Transit time affects the community stability of Lactobacillus and Bifidobacterium species in an in vitro model of human colonic microbiotia

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.

Oral Troxerutin Alleviates Depression Symptoms in Mice by Modulating Gut Microbiota and Microbial Metabolism

SCOPE

A growing body of evidence suggests that the harmful gut microbiota in depression patients can play a role in the progression of depression. There is limited research on troxerutin's impact on the central nervous system (CNS), especially in depression. The study finds that troxerutin effectively alleviates depression and anxiety-like behavior in mice by increasing the abundance of beneficial bacteria like Lactobacillus and Firmicutes while decreasing the abundance of harmful bacteria like Proteobacteria, Bacteroides, and Actinobacteria in the gut. Furthermore, the research reveals that troxerutin regulates various metabolic pathways in mice, including nucleotide metabolism, caffeine metabolism, purine metabolism, arginine biosynthesis, histidine metabolism, 2-oxocarboxylic acid metabolism, biosynthesis of amino acids, glycine, serine and threonine metabolism, and Arginine and proline metabolism.

CONCLUSIONS

In conclusion, the study provides compelling evidence for the antidepressant efficacy of troxerutin. Through the investigation of the role of intestinal microorganisms and metabolites, the study identifies these factors as key players in troxerutin's ability to prevent depression. Troxerutin achieves its neuroprotective effects and effectively prevents depression and anxiety by modulating the abundance of gut microbiota, including Proteobacteria, Bacteroides, and Actinobacteria, as well as regulating metabolites such as creatine.

Multilayer Coating with Red Ginseng Dietary Fiber Improves Intestinal Adhesion and Proliferation of Probiotics in Human Intestinal Epithelial Models

To exert their beneficial effects, it is essential for the commensal bacteria of probiotic supplements to be sufficiently protected as they pass through the low pH environment of the stomach, and effectively colonize the intestinal epithelium downstream. Here, we investigated the effect of a multilayer coating containing red ginseng dietary fiber, on the acid tolerance, and the adhesion and proliferation capacities of three Lactobacillus strains (Limosilactobacillus reuteri KGC1901, Lacticaseibacillus casei KGC1201, Limosilactobacillus fermentum KGC1601) isolated from Panax ginseng, using HT-29 cells, mucin-coated plates, and human pluripotent stem cell-derived intestinal epithelial cells as in vitro models of human gut physiology. We observed that the multilayer-coated strains displayed improved survival rates after passage through gastric juice, as well as high adhesion and proliferation capacities within the various gut epithelial systems tested, compared to their uncoated counterparts. Our findings demonstrated that the multilayer coat effectively protected commensal microbiota and led to improved adhesion and colonization of intestinal epithelial cells, and consequently to higher probiotic efficacy.

Effect of Operational Parameters on the Cultivation of the Gut Microbiome in Continuous Bioreactors Inoculated with Feces: A Systematic Review

Since the early 1980s, multiple researchers have contributed to the development of in vitro models of the human gastrointestinal system for the mechanistic interrogation of the gut microbiome ecology. Using a bioreactor for simulating all the features and conditions of the gastrointestinal system is a massive challenge. Some conditions, such as temperature and pH, are readily controlled, but a more challenging feature to simulate is that both may vary in different regions of the gastrointestinal tract. Promising solutions have been developed for simulating other functionalities, such as dialysis capabilities, peristaltic movements, and biofilm growth. This research field is under constant development, and further efforts are needed to drive these models closer to in vivo conditions, thereby increasing their usefulness for studying the gut microbiome impact on human health. Therefore, understanding the influence of key operational parameters is fundamental for the refinement of the current bioreactors and for guiding the development of more complex models. In this review, we performed a systematic search for operational parameters in 229 papers that used continuous bioreactors seeded with human feces. Despite the reporting of operational parameters for the various bioreactor models being variable, as a result of a lack of standardization, the impact of specific operational parameters on gut microbial ecology is discussed, highlighting the advantages and limitations of the current bioreactor systems.

Gut microbiota: A new target for traditional Chinese medicine in the treatment of depression

ETHNIC PHARMACOLOGICAL RELEVANCE

The causes of depression are complex. Many factors are involved in its pathogenesis, including the individual's biological and social environment. Although numerous studies have reported that the gut microbiota plays a significant role in depression, drugs that regulate the gut microbiota to treat depression have not yet been comprehensively reviewed. At the same time, more and more attention has been paid to the characteristics of traditional Chinese medicine (TCM) in improving depression by regulating gut microbiota. In ancient times, fecal microbiota transplantation was recorded in TCM for the treatment of severe diseases. There are also records in Chinese ancient books about the use of TCM to adjust gut microbiota to treat diseases, which has opened up a unique research field in TCM. Therefore, this article focuses on the pharmacological effects, targets, and mechanisms of TCM in improving depression by mediating the influence of gut microbiota.

AIM OF THIS REVIEW

To summarize the role the gut microbiota plays in depression, highlight potential regulatory targets, and elucidate the anti-depression mechanisms of TCMs through regulation of the gut microbiota.

METHODS

A systematic review of 256 clinical trials and pharmaceutical studies published until June 2022 was conducted in eight electronic databases (Web of Science, PubMed, SciFinder, Research Gate, ScienceDirect, Google Scholar, Scopus, and China Knowledge Infrastructure), according to the implemented PRISMA criteria, using the search terms "traditional Chinese medicine," "depression," and "gut microbiota."

RESULTS

Numerous studies reported the effects of different gut bacteria on depression and that antidepressants work through the gut microbiota. TCM preparations based on compound Chinese medicine, the Chinese Materia Medica, and major bioactive components exerted antidepressant-like effects by improving levels of neurotransmitters, short-chain fatty acids, brain-derived neurotrophic factor, kynurenine, and cytokines via regulation of the gut microbiota.

CONCLUSION

This review summarized the anti-depression effects of TCM on the gut microbiota, providing evidence that TCMs are safe and effective in the treatment of depression and may provide a new therapeutic approach.

Effect of faecal microbial transplant via colonoscopy in patients with severe obesity and insulin resistance: A randomized double-blind, placebo-controlled Phase 2 trial

AIM

To assess the effects of faecal microbial transplant (FMT) from lean people to subjects with obesity via colonoscopy.

MATERIAL AND METHODS

In a double-blind, randomized controlled trial, subjects with a body mass index ≥ 35 kg/m² and insulin resistance were randomized, in a 1:1 ratio in blocks of four, to either allogenic (from healthy lean donor; n = 15) or autologous FMT (their own stool; n = 13) delivered in the caecum and were followed for 3 months. The main outcome was homeostatic model assessment of insulin resistance (HOMA-IR) and secondary outcomes were glycated haemoglobin levels, lipid profile, weight, gut hormones, endotoxin, appetite measures, intestinal microbiome (IM), metagenome, serum/faecal metabolites, quality of life, anxiety and depression scores.

RESULTS

In the allogenic versus autologous groups, HOMA-IR and clinical variables did not change significantly, but IM and metabolites changed favourably (P < 0.05): at 1 month, Coprococcus, Bifidobacterium, Bacteroides and Roseburia increased, and Streptococcus decreased; at 3 months, Bacteroides and Blautia increased. Several species also changed significantly. For metabolites, at 1 month, serum kynurenine decreased and faecal indole acetic acid and butenylcarnitine increased, while at 3 months, serum isoleucine, leucine, decenoylcarnitine and faecal phenylacetic acid decreased. Metagenomic pathway representations and network analyses assessing relationships with clinical variables, metabolites and IM were significantly enhanced in the allogenic versus autologous groups. LDL and appetite measures improved in the allogenic (P < 0.05) but not in the autologous group.

CONCLUSIONS

Overall, in those with obeisty, allogenic FMT via colonoscopy induced favourable changes in IM, metabolites, pathway representations and networks even though other metabolic variables did not change. LDL and appetite variables may also benefit.

Microbiome in Anxiety and Other Psychiatric Disorders

Initial studies suggested that the fluctuations in the quantity, variety, and composition of the gut microbiota can significantly affect disease processes. This change in the gut microbiota causing negative health benefits was coined dysbiosis. Initial research focused on gastrointestinal illnesses. However, the gut microbiome was found to affect more than just gastrointestinal diseases. Numerous studies have proven that the gut microbiome can influence neuropsychiatric diseases such as Parkinson's disease, Alzheimer's disease, and multiple sclerosis.

The Gut-Brain Axis: Literature Overview and Psychiatric Applications

IMPORTANCE

Literature exploring the relationship between the intestinal microbiome and its effects on general health and well-being has grown significantly in recent years, and our knowledge of this subject continues to grow. Mounting evidence indicates that the intestinal microbiome is a potential target for therapeutic intervention in psychiatric illness and in neurodegenerative disorders such as Alzheimer disease. It is reasonable to consider modulating not just a patient's neurochemistry, behavior, or cognitive habits, but also their intestinal microbiome in an effort to improve psychiatric symptoms.

OBSERVATIONS

In this review paper, we show that intestinal microbiota possess the ability to directly influence both physical and mental well-being; therefore, should be included in future discussions regarding psychiatric treatment.

CONCLUSIONS

Clinicians are encouraged to consider patients' gut health when evaluating and treating psychiatric conditions, such as anxiety and depression. Optimization and diversification of gut flora through the use of psychobiotics-probiotics that confer mental health benefits-may soon become standard practice in conjunction with traditional psychiatric treatment modalities such as pharmacotherapy and psychotherapy.

Gut microbes in neurocognitive and mental health disorders

INTRODUCTION

As individuals age, the prevalence of neurocognitive and mental health disorders increases. Current biomedical treatments do not completely address the management of these conditions. Despite new pharmacological therapy the challenges of managing these diseases remain.There is increasing evidence that the Gut Microbiome (GM) and microbial dysbiosis contribute to some of the more prevalent mental health and neurocognitive disorders, such as depression, anxiety, obsessive-compulsive disorder (OCD), post-traumatic stress disorder (PTSD), schizophrenia, bipolar disorder (BP), and dementia as well as the behavioural and psychological symptoms of dementia (BPSD) through the microbiota-gut-brain axis. Methodology: Scoping review about the effect of gut microbiota on neurocognitive and mental health disorders.

RESULTS

This scoping review found there is an evolving evidence of the involvement of the gut microbiota in the pathophysiology of neurocognitive and mental health disorders. This manuscript also discusses how the psychotropics used to treat these conditions may have an antimicrobial effect on GM, and the potential for new strategies of management with probiotics and faecal transplantation.

CONCLUSIONS

This understanding can open up the need for a gut related approach in these disorders as well as unlock the door for the role of gut related microbiota management. KEY MESSAGES Challenges of managing mental health conditions remain in spite of new pharmacological therapy. Gut dysbiosis is seen in various mental health conditions. Various psychotropic medications can have an influence on the gut microbiota by their antimicrobial effect.

Alginate-based drug oral targeting using bio-micro/nano encapsulation technologies

INTRODUCTION

Oral delivery is the most common administrated drug delivery path. However, oral administration of lipophilic drugs has some limitations: they have poor dose-response due to low and varied dissolution kinetics and oral bioavailability with sub-optimal dissolution within the aqueous gastrointestinal microenvironment. Therefore, there is a need for robust formulating methods that protect the drug until it reaches to its optimum absorption site, allowing its optimum pharmacological effects via increasing its intestinal permeation and bioavailability.

AREA COVERED

Herein, we provide insights on orally administered lipophilic drug delivery systems. The detailed description of the obstacles associated with the oral bioavailability of lipophilic drugs are also discussed. Following this, techniques to overcome these obstacles with much emphasis on optimal safety and efficacy are addressed. Newly designed ionic vibrational jet flow encapsulation technology has enormous growth in lipophilic drug delivery systems, which is discussed thereafter.

EXPERT OPINION

Researchers have shown interest in drug's encapsulation. A combination of drug-bile acid and microencapsulation methods can be one promising strategy to improve the oral delivery of lipophilic drugs. However, the most critical aspect of this approach is the selection of bile acids, polymer, and encapsulation technology.

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

The complex bidirectional communication between the gut and the brain is finely orchestrated by different systems, including the endocrine, immune, autonomic, and enteric nervous systems. Moreover, increasing evidence supports the role of the microbiome and microbiota-derived molecules in regulating such interactions; however, the mechanisms underpinning such effects are only beginning to be resolved. Microbiota-gut peptide interactions are poised to be of great significance in the regulation of gut-brain signaling. Given the emerging role of the gut-brain axis in a variety of brain disorders, such as anxiety and depression, it is important to understand the contribution of bidirectional interactions between peptide hormones released from the gut and intestinal bacteria in the context of this axis. Indeed, the gastrointestinal tract is the largest endocrine organ in mammals, secreting dozens of different signaling molecules, including peptides. Gut peptides in the systemic circulation can bind cognate receptors on immune cells and vagus nerve terminals thereby enabling indirect gut-brain communication. Gut peptide concentrations are not only modulated by enteric microbiota signals, but also vary according to the composition of the intestinal microbiota. In this review, we will discuss the gut microbiota as a regulator of anxiety and depression, and explore the role of gut-derived peptides as signaling molecules in microbiome-gut-brain communication. Here, we summarize the potential interactions of the microbiota with gut hormones and endocrine peptides, including neuropeptide Y, peptide YY, pancreatic polypeptide, cholecystokinin, glucagon-like peptide, corticotropin-releasing factor, oxytocin, and ghrelin in microbiome-to-brain signaling. Together, gut peptides are important regulators of microbiota-gut-brain signaling in health and stress-related psychiatric illnesses.

Altered colonic function and microbiota profile in a mouse model of chronic depression

BACKGROUND

Depression often coexists with the irritable bowel syndrome (IBS) which is characterized by alterations in gut function. There is emerging evidence that the microbial composition (microbiota) of the gut is altered in IBS, but the basis for this is poorly understood. The aim of this study was to determine whether the induction of chronic depression results in changes in the colonic function and in its microbial community, and to explore underlying mechanisms.

METHODS

Bilateral olfactory bulbectomy (OBx) was used to induce depression-like behavior in mice. Colonic function was assessed by measuring muscle contractility, pellet excretion, c-fos activity, and serotonin levels. Microbiota profiles were obtained using denaturing gradient gel electrophoresis (DGGE). The hypothalamic-pituitary axis (HPA) was assessed by the hypothalamic expression of corticotropin-releasing hormone (CRH). In separate studies, mice without OBx received CRH via intracerebroventricular (ICV) infusion for 4 weeks prior to assessing colonic function and microbiota profiles.

KEY RESULTS

Olfactory bulbectomy mice demonstrated chronic depression- and anxiety-like behaviors associated with elevated central CRH expression and increases in c-Fos activity, serotonin levels, and motility in the colon. These changes were accompanied by an altered intestinal microbial profile. Central CRH administration produced similar changes in behavior and motility and altered the microbiota profile in the colon.

CONCLUSIONS & INFERENCES

The induction of chronic depression alters motor activity and the microbial profile in the colon likely via activation of the HPA. These findings provide a basis for linking the behavioral and gastrointestinal manifestations of IBS.

Design of a novel gut bacterial adhesion model for probiotic applications

A new gut bacterial adhesion model has been developed. For this, a continuous-flow bioreactor packed with bacteria-coated beads was designed to simulate the gut lining and other features. In vitro model efficacy shows successful bacterial cell gut adhesions: bacterial adhesion was higher with mucin-alginate compared to controls. In feasibility study, adhesion of Lactobacillus fermentum NCIMB 5221 and Lactobacillus reuteri NCIMB 701359 was investigated for their metabolic activities for bile salt. Bile salt hydrolase (BSH)-active Lactobacillus reuteri exerted higher activity than non-BSH-active L. fermentum. This model has potential use in gut health, probiotic, bacterial cell gut adhesion and other delivery applications.