenerative disorders are straining public health worldwide. During neurodegenerative disease progression, aberrant neuronal network activity, bioenergetic impairment, adaptive neural plasticity impairment, dysregulation of neuronal Ca2+ homeostasis, oxidative stress, and immune inflammation manifest as characteristic pathological changes in the cellular milieu of the brain. There is no drug for the treatment of neurodegenerative disorders, and therefore, strategies/treatments for the prevention or treatment of neurodegenerative disorders are urgently needed. Intermittent fasting (IF) is characterized as an eating pattern that alternates between periods of fasting and eating, requiring fasting durations that vary depending on the specific protocol implemented. During IF, depletion of liver glycogen stores leads to the production of ketone bodies from fatty acids derived from adipocytes, thereby inducing an altered metabolic state accompanied by cellular and molecular adaptive responses within neural networks in the brain. At the cellular level, adaptive responses can promote the generation of synapses and neurons. At the molecular level, IF triggers the activation of associated transcription factors, thereby eliciting the expression of protective proteins. Consequently, this regulatory process governs central and peripheral metabolism, oxidative stress, inflammation, mitochondrial function, autophagy, and the gut microbiota, all of which contribute to the amelioration of neurodegenerative disorders. Emerging evidence suggests that weight regulation significantly contributes to the neuroprotective effects of IF. By alleviating obesity-related factors such as blood-brain barrier dysfunction, neuroinflammation, and β-amyloid accumulation, IF enhances metabolic flexibility and insulin sensitivity, further supporting its potential in mitigating neurodegenerative disorders. The present review summarizes animal and human studies investigating the role and underlying mechanisms of IF in physiology and pathology, with an emphasis on its therapeutic potential. Furthermore, we provide an overview of the cellular and molecular mechanisms involved in regulating brain energy metabolism through IF, highlighting its potential applications in neurodegenerative disorders. Ultimately, our findings offer novel insights into the preventive and therapeutic applications of IF for neurodegenerative disorders.

Exploring the CDCA-Scd1 Axis: Molecular Mechanisms Linking the Colitis Microbiome to Neurological Deficits

Inflammatory bowel disease is a risk factor for brain dysfunction; however, the underlying mechanisms remain largely unknown. In this study, we aimed to explore the potential molecular mechanisms through which intestinal inflammation affects brain function and to verify these mechanisms. Mice were treated with multiple cycles of 1% w/v dextran sulfate sodium (DSS) in drinking water to establish a chronic colitis model. Behavioral tests were conducted using the open field test (OFT), tail suspension test (TST), forced swimming test (FST), and Morris water maze test (MWM). Brain metabolomics, transcriptomics, and proteomics analyses were performed, and key target proteins were verified using qPCR and immunofluorescence. Four cycles of DSS administration induced colitis, anxiety, depression, and spatial memory impairment. The integrated multi-omics characterization of colitis revealed decreased brain chenodeoxycholic acid (CDCA) levels as well as reduced stearoyl-CoA desaturase (Scd1) gene and protein expression. Transplantation of the colitis microbiome resulted in anxiety, depression, impaired spatial memory, reduced CDCA content, decreased Scd1 gene and protein expression, and lower concentrations of monounsaturated fatty acids (MUFAs), palmitoleate (C16:1), and oleate (C18:1) in the brain. In addition, CDCA supplementation improved DSS-induced colitis, alleviated depression and spatial memory impairment, and increased Scd1 gene and protein expression as well as MUFA levels in the brain. The gut microbiome induced by colitis contributes to neurological dysfunction, possibly through the CDCA-Scd1 signaling axis. CDCA supplementation alleviates colitis and depressive behavior, likely by increasing Scd1 expression in the brain.

Recent insights and advances in gut microbiota's influence on host antiviral immunity

A diverse array of microbial organisms colonizes the human body, collectively known as symbiotic microbial communities. Among the various pathogen infections that hosts encounter, viral infections represent one of the most significant public health challenges worldwide. The gut microbiota is considered an important biological barrier against viral infections and may serve as a promising target for adjuvant antiviral therapy. However, the potential impact of symbiotic microbiota on viral infection remains relatively understudied. In this review, we discuss the specific regulatory mechanisms of gut microbiota in antiviral immunity, highlighting recent advances in how gut microbiota regulate the host immune response, produce immune-related molecules, and enhance the host's defense against viruses. Finally, we also discuss the antiviral potential of oral probiotics.

Quinoa Saponin Ameliorates Lipopolysaccharide-Induced Behavioral Disorders in Mice by Inhibiting Neuroinflammation, Modulating Gut Microbiota, and Counterbalancing Intestinal Inflammation

Triterpenoids derived from plants are a promising class of natural antidepressants. This research focused on the therapeutic potential of quinoa saponin (QS) in alleviating lipopolysaccharide (LPS)-induced anxiety and depressive-like behaviors in mice. The most abundant saponin fraction, QS-3, was isolated from QS extracts, and its major saponin components and chemical structure were elucidated. Six pentacyclic triterpene saponins and three tetracyclic triterpene saponins were identified in QS-3, with phytolaccagenin and oleanolic acid being the dominant sapogenins. In vivo studies demonstrated that QS significantly mitigated LPS-induced anxiety and depressive-like behaviors in mice, enhanced the levels of neurotrophic proteins, key synaptic proteins, and neurotransmitters, and restored synaptic function and neuronal damage. Furthermore, QS inhibited neuroinflammation by curtailing the activity of the TLR4/MyD88/NF-κB pathway and modulating microglial phenotypes. Notably, QS also ameliorated colonic inflammation by promoting gut microbiota homeostasis and increasing short-chain fatty acids (SCFAs) production, which contributed to the improvement of anxiety and depressive behaviors in mice. Our findings suggest that QS holds potential as a natural dietary supplement for the treatment and prevention of anxiety and depression, possibly through its modulation of gut-brain axis dynamics and suppression of the activation of the TLR4/MyD88/NF-κB pathway.

Impact of fracture fixation surgery on cognitive function and the gut microbiota in mice with a history of stroke

Perioperative cognitive dysfunction is a common complication in stroke patients undergoing secondary surgeries. This study investigated the effects of tibial fracture internal fixation (TFIF) surgery on cognitive function and the gut microbiota in mice with a history of stroke. Using the middle cerebral artery occlusion method to induce stroke, we assessed cognitive function via the fear conditioning test and analyzed the gut microbiota through 16S rRNA sequencing. Compared with those in the normal and stroke groups, the cognitive function of the mice in the stroke group that underwent TFIF surgery was significantly impaired. Gut microbiota analysis revealed significant changes in beta diversity, but not in alpha diversity, in these mice. Additionally, TFIF surgery increased microglial activation and IL-1β and lipopolysaccharide (LPS) levels in the brain while reducing α-defensin levels and increasing IL-1β and LPS levels in the colon. These results suggest that TFIF surgery exacerbates cognitive impairment in stroke mice, possibly through alterations in the gut microbiota that impair intestinal defense and promote inflammation. This study highlights the critical role of the gut microbiome in cognitive function and perioperative outcomes, offering insights into potential therapeutic strategies for perioperative cognitive dysfunction in stroke patients.

Brain Morphometry and Cognitive Features in the Prediction of Irritable Bowel Syndrome

Background/Objectives: Irritable bowel syndrome (IBS) is a gut-brain disorder characterized by abdominal pain, altered bowel habits, and psychological distress. While brain-gut interactions are recognized in IBS pathophysiology, the relationship between brain morphometry, cognitive function, and clinical features remains poorly understood. The study aims to conduct the following: (i) to replicate previous univariate morphometric findings in IBS patients and conduct software comparisons; (ii) to investigate whether multivariate analysis of brain morphometric measures and cognitive performance can distinguish IBS patients from healthy controls (HCs), and evaluate the importance of structural and cognitive features in this discrimination. Methods: We studied 49 IBS patients and 29 HCs using structural brain magnetic resonance images (MRIs) and the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). Brain morphometry was analyzed using FreeSurfer v6.0.1 and v7.4.1, with IBS severity assessed via the IBS-Severity Scoring System. We employed univariate, multivariate, and machine learning approaches with cross-validation. Results: The FreeSurfer version comparison revealed substantial variations in morphometric measurements, while morphometric measures alone showed limited discrimination between groups; combining morphometric and cognitive measures achieved 93% sensitivity in identifying IBS patients (22% specificity). The feature importance analysis highlighted the role of subcortical structures (the hippocampus, caudate, and putamen) and cognitive domains (recall and verbal skills) in group discrimination. Conclusions: Our comprehensive open-source framework suggests that combining brain morphometry and cognitive measures improves IBS-HC discrimination compared to morphometric measures alone. The importance of subcortical structures and specific cognitive domains supports complex brain-gut interaction in IBS, emphasizing the need for multimodal approaches and rigorous methodological considerations.

Comparative Analysis of Gut Microbiota in Patients with Irritable Bowel Syndrome and Healthy Controls

Background/Objectives: Growing evidence highlights the pivotal role of gut dysbiosis in the pathophysiology of irritable bowel syndrome (IBS). Despite this, the identification of an "IBS microbiota signature" remains elusive, primarily due to the influence of genetic, dietary, and environmental factors. To address these confounding variables, it is critical to perform comparative analyses using a control group derived from the same community as the IBS patients. This study aimed to evaluate and contrast the gut microbiota composition of IBS patients with healthy controls. Methods: We compared the gut microbiota from stool samples of 25 IBS patients diagnosed according to the Rome IV criteria, and 110 healthy subjects without acute or chronic diseases and not on continuous medication. The high-throughput sequencing of the V3-V4 regions of the 16S rRNA gene was conducted for microbiota analysis. Results: The IBS gut microbiota was richer but exhibited lower alpha diversity compared to the control group, suggesting simplification and imbalance. A beta diversity analysis revealed overall compositional differences between the two groups. A heat tree analysis highlighted key IBS-associated changes, including a decrease in Firmicutes, mainly due to Clostridia, and an increase in Bacteroidota, driven by an expansion of Bacteroidales families. Differential expression analyses identified important genera within these taxa like Bacteroides, Faecalibacterium, and Blautia, which could serve as microbiota-based biomarkers for IBS. Conclusions: Our results reveal both statistically and clinically significant differences in gut microbiota composition and diversity between IBS patients and healthy controls from the same community. These findings provide a deeper understanding of how alterations in the gut microbiota may contribute to IBS symptoms, offering new insights into the diagnosis and potential treatments.

Multifluid Metabolomics Identifies Novel Biomarkers for Irritable Bowel Syndrome

Background/Objectives: Irritable bowel syndrome (IBS) is a complex disorder affecting 10% of the global population, but the underlying mechanisms remain poorly understood. By integrating multifluid metabolomics, we aimed to identify metabolite markers of IBS in a large population-based cohort. Methods: We included individuals from TwinsUK with and without IBS, ascertained using the Rome III criteria, and analysed serum (232 cases, 1707 controls), urine (185 cases, 1341 controls), and stool (186 cases, 1284 controls) metabolites (Metabolon Inc.). Results: After adjusting for covariates, and multiple testing, 44 unique metabolites (25 novel) were associated with IBS, including lipids, amino acids, and xenobiotics. Androsterone sulphate, a sulfated steroid hormone precursor, was associated with lower odds of IBS in both urine (0.69 [95% confidence interval = 0.56-0.85], p = 2.34 × 10-4) and serum (0.75 [0.63-0.90], p = 1.54 × 10-3. Moreover, suberate (C8-DC) was associated with higher odds of IBS in serum (1.36 [1.15-1.61]; p = 1.84 × 10-4) and lower odds of IBS in stool (0.76 [0.63-0.91]; p = 2.30 × 10-3). On the contrary, 32 metabolites appeared to be fluid-specific, including indole, 13-HODE + 9-HODE, pterin, bilirubin (E,Z or Z,Z), and urolithin. The remaining 10 metabolites were associated with IBS in one fluid with suggestive evidence (p < 0.05) in another fluid. Finally, we identified androgenic signalling, dicarboxylates, haemoglobin, and porphyrin metabolism to be significantly over-represented in individuals with IBS compared to controls. Conclusions: Our results highlight the utility of a multi-fluid approach in IBS research, revealing distinct metabolic signatures across biofluids.

Benzimidazole Fungicide Carbendazim Induces Gut Inflammation through the TLR5/NF-κB Pathway in Grass Carp

Fungicides have been increasingly used across various sectors, including agriculture and textiles. The biocidal properties of fungicides may negatively impact the stability of intestinal microbiota, thereby posing a threat to intestinal health. In this study, we investigated the mechanisms of intestinal damage and functional abnormalities in grass carp following a 42-day exposure to the widely used fungicide carbendazim at environmentally relevant concentrations (0.2 to 20 μg/L). Histopathological observations, mRNA and protein expression analyses, biochemical analysis, quantification of short-chain fatty acids (SCFAs), cytokines, lipopolysaccharide (LPS), and 16S ribosomal ribonucleic acid (rRNA), as well as internal transcribed spacer (ITS) sequencing, were performed. At environmentally relevant concentrations, carbendazim strongly induced intestinal inflammation, leading to increased transcriptional and translational levels of genes involved in the toll-like receptor five (TLR5)/nuclear factor kappa B (NF-κB) pathway, including TLR5, NF-κB, interleukin-1 beta (IL-1β), and tumor necrosis factor-alpha (TNFα). Additionally, carbendazim damaged intestinal barriers and reduced the expression of tight junction proteins (e.g., occludin and zonula occludens-1/2), goblet cells, and immunoglobulin M levels, while also disrupting the gut microbiome, leading to intestinal metabolic disorders, particularly decreases in SCFAs and increases in LPS. Treatment with the TLR5 antagonist TH1020 mitigated intestinal inflammation caused by carbendazim, subsequently improving mechanical barrier function. Overall, our findings provide new insights into the toxicological mechanisms underlying intestinal damage caused by carbendazim in grass carp, indicating that carbendazim poses a significant threat to nontarget organisms. Given its widespread detection in the environment, these results underscore the substantial ecological risks to the gut health of fish living in carbendazim-contaminated water bodies.

Targeting Ferroptosis in Parkinson's: Repurposing Diabetes Drugs as a Promising Treatment

This review explores the promising potential of repurposing type 2 diabetes (T2D) medications for the treatment of Parkinson's disease (PD), highlighting the shared pathophysiological mechanisms between these two age-related conditions, such as oxidative stress, mitochondrial dysfunction, and ferroptosis. The overlap suggests that existing diabetes drugs could target the common pathways involved in both conditions. Specifically, the review discusses how T2D medications, including metformin (Met), peroxisome-proliferator-activated receptor gamma (PPAR-γ) agonists, sodium-glucose cotransporter-2 (SGLT2) inhibitors, incretins, and dipeptidyl-peptidase 4 (DPP-4) inhibitors, can improve mitochondrial function, reduce neuroinflammation and oxidative stress, and potentially inhibit ferroptosis. The connection between ferroptosis and existing treatments, including diabetes medication, are only beginning to be explored. The limited data can be attributed also to the complexity of mechanisms involved in ferroptosis and Parkinson's disease and to the fact that the specific role of ferroptosis in Parkinson's disease pathogenesis has not been a primary focus until recent. Despite the promising preclinical evidence, clinical findings are mixed, underscoring the need for further research to elucidate these drugs' roles in neurodegeneration. Repurposing existing diabetes medications that have well-established safety profiles for Parkinson's disease treatment could significantly reduce the time and cost associated with drug development and could offer a more comprehensive approach to managing Parkinson's disease compared to treatments targeting a single mechanism.

Gut Microbiome, Diet and Depression: Literature Review of Microbiological, Nutritional and Neuroscientific Aspects

PURPOSE OF REVIEW

This review explores the intricate relationships among the gut microbiota, dietary patterns, and mental health, focusing specifically on depression. It synthesizes insights from microbiological, nutritional, and neuroscientific perspectives to understand how the gut-brain axis influences mood and cognitive function.

RECENT FINDINGS

Recent studies underscore the central role of gut microbiota in modulating neurological and psychological health via the gut-brain axis. Key findings highlight the importance of dietary components, including probiotics, prebiotics, and psychobiotics, in restoring microbial balance and enhancing mood regulation. Different dietary patterns exhibit a profound impact on gut microbiota composition, suggesting their potential as complementary strategies for mental health support. Furthermore, mechanisms like tryptophan metabolism, the HPA axis, and microbial metabolites such as SCFAs are implicated in linking diet and microbiota to depression. Clinical trials show promising effects of probiotics in alleviating depressive symptoms. This review illuminates the potential of diet-based interventions targeting the gut microbiota to mitigate depression and improve mental health. While the interplay between microbial diversity, diet, and brain function offers promising therapeutic avenues, further clinical research is needed to validate these findings and establish robust, individualized treatment strategies.

Neurological sequelae of long COVID: a comprehensive review of diagnostic imaging, underlying mechanisms, and potential therapeutics

One lingering effect of the COVID-19 pandemic created by SARS-CoV-2 is the emergence of Long COVID (LC), characterized by enduring neurological sequelae affecting a significant portion of survivors. This review provides a thorough analysis of these neurological disruptions with respect to cognitive dysfunction, which broadly manifest as chronic insomnia, fatigue, mood dysregulation, and cognitive impairments with respect to cognitive dysfunction. Furthermore, we characterize how diagnostic tools such as PET, MRI, EEG, and ultrasonography provide critical insight into subtle neurological anomalies that may mechanistically explain the Long COVID disease phenotype. In this review, we explore the mechanistic hypotheses of these neurological changes, which describe CNS invasion, neuroinflammation, blood-brain barrier disruption, and gut-brain axis dysregulation, along with the novel vascular disruption hypothesis that highlights endothelial dysfunction and hypoperfusion as a core underlying mechanism. We lastly evaluate the clinical treatment landscape, scrutinizing the efficacy of various therapeutic strategies ranging from antivirals to anti-inflammatory agents in mitigating the multifaceted symptoms of LC.

The Inflammatory Mechanism of Parkinson's Disease: Gut Microbiota Metabolites Affect the Development of the Disease Through the Gut-Brain Axis

Parkinson's disease is recognized as the second most prevalent neurodegenerative disorder globally, with its incidence rate projected to increase alongside ongoing population growth. However, the precise etiology of Parkinson's disease remains elusive. This article explores the inflammatory mechanisms linking gut microbiota to Parkinson's disease, emphasizing alterations in gut microbiota and their metabolites that influence the disease's progression through the bidirectional transmission of inflammatory signals along the gut-brain axis. Building on this mechanistic framework, this article further discusses research methodologies and treatment strategies focused on gut microbiota metabolites, including metabolomics detection techniques, animal model investigations, and therapeutic approaches such as dietary interventions, probiotic treatments, and fecal transplantation. Ultimately, this article aims to elucidate the relationship between gut microbiota metabolites and the inflammatory mechanisms underlying Parkinson's disease, thereby paving the way for novel avenues in the research and treatment of this condition.

Winnie Mice: A Chronic and Progressive Model of Ulcerative Colitis

Recent trends show a continuous worldwide rise in the incidence of ulcerative colitis (UC), leading to increased interest in its etiology and pathogenesis, which is currently unknown. To gain a better mechanistic understanding of this disease, many mouse models have been developed over the last several years, with variations of dextran sodium sulfate administration representing the most widely employed. The Winnie mouse strain was created through elicited random mutations in Muc2, resulting in a progressive, chronic intestinal inflammation localized to the colon that worsens over time. Moreover, Winnie mice display immunologic and microbiota features that are similar to those that can be found in UC patients. Phenotypically, the presence, albeit rare, of rectal prolapse and other complications impacting quality of life can be observed in Winnie mice, as well as extraintestinal manifestations that are often associated with UC. While Winnie mice are currently less studied compared to other more established models of colitis, much has been discovered in the initial years of its use as a UC-like model. In summary, the use of Winnie mice adds to the growing armamentarium that is required to develop precision-based medicine for its future application in treating complex multifactorial diseases, such as UC.

Altered gut microbiome and serum metabolome profiles associated with essential tremor

The genetic predisposition and environmental factors both trigger the complex neurological dyskinesia of essential tremor (ET). Gut dysbiosis may facilitate the occurrence and development of neurological diseases. Therefore, it is worth exploring the inner connections between gut microbiota and ET. First, the gut microbiota of 19 ET patients and 21 healthy controls (HCs) were analysed with metagenomics approach. Second, the potential linkages between gut microbiome and serum metabolome profiles were explored by integrative analysis. The gut microbiota disorders were present in ET patients. The LEfSe method showed a significant decrease in Bacteroides. The functional analysis revealed that there were differences in gut microbial apoptosis, retinol metabolism, and steroid hormone biosynthesis pathways. The levels of various lipids and lipid-like molecules alter in serum of ET patients, which correlated with altered gut microbial abundance, indicating the alterations in lipid metabolism involved in apoptosis pathway in ET. All of these data point to the gut dysbiosis in ET, and some changed gut microbial species were linked to abnormalities in blood lipid metabolism, which open up new avenues for investigation into the pathophysiology of ET.

Photobiomodulation of gut microbiota with low-level laser therapy: a light for treating neuroinflammation

The gut microbiota is known to interact with various organs in the body, including the central nervous system, through the gut-brain axis. Intestinal dysbiosis can lead to increased peripheral inflammation and, consequently, affect the brain, resulting in neuroinflammation. Photobiomodulation (PBM) has demonstrated positive regulatory effects on the imbalance of certain body functions, including pain, inflammation, immunity, wound healing, and gut microbiota dysbiosis. Therefore, PBM at the intestinal level could help improve intestinal dysbiosis and reestablish cerebral homeostasis. In this context, this study aimed to conduct a narrative review of the literature on the effects of PBM at the intestinal level on intestinal dysbiosis and neuroinflammation. Overall, the findings highlight that PBM modulates the gut microbiota, suggesting it could serve as a therapy for neurological conditions affecting the gut-brain axis. Future research should focus on further elucidating the molecular mechanisms underlying this therapy.

Harnessing Evolution and Biomimetics to Enhance Planetary Health: Kidney Insights

Planetary health encompasses the understanding that the long-term well-being of humanity is intrinsically linked to the health of global ecological systems. Unfortunately, current practices often overlook this principle, leading to a human-oriented (anthropocentric) worldview that has resulted in heightened greenhouse gas emissions, increased heat stress, lack of access to clean water, and pollution, threatening both the environment and health and survival of Homo sapiens and countless other species. One significant consequence of these environmental changes is the exacerbation of inflammatory and oxidative stressors, which not only contributes to common lifestyle diseases but also accelerates the aging process. We advocate for a shift away from our current anthropocentric frameworks to an approach that focuses on nature's solutions that developed from natural selection over the eons. This approach, which encompasses the field of biomimicry, may provide insights that can help protect against an inflammatory phenotype to mitigate physiological and cellular senescence and provide a buffer against environmental stressors. Gaining insights from how animals have developed ingenious approaches to combat adversity through the evolutionary process of natural selection not only provides solutions for climate change but also confronts the rising burden of lifestyle diseases that accumulate with age.

Bacterial and bacterial derivatives-based drug delivery systems: a novel approach for treating central nervous system disorders

INTRODUCTION

Bacteria and their derivatives show great potential as drug delivery systems due to their unique chemotaxis, biocompatibility, and targeting abilities. In CNS disease treatment, bacterial carriers can cross the blood-brain barrier (BBB) and deliver drugs precisely, overcoming limitations of traditional methods. Advances in genetic engineering, synthetic biology, and nanotechnology have transformed these systems into multifunctional platforms for personalized CNS treatment.

AREAS COVERED

This review examines the latest research on bacterial carriers for treating ischemic brain injury, neurodegenerative diseases, and gliomas. Bacteria efficiently cross the blood-brain barrier via active targeting, endocytosis, paracellular transport, and the nose-to-brain route for precise drug delivery. Various bacterial drug delivery systems, such as OMVs and bacterial ghosts, are explored for their design and application. Databases were searched in Google Scholar for the period up to December 2024.

EXPERT OPINION

Future developments in bacterial drug delivery will rely on AI-driven design and high-throughput engineering, enhancing treatment precision. Personalized medicine will further optimize bacterial carriers for individual patients, but challenges such as biosafety, immune rejection, and scalability must be addressed. As multimodal diagnostic and therapeutic strategies advance, bacterial carriers are expected to play a central role in CNS disease treatment, offering novel precision medicine solutions.

Linking dietary fiber to human malady through cumulative profiling of microbiota disturbance

Dietary fiber influences the composition and metabolic activity of microbial communities, impacting disease development. Current understanding of the intricate fiber-microbe-disease tripartite relationship remains fragmented and elusive, urging a systematic investigation. Here, we focused on microbiota disturbance as a robust index to mitigate various confounding factors and developed the Bio-taxonomic Hierarchy Weighted Aggregation (BHWA) algorithm to integrate multi-taxonomy microbiota disturbance data, thereby illuminating the complex relationships among dietary fiber, microbiota, and disease. By leveraging microbiota disturbance similarities, we (1) classified 32 types of dietary fibers into six functional subgroups, revealing correlations with fiber solubility; (2) established associations among 161 diseases, uncovering shared microbiota disturbance patterns that explain disease co-occurrence (e.g., type II diabetes and kidney diseases) and distinct microbiota patterns that discern symptomatically similar diseases (e.g., inflammatory bowel disease and irritable bowel syndrome); (3) designed a body-site-specific microbiota disturbance scoring scheme, computing a disturbance score (DS) for each disease and highlighting the pronounced capacity of Crohn's disease to disturb gut microbiota (DS = 14.01) in contrast with food allergy's minimal capacity (DS = 0.74); (4) identified 1659 fiber-disease associations, predicting the potential of dietary fiber to modulate specific microbiota changes associated with diseases of interest; (5) established murine models of inflammatory bowel disease to validate the preventive and therapeutic effects of arabinoxylan that notably perturbed the Bacteroidetes and Firmicutes phyla, as well as the Bacteroidetes and Lactobacillus genera, aligning with our model predictions. To enhance data accessibility and facilitate targeted dietary intervention development, we launched an interactive webtool-mDiFiBank at https://mdifibank.org.cn/.