The Intestinal Microbiota in Inflammatory Bowel Disease

The epithelial C15ORF48/miR-147-NDUFA4 axis is an essential regulator of gut inflammation, energy metabolism, and the microbiome

Chronic inflammation is epidemiologically linked to the pathogenesis of gastrointestinal diseases, including inflammatory bowel disease (IBD) and colorectal cancer (CRC). However, our understanding of the molecular mechanisms controlling gut inflammation remains insufficient, hindering the development of targeted therapies for IBD and CRC. In this study, we uncovered C15ORF48/miR-147 as a negative regulator of gut inflammation, operating through the modulation of epithelial cell metabolism. C15ORF48/miR-147 encodes two molecular products, C15ORF48 protein and miR-147-3p microRNA, which are predominantly expressed in the intestinal epithelium. C15ORF48/miR-147 ablation leads to gut dysbiosis and exacerbates chemically induced colitis in mice. C15ORF48 and miR-147-3p work together to suppress colonocyte metabolism and inflammation by silencing NDUFA4, a subunit of mitochondrial complex IV (CIV). Interestingly, the C15ORF48 protein, a structural paralog of NDUFA4, contains a unique C-terminal α-helical domain crucial for displacing NDUFA4 from CIV and its subsequent degradation. NDUFA4 silencing hinders NF-κB signaling activation and consequently attenuates inflammatory responses. Collectively, our findings have established the C15ORF48/miR-147-NDUFA4 molecular axis as an indispensable regulator of gut homeostasis, bridging mitochondrial metabolism and inflammation.

Crohn's disease

Crohn's disease is a chronic inflammatory disease of the gastrointestinal tract that might lead to progressive bowel damage and disability. The exact cause of Crohn's disease is unknown, but evidence points towards multifactorial events causing dysregulation of the innate immune system in genetically susceptible people. Commonly affecting the terminal ileum and proximal colon, Crohn's disease inflammation is often discontinuous and patchy, segmental, and transmural. Identification of characteristic findings on ileocolonoscopy and histology remains the diagnostic gold standard, but complete assessment involves laboratory abnormalities, including micronutrient deficiencies, cross-sectional imaging to identify transmural disease extent, severity and complications, and a psychosocial assessment. Treatment strategies for patients with Crohn's disease now go beyond achieving clinical remission to include deeper targets of endoscopic healing and consideration of adjunctive histological and transmural targets to alter disease progression potentially further. The use of early effective advanced therapies and development of therapies targeting alternative novel pathways with improved safety profiles have resulted in a new era of healing in Crohn's disease management. Future combination of advanced therapies with diet or other biological drugs and small molecules, together with improvements in tight control monitoring tools and predictive biomarkers might continue to improve outcomes for patients with Crohn's disease.

The epithelium takes the stage in asthma and inflammatory bowel diseases

The epithelium is a dynamic barrier and the damage to this epithelial layer governs a variety of complex mechanisms involving not only epithelial cells but all resident tissue constituents, including immune and stroma cells. Traditionally, diseases characterized by a damaged epithelium have been considered "immunological diseases," and research efforts aimed at preventing and treating these diseases have primarily focused on immuno-centric therapeutic strategies, that often fail to halt or reverse the natural progression of the disease. In this review, we intend to focus on specific mechanisms driven by the epithelium that ensure barrier function. We will bring asthma and Inflammatory Bowel Diseases into the spotlight, as we believe that these two diseases serve as pertinent examples of epithelium derived pathologies. Finally, we will argue how targeting the epithelium is emerging as a novel therapeutic strategy that holds promise for addressing these chronic diseases.

Effect of chronic low-dose treatment with chitooligosaccharides on microbial dysbiosis and inflammation associated chronic ulcerative colitis in Balb/c mice

The study aimed to investigate the potential of low dose chitooligosaccharide (COS) in ameliorating dextran sodium sulfate (DSS) induced chronic colitis by regulating microbial dysbiosis and pro-inflammatory responses. Chronic colitis was induced in BALB/c mice by DSS (4% w/v, 3 cycles of 5 days) administration. The mice were divided into four groups: vehicle, DSS, DSS + mesalamine and DSS+COS. COS and mesalamine were administered orally, daily once, from day 1 to day 30 at a dose of 20 mg/kg and 50 mg/kg respectively. The disease activity index (DAI), colon length, histopathological score, microbial composition, and pro-inflammatory cytokine expression were evaluated. COS (20 mg/kg, COSLow) administration reduced the disease activity index, and colon shortening, caused by DSS significantly. Furthermore, COSLow restored the altered microbiome in the gut and inhibited the elevated pro-inflammatory cytokines (IL-1 and IL-6) in the colon against DSS-induced chronic colitis in mice. Moreover, COSLow treatment improved the probiotic microflora thereby restoring the gut homeostasis. In conclusion, this is the first study where microbial dysbiosis and pro-inflammatory responses were modulated by chronic COSLow treatment against DSS-induced chronic colitis in Balb/c mice. Therefore, COS supplementation at a relatively low dose could be efficacious for chronic inflammatory bowel disease.

A metabolomics-driven model for early remission prediction following vedolizumab treatment in patients with moderate-to-severe active ulcerative colitis

To predict early remission following anti-integrin therapy (vedolizumab [VDZ]) in patients with moderate-to-severe active ulcerative colitis (UC) using non-invasive biomarkers. The clinical data of a cohort of 33 patients with moderate-to-severe active UC admitted to the Department of Gastroenterology at Suzhou Municipal Hospital between January 2021 and December 2022 were collected. Of these, 9 patients declined VDZ treatment, and 21 received VDZ at doses of 300 mg weeks 0, 2, and 6, each administered within a 30-minute infusion period. The treatment regimen aimed to induce remission of clinical symptoms; hence, the same dose was administered every 8 weeks. At weeks 0 and 14, serum C-reactive protein (CRP) and erythrocyte sedimentation rate were measured using a modified Mayo score. In addition to clinical assessment, stool samples at baseline and weeks 14 were collected and evaluated using 16SrRNA gene sequencing and gas chromatography-mass spectrometry (GC-MS). Clinical remission was determined based on the clinical symptoms and partial Mayo scores. In patients who received VDZ, the strains of bifidobacterium longum (P = 0.022) and bacteroides sartorii (P = 0.039) significantly increased after treatment than before treatment. GC-MS analysis showed that taurine (P = 0.047) and putrescine (P = 0.035) significantly decreased after treatment. Furthermore, while acetamide exhibited a notable increase (P = 0.001), arachidic acid (P < 0.001) and behenic acid (P = 0.005) demonstrated statistically significant elevations. The combined prediction model of acetamide, taurine, and putrescine demonstrated a high predictive value of early remission in patients with moderate-to-severe active UC following VDZ treatment (area under the curve = 0.911, P = 0.014).

Gut-Brain Axis a Key Player to Control Gut Dysbiosis in Neurological Diseases

Parkinson's disease is a chronic neuropathy characterised by the formation of Lewy bodies (misfolded alpha-synuclein) in dopaminergic neurons of the substantia nigra and other parts of the brain. Dopaminergic neurons play a vital role in generating both motor and non-motor symptoms. Finding therapeutic targets for Parkinson's disease (PD) is hindered due to an incomplete understanding of the disease's pathophysiology. Existing evidence suggests that the gut microbiota participates in the pathogenesis of PD via immunological, neuroendocrine, and direct neural mechanisms. Gut microbial dysbiosis triggers the loss of dopaminergic neurons via mitochondrial dysfunction. Gut dysbiosis triggers bacterial overgrowth in the small intestine, which increases the permeability barrier and induces systemic inflammation. It results in excessive stimulation of the innate immune system. In addition to that, activation of enteric neurons and enteric glial cells initiates the aggregation of alpha-synuclein. This alpha-synucleinopathy thus affects all levels of the brain-gut axis, including the central, autonomic, and enteric nervous systems. Though the neurobiological signaling cascade between the gut microbiome and the central nervous system is poorly understood, gut microbial metabolites may serve as a promising therapeutic strategy for PD. This article summarises all the known possible ways of bidirectional signal communication, i.e., the "gut-brain axis," where microbes from the middle gut interact with the brain and vice versa, and highlights a unique way to treat neurodegenerative diseases by maintaining homeostasis. The tenth cranial nerve (vagus nerve) plays a significant part in this signal communication. However, the leading regulatory factor for this axis is a diet that helps with microbial colonisation and brain function. Short-chain fatty acids (SCFAs), derived from microbially fermented dietary fibres, link host nutrition to maintain intestinal homeostasis. In addition to that, probiotics modulate cognitive function and the metabolic and behavioural conditions of the body. As technology advances, new techniques will emerge to study the tie-up between gut microbes and neuronal diseases.

Favipiravir Protects Enterocytes From Cell Death After Inflammatory Storm

Over the past years, inflammatory bowel disease (IBD) treatment has become more targeted, anticipating the use of immune-modifying therapies at an earlier stage. During the treatment process prevention and management of viral infections hold significant importance. The protective role of favipiravir on enterocytes which are affected by inflammation is still unknown. We aim to analyze the effects of favipiravir on enterocytes after an inflammatory condition. We conducted a 2,5-diphenyl-2H-tetrazolium bromide (MTT) assay to assess the cytotoxicity of favipiravir on intestinal epithelioid cells (IEC-6). To mimic the inflammation model in cell culture conditions, we exposed IEC-6 cells to tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ). The cells were categorized into four groups: control, inflammation model, application of favipiravir before inflammation (prophylactic), and application of favipiravir after inflammation (treatment). We assessed the presence and distribution of caspase 1, caspase 3, interleukin 6 (IL6), interleukin 8 (IL8), mixed lineage kinase domain-like protein (MLKL), receptor-interacting protein kinase 1 (RIPK1), and TNF-α using indirect immunoperoxidase staining. TNF-α and IL8 levels were analyzed with enzyme-linked immunosorbent assay (ELISA) in a culture medium. Caspase 1 was observed to be strong (+++) in the treatment group and weak (+) in the prophylactic group compared to the inflammation group. Caspase 3 was weak (+) in the inflammation group, and it was strong (+++) in the prophylactic and treatment group, the increase in the treatment group was significant. Therefore administering favipiravir before inducing inflammation appears to control the inflammatory caspase pathway in intestinal enterocytes, protecting them from inflammatory responses, while the caspase 3-dependent apoptotic pathway may not be active in enterocytes during inflammation. IL6 and IL8 were negative (-) in control, IL6 was weak (+) in inflammation and favipiravir treated groups; IL8 increased significantly in favipiravir groups compared to control and inflammation groups. Consequently, favipiravir may trigger IL6 release, initiating the inflammatory pathway and potentially enhancing IL8 interactions with other cytokines. TNF-α immunoreactivity was strong (+++) in the inflammation group, while it was moderate (++) in favipiravir-administered groups. MLKL immunoreactivity was strong (+++) in all groups, RIPK1 was weak (+) in control, strong (+++) in the inflammation and treatment group, moderate (++) in the prophylactic group, and the increase in inflammation and treatment group was significant compared to control. Our findings suggest that in the treatment group, necroptosis was triggered by increased MLKL and RIPK1, key players in inflammation and cell death. After immunocytochemical evaluation, our findings suggest that, after the onset of inflammation, favipiravir may play a role in cell death by increasing necroptosis rather than apoptosis.

Health Benefits of Montmorency Tart Cherry Juice Supplementation in Adults with Mild to Moderate Ulcerative Colitis: A Protocol for a Placebo Randomized Controlled Trial

Ulcerative colitis, characterized by its relapsing and remissive nature, negatively affects perception, body image, and overall quality of life. The associated financial burden underscores the need for alternative treatment approaches with fewer side effects, alongside pharmaceutical interventions. Montmorency tart cherries, rich in anthocyanins, have emerged as a potential natural anti-inflammatory agent for ulcerative colitis. This manuscript outlines the study protocol for a randomized placebo-controlled trial investigating the effects of Montmorency tart cherry in individuals with ulcerative colitis. The trial aims to recruit 40 participants with mild to moderate disease activity randomly assign them to either a Montmorency tart cherry or placebo group. The intervention will span 6 weeks, with baseline and 6-week assessments. The primary outcome measure is the Inflammatory Bowel Disease Quality of Life Questionnaire. Secondary outcomes include other health-related questionnaires and biological indices. Statistical analysis will adhere to an intention-to-treat approach using linear mixed effect models. Ethical approval has been obtained from the University of Hertfordshire (cLMS/SF/UH/05240), and the trial has been registered as a clinical trial (NCT05486507). The trial findings will be disseminated through a peer-reviewed publication in a scientific journal.

Diet as an Optional Treatment in Adults With Inflammatory Bowel Disease: A Systematic Review of the Literature

While the exact cause of IBD is unknown, there are a number of factors that are thought to contribute to its development, including environmental and genetic factors. While exclusive enteral nutrition (EEN) is a promising therapy for Crohn's disease (CD), it is not yet considered a first-line treatment. Additionally, the efficacy of EEN compared to corticosteroid treatment is still being investigated. EEN is suggested as a first-line therapy by which guidelines and in which age groups, as it may differ in pediatric and adult recommendations. Another finding was that dietary changes involving an increase in anti-inflammatory foods and decreased intake of foods high in inflammatory compounds are linked to a beneficial outcome both metabolically and microbiologically in patients with ulcerative colitis (UC) in remission. For relevant medical literature, we examined PubMed/Medline, the Cochrane Library, and Google Scholar as examples of medical databases. The articles were identified, evaluated, and eligibility applied, and nine publications were found. The finished articles investigated the role of several diet alternatives for patients with IBD. Some others have shown that following a normal low-fat diet may be effective in reducing the occurrence of subclinical colitis. The EEN and partial enteral nutrition (PEN) indicated no significant differences between both regimens, but both had good outcomes during active IBD. Other strict diets, such as the specific carbohydrate diet (SCD) versus the Mediterranean diet (MD), demonstrate excellent outcomes in patients with IBD. Fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAP) dietary counseling improves gastrointestinal symptoms and quality of life in IBD patients. Based on the above, we concluded that more studies determining which component of the diet is not clear (proteins, carbs balanced) or diet types are required to establish a particular diet employed as a treatment intervention in these individuals.

The gut dysbiosis-cancer axis: illuminating novel insights and implications for clinical practice

The human intestinal microbiota, also known as the gut microbiota, comprises more than 100 trillion organisms, mainly bacteria. This number exceeds the host body cells by a factor of ten. The gastrointestinal tract, which houses 60%-80% of the host's immune cells, is one of the largest immune organs. It maintains systemic immune homeostasis in the face of constant bacterial challenges. The gut microbiota has evolved with the host, and its symbiotic state with the host's gut epithelium is a testament to this co-evolution. However, certain microbial subpopulations may expand during pathological interventions, disrupting the delicate species-level microbial equilibrium and triggering inflammation and tumorigenesis. This review highlights the impact of gut microbiota dysbiosis on the development and progression of certain types of cancers and discusses the potential for developing new therapeutic strategies against cancer by manipulating the gut microbiota. By interacting with the host microbiota, we may be able to enhance the effectiveness of anticancer therapies and open new avenues for improving patient outcomes.

Therapeutic effect of Lactobacillus plantarum JS19 on mice with dextran sulfate sodium induced acute and chronic ulcerative colitis

BACKGROUND

Ulcerative colitis is associated with intestinal inflammation and dysbiosis. Previous studies have shown that probiotics are potential agents for treatment of inflammatory bowel disease (IBD). Jiang-shui is a traditional fermented vegetable that is rich in lactic acid bacteria (LABs), but the preventive effect of LABs in jiang-shui on IBD is not yet fully understood.

RESULTS

We isolated 38 LAB strains from jiang-shui, and Lactobacillus plantarum JS19 exhibited the strongest antioxidant activity among them. Our data indicate that oral administration of L. plantarum JS19 significantly inhibited body weight loss, colon shortening and damage, and reduced the disease activity index score in the mice with dextran sulfate sodium (DSS)-induced colitis. In addition, L. plantarum JS19 also alleviated inflammatory responses and oxidative stress through reducing lipid peroxidation, tumor necrosis factor-α expression, and myeloperoxidase activity and enhancing the antioxidant enzyme activity. Importantly, L. plantarum JS19 significantly rebalanced DSS-induced dysbiosis of gut microbiota.

CONCLUSION

L. plantarum JS19 may be used as a potential probiotic to prevent IBD, particularly ulcerative colitis. © 2022 Society of Chemical Industry.

Effects of Pine Pollen Polysaccharides and Sulfated Polysaccharides on Ulcerative Colitis and Gut Flora in Mice

Polysaccharides are important biological macromolecules in all organisms, and have recently been studied as therapeutic agents for ulcerative colitis (UC). However, the effects of Pinus yunnanensis pollen polysaccharides on ulcerative colitis remains unknown. In this study, dextran sodium sulfate (DSS) was used to induce the UC model to investigate the effects of Pinus yunnanensis pollen polysaccharides (PPM60) and sulfated polysaccharides (SPPM60) on UC. We evaluated the improvement of polysaccharides on UC by analyzing the levels of intestinal cytokines, serum metabolites and metabolic pathways, intestinal flora species diversity, and beneficial and harmful bacteria. The results show that purified PPM60 and its sulfated form SPPM60 effectively alleviated the disease progression of weight loss, colon shortening and intestinal injury in UC mice. On the intestinal immunity level, PPM60 and SPPM60 increased the levels of anti-inflammatory cytokines (IL-2, IL-10, and IL-13) and decreased the levels of proinflammatory cytokines (IL-1β, IL-6, and TNF-α). On the serum metabolism level, PPM60 and SPPM60 mainly regulated the abnormal serum metabolism of UC mice by regulating the energy-related and lipid-related metabolism pathways, respectively. On the intestinal flora level, PPM60 and SPPM60 reduced the abundance of harmful bacteria (such as Akkermansia and Aerococcus) and induced the abundance of beneficial bacteria (such as lactobacillus). In summary, this study is the first to evaluate the effects of PPM60 and SPPM60 on UC from the joint perspectives of intestinal immunity, serum metabolomics, and intestinal flora, which may provide an experimental basis for plant polysaccharides as an adjuvant clinical treatment of UC.

Disruption of the Intestinal Mucosal Barrier Induced by High Fructose and Restraint Stress Is Regulated by the Intestinal Microbiota and Microbiota Metabolites

Environmental (restraint stress) and dietary (high fructose) factors are key triggers for flares of inflammatory bowel disease; however, the mechanisms involved in this phenomenon are not fully elucidated. This study aimed to investigate the mechanisms by which restraint stress and high fructose damage the intestinal mucosal immune barrier. The feces of C57BL/6J mice were subjected to 16S rRNA and untargeted metabolome sequencing, and the intestinal histological structure was analyzed by immunohistochemistry and immunofluorescence staining. The mRNA and protein levels of the intestinal protein were analyzed by reverse transcription-PCR (RT-PCR), Western blotting, and enzyme-linked immunosorbent assay (ELISA). The metabolites of the microbiota were tested in vitro, and Akkermansia muciniphila was used for colonization in vivo. Dietary fructose exacerbated the development of restraint stress, with an extensive change in the composition of the gut microbiota and microbial metabolites. The disturbance of the microbiota composition led to an increase in the abundance of histamine and a decrease in the abundance of taurine, which inhibited the expression of tight junction and MUC2 proteins, destroyed the function of NLRP6, and reduced intestinal autophagy level; this in turn disrupted the function of colonic goblet cells to secrete mucus, leading to defects in the intestinal mucosal barrier, which ultimately codrives colon autoinflammation. However, A. muciniphila supplementation counteracted damage to the intestinal mucosal barrier by high fructose and restraint stress. Therefore, the gut microbiota and microbiota metabolites play an important role in maintaining microenvironment homeostasis of the intestinal mucosal barrier. IMPORTANCE A high-fructose diet aggravated restraint stress-induced changes in the composition of the intestinal microbiome, in which the abundance of A. muciniphila was significantly increased. The high-fructose diet exacerbated restraint stress-induced the changes in the composition of the microbial metabolites, with taurine abundance being downregulated and histamine abundance upregulated. High fructose and restraint stress induced colonic mucosal immune barrier damage, possibly due to changes in the abundance of the microbial metabolites taurine and histamine. Colonization with A. muciniphila stimulated the expression of the NLRP6 inflammasome and activated autophagy in goblet cells, thereby producing more new mucins, which could protect the intestinal mucosal barrier.

Precision medicine and drug optimization in adult inflammatory bowel disease patients

Inflammatory bowel diseases (IBD) encompass two main entities including ulcerative colitis and Crohn's disease. Although having a common global pathophysiological mechanism, IBD patients are characterized by a significant interindividual heterogeneity and may differ by their disease type, disease locations, disease behaviours, disease manifestations, disease course as well as treatment needs. Indeed, although the therapeutic armamentarium for these diseases has expanded rapidly in recent years, a proportion of patients remains with a suboptimal response to medical treatment due to primary non-response, secondary loss of response or intolerance to currently available drugs. Identifying, prior to treatment initiation, which patients are likely to respond to a specific drug would improve the disease management, avoid unnecessary side effects and reduce the healthcare expenses. Precision medicine classifies individuals into subpopulations according to clinical and molecular characteristics with the objective to tailor preventative and therapeutic interventions to the characteristics of each patient. Interventions would thus be performed only on those who will benefit, sparing side effects and expense for those who will not. This review aims to summarize clinical factors, biomarkers (genetic, transcriptomic, proteomic, metabolic, radiomic or from the microbiota) and tools that could predict disease progression to guide towards a step-up or top-down strategy. Predictive factors of response or non-response to treatment will then be reviewed, followed by a discussion about the optimal dose of drug required for patients. The time at which these treatments should be administered (or rather can be stopped in case of a deep remission or in the aftermath of a surgery) will also be addressed. IBD remain biologically complex, with multifactorial etiopathology, clinical heterogeneity as well as temporal and therapeutic variabilities, which makes precision medicine especially challenging in this area. Although applied for many years in oncology, it remains an unmet medical need in IBD.

The spring-like effect of microRNA-31 in balancing inflammatory and regenerative responses in colitis

Inflammatory bowel diseases (IBDs) are chronic inflammatory disorders caused by the disruption of immune tolerance to the gut microbiota. MicroRNA-31 (MIR31) has been proven to be up-regulated in intestinal tissues from patients with IBDs and colitis-associated neoplasias. While the functional role of MIR31 in colitis and related diseases remain elusive. Combining mathematical modeling and experimental analysis, we systematically explored the regulatory mechanism of MIR31 in inflammatory and epithelial regeneration responses in colitis. Level of MIR31 presents an "adaptation" behavior in dextran sulfate sodium (DSS)-induced colitis, and the similar behavior is also observed for the key cytokines of p65 and STAT3. Simulation analysis predicts MIR31 suppresses the activation of p65 and STAT3 but accelerates the recovery of epithelia in colitis, which are validated by our experimental observations. Further analysis reveals that the number of proliferative epithelial cells, which characterizes the inflammatory process and the recovery of epithelia in colitis, is mainly determined by the inhibition of MIR31 on IL17RA. MIR31 promotes epithelial regeneration in low levels of DSS-induced colitis but inhibits inflammation with high DSS levels, which is dominated by the competition for MIR31 to either inhibit inflammation or promote epithelial regeneration by binding to different targets. The binding probability determines the functional transformation of MIR31, but the functional strength is determined by MIR31 levels. Thus, the role of MIR31 in the inflammatory response can be described as the "spring-like effect," where DSS, MIR31 action strength, and proliferative epithelial cell number are regarded as external force, intrinsic spring force, and spring length, respectively. Overall, our study uncovers the vital roles of MIR31 in balancing inflammation and the recovery of epithelia in colitis, providing potential clues for the development of therapeutic targets in drug design.

Jatrorrhizine alleviates ulcerative colitis via regulating gut microbiota and NOS2 expression

Background

The natural protoberberine jatrorrhizine (JA) is reported to have several medicinal properties and a significant effect on the gut microbiota of mice. The regulation of gut microbiota is generally known to play an important role in the intestinal mucosal immune response to ulcerative colitis (UC). However, whether JA can be used in the treatment of UC is still unclear. Our study aimed to investigate the underlying therapeutic effects and mechanisms of JA in treating colitis.

Results

Compared with the DSS-induced colitis model group, the JA + DSS treated group had more significant improvements in weight loss, disease activity index score, colon length shortening, and pathological inflammation. 16s rRNA sequencing analysis showed that JA treatment protected colitis mice against DSS-induced disturbance of gut microbiota. At the phylum level, reductions in Deferribacteres and Proteobacteria were observed in the JA-treated group; At the genus level, the JA-treated group showed an increased relative abundance of Akkermansia and decreased abundance of Escherichia-Shigella, Desulfovibrio, Mucispirillum, etc. Network pharmacology was then used to screen out five drug-disease target genes (NOS2, ESR1, CALM1, CALM2, CALM3). Transcriptomics analysis further validated that the NOS2 expression was significantly reduced in colon tissue of JA-administered mice compared with DSS control mice. Additionally, analysis of correlation suggested that NOS2 expression was negatively correlated with the relative abundance of AKKermansia and positively correlated with Desulfovibrio, Rikenella.

Conclusion

JA alleviates ulcerative colitis via regulating gut microbiota and NOS2 expression.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13099-022-00514-z.

Role of a probiotic strain in the modulation of gut microbiota and cytokines in inflammatory bowel disease

OBJECTIVE

To assess the effect of a probiotic strain Bacillus clausii UBBC-07 on gut microbiota and cytokines in IBD patients.

METHOD

Patients were randomly allocated to either placebo or probiotic Bacillus clausii UBBC-07 for four weeks along with the standard medical treatment (SMT). Enrolled patients were evaluated before and after intervention for presence of the given probiotic, change in gut microbiota, change in serum cytokines, serotonin and dopamine, symptoms of disease, physical, behavioral and psychological parameters.

RESULTS

Probiotic strain Bacillus clausii UBBC-07 showed good survival in IBD patients in the treatment group (p < 0.01) without any reported adverse event. Metagenomic analysis showed that the given probiotic strain was able to modulate the gut microbiota in treated group. Phylum Firmicutes was increased and phylum Bacteroidetes was decreased in the probiotic treated group. A significant increase was observed in the abundance of anaerobic bacterial genera Lactobacillus, Bifidobacterium and Faecalibacterium in the probiotic treated group (p < 0.01) as compared to placebo group. Significant increase was observed in IL-10 (p < 0.05) and variable decrease in the secretion of IL-1β, TNF- α, IL-6, IL -17 and IL -23 in probiotic treated group. In the treatment group a significant decrease in the symptoms of IBD and improvement in the psychological parameter to various degrees was noted.

CONCLUSION

These results indicated that probiotic strain B clausii UBBC-07 affected the gut microbiota and cytokine secretion and shown efficacy in IBD patients.

Electrical neuromodulation therapy for inflammatory bowel disease

Inflammatory bowel disease (IBD) is an inflammatory disease of the gastrointestinal (GI) tract. It has financial and quality of life impact on patients. Although there has been a significant advancement in treatments, a considerable number of patients do not respond to it or have severe side effects. Therapeutic approaches such as electrical neuromodulation are being investigated to provide alternate options. Although bioelectric neuromodulation technology has evolved significantly in the last decade, sacral nerve stimulation (SNS) for fecal incontinence remains the only neuromodulation protocol commonly utilized use for GI disease. For IBD treatment, several electrical neuromodulation techniques have been studied, such as vagus NS, SNS, and tibial NS. Several animal and clinical experiments were conducted to study the effectiveness, with encouraging results. The precise underlying mechanisms of action for electrical neuromodulation are unclear, but this modality appears to be promising. Randomized control trials are required to investigate the efficacy of intrinsic processes. In this review, we will discuss the electrical modulation therapy for the IBD and the data pertaining to it.

Comparative study of different liquid diets for dairy calves and the impact on performance and the bacterial community during diarrhea

The liquid diet composition can affect dairy calves' performance and diarrhea incidence. The effect of three liquid diets on performance, incidence of diarrhea, and microbial community during diarrhea occurrence in dairy calves were evaluated. At birth, 35 dairy calves (20 male and 15 female) were randomly assigned to one of three treatments-refrigerated whole milk (WM), acidified whole milk (AWM), and milk replacer (MR). Intake, fecal score, and rectal temperature were evaluated daily, and performance and blood parameters were evaluated weekly during the preweaning period. Fecal samples from diarrheic calves were collected, and one initial and one final sample for each episode were selected. The bacterial community was assessed by sequencing the V3-V4 region of the 16S rRNA gene on the Illumina MiSeq platform and analyzed using the DADA2 pipeline. Calves fed WM had higher body weight at weaning, average daily gain, body measurements, and concentration of blood metabolites. The AWM-fed calves had a lower rectal temperature and fever days. Moreover, the MR-fed calves had lower beta-hydroxybutyrate concentration and a higher incidence of diarrhea. The fecal bacterial community of diarrheic calves showed dissimilarity among the AWM and the other treatments. At the compositional level, we observed a higher abundance of Fusobacterium and Ruminococcus genera (AWM), Prevotella (WM), and Lactobacillus (MR). In the AWM and MR diarrheic calves' feces, we also observed some beneficial bacterial genera. The performance and incidence of diarrhea of dairy calves were influenced by the liquid diet consumed and the bacterial composition of diarrhea.

Features of the gut prokaryotic virome of Japanese patients with Crohn's disease

BACKGROUND/AIMS

The gut virome is mainly composed of bacteriophages and influences gut homeostasis and pathogenic conditions. In this study, we analyzed the gut prokaryotic virome in Japanese patients with Crohn's disease (CD).

MATERIALS/METHODS

We collected 19 fecal samples from CD patients and 16 samples from healthy controls. The gut bacteriome was analyzed by 16S rRNA gene sequencing and the virome was profiled by shotgun metagenomic sequencing.

RESULTS

Despite no differences in richness and evenness, there was a significant difference in the overall structure of the gut virome between CD patients and controls (P = 0.013). CrAssphage and Staphylococcus virus, belonging to the order Caudovirales, were dominant in the gut virome of controls and CD patients. The abundance of crAssphage was significantly greater in CD patients than controls (P = 0.021). Lactococcus, Enterococcus and Lactobacillus phages were present only in CD patients, while Xanthomonas and Escherichia phages were unique to the controls. In the gut bacteriome of CD patients, richness and evenness were significantly lower, and a significant difference in the overall structure was observed between groups (P = 0.014). The gut bacteriome of CD patients was characterized by a decrease of the genera Faecalibacterium, Roseburia, and Ruminococcus and an increase of the family Enterobacteriaceae. There were more significant correlations between viruses and bacteria in CD patients than controls.

CONCLUSIONS

The gut virome of CD patients was distinct from that of healthy controls in a Japanese population. An altered gut virome may be one of the factors associated with the bacterial dysbiosis of CD.

Fecal Microbial Changes in Response to Finishing Pigs Directly Fed With Fermented Feed

The present study investigated the effects of fermented complete feed (FCF) on fecal microbial composition during the grower-finisher period. A total of 20 pigs (Duroc × Landrace × Yorkshire, 48.74± 1.49 kg) were divided randomly into two groups: the CN group (pigs fed with a basal diet) and the FCF group (pigs fed with FCF). After a 60-day trial period, 3 pigs with middle-weight from each treatment were selected for fecal sampling and fecal microbiota analysis. The results showed that the FCF significantly increased operational taxonomic units (OUT) numbers, alpha diversity (Simpson index and Shannon index), and beta diversity, which means that FCF increased the fecal microbiota diversity. At the phylum level, the abundance of Tenericutes, Spirochaetae, Verrucomicrobia, and Cyanobacteria were changed in pigs fed with FCF; and at the genus level, the abundance of Christensenellaceae_R-7_group, Treponema_2, Ruminococcaceae_UCG-005, Prevotellaceae_UCG-003, Phascolarctobacterium, Roseburia, and Prevotella_9 were changed in pigs fed with FCF. The linear discriminant analysis effect size (LEfSe) analysis showed that Roseburia and Prevotella_9 genera were increased, while Tenericutes phyla and Streptococcus, Christensenellaceae_R-7_group, and Lactobacillus genera were decreased in the FCF group compared to the CN group. Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) results predicted that the relative abundance of infectious diseases: parasitic associated genes, xenobiotics biodegradation, and metabolism-associated genes were significantly reduced in the FCF group when compared with the CN group, and the relative abundance of signal transduction associated genes, amino acid metabolism-related genes, and replication and repair associated genes were significantly higher in the FCF group when compared with the CN group. In addition, the relative abundance of transport and catabolism-associated genes, membrane transport-associated genes, and biosynthesis of other secondary metabolite-associated genes tended to be higher in the FCF group when compared with the CN group; and the relative abundance of immune diseases associated genes tended to be lower in the FCF group when compared with the CN group. In conclusion, the FCF influenced the alpha and beta diversity of the fecal microbiota of pigs.

Interleukin-37 exacerbates experimental colitis in an intestinal microbiome-dependent fashion

Background: Inflammatory bowel disease (IBD) involves complicated crosstalk between host immunity and the gut microbiome, whereas the mechanics of how they govern intestinal inflammation remain poorly understood. In this study, we investigated the contribution of environmental factors to shaping gut microbiota composition in colitis mice that were transgenic for human IL-37, a natural anti-inflammatory cytokine possessing pathogenic and protective functions related to microbiota alterations. Methods: Mice transgenic expressing human IL-37 (IL-37tg) were housed under conventional and specific pathogen-free (SPF) conditions to develop a mouse model of dextran sulfate sodium (DSS)-induced colitis. 16S ribosomal RNA sequencing was used for analyzing fecal microbial communities. The efficacy of microbiota in the development of colitis in IL-37tg mice was investigated after antibiotic treatment and fecal microbiota transplantation (FMT). The mechanism by which IL-37 worsened colitis was studied by evaluating intestinal epithelial barrier function, immune cell infiltration, the expression of diverse cytokines and chemokines, as well as activated signaling pathways. Results: We found that IL-37 overexpression aggravated DSS-induced colitis in conventional mice but protected against colitis in SPF mice. These conflicting results from IL-37tg colitis mice are ascribed to a dysbiosis of the gut microbiota in which detrimental bacteria increased in IL-37tg conventional mice. We further identified that the outcome of IL-37-caused colon inflammation is strongly related to intestinal epithelial barrier impairment caused by pathogenic bacteria, neutrophils, and NK cells recruitment in colon lamina propria and mesenteric lymph node to enhance inflammatory responses in IL-37tg conventional mice. Conclusions: The immunoregulatory properties of IL-37 are detrimental in the face of dysbiosis of the intestinal microbiota, which contributes to exacerbated IBD occurrences that are uncontrollable by the immune system, suggesting that depleting gut pathogenic bacteria or maintaining intestinal microbial and immune homeostasis could be a promising therapeutic strategy for IBD.

Microbiota, not host origin drives ex vivo intestinal epithelial responses

Microbial dysbiosis is an established finding in patients with inflammatory bowel disease (IBD), but host-microbial interactions are poorly understood. We aimed to unravel the effect of microbiota exposure on intestinal epithelial cells. Confluent Transwell® organoid monolayers of eight UC patients and eight non-IBD controls were co-cultured for six hours with microbiota (3x10⁸ cells) of UC patients or a healthy volunteer (HV), in the presence or absence of an inflammatory cytokine mix. Transepithelial electrical resistance (TEER), fluorescein isothiocyanate (FITC) dextran measurements, and RNA sequencing were performed on epithelial cells, and 16S rRNA sequencing on microbiota samples before and after co-culture. Transcriptomic response following microbiota exposure was not different between epithelial cells from UC patients or non-IBD controls. Following UC microbiota exposure, but not HV microbiota, a strong decrease in epithelial barrier integrity was observed in both UC and HV epithelial cells by TEER and FITC dextran measurements. Exposure of inflamed epithelium to UC microbiota induced transcriptomic stress pathways including activation of EGR1, MAPK and JAK/STAT signaling, as well as AP-1 family and FOSL transcripts. Stress responses after HV microbiota stimulation were milder. We conclude that not the epithelial cell origin (UC versus non-IBD) but the microbial donor drives transcriptomic responses, as exposure to UC microbiota was sufficient to induce stress responses in all epithelial cells. Further research on therapies to restore the microbial balance, to remove the constant trigger of dysbiosis, is required.

Prebiotics and the Human Gut Microbiota: From Breakdown Mechanisms to the Impact on Metabolic Health

The colon harbours a dynamic and complex community of microorganisms, collectively known as the gut microbiota, which constitutes the densest microbial ecosystem in the human body. These commensal gut microbes play a key role in human health and diseases, revealing the strong potential of fine-tuning the gut microbiota to confer health benefits. In this context, dietary strategies targeting gut microbes to modulate the composition and metabolic function of microbial communities are of increasing interest. One such dietary strategy is the use of prebiotics, which are defined as substrates that are selectively utilised by host microorganisms to confer a health benefit. A better understanding of the metabolic pathways involved in the breakdown of prebiotics is essential to improve these nutritional strategies. In this review, we will present the concept of prebiotics, and focus on the main sources and nature of these components, which are mainly non-digestible polysaccharides. We will review the breakdown mechanisms of complex carbohydrates by the intestinal microbiota and present short-chain fatty acids (SCFAs) as key molecules mediating the dialogue between the intestinal microbiota and the host. Finally, we will review human studies exploring the potential of prebiotics in metabolic diseases, revealing the personalised responses to prebiotic ingestion. In conclusion, we hope that this review will be of interest to identify mechanistic factors for the optimization of prebiotic-based strategies.

Lactobacillus acidophilus and HKL Suspension Alleviates Ulcerative Colitis in Rats by Regulating Gut Microbiota, Suppressing TLR9, and Promoting Metabolism

Ulcerative colitis (UC) is a chronic non-specific inflammatory bowel disease with complex pathogenesis. The intestinal flora disturbance affects the homeostasis of the intestinal environment, leading to metabolic imbalance and immune abnormalities of the host, contributing to the perpetuation of intestinal inflammation. We suggest that the combination of anti-inflammatory therapy and the regulation of intestinal flora balance may help in the treatment process. Previously, we used a combination treatment consisting of Lactobacillus acidophilus (Lac) and Chinese medicine Huan Kui Le (HKL) suspension in a UC rat model, where the combined intervention was more effective than either treatment alone. Herein, the mechanism of action of this combined treatment has been investigated using 16S rRNA sequencing, immunohistochemistry, and ELISA methods in the colon, and untargeted metabolomics profiling in serum. Colon protein expression levels of IL-13 and TGF-β were upregulated, whereas those of TLR9 and TLR4 were downregulated, consistent with an anti-inflammatory effect. In addition, gut microbiota structure changed, shown by a decrease in opportunistic pathogens correlated with intestinal inflammation, such as Klebsiella and Escherichia-Shigella, and an increase in beneficial bacteria such as Bifidobacterium. The latter correlated positively with IL-13 and TGF-β and negatively with IFN-γ. Finally, this treatment alleviated the disruption of the metabolic profile observed in UC rats by increasing short-chain fatty acid (SCFA)–producing bacteria in the colonic epithelium. This combination treatment also affected the metabolism of lactic acid, creatine, and glycine and inhibited the growth of Klebsiella. Overall, we suggest that treatment combining probiotics and traditional Chinese medicine is a novel strategy beneficial in UC that acts by modulating gut microbiota and its metabolites, TLR9, and cytokines in different pathways.

Inflammatory bowel disease biomarkers of human gut microbiota selected via different feature selection methods

The tremendous boost in next generation sequencing and in the "omics" technologies makes it possible to characterize the human gut microbiome-the collective genomes of the microbial community that reside in our gastrointestinal tract. Although some of these microorganisms are considered to be essential regulators of our immune system, the alteration of the complexity and eubiotic state of microbiota might promote autoimmune and inflammatory disorders such as diabetes, rheumatoid arthritis, Inflammatory bowel diseases (IBD), obesity, and carcinogenesis. IBD, comprising Crohn's disease and ulcerative colitis, is a gut-related, multifactorial disease with an unknown etiology. IBD presents defects in the detection and control of the gut microbiota, associated with unbalanced immune reactions, genetic mutations that confer susceptibility to the disease, and complex environmental conditions such as westernized lifestyle. Although some existing studies attempt to unveil the composition and functional capacity of the gut microbiome in relation to IBD diseases, a comprehensive picture of the gut microbiome in IBD patients is far from being complete. Due to the complexity of metagenomic studies, the applications of the state-of-the-art machine learning techniques became popular to address a wide range of questions in the field of metagenomic data analysis. In this regard, using IBD associated metagenomics dataset, this study utilizes both supervised and unsupervised machine learning algorithms, (i) to generate a classification model that aids IBD diagnosis, (ii) to discover IBD-associated biomarkers, (iii) to discover subgroups of IBD patients using k-means and hierarchical clustering approaches. To deal with the high dimensionality of features, we applied robust feature selection algorithms such as Conditional Mutual Information Maximization (CMIM), Fast Correlation Based Filter (FCBF), min redundancy max relevance (mRMR), Select K Best (SKB), Information Gain (IG) and Extreme Gradient Boosting (XGBoost). In our experiments with 100-fold Monte Carlo cross-validation (MCCV), XGBoost, IG, and SKB methods showed a considerable effect in terms of minimizing the microbiota used for the diagnosis of IBD and thus reducing the cost and time. We observed that compared to Decision Tree, Support Vector Machine, Logitboost, Adaboost, and stacking ensemble classifiers, our Random Forest classifier resulted in better performance measures for the classification of IBD. Our findings revealed potential microbiome-mediated mechanisms of IBD and these findings might be useful for the development of microbiome-based diagnostics.

Association between intestinal microbiome and inflammatory bowel disease: insights from bibliometric analysis

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Intestinal microbiota has been increasingly studied in the field of IBD over the last 20 years.

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The gut microbiome, metabolites, and their corresponding host signaling pathways are highly associated with IBD.

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Probiotics may relieve IBD as a complementary therapy.

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The pathogenesis and treatment strategies of IBD need to be further studied.

The gut microbiome is highly linked to inflammatory bowel disease (IBD). A total of 3890 publications related to the two terms from 2000 to 2020 were extracted from the Web of Science Core Collection to study the association from a bibliometric perspective. Publications on this topic have grown rapidly since 2008. The United States and Harvard University are the country and institution with the largest number of publications, respectively. Inflammatory Bowel Diseases is the most productive journal with 211 published articles. The most influential journal in this field is Gut with 13,359 citations. The co-citation analysis of references showed that the IBD-related topics with the highest focus are “gut microbiota,” “metagenomics,” “bacterial community,” “fecal microbiota transplantation,” “probiotics,” and “colitis-associated colorectal cancer.” Keyword cluster and keyword burst analyses showed that “gut microbiota,” “metagenomics,” and “fecal microbiota transplantation” are currently the most researched topics in the field of IBD. The literature in this field is mainly distributed between alterations of the intestinal microbiota, microbial metabolites, and related host signaling pathways. Probiotic treatment also frequently appears in literature. This bibliometric analysis can guide future research and promote the development of the field of gut microbiome and IBD.

Effect of Fufang Huangqi Decoction on the Gut Microbiota in Patients With Class I or II Myasthenia Gravis

Objective

To investigate the effect of Fufang Huangqi Decoction on the gut microbiota in patients with class I or II myasthenia gravis (MG) and to explore the correlation between gut microbiota and MG (registration number, ChiCTR2100048367; registration website, http://www.chictr.org.cn/listbycreater.aspx; NCBI: SRP338707).

Methods

In this study, microbial community composition and diversity analyses were carried out on fecal specimens from MG patients who did not take Fufang Huangqi Decoction (control group, n = 8) and those who took Fufang Huangqi Decoction and achieved remarkable alleviation of symptoms (medication group, n = 8). The abundance, diversity within and between habitats, taxonomic differences and corresponding discrimination markers of gut microbiota in the control group and medicated group were assessed.

Results

Compared with the control group, the medicated group showed a significantly decreased abundance of Bacteroidetes (P < 0.05) and significantly increased abundance of Actinobacteria at the phylum level, a significantly decreased abundance of Bacteroidaceae (P < 0.05) and significantly increased abundance of Bifidobacteriaceae at the family level and a significantly decreased abundance of Blautia and Bacteroides (P < 0.05) and significantly increased abundance of Bifidobacterium, Lactobacillus and Roseburia at the genus level. Compared to the control group, the medicated group had decreased abundance, diversity, and genetic diversity of the communities and increased coverage, but the differences were not significant (P > 0.05); the markers that differed significantly between communities at the genus level and influenced the differences between groups were Blautia, Bacteroides, Bifidobacterium and Lactobacillus.

Conclusions

MG patients have obvious gut microbiota-associated metabolic disorders. Fufang Huangqi Decoction regulates the gut microbiota in patients with class I or II MG by reducing the abundance of Blautia and Bacteroides and increasing the abundance of Bifidobacterium and Lactobacillus. The correlation between gut microbiota and MG may be related to cell-mediated immunity.

Prediction of Inflammatory Bowel Disease Course Based on Fecal Scent

The early prediction of changes in disease state allows timely treatment of patients with inflammatory bowel disease (IBD) to be performed, which improves disease outcome. The aim of this pilot study is to explore the potential of fecal volatile organic compound (VOC) profiles to predict disease course. In this prospective cohort, IBD patients were asked to collect two fecal samples and fill in a questionnaire at set intervals. Biochemically, active disease was defined by FCP ≥ 250 mg/g and remission was defined by FCP < 100 mg/g. Clinically, active disease was defined by a Harvey Bradshaw Index (HBI) ≥ 5 for Crohn’s disease or by a Simple Clinical Colitis Activity Index (SCCAI) ≥ 3 for ulcerative colitis. Clinical remission was defined by an HBI < 4 or SCCAI ≤ 2. Fecal VOC profiles were measured using gas chromatography-ion mobility spectrometry (GC-IMS). The fecal samples collected first were included for VOC analysis to predict disease state at the following collection. A total of 182 subsequently collected samples met the disease-state criteria. The fecal VOC profiles of samples displaying low FCP levels at the first measurements differed between patients preceding exacerbation versus those who remained in remission (AUC 0.75; p < 0.01). Samples with FCP levels at the first time point displayed different VOC profiles in patients preceding remission compared with those whose disease remained active (AUC 0.86; p < 0.01). Based on disease activity scores, there were no significant differences in any of the comparisons. Alterations in fecal VOC profiles preceding changes in FCP levels may be useful to detect disease-course alterations at an early stage. This could lead to earlier treatment, decreased numbers of complications, surgery and hospital admission.

Exploration of the correlation between intestinal flora and Escherichia coli peritoneal dialysis-related peritonitis

BACKGROUND

Escherichia coli peritonitis (EP) is a serious complication of peritoneal dialysis (PD). Gut microbiota alterations occur in end-stage renal disease (ESRD) patients. The relationship between the gut microbiota and PD-related peritonitis is still poorly understood. It is unclear whether the intestinal flora is involved in the pathogenesis of EP.

METHODS

We collected fecal samples from EP patients and normal group (NG) PD patients. 16S rRNA sequencing was used to analyze the gut microbiota of EP and NG patients. The demographic data and clinical indicators of all patients were collected.

RESULTS

Six EP patients and 28 NG patients were recruited for this study. The analysis of fecal community diversity with 16S rDNA sequencing showed an obvious change in the microbial structure of EP patients, where Bacteroidetes and Synergistetes were upregulated at different levels, while Bacilli and Lactobacillus were downregulated at different levels compared to the NG group. Additionally, decreased gene function associated with metabolic pathways was observed in EP patients.

CONCLUSIONS

The altered composition of the gut microbiota in EP patients provided deeper insights into the pathogenesis of EP, and these biomarkers might be established as potential therapeutic targets that deserve further exploration.

Gut microbiota imbalance mediates intestinal barrier damage in high-altitude exposed mice

The environmental conditions in high-altitude areas can induce gastrointestinal disorders and changes in gut microbiota. The gut microbiota is closely related to a variety of gastrointestinal diseases, although the underlying pathogenic mechanisms are not well-identified. The present study aimed to investigate the regulatory effect of high altitude on intestinal dysfunction via gut microbiota disturbance. Forty C57BL/6J mice were divided into four groups: one plain control group (CON) and three high-altitude exposure groups (HAE) (altitude: 4000 m a.s.l.; oxygen content: 12.7%; 1-, 2- and 4-week exposure). Another set of 40 mice was divided into two CON and two HAE subgroups. Antibiotic cocktails were administered to one CON and HAE groups and autoclaved water was administered to the second CON and HAE groups for 4 weeks, respectively. In the fecal microbiota transplantation experiment, there were four transplantation groups, which received, respectively: phosphate-buffered saline for 2 weeks, feces from CON for 2 weeks, feces from HAE-4W for 2 weeks, and HAE-4W for 4 weeks. Hematoxylin and eosin staining, periodic acid-Schiff staining, a terminal deoxynucleotidyl transferase dUTP nick end labeling assay and a quantitative reverse transcriptase-polymerase chain reaction were applied to detect changes in intestinal cellular structure, morphology, apoptosis and intestinal inflammatory response. Fecal microbiota was analyzed using 16S rDNA amplicon sequencing. A high-altitude environment changed the ecological balance of gut microbiota in mice and caused damage to the intestinal structure and mucosal barrier. Interestingly, similar damage, which was inhibited by antibiotic cocktails at high altitude, was observed in mice transplanted with fecal microbiota from HAE. A high-altitude environment contributes to dyshomeostasis of gut microbiota, thereby impairing the intestinal mucosal barrier, eventually inducing and exacerbating intestinal damage.

The nonneuronal cholinergic system in the colon: A comprehensive review

Acetylcholine (ACh) is found not only in cholinergic nerve termini but also in the nonneuronal cholinergic system (NNCS). ACh is released from cholinergic nerves by vesicular ACh transporter (VAChT), but ACh release from the NNCS is mediated by organic cation transporter (OCT). Recent studies have suggested that components of the NNCS are located in intestinal epithelial cells (IECs), crypt-villus organoids, immune cells, intestinal stem cells (ISCs), and vascular endothelial cells (VECs). When ACh enters the interstitial space, its self-modulation or effects on adjacent tissues are part of the range of its biological functions. This review focuses on the current understanding of the mechanisms of ACh synthesis and release in the NNCS. Furthermore, studies on ACh functions in colonic disorders suggest that ACh from the NNCS contributes to immune regulation, IEC and VEC repair, ISC differentiation, colonic movement, and colonic tumor development. As indicated by the features of some colonic disorders, ACh and the NNCS have positive and negative effects on these disorders. Furthermore, the NNCS is located in multiple colonic organs, and the specific effects and cross-talk involving ACh from the NNCS in different colonic tissues are explored.

The Communication Between Intestinal Microbiota and Ulcerative Colitis: An Exploration of Pathogenesis, Animal Models, and Potential Therapeutic Strategies

Ulcerative Colitis (UC) is a chronic inflammatory bowel disease. The prolonged course of UC and the lack of effective treatment management make it difficult to cure, affecting the health and life safety of patients. Although UC has received more attention, the etiology and pathogenesis of UC are still unclear. Therefore, it is urgent to establish an updated and comprehensive understanding of UC and explore effective treatment strategies. Notably, sufficient evidence shows that the intestinal microbiota plays an important role in the pathogenesis of UC, and the treating method aimed at improving the balance of the intestinal microbiota exhibits a therapeutic potential for UC. This article reviews the relationship between the genetic, immunological and microbial risk factors with UC. At the same time, the UC animal models related to intestinal microbiota dysbiosis induced by chemical drugs were evaluated. Finally, the potential value of the therapeutic strategies for restoring intestinal microbial homeostasis and treating UC were also investigated. Comprehensively, this study may help to carry out preclinical research, treatment theory and methods, and health management strategy of UC, and provide some theoretical basis for TCM in the treatment of UC.

The role of enteric dysbacteriosis and modulation of gut microbiota in the treatment of inflammatory bowel disease

The incidence of inflammatory bowel disease (IBD) is globally increasing. This disorder seriously affects the quality of life in patients. Interestingly, studies have detected that the intestinal flora imbalance is a critical factor in the progression of IBD. One potential treatment strategy for IBD involves regulating the composition and function of the intestinal flora. To date, a multitude of experiments have confirmed the relationship between intestinal flora, immune regulation, and anti-inflammation. The intestinal flora can reduce intestinal inflammation by regulating immunity and increasing the secretion of metabolic short-chain fatty acids. In this review, we discuss the composition and function of the intestinal flora, the relationship between the intestinal flora and the host, the role of intestinal flora disorders in IBD, and the progress in IBD treatment. Combining the regulation of the intestinal flora with probiotics treatment is considered a promising strategy for substantially improving the treatment of IBD.

Mikrobiota jelitowa a leki. Interakcje wpływające na skuteczność i bezpieczeństwo farmakoterapii

Mikrobiota jelitowa stanowi nieodłączny element organizmu umożliwiający jego prawidłowe funkcjonowanie. Dzięki mikroorganizmom jelitowym możliwa jest stymulacja układu odpornościowego, synteza witamin czy poprawa wchłaniania składników odżywczych. Jednak jej aktywność może również niekorzystnie działać na organizm, m.in. z powodu przetwarzania treści jelitowej. Opisywana w artykule interakcja mikrobiota–lek uwzględnia pozytywny i negatywny wpływ mikroorganizmów jelitowych na farmakoterapię poprzez bezpośrednie i pośrednie oddziaływanie na lek w organizmie. Ze względu na to, że mikrobiom stanowi nieodłączny element organizmu, ingerencja nawet w jego niewielką część może doprowadzić do wystąpienia daleko idących, czasami niespodziewanych skutków. Stąd w celu poprawy skuteczności i bezpieczeństwa farmakoterapii konieczne jest wyjaśnienie mechanizmów oddziaływania mikrobioty na lek w organizmie.

W artykule podsumowano obecną wiedzę na temat biologicznej aktywności mikrobioty jelitowej, a zwłaszcza oddziaływań mikrobiota–leki determinujących skuteczność i bezpieczeństwo farmakoterapii. Wyszukiwanie przeprowadzono we wrześniu 2020 r. w bazach danych PubMed, Scopus, Web of Science, Cochrane Library i powszechnie dostępnej literaturze z użyciem terminów: „mikrobiota jelitowa”, „mikrobiom”, „metabolizm leku”, „interakcje mikrobiota–lek”. W artykule omówiono interakcje między mikrobiotą a lekami m.in. z grupy antybiotyków, inhibitorów pompy protonowej, sulfonamidów, pochodnych kwasu 5-aminosalicylowego, niesteroidowych leków przeciwzapalnych, przeciwnowotworowych, statyn czy metforminą.

Emodin Improves Intestinal Health and Immunity through Modulation of Gut Microbiota in Mice Infected by Pathogenic Escherichia coli O1

The effect of emodin on the intestinal mucosal barrier of a mouse E. coli O₁-induced diarrhea model was observed. Following successful establishment of a diarrhea model, the mice were treated with drugs for seven days. Intestinal lesions and the shape and the number of goblet cells were assessed via hematoxylin-eosin and periodic-acid-Schiff staining, while changes in inflammatory factors, ultrastructure of the small intestine, expression of MUC-2, and changes in the intestinal microbiota were analyzed via RT-PCR, electron microscopy, immunofluorescence, and 16S rRNA sequencing. Examination showed that emodin ameliorated pathological damage to the intestines of diarrheic mice. RT-PCR indicated that emodin reduced TNF-α, IL-β, IL-6, MPO, and COX-2 mRNA levels in duodenal tissues and increased the levels of sIgA and MUC-2 and the number of goblet cells. Microbiome analysis revealed that Escherichia coli O₁ reduced bacterial richness and altered the distribution pattern of bacterial communities at the phylum and order levels in cecum contents. Notably, pathogenic Clostridiales and Enterobacteriales were significantly increased in diarrheic mice. However, emodin reversed the trend. Thus, emodin protected against intestinal damage induced by E. coli O₁ and improved intestinal mucosal barrier function in mice by increasing the abundance of beneficial intestinal microbiota and inhibiting the abundance of harmful bacteria, thereby alleviating diarrhea.

Intestinal flora alterations in patients with ulcerative colitis and their association with inflammation

Ulcerative colitis (UC), which is a type of inflammatory bowel disease, is a chronic intestinal disorder of multifactorial etiology. Numerous studies have indicated an association between UC and intestinal bacteria. However, a limited number of studies regarding the expression of interleukin-17 (IL-17) and interleukin-23 (IL-23) in association with intestinal bacteria have been performed. The aim of the current study was to investigate the gut microbiota alterations in patients with UC, at a number of taxonomic levels, and their relationship with intestinal inflammation by analyzing the protein expression of IL-17 and IL-23. Specimens were collected from 10 healthy controls and 16 patients with UC. A histological examination was performed in colonic tissues, IL-17 and IL-23 protein expression was detected by immunohistochemistry, fecal samples were sequenced using 16S rDNA sequencing and bioinformatics analysis was performed. The UC group exhibited an increased histological score (P<0.01) and upregulated IL-17 and IL-23 expression (P<0.01). At the order level, the bacterial diversity of the UC group was decreased. β-diversity analyses, including principal component analysis, principal coordinate analysis and non-metric multidimensional scaling, demonstrated that the two groups of samples were separated into two taxonomic categories, as distinct variations were observed in the analysis of group differences (P=0.001). Regarding the differences in species composition between the groups, Enterococcus was indicated to be the species with the greatest difference in abundance compared with the healthy control group (P<0.01), followed by Lactobacillus (P<0.05), Escherichia-Shigella (P<0.05), Bifidobacterium and Bacteroides. In addition, the average optical density of IL-17 was positively correlated with the histological score (ρ=0.669; P=0.035), Enterococcus (r=0.843; P<0.001), Lactobacillus (r=0.737; P=0.001), Bifidobacterium (r=0.773; P<0.001) and Escherichia-Shigella (r=0.663; P=0.005), and the average optical density of IL-23 was positively correlated with the histological score (ρ=0.733; P=0.016), Enterococcus (r=0.771; P<0.001), Lactobacillus (r=0.566; P=0.022), Bifidobacterium (r=0.517; P=0.041) and Escherichia-Shigella (r=0.613; P=0.012). The results of the present study indicated that the intestinal microbiota of patients with UC differed from that of healthy controls at multiple taxonomic levels. The alterations of the intestinal microflora were closely associated with the degree of inflammation. The IL-23/IL-17 axis, as a key factor in the development of UC, maybe associated with the alterations of intestinal microflora. The interaction between intestinal microflora and the IL-23/IL-17 axis may serve an important role in the pathogenesis of UC.

Vitamin A supplementation ameliorates ulcerative colitis in gut microbiota-dependent manner

Ulcerative colitis (UC), is a chronic relapsing inflammatory condition of the gastrointestinal track. The purpose of this study is to explore whether Vitamin A (V_A) can treat UC and its mechanisms. A mouse model of UC was established using 3.0% (w/v) dextran sodium sulfate (DSS). V_A was used to treat UC by intragastric administration of 5000 international unit (IU) retinyl acetate. Fecal microbiota transplantation (FMT) was also used to treat the UC model mice to verify the effect of influenced gut microbiota. The content of short-chain fatty acids (SCFAs) in cecal contents was quantitatively detected by gas chromatography and mass spectrometry. V_A supplementation significantly ameliorated UC. 16S rRNA sequencing indicated that V_A-treated mice exhibited much more abundant gut microbial diversity and flora composition. Targeted metabolomics analysis manifested the increased production of SCFAs in V_A-treated mice. Gut microbiota depletion and FMT results confirmed the gut microbiota-dependent mechanism as that V_A relieved UC via regulating gut microbiota: increase in SCFA-producing genera and decrease in UC-related genera. The restore of intestinal barrier and the inhibition of inflammation were also found to contribute to the amelioration of UC by V_A. It was concluded that a V_A supplement was enough to cause a significant change in gut microbiota and amelioration of UC.

Landscapes and bacterial signatures of mucosa-associated intestinal microbiota in Chilean and Spanish patients with inflammatory bowel disease

Inflammatory bowel diseases (IBDs), which include ulcerative colitis (UC) and Crohn's disease (CD), cause chronic inflammation of the gut, affecting millions of people worldwide. IBDs have been frequently associated with an alteration of the gut microbiota, termed dysbiosis, which is generally characterized by an increase in abundance of Proteobacteria such as Escherichia coli, and a decrease in abundance of Firmicutes such as Faecalibacterium prausnitzii (an indicator of a healthy colonic microbiota). The mechanisms behind the development of IBDs and dysbiosis are incompletely understood. Using samples from colonic biopsies, we studied the mucosa-associated intestinal microbiota in Chilean and Spanish patients with IBD. In agreement with previous studies, microbiome comparison between IBD patients and non-IBD controls indicated that dysbiosis in these patients is characterized by an increase of pro-inflammatory bacteria (mostly Proteobacteria) and a decrease of commensal beneficial bacteria (mostly Firmicutes). Notably, bacteria typically residing on the mucosa of healthy individuals were mostly obligate anaerobes, whereas in the inflamed mucosa an increase of facultative anaerobe and aerobic bacteria was observed. We also identify potential co-occurring and mutually exclusive interactions between bacteria associated with the healthy and inflamed mucosa, which appear to be determined by the oxygen availability and the type of respiration. Finally, we identified a panel of bacterial biomarkers that allow the discrimination between eubiosis from dysbiosis with a high diagnostic performance (96% accurately), which could be used for the development of non-invasive diagnostic methods. Thus, this study is a step forward towards understanding the landscapes and alterations of mucosa-associated intestinal microbiota in patients with IBDs.

Intestinal flora differences between patients with ulcerative colitis of different ethnic groups in China

To determine the differences in intestinal flora between Uygur and Han patients with ulcerative colitis (UC).Microbial diversity and structural composition of fecal bacteria from patients with UC and their matched healthy spouses or first-degree relatives were analyzed using high-throughput sequencing technology.The fecal microbial diversity and abundance index of Uygur patients with UC (UUC) were significantly lower compared with the Uygur normal control group, while there was no significant difference between the Han UC patients (HUC) and the Han normal control group (HN). Compared with their respective control groups, Uygur UC patients and Han UC patients had a different main composition of human intestinal flora (P < .05). The abundance of Burkholderia, Caballeronia, Paraburkholderia in the UUC group were higher compared with the HUC group, while Faecalibacterium, Bifidobacterium, and Blautia in the HUC group were higher than those in the UUC group (P < .05). Veillonella in the UUC group was higher than that in the Uygur normal control group group, while Subdoligranulum and Ruminococcaceae_UCG-002 were significantly lower (P < .05). Prevotella_9 in the HUC group was significantly higher than that in HN group, while Blautia, Anaerostipes, and [Eubacterium]_hallii_group were significantly lower. Moreover, the top 6 species in order of importance were Christensenellaceae_R_7_group, Ruminococcae_ucg_005, Ruminococcae_ucg_010, Ruminococcae_ucg_013, Haemophilus, and Ezakiella.The difference in intestinal microflora structure may be one of the reasons for the clinical heterogeneity between Uygur and Han patients with UC. Christensenellaceae_R_7_group, Ruminococcae_ucg_005, Ruminococcae_ucg_010, Ruminococcae_ucg_013, Haemophilus, and Ezakiella could be used as potential biomarkers for predicting UC.

Galacto-oligosaccharides improve barrier function and relieve colonic inflammation via modulating mucosa-associated microbiota composition in lipopolysaccharides-challenged piglets

BACKGROUND

Galacto-oligosaccharides (GOS) have been shown to modulate the intestinal microbiota of suckling piglets to exert beneficial effects on intestinal function. However, the modulation of intestinal microbiota and intestinal function by GOS in intestinal inflammation injury models has rarely been reported. In this study, we investigated the effects of GOS on the colonic mucosal microbiota composition, barrier function and inflammatory response of lipopolysaccharides (LPS)-challenged suckling piglets.

METHODS

A total of 18 newborn suckling piglets were divided into three groups, the CON group, the LPS-CON group and the LPS-GOS group. Piglets in the LPS-GOS group were orally fed with 1 g/kg body weight of GOS solution every day. On the d 14, piglets in the LPS-CON and LPS-GOS group were challenged intraperitoneally with LPS solution. All piglets were slaughtered 2 h after intraperitoneal injection and sampled.

RESULTS

We found that the colonic mucosa of LPS-challenged piglets was significantly injured and shedding, while the colonic mucosa of the LPS-GOS group piglets maintained its structure. Moreover, GOS significantly reduced the concentration of malondialdehyde (MDA) and the activity of reactive oxygen species (ROS) in the LPS-challenged suckling piglets, and significantly increased the activity of total antioxidant capacity (T-AOC). GOS significantly increased the relative abundance of norank_f__Muribaculaceae and Romboutsia, and significantly decreased the relative abundance of Alloprevotella, Campylobacter and Helicobacter in the colonic mucosa of LPS-challenged suckling piglets. In addition, GOS increased the concentrations of acetate, butyrate and total short chain fatty acids (SCFAs) in the colonic digesta of LPS-challenged suckling piglets. GOS significantly reduced the concentrations of interleukin 1β (IL-1β), interleukin 6 (IL-6), tumor necrosis factor-α (TNF-α) and cluster of differentiation 14 (CD14), and the relative mRNA expression of Toll-like receptor 4 (TLR4) and myeloid differentiation primary response 88 (MyD88) in the LPS-challenged suckling piglets. In addition, GOS significantly reduced the relative mRNA expression of mucin2 (MUC2), and significantly increased the protein expression of Claudin-1 and zonula occluden-1 (ZO-1) in LPS-challenged suckling piglets.

CONCLUSIONS

These results suggested that GOS can modulate the colonic mucosa-associated microbiota composition and improve the intestinal function of LPS-challenged suckling piglets.

Comparative analysis of fecal microbiota composition diversity in Tibetan piglets suffering from diarrheagenic Escherichia coli (DEC)

This study was ascertained to investigate the adverse effects of pathogenic E. coli on gut microbiota of Tibetan piglets with history of yellow and white dysentery. For this purpose, a total of 18 fecal samples were collected from infected and healthy Tibetan piglets for 16S rRNA gene amplification and sequencing of V3-V4 region. Results showed that Firmicutes, Bacteroidia Fusobacteriota, Proteobacteria and Actinobacteriota were the predominant bacteria in Tibetan piglets at the level of phylum classification. Results on classification at family level showed that Lactobacillus, Bacteroidota, Fusobacteriota and Enterobacteriaceae were the dominant bacteria. Results on classification of bacteria at phylum level compared with normal piglets indicated that Bacteroidota, Actinobacteriota, Euryarchaota and Spirochaetota in fecal microbial community in Tibetan piglets showing yellow dysenteric and diarrhea group were significantly decreased (P ≤ 0.05). Compared with the feces of healthy Tibetan piglets, the abundance of Escherichia-Shigella, Lactobacillus and Enterococcus increased significantly in feces of Tibetan piglets having yellow dysentery and white dysentery. Moreover, results exhibited that the Proteobacteria and Fusobacteriota were significantly increased (P ≤ 0.05) suggesting dominant microbial community. Results revealed that E. coli induced different pathological alterations in intestine including damage to intestinal epithelial cells, infiltration of inflammatory cells, presence of red blood cells in spaces of tissues, hemorrhages and necrosis of intestinal villi in piglets with history of yellow dysentery. This study for the first time reported the composition, characteristics, and differences of the fecal microflora diversity of Tibetan piglets with yellow and white dysentery in Qinghai-Tibet Plateau, which can provide a suitable support for effective control of diarrhoeal disease in these animals.

Dietary simple sugars alter microbial ecology in the gut and promote colitis in mice

The higher prevalence of inflammatory bowel disease (IBD) in Western countries points to Western diet as a possible IBD risk factor. High sugar, which is linked to many noncommunicable diseases, is a hallmark of the Western diet, but its role in IBD remains unknown. Here, we studied the effects of simple sugars such as glucose and fructose on colitis pathogenesis in wild-type and Il10^-/- mice. Wild-type mice fed 10% glucose in drinking water or high-glucose diet developed severe colitis induced by dextran sulfate sodium. High-glucose-fed Il10^-/- mice also developed a worsened colitis compared to glucose-untreated Il10^-/- mice. Short-term intake of high glucose or fructose did not trigger inflammatory responses in healthy gut but markedly altered gut microbiota composition. In particular, the abundance of the mucus-degrading bacteria Akkermansia muciniphila and Bacteroides fragilis was increased. Consistently, bacteria-derived mucolytic enzymes were enriched leading to erosion of the colonic mucus layer of sugar-fed wild-type and Il10^-/- mice. Sugar-induced exacerbation of colitis was not observed when mice were treated with antibiotics or maintained in a germ-free environment, suggesting that altered microbiota played a critical role in sugar-induced colitis pathogenesis. Furthermore, germ-free mice colonized with microbiota from sugar-treated mice showed increased colitis susceptibility. Together, these data suggest that intake of simple sugars predisposes to colitis and enhances its pathogenesis via modulation of gut microbiota in mice.

Lactobacillus rhamnosus from human breast milk ameliorates ulcerative colitis in mice via gut microbiota modulation

Gut microbiota imbalance is one of the major causes of ulcerative colitis (UC). L. rhamnosus SHA113 (LRS), a strain isolated from healthy human milk, influences the regulation of gut flora. This study aims to determine whether this strain can ameliorate UC by modulating gut microbiota. Mouse models of UC were established using C57BL/6Cnc mice with intragastric administration of 3.0% (w/v) dextran sodium sulfate (DSS). LRS was used to treat the mouse models of UC with 109 cfu mL-1 cell suspension via intragastric administration. To verify the effect of gut microbiota on UC, fecal microbiota collected from the mice after the treatment with LRS were also used to treat the UC mouse models (FMT). The severity of UC was evaluated based on body weight, colon length, disease activity index (DAI), and hematoxylin-eosin staining. The microbial composition was analyzed by 16S rRNA sequencing. The mRNA expression levels of cytokines, mucins, tight junction proteins, and antimicrobial peptides in the gastrointestinal tract were detected by quantitative real-time polymerase chain reaction. The short-chain fatty acid (SCFAs) in the cecal contents of all mice were quantitatively detected by gas chromatography and mass spectrometry. Both LRS and FMT exerted excellent therapeutic effects on UC, as evidenced by the reduction in body weight loss, colon length, and colon structural integrity, as well as the increase in the DAI (disease activity index). LRS and FMT treatments showed similar effects: (1) an increase of total SCFA production in the cecal contents and the abundance of gut microbial diversity and flora composition; (2) decreases in two genera (Parabacteroides and Escherichia/Shigella) related to the DAI and the enhancement of SCFAs and IL-10 positively related genera in the gut microbiota (Bilophila, Roseburia, Akkermansia, and Bifidobacterium); (3) downregulation of the expression of tumor necrosis factor-α, interleukin IL-6, and IL-1β, and upregulation of the expression of the anti-inflammatory cytokine IL-10; and (4) upregulation of the expression of mucins (Muc1-4) and tight junction protein ZO-1. Overall, L. rhamnosus SHA113 relieves UC via the regulation of gut microbiota: increases in SCFA-producing genera and decreases in UC-related genera. In addition, a single strain is sufficient to induce a significant change in the gut microbiota and exert therapeutic effects on UC.

Role of melatonin in murine "restraint stress"-induced dysfunction of colonic microbiota

Intestinal diseases caused by physiological stress have become a severe public health threat worldwide. Disturbances in the gut microbiota-host relationship have been associated with irritable bowel disease (IBD), while melatonin (MT) has anti-inflammatory and antioxidant effects. The objective of this study was to investigate the mechanisms by which MT-mediated protection mitigated stress-induced intestinal microbiota dysbiosis and inflammation. We successfully established a murine restraint stress model with and without MT supplementation. Mice subjected to restraint stress had significantly elevated corticosterone (CORT) levels, decreased MT levels in their plasma, elevated colonic ROS levels and increased bacterial abundance, including Bacteroides and Tyzzerella, in their colon tract, which led to elevated expression of Toll-like receptor (TLR) 2/4, p-P65 and p-IKB. In contrast, supplementation with 20 mg/kg MT reversed the elevation of the plasma CORT levels, downregulated the colon ROS levels and inhibited the changes in the intestinal microbiota induced by restraint stress. These effects, in turn, inhibited the activities of TLR2 and TLR4, p-P65 and p-IκB, and decreased the inflammatory reaction induced by restraint stress. Our results suggested that MT may mitigate "restraint stress"-induced colonic microbiota dysbiosis and intestinal inflammation by inhibiting the activation of the NF-κB pathway.

Macrophage cytokine responses to commensal Gram-positive Lactobacillus salivarius strains are TLR2-independent and Myd88-dependent

The mechanisms through which cells of the host innate immune system distinguish commensal bacteria from pathogens are currently unclear. Toll-like receptors (TLRs) are a class of pattern recognition receptors (PRRs) expressed by host cells which recognize microbe-associated molecular patterns (MAMPs) common to both commensal and pathogenic bacteria. Of the different TLRs, TLR2/6 recognize bacterial lipopeptides and trigger cytokines responses, especially to Gram-positive and Gram-negative pathogens. We report here that TLR2 is dispensable for triggering macrophage cytokine responses to different strains of the Gram-positive commensal bacterial species Lactobacillus salivarius. The L. salivarius UCC118 strain strongly upregulated expression of the PRRs, Mincle (Clec4e), TLR1 and TLR2 in macrophages while downregulating other TLR pathways. Cytokine responses triggered by L. salivarius UCC118 were predominantly TLR2-independent but MyD88-dependent. However, macrophage cytokine responses triggered by another Gram-positive commensal bacteria, Bifidobacterium breve UCC2003 were predominantly TLR2-dependent. Thus, we report a differential requirement for TLR2-dependency in triggering macrophage cytokine responses to different commensal Gram-positive bacteria. Furthermore, TNF-α responses to the TLR2 ligand FSL-1 and L. salivarius UCC118 were partially Mincle-dependent suggesting that PRR pathways such as Mincle contribute to the recognition of MAMPs on distinct Gram-positive commensal bacteria. Ultimately, integration of signals from these different PRR pathways and other MyD88-dependent pathways may determine immune responses to commensal bacteria at the host-microbe interface.

Gut Microbiota Dysbiosis Associated with Persistent Fatigue in Hematopoietic Cell Transplantation Survivors

Fatigue is one of the most prevalent and distressing complications among hematopoietic stem cell transplantation (HCT) survivors, negatively affecting physical, social, and emotional domains of quality of life. Chronic systemic inflammation has been linked to alterations in nervous system activity and initiation of distressing symptoms, such as fatigue. Damage to gut mucosa due to alteration in gut microbiota (GM) composition and microbial translocation has been shown to increase systemic proinflammatory cytokines. The aim of this study was to evaluate the relationship between fatigue and GM by measuring the differences in GM composition in HCT survivors with and without persistent fatigue. This cross-sectional study included 30 adults who underwent HCT for a hematologic disease and were at least 1 year post-HCT. Patients with chronic graft-versus-host disease were excluded. Fatigue severity was assessed by the Brief Fatigue Inventory (BFI). Based on the BFI score, patients were grouped into 2 categories: 0 to 3 (without fatigue) and ≥4 (with fatigue). The V1 to V3 region of the 16S rRNA gene from fecal specimens was sequenced using the Illumina MiSeq. Sequencing reads were processed, denoised, and replicated, chimeras were filtered, amplicon sequence variants (ASVs) were generated, and taxonomy was assigned using DADA2. Beta diversity analysis through principal coordinate analysis was generated using the Bray-Curtis dissimilarity matrix, and the difference was tested using linear model with generalized least squares in R. An alpha diversity analysis was performed using Chao1. Linear discriminant analysis effect size (LEfSe) was used to find markers that differ between the 2 groups. Based on the BFI results, patients were categorized into 2 cohorts: with fatigue (n = 14) and without fatigue (n = 16). The 2 cohorts were similar in terms of demographics, disease, and transplant characteristics. Based on the GM analysis, there was a significant difference in GM composition (beta diversity) between the 2 cohorts (P = .001). Alpha diversity (richness) was also significantly lower in survivors with fatigue (P =.002). LEfSe analysis identified 46 discriminative features (P < .05; linear discriminant analysis score >2) whose relative abundance varied significantly among individuals with fatigue and those without fatigue. Ten ASVs were associated with the patients with fatigue, and 36 ASVs were associated with those without fatigue. Several ASVs enriched in survivors with fatigue included organisms such as Klebsiella and Enterococcus, which have been implicated in inflammatory bowel diseases. The ASVs enriched in the cohort without fatigue were members of the Ruminococcaceae family (Oscillospira spp) and the Lachnospiraceae family (Fusicatenibacter and Coprococcus spp), which are known to have the ability to ferment complex plant carbohydrates. These findings show an association between GM composition and fatigue and suggest a microbial contribution to clinically significant fatigue post-HCT, which may guide the development of new approaches to treating fatigue based on manipulation of the GM.

Models to evaluate the barrier properties of mucus during drug diffusion

Mucus is widely disseminated in the nasal cavity, oral cavity, respiratory tract, eyes, gastrointestinal tract, and reproductive tract to prevent the invasion of pathogenic bacteria and toxins. The mucus layer through its continuous secretion can prevent the passage of macromolecular substances such as pathogenic bacteria and toxins, thereby reducing the occurrence of inflammation. Without a doubt, mucus also hinders oral absorption. The physiological and biochemical properties of intestinal mucus and the different types of mucus barrier models need to be predominated. To find ways to increase the bioavailability of drugs in the future, this article summarizes mucus composition, barrier properties, mucus models, and mucoadhesive/mucopenetrating particles to highlight the information they can afford. Collectively, the review seeks to provide a state-of-the-art roadmap for researchers who must contend with this critical barrier to drug delivery.

Diet and Inflammatory Bowel Disease: What Quality Standards Should Be Applied in Clinical and Laboratory Studies?

Many patients suffering from inflammatory bowel disease (IBD) follow restrictive diets, as many respective recommendations circulate. Efforts are made to evaluate and summarize the published information, for example, in a recent consensus manuscript by the International Organization for the Study of IBD (IOIBD). However, the standards that should be applied to make claims about dietary effects are poorly defined. In this manuscript, the scientific basis of recommendations for nutritional interventions in IBD is analyzed. Epidemiological evidence on diet in IBD is always biased by numerous factors, and the number of robust dietary intervention studies is limited due to methodological difficulties. Therefore, animal models are used to test hypotheses with respect to dietary factors and intestinal inflammation. Naturally, animal models have limitations, and knowledge of key characteristics of colitis animal models is crucial to understand their advantages and disadvantages. In recent years the important role of the microbiota for IBD and dietary factors has been discovered. Microbiota data are added to many publications on IBD and nutrition. The quality of those data varies largely. Subsequently, quality standards for microbiota analyses also are discussed. Finally, quality requirements to be applied on recommendations for dietary changes in patients with IBD are suggested.