Celiac Disease and the Microbiome

Fucoidan modulates gut microbiota and immunity in Peyer's patches against inflammatory bowel disease

Although fucoidan has potential use as an anti-inflammatory agent, the specific mechanisms by which it influences signaling and immunomodulatory pathways between gut microbiota and Peyer's patches remain unclear. Therefore, the aim of this study was to investigate the therapeutic potential of fucoidan in a dextran sulfate sodium (DSS)-induced mouse model of inflammatory bowel disease (IBD) by examining the effects on gut microbiota and the underlying anti-inflammatory mechanisms. Purified fucoidan, which upon characterization revealed structural fragments comprising →3)-β-D-Galp-(1→, →4)-α-L-Fucp-(1→, and →3)-α-L-Fucp-(1→ residues with a sulfation at position C2 was used. Treatment of the mice with fucoidan significantly alleviated the symptoms of IBD and restored the diversity of gut microbiota by enhancing the abundance of Bacteroidetes and reducing the proportion of Firmicutes. The administration of fucoidan also elevated levels of short-chain fatty acids while reducing the levels of pro-inflammatory cytokines, including interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α, and interferon (IFN)-γ. Most importantly, fucoidan attenuated the expression of integrin α4β7/MAdCAM-1 and CCL25/CCR9, which are involved in homing intestinal lymphocytes within Peyer's patches. These findings indicate that fucoidan is a promising gut microbiota modulator and an anti-inflammatory agent for IBD.

A Deep Learning-Based Approach to Estimate Paneth Cell Granule Area in Celiac Disease

CONTEXT.—

Changes in Paneth cell numbers can be associated with chronic inflammatory diseases of the gastrointestinal tract. So far, no consensus has been achieved on the number of Paneth cells and their relevance to celiac disease (CD).

OBJECTIVES.—

To compare crypt and Paneth cell granule areas between patients with CD and those without CD (non-CD) using an artificial intelligence-based solution.

DESIGN.—

Hematoxylin-eosin-stained sections of duodenal biopsies from 349 patients at the McGill University Health Centre were analyzed. Of these, 185 had a history of CD and 164 were controls. Slides were digitized, and NoCodeSeg, a code-free workflow using open-source software (QuPath, DeepMIB), was implemented to train deep learning models to segment crypts and Paneth cell granules. The total area of the entire analyzed tissue, epithelium, crypts, and Paneth cell granules was documented for all slides, and comparisons were performed.

RESULTS.—

A mean intersection-over-union score of 88.76% and 91.30% was achieved for crypt areas and Paneth cell granule segmentations, respectively. On normalization to total tissue area, the crypt to total tissue area in CD was increased and the Paneth cell granule area to total tissue area decreased when compared to non-CD controls.

CONCLUSIONS.—

Crypt hyperplasia was confirmed in CD compared to non-CD controls. The area of Paneth cell granules, an indirect measure of Paneth cell function, decreased with increasing severity of CD. More importantly, our study analyzed complete hematoxylin-eosin slide sections using an efficient and easy to use coding-free artificial intelligence workflow.

How the Microbiota May Affect Celiac Disease and What We Can Do

Celiac disease (CeD) is an autoimmune disease with a strong association with human leukocyte antigen (HLA), characterized by the production of specific autoantibodies and immune-mediated enterocyte killing. CeD is a unique autoimmune condition, as it is the only one in which the environmental trigger is known: gluten, a storage protein present in wheat, barley, and rye. How and when the loss of tolerance of the intestinal mucosa to gluten occurs is still unknown. This event, through the activation of adaptive immune responses, enhances epithelial cell death, increases the permeability of the epithelial barrier, and induces secretion of pro-inflammatory cytokines, resulting in the transition from genetic predisposition to the actual onset of the disease. While the role of gastrointestinal infections as a possible trigger has been considered on the basis of a possible mechanism of antigen mimicry, a more likely alternative mechanism appears to involve a complex disruption of the gastrointestinal microbiota ecosystem triggered by infections, rather than the specific effect of a single pathogen on intestinal mucosal homeostasis. Several lines of evidence show the existence of intestinal dysbiosis that precedes the onset of CeD in genetically at-risk subjects, characterized by the loss of protective bacterial elements that both epigenetically and functionally can influence the response of the intestinal epithelium leading to the loss of gluten tolerance. We have conducted a literature review in order to summarize the current knowledge about the complex and in part still unraveled dysbiosis that precedes and accompanies CeD and present some exciting new data on how this dysbiosis might be prevented and/or counteracted. The literature search was conducted on PubMed.gov in the time frame 2010 to March 2024 utilizing the terms "celiac disease and microbiota", "celiac disease and microbiome", and "celiac disease and probiotics" and restricting the search to the following article types: Clinical Trials, Meta-Analysis, Review, and Systematic Review. A total of 364 papers were identified and reviewed. The main conclusions of this review can be outlined as follows: (1) quantitative and qualitative changes in gut microbiota have been clearly documented in CeD patients; (2) intestinal microbiota's extensive and variable interactions with enterocytes, viral and bacterial pathogens and even gluten combine to impact the inflammatory immune response to gluten and the loss of gluten tolerance, ultimately affecting the pathogenesis, progression, and clinical expression of CeD; (3) gluten-free diet fails to restore the eubiosis of the digestive tract in CeD patients, and also negatively affects microbial homeostasis; (4) new tools allowing targeted microbiota therapy, such as the use of probiotics (a good example being precision probiotics like the novel strain of B. vulgatus (20220303-A2) begin to show exciting potential applications.

Vitamin D: An Essential Nutrient in the Dual Relationship between Autoimmune Thyroid Diseases and Celiac Disease-A Comprehensive Review

Autoimmune thyroid diseases (AITD) are among the most frequent autoimmune disorders, with a multifactorial etiology in which both genetic and environmental determinants are probably involved. Celiac disease (CeD) also represents a public concern, given its increasing prevalence due to the recent improvement of screening programs, leading to the detection of silent subtypes. The two conditions may be closely associated due to common risk factors, including genetic setting, changes in the composition and diversity of the gut microbiota, and deficiency of nutrients like vitamin D. This comprehensive review discussed the current evidence on the pivotal role of vitamin D in modulating both gut microbiota dysbiosis and immune system dysfunction, shedding light on the possible relevance of an adequate intake of this nutrient in the primary prevention of AITD and CeD. While future technology-based strategies for proper vitamin D supplementation could be attractive in the context of personalized medicine, several issues remain to be defined, including standardized assays for vitamin D determination, timely recommendations on vitamin D intake for immune system functioning, and longitudinal studies and randomized controlled trials to definitely establish a causal relationship between serum vitamin D levels and the onset of AITD and CeD.

Microbiome in cancer: A comparative analysis between humans and dogs

Cancer is a major cause of death in humans and animals worldwide. While cancer survival rates have increased over recent decades, further research to identify risk factors for the onset and progression of disease, and safe and highly efficacious treatments, is needed. Spontaneous tumours in pets represent an excellent model for neoplastic disease in humans. In this regard, dogs are an interesting species, as the divergence between the dog and human genome is low, humans and dogs have important similarities in the development and functioning of the immune system, and both species often share the same physical environment. There is also a higher homology between the canine and human microbiome than murine model. This review aims to describe and organize recently published information on canine microbiome assemblages and their relationship with the onset and progression of colorectal cancer, breast cancer and lymphoma, and to compare this with human disease. In both species, dysbiosis can induce variations in the gut microbiota that strongly influence shifts in status between health and disease. This can produce an inflammatory state, potentially leading to neoplasia, especially in the intestine, thus supporting canine studies in comparative oncology. Intestinal dysbiosis can also alter the efficacy and side effects of cancer treatments. Fewer published studies are available on changes in the relevant microbiomes in canine lymphoma and mammary cancer, and further research in this area could improve our understanding of the role of microbiota in the development of these cancers.

Monitoring coeliac disease in 2024, time to change practice?

PURPOSE OF REVIEW

Persistent villous atrophy is associated with morbidity in coeliac disease and most commonly due to ongoing gluten ingestion. Current methods for assessing gluten exposure and persisting villous atrophy include dietary questionnaires and repeat duodenal biopsy, which have limited accuracy or are invasive. This review discusses adjunctive and/or novel tests that could be used to overcome these challenges.

RECENT FINDINGS

Small bowel capsule endoscopy is well tolerated and helps to evaluate for persisting villous atrophy and importantly, complications associated with coeliac disease. Testing for urinary and/or stool gluten immunogenic peptides may help identify recent gluten exposure, but further studies are still warranted to evaluate the accuracy and applicability of this approach. Measuring spikes in circulating Interleukin-2 following gluten challenge has shown promise for coeliac disease diagnosis, and thus may serve as a useful confirmatory test in those with persisting symptoms but provides no information on mucosal inflammation. No specific gut microbial signature has been identified in coeliac disease; however, studies have shown a reduced microbial diversity in active disease, which with future refinement may prove clinically useful.

SUMMARY

There is no evidence to support alternative methods for assessing persisting villous atrophy in coeliac disease over performing an up-to-date duodenal biopsy. Monitoring for adherence to a gluten-free diet remains clinically challenging and should be a priority for future research.

From an understanding of etiopathogenesis to novel therapies-what is new in the treatment of celiac disease?

Celiac disease, a chronic autoimmune disorder caused by genetic factors and exposure to gluten, is increasingly being recognized and diagnosed in both children and adults. Scientists have been searching for a cure for this disease for many years, but despite the impressive development of knowledge in this field, a gluten-free diet remains the only recommended therapy for all patients. At the same time, the increasing diagnosis of celiac disease in adults, which was considered a childhood disease in the 20th century, has opened a discussion on the etiopathology of the disease, which is proven to be very complex and involves genetic, immunological, nutritional, environmental and gut microbiota-related factors. In this review, we extensively discuss these factors and summarize the knowledge of the proposed state-of-the-art treatments for celiac disease to address the question of whether a better understanding of the etiopathogenesis of celiac disease has opened new directions for therapy.

Celiac disease and depressive disorders as nutritional implications related to common factors - A comprehensive review

Celiac disease (CD) is an immune-mediated disease affecting the small intestine. The only treatment strategy for CD is the gluten-free diet (GFD). One of the more common mental disorders in CD patients is major depressive disorder (MDD). The influence of GFD on the occurrence of MDD symptoms in patients with CD will be evaluated. This diet often reduces nutritional deficiencies in these patients and also helps to reduce depressive symptoms. Both disease entities are often dominated by the same deficiencies of nutrients such as iron, zinc, selenium, iodine, or B and D vitamins. Deficiencies of particular components in CD can favor MDD and vice versa. Gluten can adversely affect the mental state of patients without CD. Also, intestinal microbiota may play an important role in the described process. This work aims to comprehensively assess the common factors involved in the pathomechanisms of MDD and CD, with particular emphasis on nutrient imbalances. Given the complexity of both disease entities, and the many common links, more research related to improving mental health in these patients and the implementation of a GFD would need to be conducted, but it appears to be a viable pathway to improving the quality of life and health of people struggling with CD and MDD. Therefore, probiotics, micronutrients, macronutrients, and vitamin supplements are recommended to reduce the risk of MDD, given that they may alleviate the symptoms of both these disease entities. In turn, in patients with MDD, it is worth considering testing for CD.

Bacteria: Potential Make-or-Break Determinants of Celiac Disease

Celiac disease is an autoimmune disease triggered by dietary gluten in genetically susceptible individuals that primarily affects the small intestinal mucosa. The sole treatment is a gluten-free diet that places a social and economic burden on patients and fails, in some, to lead to symptomatic or mucosal healing. Thus, an alternative treatment has long been sought after. Clinical studies on celiac disease have shown an association between the presence of certain microbes and disease outcomes. However, the mechanisms that underlie the effects of microbes in celiac disease remain unclear. Recent studies have employed disease models that have provided insights into disease mechanisms possibly mediated by bacteria in celiac disease. Here, we have reviewed the bacteria and related mechanisms identified so far that might protect from or incite the development of celiac disease. Evidence indicates bacteria play a role in celiac disease and it is worth continuing to explore this, particularly since few studies, to the best of our knowledge, have focused on establishing a mechanistic link between bacteria and celiac disease. Uncovering host-microbe interactions and their influence on host responses to gluten may enable the discovery of pathogenic targets and development of new therapeutic or preventive approaches.

Temporal variations in the gut microbial diversity in response to high-fat diet and exercise

High-fat diet-induced obesity is a pandemic caused by an inactive lifestyle and increased consumption of Western diets and is a major risk factor for diabetes and cardiovascular diseases. In contrast, exercise can positively influence gut microbial diversity and is linked to a decreased inflammatory state. To understand the gut microbial variations associated with exercise and high-fat diet over time, we conducted a longitudinal study to examine the effect of covariates on gut microbial diversity and composition. Young mice were divided into four groups: Chow-diet (CHD), high-fat diet (HFD), high-fat diet + exercise (HFX), and exercise only (EXE) and underwent experimental intervention for 12 weeks. Fecal samples at week 0 and 12 were collected for DNA extraction, followed by 16S library preparation and sequencing. Data were analyzed using QIIME 2, R and MicrobiomeAnalyst. The Bacteroidetes-to-Firmicutes ratio decreased fivefold in the HFD and HFX groups compared to that in the CHD and EXE groups and increased in the EXE group over time. Alpha diversity was significantly increased in the EXE group longitudinally (p < 0.02), whereas diversity (Shannon, Faith's PD, and Fisher) and richness (ACE) was significantly reduced in the HFD (p < 0.005) and HFX (p < 0.03) groups over time. Beta diversity, based on the Jaccard, Bray-Curtis, and unweighted UniFrac distance metrics, was significant among the groups. Prevotella, Paraprevotella, Candidatus arthromitus, Lactobacillus salivarius, L. reuteri, Roseburia, Bacteroides uniformis, Sutterella, and Corynebacterium were differentially abundant in the chow-diet groups (CHD and EXE). Exercise significantly reduced the proportion of taxa characteristic of a high-fat diet, including Butyricimonas, Ruminococcus gnavus, and Mucispirillum schaedleri. Diet, age, and exercise significantly contributed to explaining the bacterial community structure and diversity in the gut microbiota. Modulating the gut microbiota and maintaining its stability can lead to targeted microbiome therapies to manage chronic and recurrent diseases and infections.

Total serum IgA levels and HLA-DQB1*02:01 allelic status

Immunoglobulin A Deficiency (IgAD) is the most common primary immunodeficiency and is significantly associated with Celiac Disease (CD), which recognizes a specific background of human leukocyte antigens (HLA) predisposition (including HLA-DQB1*02:01 allele). A number of studies investigated the role of HLA in IgAD etiopathogenesis: HLA-DQB1*02 alleles are included in the main haplotypes linked to this primary immunodeficiency. In this preliminary study, we investigated the potential impact of HLA-DQB1*02:01 allelic status on total serum IgA levels: 108 serum samples from the bone marrow donors' registry were analyzed for total IgA concentration with respect to the HLA-DQB1*02:01 status. Although total serum IgA levels between HLA-DQB1*02:01 carriers and HLA-DQB1*02:01 negative donors were not different, we observed a statistically significant difference (p=0.0118) in total serum IgA levels among donors with low IgA concentration (<80mg/dL) in the sub-analysis between HLA-DQB1*02:01 positive group (including both homozygous and heterozygous carriers) compared to HLA-DQB1*02:01 negative donors. Our results might suggest a role of HLA-DQB1*02:01 allelic variant in the determination of total serum IgA levels, at least in patients affected with IgA deficiency and/or otherwise predisposed to it; however, larger and more standardized studies are needed to confirm this speculation.

The Contribution of the Intestinal Microbiota to the Celiac Disease Pathogenesis along with the Effectiveness of Probiotic Therapy

The development of many human disorders, including celiac disease (CD), is thought to be influenced by the microbiota of the gastrointestinal tract and its metabolites, according to current research. This study's goal was to provide a concise summary of the information on the contribution of the intestinal microbiota to the CD pathogenesis, which was actively addressed while examining the reported pathogenesis of celiac disease (CD). We assumed that a change in gluten tolerance is formed under the influence of a number of different factors, including genetic predisposition and environmental factors. In related investigations, researchers have paid increasing attention to the study of disturbances in the composition of the intestinal microbiota and its functional activity in CD. A key finding of our review is that the intestinal microbiota has gluten-degrading properties, which, in turn, may have a protective effect on the development of CD. The intestinal microbiota contributes to maintaining the integrity of the intestinal barrier, preventing the formation of a "leaky" intestine. On the contrary, a change in the composition of the microbiota can act as a significant link in the pathogenesis of gluten intolerance and exacerbate the course of the disease. The possibility of modulating the composition of the microbiota by prescribing probiotic preparations is being considered. The effectiveness of the use of probiotics containing Lactobacillus and Bifidobacterium bacteria in experimental and clinical studies as a preventive and therapeutic agent has been documented.

The Gut Microbiome from a Biomarker to a Novel Therapeutic Strategy for Immunotherapy Response in Patients with Lung Cancer

The gastrointestinal microbiome has been shown to play a key role in determining the responses to cancer immunotherapy, including immune checkpoint inhibitor (ICI) therapy and CAR-T. In patients with non-small cell lung cancer (NSCLC), increasing evidence suggests that a microbiome composition signature is associated with clinical response to ICIs as well as with the development of immune-related adverse events. In support of this, antibiotic (ATB)-related dysbiosis has been consistently linked with the deleterious impact of ICI response, shortening the overall survival (OS) among patients on ATBs prior to ICI initiation. In parallel, several preclinical experiments have unravelled various strategies using probiotics, prebiotics, diet, and fecal microbiota transplantation as new therapeutic tools to beneficially shift the microbiome and enhance ICI efficacy. These approaches are currently being evaluated in clinical trials and have achieved encouraging preliminary results. In this article, we reviewed the recent studies on the gut microbiome as a potential biomarker and an adjuvant therapy to ICIs in NSCLC patients.

The Role of Intestinal Microbiota in Celiac Disease and Further Therapeutic Perspectives

Celiac disease (CD) is an immune-mediated enteropathy caused by exposure to gluten and related prolamins in genetically susceptible individuals. It is a complex genetic disorder with multiple contributing genes. Linkage studies have identified several genomic regions that probably contain CD susceptibility genes. The most important genetic factors are HLA-DQ2 and DQ8. Several known environmental triggers promote the onset of CD at any age after gluten introduction in individuals with a genetic background, such as viral infections and intestinal dysbiosis. Recent publications have described the interference of the intestinal microbiome in gluten metabolism, modulation of local immune reactions, and in maintaining normal gut permeability. These results have promoted further lines of research on the benefit of probiotic administration to prevent disease onset or alleviate clinical symptoms along with a gluten-free diet (GFD). The relationship between gut microbiome changes and the onset of CD is incompletely understood, still being the subject of current research. This narrative review analyzes the interplay between environmental factors, intestinal microbiome alterations, and the course of CD. Furthermore, this review sets out to discuss if modulation of intestinal microflora with pre- and probiotics along with a GFD could represent a reliable therapeutic target for celiac patients.

Role of mucosal immunity and epithelial-vascular barrier in modulating gut homeostasis

The intestinal mucosa represents the most extensive human barrier having a defense function against microbial and food antigens. This barrier is represented externally by a mucus layer, consisting mainly of mucins, antimicrobial peptides, and secretory immunoglobulin A (sIgA), which serves as the first interaction with the intestinal microbiota. Below is placed the epithelial monolayer, comprising enterocytes and specialized cells, such as goblet cells, Paneth cells, enterochromaffin cells, and others, each with a specific protective, endocrine, or immune function. This layer interacts with both the luminal environment and the underlying lamina propria, where mucosal immunity processes primarily take place. Specifically, the interaction between the microbiota and an intact mucosal barrier results in the activation of tolerogenic processes, mainly mediated by FOXP3+ regulatory T cells, underlying intestinal homeostasis. Conversely, the impairment of the mucosal barrier function, the alteration of the normal luminal microbiota composition (dysbiosis), or the imbalance between pro- and anti-inflammatory mucosal factors may result in inflammation and disease. Another crucial component of the intestinal barrier is the gut-vascular barrier, formed by endothelial cells, pericytes, and glial cells, which regulates the passage of molecules into the bloodstream. The aim of this review is to examine the various components of the intestinal barrier, assessing their interaction with the mucosal immune system, and focus on the immunological processes underlying homeostasis or inflammation.

Effects of Lactiplantibacillus plantarum and Lacticaseibacillus paracasei supplementation on the faecal metabolome in children with coeliac disease autoimmunity: a randomised, double-blinded placebo-controlled clinical trial

Introduction

Coeliac disease is a lifelong immune-mediated enteropathy manifested as gluten intolerance in individuals carrying specific human leukocyte antigen (HLA) molecules. Other factors than genetics and gluten intake, however, may play a role in triggering the disease. The gut internal environment is thought to be one of these potential contributing factors, and it can be influenced throughout life.

Methods

We examine the impact of Lactiplantibacillus plantarum HEAL9 and Lacticaseibacillus paracasei 8700:2 supplementation on the faecal metabolome in genetically predisposed children having tissue transglutaminase autoantibodies, i.e., coeliac disease autoimmunity. Probiotic strains were selected based on their beneficial properties, including mucosal permeability and immune modulation effects. The intervention group (n = 40) and control group (n = 38) took the probiotics or placebo daily for 6 months in a double-blinded randomised trial. Faecal samples were collected at baseline and after 3 and 6 months and analysed using the 1H NMR for metabolome. The incorporation of 16S rRNA sequencing as a supportive dataset complemented the analysis of the metabolome data.

Results

During the 6 months of intervention, the stool concentrations of 4-hydroxyphenylacetate increased in the intervention group as compared to controls, whereas concentrations of threonine, valine, leucine, isoleucine, methionine, phenylalanine, aspartate, and fumarate decreased. Additionally, a noteworthy effect on the glycine, serine, and threonine metabolic pathway has been observed.

Conclusion

The findings suggest a modest yet significant impact of the probiotics on the faecal metabolome, primarily influencing proteolytic processes in the gut.

Clinical trial registration

ClinicalTrials.gov, NCT03176095.

Two-Sample Mendelian Randomization detects bidirectional causality between gut microbiota and celiac disease in individuals with high genetic risk

Background

Celiac Disease (CeD) is an autoimmune disorder triggered by gluten intake in genetically susceptible individuals. Highest risk individuals are homozygous for the Human Leucocyte Antigen (HLA) DQ2.5 haplotype or DQ2.5/DQ2.2 heterozygous. Both the HLA-DQ2-positive high genetic risk individuals and those that have developed the disease have altered intestinal microbiota, but it remains unclear whether these alterations are a cause or a consequence of CeD.

Objective

To investigate a potential bidirectional causality between gut microbiota (GM) and CeD in HLA-DQ2 high genetic risk individuals.

Materials and Methods

We performed a bidirectional Two-Sample Mendelian Randomization (2SMR) test using summary statistics from the largest publicly available Genome-Wide Association Study (GWAS) of GM and the summary statistics of the Immunochip CeD study of those individuals with the HLA-DQ2 high-risk haplotype. To test whether changes in GM composition were causally linked to CeD, GM data were used as exposure and CeD data as outcome; to test for reverse causation, the exposure and outcome datasets were inverted.

Results

We identified several bacteria from Ruminococcaceae and Lachnospiraceae families of the Firmicutes phylum as potentially causal in both directions. In addition, our results suggest that changes in the abundance of Veillonellaceae family might be causal in the development of CeD, while alterations in Pasteurellaceae family might be a consequence of the disease itself.

Conclusion

Our results suggest that the relationship between GM and HLA-DQ2 high risk individuals is highly complex and bidirectional.

Assessment of causal associations among gut microbiota, metabolites, and celiac disease: a bidirectional Mendelian randomization study

Background

A growing number of studies have implicated that gut microbial abundance and metabolite concentration alterations are associated with celiac disease (CD). However, the causal relationship underlying these associations is unclear. Here, we used Mendelian randomization (MR) to reveal the causal effect of gut microbiota and metabolites on CD.

Methods

Genome-wide association study (GWAS) summary-level data for gut microbiota, metabolites, and CD were extracted from published GWASs. Causal bacterial taxa and metabolites for CD were determined by two-sample MR analyses. The robustness of the results was assessed with sensitivity analyses. Finally, reverse causality was investigated with a reverse MR analysis.

Results

Genetically, increased genus Bifidobacterium was potentially associated with higher CD risk (odds ratio [OR] = 1.447, 95% confidence interval [CI]: 1.054-1.988, p = 0.022) while phylum Lentisphaerae (OR = 0.798, 95% CI: 0.648-0.983, p = 0.034) and genus Coprobacter (OR = 0.683, 95% CI: 0.531-0.880, p = 0.003) were related to lower CD risk. Moreover, there were suggestive associations between CD and the following seven metabolites: 1-oleoylglycerophosphoethanolamine, 1-palmitoylglycerophosphoethanolamine, 1,6-anhydroglucose, phenylacetylglutamine, tryptophan betaine, 10-undecenoate, and tyrosine. Sensitivity analyses deemed the results reliable without pleiotropy.

Conclusion

We investigated the causal relationships between gut microbiota, metabolites, and CD with two-sample MR. Our findings suggest several novel potential therapeutic targets for CD treatment. Further understanding of the underlying mechanism may provide insights into CD pathogenesis.

Sjögren's Syndrome Treatments in the Microbiome Era

Sjögren's syndrome (SS) is a chronic autoimmune disease characterized by inflammatory cell infiltration of the salivary and lacrimal glands, resulting in acinar epithelial cell atrophy, cell death, and loss of exocrine function. At least half of SS patients develop extraglandular inflammatory disease and have a wide range of systemic clinical manifestations that can affect any organ system, including connective tissues. As many as 3.1 million people in the U.S. suffer from SS, a disease that causes severe impairment. Women are nine times more likely than men to be affected by this condition. Unfortunately, there is currently no effective treatment for SS, and the available options only provide partial relief. Treatment involves using replacement therapies such as artificial saliva and eye lubricants, or immunosuppressive agents that have limited efficacy. The medical community recognizes that there is a significant need for more effective treatments for SS. Increasing evidence demonstrates the links between the dysfunction of the human microbial community and the onset and development of many human diseases, signifying the potential use of microorganisms as an alternative strategy to conquer these issues. The role of the microbiome in controlling immune function of the human host in the context of autoimmune diseases like SS is now becoming better understood and may help to enable new drug development strategies. Natural probiotics and synthetic biology applications hold promise for novel treatment approaches to solve the encryption of many complex and multifactorial immune disorders, like SS.

The Role of Gluten in Gastrointestinal Disorders: A Review

Gluten is only partially digested by intestinal enzymes and can generate peptides that can alter intestinal permeability, facilitating bacterial translocation, thus affecting the immune system. Few studies addressed the role of diet with gluten in the development of intestinal inflammation and in other gastrointestinal disorders. The aim of this narrative review was to analyse the role of gluten in several gastrointestinal diseases so as to give a useful overview of its effectiveness in the prevention and management of these disorders.

Oral microbiome variations related to ageing: possible implications beyond oral health

The global population is getting older due to a combination of longer life expectancy and declining birth rates. Growing evidence suggests that the oral microbiota composition and distribution may have a profound effect on how well we age. The purpose of this study was to investigate age-related oral microbiome variations of supragingival plaque and buccal mucosa samples in the general population in Latvia. Our results indicated significant difference between supragingival plaque bacterial profiles of three age groups (20-40; 40-60; 60 + years). Within supragingival plaque samples, age group 20-40 showed the highest bacterial diversity with a decline during the 40-60 age period and uprise again after the age of 60. Among other differences, the important oral commensal Neisseria had declined after the age of 40. Additionally, prevalence of two well-documented opportunistic pathogens Streptococcus anginosus and Gemella sanguinis gradually rose with age within our samples. Furthermore, supragingival plaque and buccal mucosa samples significantly differed in overall bacterial composition.

Beyond allergic progression: From molecules to microbes as barrier modulators in the gut-lung axis functionality

The "epithelial barrier hypothesis" states that a barrier dysfunction can result in allergy development due to tolerance breakdown. This barrier alteration may come from the direct contact of epithelial and immune cells with the allergens, and indirectly, through deleterious effects caused by environmental changes triggered by industrialization, pollution, and changes in the lifestyle. Apart from their protective role, epithelial cells can respond to external factors secreting IL-25 IL-33, and TSLP, provoking the activation of ILC2 cells and a Th2-biased response. Several environmental agents that influence epithelial barrier function, such as allergenic proteases, food additives or certain xenobiotics are reviewed in this paper. In addition, dietary factors that influence the allergenic response in a positive or negative way will be also described here. Finally, we discuss how the gut microbiota, its composition, and microbe-derived metabolites, such as short-chain fatty acids, alter not only the gut but also the integrity of distant epithelial barriers, focusing this review on the gut-lung axis.

Why are western diet and western lifestyle pro-inflammatory risk factors of celiac disease?

The prevalence of celiac disease increased in recent years. In addition to the genetic and immunological factors, it appears that environmental determinants are also involved in the pathophysiology of celiac disease. Gastrointestinal infections impact the development of celiac disease. Current research does not directly confirm the protective effect of natural childbirth and breastfeeding on celiac disease. However, it seems that in genetically predisposed children, the amount of gluten introduced into the diet may have an impact on celiac disease development. Also western lifestyle, including western dietary patterns high in fat, sugar, and gliadin, potentially may increase the risk of celiac disease due to changes in intestinal microbiota, intestinal permeability, or mucosal inflammation. Further research is needed to expand the knowledge of the relationship between environmental factors and the development of celiac disease to define evidence-based preventive interventions against the development of celiac disease. The manuscript summarizes current knowledge on factors predisposing to the development of celiac disease including factors associated with the western lifestyle.

Celiac Disease Genetics, Pathogenesis, and Standard Therapy for Japanese Patients

Celiac disease is an autoimmune disease primarily affecting the small intestine that is caused by the ingestion of gluten in genetically susceptible individuals. The development of celiac disease is based on a complex immune response to gluten proteins. The global average prevalence in the general population is about 1%. In recent years, it has become clear that celiac disease is not less common in Asian countries than in Western countries but often remains undiagnosed. Although the number of patients with celiac disease in Asia is expected to increase with improving disease recognition and advances in diagnostic techniques, there remain few reports of celiac disease in the Far East region of Asia, especially in Japan. In this paper, we outline the epidemiology, diagnosis, and treatment of celiac disease. In addition, we summarize the reported Japanese cases of celiac disease with an overview in Japan.

Characteristics of gut microbiota and fecal metabolomes in patients with celiac disease in Northwest China

Celiac disease (CD) is an autoimmune small bowel disease. The pattern of gut microbiota is closely related to dietary habits, genetic background, and geographical factors. There is a lack of research on CD-related gut microbiota in China. This study aimed to use 16S rDNA sequencing and metabolomics to analyze the fecal microbial composition and metabolome characteristics in patients diagnosed with CD in Northwest China, and to screen potential biomarkers that could be used for its diagnosis. A significant difference in the gut microbiota composition was observed between the CD and healthy controls groups. At the genus level, the abundance of Streptococcus, Lactobacillus, Veillonella, and Allisonella communities in the CD group were increased (Q < 0.05). Furthermore, the abundance of Ruminococcus, Faecalibacterium, Blautia, Gemmiger, and Anaerostipes community in this group were decreased (Q < 0.05). A total of 222 different fecal metabolites were identified in the two groups, suggesting that CD patients have a one-carbon metabolism defect. Four species of bacteria and six metabolites were selected as potential biomarkers using a random forest model. Correlation analysis showed that changes in the gut microbiota were significantly correlated with changes in fecal metabolite levels. In conclusion, the patterns of distribution of gut microbiota and metabolomics in patients with CD in Northwest China were found to be unique to these individuals. This has opened up a new way to explore potential beneficial effects of supplementing specific nutrients and potential diagnostic and therapeutic targets in the future.

Biogeographic Variation and Functional Pathways of the Gut Microbiota in Celiac Disease

BACKGROUND & AIMS

Genes and gluten are necessary but insufficient to cause celiac disease (CeD). Altered gut microbiota has been implicated as an additional risk factor. Variability in sampling site may confound interpretation and mechanistic insight, as CeD primarily affects the small intestine. Thus, we characterized CeD microbiota along the duodenum and in feces and verified functional impact in gnotobiotic mice.

METHODS

We used 16S rRNA gene sequencing (Illumina) and predicted gene function (PICRUSt2) in duodenal biopsies (D1, D2 and D3), aspirates, and stool from patients with active CeD and controls. CeD alleles were determined in consented participants. A subset of duodenal samples stratified according to similar CeD risk genotypes (controls DQ2^-/- or DQ2^+/- and CeD DQ2^+/-) were used for further analysis and to colonize germ-free mice for gluten metabolism studies.

RESULTS

Microbiota composition and predicted function in CeD was largely determined by intestinal location. In the duodenum, but not stool, there was higher abundance of Escherichia coli (D1), Prevotella salivae (D2), and Neisseria (D3) in CeD vs controls. Predicted bacterial protease and peptidase genes were altered in CeD and impaired gluten degradation was detected only in mice colonized with CeD microbiota.

CONCLUSIONS

Our results showed luminal and mucosal microbial niches along the gut in CeD. We identified novel microbial proteolytic pathways involved in gluten detoxification that are impaired in CeD but not in controls carrying DQ2, suggesting an association with active duodenal inflammation. Sampling site should be considered a confounding factor in microbiome studies in CeD.

Use of dexmedetomidine to alleviate intestinal ischemia-reperfusion injury via intestinal microbiota modulation in mice

Background

Intestinal ischemia-reperfusion (I/R) injury is a serious condition with unacceptable mortality rates. Our previous study revealed a protective effect of dexmedetomidine (DEX) on intestinal I/R injury, but its underlying mechanism remains unclear. Gut microbiota imbalance is associated with the progression of I/R injury. We hypothesized that DEX would attenuate intestinal I/R injury via modulating gut microbiota.

Methods

An I/R injury model was established in C57BL/6 mice in the presence or absence of DEX preconditioning. Some mice were treated with antibiotics to deplete intestinal bacteria. Fecal microbiota transplantation (FMT) was performed by transplanting the feces of DEX-pretreated mice into a new batch of I/R mice. We analyzed the expression of Bacteroidetes and Firmicutes in feces, survival rate, and inflammatory cytokines.

Results

DEX reversed I/R-induced bacterial abnormalities by increasing the ratio of Firmicutes to Bacteroidetes [DEX + I/R 3.02±0.36 vs. normal saline (NS) + I/R 0.82±0.15; 95% CI: 0.80-3.60; P<0.05] and was accompanied by increased 72-hour survival (0.40±0.16 vs. 0.10±0.09; P<0.05). The protective effect of DEX did not significantly differ from that of DEX + antibiotics. Furthermore, the bacteria of the DEX-pretreated mice decreased the release of inflammatory factors.

Conclusions

This study revealed that DEX can alleviate intestinal I/R injury through a microbiota-related mechanism, providing a potential avenue for the management of intestinal I/R injury.

The Role of the Human Microbiome in the Pathogenesis of Pain

Understanding of the gut microbiome's role in human physiology developed rapidly in recent years. Moreover, any alteration of this microenvironment could lead to a pathophysiological reaction of numerous organs. It results from the bidirectional communication of the gastrointestinal tract with the central nervous system, called the gut-brain axis. The signals in the gut-brain axis are mediated by immunological, hormonal, and neural pathways. However, it is also influenced by microorganisms in the gut. The disturbances in the gut-brain axis are associated with gastrointestinal syndromes, but recently their role in the development of different types of pain was reported. The gut microbiome could be the factor in the central sensitization of chronic pain by regulating microglia, astrocytes, and immune cells. Dysbiosis could lead to incorrect immune responses, resulting in the development of inflammatory pain such as endometriosis. Furthermore, chronic visceral pain, associated with functional gastrointestinal disorders, could result from a disruption in the gut microenvironment. Any alteration in the gut-brain axis could also trigger migraine attacks by affecting cytokine expression. Understanding the gut microbiome's role in pain pathophysiology leads to the development of analgetic therapies targeting microorganisms. Probiotics, FODMAP diet, and fecal microbiota transplantation are reported to be beneficial in treating visceral pain.

Bringing pharmacomicrobiomics to the clinic through well-designed studies

Pharmacomicrobiomic studies investigate drug-microbiome interactions, such as the effect of microbial variation on drug response and disposition. Studying and understanding the interactions between the gut microbiome and drugs is becoming increasingly relevant to clinical practice due to its potential for avoiding adverse drug reactions or predicting variability in drug response. The highly variable nature of the human microbiome presents significant challenges to assessing microbes' influence. Studies aiming to explore drug-microbiome interactions should be well-designed to account for variation in the microbiome over time and collect data on confounders such as diet, disease, concomitant drugs, and other environmental factors. Here, we assemble a set of important considerations and recommendations for the methodological features required for performing a pharmacomicrobiomic study in humans with a focus on the gut microbiome. Consideration of these factors enable discovery, reproducibility, and more accurate characterization of the relationships between a given drug and the microbiome. Furthermore, appropriate interpretation and dissemination of results from well-designed studies will push the field closer to clinical relevance and implementation.

The early-life gut microbiome and vaccine efficacy

Vaccines are one of the greatest successes of public health, preventing millions of cases of disease and death in children each year. However, the efficacy of many vaccines can vary greatly between infants from geographically and socioeconomically distinct locations. Differences in the composition of the intestinal microbiome have emerged as one of the main factors that can account for variations in immunisation outcomes. In this Review, we assess the influence of the gut microbiota upon early life immunity, focusing on two important members of the microbiota with health-promoting and immunomodulatory properties: Bifidobacterium and Bacteroides. Additionally, we discuss their immune stimulatory microbial properties, interactions with the host, and their effect on vaccine responses and efficacy in infants. We also provide an overview of current microbiota-based approaches to enhance vaccine outcomes, and describe novel microbe-derived components that could lead to safer, more effective vaccines and vaccine adjuvants.

A comprehensive map of microbial biomarkers along the gastrointestinal tract for celiac disease patients

Dysbiosis of the microbiome has been related to Celiac disease (CeD) progress, an autoimmune disease characterized by gluten intolerance developed in genetically susceptible individuals under certain environmental factors. The microbiome contributes to CeD pathophysiology, modulating the immune response by the action of short-chain fatty acids (SCFA), affecting gut barrier integrity allowing the entrance of gluten-derived proteins, and degrading immunogenic peptides of gluten through endoprolyl peptidase enzymes. Despite the evidence suggesting the implication of gut microbiome over CeD pathogenesis, there is no consensus about the specific microbial changes observed in this pathology. Here, we compiled the largest dataset of 16S prokaryotic ribosomal RNA gene high-throughput sequencing for consensus profiling. We present for the first time an integrative analysis of metataxonomic data from patients with CeD, including samples from different body sites (saliva, pharynx, duodenum, and stool). We found the presence of coordinated changes through the gastrointestinal tract (GIT) characterized by an increase in Actinobacteria species in the upper GIT (pharynx and duodenum) and an increase in Proteobacteria in the lower GIT (duodenum and stool), as well as site-specific changes evidencing a dysbiosis in patients with CeD' microbiota. Moreover, we described the effect of adherence to a gluten-free diet (GFD) evidenced by an increase in beneficial bacteria and a decrease in some Betaproteobacteriales but not fully restoring CeD-related dysbiosis. Finally, we built a Random Forest model to classify patients based on the lower GIT composition achieving good performance.

The gut microbiota and celiac disease: Pathophysiology, current perspective and new therapeutic approaches

Celiac disease (CD) as a chronic gluten-sensitive intestinal condition, mainly affects genetically susceptible hosts. The primary determinants of CD have been identified as environmental and genetic variables. The development of CD is significantly influenced by environmental factors, including the gut microbiome. Therefore, gut microbiome re-programming-based therapies using probiotics, prebiotics, postbiotics, gluten-free diet, and fecal microbiota transplantation have shown promising results in the modification of the gut microbiome. Due to the importance and paucity of information regarding the CD pathophysiology, in this review, we have covered the association between CD development and gut microbiota, the effects of infectious agents, particularly the recent Covid-19 infection in CD patients, and the efficacy of potential therapeutic approaches in the CD have been discussed. Hence, scientific literature indicates that the diverse biological functions of the gut microbiota against immunomodulatory responses have made microbiome-based therapy an alternative therapeutic paradigm to ameliorate the symptoms of CD and quality of life. However, the exact potential of microbiota-based techniques that aims to quantitatively and qualitatively alter the gut microbiota to be used in the treatment and ameliorate the symptoms of CD will be determined with further research in the future.

Microbiota profile of new-onset celiac disease in children in Saudi Arabia

Background

Intestinal dysbiosis has been reported to be associated with celiac disease (CeD) in Western populations but little is known in other populations who have different dietary lifestyle and genetic background. The purpose of this study was to determine whether a different microbiota profile is associated with CeD in children in Saudi Arabia.

Results

Forty children with CeD, 20 healthy controls, and 19 non-CeD controls were enrolled. The median age at diagnosis was 10.3, 11.3 and 10.6 years in children with CeD, fecal, and mucosal control groups, respectively. Significant differences in microbial composition between children with CeD and controls both at fecal and mucosal level were identified. Fecal samples were more diverse and richer in bacteria as compared with mucosal samples. Proteobacteria were more abundant in duodenal mucosal samples and Firmicutes and Bacteroides were more abundant in stools. The abundance of many taxa was significantly different between children with CeD and non-CeD controls. In mucosal samples, Bifidobacterium angulatum (unadjusted p = 0.006) and Roseburia intestinalis (unadjusted p = 0.031) were examples of most significantly increased species in children with CeD and non-CeD controls, respectively. In fecal samples, there were 169 bacterial species with significantly different abundance between children with CeD and non- CeD controls.

Conclusions

To our knowledge, this is the first report on the microbial profile in a non-Western population of children with new onset CeD. The fact that mucosal and fecal samples were collected from newly diagnosed children with CeD on normal gluten-containing diet suggests strong association between the identified bacteria and CeD. The identification of many unreported bacterial species significantly associated with CeD, indicates the need for further studies from different populations to expand our understanding of the role of bacteria in the pathogenesis of CeD, hopefully leading to the discovery of new adjuvant treatment options.

Recent Advancements in Understanding the Gut Microbiome and the Inner Ear Axis

The gut microbiome and its dynamic association with organ systems beyond the gastrointestinal tract, such as the nervous and cardiovascular systems, is an emerging area of research. Although the role of the gut microbiome has been extensively characterized in the gut-brain axis, the implications of gut dysbiosis in inner ear inflammation and hearing deficits have still not been explored. With some similarities outlined between the blood-brain barrier (BBB) and the blood labyrinth barrier (BLB) of the inner ear, this review aims to explore the axis between the gut microbiome and the inner ear as it pertains to their bidirectional communication.

Antioxidant and Antibacterial Effects of Potential Probiotics Isolated from Korean Fermented Foods

A total of sixteen bacterial strains were isolated and identified from the fourteen types of Korean fermented foods that were evaluated for their in vitro probiotic potentials. The results showed the highest survivability for Bacillus sp. compared to Lactobacillus sp. in simulated gastric pH, and it was found to be maximum for B. inaquosorum KNUAS016 (8.25 ± 0.08 log10 CFU/mL) and minimum for L. sakei KNUAS019 (0.8 ± 0.02 log10 CFU/mL) at 3 h of incubation. Furthermore, B. inaquosorum KNUAS016 and L. brevis KNUAS017 also had the highest survival rates of 6.86 ± 0.02 and 5.37 ± 0.01 log10 CFU/mL, respectively, in a simulated intestinal fluid condition at 4 h of incubation. The percentage of autoaggregation at 6 h for L. sakei KNUAS019 (66.55 ± 0.33%), B. tequilensis KNUAS015 (64.56 ± 0.14%), and B. inaquosorum KNUAS016 (61.63 ± 0.19%) was >60%, whereas it was lower for L. brevis KNUAS017 (29.98 ± 0.09%). Additionally, B. subtilis KNUAS003 showed higher coaggregation at 63.84 ± 0.19% while B. proteolyticus KNUAS001 found at 30.02 ± 0.33%. Among them, Lactobacillus sp. showed the best non-hemolytic activity. The highest DPPH and ABTS radical scavenging activity was observed in L. sakei KNUAS019 (58.25% and 71.88%). The cell-free supernatant of Lactobacillus sp. considerably inhibited pathogenic growth, while the cell-free supernatant of Bacillus sp. was moderately inhibited when incubated for 24 h. However, the overall results found that B. subtilis KNUAS003, B. proteolyticus KNUAS012, L. brevis KNUAS017, L. graminis KNUAS018, and L. sakei KNUAS019 were recognized as potential probiotics through different functional and toxicity assessments.

Single cell transcriptomic analysis of the immune cell compartment in the human small intestine and in Celiac disease

Celiac disease is an autoimmune disorder in which ingestion of dietary gluten triggers an immune reaction in the small intestine leading to destruction of the lining epithelium. Current treatment focusses on lifelong adherence to a gluten-free diet. Gluten-specific CD4⁺ T cells and cytotoxic intraepithelial CD8⁺ T cells have been proposed to be central in disease pathogenesis. Here we use unbiased single-cell RNA-sequencing and explore the heterogeneity of CD45⁺ immune cells in the human small intestine. We show altered myeloid cell transcriptomes present in active celiac lesions. CD4⁺ and CD8⁺ T cells transcriptomes show extensive changes and we define a natural intraepithelial lymphocyte population that is reduced in celiac disease. We show that the immune landscape in Celiac patients on a gluten-free diet is only partially restored compared to control samples. Altogether, we provide a single cell transcriptomic resource that can inform the immune landscape of the small intestine during Celiac disease.

Celiac disease is linked to responsiveness to dietary gluten, which manifests itself as immune cell activation and the immunopathology including destruction of the epithelium of the small intestine. Here the authors apply single cell transcriptomics to characterise the immune cell compartment of the human small intestine during active Celiac disease.

Gastrointestinal Tract Microbiome Effect and Role in Disease Development

In recent years, it has been shown that gastrointestinal microflora has a substantial impact on the development of a large number of chronic diseases. The imbalance in the number or type of microbes in the gastrointestinal tract can lead to diseases and conditions, including autism spectrum disorder, celiac disease, Crohn’s disease, diabetes, and small bowel cancers. This can occur as a result of genetics, alcohol, tobacco, chemotherapeutics, cytostatics, as well as antibiotic overuse. Due to this, essential taxa can be lost, and the host’s metabolism can be severely affected. A less known condition called small intestine bacterial overgrowth (SIBO) can be seen in patients who suffer from hypochlorhydria and small intestine cancers. It is characterized as a state in which the bacterial population in the small intestine exceeds 10⁵–10⁶ organisms/mL. The latest examination methods such as double-balloon enteroscopy and wireless capsule endoscopy have the potential to increase the accuracy and precision of diagnosis and provide better patient care. This review paper aims to summarize the effect of the gastrointestinal environment on chronic disease severity and the development of cancers.

The Gut Microbiota and Inflammatory Factors in Pediatric Appendicitis

Background. The study analyzed gut microflora’s composition and investigated the associations between the associations between gut dysbiosis and inflammatory indicators in pediatric patients with acute appendicitis. Methods. High-throughput sequencing and bioinformatics analysis were used to investigate the composition and diversity of gut microflora in 20 pediatric patients with acute appendicitis and 11 healthy children. Endpoints measured were operational taxonomic units (OTU) of gut microflora. The OTU and its abundance analysis, sample diversity analysis, principal component analysis of samples, differential analysis, and analysis of biomarkers were performed. Results. Overall fecal microbial richness and diversity were similar in patients and controls. Yet richness within the group of Bilophila, Eggerthella, Clostridium, Parvimonas, Megasphaera, Atopobium, Phascolarctobacterium, Adlercreutzia, Barnesiella, Klebsiella, Enterococcus, and Prevotella genera was higher in patients. Adlercreutzia was significantly positively correlated with IL-10, while the three other genera, comprising Klebsiella, Adlercreutzia, and Prevotella, were positively correlated with B cells level. Conclusion. Gut microbiome components are significantly different in pediatric patients with acute appendicitis and healthy children. The differential abundance of some genera is correlated with the production of inflammatory markers in appendicitis.

Adherence to Gluten-Free Diet Restores Alpha Diversity in Celiac People but the Microbiome Composition Is Different to Healthy People

Celiac disease (CD) is an autoimmune disease with the destruction of small intestinal villi, which occurs in genetically predisposed individuals. At the present moment, a gluten-free diet (GFD) is the only way to restore the functionality of gut mucosa. However, there is an open debate on the effects of long-term supplementation through a GFD, because some authors report an unbalance in microbial taxa composition. Methods: For microbiome analysis, fecal specimens were collected from 46 CD individuals in GFD for at least 2 years and 30 specimens from the healthy controls (HC). Data were analyzed using an ensemble of software packages: QIIME2, Coda-lasso, Clr-lasso, Selbal, PICRUSt2, ALDEx2, dissimilarity-overlap analysis, and dysbiosis detection tests. Results: The adherence to GFD restored the alpha biodiversity of the gut microbiota in celiac people but microbial composition at beta diversity resulted as different to HC. The microbial composition of the CD subjects was decreased in a number of taxa, namely Bifidobacterium longum and several belonging to Lachnospiraceae family, whereas Bacteroides genus was found to be more abundant. Predicted metabolic pathways among the CD bacterial communities revealed an important role in tetrapyrrole biosynthesis. Conclusions: CD patients in GFD had a non-dysbiotic microbial composition for the crude alpha diversity metrics. We found significant differences in beta diversity, in certain taxon, and pathways between subjects with inactive CD in GFD and controls. Collectively, our data may suggest the development of new GFD products by modulating the gut microbiota through diet, supplements of vitamins, and the addition of specific prebiotics.

Systematic approach to celiac disease: a comprehensive review for primary providers

Celiac disease is an immune-mediated illness to gluten exposure in genetically susceptible patients. It is characterized by chronic lymphocytic inflammation of the small bowel leading to villous atrophy and its associated complications. The global prevalence of celiac disease is increasing, due in part to improved screening tests and simplified diagnostic criteria. Novel therapies are being developed and include proteolytic enzymes, sequestering agents, and immunotherapies. A strict gluten-free diet, however, remains the mainstay of treatment. In this comprehensive review, we discuss the epidemiology, definitions, diagnosis, and treatment of celiac disease.

Citizen-science reveals changes in the oral microbiome in Spain through age and lifestyle factors

The relevance of the human oral microbiome to our understanding of human health has grown in recent years as microbiome studies continue to develop. Given the links of the oral cavity with the digestive, respiratory and circulatory systems, the composition of the oral microbiome is relevant beyond just oral health, impacting systemic processes across the body. However, we still have a very limited understanding about intrinsic and extrinsic factors that shape the composition of the healthy oral microbiome. Here, we followed a citizen-science approach to assess the relative impact on the oral microbiome of selected biological, social, and lifestyle factors in 1648 Spanish individuals. We found that the oral microbiome changes across age, with middle ages showing a more homogeneous composition, and older ages showing more diverse microbiomes with increased representation of typically low abundance taxa. By measuring differences within and between groups of individuals sharing a given parameter, we were able to assess the relative impact of different factors in driving specific microbial compositions. Chronic health disorders present in the analyzed population were the most impactful factors, followed by smoking and the presence of yeasts in the oral cavity. Finally, we corroborate findings in the literature that relatives tend to have more similar oral microbiomes, and show for the first time a similar effect for classmates. Multiple intrinsic and extrinsic factors jointly shape the oral microbiome. Comparative analysis of metabarcoding data from a large sample set allows us to disentangle the individual effects.

Influence of Gluten-Free Diet on Gut Microbiota Composition in Patients with Coeliac Disease: A Systematic Review

The aim of this study was to assess the changes in microbiota composition during a gluten-free diet (GFD) in coeliac disease (CD) patients. The systematic search followed databases such as PUBMED (MEDLINE), SCOPUS, WEB OF SCIENCE and EMBASE. Out of 843 initially screened papers, a total number of 13 research papers were included. A total of 212 patients with CD on GFD, in comparison to 174 healthy individuals and 176 untreated patients with CD, were examined. Analysis of the microbial community based primarily on faecal samples and duodenal biopsies. Bifidobacterium was noticed to be less abundant in the study group than in both control groups, while the abundance of Bacteroides was more numerous in the group of CD patients on GFD. Staphylococcaceae prevailed in untreated CD patients. Despite the fact that the GFD was not able to fully restore commensal microorganism abundance, the treatment was associated with the greater abundance of selected beneficial bacteria and lower presence of pathogenic bacteria associated with worsening of CD symptoms.

Gracilaria lemaneiformis polysaccharides alleviate colitis by modulating the gut microbiota and intestinal barrier in mice

Gracilaria lemaneiformis polysaccharide (GLP) has varieties of antioxidation, however, the therapeutic effects of GLP on ulcerative colitis (UC) and the potential mechanisms involved are still incomplete. In the study, the analysis of the ζ-potential, thermal, and morphology properties demonstrated that GLP was a negatively charged polymer, and had great thermostability and irregular network. Moreover, the GLP treatment has the effects of reducing the severity of colitis caused by dextran sulfate sodium by alleviating the colon damage of mice, and increasing the amount of short-chain fatty acids in the intestines, alleviating histopathological inflammation. The sequencing results and α-diversity analysis showed that GLP could improve biodiversity, restore the abundance of Bacteroidetes, and decrease the proportion of Firmicutes. The level of CCL-25 and CCR-9 were inhibited, CD40 and TGF-β1 were increased. In summary, GLP has potentiality to be utilized as a hopeful functional food to the UC patients.

Adherence to the Mediterranean diet is linked to reduced psychopathology in female celiac disease patients

Celiac disease (CD) is a chronic enteropathy, affecting approximately 1% of the population worldwide with a higher prevalence in women. Recent studies demonstrate that CD is associated with an increased prevalence of psychopathology. The present study was undertaken to investigate the relationship between adherence to the Mediterranean Diet (MD) and psychopathological symptoms among CD patients, since the MD is a physical and mental health protective dietary regimen, which can easily be rendered gluten-free. A total of 134 CD patients (28 males and 106 females) were included in the study. Psychopathology was evaluated with the Symptom Checklist-90-Revised (SCL-90-R), and MD adherence was calculated using the Mediterranean Dietary Serving Score (MDSS). As regards psychopathological symptoms, female patients presented with statistically significant higher depression and anxiety than males. The majority of patients (64.9%) had low adherence to the MD (MDSS <14) with a mean score of 9.44 ± 3.26 and 9.14 ± 3.07 for men and women, respectively, out of a total of 24 points. High MD adherence was observed in 35.7% of the male and 34.9% of the female patients, with a mean score of 16.40 ± 2.63 and 16.35 ± 2.12, respectively. Interestingly, MD adherence was inversely associated with the intensity of several psychopathological symptoms in female patients, which represented the majority of the sample. The results of the study underline the need to encourage CD patients to adapt to a Mediterranean-style GFD.

Minimal Gluten Exposure Alters Urinary Volatile Organic Compounds in Stable Coeliac Disease

Coeliac disease (CD) patients are distinguishable from healthy individuals via urinary volatile organic compounds (VOCs) analysis. We exposed 20 stable CD patients on gluten-free diet (GFDs) to a 14-day, 3 g/day gluten challenge (GCh), and assessed urinary VOC changes. A control cohort of 20 patients continued on GFD. Urine samples from Days 0, 7, 14, 28 and 56 were analysed using Lonestar FAIMS and Markes Gas Chromatography-Time of Flight-Mass Spectrometer (GC-TOF-MS). VOC signatures on D (day) 7-56 were compared with D0. Statistical analysis was performed using R. In GCh patients, FAIMS revealed significant VOC differences for all time points compared to D0. GC-TOF-MS revealed significant changes at D7 and D14 only. In control samples, FAIMS revealed significant differences at D7 only. GC-TOF-MS detected no significant differences. Chemical analysis via GC-MS-TOF revealed 12 chemicals with significantly altered intensities at D7 vs. D0 for GCh patients. The alterations persisted for six chemicals at D14 and one (N-methyltaurine) remained altered after D14. This low-dose, short-duration challenge was well tolerated. FAIMS and GC-TOF-MS detected VOC signature changes in CD patients when undergoing a minimal GCh. These findings suggest urinary VOCs could have a role in monitoring dietary compliance in CD patients.

Extracellular vesicle microRNAs in celiac disease patients under a gluten-free diet, and in lactose intolerant individuals

BACKGROUND

Celiac disease (CD) is an autoimmune disorder triggered by an abnormal immunological response to gluten ingestion and is associated with deregulated expression of cellular microRNAs (miRNAs) of the gut mucosa. It is frequently misdiagnosed as lactose intolerance (LI) due to symptom resemblance. Microvilli loss may be counteracted by a rigorous gluten-free diet (GFD).

AIMS

To identify altered extracellular vesicle miRNAs from plasma among CD patients on GFD (n=34), lactose intolerant individuals on restrictive diet (n=14) and controls (n=23), and to predict biological pathways in which these altered miRNAs may play a part.

METHODS

Five different small RNA samples of each group were pooled twice and then screened by new-generation sequencing. Four miRNAs were selected to be quantified by RT-qPCR in the entire sample.

RESULTS

The levels of four miRNAs - miR-99b-3p, miR-197-3p, miR-223-3p, and miR-374b-5p - differed between CD patients and controls (P<0.05). Apart from miR-223-3p, all these miRNAs tended to have altered levels also between LI and controls (P<0.10). The results for miR-99b-3p and miR-197-3p between CD and controls were confirmed by RT-qPCR, which also indicated different levels of miR-99b-3p and miR-374b-5p between CD-associated LI and LI (P<0.05).

CONCLUSIONS

These miRNAs may have targets that affect cell death, cell communication, adhesion, and inflammation modulation pathways. Hence, altered miRNA levels could be associated with CD-related aspects and gut mucosa recovery.

Intestinal Models for Personalized Medicine: from Conventional Models to Microfluidic Primary Intestine-on-a-chip

Intestinal dysfunction is frequently driven by abnormalities of specific genes, microbiota, or microenvironmental factors, which usually differ across individuals, as do intestinal physiology and pathology. Therefore, it's necessary to develop personalized therapeutic strategies, which are currently limited by the lack of a simulated intestine model. The mature human intestinal mucosa is covered by a single layer of columnar epithelial cells that are derived from intestinal stem cells (ISCs). The complexity of the organ dramatically increases the difficulty of faithfully mimicking in vivo microenvironments. However, a simulated intestine model will serve as an indispensable foundation for personalized drug screening. In this article, we review the advantages and disadvantages of conventional 2-dimensional models, intestinal organoid models, and current microfluidic intestine-on-a-chip (IOAC) models. The main technological strategies are summarized, and an advanced microfluidic primary IOAC model is proposed for personalized intestinal medicine. In this model, primary ISCs and the microbiome are isolated from individuals and co-cultured in a multi-channel microfluidic chip to establish a microengineered intestine device. The device can faithfully simulate in vivo fluidic flow, peristalsis-like motions, host-microbe crosstalk, and multi-cell type interactions. Moreover, the ISCs can be genetically edited before seeding, and monitoring sensors and post-analysis abilities can also be incorporated into the device to achieve high-throughput and rapid pharmaceutical studies. We also discuss the potential future applications and challenges of the microfluidic platform. The development of cell biology, biomaterials, and tissue engineering will drive the advancement of the simulated intestine, making a significant contribution to personalized medicine in the future. Graphical abstract The intestine is a primary organ for digestion, absorption, and metabolism, as well as a major site for the host-commensal microbiota interaction and mucosal immunity. The complexity of the organ dramatically increases the difficulty of faithfully mimicking in vivo microenvironments, though physiological 3-dimensional of the native small intestinal epithelial tissue has been well documented. An intestinal stem cells-based microfluidic intestine-on-a-chip model that faithfully simulate in vivo fluidic flow, peristalsis-like motions, host-microbe crosstalk, and multi-cell type interactions will make a significant contribution.

The Role of HLA in the Association between IgA Deficiency and Celiac Disease

Selective IgA deficiency (SIgAD) is the most frequent primary immune defect. Since SIgAD is not characterized by relevant infectious issues in most cases, it is often diagnosed during the diagnostic work up of several and different autoimmune disorders, which are associated with this primary immune defect. The genetic background of SIgAD is complex and three HLA haplotypes resulted to be more frequently associated with it; in detail, two of them include HLA-DQB1^∗02 allelic variants, which are essential predisposing factors to develop Celiac Disease (CD). Here, we discuss the evidence regarding the role of HLA in the etiopathogenesis of SIgAD and its association with CD. Actually, the HLA region seems to play a modest role in the genetic predisposition to SIgAD and we may speculate that the association with the HLA-DQB1^∗02 alleles (or haplotypes including them) could derive from its link with CD. Indeed, SIgAD and some related immunological alterations are likely to predispose to several autoimmune diseases (with and despite different HLA backgrounds), including CD, which is relatively common and directly associated with the HLA-DQB1^∗02 allelic variants coding the DQ2 heterodimer. Further and specific studies are needed to make final conclusions in this regard.