Dietary antioxidant micronutrients alter mucosal inflammatory risk in a murine model of genetic and microbial susceptibility

The role of goblet cells in Crohn' s disease

The prevalence of Crohn's disease (CD), a subtype of inflammatory bowel disease (IBD), is increasing worldwide. The pathogenesis of CD is hypothesized to be related to environmental, genetic, immunological, and bacterial factors. Current studies have indicated that intestinal epithelial cells, including columnar, Paneth, M, tuft, and goblet cells dysfunctions, are strongly associated with these pathogenic factors. In particular, goblet cells dysfunctions have been shown to be related to CD pathogenesis by direct or indirect ways, according to the emerging studies. The mucus barrier was established with the help of mucins secreted by goblet cells. Not only do the mucins mediate the mucus barrier permeability and bacterium selection, but also, they are closely linked with the endothelial reticulum stress during the synthesis process. Goblet cells also play a vital role in immune response. It was indicated that goblet cells take part in the antigen presentation and cytokines secretion process. Disrupted goblet cells related immune process were widely discovered in CD patients. Meanwhile, dysbiosis of commensal and pathogenic microbiota can induce myriad immune responses through mucus and goblet cell-associated antigen passage. Microbiome dysbiosis lead to inflammatory reaction against pathogenic bacteria and abnormal tolerogenic response. All these three pathways, including the loss of mucus barrier function, abnormal immune reaction, and microbiome dysbiosis, may have independent or cooperative effect on the CD pathogenesis. However, many of the specific mechanisms underlying these pathways remain unclear. Based on the current understandings of goblet cell's role in CD pathogenesis, substances including butyrate, PPARγagonist, Farnesoid X receptor agonist, nuclear factor-Kappa B, nitrate, cytokines mediators, dietary and nutrient therapies were all found to have potential therapeutic effects on CD by regulating the goblet cells mediated pathways. Several monoclonal antibodies already in use for the treatment of CD in the clinical settings were also found to have some goblet cells related therapeutic targets. In this review, we introduce the disease-related functions of goblet cells, their relationship with CD, their possible mechanisms, and current CD treatments targeting goblet cells.

Oral administration of Lactobacillus casei DG® after ileostomy closure in restorative proctocolectomy: a randomized placebo-controlled trial (microbiota and immune microenvironment in pouchitis -MEP1)

Pouchitis is an idiopathic inflammatory disease that may occur in ileal pouches, and it can lead to ileal pouch failure. This was a single-center, randomized, double-blinded, placebo-controlled trial that assessed the effect of Lactobacillus casei (L. casei) DG®, a probiotic strain, on the ileal pouch mucosa to determine the crosstalk between microbiota and mucosal immune system. Fifty-two patients undergoing restorative proctocolectomy were recruited and randomly assigned to receive a daily oral supplementation of L. casei DG® (n = 26) or placebo (n = 26) for 8 weeks from the ileostomy closure (T0) to a pouch endoscopy after 8 weeks (T1) and 1 year (T2). Ileal pouch mucosa samples were collected at T0, T1, and T2. At T1, the L. casei DG®-supplemented group showed a significant reduction of inflammatory cytokines levels compared to T0 baseline levels in the pouch mucosa, whereas in the placebo group cytokines levels resulted stable. In conclusion, probiotic manipulation of mucosal microbiota by L. casei DG®-supplementation after stoma closure in patients who underwent restorative proctocolectomy has a beneficial impact on the ileal pouch microenvironment. Registration number: NCT03136419 (http://www.clinicaltrials.gov).

Houttuynia cordata thunb. alleviates inflammatory bowel disease by modulating intestinal microenvironment: a research review

Inflammatory bowel disease (IBD) is a complex group of chronic intestinal diseases, the cause of which has not yet been clarified, but it is widely believed that the disorder of the intestinal microenvironment and its related functional changes are key factors in the development of the disease. Houttuynia cordata thunb. is a traditional plant with abundant resources and long history of utilization in China, which has attracted widespread attention in recent years due to its potential in the treatment of IBD. However, its development and utilization are limited owing to the aristolochic acid alkaloids contained in it. Therefore, based on the relationship between the intestinal microenvironment and IBD, this article summarizes the potential mechanisms by which the main active ingredients of Houttuynia cordata thunb., such as volatile oils, polysaccharides, and flavonoids, and related traditional Chinese medicine preparations, such as Xiezhuo Jiedu Formula, alleviate IBD by regulating the intestinal microenvironment. At the same time, combined with current reports, the medicinal and edible safety of Houttuynia cordata thunb. is explained for providing ideas for further research and development of Houttuynia chordate thunb. in IBD disease, more treatment options for IBD patients, and more insights into the therapeutic potential of plants with homology of medicine and food in intestinal diseases, and even more diseases.

β-Glucan alleviates mice with ulcerative colitis through interactions between gut microbes and amino acids metabolism

BACKGROUND

Food polysaccharide 1,3-β-d-glucan (OBG) has been shown to alleviate ulcerative colitis (UC) in a mouse model, but the underlying mechanisms remain unclear. Here, we aimed to investigate potential mechanisms involving interactions among gut microbiota, microbial metabolites and host metabolic function.

RESULTS

OBG alleviated colonic inflammation, barrier dysfunction and intestinal concentrations of short-chain fatty acids in mice with UC. In addition, the relative abundance of Muribaculaceae, Alistipes, Erysipelatoclostridium and Blautia increased, whereas the abundance of Proteus, Lachnospiraceae and Ruminococcus decreased within the gut microbiota upon OBG treatment. Kyoto Encyclopedia of Genes and Genomes analyses showed that intestinal enzymes altered upon OBG treatment were mainly enriched in sub-pathways of amino acid biosynthesis. Metabolomics analyses showed that l-tryptophan, l-tyrosine, l-phenylalanine and l-alanine increased, which is consistent with the predictive metabolism of gut microbiota. Correlation analysis and interaction networks highlighted gut microbiota (especially Lactobacillus, Parabacteroides, Proteus and Blautia), metabolites (especially l-phenylalanine, l-tryptophan, l-tyrosine and acetic acid) and metabolism (phenylalanine, tyrosine and tryptophan biosynthesis) that may be key targets of OBG.

CONCLUSION

OBG is beneficial to the gut microecological balance in mice with colitis, mainly becaue of its impact on the interactions between gut microbes and amino acids metabolism (especially tyrosine and tryptophan metabolism). © 2022 Society of Chemical Industry.

The microbiome as a major function of the gastrointestinal tract and its implication in micronutrient metabolism and chronic diseases

The composition and function of microbes harbored in the human gastrointestinal lumen have been underestimated for centuries because of the underdevelopment of nucleotide sequencing techniques and the lack of humanized gnotobiotic models. Now, we appreciate that the gut microbiome is an integral part of the human body and exerts considerable roles in host health and diseases. Dietary factors can induce changes in the microbial community composition, metabolism, and function, thereby altering the host immune response, and consequently, may influence disease risks. An imbalance of gut microbiome homeostasis (i.e., dysbiosis) has been linked to several chronic diseases, such as inflammatory bowel diseases, obesity, and diabetes. Remarkable progress has recently been made in better understanding the extent to which the influence of the diet-microbiota interaction on host health outcomes in both animal models and human participants. However, the exact causality of the gut microbiome on the development of diseases is still controversial. In this review, we will briefly describe the general structure and function of the intestine and the process of nutrient absorption in humans. This is followed by a summarization of the recent updates on interactions between gut microbiota and individual micronutrients, including carotenoids, vitamin A, vitamin D, vitamin C, folate, iron, and zinc. In the opinion of the authors, these nutrients were identified as representative of vitamins and minerals with sufficient research on their roles in the microbiome. The host responses to the gut microbiome will also be discussed. Future direction in microbiome research, for example, precision microbiome, will be proposed.

Ameliorating Effects of Vitamin K2 on Dextran Sulfate Sodium-Induced Ulcerative Colitis in Mice

Ulcerative colitis (UC) is a chronic recurrent inflammatory illness of the gastrointestinal system. The purpose of this study was to explore the alleviating effect of vitamin K2 (VK2) on UC, as well as its mechanism. C57BL/6J mice were given 3% DSS for seven days to establish UC, and they then received VK2 (15, 30, or 60 mg/kg·bw) and 5-aminosalicylic acid (100 mg/kg·bw) for two weeks. We recorded the clinical signs, body weights, colon lengths, and histological changes during the experiment. We detected the inflammatory factor expressions using enzyme-linked immunosorbent assay (ELISA) kits, and we detected the tight junction proteins using Western blotting. We analyzed the intestinal microbiota alterations and short-chain fatty acids (SCFAs) using 16S rRNA sequencing and targeted metabolomics. According to the results, VK2 restored the colon lengths, improved the colonic histopathology, reduced the levels of proinflammatory cytokines (such as IL-1β, TNF-α, and IL-6), and boosted the level of the immunosuppressive cytokine IL-10 in the colon tissues of the colitis mice. Moreover, VK2 promoted the expression of mucin and tight junction proteins (such as occludin and zonula occludens-1) in order to preserve the intestinal mucosal barrier function and prevent UC in mice. Additionally, after the VK2 intervention, the SCFAs and SCFA-producing genera, such as Eubacterium_ruminantium_group and Faecalibaculum, were elevated in the colon. In conclusion, VK2 alleviated the DSS-induced colitis in the mice, perhaps by boosting the dominant intestinal microflora, such as Faecalibaculum, by reducing intestinal microflora dysbiosis, and by modulating the expression of SCFAs, inflammatory factors, and intestinal barrier proteins.

Role of metabolites derived from gut microbiota in inflammatory bowel disease

Over the past two decades, it is improved gut microbiota plays an important role in the health and disease pathogenesis. Metabolites, small molecules produced as intermediate or end products of microbial metabolism, is considered as one of the major interaction way for gut microbiota with the host. Bacterial metabolisms of dietary substrates, modification of host molecules or bacteria are the major source of metabolites. Signals from microbial metabolites affect immune maturation and homeostasis, host energy metabolism as well as mucosal integrity maintenance. Based on many researches, the composition and function of the microbiota can be changed, which is also seen in the metabolite profiles of patients with inflammatory bowel disease (IBD). Additionally, some specific classes of metabolites also can trigger IBD. In this paper, definition of the key classes of microbial-derived metabolites which are changed in IBD, description of the pathophysiological basis of association and identification of the precision therapeutic modulation in the future are the major contents.

Role of metabolites derived from gut microbiota in inflammatory bowel disease

Over the past two decades, it is improved gut microbiota plays an important role in the health and disease pathogenesis. Metabolites, small molecules produced as intermediate or end products of microbial metabolism, is considered as one of the major interaction way for gut microbiota with the host. Bacterial metabolisms of dietary substrates, modification of host molecules or bacteria are the major source of metabolites. Signals from microbial metabolites affect immune maturation and homeostasis, host energy metabolism as well as mucosal integrity maintenance. Based on many researches, the composition and function of the microbiota can be changed, which is also seen in the metabolite profiles of patients with inflammatory bowel disease (IBD). Additionally, some specific classes of metabolites also can trigger IBD. In this paper, definition of the key classes of microbial-derived metabolites which are changed in IBD, description of the pathophysiological basis of association and identification of the precision therapeutic modulation in the future are the major contents.

The Relieving Effects of a Polyherb-Based Dietary Supplement ColonVita on Gastrointestinal Quality of Life Index (GIQLI) in Older Adults with Chronic Gastrointestinal Symptoms Are Influenced by Age and Cardiovascular Disease: A 12-Week Randomized Placebo-Controlled Trial

Chronic gastrointestinal symptoms (CGS) negatively affect the quality of life in about 15–30% of the population without effective drugs. Recent studies suggest that dietary supplement may improve CGS, but inconsistent results exist. The goal of this study is to evaluate the effect of a polyherbal-based supplement ColonVita on the gastrointestinal quality of life index (GIQLI) in 100 old adults with CGS (63.1 ± 9.6 years) who were randomly assigned to daily ColonVita or placebo tablets (n = 50/group) for 12 weeks in a double-blind, randomized controlled trial design. No significant fibrdifferences were found between ColonVita and placebo in the baseline total GIQLI score (101.12 ± 16.87 vs. 101.80 ± 16.48) (P > 0.05) or postintervention total GIQLI score (114.78 ± 9.62 vs. 111.74 ± 13.01) (P > 0.05). However, ColonVita significantly improved 16 scores of the 19 core GI symptoms compared with 10 items improved by placebo. The ColonVita group significantly improved the remission rate of 5 core GI symptoms compared to placebo and significantly improved the total GIQLI scores (118.09 ± 7.88 vs. 109.50 ± 16.71) (P < 0.05) and core GI symptom scores (64.61 ± 3.99 vs. 60.00 ± 8.65) (P < 0.05) in people ≥60 years of age (n = 49) but not in those under 60 y (n = 51). ColonVita significantly improved the total GIQLI scores and core GI symptom scores in people without cardiovascular diseases (CVD) (n = 56) (116.74 ± 9.38 vs. 110.10 ± 14.28) (P < 0.05) and (63.11 ± 4.53 vs. 59.93 ± 8.03) (P=0.07), respectively, but not in those with CVD (n = 44). Thus, ColonVita was beneficial for old adults with CGS, especially those ≥60 years of age and without CVD. Because a heterogenous pathogenesis of CGS-like irritable bowel syndrome (IBS) and inflammatory bowel disease (ISD) is differentially associated with CVD, different comorbidities may have influenced the outcomes of different trials that should be controlled in further studies.

In-depth analysis of the mechanisms of aloe polysaccharides on mitigating subacute colitis in mice via microbiota informatics

Aloe polysaccharides (APs) are indigestible bioactive polysaccharides, while can be fermented by colonic microbiota. Although plant polysaccharides can alleviate subacute ulcerative colitis (SUC), the mechanisms APs regulated SUC via colonic microbiota have not been fully explored. Hence, to elucidate the complex interactions between the novel APs, colonic microbiota, SCFAs, and inflammation, the SUC mouse model and in-depth analysis were performed, including multiple bioinformatics analysis and structural equation modeling (SEM). After APs intervention, SCFAs and SCFAs-producing genus, including Akkermansia and Blautia, were increased in colon, and the colonic inflammation and barrier dysfunction were alleviated significantly in SUC mice. Spearman analysis found positive correlations between microbiota and SCFAs. PICRUSt2 and KEGG analysis revealed 6-pyruvoyltetra hydropterin synthase in folate biosynthesis metabolism pathway was activated, while phosphotransferase system was inhibited. SEM results further proved APs was beneficial to gut micro-ecological balance in mice via SCFAs metabolism and anti-inflammatory functions. Together, APs could be exploited to alleviate SUC as dietary therapeutics.

Aloe polysaccharides ameliorate acute colitis in mice via Nrf2/HO-1 signaling pathway and short-chain fatty acids metabolism

Aloe polysaccharides (APs) are acetyl polysaccharides. It has been reported APs could protect mice from ulcerative colitis (UC), but the complex interactions between APs and the intestinal barrier were unclear. Here, we investigated the relationship between APs and UC, and determined the synergistic effects of Nrf2/HO-1 signaling pathway and short-chain fatty acids (SCFAs) metabolism on protecting intestinal barrier in acute UC mice. Results showed APs could scavenge free radicals in vitro. In vivo, APs had the antioxidant and anti-inflammatory effect both in serum and colon. Besides, the pathological results showed APs could alleviate colonic lesions. Furthermore, our study indicated treatment with APs effectively increased SCFAs production. The inhibition of acute UC in mice was correlated with the APs-mediated effects on improving the expression of ZO-1, occludin, Nrf2, HO-I, and NQO1. Thus, APs effectively promoted the intestinal barrier via Nrf2/HO-1 signaling pathway and SCFAs metabolism, effectively ameliorating acute colitis in mice.

The Life-Long Role of Nutrition on the Gut Microbiome and Gastrointestinal Disease

Bacterial colonization of the intestines occurs during the first 2 years of life. Homeostasis of the gut microbiome is established to foster normal intestinal immune development for adulthood. Derangements in this process can interfere with immune function and increase an individual's risk for gastrointestinal disorders. We discuss the role of diet and the microbiome on the onset of such disorders. We examine how micronutrients, prebiotics, and probiotics modulate disease pathogenesis. We discuss how diet and abnormal microbial colonization impact extraintestinal organs. Understanding the communication of nutrition and the microbiome offers exciting opportunities for therapeutics.

Gut Microbiota Dysbiosis-Immune Hyperresponse-Inflammation Triad in Coronavirus Disease 2019 (COVID-19): Impact of Pharmacological and Nutraceutical Approaches

Coronavirus Disease 2019 (COVID-19) is a pandemic infection caused by a novel coronavirus named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Patients present a complex clinical picture that, in severe cases, evolves to respiratory, hepatic, gastrointestinal, and neurological complications, and eventually death. The underlying pathophysiological mechanisms are complex and multifactorial and have been summarized as a hyperresponse of the immune system that originates an inflammatory/cytokine storm. In elderly patients, particularly in those with pre-existing cardiovascular, metabolic, renal, and pulmonary disorders, the disease is particularly severe, causing prolonged hospitalization at intensive care units (ICU) and an increased mortality rate. Curiously, the same populations have been described as more prone to a gut microbiota (GM) dysbiosis profile. Intestinal microflora plays a major role in many metabolic and immune functions of the host, including to educate and strengthen the immune system to fight infections, namely of viral origin. Notably, recent studies suggest the existence of GM dysbiosis in COVID-19 patients. This review article highlights the interplay between the triad GM dysbiosis-immune hyperresponse-inflammation in the individual resilience/fragility to SARS-CoV-2 infection and presents the putative impact of pharmacological and nutraceutical approaches on the triumvirate, with focus on GM.

Role of Dietary Nutrients in the Modulation of Gut Microbiota: A Narrative Review

Understanding how dietary nutrients modulate the gut microbiome is of great interest for the development of food products and eating patterns for combatting the global burden of non-communicable diseases. In this narrative review we assess scientific studies published from 2005 to 2019 that evaluated the effect of micro- and macro-nutrients on the composition of the gut microbiome using in vitro and in vivo models, and human clinical trials. The clinical evidence for micronutrients is less clear and generally lacking. However, preclinical evidence suggests that red wine- and tea-derived polyphenols and vitamin D can modulate potentially beneficial bacteria. Current research shows consistent clinical evidence that dietary fibers, including arabinoxylans, galacto-oligosaccharides, inulin, and oligofructose, promote a range of beneficial bacteria and suppress potentially detrimental species. The preclinical evidence suggests that both the quantity and type of fat modulate both beneficial and potentially detrimental microbes, as well as the Firmicutes/Bacteroides ratio in the gut. Clinical and preclinical studies suggest that the type and amount of proteins in the diet has substantial and differential effects on the gut microbiota. Further clinical investigation of the effect of micronutrients and macronutrients on the microbiome and metabolome is warranted, along with understanding how this influences host health.

The relationship between vitamin C status, the gut-liver axis, and metabolic syndrome

Metabolic syndrome (MetS) is a constellation of cardiometabolic risk factors, which together predict increased risk of more serious chronic diseases. We propose that one consequence of dietary overnutrition is increased abundance of Gram-negative bacteria in the gut that cause increased inflammation, impaired gut function, and endotoxemia that further dysregulate the already compromised antioxidant vitamin status in MetS. This discussion is timely because "healthy" individuals are no longer the societal norm and specialized dietary requirements are needed for the growing prevalence of MetS. Further, these lines of evidence provide the foundational basis for investigation that poor vitamin C status promotes endotoxemia, leading to metabolic dysfunction that impairs vitamin E trafficking through a mechanism involving the gut-liver axis. This report will establish a critical need for translational research aimed at validating therapeutic approaches to manage endotoxemia-an early, but inflammation-inducing phenomenon, which not only occurs in MetS, but is also prognostic of more advanced metabolic disorders including type 2 diabetes mellitus, as well as the increasing severity of nonalcoholic fatty liver diseases.

The Role of Diet, Micronutrients and the Gut Microbiota in Age-Related Macular Degeneration: New Perspectives from the Gut⁻Retina Axis

Age-related macular degeneration (AMD) is a complex multifactorial disease and the primary cause of legal and irreversible blindness among individuals aged ≥65 years in developed countries. Globally, it affects 30–50 million individuals, with an estimated increase of approximately 200 million by 2020 and approximately 300 million by 2040. Currently, the neovascular form may be able to be treated with the use of anti-VEGF drugs, while no effective treatments are available for the dry form. Many studies, such as the randomized controlled trials (RCTs) Age-Related Eye Disease Study (AREDS) and AREDS 2, have shown a potential role of micronutrient supplementation in lowering the risk of progression of the early stages of AMD. Recently, low-grade inflammation, sustained by dysbiosis and a leaky gut, has been shown to contribute to the development of AMD. Given the ascertained influence of the gut microbiota in systemic low-grade inflammation and its potential modulation by macro- and micro-nutrients, a potential role of diet in AMD has been proposed. This review discusses the role of the gut microbiota in the development of AMD. Using PubMed, Web of Science and Scopus, we searched for recent scientific evidence discussing the impact of dietary habits (high-fat and high-glucose or -fructose diets), micronutrients (vitamins C, E, and D, zinc, beta-carotene, lutein and zeaxanthin) and omega-3 fatty acids on the modulation of the gut microbiota and their relationship with AMD risk and progression.

Data on changes to mucosal inflammation and the intestinal microbiota following dietary micronutrients in genetically susceptible hosts

These data support the findings that dietary micronutrients influence the inflammatory responses and intestinal microbial community structure and function in a model of pouchitis-like small bowel inflammation reported in “Dietary Antioxidant Micronutrients Alter Mucosal Inflammatory Risk in a Murine Model of Genetic and Microbial Susceptibility” (Pierre et al., 2018) [1]. Briefly, wild-type and IL-10 deficient mice underwent surgical placement of small intestinal self-filling loops (SFL) and were subsequently fed purified control diet (CONT) or control diet supplemented with 4 micronutrients (AOX), retinoic acid, Vitamin C, Vitamin E, and selenium, for 14 days. These data include changes in host markers, such as body weight, mucosal levels of myeloperoxidase and syndecan-1, and luminal IgA and IgG levels. These data also include changes in the microbial compartment, including 16S community structure in the self-filling loop, conventionalized germ-free mice, and microbial substrate preference performed through anaerobic bacterial culturing of SLF CONT and AOX microbiota.