Short Chain Fatty Acids (SCFAs)-Mediated Gut Epithelial and Immune Regulation and Its Relevance for Inflammatory Bowel Diseases

Emerging Frontiers in Microbiome Engineering

The gut microbiome has a significant impact on health and disease and can actively contribute to obesity, diabetes, inflammatory bowel disease, cardiovascular disease, and neurological disorders. We do not yet have the necessary tools to fine-tune the microbial communities that constitute the microbiome, though such tools could unlock extensive benefits to human health. Here, we provide an overview of the current state of technological tools that may be used for microbiome engineering. These tools can enable investigators to define the parameters of a healthy microbiome and to determine how gut bacteria may contribute to the etiology of a variety of diseases. These tools may also allow us to explore the exciting prospect of developing targeted therapies and personalized treatments for microbiome-linked diseases.

Probiotic Lactobacillus plantarum IS 10506 supplementation increase SCFA of women with functional constipation

BACKGROUND AND OBJECTIVES

Gut microbiota influences our health via multiple mechanisms. Microbiota produced Short Chain Fatty Acid (SCFA) as an energy to maintain gut ecosystem and physiology. Dysbiosis is correlated with SCFA imbalance which in turn resulted in physiological abnormalities in the intestine, such as functional constipation.

MATERIALS AND METHODS

Randomized Double-Blind Controlled Trial (RCT) was conducted on women with functional constipation (n=37) in the community of Jakarta and profile of SCFA was assessed by using GC-MS from the stool after 21 days supplementation of fermented milk (placebo and probiotic).

RESULTS

Probiotic supplementation significantly influenced acetate titer (p=0,032) marginally significant for propionate and butyrate (p=0.063 and p=0.068, respectively) and the respondent with increasing SCFA's metabolite are higher in probiotic group compared to the respondents in placebo group. Acetate is the highest SCFA titer found in faeces samples of women with functional constipation.

CONCLUSION

Probiotic Lactobacillus plantarum IS 10506 supplementation influenced all the SCFA parameter (acetate, propionate and butyrate).

Deletion of the Casp8 gene in mice results in ileocolitis, gut barrier dysfunction, and malassimilation, which can be partially attenuated by inulin or sodium butyrate

Genetically modified mice have been successfully used as models for inflammatory bowel diseases; however, dietary effects were poorly examined. Here, we studied the impact of particular nutrients and supplements on gut functions related to the knockout of the epithelial caspase-8 gene. Caspase-8 knockout (Casp8^∆IEC) and control (Casp8^fl) mice were fed for 4 wk a control diet (CD) enriched with 10% inulin (CD-Inu) or 5% sodium butyrate (CD-But) while having free access to plain water or water supplemented with 30% fructose (+F). Body weight changes, intestinal inflammation, and selected markers for barrier function and of liver steatosis were assessed. Casp8^∆IEC mice developed ileocolitis accompanied by changes in intestinal barrier morphology and reduced expression of barrier-related genes such as mucin-2 (Muc2) and defensins in the ileum and Muc2 in the colon. Casp8^∆IEC mice fed a CD also showed impaired body weight gain compared with Casp8^fl mice, which was even more pronounced in mice receiving water supplemented with fructose. Furthermore, we observed a marked liver steatosis and inflammation in some but not all Casp8^∆IEC mice under a CD, which was on average similar to that observed in control mice under a fructose-rich diet. Hepatic lipid accumulation, as well as markers of ileal barrier function, but not intestinal pathohistology or body weight loss, were attenuated by diets enriched with inulin or butyrate, especially in the absence of fructose supplementation. Our data show that ileocolitis, barrier dysfunction, and malassimilation in Caspase-8 knockout mice can be partially attenuated by oral inulin or butyrate supplementation.NEW & NOTEWORTHY Genetic mouse models for ileocolitis are important to understand inflammatory bowel disease in humans. We examined dietetic factors that might aggravate or attenuate ileocolitis and related pathologies in such a model. Deletion of the caspase-8 gene results not only in ileocolitis but also in gut barrier dysfunction, liver steatosis, and malassimilation, which can be partially attenuated by oral inulin or sodium butyrate. Our data indicate that diet modifications can contribute to disease variability and therapy.

Administration of Akkermansia muciniphila Ameliorates Dextran Sulfate Sodium-Induced Ulcerative Colitis in Mice

Inflammatory bowel diseases (IBDs) develop as a result of complex interactions among genes, innate immunity and environmental factors, which are related to the gut microbiota. Multiple clinical and animal data have shown that Akkermansia muciniphila is associated with a healthy mucosa. However, its precise role in colitis is currently unknown. Our study aimed to determine its protective effects and underlying mechanisms in a dextran sulfate sodium (DSS)-induced colitis mouse model. Twenty-four C57BL/6 male mice were administered A. muciniphila Muc^T or phosphate-buffered saline (PBS) once daily by oral gavage for 14 days. Colitis was induced by drinking 2% DSS from days 0 to 6, followed by 2 days of drinking normal water. Mice were weighed daily and then sacrificed on day 8. We found that A. muciniphila improved DSS-induced colitis, which was evidenced by reduced weight loss, colon length shortening and histopathology scores and enhanced barrier function. Serum and tissue levels of inflammatory cytokines and chemokines (TNF-α, IL1α, IL6, IL12A, MIP-1A, G-CSF, and KC) decreased as a result of A. muciniphila administration. Analysis of 16S rDNA sequences showed that A. muciniphila induced significant gut microbiota alterations. Furthermore, correlation analysis indicated that pro-inflammatory cytokines and other injury factors were negatively associated with Verrucomicrobia, Akkermansia, Ruminococcaceae, and Rikenellaceae, which were prominently abundant in A. muciniphila-treated mice. We confirmed that A. muciniphila treatment could ameliorate mucosal inflammation either via microbe-host interactions, which protect the gut barrier function and reduce the levels of inflammatory cytokines, or by improving the microbial community. Our findings suggest that A. muciniphila may be a potential probiotic agent for ameliorating colitis.

Chronic Unpredictable Mild Stress in Rats Induces Colonic Inflammation

Chronic psychological stress is associated with an increased risk for relapse of inflammatory bowel diseases (IBD) and impedes the treatment of this condition. However, the impact of stress on the risk of IBD onset remains unclear. The goal of the present study was to examine whether chronic unpredictable mild stress (CUMS) could initiate or aggravate the onset of colon inflammation in rats which, in turn, would be capable of triggering bowel disease. We found that CUMS exposure increased infiltration of CD-45 positive cells and MPO activity, as well as augmented the expression of the inflammatory cytokines, IFN-γ and IL-6 within the colon of these rats. In addition, CUMS treatment changed the composition and diversity of gut microbiota and enhanced intestinal epithelial permeability, indicating the presence of a defect in the intestinal barrier. This CUMS-induced disruption of mucosal barrier integrity was associated with a reduction in expression of the tight junction protein, occludin 1, and an inhibition in mucosal layer functioning via reductions in goblet cells. Results from bacterial cultures revealed an increased presence of bacterial invasion after CUMS treatment as compared with that observed in controls. Thus, our data indicate that CUMS treatment induces alterations of the fecal microbiome and intestinal barrier defects, which facilitates bacterial invasion into colonic mucosa and further exacerbates inflammatory reactions within the colon. Accordingly, chronic stress may predispose patients to gastrointestinal infection and increase the risk of inflammation-related gut diseases.

Microbiota and Immune-Mediated Skin Diseases-An Overview

In recent years, increased attention has been paid to the relationship between microbiota and various diseases, especially immune-mediated diseases. Because conventional therapy for many autoimmune diseases is limited both in efficacy and safety, there is an increased interest in identifying nutraceuticals, particularly probiotics, able to modulate the microbiota and ameliorate these diseases. In this review, we analyzed the research focused on the role of gut microbiota and skin in immunity, their role in immune-mediated skin diseases (IMSDs), and the beneficial effect of probiotics in patients with this pathology. We selected articles published between 2009 and 2019 in PubMed and ScienceDirect that provided information regarding microbiota, IMSDs and the role of probiotics in these diseases. We included results from different types of studies including observational and interventional clinical trials or in vivo and in vitro experimental studies. Our results showed that probiotics have a beneficial effect in changing the microbiota of patients with IMSDs; they also influence disease progression. Further studies are needed to better understand the impact of new therapies on intestinal microbiota. It is also important to determine whether the microbiota of patients with autoimmune diseases can be manipulated in order to restore homeostasis of the microbiota.

The Role of Gut Microbiota in Intestinal Inflammation with Respect to Diet and Extrinsic Stressors

The gut microbiota maintains a symbiotic relationship with the host and regulates several important functions including host metabolism, immunity, and intestinal barrier function. Intestinal inflammation and inflammatory bowel disease (IBD) are commonly associated with dysbiosis of the gut microbiota. Alterations in the gut microbiota and associated changes in metabolites as well as disruptions in the intestinal barrier are evidence of the relationship between the gut microbiota and intestinal inflammation. Recent studies have found that many factors may alter the gut microbiota, with the effects of diet being commonly-studied. Extrinsic stressors, including environmental stressors, antibiotic exposure, sleep disturbance, physical activity, and psychological stress, may also play important roles in altering the composition of the gut microbiota. Herein, we discuss the roles of the gut microbiota in intestinal inflammation in relation to diet and other extrinsic stressors.

Inflammatory and immunometabolic consequences of gut dysfunction in HIV: Parallels with IBD and implications for reservoir persistence and non-AIDS comorbidities

The gastrointestinal mucosa is critical for maintaining the integrity and functions of the gut. Disruption of this barrier is a hallmark and a risk factor for many intestinal and chronic inflammatory diseases. Inflammatory bowel disease (IBD) and HIV infection are characterized by microbial translocation and systemic inflammation. Despite the clinical overlaps between HIV and IBD, significant differences exist such as the severity of gut damage and mechanisms of immune cell homeostasis. Studies have supported the role of metabolic activation of immune cells in promoting chronic inflammation in HIV and IBD. This inflammatory response persists in HIV+ persons even after long-term virologic suppression by antiretroviral therapy (ART). Here, we review gut dysfunction and microbiota changes during HIV infection and IBD, and discuss how this may induce metabolic reprogramming of monocytes, macrophages and T cells to impact disease outcomes. Drawing from parallels with IBD, we highlight how factors such as lipopolysaccharides, residual viral replication, and extracellular vesicles activate biochemical pathways that regulate immunometabolic processes essential for HIV persistence and non-AIDS metabolic comorbidities. This review highlights new mechanisms and support for the use of immunometabolic-based therapeutics towards HIV remission/cure, and treatment of metabolic diseases.

Endometriosis Pathoetiology and Pathophysiology: Roles of Vitamin A, Estrogen, Immunity, Adipocytes, Gut Microbiome and Melatonergic Pathway on Mitochondria Regulation

Endometriosis is a common, often painful, condition that has significant implications for a woman’s fertility. Classically, endometriosis has been conceptualized as a local estrogen-mediated uterine condition driven by retrograde menstruation. However, recent work suggests that endometriosis may be a systemic condition modulated, if not driven, by prenatal processes. Although a diverse array of factors have been associated with endometriosis pathophysiology, recent data indicate that the low body mass index and decreased adipogenesis may be indicative of an early developmental etiology with alterations in metabolic function crucial to endometriosis pathoetiology.

The present article reviews the data on the pathoetiology and pathophysiology of endometriosis, suggesting key roles for alterations in mitochondria functioning across a number of cell types and body systems, including the immune system and gut microbiome. These changes are importantly regulated by decreases in vitamin A and its retinoic acid metabolites as well as increases in mitochondria estrogen receptor-beta and the N-acetylserotonin/melatonin ratio across development. This has treatment and future research implications for this still poorly managed condition, as well as for the association of endometriosis with a number of cancers.

Inflammatory Bowel Disease: A Stressed "Gut/Feeling"

Inflammatory bowel disease (IBD) is a chronic and relapsing intestinal inflammatory condition, hallmarked by a disturbance in the bidirectional interaction between gut and brain. In general, the gut/brain axis involves direct and/or indirect communication via the central and enteric nervous system, host innate immune system, and particularly the gut microbiota. This complex interaction implies that IBD is a complex multifactorial disease. There is increasing evidence that stress adversely affects the gut/microbiota/brain axis by altering intestinal mucosa permeability and cytokine secretion, thereby influencing the relapse risk and disease severity of IBD. Given the recurrent nature, therapeutic strategies particularly aim at achieving and maintaining remission of the disease. Alternatively, these strategies focus on preventing permanent bowel damage and concomitant long-term complications. In this review, we discuss the gut/microbiota/brain interplay with respect to chronic inflammation of the gastrointestinal tract and particularly shed light on the role of stress. Hence, we evaluated the therapeutic impact of stress management in IBD.

Cecal Infusion of Sodium Propionate Promotes Intestinal Development and Jejunal Barrier Function in Growing Pigs

Simple Summary

Microbial-derived short-chain fatty acids can exert influence on intestinal development and intestinal barrier function. Usually, it is well known that short-chain fatty acid butyrate provides energy for the colonic cell turnover and maintains the integrity of the colonic epithelium. However, the effect of short-chain fatty acid propionate on intestinal development and jejunal barrier function is given less attention. In this study, we found that cecal infusion of propionate promoted development of the jejunum and colon, and selectively enhanced jejunal tight junction protein expression. These results suggest that propionate by microbial fermentation in the hindgut has an important role in intestinal development and gut health.

Abstract

Short-chain fatty acids (SCFAs) produced by microbial fermentation facilitate the differentiation and proliferation of intestinal epithelium. However, the role of individual SCFAs, such as propionate, on intestinal development is still unclear. In the present study, sixteen barrows fitted with a cecal fistula were randomly divided into two groups for cecal infusion of either saline (control group) or sodium propionate (propionate group). After 28 days, the length and the relative weight of intestinal segments were calculated, the intestinal morphology was assessed, and the expression of tight junction protein was measured using qPCR and Western blotting. Compared to the saline group, the length of the colon was significantly increased in the propionate group (p < 0.05). The jejunal villi length and villi/crypt ratio in the propionate group were significantly higher than in the saline group (p < 0.05). Furthermore, propionate infusion significantly upregulated the mRNA levels of Claudin-4 and the expression of Claudin-1, Claudin-4, and Occludin protein in the jejunal mucosa (p < 0.05). Collectively, these findings revealed that the short-chain fatty acid propionate in the hindgut contributed to intestinal development, and selectively enhanced jejunal tight junction protein expression.

A holistic view of gallic acid-induced attenuation in colitis based on microbiome-metabolomics analysis

GA enema can treat UC by influencing microbiota-mediated metabolism.