Anxiety, Depression, and the Microbiome: A Role for Gut Peptides

The impact of gut microbial short-chain fatty acids on colorectal cancer development and prevention

Cancer is a long-term illness that involves an imbalance in cellular and immune functions. It can be caused by a range of factors, including exposure to environmental carcinogens, poor diet, infections, and genetic alterations. Maintaining a healthy gut microbiome is crucial for overall health, and short-chain fatty acids (SCFAs) produced by gut microbiota play a vital role in this process. Recent research has established that alterations in the gut microbiome led to decreased production of SCFA's in lumen of the colon, which associated with changes in the intestinal epithelial barrier function, and immunity, are closely linked to colorectal cancer (CRC) development and its progression. SCFAs influence cancer progression by modifying epigenetic mechanisms such as DNA methylation, histone modifications, and non-coding RNA functions thereby affecting tumor initiation and metastasis. This suggests that restoring SCFA levels in colon through microbiota modulation could serve as an innovative strategy for CRC prevention and treatment. This review highlights the critical relationship between gut microbiota and CRC, emphasizing the potential of targeting SCFAs to enhance gut health and reduce CRC risk.

Evaluation of the two-way associations between mental disorders and menstrual irregularities: A Mendelian randomization study from both directions

OBJECTIVE

We aimed to assess the bidirectional relationship between mental disorders and menstrual irregularities using a two-sample Mendelian randomization (MR) approach.

METHODS

The analyses were conducted using a two-sample MR method. Analytical tools were derived from large-scale genome-wide association studies, including those on schizophrenia (SCZ, n = 127,906), bipolar disorder (BIP, n = 353,899), major depressive disorder (MDD, n = 674,452), anxiety and stress-related disorder (ASRD, n = 1,096,458), irregular menses (n = 196,550), excessive menstruation (n = 144,388), and dysmenorrhea (n = 114,540). Inverse variance weighting was used for the two-sample MR analyses, while sensitivity analyses were performed using MR-Egger, weighted median, and simple median methods.

RESULTS

MDD and ASRD were associated with an increased risk of irregular menses (P < 0.05); however, no reliable outcomes were found regarding the relationship between SCZ, BIP, and the three types of menstrual irregularities (P > 0.05). Furthermore, ASRD was also associated with an increased likelihood of excessive menstruation and dysmenorrhea (P < 0.05). However, the relationship between MDD and excessive menstruation was not statistically significant (P > 0.05). Dysmenorrhea was associated with an increased risk of MDD and ASRD (P < 0.05).

CONCLUSION

This study provides strong evidence supporting the associations between ASRD and the three types of menstrual irregularities, as well as between MDD and irregular menses and dysmenorrhea.

Ghrelin in Depression: A Promising Therapeutic Target

Depression is a widespread disease affecting over 300 million individuals of various ethnicities and socioeconomic backgrounds globally. It frequently strikes early in life and becomes a chronic or recurring lifelong illness. Out of the various hypotheses for the pathophysiology of depression, the gut-brain axis and stress hypothesis are the ones that need to be researched, as psychological stress impairs one or more pathways of the brain-gut axis and is likely to cause brain-gut axis dysfunction and depression. A dysfunctional reciprocal gut-brain relationship may contribute to many diseases, including inflammatory disorders, abnormal stress responses, impaired behavior, and metabolic changes. The hormone ghrelin is a topic of interest concerning the gut-brain axis as it interacts with the gut-brain axis indirectly via the central nervous system or via crossing the blood-brain barrier. Ghrelin release is also affected by the gut microbes, which has also been discussed in the review. This review elaborates on Ghrelin's role in depression and its effect on various aspects like neurogenesis, HPA axis, and neuroinflammation. Furthermore, this review focuses on ghrelin as a potential target for alleviation of depressive symptoms.

The Role and Mechanisms of Probiotic Supplementation on Depressive Symptoms: A Narrative Review

PURPOSE OF REVIEW

The microbiota-gut-brain-axis (MGBA) plays a role in the aetiology of mental disorders. Depression, a leading cause of disability worldwide, may be improved by probiotics. The aim of this narrative review is to investigate and synthesize the current evidence linking probiotic food supplementation with depressive symptomology.

RECENT FINDINGS

The gut and the brain communicate and interact via the MGBA through inflammation and the immune system, short chain fatty acid production, neuronal innervation and activation as well as endocrine and neurotransmitter modulation. Dysregulation of gut-brain pathways are caused by gut dysbiosis and implicated in the onset, persistence and exacerbation of depression related symptoms. Modulation of the gut microbiota via administration of probiotics has shown to reduce depressive symptom severity with Bifidobacterium and Lactobacillus strains being the most reported. Probiotics may produce greater benefits in mild depression rather than in chronic, treatment resistant depression. Probiotic supplementation is a promising and safe approach for the prevention of severe depressive disorders in high-risk individuals such as people with subthreshold depression. However, the mechanistic pathways of the MGBA require further investigation and additional human clinical trials are necessary to evaluate the role of probiotics on depression.

Granola consumption with multiple prebiotics in Japanese participants increases Bifidobacterium abundance and improves stress and subjective sleepiness

Background

Sleep is essential for physical and mental health. However, stress-related sleep disorders are common in Japan, and the gut-brain axis may play a role in sleep and stress management. This study investigated whether the consumption of granola containing multiple prebiotic ingredients could alleviate stress and improve insomnia in adults with stress-related sleep problems, regardless of individual differences in the gut microbiota. Additionally, we aimed to investigate the relationship between changes in gut microbiota and the observed improvements.

Method

A single-arm uncontrolled trial was conducted with 27 adults with high stress levels and sleep disturbance. The participants consumed 50 g of prebiotics-containing granola daily for 8 weeks. Subjective sleep quality was assessed using the Athens Insomnia Scale, Epworth Sleep Scale, and Oguri-Shirakawa-Azumi Sleep Inventory-Middle-aged and Aged version (OSA-MA). Stress levels were assessed by administering the Brief Job Stress Questionnaire and Profile of Mood States 2nd edition (POMS2). Gut microbiota composition was analyzed using 16S rDNA sequencing.

Results

After 8 weeks, subjective insomnia scores and sleep onset and maintenance improved significantly, whereas the stress and mood disturbance scores decreased significantly. Gut microbiota analysis showed that the relative abundance of Bifidobacterium increased, whereas that of Bacteroides decreased. Correlation analysis suggested a significant association between increased Bifidobacterium level and reduced stress (r = -0.39, p = 0.0035) and insomnia levels (r = -0.3, p = 0.026).

Conclusion

Prebiotics-containing granola improved subjective sleep quality and reduced stress in adults with stress-related sleep disturbances, which may be attributed to alterations in gut microbiota, particularly the increase in Bifidobacterium abundance.

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.

Association of escitalopram-induced shifts in gut microbiota and sphingolipid metabolism with depression-like behavior in wistar-kyoto rats

The microbiota-gut-brain axis plays a pivotal role in neuropsychiatric disorders, particularly in depression. Escitalopram (ESC) is a first-line antidepressant, however, its regulatory mechanisms on the microbiota-gut-brain axis in the treatment of depression remain unclear. The antidepressant effects of ESC were evaluated using the forced swim test in Wistar-Kyoto (WKY) rats, while damage in the gut and brain regions was assessed through H&E staining and immunohistochemistry. The therapeutic mechanisms in WKY rats with depression-like behavior were investigated through 16S rRNA sequencing of the gut microbiota, serum untargeted metabolomics, and hippocampal proteomics. Results indicated that ESC intervention improved depressive-like behaviors, as evidenced by increased swimming times in WKY rats, and also restored intestinal permeability and brain tissue integrity. Significant changes in the gut microbiota composition, particularly an increase in Bacteroides barnesiae, as well as increases in serum sphingolipid metabolites (Sphinganine 1-phosphate, Sphingosine, and Sphingosine-1-phosphate) and hippocampal proteins (Sptlc1, Enpp5, Enpp2), were strongly correlated. These robust correlations suggest that ESC may exert its antidepressant effects by modulating sphingolipid metabolism through the influence of gut microbiota. Accordingly, this research elucidates novel mechanisms underlying the antidepressant efficacy of ESC and highlights the pivotal importance of the microbiota-gut-brain axis in mediating these effects.

Edinburgh postpartum depression scores are associated with vaginal and gut microbiota in pregnancy

BACKGROUND

Prenatal and postpartum depression may be influenced by the composition of host associated microbiomes. As such, the objective of this study was to elucidate the relationship between the human gut or vaginal microbiomes in pregnancy with prenatal or postpartum depression.

METHODS

140 female participants were recruited at their first prenatal visit and completed the Edinburgh Postnatal Depression Scale (EPDS) to screen for depression and anxiety, in addition the EPDS was completed one month postpartum. Vaginal and stool biospecimens were collected in the third trimester, analyzed using 16S rRNA gene sequencing, and assessed for alpha and beta diversity. Individual taxa differences and clustering using the k-medoids algorithm enabled community state type classification.

RESULTS

Participants with higher postpartum EPDS scores had higher species richness and lower abundance of L. crispatus in the vaginal microbiota compared to those with lower EPDS scores. Participants with a higher prenatal EPDS score had lower species richness of the gut microbiome. Participants with a vaginal community state type dominated by L. iners had the highest mean prenatal EPDS scores, whereas postpartum EPDS scores were similar regardless of prenatal vaginal state type.

LIMITATIONS

Our small sample size and participant's self-report bias limits generalizability of results.

CONCLUSIONS

Depression in the prenatal and postpartum period is associated with the composition and diversity of the gut and vaginal microbiomes in the third trimester of pregnancy. These results provide a foundational understanding of the microbial relationships between maternal health and depression for identifying potential therapeutic treatments.

Porphyromonas gingivalis: a potential trigger of neurodegenerative disease

Porphyromonas gingivalis (P. gingivalis) is a gram-negative bacterium and the main causative agent of periodontitis, a disease closely associated with the development of periodontal disease. The progression of periodontitis, a chronic infectious disease, is intricately linked to the inflammatory immune response. Inflammatory cytokines act on periodontal tissues via immunomodulation, resulting in the destruction of the periodontal tissue. Recent studies have established connections between periodontitis and various systemic diseases, including cardiovascular diseases, tumors, and neurodegenerative diseases. Neurodegenerative diseases are neurological disorders caused by immune system dysfunction, including Alzheimer's and Parkinson's diseases. One of the main characteristics of neurodegenerative diseases is an impaired inflammatory response, which mediates neuroinflammation through microglial activation. Some studies have shown an association between periodontitis and neurodegenerative diseases, with P. gingivalis as the primary culprit. P. gingivalis can cross the blood-brain barrier (BBB) or mediate neuroinflammation and injury through a variety of pathways, including the gut-brain axis, thereby affecting neuronal growth and survival and participating in the onset and progression of neurodegenerative diseases. However, comprehensive and systematic summaries of studies on the infectious origin of neurodegenerative diseases are lacking. This article reviews and summarizes the relationship between P. gingivalis and neurodegenerative diseases and its possible regulatory mechanisms. This review offers new perspectives into the understanding of neurodegenerative disease development and highlights innovative approaches for investigating and developing tailored medications for treating neurodegenerative conditions, particularly from the viewpoint of their association with P. gingivalis.

Advancements in the Pathogenesis, Diagnosis, and Therapeutic Implications of Intestinal Bacteria

Intestinal bacteria form one of the most complex microbial communities in the human body, playing a crucial role in maintaining host health and contributing to the development of various diseases. Here, we provide a comprehensive overview of the composition and function of intestinal bacteria, the factors affecting their homeostasis, and their association and mechanisms with a range of diseases (e.g., inflammatory bowel diseases, colorectal cancer, metabolic diseases). Additionally, their advanced potential in disease diagnosis and treatment is highlighted. Therapies, such as chemotherapy, radiotherapy, and immunotherapy, are significantly impacted by intestinal bacteria, with research indicating that bacteria can enhance chemoimmunotherapy efficiency by affecting T cell recruitment and immune cell infiltration. Fecal microbiota transplantation has emerged as a promising option for treating recurrent Clostridium difficile infections and certain metabolic and neurological disorders. Gut bacteria-related serum metabolites serve as non-invasive indicators for diagnosing CRC, while fecal immunochemical tests offer promising applications in CRC screening. Future research is needed to better understand the causal relationships between intestinal bacteria and diseases, develop more precise diagnostic tools, and evaluate the effectiveness and safety of microbiome-targeted therapies in clinical treatment. This study provides deeper insights into the role of intestinal bacteria in human health and disease, providing a scientific basis for innovative therapeutic strategies that have the potential to transform the landscape of healthcare.

Microbiota-Gut-Brain Axis: Mass-Spectrometry-Based Metabolomics in the Study of Microbiome Mediators-Stress Relationship

The microbiota-gut-brain axis is a complex bidirectional communication system that involves multiple interactions between intestinal functions and the emotional and cognitive centers of the brain. These interactions are mediated by molecules (metabolites) produced in both areas, which are considered mediators. To shed light on this complex mechanism, which is still largely unknown, a reliable characterization of the mediators is essential. Here, we review the most studied metabolites in the microbiota-gut-brain axis, the metabolic pathways in which they are involved, and their functions. This review focuses mainly on the use of mass spectrometry for their determination, reporting on the latest analytical methods, their limitations, and future perspectives. The analytical strategy for the qualitative-quantitative characterization of mediators must be reliable in order to elucidate the molecular mechanisms underlying the influence of the above-mentioned axis on stress resilience or vulnerability.

Mechanism of adolescent depression and Non-Suicidal Self-Injury: Interaction between interpersonal relationship and the OXTR gene

BACKGROUND

Based on ecosystem theory and genetic and environmental research paradigms, the current research explored the influence mechanism of interpersonal relationship and OXTR gene rs1042778, rs2254298 and rs53576 polymorphisms on adolescent depression and NSSI.

METHOD

The main study investigation explored the effect of the interaction between interpersonal relationship and OXTR gene on adolescent depression and Non-Suicidal Self-Injury (NSSI). Concurrently, a supplementary examination investigated oxytocin's physiological impact on the social-emotional behaviors of mice subjected to post-weaning social isolation.

RESULTS

OXTR gene rs2254298 and rs53576 moderated the influence of interpersonal relationship on adolescent depression, and rs2254298 also moderated the influence of interpersonal relationship on adolescent NSSI. PWSI reduced the mice's emotional social ability and affected the expression and transcription of OXT and OXTR mRNA, which could be reversed after an appropriate dose of oxytocin treatment.

CONCLUSION

Interaction between interpersonal relationship and the OXTR gene affects adolescent depression and NSSI. The OXTR gene heterozygous genotype individuals were more sensitive to environmental stimuli, supporting the differential susceptibility model.

Estradiol metabolism by gut microbiota in women's depression pathogenesis: inspiration from nature

The recurrence and treatment resistance of depression remain significant issues, primarily due to an inadequate understanding of its pathogenesis. Recent scientific evidence indicates that gut microbiota influence estradiol metabolism and are associated with the development of depression in nonpremenopausal women. Integrating existing studies on the regulation of estradiol metabolism by microorganisms in nature and the relevance of its degradation products to depression, recent scientific explorations have further elucidated the key mechanisms by which gut microbiota catabolize estradiol through specific metabolic pathways. These emerging scientific findings suggest that the unique metabolic effects of gut microbiota on estradiol may be one of the central drivers in the onset and course of depression in non-menopausal women.

A disturbed communication between hypothalamic-pituitary-ovary axis and gut microbiota in female infertility: is diet to blame?

Female infertility is a multifactorial condition influenced by various genetic, environmental, and lifestyle factors. Recent research has investigated the significant impact of gut microbiome dysbiosis on systemic inflammation, metabolic dysfunction, and hormonal imbalances, which can potentially impair fertility. The gut-brain axis, a bidirectional communication system between the gut and the brain, also plays a significant role in regulating reproductive functions. Emerging evidence suggests that the gut microbiome can influence brain functions and behavior, further emphasizing the importance of the microbiota-gut-brain axis in reproduction. Given their role as a major modulator of the gut microbiome, diet and dietary factors, including dietary patterns and nutrient intake, have been implicated in the development and management of female infertility. Hence, this review aims to highlight the impact of dietary patterns, such as the Western diet (WD) and Mediterranean diet (MD), and to decipher their modulatory action on the microbiota-gut-brain axis in infertile women. By contrasting the detrimental effects of WD with the therapeutic potential of MD, we emphasize the pivotal role of a balanced diet rich in nutrients in promoting a healthy gut microbiome. These insights underscore the potential of targeted dietary interventions and lifestyle modifications as promising strategies to enhance reproductive outcomes in subfertile women.

New perspectives on microbiome-dependent gut-brain pathways for the treatment of depression with gastrointestinal symptoms: from bench to bedside

Patients with depression are more likely to have chronic gastrointestinal (GI) symptoms than the general population, but such symptoms are considered only somatic symptoms of depression and lack special attention. There is a chronic lack of appropriate diagnosis and effective treatment for patients with depression accompanied by GI symptoms, and studying the association between depression and GI disorders (GIDs) is extremely important for clinical management. There is growing evidence that depression is closely related to the microbiota present in the GI tract, and the microbiota-gut-brain axis (MGBA) is creating a new perspective on the association between depression and GIDs. Identifying and treating GIDs would provide a key opportunity to prevent episodes of depression and may also improve the outcome of refractory depression. Current studies on depression and the microbially related gut-brain axis (GBA) lack a focus on GI function. In this review, we combine preclinical and clinical evidence to summarize the roles of the microbially regulated GBA in emotions and GI function, and summarize potential therapeutic strategies to provide a reference for the study of the pathomechanism and treatment of depression in combination with GI symptoms.

Relationship Between Depression and Epigallocatechin Gallate from the Perspective of Gut Microbiota: A Systematic Review

Depression, a serious mental illness, is characterized by high risk, high incidence, persistence, and tendency to relapse, posing a significant burden on global health. The connection between depression and gut microbiota is an emerging field of study in psychiatry and neuroscience. Understanding the gut-brain axis is pivotal for understanding the pathogenesis and treatment of depression. Gut microbes influence depression-like behaviors by impacting the hypothalamic-pituitary-adrenal axis (HPA), monoamine neurotransmitters, immune responses, cell signaling, and metabolic pathways. Tea, widely used in clinical practice to improve neuropsychiatric disorders, contains Epigallocatechin gallate (EGCG), a major ingredient of green tea, which effectively regulates intestinal flora. This review examined the risks and causes of depression, the complications associated with intestinal flora, their role in the development and treatment of depression, and how EGCG may alleviate depression through interactions with gut microbiota and other mechanisms.

Precision Psychobiotics for Gut-Brain Axis Health: Advancing the Discovery Pipelines to Deliver Mechanistic Pathways and Proven Health Efficacy

Advancing microbiome-gut-brain axis science requires systematic, rational and translational approaches to bridge the critical knowledge gaps currently preventing full exploitation of the gut microbiome as a tractable therapeutic target for gastrointestinal, mental and brain health. Current research is still marked by many open questions that undermine widespread application to humans. For example, the lack of mechanistic understanding of probiotic effects means it remains unclear why even apparently closely related strains exhibit different effects in vivo. For the therapeutic application of live microbial psychobiotics, consensus on their application as adjunct treatments to conventional neuromodulators, use in unmedicated populations or in at-risk cohorts with sub-clinical symptomatology is warranted. This missing information on both sides of the therapeutic equation when treating central nervous system (CNS) conditions makes psychobiotic research challenging, especially when compared to other pharmaceutical or functional food approaches. Expediting the transition from positive preclinical data to proven benefits in humans includes interpreting the promises and pitfalls of animal behavioural assays, as well as navigating mechanism-informed decision making to select the right microbe(s) for the job. In this review, we consider how these decisions can be supported in light of information accrued from a range of clinical studies across healthy, at-risk and pathological study populations, where specific strains have been evaluated in the context of gastrointestinal physiology, brain function and behaviour. Examples of successful, partial and unsuccessful translation from bench to bedside are considered. We also discuss the developments in in silico analyses that have enhanced our understanding of the gut microbiome and that have moved research towards pinpointing the host-microbe interactions most important for optimal gut-brain axis function. Combining this information with knowledge from functional assays across in vitro and ex vivo domains and incorporating model organisms can prime the discovery pipelines with the most promising and rationally selected psychobiotic candidates.

Ghrelin, Neuroinflammation, Oxidative Stress, and Mood Disorders: What Are the Connections?

Ghrelin is a gut peptide hormone associated with feeding behavior and energy homeostasis. Acylated ghrelin binds to the growth hormone secretagogue receptor 1a subtype (GHS-R1a) in the hippocampus, leading to GH release from the anterior pituitary. However, in recent years, ghrelin and its receptor have also been implicated in other processes, including the regulation of cardiomyocyte function, muscle trophism, and bone metabolism. Moreover, GHS-R1a is distributed throughout the brain and is expressed in brain areas that regulate the stress response and emotional behavior. Consistently, a growing body of evidence supports the role of ghrelin in regulating stress response and mood. Stress has consistently been shown to increase ghrelin levels, and despite some inconsistencies, both human and rodent studies suggested antidepressant effects of ghrelin. Nevertheless, the precise mechanism by which ghrelin influences stress response and mood remains largely unknown. Intriguingly, ghrelin and GHS-R1a were consistently reported to exert anti-inflammatory, antioxidant, and neurotrophic effects both in vivo and in vitro, although this has never been directly assessed in relation to psychopathology. In the present review we will discuss available literature linking ghrelin with the stress response and depressive-like behavior in animal models as well as evidence describing the interplay between ghrelin and neuroinflammation/oxidative stress. Although further studies are required to understand the mechanisms involved in the action of ghrelin on mood, we hypothesize that the antiinflammatory and anti-oxidative properties of ghrelin may give a key contribution.

Human gut microbiome, diet, and mental disorders

Diet is one of the most important external factor shaping the composition and metabolic activities of the gut microbiome. The gut microbiome plays a crucial role in host health, including immune system development, nutrients metabolism, and the synthesis of bioactive molecules. In addition, the gut microbiome has been described as critical for the development of several mental disorders. Nutritional psychiatry is an emerging field of research that may provide a link between diet, microbial function, and brain health. In this study, we have reviewed the influence of different diet types, such as Western, Mediterranean, vegetarian, and ketogenic, on the gut microbiota composition and function, and their implication in various neuropsychiatric and psychological disorders.

Investigating the bacterial profiles of Lactobacillus, Bifidobacterium, Actinobacteria, Fusobacterium, Firmicutes, and Bacteroides in stool samples from patients with severe depression and healthy individuals

Depression is a multifaceted mental health disorder with complex etiology and significant global burden. Recent research indicates that the gut microbiota plays a role in the pathophysiology of depression, highlighting the potential role of specific bacterial species in influencing mood and cognitive function. In this study, we aimed to investigate the presence, copy numbers, and Ct values of selected bacterial species in stool samples from depressed patients (n=50) compared to control subjects (n=50). Our findings revealed significant differences in the abundance of Fusobacterium spp., Bifidobacterium spp., Lactobacillus spp., Bacteroidetes phylum, Firmicutes phylum, and Actinobacteria spp. between the two groups. Dysregulation of the gut microbiota, characterized by decreased presence of beneficial bacteria (e.g., Bifidobacterium spp., Lactobacillus spp.) and altered abundance of potentially pathogenic bacteria (e.g., Fusobacterium spp.), may contribute to the development or exacerbation of depression. These findings support the emerging concept of the gut-brain axis and its role in mental health. However, further research is needed to better understand the underlying mechanisms and explore the therapeutic potential of microbiota-targeted interventions for depression. Understanding the intricate interplay between the gut microbiota and depression could pave the way for novel treatment strategies and personalized approaches in mental health care.

Cesarean delivery and its determining factors: A hospital-based study in Jashore District, Bangladesh

Background

The rising prevalence of cesarean deliveries (CD) is a major public health problem worldwide, especially in Bangladesh. This study aims to investigate the prevalence and factors associated with cesarean deliveries in the Jashore district of Bangladesh.

Study design

This cross-sectional study, conducted from December 2022 to February 2023 in Jashore district, Bangladesh, involved face-to-face interviews with 662 mothers during hospital visits.

Methods

A pretested, structured, and validated questionnaire was employed to gather information on socioeconomic characteristics, obstetric history, maternal healthcare utilization, and factors influencing the choice of delivery method. Multinomial logistic regression models were employed to assess and predict determining factors influencing cesarean delivery.

Results

The study revealed a high cesarean delivery (CD) prevalence of 70.5 %, exceeding the WHO-recommended threshold. Key socioeconomic factors associated with increased CD rates included rural residence, younger maternal age (15-20 years), nuclear family structure, and husbands in business. Additionally, private hospital deliveries, a history of previous CD, maternal self-preference, and doctor's influence were significant predictors of CD. The majority of participants believed CD enhances maternal safety (74.6 %) and alleviates pain (74.8 %).

Conclusion

The high rate of cesarean deliveries in Jashore highlights the need for public health interventions that improve access to quality maternal care and promote evidence-based decision-making. Reducing unnecessary cesarean procedures, particularly in private hospitals, and enhancing patient education can significantly improve maternal and neonatal health outcomes.

Perturbed microbial ecology in neuromyelitis optica spectrum disorder: Evidence from the gut microbiome and fecal metabolome

BACKGROUND

Neuromyelitis optica spectrum disorder (NMOSD) is a central nervous system inflammatory demyelinating immune-mediated ailment, which is influenced by genetic, epigenetic, and environmental elements. The escalating incidence of NMOSD in recent years implies alterations in environmental risk factors. Recent research has established a correlation between gut microbiomes and the development of NMOSD.

METHODS

Metagenomic shotgun sequencing and gas chromatography-mass spectrometry (GC-MS) were employed to assess alterations of the structure and function in the fecal microbiome, as well as levels of short-chain fatty acids (SCFAs) in fecal and blood samples, among individuals with neuromyelitis optica spectrum disorder (NMOSD) during the acute phase (n = 25), the remission phase (n = 11), and a group of healthy controls (HCs) (n = 24). We further explored the correlation between gut microbiota and the pathogenesis of NMOSD through fecal microbiota transplantation (FMT). The gut microbiome from human donors diagnosed with NMOSD or HCs was transplanted into germ-free mice, followed by an analysis of the alterations in the structure and functionality of the transplanted mice's gut microbiome. Additionally, the impact of microbiome transfer on the immunity and spinal cord of germ-free mice was assessed through various techniques, including ELISA, flow cytometry, western blot, histopathology, and transcriptome sequencing.

RESULTS

(1) At the taxonomic levels of genus and species, there were significant differences in the α-diversity of the microbiome between HCs and NMOSD patients in the acute phase, with NMOSD patients having higher species diversity. (2) In the acute phase, the gut microbiota of NMOSD patients was characterized by Ruminococcaceae_unclassified, Campylobacter, Parabacteroides, Lactobacillus, Akkermansia, Streptococcus oralis, Clostridium leptum, Clostridium asparagiforme, Firmicutes bacterium CAG 238, and Lactobacillus fermentum. (3) The relative abundances of Coprobacter, Turicimonas, Gemmiger, Enterobacter, Roseburia sp.CAG 471, Veillonella tobetsuensis, Proteobacteria bacterium CAG 139, Ruminococcus bicirculans, Lactococcus lactis, Flavonifractor plautii, and Streptococcus cristatus were notably lower in patients experiencing remission compared to NMOSD patients in the acute phase, On the other hand, the relative abundances of Flavonifractor (P = 0.049) and Clostridium aldenense (P = 0.049) were significantly higher. Following medication, the gut microbiome distribution in NMOSD patients during remission closely resembled that of healthy controls (HCs). (4) Compared with HCs, acetate levels in the feces of patients with NMOSD in the acute phase were significantly lower. (5) In addition, we transplanted feces from NMOSD patients into germ-free mice and revealed a significant increase in the levels of IL-6, IL-17A, and IL-23 in the blood of mice belonging to the NMOSD fecal transplantation (NFMT) group. Additionally, the IL-10 level exhibited a significant reduction. Moreover, the proportion of Th17 cells displayed a significant increase, while the proportion of Treg cells exhibited a significant decrease in the spleens of NFMT mice.

CONCLUSION

Patients in the acute phase of neuromyelitis optica spectrum disorder (NMOSD) exhibited imbalances in their gut microbiota and a deficiency in short-chain fatty acids (SCFAs). Following drug treatment, the composition of intestinal microbes in NMOSD patients during the remission phase closely resembled that of the healthy control population. The FMT experiment provided evidence of the significant association between intestinal flora and the pathogenesis of NMOSD. Consequently, investigating gut microbiota and identifying novel microbial markers hold promise for the diagnosis and treatment of NMOSD patients.

Beyond the Brain: Attention Deficit/Hyperactivity Disorder and the Gut-Brain Axis

Attention-deficit/hyperactivity disorder (ADHD) is a complex neurodevelopmental condition, predominantly affecting children, characterized by inattention, hyperactivity, and impulsivity. A growing body of evidence has highlighted the potential influence of the gut microbiota on the onset and presentation of ADHD symptoms. The gut microbiota, a diverse microbial ecosystem residing within the gastrointestinal tract, exerts multiple effects on systemic physiology, including immune modulation, metabolic regulation, and neuronal signalling. The bidirectional gut-brain axis serves as a conduit for communication between gut microbes and the central nervous system, implicating its disruption in neurodevelopmental disorders such as ADHD. This comprehensive literature review aims to shed light on how alterations in the gut microbiota influence the development and manifestation of ADHD symptoms. Examining potential mechanisms involving gut microbial metabolites and their impact on neurotransmitter modulation, neuro-endocrine signalling and neuroinflammation, we dissect the intricate interplay shaping ADHD pathology. Insights into these complex interactions hold promise for personalized therapeutic interventions aimed at modulating the gut microbiota to ameliorate ADHD symptoms. Discussions encompass dietary interventions, faecal microbiota-targeted therapies, and emerging probiotic approaches, underscoring their potential as adjunctive or alternative strategies in managing ADHD. Further research elucidating the precise mechanisms driving these interactions may pave the way for targeted and personalized interventions for individuals grappling with ADHD.

Impact of the gut microbiota-Th17 cell axis on inflammatory depression

Depression is a serious cognitive disorder that results in significant and pervasive deficits in social behavior. These deficits can be traced back to the intricate interplay between social, psychological, and biological factors. Inflammatory depression, a treatment-resistant or non-responsive subtype of depression, may be related to the interaction between the gut microbiota and interleukin-17-producing CD4+ T cells (Th17 cells). The heterogeneity, plasticity, and effector role of Th17 cells in depression may be influenced by microbiota factors. Commensals-elicited homeostatic Th17 cells preserve the morphological and functional integrity of the intestinal barrier. In addition to pathogen-elicited inflammatory Th17 cells, commensal-elicited homeostatic Th17 cells can become conditionally pathogenic and contribute to the development of inflammatory depression. This review delves into the possible involvement of Th17 cells in inflammatory depression and examines the interplay between gut microbiota and either homeostatic or inflammatory Th17 cells.

Microbiome Shifts and Their Impact on Gut Physiology in Irritable Bowel Syndrome

Irritable bowel syndrome (IBS) is one of the most prevalent functional gastrointestinal disorders characterized by recurrent abdominal pain and altered bowel habits. The exact pathophysiological mechanisms for IBS development are not completely understood. Several factors, including genetic predisposition, environmental and psychological influences, low-grade inflammation, alterations in gastrointestinal motility, and dietary habits, have been implicated in the pathophysiology of the disorder. Additionally, emerging evidence highlights the role of gut microbiota in the pathophysiology of IBS. This review aims to thoroughly investigate how alterations in the gut microbiota impact physiological functions such as the brain-gut axis, immune system activation, mucosal inflammation, gut permeability, and intestinal motility. Our research focuses on the dynamic "microbiome shifts", emphasizing the enrichment or depletion of specific bacterial taxa in IBS and their profound impact on disease progression and pathology. The data indicated that specific bacterial populations are implicated in IBS, including reductions in beneficial species such as Lactobacillus and Bifidobacterium, along with increases in potentially harmful bacteria like Firmicutes and Proteobacteria. Emphasis is placed on the imperative need for further research to delineate the role of specific microbiome alterations and their potential as therapeutic targets, providing new insights into personalized treatments for IBS.

Apple Polyphenol Extracts Attenuated Depressive-Like Behaviors of High-Sucrose Diet Feeding Mice by Farnesoid X Receptor-Mediated Modulation of Bile Acid Circulation within the Liver-Gut-Brain Axis

Although the association between high-sugar diets and depression has been verified, few studies have explored the antidepressant mechanisms of apple polyphenol extracts (APE). Therefore, fifty-four C57BL/6 male mice aged 5 weeks were randomly assigned into five groups: the control group with the standard diet (CON), the constant high-sucrose diet group (HSD), the "2 + 5" alternate diet group (A-HSD), and the 500 mg/(kg·bw) APE treatment for the HSD group (APE) and the A-HSD group (A-APE), respectively. The data of hypothalamic-pituitary-adrenal (HPA) axis function and behavioral experiments confirmed the success in the establishment of depression-like mouse models in both HSD and A-HSD groups, which were significantly alleviated after APE treatment. Meanwhile, APE reduced serum levels of corticosterone and adrenocorticotrophic hormone, alleviated histopathological damage of the liver, colon, and brain, respectively, elevated the protein expressions of Occludin, ZO-1, and MUC-2, and decreased Firmicutes/Bacteroidota ratio and Dubosiella abundance with the increased microbiota of Tannerellaceae_unclassified, Muribaculum, and Lachnospiraceae_unclassified. Moreover, APE treatment reduced Farnesoid X receptor (FXR) protein levels along with the increased expressions of CYP7A1 and TGR5, lowered the contents of serum and fecal total bile acids, and modulated fecal BA compositions, particularly glycocholic acid (GCA) and isolithocholic acid (ILCA). Thus, both the constant and alternate high-sucrose diets successfully induced depression-like behaviors in mice, and APE might be a potential nutraceutical to attenuate high-sucrose diet-induced depression by regulating BAs circulation within the liver-gut-brain axis mediated by FXR.

Sex-specific gene expression differences in the prefrontal cortex of major depressive disorder individuals

Major depressive disorder (MDD) is a leading global cause of disability, being more prevalent in females, possibly due to molecular and neuronal pathway differences between females and males. However, the connection between transcriptional changes and MDD remains unclear. We identified transcriptionally altered genes (TAGs) in MDD through gene and transcript expression analyses, focusing on sex-specific differences. Analyzing 263 brain samples from both sexes, we conducted differential gene expression, differential transcript expression, and differential transcript usage analyses, revealing 1169 unique TAGs, primarily in the prefrontal areas, with nearly half exhibiting transcript-level alterations. Females showed notable RNA splicing and export process disruptions in the orbitofrontal cortex, alongside altered DDX39B gene expression in five of the six brain regions in both sexes. Our findings suggest that disruptions in RNA processing pathways may play a vital role in MDD.

Therapeutic strategies to modulate gut microbial health: Approaches for sarcopenia management

Sarcopenia is a progressive and generalized loss of skeletal muscle and functions associated with ageing with currently no definitive treatment. Alterations in gut microbial composition have emerged as a significant contributor to the pathophysiology of multiple diseases. Recently, its association with muscle health has pointed to its potential role in mediating sarcopenia. The current review focuses on the association of gut microbiota and mediators of muscle health, connecting the dots between the influence of gut microbiota and their metabolites on biomarkers of sarcopenia. It further delineates the mechanism by which the gut microbiota affects muscle health with progressing age, aiding the formulation of a multi-modal treatment plan involving nutritional supplements and pharmacological interventions along with lifestyle changes compiled in the review. Nutritional supplements containing proteins, vitamin D, omega-3 fatty acids, creatine, curcumin, kefir, and ursolic acid positively impact the gut microbiome. Dietary fibres foster a conducive environment for the growth of beneficial microbes such as Bifidobacterium, Faecalibacterium, Ruminococcus, and Lactobacillus. Probiotics and prebiotics act by protecting against reactive oxygen species (ROS) and inflammatory cytokines. They also increase the production of gut microbiota metabolites like short-chain fatty acids (SCFAs), which aid in improving muscle health. Foods rich in polyphenols are anti-inflammatory and have an antioxidant effect, contributing to a healthier gut. Pharmacological interventions like faecal microbiota transplantation (FMT), non-steroidal anti-inflammatory drugs (NSAIDs), ghrelin mimetics, angiotensin-converting enzyme inhibitors (ACEIs), and butyrate precursors lead to the production of anti-inflammatory fatty acids and regulate appetite, gut motility, and microbial impact on gut health. Further research is warranted to deepen our understanding of the interaction between gut microbiota and muscle health for developing therapeutic strategies for ameliorating sarcopenic muscle loss.

Rehmannia glutinosa DC.-Lilium lancifolium Thunb. in the treatment of depression: a comprehensive review and perspectives

Background

In recent years, the incidence of depression, recognized as a serious psychological disorder, has escalated rapidly. Rehmannia glutinosa DC. (Scrophulariaceae; Rehmanniae Radix, Crude drug) and Lilium lancifolium Thunb. (Liliaceae; Lilii bulbus, Crude drug) constitute a classic anti-depressant combination, exhibiting pharmacological effects that include anti-depressive, anti-anxiety, and anti-inflammatory properties. Current clinical studies have demonstrated that Baihe Dihuang Decoction, a traditional Chinese herbal compound, is effective in treating depression. However, the majority of scholars have predominantly examined Rehmannia glutinosa and Lilium in isolation, and a comprehensive elucidation of their principal active metabolites and pharmacological mechanisms remains lacking.

Methods

A comprehensive literature search was conducted as of 29 September 2024, utilizing databases such as PubMed, CNKI, Wanfang Data, Baidu Scholar, and Google Scholar. Additionally, classical texts on Chinese herbal medicine, the Chinese Pharmacopoeia, as well as doctoral and master's theses, were included in the collected materials. The search employed specific terms including "R. glutinosa," "Lilium," "Baihe Dihuang decoction," "application of Baihe Dihuang decoction," "pathogenesis of depression," and "pharmacological action and mechanism of depression.

Results

This paper reviewed the traditional applications and dosages of the R. glutinosa-Lilium as documented in Chinese medical classics, thereby establishing a foundation for the contemporary development and clinical application of the classical formula Baihe Dihuang Decoction. Additionally, recent years have seen a comprehensive review of the pharmacological effects and mechanisms of R. glutinosa-Lilium and its principal metabolites in the context of depression.

Conclusion

This paper has reviewed the active metabolites of R. glutinosa-Lilium and demonstrated its efficacy in the treatment of depression, as well as its role in modulating the underlying mechanisms of the disorder. The findings aim to serve as a reference for further research into the mechanisms of depression, its clinical applications, and the development of novel therapeutic agents.

Alleviation of Immobilization Stress or Fecal Microbiota-Induced Insomnia and Depression-like Behaviors in Mice by Lactobacillus plantarum and Its Supplement

Insomnia (sleeplessness) is a potential symptom of stress-induced depression/anxiety (DA), which induces TNF-α expression. Therefore, this study aimed to examine the effect of Lactobacillus (Lactiplantibacillus) plantarum P72, isolated as a strain suppressing lipopolysaccharide-induced expression of TNF-α in Caco2 cells, on DA and insomnia in immobilization stress (IS)- or cultured fecal microbiota (cFM)-treated mice. Oral administration of live or heat-killed P72 (hP72) reduced IS- or cFM-induced DA-like behaviors. They also reduced sleep latency time (SLT) and enhanced sleep duration (SLD). Additionally, P72 upregulated γ-aminobutyric acid (GABA), GABAA receptor α1, serotonin, and 5-HT1A receptor expression, which were downregulated by IS or cFM. Hempseed oil (HO) alone was ineffective against IS-induced DA- and insomnia-like behaviors, but its combination with P72 (PH) or hP72 (hPH) showed enhanced efficacy, reducing DA- and insomnia-like behaviors more strongly than P72 or HO alone. These also reduced the number of NF-κB-positive cells and the expression of TNF-α in the prefrontal cortex and colon. These results imply that P72 and its combination with HO can alleviate DA and insomnia by upregulating serotonergic and GABAergic systems through the suppression of NF-κB signaling.

Relationship of Regular Laxative Use, Genetic Susceptibility of Depression, and Risk of Incident Depression in the General Population

Background: The relationship between laxative use and the risk of depression remains uncertain. We aimed to assess the prospective association of regular laxative use with the risk of incident depression and to examine whether genetic risk of depression modifies this association. Methods: Four hundred fifty thousand forty-five participants without depression at baseline and have complete information on laxative use from the UK Biobank were included. The study outcome was incident depression, derived from linkage to primary care records, hospital inpatient data, death register records, or self-reported medical conditions at follow-up visits. Results: During a median follow-up of 12.4 years, 18,651(4.1%) participants have developed depression. Regular laxative use was significantly associated with a higher risk of incident depression (vs. nonregular laxative use; adjusted hazard ratio [HR] = 1.78, 95% confidence interval [CI], 1.68-1.89). Genetic risk of depression did not significantly modify this association. The risk of incident depression increased with increasing types of laxatives used, with a HR of 1.89 (95%CI, 1.73-2.08) for use of single laxative type and 2.32 (95%CI, 1.82-2.96) for combined use of two or more laxative types (P for trend <0.001). The positive association between regular laxative use and incident depression was more pronounced in men (adjusted HR = 2.21, 95%CI, 1.96-2.48) versus women (adjusted HR = 1.67, 95%CI, 1.56-1.79; P interaction <0.001). Compared to those who did not use laxatives regularly and did not have constipation, participants who used laxatives regularly and had constipation had the highest risk of incident depression (adjusted HR = 2.33, 95%CI, 1.94-2.80). Conclusions: Regular laxative use was significantly associated with a higher risk of incident depression, especially in men.

Altered Gut Microbiota Patterns in Young Children with Recent Maltreatment Exposure

BACKGROUND

The brain and the intestinal microbiota are highly interconnected and especially vulnerable to disruptions in early life. Emerging evidence indicates that psychosocial adversity detrimentally impacts the intestinal microbiota, affecting both physical and mental health. This study aims to investigate the gut microbiome in young children in the immediate aftermath of maltreatment exposure.

METHODS

Maltreatment exposure was assessed in 88 children (ages 3-7) using the Maternal Interview for the Classification of Maltreatment [MICM]. Children were allocated to three groups according to the number of experienced maltreatment categories: no maltreatment, low maltreatment, and high maltreatment exposures. Stool samples were collected and analyzed by 16S rRNA sequencing.

RESULTS

Children subjected to high maltreatment exposure exhibited lower alpha diversity in comparison to those with both no and low maltreatment exposure (Simpson Index, Tukey post hoc, p = 0.059 and p = 0.007, respectively). No significant distinctions in beta diversity were identified. High maltreatment exposure was associated with the enrichment of several genera from the class Clostridia (Clostridium, Intestinibacter, Howardella and Butyrivibrio) and the depletion of the genus Phocaeicola (class Bacteriodia).

CONCLUSIONS

Severe maltreatment exposure is associated with alterations in the gut microbiota of young children. Longitudinal trajectories of intestinal microbiota composition in the context of maltreatment may reveal important insights related to psychiatric and somatic health outcomes.

Yeast supplementation potentiates fluoxetine's anti-depressant effect in mice via modulation of oxido-inflammatory, CREB, and MAPK signaling pathways

Introduction

The therapeutic potential of yeast in the management of depression is unknown. Thus, we evaluated the modulatory effect of nutritional yeast supplementation on antidepressant activity of fluoxetine in mice models of depressive-like behaviors (DLB).

Methods

A total of 112 mice were divided into 16 groups (n = 7 each) for a 3-stage study. Stage I (non-DLB study) had groups Ia (10 mL/kg vehicle), Ib (20 mg/kg fluoxetine), Ic - If (2% yeast diet for all, but Id - If additionally received 5 mg/kg, 10 mg/kg, and 20 mg/kg fluoxetine respectively). Stage II (lipopolysaccharide [LPS] model of DLB) had groups IIa - IIb (10 mL/kg vehicle), IIc (20 mg/kg fluoxetine), IId (yeast) and IIe (yeast + 20 mg/kg fluoxetine). After these treatments for 24 days, animals in IIb - IIe received 0.83 mg/kg of LPS on the 25th day. Except for group IIIa (10 mL/kg vehicle), animals in other groups of stage III (unpredictable chronic mild stress [UCMS] model) were exposed to UCMS for 24 days along with 10 mL/kg vehicle (IIIb), 20 mg/kg fluoxetine (IIIc), yeast (IIId), or yeast + fluoxetine (IIIe).

Results

Yeast and fluoxetine attenuated LPS- and UCMS-induced immobility, derangement of oxido-inflammatory (TNF-α, IL-6, NO, MDA, SOD, GSH, CAT, and AChE) and CREB/MAPK pathways. While fluoxetine had more potent effect than yeast when used separately, pre-treatment of mice with their combination had more pronounced effect than either of them.

Conclusion

Yeast supplementation improves the antidepressant activity of fluoxetine in mice by modulating oxido-inflammatory, CREB, and MAPK pathways.

Nutritional Modulation of the Gut-Brain Axis: A Comprehensive Review of Dietary Interventions in Depression and Anxiety Management

Mental health is an increasing topic of focus since more than 500 million people in the world suffer from depression and anxiety. In this multifactorial disorder, parameters such as inflammation, the state of the microbiota and, therefore, the patient's nutrition are receiving more attention. In addition, food products are the source of many essential ingredients involved in the regulation of mental processes, including amino acids, neurotransmitters, vitamins, and others. For this reason, this narrative review was carried out with the aim of analyzing the role of nutrition in depression and anxiety disorders. To reach the review aim, a critical review was conducted utilizing both primary sources, such as scientific publications and secondary sources, such as bibliographic indexes, web pages, and databases. The search was conducted in PsychINFO, MedLine (Pubmed), Cochrane (Wiley), Embase, and CinAhl. The results show a direct relationship between what we eat and the state of our nervous system. The gut-brain axis is a complex system in which the intestinal microbiota communicates directly with our nervous system and provides it with neurotransmitters for its proper functioning. An imbalance in our microbiota due to poor nutrition will cause an inflammatory response that, if sustained over time and together with other factors, can lead to disorders such as anxiety and depression. Changes in the functions of the microbiota-gut-brain axis have been linked to several mental disorders. It is believed that the modulation of the microbiome composition may be an effective strategy for a new treatment of these disorders. Modifications in nutritional behaviors and the use of ergogenic components are presented as important non-pharmacological interventions in anxiety and depression prevention and treatment. It is desirable that the choice of nutritional and probiotic treatment in individual patients be based on the results of appropriate biochemical and microbiological tests.

The gut microbiota: emerging biomarkers and potential treatments for infertility-related diseases

Infertility is a disease of impaired fertility. With socioeconomic development, changes in human lifestyles, and increased environmental pollution, the problem of low human fertility has become increasingly prominent. The incidence of global infertility is increasing every year. Many factors lead to infertility, and common female factors include tubal factors, ovulation disorders, endometriosis, and immune factors. The gut microbiota is involved in many physiological processes, such as nutrient absorption, intestinal mucosal growth, glycolipid metabolism, and immune system regulation. An altered gut flora is associated with female infertility disorders such as polycystic ovary syndrome (PCOS), endometriosis (EMs), and premature ovarian failure (POF). Dysbiosis of the gut microbiota directly or indirectly contributes to the development of female infertility disorders, which also affect the homeostasis of the gut microbiota. Identifying the etiology and pathogenesis of infertility in patients is the focus of reproductive medicine physicians. We studied the developmental mechanism between the gut microbiota and PCOS, EMs, and POF from a new perspective, providing new ideas for diagnosing and treating female infertility diseases and specific reference values for eugenics.

The gut microbiome: an important role in neurodegenerative diseases and their therapeutic advances

There are complex interactions between the gut and the brain. With increasing research on the relationship between gut microbiota and brain function, accumulated clinical and preclinical evidence suggests that gut microbiota is intimately involved in the pathogenesis of neurodegenerative diseases (NDs). Increasingly studies are beginning to focus on the association between gut microbiota and central nervous system (CNS) degenerative pathologies to find potential therapies for these refractory diseases. In this review, we summarize the changes in the gut microbiota in Alzheimer's disease, Parkinson's disease, multiple sclerosis, and amyotrophic lateral sclerosis and contribute to our understanding of the function of the gut microbiota in NDs and its possible involvement in the pathogenesis. We subsequently discuss therapeutic approaches targeting gut microbial abnormalities in these diseases, including antibiotics, diet, probiotics, and fecal microbiota transplantation (FMT). Furthermore, we summarize some completed and ongoing clinical trials of interventions with gut microbes for NDs, which may provide new ideas for studying NDs.

Exploring Causal Links Between Gut Microbiota and Geriatric Syndromes: A Two-Sample Mendelian Randomization Analysis

Background: Both observational studies and clinical trials have demonstrated a link between the gut microbiota and the geriatric syndrome. Nevertheless, the exact nature of this relationship, particularly concerning causality, remains elusive. Mendelian randomization (MR) is a method of inference based on genetic variation to assess the causal relationship between an exposure and an outcome. In this study, we conducted a two-sample Mendelian randomization (TSMR) study to fully reveal the potential genetic causal effects of gut microbiota on geriatric syndromes. Methods: This study used data from genome wide association studies (GWAS) to investigate causal relationships between the gut microbiota and geriatric syndromes, including frailty, Parkinson's disease (PD), delirium, insomnia, and depression. The primary causal relationships were evaluated using the inverse-variance weighted method, MR Egger, simple mode, weighted mode and weighted median. To assess the robustness of the results, horizontal pleiotropy was examined through MR-Egger intercept and MR-presso methods. Heterogeneity was assessed using Cochran's Q test, and sensitivity was evaluated via the leave-one-out method. Results: We identified 41 probable causal relationships between gut microbiota and five geriatric syndrome-associated illnesses using the inverse-variance weighted method. Frailty showed five positive and two negative causal relationships, while PD revealed three positive and four negative causal connections. Delirium showed three positive and two negative causal relationships. Similarly, insomnia demonstrated nine positive and two negative causal connections, while depression presented nine positive and two negative causal relationships. Conclusions: Using the TSMR method and data from the public GWAS database and, we observed associations between specific microbiota groups and geriatric syndromes. These findings suggest a potential role of gut microbiota in the development of geriatric syndromes, providing valuable insights for further research into the causal relationship between gut microbiota and these syndromes.

Ghrelin is associated with an elevated mood after an overnight fast in depression

BACKGROUND

Major depressive disorder (MDD) comprises subtypes with distinct symptom profiles. For example, patients with melancholic and atypical MDD differ in the direction of appetite and body weight changes as well as mood reactivity. Despite reported links to altered energy metabolism, the role of circulating neuropeptides from the gut in modulating such symptoms remains largely elusive.

METHODS

We collected data from 103 participants, including 52 patients with MDD and 51 healthy control participants (HCP). After an overnight fast, we measured plasma levels of (acyl and des-acyl) ghrelin and participants reported their current metabolic and mood states using visual analog scales (VAS). Furthermore, they completed symptom-related questionnaires (i.e., STAI-T).

RESULTS

Patients with atypical versus melancholic MDD reported less negative affect (p = 0.025). Higher levels of acyl ghrelin (corrected for BMI) were associated with improved mood (p = 0.012), specifically in patients with MDD. These associations of ghrelin were not mood-item specific and exceeded correlations with trait markers of negative affectivity. In contrast to associations with mood state, higher levels of ghrelin were not associated with increased hunger per se or changes in appetite in patients with MDD.

LIMITATIONS

The study is limited by the cross-sectional design without an intervention.

CONCLUSIONS

Our results reveal potentially mood-enhancing effects of ghrelin in fasting individuals that exceed associations with metabolic state ratings. These associations with circulating neuropeptides might help explain anti-depressive effects of fasting interventions and could complement conventional treatments in patients with melancholic MDD.

Co-decoction of Lilii bulbus and Radix Rehmannia Recens and its key bioactive ingredient verbascoside inhibit neuroinflammation and intestinal permeability associated with chronic stress-induced depression via the gut microbiota-brain axis

BACKGROUND

Gut microbiota plays a critical role in the pathogenesis of depression and are a therapeutic target via maintaining the homeostasis of the host through the gut microbiota-brain axis (GMBA). A co-decoction of Lilii bulbus and Radix Rehmannia Recens (LBRD), in which verbascoside is the key active ingredient, improves brain and gastrointestinal function in patients with depression. However, in depression treatment using verbascoside or LBRD, mechanisms underlying the bidirectional communication between the intestine and brain via the GMBA are still unclear.

PURPOSE

This study aimed to examine the role of verbascoside in alleviating depression via gut-brain bidirectional communication and to study the possible pathways involved in the GMBA.

METHODS

Key molecules and compounds involved in antidepressant action were identified using HPLC and transcriptomic analyses. The antidepressant effects of LBRD and verbascoside were observed in chronic stress induced depression model by behavioural test, neuronal morphology, and synaptic dendrite ultrastructure, and their neuroprotective function was measured in corticosterone (CORT)-stimulated nerve cell injury model. The causal link between the gut microbiota and the LBRD and verbascoside antidepressant efficacy was evaluate via gut microbiota composition analysis and faecal microbiota transplantation (FMT).

RESULTS

LBRD and Verbascoside administration ameliorated depression-like behaviours and synaptic damage by reversing gut microbiota disturbance and inhibiting inflammatory responses as the result of impaired intestinal permeability or blood-brain barrier leakiness. Furthermore, verbascoside exerted neuroprotective effects against CORT-induced cytotoxicity in an in vitro depression model. FMT therapy indicated that verbascoside treatment attenuated gut inflammation and central nervous system inflammatory responses, as well as eliminated neurotransmitter and brain-gut peptide deficiencies in the prefrontal cortex by modulating the composition of gut microbiota. Lactobacillus, Parabacteroides, Bifidobacterium, and Ruminococcus might play key roles in the antidepressant effects of LBRD via the GMBA.

CONCLUSION

The current study elucidates the multi-component, multi-target, and multi-pathway therapeutic effects of LBRD on depression by remodeling GMBA homeostasis and further verifies the causality between gut microbiota and the antidepressant effects of verbascoside and LBRD.

Effects of Maternal Diet on Infant Health: A Review Based on Entero-Mammary Pathway of Intestinal Microbiota

SCOPE

The microbes in breast milk are critical for the early establishment of infant gut microbiota and have important implications for infant health. Breast milk microbes primarily derive from the migration of maternal intestinal microbiota. This review suggests that the regulation of maternal diet on gut microbiota may be an effective strategy to improve infant health.

METHODS AND RESULTS

This article reviews the impact of breast milk microbiota on infant development and intestinal health. The close relationship between the microbiota in the maternal gut and breast through the entero-mammary pathway is discussed. Based on the effect of diet on gut microbiota, it is proposed that changing the maternal dietary structure is a new strategy for regulating breast milk microbiota and infant intestinal microbiota, which would have a positive impact on infant health.

CONCLUSION

Breast milk microbes have beneficial effects on infant development and regulation of the immune system. The mother's gut and breast can undergo certain bacterial migration through the entero-mammary pathway. Research has shown that intervening in a mother's diet during breastfeeding can affect the composition of the mother's gut microbiota, thereby regulating the microbiota of breast milk and infant intestines, and is closely related to infant health.

Peyer's Patch: Possible target for modulating the Gut-Brain-Axis through microbiota

The gastrointestinal (GI) tract and the brain form bidirectional nervous, immune, and endocrine communications known as the gut-brain axis. Several factors can affect this axis; among them, various studies have focused on the microbiota and imply that alterations in microbiota combinations can influence both the brain and GI. Also, many studies have shown that the immune system has a vital role in varying gut microbiota combinations. In the current paper, we will review the multidirectional effects of gut microbiota, immune system, and nervous system on each other. Specifically, this review mainly focuses on the impact of Peyer's patches as a critical component of the gut immune system on the gut-brain axis through affecting the gut's microbial composition. In this way, some factors were discussed as proposed elements of missing gaps in this field.

A probiotic NVP1704 alleviates stress-induced sleeplessness/depression-like symptoms in mice by upregulating serotonergic and GABAergic systems and downregulating NF-κB activation

Sleeplessness (insomnia) is a potential symptom of depression. A probiotic NVP1704 alleviates depression-like behavior and neuroinflammation in mice. Therefore, to understand whether NVP1704 could be effective against sleeplessness in vivo, we exposed immobilization stress (IS) in mice, then orally administered NVP1704 for 5 days, and assayed depression/anxiety-like behavior in the open field, elevated plus maze, and tail suspension tests, sleeping latency time, and sleep duration, euthanized then by exposure to CO2, and analyzed their related biomarkers. Oral administration of NVP1704 decreased IS-induced depression/anxiety-like behavior and sleeping latency time and increased IS-suppressed sleeping duration. NVP1704 increased IS-suppressed expression of γ-aminobutyric acid (GABA), GABAA receptor α1 (GABAARα1) and α2 subunits (GABAARα2), serotonin, 5-HT receptors (5-HT1AR and 5-HT1BR), and melatonin receptors (MT1R and MT2R) in the prefrontal cortex and thalamus. NVP1704 also increased the IS-suppressed GABAARα1-positive cell population in the prefrontal cortex and decreased IS-induced corticosterone, TNF-α, and IL-6 expression and the NF-κB+Iba1+ cell population in the brain and myeloperoxidase, TNF-α, and IL-6 expression and the NF-κB+CD11c+ cell population in the colon. Based on these findings, NVP1704 may alleviate depression/anxiety/sleeplessness-like behaviors through the upregulation of serotonergic and GABAergic systems and downregulation of NF-κB activation.

Stress-induced mucin 13 reductions drive intestinal microbiome shifts and despair behaviors

Depression is a prevalent psychological condition with limited treatment options. While its etiology is multifactorial, both chronic stress and changes in microbiome composition are associated with disease pathology. Stress is known to induce microbiome dysbiosis, defined here as a change in microbial composition associated with a pathological condition. This state of dysbiosis is known to feedback on depressive symptoms. While studies have demonstrated that targeted restoration of the microbiome can alleviate depressive-like symptoms in mice, translating these findings to human patients has proven challenging due to the complexity of the human microbiome. As such, there is an urgent need to identify factors upstream of microbial dysbiosis. Here we investigate the role of mucin 13 as an upstream mediator of microbiome composition changes in the context of stress. Using a model of chronic stress, we show that the glycocalyx protein, mucin 13, is selectively reduced after psychological stress exposure. We further demonstrate that the reduction of Muc13 is mediated by the Hnf4 transcription factor family. Finally, we determine that deleting Muc13 is sufficient to drive microbiome shifts and despair behaviors. These findings shed light on the mechanisms behind stress-induced microbial changes and reveal a novel regulator of mucin 13 expression.

Natural products for Gut-X axis: pharmacology, toxicology and microbiology in mycotoxin-caused diseases

Introduction: The gastrointestinal tract is integral to defending against external contaminants, featuring a complex array of immunological, physical, chemical, and microbial barriers. Mycotoxins, which are toxic metabolites from fungi, are pervasive in both animal feed and human food, presenting substantial health risks. Methods: This review examines the pharmacological, toxicological, and microbiological impacts of natural products on mycotoxicosis, with a particular focus on the gut-x axis. The analysis synthesizes current understanding and explores the role of natural products rich in polysaccharides, polyphenols, flavonoids, and saponins. Results: The review highlights that mycotoxins can disrupt intestinal integrity, alter inflammatory responses, damage the mucus layer, and disturb the bacterial balance. The toxins' effects are extensive, potentially harming the immune system, liver, kidneys, and skin, and are associated with serious conditions such as cancer, hormonal changes, genetic mutations, bleeding, birth defects, and neurological issues. Natural products have shown potential anticancer, anti-tumor, antioxidant, immunomodulatory, and antitoxic properties. Discussion: The review underscores the emerging therapeutic strategy of targeting gut microbial modulation. It identifies knowledge gaps and suggests future research directions to deepen our understanding of natural products' role in gut-x axis health and to mitigate the global health impact of mycotoxin-induced diseases.

Peptides Used for Heavy Metal Remediation: A Promising Approach

In recent years, heavy metal pollution has become increasingly prominent, severely damaging ecosystems and biodiversity, and posing a serious threat to human health. However, the results of current methods for heavy metal restoration are not satisfactory, so it is urgent to find a new and effective method. Peptides are the units that make up proteins, with small molecular weights and strong biological activities. They can effectively repair proteins by forming complexes, reducing heavy metal ions, activating the plant's antioxidant defense system, and promoting the growth and metabolism of microorganisms. Peptides show great potential for the remediation of heavy metal contamination due to their special structure and properties. This paper reviews the research progress in recent years on the use of peptides to remediate heavy metal pollution, describes the mechanisms and applications of remediation, and provides references for the remediation of heavy metal pollution.

Longitudinal microbiome investigation throughout prion disease course reveals pre- and symptomatic compositional perturbations linked to short-chain fatty acid metabolism and cognitive impairment in mice

Commensal intestinal bacteria shape our microbiome and have decisive roles in preserving host metabolic and immune homeostasis. They conspicuously impact disease development and progression, including amyloid-beta (Aβ) and alpha (α)-synuclein pathology in neurodegenerative diseases, conveying the importance of the brain-gut-microbiome axis in such conditions. However, little is known about the longitudinal microbiome landscape and its potential clinical implications in other protein misfolding disorders, such as prion disease. We investigated the microbiome architecture throughout prion disease course in mice. Fecal specimens were assessed by 16S ribosomal RNA sequencing. We report a temporal microbiome signature in prion disease and uncovered alterations in Lachnospiraceae, Ruminococcaceae, Desulfovibrionaceae, and Muribaculaceae family members in this disease. Moreover, we determined the enrichment of Bilophila, a microorganism connected to cognitive impairment, long before the clinical manifestation of disease symptoms. Based on temporal microbial abundances, several associated metabolic pathways and resulting metabolites, including short-chain fatty acids, were linked to the disease. We propose that neuroinflammatory processes relate to perturbations of the intestinal microbiome and metabolic state by an interorgan brain-gut crosstalk. Furthermore, we describe biomarkers possibly suitable for early disease diagnostics and anti-prion therapy monitoring. While our study is confined to prion disease, our discoveries might be of equivalent relevance in other proteinopathies and central nervous system pathologies.

How Diet and Lifestyle Can Fine-Tune Gut Microbiomes for Healthy Aging

Many physical, social, and psychological changes occur during aging that raise the risk of developing chronic diseases, frailty, and dependency. These changes adversely affect the gut microbiota, a phenomenon known as microbe-aging. Those microbiota alterations are, in turn, associated with the development of age-related diseases. The gut microbiota is highly responsive to lifestyle and dietary changes, displaying a flexibility that also provides anactionable tool by which healthy aging can be promoted. This review covers, firstly, the main lifestyle and socioeconomic factors that modify the gut microbiota composition and function during healthy or unhealthy aging and, secondly, the advances being made in defining and promoting healthy aging, including microbiome-informed artificial intelligence tools, personalized dietary patterns, and food probiotic systems.

Brain-gut photobiomodulation restores cognitive alterations in chronically stressed mice through the regulation of Sirt1 and neuroinflammation

BACKGROUND

Chronic stress is an important risk factor for the development of major depressive disorder (MDD). Recent studies have shown microbiome dysbiosis as one of the pathogenic mechanisms associated with MDD. Thus, it is important to find novel non-pharmacological therapeutic strategies that can modulate gut microbiota and brain activity. One such strategy is photobiomodulation (PBM), which involves the non-invasive use of light.

OBJECTIVE/HYPOTHESIS

Brain-gut PBM could have a synergistic beneficial effect on the alterations induced by chronic stress.

METHODS

We employed the chronic unpredictable mild stress (CUMS) protocol to induce a depressive-like state in mice. Subsequently, we administered brain-gut PBM for 6 min per day over a period of 3 weeks. Following PBM treatment, we examined behavioral, structural, molecular, and cellular alterations induced by CUMS.

RESULTS

We observed that the CUMS protocol induces profound behavioral alterations and an increase of sirtuin1 (Sirt1) levels in the hippocampus. We then combined the stress protocol with PBM and found that tissue-combined PBM was able to rescue cognitive alterations induced by CUMS. This rescue was accompanied by a restoration of hippocampal Sirt1 levels, prevention of spine density loss in the CA1 of the hippocampus, and the modulation of the gut microbiome. PBM was also effective in reducing neuroinflammation and modulating the morphology of Iba1-positive microglia.

LIMITATIONS

The molecular mechanisms behind the beneficial effects of tissue-combined PBM are not fully understood.

CONCLUSIONS

Our results suggest that non-invasive photobiomodulation of both the brain and the gut microbiome could be beneficial in the context of stress-induced MDD.

How gut microbiota may impact ocular surface homeostasis and related disorders

Changes in the bacterial flora in the gut, also described as gut microbiota, are readily acknowledged to be associated with several systemic diseases, especially those with an inflammatory, neuronal, psychological or hormonal factor involved in the pathogenesis and/or the perception of the disease. Maintaining ocular surface homeostasis is also based on all these four factors, and there is accumulating evidence in the literature on the relationship between gut microbiota and ocular surface diseases. The mechanisms involved are mostly interconnected due to the interaction of central and peripheral neuronal networks, inflammatory effectors and the hormonal system. A better understanding of the influence of the gut microbiota on the maintenance of ocular surface homeostasis, and on the onset or persistence of ocular surface disorders could bring new insights and help elucidate the epidemiology and pathology of ocular surface dynamics in health and disease. Revealing the exact nature of these associations could be of paramount importance for developing a holistic approach using highly promising new therapeutic strategies targeting ocular surface diseases.

Long-term intake of thermo-induced oxidized oil results in anxiety-like and depression-like behaviors: involvement of microglia and astrocytes

Frequent consumption of fried foods has been strongly associated with a higher risk of anxiety and depression, particularly among young individuals. The existing evidence has indicated that acrylamide produced from starchy foods at high temperatures can induce anxious behavior. However, there is limited research on the nerve damage caused by thermo-induced oxidized oil (TIOO). In this study, we conducted behavioral tests on mice and found that prolonged consumption of TIOO led to significant anxiety behavior and a tendency toward depression. TIOO primarily induced these two emotional disorders by affecting the differentiation of microglia, the level of inflammatory factors, the activation of astrocytes, and glutamate circulation in brain tissue. By promoting the over-differentiation of microglia into M1 microglia, TIOO disrupted their differentiation balance, resulting in an up-regulation of inflammatory factors (IL-1β, IL-6, TNF-α, NOS2) in M1 microglia and a down-regulation of neuroprotective factors IL-4/IL-10 in M2 microglia, leading to nerve damage. Moreover, TIOO activated astrocytes, accelerating their proliferation and causing GFAP precipitation, which damaged astrocytes. Meanwhile, TIOO stimulates the secretion of the BDNF and reduces the level of the glutamate receptor GLT-1 in astrocytes, leading to a disorder in the glutamate-glutamine cycle, further exacerbating nerve damage. In conclusion, this study suggests that long-term intake of thermo-induced oxidized oil can trigger symptoms of anxiety and depression.