The relationship between gut microbiota and inflammatory response, learning and memory in mice by sleep deprivation

Sedative-hypnotic effects of Yiyin Anshen Granule on mice models of insomnia by regulating neurotransmitters, cytokines, and gut microbiota

This study aims to elucidate the pathways through which Yiyin Anshen Granule (YA) exerts sedative-hypnotic effects in a mouse model of sleep deprivation. DL-4-chlorophenylalanine(PCPA)-treated mice received intragastric administration of YA and pentobarbital sodium-induced sleep tests were conducted on days 7, 14, and 29. The levels of key neurotransmitters, cytokines and receptor protein associated with insomnia were measured using enzyme-linked immunosorbent assay (ELISA) and Western blot. Additionally, 16S ribosomal DNA (rDNA) sequencing was performed to assess the impact of YA on gut microbiota, focusing on species abundance and diversity. YA significantly shortened sleep latency (P < 0.01) and prolonged sleep duration (P < 0.01) in sleep-deprived mice, effectively improving circadian rhythm disturbances compared to the model group (MOD). Biochemical analysis revealed that YA restored abnormal neurotransmitter levels in brain tissue, increasing 5-hydroxytryptamine (5-HT), γ-aminobutyric acid (GABA), and γ-aminobutyric acid type A receptor α-1 subunit (GABAARα1) expression (P < 0.01) and reducing the glutamate (Glu)/GABA ratio (P < 0.01). Additionally, the levels of B-cell lymphoma 2 (BCL-2) and interleukin-6 (IL-6) expression were significantly decreased (P < 0.05, 0.01), while interleukin-1 beta (IL-1β) expression increased (P < 0.01). YA treatment also significantly increased gut microbiota abundance and diversity, with microbiome profiles in the YA group being closer than those of diazepam group (DZP) to the control group (CON). Notably, YA reversed the dysbiosis of high-abundance gut microbiota species associated with insomnia at both the family and genus levels (P < 0.05, 0.01). The results of the present study indicated that YA alleviates insomnia symptoms by regulating neurotransmitter and inflammatory cytokines levels, and restoring gut microbia balance. These mechanisms collectively contribute to shortening sleep latency, prolonging sleep duration, and improving sleep quality in a mouse model of insomnia.

Could self-reporting sleep duration become an important tool in the prediction of dementia?

INTRODUCTION

Optimal sleep duration is increasingly recognized as an important determinant of overall health, including cognitive functioning. Studies often report a U- or J-shaped relationship between sleep duration and incident dementia or cognitive deterioration, whereas long sleep, the extremes of sleep duration, and the transition to long sleep were particularly detrimental. In preclinical studies, partial or complete sleep deprivation produced inflammation, oxidative stress, as well as increased tau hyperphosphorylation and amyloid-β burden. In humans, although the findings are less pronounced, they still highlight that transitioning to an excessive sleep duration is associated with neurodegeneration. Moreover, the association between sleep duration and dementia is complex and modified by genetic, psychosocial and lifestyle factors, along with psychiatric and somatic comorbidities.

AREAS COVERED

The purpose of this perspective is to summarize the current knowledge on the association between sleep duration and dementia. It is based on a literature search for meta-analyses of prospective studies with sleep duration as an exposure and dementia as an outcome.

EXPERT OPINION

Sleep duration is a modifiable risk factor for dementia while long sleep may be an early sign of neurodegeneration. Therefore, self-reported sleep duration is an easy-to-use tool for detecting individuals who may be at risk for cognitive deterioration.

Environmental risk factors of inflammatory bowel disease: toward a strategy of preventative health

The pathogenesis of inflammatory bowel disease (IBD) involves a complex interplay between genetic, environmental, and microbial factors. Many of these environmental determinants are modifiable, offering opportunities to prevent disease or delay its onset. Advances in the study of preclinical IBD cohorts offer the potential to identify biomarkers that predict individuals at high risk of developing IBD, enabling targeted environmental interventions aimed at reducing IBD incidence. This review summarizes findings from 79 meta-analyses on modifiable environmental factors associated with the development of IBD. Identified risk factors include smoking, Western diets, ultra-processed foods, and early life antibiotic use, while protective factors include breastfeeding, Mediterranean diets rich in fiber, plant-based foods, and fish, along with an active physical lifestyle. Despite the promise shown by observational data, interventional or randomized controlled studies evaluating the efficacy of modifying environmental risk factors remain limited and mostly focus on dietary intervention. This review aims to inform the design of higher quality interventional and randomized controlled studies for disease prevention while providing actionable guidance to healthcare providers on reducing the risk of developing IBD through environmental modifications.

Effect of improving sleep quality the night before surgery with zolpidem on postoperative gastrointestinal function in patients undergoing laparoscopic partial colorectal resection: a randomized, double-blind, controlled trial

BACKGROUND

Sleep is one of the basic physiological needs of human beings. Preoperative sleep disorders are associated with poor prognosis in surgical patients, and sleep disorders have been shown to be one of the risk factors for gastrointestinal dysfunction. However, there are now few studies to investigate whether improving preoperative sleep disorders can promote the recovery of postoperative gastrointestinal function. This study aimed to investigate the effects and significance of improving preoperative sleep quality with zolpidem on postoperative gastrointestinal function.

METHODS

In this prospective, randomized, double-blind clinical trial, 76 patients undergoing elective laparoscopic partial colorectal resection and with a Pittsburgh Sleep Quality Index (PSQI) score > 5, were randomly divided into two groups. The zolpidem group (Group Z, n = 38) was given a capsule containing 10 mg of zolpidem the night before the operation, and the control group (Group C, n = 38) was given an empty capsule the night before the operation. Follow-up visits were performed on the 1st, 3rd, and 7th postoperative days, respectively. The primary outcome of this study was the I-FEED (Intake, Feeling nauseated, Emesis, Physical Exam, and Duration of symptoms) score on the third postoperative day (POD3). Secondary outcomes included time to postoperative first flatus, first feces, and first food intake (semi-liquid diet), I-FEED scores, visual analog scores (VAS) during coughing and at rest, times of patient-controlled intravenous analgesia (PCIA) effective presses, sufentanil dosage, number of remedial analgesia in the 24-hour postoperative period, and changes in inflammatory markers (TNF-α).

RESULTS

Compared with Group C, Group Z had a lower I-FEED score on POD1 (P < 0.05) and shorter time to first flatus and first food intake (P < 0.05); there were significant differences between the two groups in VAS scores during coughing and at rest on POD1, VAS score during coughing on POD3, times of PCIA effective presses and sufentanil dosage in the 24-hour postoperative period, and patient satisfaction (P < 0.05).

CONCLUSION

For patients with sleep disorders, the use of zolpidem to improve sleep the night before surgery is beneficial in partially improving postoperative gastrointestinal function, relieving postoperative pain, and increasing patient satisfaction.

TEST REGISTRATION

ChiCTR2300077566 November 13, 2023.

Exploring β-caryophyllene: a non-psychotropic cannabinoid's potential in mitigating cognitive impairment induced by sleep deprivation

Sleep deprivation or sleep loss, a prevalent issue in modern society, is linked to cognitive impairment, leading to heightened risks of errors and accidents. Chronic sleep deprivation affects various cognitive functions, including memory, attention, and decision-making, and is associated with an increased risk of neurodegenerative diseases, cardiovascular issues, and metabolic disorders. This review examines the potential of β-caryophyllene, a dietary non-psychotropic cannabinoid, and FDA-approved flavoring agent, as a therapeutic solution for sleep loss-induced cognitive impairment. It highlights β-caryophyllene's ability to mitigate key contributors to sleep loss-induced cognitive impairment, such as inflammation, oxidative stress, neuronal death, and reduced neuroplasticity, by modulating various signaling pathways, including TLR4/NF-κB/NLRP3, MAPK, Nrf2/HO-1, PI3K/Akt, and cAMP/PKA/CREB. As a naturally occurring, non-psychotropic compound with low toxicity, β-caryophyllene emerges as a promising candidate for further investigation. The review underscores the therapeutic potential of β-caryophyllene for sleep loss-induced cognitive impairment and provides mechanistic insights into its action on crucial pathways, suggesting that β-caryophyllene could be a valuable addition to strategies aimed at combating cognitive impairment and other health issues due to sleep loss.

Appraising the role of biotics and fermented foods in gut microbiota modulation and sleep regulation

Sleep disturbances are increasingly prevalent, significantly impacting physical and mental health. Recent research reveals a bidirectional relationship between gut microbiota and sleep, mediated through the microbiota-gut-brain axis. This review examines the role of gut microbiota in sleep physiology and explores how biotics, including probiotics, prebiotics, synbiotics, postbiotics, and fermented foods, can enhance sleep quality. Drawing from animal and human studies, we discuss neurobiological mechanisms by which biotics may influence sleep, including modulation of neurotransmitters, immune responses, and hormonal regulation. Key microbial metabolites, such as short-chain fatty acids, are highlighted for their role in supporting sleep-related neurochemical processes. Additionally, this review presents dietary strategies and food processing technologies, like fermentation, as innovative approaches for sleep enhancement. Although promising, the available research has limitations, including small sample sizes, variability in biotic strains and dosages, and reliance on subjective sleep assessments. This review underscores the need for standardized protocols, objective assessments such as polysomnography, and personalized biotic interventions. Emerging findings highlight the therapeutic potential of gut microbiota modulation for sleep improvement, though further large-scale human trials are essential to refine strain selection, dosage, and formulation. This interdisciplinary exploration seeks to advance food-based interventions and holistic strategies for managing sleep disorders and improving quality of life.

The involvement of amyloid-β in the central nervous system regulation underlying sleep deprivation-induced rapid ejaculation in rats

BACKGROUND

Although some studies suggest that sleep deprivation may affect ejaculation regulation, related research is limited, and the mechanisms remain unclear.

AIM

This study aimed to explore whether sleep deprivation influences ejaculation regulation through amyloid-beta and to investigate its potential mechanisms.

MATERIALS AND METHODS

Normal ejaculating rats were randomly distributed into three separate groups for the study, and treated with sleep deprivation combined with saline gavage, sleep deprivation combined with sodium butyrate gavage, and control with saline gavage. The levels of amyloid-beta and 5-HT1A receptors were assessed through Western blotting, PCR, and immunohistochemical techniques. The levels of interleukin-4 and serotonin (5-hydroxytryptamine) in the brain were determined by enzyme-linked immunosorbent assay.

RESULTS

The experiment showed that the rats in the sleep deprivation combined with saline gavage group rats had a significantly faster ejaculation compared to the control combined with saline gavage group rats. Meanwhile, sleep deprivation combined with saline gavage group had the highest levels of amyloid-beta oligomers in the brain tissue. Correlation results revealed that the levels of amyloid-beta oligomers in brain tissue were inversely related to ejaculation latency and positively associated with ejaculation frequency. Furthermore, we found that elevated levels of amyloid-beta oligomers in brain tissue led to upregulation of 5-HT1A receptor expression. Additionally, elevated levels of amyloid-beta oligomers in brain tissue were found to increase interleukin-4 levels, thereby reducing 5-hydroxytryptamine levels.

DISCUSSION

Sleep deprivation indeed accelerates ejaculation, and this acceleration is closely related to amyloid-beta. Sleep deprivation can increase amyloid-beta levels in brain tissue, mediating a decrease in 5-hydroxytryptamine levels and overexpression of 5-HT1A receptors, thereby accelerating ejaculation.

CONCLUSION

There is a significant correlation between elevated amyloid-beta levels in brain tissue because of sleep deprivation and accelerated ejaculation. This study's main findings offer insights into the development of acquired premature ejaculation linked to poor sleep and establish a theoretical framework for investigating potential treatments for this condition.

TMAO is involved in sleep deprivation-induced cognitive dysfunction through regulating astrocytic cholesterol metabolism via SREBP2

Sleep deprivation (SD) contributes to cognitive impairment. Astrocytic cholesterol biosynthesis is crucial for brain cholesterol homeostasis and cognitive function. However, the underlying mechanism of astrocytic cholesterol metabolism in SD-induced cognitive impairment has not been fully explored. Trimethylamine N-oxide (TMAO), a product of liver flavin-containing monooxygenase-3 (FMO3), has been shown to be increased in the urine of sleep-deprived humans and implicated with peripheral cholesterol metabolism. Nevertheless, how TMAO affects brain cholesterol metabolism remains unclear. In our study, increased FMO3 and brain TMAO levels were observed in the SD mice, and elevated levels of TMAO were confirmed to lead to SD-induced cognitive dysfunction. In addition, we found that the expression of sterol regulatory element-binding protein 2 (SREBP2) is decreased in the brain of SD mice, resulting in the reduction in brain cholesterol content, which in turn causes synaptic damage. Moreover, we demonstrated that TMAO inhibits the expression of SREBP2. In contrast, FMO3 inhibitor 3,3'-diindolylmethane (DIM) alleviates SD-induced cognitive impairment by targeting the liver-brain axis. In conclusion, our study revealed that the TMAO pathway is involved in memory impairment in SD mice through deregulating astrocytic cholesterol metabolism.

Dietary soy protein reverses obesity-induced liver steatosis and alters fecal microbial composition independent of isoflavone level

Introduction

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a major public health concern that is exacerbated by the obesity pandemic. Dietary interventions have the potential to alleviate obesity-associated MASLD through variable mechanisms, including optimizing the gut microbiota. Previously, we reported that soy protein concentrate (SPC) with low or high levels of isoflavone (LIF or HIF) protected young obese Zucker rats from developing liver steatosis. The current study was designed to test whether SPC-LIF and SPC-HIF diets would reverse liver steatosis and alter fecal microbial composition in adult obese Zucker rats with existing steatosis.

Methods

Six-week-old male obese Zucker rats (n = 26) were fed a casein control diet (CAS) for 8 weeks and 7 rats were randomly selected and sacrificed to confirm liver steatosis. The remaining rats were randomly assigned to receive CAS, SPC-LIF, or SPC-HIF diet (n = 6-7/group) for an additional 10 weeks.

Results

Compared to CAS diet, feeding SPC-LIF and SPC-HIF diets resulted in significantly lower liver weight, liver steatosis score, and liver microvesicular score (p < 0.05), but did not lead to difference in body weight, liver macrovesicular score, serum ALT, or serum AST. Isoflavone levels (e.g., LIF vs. HIF) did not affect any of these measurements except in the SPC-HIF group, which had an additional decrease in liver weight (p < 0.05) compared to the SPC-LIF group. The SPC-HIF group also had significantly higher levels of the aglycone forms of daidzein, genistein, and equol as well as the total levels of daidzein, genistein, and equol compared to SPC-LIF or CAS diet fed rats (p < 0.05). The distribution of microbial communities based on measures of beta diversity of both SPC-LIF and SPC-HIF groups were significantly different to that of the CAS group (p ≤ 0.005). Alpha-diversity did not differ between any of the groups.

Conclusion

Taken together, dietary soy protein can reverse liver steatosis in adult Zucker rats, and the reversal of steatosis is accompanied by alterations in gut microbial composition.

Continuous Theta Burst Stimulation Inhibits Oxidative Stress-Induced Inflammation and Autophagy in Hippocampal Neurons by Activating Glutathione Synthesis Pathway, Improving Cognitive Impairment in Sleep-Deprived Mice

Sleep deprivation (SD) has been reported to have a negative impact on cognitive function. Continuous theta burst stimulation (cTBS) shows certain effects in improving sleep and neurological diseases, and its molecular or cellular role in SD-induced cognition impairment still need further exploration. In this study, C57BL/6 mice were subjected to 48 h of SD and cTBS treatment, and cTBS treatment significantly improved SD-triggered impairment of spatial learning and memory abilities in mice. Additionally, cTBS reduced malondialdehyde levels, increased superoxide dismutase activities, and inhibited the production of inflammatory cytokines, alleviating oxidative stress and inflammation levels in hippocampal tissues of SD model mice. cTBS decreased LC3II/LC3I ratio, Beclin1 protein levels, and LC3B puncta intensity, and elevated p62 protein levels to suppress excessive autophagy in hippocampal tissues of SD-stimulated mice. Then, we proved that inhibiting oxidative stress alleviated inflammation, autophagy, and death of hippocampal neuron cells through an in vitro cellular model for oxidative stress, and cTBS treatment promoted the production of glutathione (GSH), the nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2) and the mRNA expression of GSH synthesis-related genes to enhance antioxidant capacity in hippocampal tissues of SD mice. An Nrf2 inhibitor ML385 or a GSH synthesis inhibitor BSO reversed the alleviating effects of cTBS treatment on oxidative stress-associated damage of hippocampal tissues and cognitive impairment in SD model mice. Altogether, our study demonstrated that cTBS mitigates oxidative stress-associated inflammation and autophagy through activating the Nrf2-mediated GSH synthesis pathway, improving cognitive impairment in SD mice.

Short-chain fatty acids ameliorate imiquimod-induced skin thickening and IL-17 levels and alter gut microbiota in mice: a metagenomic association analysis

Short-chain fatty acids (SCFAs) have been proposed to have anti-inflammatory effects and improve immune homeostasis. We aimed to examine the effects of SCFAs on skin phenotype, systemic inflammation, and gut microbiota in mice with psoriasis-like inflammation. Imiquimod (IMQ)-treated C57BL/6 mice served as the study model. We conducted a metagenomic association study of IMQ-mice treated with SCFAs or anti-IL-17 antibody using whole-genome shotgun sequencing. The associations among SCFA supplements, skin thickness, circulating inflammatory profiles, and fecal microbiota profiles were investigated. The microbiome study was performed using pipelines for phylogenetic analysis, functional gene analysis, and pathway analysis. In IMQ-treated mice, there were increases in skin thickness and splenic weight, as well as unique fecal microbial profiles. SCFAs ameliorated IMQ-induced skin thickening, splenic weight gain, and serum IL-17F levels, with results that were comparable with those receiving anti-IL-17 treatment. IMQ-treated mice receiving SCFAs had greater microbial diversity than mice treated with IMQ alone. SCFAs and anti-IL17 treatment were associated with alteration of gut microbiota, with increased prevalences of Oscillospiraceae and Lachnopiraceae and decreased prevalences of Muribaculaceae and Bacteroides, which have been predicted to be associated with increased glycan degradation, phenylalanine metabolism, and xylene degradation. SCFAs may mitigate IMQ-induced skin thickening and IL-17F levels and alter fecal microbiota profiles in IMQ-treated mice.

Gut microbiota and sleep: Interaction mechanisms and therapeutic prospects

Sleep is crucial for wellness, and emerging research reveals a profound connection to gut microbiota. This review explores the bidirectional relationship between gut microbiota and sleep, exploring the mechanisms involved and the therapeutic opportunities it presents. The gut-brain axis serves as a conduit for the crosstalk between gut microbiota and the central nervous system, with dysbiosis in the microbiota impairing sleep quality and vice versa. Diet, circadian rhythms, and immune modulation all play a part. Specific gut bacteria, like Lactobacillus and Bifidobacterium, enhance sleep through serotonin and gamma-aminobutyric acid production, exemplifying direct microbiome influence. Conversely, sleep deprivation reduces beneficial bacteria, exacerbating dysbiosis. Probiotics, prebiotics, postbiotics, and fecal transplants show therapeutic potential, backed by animal and human research, yet require further study on safety and long-term effects. Unraveling this intricate link paves the way for tailored sleep therapies, utilizing microbiome manipulation to improve sleep and health. Accelerated research is essential to fully tap into this promising field for sleep disorder management.

Distinct gut flora profile induced by postnatal trans-fat diet in gestationally bisphenol A-exposed rats

There has been much evidence showing the repercussions of prenatal bisphenol A (BPA) exposure with a postnatal high fat-diet (HFD) on offspring's health. However, the information on how the interaction between these two variables affects the gut microbiome is rather limited. Hence, we investigated the impact of a postnatal trans fat diet (TFD) on the gut microbiome of offspring exposed to BPA during the prenatal period in an animal model. Pregnant rats were divided into 5 mg/kg/day BPA, vehicle Tween80 (P80) or control (CTL) drinking water until delivery (N = 6 per group). Then, weaned male pups were further subdivided into three normal diet (ND) groups (CTLND, P80ND, and BPAND) and three TFD groups (CTLTFD, P80TFD, and BPATFD) (n = 6 per group). 180-250 g of faecal samples were collected on days 50 and 100 to assess the composition of the offspring's intestinal flora using next-generation sequencing. The alpha diversity indices of TFD offspring with and without BPA were markedly lower than their ND counterparts (p<0.001-p<0.05). The beta diversity, hierarchical cluster and network analyses of the offspring's microbiome demonstrated that the microbiome species of the TFD group with and without BPA were distinctly different compared to the ND group. Consistently, TFD and ND offspring pairings exhibited a higher number of significantly different species (p<0.0001-p<0.05) compared to those exposed to prenatal BPA exposure and different life stages comparisons, as shown by the multivariate parametric analysis DESeq2. Predictive functional profiling of the offspring's intestinal flora demonstrated altered expressions of genes involved in metabolic pathways. In summary, the gut flora composition of the rat offspring may be influenced by postnatal diet instead of prenatal exposure to BPA. Our data indicate the possibility of perturbed metabolic functions and epigenetic modifications, in offspring that consumed TFD, which may theoretically lead to metabolic diseases in middle or late adulthood. Further investigation is necessary to fully understand these implications.

Anorexia nervosa and bulimia nervosa: a Mendelian randomization study of gut microbiota

Background

Anorexia nervosa (AN) and bulimia nervosa (BN) poses a significant challenge to global public health. Despite extensive research, conclusive evidence regarding the association between gut microbes and the risk of AN and BN remains elusive. Mendelian randomization (MR) methods offer a promising avenue for elucidating potential causal relationships.

Materials and methods

Genome-wide association studies (GWAS) datasets of AN and BN were retrieved from the OpenGWAS database for analysis. Independent single nucleotide polymorphisms closely associated with 196 gut bacterial taxa from the MiBioGen consortium were identified as instrumental variables. MR analysis was conducted utilizing R software, with outlier exclusion performed using the MR-PRESSO method. Causal effect estimation was undertaken employing four methods, including Inverse variance weighted. Sensitivity analysis, heterogeneity analysis, horizontal multivariate analysis, and assessment of causal directionality were carried out to assess the robustness of the findings.

Results

A total of 196 bacterial taxa spanning six taxonomic levels were subjected to analysis. Nine taxa demonstrating potential causal relationships with AN were identified. Among these, five taxa, including Peptostreptococcaceae, were implicated as exerting a causal effect on AN risk, while four taxa, including Gammaproteobacteria, were associated with a reduced risk of AN. Similarly, nine taxa exhibiting potential causal relationships with BN were identified. Of these, six taxa, including Clostridiales, were identified as risk factors for increased BN risk, while three taxa, including Oxalobacteraceae, were deemed protective factors. Lachnospiraceae emerged as a common influence on both AN and BN, albeit with opposing effects. No evidence of heterogeneity or horizontal pleiotropy was detected for significant estimates.

Conclusion

Through MR analysis, we revealed the potential causal role of 18 intestinal bacterial taxa in AN and BN, including Lachnospiraceae. It provides new insights into the mechanistic basis and intervention targets of gut microbiota-mediated AN and BN.

Core fucosylation of maternal milk N-glycans imparts early-life immune tolerance through gut microbiota-dependent regulation in RORγt+ Treg cells

Milk glycans play key roles in shaping and maintaining a healthy infant gut microbiota. Core fucosylation catalyzed by fucosyltransferase (Fut8) is the major glycosylation pattern on human milk N-glycan, which was crucial for promoting the colonization and dominant growth of Bifidobacterium and Lactobacillus spp. in neonates. However, the influence of core-fucose in breast milk on the establishment of early-life immune tolerance remains poorly characterized. In this study, we found that the deficiency of core-fucose in the milk of maternal mice caused by Fut8 gene heterozygosity (Fut8+/-) resulted in poor immune tolerance towards the ovalbumin (OVA) challenge, accompanied by a reduced proportion of intestinal RORγt+ Treg cells and the abundance of Lactobacillus spp., especially L. reuteri and L. johnsonii, in their breast-fed neonates. The administration of the L. reuteri and L. johnsonii mixture to neonatal mice compromised the OVA-induced allergy and up-regulated the intestinal RORγt+ Treg cell proportions. However, Lactobacillus mixture supplementation did not alleviate allergic responses in RORγt+ Treg cell-deficient mice caused by Rorc gene heterozygosity (Rorc+/-) post OVA challenge, indicating that the intervention effects depend on the RORγt+ Treg cells. Interestingly, instead of L. reuteri and L. johnsonii, we found that the relative abundance of another Lactobacillus spp., L. murinus, in the gut of the offspring mice was significantly promoted by intervention, which showed enhancing effects on the proliferation of splenic and intestinal RORγt+ Treg cells in in vitro studies. The above results indicate that core fucosylation of breast milk N-glycans is beneficial for the establishment of RORγt+ Treg cell mediated early-life immune tolerance through the manipulation of symbiotic bacteria in mice.

Causal link between gut microbiome and schizophrenia: a Mendelian randomization study

OBJECTIVE

Some observational studies have shown that gut microbiome is significantly changed in patients with schizophrenia. We aim to identify the genetic causal link between gut microbiome and schizophrenia.

METHODS

A two-sample Mendelian randomization (MR) study was used to evaluate the causal link between gut microbiome and schizophrenia with 28 gut microbiome-associated genetic instrumental variants chosen from recent MR reports and the largest schizophrenia genome-wide association studies (8-Apr-22 release).

RESULTS

Inverse variance weighted method showed that genetically increased Bacteroidales_S24-7 (per SD) resulted in increased risk of schizophrenia (OR = 1.110, 95% CI: [1.012-1.217], P  = 0.027). Similarly, genetically increased Prevotellaceae promoted schizophrenia risk (OR = 1.124, 95% CI: [1.030-1.228], P  = 0.009). However, genetically increased Lachnospiraceae reduced schizophrenia risk (OR = 0.878, 95% CI: [0.785-0.983], P  = 0.023). In addition, schizophrenia risk was also suppressed by genetically increased Lactobacillaceae (OR = 0.878, 95% CI: [0.776-0.994], P  = 0.040) and Verrucomicrobiaceae (OR = 0.860, 95% CI: [0.749-0.987], P  = 0.032). Finally, we did not find any significant results in the causal association of other 23 gut microbiome with schizophrenia.

CONCLUSION

Our analysis suggests that genetically increased Bacteroidales_S24-7 and Prevotellaceae promotes schizophrenia risk, whereas genetically increased Lachnospiraceae, Lactobacillaceae, and Verrucomicrobiaceae reduces schizophrenia risk. Thus, regulation of the disturbed intestinal microbiota may represent a new therapeutic strategy for patients with schizophrenia.

Dietary vitamin A modifies the gut microbiota and intestinal tissue transcriptome, impacting intestinal permeability and the release of inflammatory factors, thereby influencing Aβ pathology

Background

Alzheimer's disease (AD) is an age-related neurodegenerative disorder with no effective interventions for curing or modifying its progression. However, emerging research suggests that vitamin A in the diet may play a role in both the prevention and treatment of AD, although the exact mechanisms are not fully understood.

Objectives

This study aims to investigate the dietary vitamin A modifies the gut microbiota and intestinal tissue transcriptome, impacting intestinal permeability and the release of inflammatory factors, thereby influencing Aβ pathology shedding light on its potential as a dietary intervention for AD prevention and treatment.

Methods

The APP/PS1-AD mouse model was employed and divided into three dietary groups: vitamin A-deficient (VAD), normal vitamin A (VAN), and vitamin A-supplemented (VAS) for a 12-week study. Neurobehavioral functions were assessed using the Morris Water Maze Test (MWM). Enzyme-linked immunosorbent assay (ELISA) was used to quantify levels of Diamine Oxidase (DAO), D-lactate, IL-6, IL-1β, and TNF-a cytokines. Serum vitamin A levels were analyzed via LC-MS/MS analysis. Immunohistochemical analysis and morphometry were performed to evaluate the deposition of Aβ in brain tissue. The gut microbiota of APP/PS1 mice was analyzed using 16S rRNA sequencing analysis. Additionally, transcriptomic analysis was conducted on intestinal tissue from APP/PS1 mice.

Results

No significant changes in food intake and body weight were observed among the groups. However, the VAD and VAS groups showed reduced food intake compared to the VAN group at various time points. In terms of cognitive function, the VAN group performed better in the Morris Water Maze Test, indicating superior learning and memory abilities. The VAD and VAS groups exhibited impaired performance, with the VAS group performing relatively better than the VAD group. Serum vitamin A concentrations differed significantly among the groups, with the VAS group having the highest concentration. Aβ levels were significantly higher in the VAD group compared to both the VAN and VAS groups. Microbial analysis revealed that the VAS and VAN groups had higher microbial diversity than the VAD group, with specific taxa characterizing each group. The VAN group was characterized by taxa such as Actinohacteriota and Desulfovibrionaceae, while the VAD group was characterized by Parabacteroides and Tannerellaceae. The VAS group showed similarities with both VAN and VAD groups, with taxa like Desulfobacterota and Desulfovibrionaceae being present. The VAD vs. VAS, VAD vs. VAN, and VAS vs. VAN comparisons identified 571, 313, and 243 differentially expressed genes, respectively, which associated with cellular and metabolic processes, and pathway analysis revealed enrichment in pathways related to chemical carcinogenesis, drug metabolism, glutathione metabolism, and immune-related processes. The VAD group exhibited higher levels of D-lactate, diamine oxidase, and inflammatory cytokines (TNF-a, IL-1β, IL-6) compared to the VAN and VAS groups.

Conclusion

Dietary vitamin A supplementation modulates the gut microbiota, intestinal permeability, inflammatory factors, and Aβ protein formation, offering insights into the pathogenesis of AD and potential therapeutic avenues for further exploration. This research highlights the intricate interplay between diet, gut microbiota, and neurodegenerative processes, emphasizing the importance of dietary interventions in managing AD-related pathologies.

Short-Term Ingestion of Essential Amino Acid Based Nutritional Supplements or Whey Protein Improves the Physical Function of Older Adults Independently of Gut Microbiome

SCOPE

Dietary proteins and essential amino acids (EAAs) are the major nutritional supplements that support the growth and activity of gut microbes contributing to the wellbeing of their host. This study hypothesizes that daily supplementation of the diet with either EAAs or whey protein for 12 weeks would improve the gut microbiome of older adults.

METHODS AND RESULTS

The stool samples are processed and subjected to Illumina-based 16S ribosomal ribonucleic acid (rRNA) gene amplicon sequencing. In both groups, the most abundant families are found in order of relative abundance included: Bacteroidaceae, Lachnospiraceae, Ruminococcaceae, Prevotellaceae, Rikenellaceae, Enterobacteriaceae, Oscillospiraceae, Tannerellaceae, and Akkermansiaceae, which indicate that these subjects are able to maintain a same healthy microbial diversity in their guts. A significant finding is a reduction of proinflammatory cytokine, interleukin-18 (IL-18) in the EAAs group. It also uses the standard 6-min walking test (6MWT) as a measure of cardiopulmonary fitness. At the end of the study, the subjects in the EAAs group perform significantly better in the 6MWT as compared to the whey group.

CONCLUSION

It seems plausible that the improved physical performance and reduced proinflammatory cytokine, IL-18 seen in the EAAs group, are independent of changes in gut microbiota.

Association between sleep-related phenotypes and gut microbiota: a two-sample bidirectional Mendelian randomization study

Background

An increasing body of evidence suggests a profound interrelation between the microbiome and sleep-related concerns. Nevertheless, current observational studies can merely establish their correlation, leaving causality unexplored.

Study objectives

To ascertain whether specific gut microbiota are causally linked to seven sleep-related characteristics and propose potential strategies for insomnia prevention.

Methods

The study employed an extensive dataset of gut microbiota genetic variations from the MiBioGen alliance, encompassing 18,340 individuals. Taxonomic classification was conducted, identifying 131 genera and 196 bacterial taxa for analysis. Sleep-related phenotype (SRP) data were sourced from the IEU OpenGWAS project, covering traits such as insomnia, chronotype, and snoring. Instrumental variables (IVs) were selected based on specific criteria, including locus-wide significance, linkage disequilibrium calculations, and allele frequency thresholds. Statistical methods were employed to explore causal relationships, including inverse variance weighted (IVW), MR-Egger, weighted median, and weighted Mode. Sensitivity analyses, pleiotropy assessments, and Bonferroni corrections ensured result validity. Reverse causality analysis and adherence to STROBE-MR guidelines were conducted to bolster the study's rigor.

Results

Bidirectional Mendelian randomization (MR) analysis reveals a causative interplay between selected gut microbiota and sleep-related phenotypes. Notably, outcomes from the rigorously Bonferroni-corrected examination illuminate profound correlations amid precise compositions of the intestinal microbiome and slumber-associated parameters. Elevated abundance within the taxonomic ranks of class Negativicutes and order Selenomonadales was markedly associated with heightened susceptibility to severe insomnia (OR = 1.03, 95% CI: 1.02-1.05, p = 0.0001). Conversely, the augmented representation of the phylum Lentisphaerae stands in concord with protracted sleep duration (OR = 1.02, 95% CI: 1.01-1.04, p = 0.0005). Furthermore, heightened exposure to the genus Senegalimassilia exhibits the potential to ameliorate the manifestation of snoring symptoms (OR = 0.98, 95% CI: 0.96-0.99, p = 0.0001).

Conclusion

This study has unveiled the causal relationship between gut microbiota and SRPs, bestowing significant latent value upon future endeavors in both foundational research and clinical therapy.

Hericium erinaceus Extract Exerts Beneficial Effects on Gut-Neuroinflammaging-Cognitive Axis in Elderly Mice

Ageing is a biological phenomenon that determines the impairment of cognitive performances, in particular, affecting memory. Inflammation and cellular senescence are known to be involved in the pathogenesis of cognitive decline. The gut microbiota-brain axis could exert a critical role in influencing brain homeostasis during ageing, modulating neuroinflammation, and possibly leading to inflammaging. Due to their anti-ageing properties, medicinal mushrooms can be utilised as a resource for developing pharmaceuticals and functional foods. Specifically, Hericium erinaceus (He), thanks to its bioactive metabolites, exerts numerous healthy beneficial effects, such as reinforcing the immune system, counteracting ageing, and improving cognitive performance. Our previous works demonstrated the capabilities of two months of He1 standardised extract oral supplementation in preventing cognitive decline in elderly frail mice. Herein, we showed that this treatment did not change the overall gut microbiome composition but significantly modified the relative abundance of genera specifically involved in cognition and inflammation. Parallelly, a significant decrease in crucial markers of inflammation and cellular senescence, i.e., CD45, GFAP, IL6, p62, and γH2AX, was demonstrated in the dentate gyrus and Cornus Ammonis hippocampal areas through immunohistochemical experiments. In summary, we suggested beneficial and anti-inflammatory properties of He1 in mouse hippocampus through the gut microbiome-brain axis modulation.