• Journal of Yeungnam Medical Science
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• 제38권1호
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• pp.27-33
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• 2021

The gut is a complex organ that has played an important role in digestion, absorption, endocrine functions, and immunity. The gut mucosal barriers consist of the immunologic barrier and nonimmunologic barrier. During critical illnesses, the gut is susceptible to injury due to the induction of intestinal hyperpermeability. Gut hyperpermeability and barrier dysfunction may lead to systemic inflammatory response syndrome. Additionally, gut microbiota are altered during critical illnesses. The etiology of such microbiome alterations in critical illnesses is multifactorial. The interaction or systemic host defense modulation between distant organs and the gut microbiome is increasingly studied in disease research. No treatment modality exists to significantly enhance the gut epithelial integrity, permeability, or mucus layer in critically ill patients. However, multiple helpful approaches including clinical and preclinical strategies exist. Enteral nutrition is associated with an increased mucosal barrier in animal and human studies. The trophic effects of enteral nutrition might help to maintain the intestinal physiology, prevent atrophy of gut villi, reduce intestinal permeability, and protect against ischemia-reperfusion injury. The microbiome approach such as the use of probiotics, fecal microbial transplantation, and selective decontamination of the digestive tract has been suggested. However, its evidence does not have a high quality. To promote rapid hypertrophy of the small bowel, various factors have been reported, including the epidermal growth factor, membrane permeant inhibitor of myosin light chain kinase, mucus surrogate, pharmacologic vagus nerve agonist, immune-enhancing diet, and glucagon-like peptide-2 as preclinical strategies. However, the evidence remains unclear.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제19권4호
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• pp.221-228
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• 2016

The gastrointestinal exposome represents the integration of all xenobiotic components and host-derived endogenous components affecting the host health, disease progression and ultimately clinical outcomes during the lifespan. The human gut microbiome as a dynamic exposome of commensalism continuously interacts with other exogenous exposome as well as host sentineling components including the immune and neuroendocrine circuit. The composition and diversity of the microbiome are established on the basis of the luminal environment (physical, chemical and biological exposome) and host surveillance at each part of the gastrointestinal lining. Whereas the chemical exposome derived from nutrients and other xenobiotics can influence the dynamics of microbiome community (the stability, diversity, or resilience), the microbiomes reciprocally alter the bioavailability and activities of the chemical exposome in the mucosa. In particular, xenobiotic metabolites by the gut microbial enzymes can be either beneficial or detrimental to the host health although xenobiotics can alter the composition and diversity of the gut microbiome. The integration of the mucosal crosstalk in the exposome determines the fate of microbiome community and host response to the etiologic factors of disease. Therefore, the network between microbiome and other mucosal exposome would provide new insights into the clinical intervention against the mucosal or systemic disorders via regulation of the gut-associated immunological, metabolic, or neuroendocrine system.

• BMB Reports
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• 제49권5호
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• pp.263-269
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• 2016

The intestine represents the largest and most elaborate immune system organ, in which dynamic and reciprocal interplay among numerous immune and epithelial cells, commensal microbiota, and external antigens contributes to establishing both homeostatic and pathologic conditions. The mechanisms that sustain gut homeostasis are pivotal in maintaining gut health in the harsh environment of the gut lumen. Intestinal epithelial cells are critical players in creating the mucosal platform for interplay between host immune cells and luminal stress inducers. Thus, knowledge of the epithelial interface between immune cells and the luminal environment is a prerequisite for a better understanding of gut homeostasis and pathophysiologies such as inflammation. In this review, we explore the importance of the epithelium in limiting or promoting gut inflammation (e.g., inflammatory bowel disease). We also introduce recent findings on how small RNAs such as microRNAs orchestrate pathophysiologic gene regulation.

• Journal of Applied Biological Chemistry
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• 제62권2호
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• pp.211-217
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• 2019

Dietary pattern has paramount importance in shaping the gut microbiota and its associated host health. Herein this study, long term (12 weeks) impact of mushroom derived dietary fiber, ${\beta}-glucan$, is investigated for its effect on low fiber diet consumption. Inclusion of dietary fiber into the low fiber diet (LFD) increased the abundance of genera Lactobacillus and Anaerostipes, the microbes responsible for butyrate (major 'fuel source' of colonocytes) production. Mice fed LFD with ${\beta}-glucan$ showed significant increase in the length of small intestine compared to that of the LFD group without ${\beta}-glucan$. Further, dietary fiber consumption enhanced goblet cell density along with mucosal layer thickness. These results indicate promising effects of ${\beta}-glucan$ towards maintenance of healthy gut and gut microbiota.

• Journal of Microbiology and Biotechnology
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• 제21권2호
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• pp.197-203
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• 2011

Lactobacilli are normal constituents of the intestinal microbiota, and some strains show the capacity to bind to extracellular matrix proteins and components of the mucosal layer, which represents an adaptation to persist in this niche. A shotgun phage-display library of Lactobacillus casei BL23 was constructed and screened for peptides able to bind to fibronectin and collagen. Clones showing binding to these proteins were isolated, which encoded overlapping fragments of a putative transcriptional regulator (LCABL_29260), a hypothetical protein exclusively found in the L. casei/rhamnosus group (LCABL_01820), and a putative phage-related endolysin (LCABL_13470). The construction of different glutathione S-transferase (GST) fusions confirmed the binding activity and demonstrated that the three identified proteins could interact with fibronectin, fibrinogen, and collagen. The results illustrate the utility of phage display for the isolation of putative adhesins in lactobacilli. However, it remains to be determined whether the primary function of these proteins actually is adhesion to mucosal surfaces.

• International Journal of Oral Biology
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• 제42권3호
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• pp.123-128
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• 2017

Recurrent aphthous stomatitis (RAS) is a common oral mucosal disorder for which no curative treatment is available. We previously reported that decreased Streptococcus salivarius and increased Acinetobacter johnsonii on the oral mucosa are associated with RAS risk. The purpose of this study was to identify antibiotics that selectively inhibit A. johnsonii but minimally inhibit oral mucosal commensals. S. salivarius KCTC 5512, S. salivarius KCTC 3960, A. johnsonii KCTC 12405, Rothia mucilaginosa KCTC 19862, and Veillonella dispar KCOM 1864 were subjected to antibiotic susceptibility test using amoxicillin, cefotaxime, gentamicin, clindamycin, and metronidazole in liquid culture. The minimal inhibitory concentration (MIC) was defined as the concentration that inhibits 90% of growth. Only gentamicin presented a higher MIC for A. johnsonii than MICs for S. salivarius and several oral mucosal commensals. Interestingly, the growth of S. salivarius increased 10~200% in the presence of sub-MIC concentrations of gentamicin, which was independent of development of resistance to gentamicin. In conclusion, gentamicin may be useful to restore RAS-associated imbalance in oral microbiota by selectively inhibiting the growth of A. johnsonii but enhancing the growth of S. salivarius.

• The Korean journal of internal medicine
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• 제39권4호
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• pp.590-602
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• 2024

Background/Aims: Recent research has increasingly focused on the role of the gastric microbiome in the development of gastric cancer. We aimed to investigate the changes in the microbiome during gastric carcinogenesis in structural and functional aspects, with a specific focus on the association between oral and gastric microbiomes. Methods: We collected saliva, gastric juice, and gastric tissue samples from 141 patients at different stages of gastric carcinogenesis and processed them for microbiome analysis using 16S rRNA gene profiling. The alpha and beta diversities were analyzed, and the differences in microbiome composition and function profiles were analyzed among the groups, as well as the correlation between changes in the oral and gastric microbiomes during carcinogenesis. Results: We observed significant differences in microbial diversity and composition between the disease and control groups, primarily in the gastric juice. Specific bacterial strains, including Schaalia odontolytica, Streptococcus cristatus, and Peptostreptococcus stomatis, showed a significant increase in abundance in the gastric juice in the low-grade dysplasia and gastric cancer groups. Notably, the correlation between the oral and gastric microbiota compositions, increased as the disease progressed. Predictive analysis of the metagenomic functional profiles revealed changes in functional pathways that may be associated with carcinogenesis (ABC transport and two-component systems). Conclusions: During gastric carcinogenesis, the abundance of oral commensals associated with cancer increased in the stomach. The similarity in microbial composition between the stomach and oral cavity also increased, implying a potential role of oral-gastric bacterial interactions in gastric cancer development.

• Animal Bioscience
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• 제35권10호
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• pp.1461-1478
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• 2022

The maintenance of poultry gut health is complex depending on the intricate balance among diet, the commensal microbiota, and the mucosa, including the gut epithelium and the superimposing mucus layer. Changes in microflora composition and abundance can confer beneficial or detrimental effects on fowl. Antibiotics have devastating impacts on altering the landscape of gut microbiota, which further leads to antibiotic resistance or spread the pathogenic populations. By eliciting the landscape of gut microbiota, strategies should be made to break down the regulatory signals of pathogenic bacteria. The optional strategy of conferring dietary fibers (DFs) can be used to counterbalance the gut microbiota. DFs are the non-starch carbohydrates indigestible by host endogenous enzymes but can be fermented by symbiotic microbiota to produce short-chain fatty acids (SCFAs). This is one of the primary modes through which the gut microbiota interacts and communicate with the host. The majority of SCFAs are produced in the large intestine (particularly in the caecum), where they are taken up by the enterocytes or transported through portal vein circulation into the bloodstream. Recent shreds of evidence have elucidated that SCFAs affect the gut and modulate the tissues and organs either by activating G-protein-coupled receptors or affecting epigenetic modifications in the genome through inducing histone acetylase activities and inhibiting histone deacetylases. Thus, in this way, SCFAs vastly influence poultry health by promoting energy regulation, mucosal integrity, immune homeostasis, and immune maturation. In this review article, we will focus on DFs, which directly interact with gut microbes and lead to the production of SCFAs. Further, we will discuss the current molecular mechanisms of how SCFAs are generated, transported, and modulated the pro-and anti-inflammatory immune responses against pathogens and host physiology and gut health.

• 대한약침학회지
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• 제27권2호
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• pp.59-69
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• 2024

This study investigates the therapeutic potential of Indigo Naturalis (IN) in treating a Inflammatory Bowel Disease (IBD). The objective is to comprehensively examine the effects and pharmacological mechanisms of IN on IBD, assessing its potential as an novel treatment for IBD. Analysis of 11 selected papers is conducted to understand the effects of IN, focusing on compounds like indirubin, isatin, indigo, and tryptanthrin. This study evaluates their impact on Disease Activity Index (DAI) score, colon length, mucosal damage, and macrophage infiltration in Dextran Sulfate Sodium (DSS)-induced colitis mice. Additionally, It investigate into the anti-inflammatory mechanisms, including Aryl hydrocarbon Receptor (AhR) pathway activation, Nuclear Factor kappa B (NF-κB)/nod-like receptor family pyrin domain containing 3 (NLRP3)/Interleukin 1 beta (IL-1β) inhibition, and modulation of Toll-like receptor 4 (TLR4)/myeloid differentiation primary response 88 (MYD88)/NF-κB and Mitogen Activated Protein Kinase (MAPK) pathways. Immunomodulatory effects on T helper 17 (Th17)/regulatory T cell (Treg cell) balance and Glycogen synthase kinase-3 beta (GSK3-β) expression are also explored. Furthermore, the study addresses the role of IN in restoring intestinal microbiota diversity, reducing pathogenic bacteria, and increasing beneficial bacteria. The findings reveal that IN, particularly indirubin and indigo, demonstrates significant improvements in DAI score, colon length, mucosal damage, and macrophage infiltration in DSS-induced colitis mice. The anti-inflammatory effects are attributed to the activation of the AhR pathway, inhibition of inflammatory pathways, and modulation of immune responses. These results exhibit the potential of IN in IBD treatment. Notably, the restoration of intestinal microbiota diversity and balance further supports its efficacy. IN emerges as a promising and effective treatment for IBD, demonstrating anti-inflammatory effects and positive outcomes in preclinical studies. However, potential side effects necessitate further investigation for safe therapeutic development. The study underscores the need for future research to explore a broader range of active ingredients in IN to enhance therapeutic efficacy and safety.

• Clinical and Experimental Pediatrics
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• 제56권9호
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• pp.369-376
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• 2013

A complex interplay between genetic and environmental factors partially contributes to the development of allergic diseases by affecting development during prenatal and early life. To explain the dramatic increase in the prevalence of allergic diseases, the hygiene hypothesis proposed that early exposure to infection prevented allergic diseases. The hygiene hypothesis has changed to the microbial hypothesis, in which exposure to microbes is closely linked to the development of the early immune system and allergic diseases. The intestinal flora may contribute to allergic disease through its substantial effect on mucosal immunity. Based on findings that exposure to microbial flora early in life can change the Th1/Th2 balance, thus favoring a Th1 cell response, probiotics may be beneficial in preventing allergic diseases. However, evidence from clinical and basic research to prove the efficacy of probiotics in preventing allergy is lacking. To date, studies have yielded inconsistent findings on the usefulness of probiotics in allergic diseases. It is difficult to demonstrate an exact effect of probiotics on asthma, allergic rhinitis, and food allergy because of study limitations, such as different first supplementation period, duration, different strains, short follow-up period, and host factors. However, many studies have demonstrated a significant clinical improvement in atopic dermatitis with the use of probiotics. An accurate understanding of the development of human immunity, intestinal barrier function, intestinal microbiota, and systemic immunity is required to comprehend the effects of probiotics on allergic diseases.