Butyrate-induced transcriptional changes in human colonic mucosa

Oxidative Stress-Responsive Apoptosis Inducing Protein (ORAIP) Plays a Critical Role in Dextran Sulfate Sodium-Induced Murine Model of Ulcerative Colitis

Oxidative stress is implicated in the pathogenesis of various acute disorders including ischemia/reperfusion injury, ultraviolet/radiation burn, as well as chronic disorders such as dyslipidemia, atherosclerosis, diabetes mellitus, chronic renal disease, and inflammatory bowel disease (IBD). However, the precise mechanism involved remains to be clarified. We formerly identified a novel apoptosis-inducing humoral protein, in a hypoxia/reoxygenation-conditioned medium of cardiac myocytes, which proved to be 69th tyrosine-sulfated eukaryotic translation initiation factor 5A (eIF5A). We named this novel tyrosine-sulfated secreted form of eIF5A Oxidative Stress-Responsive Apoptosis-Inducing Protein (ORAIP). To investigate the role of ORAIP in a dextran sulfate sodium (DSS)-induced murine model of ulcerative colitis (UC), we analyzed the effects of in vivo treatment with anti-ORAIP neutralizing monoclonal antibody (mAb) on the DSS-induced disease exacerbation. The body weight in anti-ORAIP mAb-treated group was significantly heavier than that in a mouse IgG-treated control group on day 8 of DSS-treatment ((85.21 ± 1.03%) vs. (77.38 ± 2.07%); (mean ± SE0, n = 5 each, p < 0.01, t-test). In vivo anti-ORAIP mAb-treatment also significantly suppressed the shortening of colon length as well as Disease Activity Index (DAI) score ((5.00 ± 0.44) vs. (8.20 ± 0.37); (mean ± SE), n = 5 each, p < 0.001, t-test) by suppressing inflammation of the rectal tissue and apoptosis of intestinal mucosal cells. These data reveal the pivotal role of ORAIP in DSS-induced oxidative stress involved in an animal model of UC.

Cold exposure, gut microbiota and health implications: A narrative review

Temperature has been recognized as an important environmental factor affecting the composition and function of gut microbiota (GM). Although research on high-temperature impacts has been well studied, knowledge about the effect of cold exposure on GM remains limited. This narrative review aims to synthesize the latest scientific findings on the impact of cold exposure on mammalian GM, and its potential health implications. Chronic cold exposure could disrupt the α-diversity and the composition of GM in both experimental animals and wild-living hosts. Meanwhile, cold exposure could impact gut microbial metabolites, such as short-chain fatty acids. We also discussed plausible biological pathways and mechanisms by which cold-induced changes may impact host health, including metabolic homeostasis, fitness and thermogenesis, through the microbiota-gut-brain axis. Intriguingly, alterations in GM may provide a tool for favorably modulating the host response to the cold temperature. Finally, current challenges and future perspectives are discussed, emphasizing the need for translational research in humans. GM could be manipulated by utilizing nutritional strategies, such as probiotics and prebiotics, to deal with cold-related health issues and enhance well-being in populations living or working in cold environments.

Dietary nobiletin regulated cefuroxime- and levofloxacin-associated "gut microbiota-metabolism" imbalance and intestinal barrier dysfunction in mice

Nobiletin (NOB) exhibits significant biological activities and may be a potential dietary treatment for antibiotic-associated gut dysbiosis. In this study, mice were gavaged with 0.2 mL day-1 of 12.5 g L-1 cefuroxime (LFX) and 10 g L-1 levofloxacin (LVX) for a duration of 10 days, accompanied by 0.05% NOB to investigate the regulatory effect and potential mechanisms of NOB on antibiotic-induced intestinal microbiota disorder and intestinal barrier dysfunction. Our results indicated that dietary NOB improved the pathology of intestinal epithelial cells and the intestinal permeability by upregulating the expression of intestinal tight junction proteins (TJs) and the number of goblet cells. Furthermore, dietary NOB reduced the levels of serum lipopolysaccharide (LPS) and pro-inflammatory factors (TNF-α and IL-1β), thereby facilitating the restoration of the intestinal mucosal barrier. Additionally, dietary NOB increased the abundance of beneficial bacteria f_Lachnospiraceae and regulated the metabolic disorders of short-chain fatty acids (SCFAs) and bile acids (BAs). Notably, NOB supplementation resulted in elevated levels of butyric acid and lithocholic acid (LCA), which contributed to the repair of the intestinal mucosal barrier function and the maintenance of intestinal homeostasis. Collectively, our results propose a healthy dietary strategy for the prevention or mitigation of antibiotic-associated gut dysbiosis by dietary NOB.

Effects of sodium butyrate on growth performance, antioxidant status, inflammatory response and resistance to hypoxic stress in juvenile largemouth bass (Micropterus salmoides)

The aim of this study was to investigate the effects of sodium butyrate (SB) supplementation on growth performance, antioxidant enzyme activities, inflammatory factors, and hypoxic stress in largemouth bass (Micropterus salmoides). Diets were supplemented with different doses of SB at 0 (SB0), 0.5 (SB1), 1.0 (SB2) and 2.0 (SB3) g/kg. The hypoxic stress experiment was performed after 56 days of culture. The results showed that compared with the SB0 group, the final body weight, weight gain rate and protein deposition rate of the SB3 group were significantly increased (P<0.05), while FCR was significantly decreased (P<0.05). The contents of dry matter, crude lipids, and ash in the SB2 group were significantly higher than those in the SB0 group (P<0.05). The urea level was significantly decreased (P<0.05), and the glucose content was significantly increased (P<0.05) in the SB supplement group. Compared with the SB0 group, the SB2 group had significant reductions in the levels of serum triglyceride, cholesterol, elevated-density lipoprotein cholesterol, and low-density lipoprotein (P<0.05), and significant reductions in the levels of liver alkaline phosphatase and malondialdehyde (P<0.05). The total antioxidant capacity of the SB1 group was higher than that of other groups (P<0.05). Compared with the SB0 group, the mRNA expression of TLR22, MyD88, TGF-β1, IL-1β and IL-8 in the SB2 group significantly decreased (P<0.05). The cumulative mortality rate was significantly decreased in the SB2 and SB3 groups in comparison with that in the SB0 group after three hours of hypoxic stress (P<0.05). In a 56-day feeding trial, SB enhanced largemouth bass growth by increasing antioxidant enzyme activity and inhibiting TLR22-MyD88 signaling, therefore increasing cumulative mortality from hypoxic stress in largemouth bass.

The role of NADPH oxidase 1 in alcohol-induced oxidative stress injury of intestinal epithelial cells

Alcohol-mediated reactive oxygen species (ROS) play a vital role in intestinal barrier injury. However, the mechanism of ROS accumulation in enterocytes needs to be explored further. In our study, we found that chronic-binge ethanol-fed mice had increased levels of gut oxidative stress and high intestinal permeability. The transcription profiles of the colonic epithelial cells showed that the level of NADPH oxidase 1 (NOX1) was significantly elevated in alcohol-exposed mice compared with isocaloric-exposed mice. In vitro, NOX1 silencing alleviated ROS accumulation and the apoptosis of human colonic epithelial cells (NCM460), while NOX1 overexpression accelerated oxidative stress injury of NCM460 cells. Propionic acid was reduced in the gut of chronic-binge ethanol-fed mice, compared with isocaloric-fed mice, as observed through untargeted metabolomic analysis. Supplementation with propionate relieved ethanol-induced liver and intestinal barrier injuries and reduced the level of ROS accumulation and apoptosis of ethanol-induced colonic epithelial cells. Propionate alleviating NOX1 induced ROS injury of colonic epithelial cells, independent of G protein-coupled receptors. Propionate significantly inhibited histone deacetylase 2 (HDAC2) expressions both in ethanol-exposed colonic epithelial cells and TNF-α-treated NCM460. Chromatin immunoprecipitation (ChIP) assays showed that propionate suppressed the NOX1 expression by regulating histone acetylation in the gene promoter region. In conclusion, NOX1 induces oxidative stress injury of colonic epithelial cells in alcohol-related liver disease. Propionate, which can act as an endogenous HDAC2 inhibitor, can decrease levels of apoptosis of intestinal epithelial cells caused by oxidative stress.

Gut barrier-microbiota imbalances in early life lead to higher sensitivity to inflammation in a murine model of C-section delivery

BACKGROUND

Most interactions between the host and its microbiota occur at the gut barrier, and primary colonizers are essential in the gut barrier maturation in the early life. The mother-offspring transmission of microorganisms is the most important factor influencing microbial colonization in mammals, and C-section delivery (CSD) is an important disruptive factor of this transfer. Recently, the deregulation of symbiotic host-microbe interactions in early life has been shown to alter the maturation of the immune system, predisposing the host to gut barrier dysfunction and inflammation. The main goal of this study is to decipher the role of the early-life gut microbiota-barrier alterations and its links with later-life risks of intestinal inflammation in a murine model of CSD.

RESULTS

The higher sensitivity to chemically induced inflammation in CSD mice is related to excessive exposure to a too diverse microbiota too early in life. This early microbial stimulus has short-term consequences on the host homeostasis. It switches the pup's immune response to an inflammatory context and alters the epithelium structure and the mucus-producing cells, disrupting gut homeostasis. This presence of a too diverse microbiota in the very early life involves a disproportionate short-chain fatty acids ratio and an excessive antigen exposure across the vulnerable gut barrier in the first days of life, before the gut closure. Besides, as shown by microbiota transfer experiments, the microbiota is causal in the high sensitivity of CSD mice to chemical-induced colitis and in most of the phenotypical parameters found altered in early life. Finally, supplementation with lactobacilli, the main bacterial group impacted by CSD in mice, reverts the higher sensitivity to inflammation in ex-germ-free mice colonized by CSD pups' microbiota.

CONCLUSIONS

Early-life gut microbiota-host crosstalk alterations related to CSD could be the linchpin behind the phenotypic effects that lead to increased susceptibility to an induced inflammation later in life in mice. Video Abstract.

Transcriptome analysis in acute gastrointestinal graft-versus host disease reveals a unique signature in children and shared biology with pediatric inflammatory bowel disease

We performed transcriptomic analyses on freshly frozen (n=21) and paraffin-embedded (n=35) gastrointestinal (GI) biopsies from children with and without acute acute GI graft-versus-host disease (GvHD) to study differential gene expressions. We identified 164 significant genes, 141 upregulated and 23 downregulated, in acute GvHD from freshy frozen biopsies. CHI3L1 was the top differentially expressed gene in acute GvHD, involved in macrophage recruitment and bacterial adhesion. Mitochondrial genes were among the top downregulated genes. Immune deconvolution identified a macrophage cellular signature. Weighted gene co-expression network analysis showed enrichment of genes in the ERK1/2 cascade. Transcriptome data from 206 ulcerative colitis (UC) patients were included to uncover genes and pathways shared between GvHD and UC. Comparison with the UC transcriptome showed both shared and distinct pathways. Both UC and GvHD transcriptomes shared an innate antimicrobial signature and FCγ1RA/CD64 was upregulated in both acute GvHD (log-fold increase 1.7, P=0.001) and UC. Upregulation of the ERK1/2 cascade pathway was specific to GvHD. We performed additional experiments to confirm transcriptomics. Firstly, we examined phosphorylation of ERK (pERK) by immunohistochemistry on GI biopsies (acute GvHD n=10, no GvHD n=10). pERK staining was increased in acute GvHD biopsies compared to biopsies without acute GvHD (P=0.001). Secondly, plasma CD64, measured by enzyme-linked immunsorbant assay (n=85) was elevated in acute GI GvHD (P<0.001) compared with those without and was elevated in GVHD compared with inflammatory bowel disease (n=47) (P<0.001), confirming the upregulated expression seen in the transcriptome.

Interaction between Butyrate and Tumor Necrosis Factor α in Primary Rat Colonocytes

Butyrate, a short-chain fatty acid, is utilized by the gut epithelium as energy and it improves the gut epithelial barrier. More recently, it has been associated with beneficial effects on immune and cardiovascular homeostasis. Conversely, tumor necrosis factor alpha (TNFα) is a pro-inflammatory and pro-hypertensive cytokine. While butyrate and TNFα are both linked with hypertension, studies have not yet addressed their interaction in the colon. Here, we investigated the capacity of butyrate to modulate a host of effects of TNFα in primary rodent colonic cells in vitro. We measured ATP levels, cell viability, mitochondrial membrane potential (MMP), reactive oxygen species (ROS), mitochondrial oxidative phosphorylation, and glycolytic activity in colonocytes following exposure to either butyrate or TNFα, or both. To address the potential mechanisms, transcripts related to oxidative stress, cell fate, and cell metabolism (Pdk1, Pdk2, Pdk4, Spr, Slc16a1, Slc16a3, Ppargc1a, Cs, Lgr5, Casp3, Tnfr2, Bax, Bcl2, Sod1, Sod2, and Cat) were measured, and untargeted liquid chromatography-tandem mass spectrometry (LC-MS/MS) was employed to profile the metabolic responses of colonocytes following exposure to butyrate and TNFα. We found that both butyrate and TNFα lowered cellular ATP levels towards a quiescent cell energy phenotype, characterized by decreased oxygen consumption and extracellular acidification. Co-treatment with butyrate ameliorated TNFα-induced cytotoxicity and the reduction in cell viability. Butyrate also opposed the TNFα-mediated decrease in MMP and mitochondrial-to-intracellular calcium ratios, suggesting that butyrate may protect colonocytes against TNFα-induced cytotoxicity by decreasing mitochondrial calcium flux. The relative expression levels of pyruvate dehydrogenase kinase 4 (Pdk4) were increased via co-treatment of butyrate and TNFα, suggesting the synergistic inhibition of glycolysis. TNFα alone reduced the expression of monocarboxylate transporters slc16a1 and slc16a3, suggesting effects of TNFα on butyrate uptake into colonocytes. Of the 185 metabolites that were detected with LC-MS, the TNFα-induced increase in biopterin produced the only significant change, suggesting an alteration in mitochondrial biogenesis in colonocytes. Considering the reports of elevated colonic TNFα and reduced butyrate metabolism in many conditions, including in hypertension, the present work sheds light on cellular interactions between TNFα and butyrate in colonocytes that may be important in understanding conditions of the colon.

Fecal Microbiota Transplantation and Other Gut Microbiota Manipulation Strategies

The gut microbiota is composed of bacteria, archaea, phages, and protozoa. It is now well known that their mutual interactions and metabolism influence host organism pathophysiology. Over the years, there has been growing interest in the composition of the gut microbiota and intervention strategies in order to modulate it. Characterizing the gut microbial populations represents the first step to clarifying the impact on the health/illness equilibrium, and then developing potential tools suited for each clinical disorder. In this review, we discuss the current gut microbiota manipulation strategies available and their clinical applications in personalized medicine. Among them, FMT represents the most widely explored therapeutic tools as recent guidelines and standardization protocols, not only for intestinal disorders. On the other hand, the use of prebiotics and probiotics has evidence of encouraging findings on their safety, patient compliance, and inter-individual effectiveness. In recent years, avant-garde approaches have emerged, including engineered bacterial strains, phage therapy, and genome editing (CRISPR-Cas9), which require further investigation through clinical trials.

A Chinese herbs complex ameliorates gut microbiota dysbiosis induced by intermittent cold exposure in female rats

Cold is a common source of stress in the alpine areas of northern China. It affects the microbial community, resulting in the invasion of pathogenic microorganisms and intestinal diseases. In recent years, studies have reported that Chinese herbal extracts and their fermentation broth have a significant beneficial effect on gut microbiota. This study aimed to investigate the probiotic effect of a self-designed Chinese herbs complex on the gut microbiota of rats exposed to cold. The rats were treated with intermittent cold exposure and Chinese herbs complex for 14 days, and the gut microbiota composition and other parameters were assayed. The 16s ribosomal DNA high-throughput sequencing and analysis confirmed that the Chinese herbs complex positively improved the gut microbiota. We found that cold exposure could lead to significant changes in the composition of gut microbiota, and affect the intestinal barrier and other physiological functions. The relative abundance of some probiotics in the genus such as Roseburia, Parasutterella, and Elusimicrobium in rats treated with Chinese herbs complex was significantly increased. Serum D-lactic acid (D-LA) and lipopolysaccharide (LPS) were increased in the cold exposure group and decreased in the Chinese herbs complex-treated group. Moreover, the Chinese herbs complex significantly increased the protein expression of occludin. In conclusion, the Chinese herbs complex is effective in restoring the gut microbiota caused by cold exposure, improving the function of the intestinal barrier, and may act as a prebiotic in combatting gut dysbiosis.

Butyrate to combat obesity and obesity-associated metabolic disorders: Current status and future implications for therapeutic use

Evidence is increasing that disturbances in the gut microbiome may play a significant role in the etiology of obesity and type 2 diabetes. The short chain fatty acid butyrate, a major end product of the bacterial fermentation of indigestible carbohydrates, is reputed to have anti-inflammatory properties and positive effects on body weight control and insulin sensitivity. However, whether butyrate has therapeutic potential for the treatment and prevention of obesity and obesity-related complications remains to be elucidated. Overall, animal studies strongly indicate that butyrate administered via various routes (e.g., orally) positively affects adipose tissue metabolism and functioning, energy and substrate metabolism, systemic and tissue-specific inflammation, and insulin sensitivity and body weight control. A limited number of human studies demonstrated interindividual differences in clinical effectiveness suggesting that outcomes may depend on the metabolic, microbial, and lifestyle-related characteristics of the target population. Hence, despite abundant evidence from animal data, support of human data is urgently required for the implementation of evidence-based oral and gut-derived butyrate interventions. To increase the efficacy of butyrate-focused interventions, future research should investigate which factors impact treatment outcomes including baseline gut microbial activity and functionality, thereby optimizing targeted-interventions and identifying individuals that merit most from such interventions.

Opportunities and challenges for synthetic biology in the therapy of inflammatory bowel disease

Inflammatory bowel disease (IBD) is a complex, chronic intestinal inflammatory disorder that primarily includes Crohn’s disease (CD) and ulcerative colitis (UC). Although traditional antibiotics and immunosuppressants are known as the most effective and commonly used treatments, some limitations may be expected, such as limited efficacy in a small number of patients and gut flora disruption. A great many research studies have been done with respect to the etiology of IBD, while the composition of the gut microbiota is suggested as one of the most influential factors. Along with the development of synthetic biology and the continuing clarification of IBD etiology, broader prospects for novel approaches to IBD therapy could be obtained. This study presents an overview of the currently existing treatment options and possible therapeutic targets at the preclinical stage with respect to microbial synthesis technology in biological therapy. This study is highly correlated to the following topics: microbiota-derived metabolites, microRNAs, cell therapy, calreticulin, live biotherapeutic products (LBP), fecal microbiota transplantation (FMT), bacteriophages, engineered bacteria, and their functional secreted synthetic products for IBD medical implementation. Considering microorganisms as the main therapeutic component, as a result, the related clinical trial stability, effectiveness, and safety analysis may be the major challenges for upcoming research. This article strives to provide pharmaceutical researchers and developers with the most up-to-date information for adjuvant medicinal therapies based on synthetic biology.

The Untapped Potential of Ginsenosides and American Ginseng Berry in Promoting Mental Health via the Gut-Brain Axis

Despite the popularity of the ginseng (Panax) root in health research and on the market, the ginseng berry’s potential remains relatively unexplored. Implementing ginseng berry cultivations and designing berry-derived products could improve the accessibility to mental health-promoting nutraceuticals. Indeed, the berry could have a higher concentration of neuroprotective and antidepressant compounds than the root, which has already been the subject of research demonstrating its efficacy in the context of neuroprotection and mental health. In this review, data on the berry’s application in supporting mental health via the gut–brain axis is compiled and discussed.

Mucolytic bacteria: prevalence in various pathological diseases

All mucins are highly glycosylated and a key constituent of the mucus layer that is vigilant against pathogens in many organ systems of animals and humans. The viscous layer is organized in bilayers, i.e., an outer layer that is loosely arranged, variable in thickness, home to the commensal microbiota that grows in the complex environment, and an innermost layer that is stratified, non-aspirated, firmly adherent to the epithelial cells and devoid of any microorganisms. The O-glycosylation moiety represents the site of adhesion for pathogens and due to the increase of motility, mucolytic activity, and upregulation of virulence factors, some microorganisms can circumvent the component of the mucus layer and cause disruption in organ homeostasis. A dysbiotic microbiome, defective mucus barrier, and altered immune response often result in various diseases. In this review, paramount emphasis is given to the role played by the bacterial species directly or indirectly involved in mucin degradation, alteration in mucus secretion or its composition or mucin gene expression, which instigates many diseases in the digestive, respiratory, and other organ systems. A systematic view can help better understand the etiology of some complex disorders such as cystic fibrosis, ulcerative colitis and expand our knowledge about mucin degraders to develop new therapeutic approaches to correct ill effects caused by these mucin-dwelling pathogens.

Dietary Fibre Modulates the Gut Microbiota

Dietary fibre has long been established as a nutritionally important, health-promoting food ingredient. Modern dietary practices have seen a significant reduction in fibre consumption compared with ancestral habits. This is related to the emergence of low-fibre “Western diets” associated with industrialised nations, and is linked to an increased prevalence of gut diseases such as inflammatory bowel disease, obesity, type II diabetes mellitus and metabolic syndrome. The characteristic metabolic parameters of these individuals include insulin resistance, high fasting and postprandial glucose, as well as high plasma cholesterol, low-density lipoprotein (LDL) and high-density lipoprotein (HDL). Gut microbial signatures are also altered significantly in these cohorts, suggesting a causative link between diet, microbes and disease. Dietary fibre consumption has been hypothesised to reverse these changes through microbial fermentation and the subsequent production of short-chain fatty acids (SCFA), which improves glucose and lipid parameters in individuals who harbour diseases associated with dysfunctional metabolism. This review article examines how different types of dietary fibre can differentially alter glucose and lipid metabolism through changes in gut microbiota composition and function.

Quercetin improves gut dysbiosis in antibiotic-treated mice

The diversity and activity of the gut microbiota residing in humans and animals are significantly influenced by the diet. Quercetin, one of the representative polyphenols in human diets, possesses a wide range of biological properties. The aim of this study was to investigate the prebiotic effects of quercetin in antibiotic-treated mice. Gut dysbiosis was successfully induced in mice by treatment with an antibiotic cocktail. Gas chromatography and 16S rDNA high-throughput sequencing techniques were used to investigate short-chain fatty acid content and gut microbial diversity and composition. The results showed that quercetin supplementation significantly improved the diversity of the gut bacterial community in antibiotic-treated mice (P < 0.05). Meanwhile, intestinal barrier function was also recovered remarkably as indicated by a decrease in the content of serum d-lactic acid and the activity of serum diamine oxidase (P < 0.05). The length of intestinal villi and mucosal thickness were also significantly increased in response to quercetin treatment (P < 0.05). Furthermore, the production of butyrate in faeces was enhanced significantly in quercetin-treated mice (P < 0.05). In conclusion, quercetin is effective in recovering gut microbiota in mice after antibiotic treatment and may act as a prebiotic in combatting gut dysbiosis.

Environmental noise stress disturbs commensal microbiota homeostasis and induces oxi-inflammmation and AD-like neuropathology through epithelial barrier disruption in the EOAD mouse model

Background

Both genetic factors and environmental hazards, including environmental noise stress, have been associated with gut microbiome that exacerbates Alzheimer’s disease (AD) pathology. However, the role and mechanism of environmental risk factors in early-onset AD (EOAD) pathogenesis remain unclear.

Methods

The molecular pathways underlying EOAD pathophysiology following environmental noise exposure were evaluated using C57BL/6 wild-type (WT) and APP/PS1 Tg mouse models. The composition differences in intestinal microbiota were analyzed by 16S rRNA sequencing and Tax4Fun to predict the metagenome content from sequencing results. An assessment of the flora dysbiosis-triggered dyshomeostasis of oxi-inflamm-barrier and the effects of the CNS end of the gut–brain axis was conducted to explore the underlying pathological mechanisms.

Results

Both WT and APP/PS1 mice showed a statistically significant relationship between environmental noise and the taxonomic composition of the corresponding gut microbiome. Bacterial-encoded functional categories in noise-exposed WT and APP/PS1 mice included phospholipid and galactose metabolism, oxidative stress, and cell senescence. These alterations corresponded with imbalanced intestinal oxidation and anti-oxidation systems and low-grade systemic inflammation following noise exposure. Mechanistically, axis-series experiments demonstrated that following noise exposure, intestinal and hippocampal tight junction protein levels reduced, whereas serum levels of inflammatory mediator were elevated. Regarding APP/PS1 overexpression, noise-induced abnormalities in the gut–brain axis may contribute to aggravation of neuropathology in the presymptomatic stage of EOAD mice model.

Conclusion

Our results demonstrate that noise exposure has deleterious effects on the homeostasis of oxi-inflamm-barrier in the microbiome–gut–brain axis. Therefore, at least in a genetic context, chronic noise may aggravate the progression of EOAD.

The Role of Mucosal Immunity and Recombinant Probiotics in SARS-CoV2 Vaccine Development

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV2), causing the 2019 novel coronavirus disease (COVID-19), was introduced by WHO (World Health Organization) as "pandemic" in March 2020. According to WHO, thus far (23 November 2020) 58,425,681 infected cases including 1,385,218 deaths have been reported worldwide. In order to reduce transmission and spread of this lethal virus, attempts are globally being made to develop an appropriate vaccine. Intending to neutralize pathogens at their initial entrance site, protective mucosal immunity is inevitably required. In SARS-CoV2 infection and transmission, respiratory mucosa plays a key role; hence, apparently mucosal vaccination could be a superior approach to elicit mucosal and systemic immune responses simultaneously. In this review, the advantages of mucosal vaccination to control COVID-19 infection, limitations, and outcomes of mucosal vaccines have been highlighted. Considering the gut microbiota dysregulation in COVID-19, we further provide evidences on utilization of recombinant probiotics, particularly lactic acid bacteria (LAB) as vaccine carrier. Their intrinsic immunomodulatory features, natural adjuvanticity, and feasible expression of relevant antigen in the mucosal surface make them more appealing as live cell factory. Among all available platforms, bioengineered probiotics are considered as the most affordable, most practical, and safest vaccination approach to halt this emerging virus.

The Effect of Sodium Butyrate Enemas Compared with Placebo on Disease Activity, Endoscopic Scores, and Histological and Inflammatory Parameters in Inflammatory Bowel Diseases: A Systematic Review of Randomised Controlled Trials

INTRODUCTION

Administration of butyrate enemas might improve the health status of patients with inflammatory bowel disease (IBD). However, the results seem equivocal. Therefore, this systematic review aimed to assess the effect of sodium butyrate enemas on disease activity index (DAI), endoscopic scores, as well as histological and inflammatory parameters in IBD patients.

METHODS

The PubMed, Scopus, Web of Science, and Cochrane databases were searched. Randomised controlled trials published in English that assessed the effect of butyrate enemas on DAI, clinical symptoms, inflammatory markers, as well as histological and endoscopic scores in patients with Crohn's disease (CD) and ulcerative colitis (UC) were included in the analysis.

RESULTS

Eight studies involving 227 UC patients were included in this analysis. Only one study reported significant differences in DAI between groups. Besides, butyrate treatment groups did not differ significantly from controls concerning the effect on endoscopic and histological scores. Moreover, butyrate enemas exerted a significant effect on few inflammatory parameters measured in colonic mucosal biopsies.

CONCLUSION

The current evidence is limited and does not support the application of butyrate enemas in UC. There are no reliable data regarding the efficacy of butyrate enemas in CD. The systematic review protocol was registered in the PROSPERO database (CRD42020163654).

Characterisation of gut microbiota of obesity and type 2 diabetes in a rodent model

Various studies have suggested that the gut microbiome interacts with the host and may have a significant role in the aetiology of obesity and Type 2 Diabetes (T2D). It was hypothesised that bacterial communities in obesity and T2D differ from control and compromise normal interactions between host and microbiota. Obesity and T2D were developed in rats by feeding a high-fat diet or a high-fat diet plus a single low-dose streptozotocin administration, respectively. The microbiome profiles and their metabolic potentials were established by metagenomic 16S rRNA sequencing and bioinformatics. Taxonomy and predicted metabolism-related genes in obesity and T2D were markedly different from controls and indeed from each other. Diversity was reduced in T2D but not in Obese rats. Factors likely to compromise host intestinal, barrier integrity were found in Obese and T2D rats including predicted, decreased bacterial butyrate production. Capacity to increase energy extraction via ABC-transporters and carbohydrate metabolism were enhanced in Obese and T2D rats. T2D was characterized by increased proinflammatory molecules. While obesity and T2D show distinct differences, results suggest that in both conditions Bacteroides and Blautia species were increased indicating a possible mechanistic link.

Organoids to Study Intestinal Nutrient Transport, Drug Uptake and Metabolism - Update to the Human Model and Expansion of Applications

Intestinal transport and sensing processes and their interconnection to metabolism are relevant to pathologies such as malabsorption syndromes, inflammatory diseases, obesity and type 2 diabetes. Constituting a highly selective barrier, intestinal epithelial cells absorb, metabolize, and release nutrients into the circulation, hence serving as gatekeeper of nutrient availability and metabolic health for the whole organism. Next to nutrient transport and sensing functions, intestinal transporters including peptide transporter 1 (PEPT1) are involved in the absorption of drugs and prodrugs, including certain inhibitors of angiotensin-converting enzyme, protease inhibitors, antivirals, and peptidomimetics like β-lactam antibiotics. Here, we verify the applicability of 3D organoids for in vitro investigation of intestinal biochemical processes related to transport and metabolism of nutrients and drugs. Establishing a variety of methodologies including illustration of transporter-mediated nutrient and drug uptake and metabolomics approaches, we highlight intestinal organoids as robust and reliable tool in this field of research. Currently used in vitro models to study intestinal nutrient absorption, drug transport and enterocyte metabolism, such as Caco-2 cells or rodent explant models are of limited value due to their cancer and non-human origin, respectively. Particularly species differences result in poorly correlative data and findings obtained in these models cannot be extrapolated reliably to humans, as indicated by high failure rates in drug development pipelines. In contrast, human intestinal organoids represent a superior model of the intestinal epithelium and might help to implement the 3Rs (Reduction, Refinement and Replacement) principle in basic science as well as the preclinical and regulatory setup.

Gut Microbiota and Heart, Vascular Injury

The gut microbiota plays an important role in maintaining human health. Accumulating evidence has indicated an intimate relationship between gut microbiota and cardiovascular diseases (CVD) which has become the leading cause of death worldwide. The alteration of gut microbial composition (gut dysbiosis) has been proven to contribute to atherosclerosis, the basic pathological process of CVD. In addition, the metabolites of gut microbiota have been found to be closely related to the development of CVD. For example, short-chain fatty acids are widely acclaimed beneficial effect against CVD, whereas trimethylamine-N-oxide is considered as a contributing factor in the development of CVD. In this chapter, we mainly discuss the gut microbial metabolite-involved mechanisms of CVD focusing on atherosclerosis, hypertension, diabetes, obesity, and heart failure. Targeting gut microbiota and related metabolites are novel and promising strategies for the treatment of CVD.

Acute Effects of Butyrate on Induced Hyperpermeability and Tight Junction Protein Expression in Human Colonic Tissues

Intact intestinal barrier function is essential for maintaining intestinal homeostasis. A dysfunctional intestinal barrier can lead to local and systemic inflammation through translocation of luminal antigens and has been associated with a range of health disorders. Butyrate, a short-chain fatty acid derived from microbial fermentation of dietary fibers in the colon, has been described as an intestinal barrier-strengthening agent, although mainly by using in vitro and animal models. This study aimed to investigate butyrate’s ability to prevent intestinal hyperpermeability, induced by the mast cell degranulator Compound 48/80 (C48/80), in human colonic tissues. Colonic biopsies were collected from 16 healthy subjects and intestinal permeability was assessed by Ussing chamber experiments. Furthermore, the expression levels of tight junction-related proteins were determined by quantitative reverse transcription polymerase chain reaction (qRT-PCR). Pre-treatment with 5 mM butyrate or 25 mM butyrate did not protect the colonic tissue against induced paracellular or transcellular hyperpermeability, measured by FITC-dextran and horseradish peroxidase passage, respectively. Biopsies treated with 25 mM butyrate prior to stimulation with C48/80 showed a reduced expression of claudin 1. In conclusion, this translational ex vivo study did not demonstrate an acute protective effect of butyrate against a chemical insult to the intestinal barrier in healthy humans.

A story of liver and gut microbes: how does the intestinal flora affect liver disease? A review of the literature

Each individual is endowed with a unique gut microbiota (GM) footprint that mediates numerous host-related physiological functions, such as nutrient metabolism, maintenance of the structural integrity of the gut mucosal barrier, immunomodulation, and protection against microbial pathogens. Because of increased scientific interest in the GM, its central role in the pathophysiology of many intestinal and extraintestinal conditions has been recognized. Given the close relationship between the gastrointestinal tract and the liver, many pathological processes have been investigated in the light of a microbial-centered hypothesis of hepatic damage. In this review we introduce to neophytes the vast world of gut microbes, including prevalent bacterial distribution in healthy individuals, how the microbiota is commonly analyzed, and the current knowledge of the role of GM in liver disease pathophysiology. Also, we highlight the potentials and downsides of GM-based therapy.

Impact of oral probiotic Lactobacillus acidophilus vaccine strains on the immune response and gut microbiome of mice

The potential role of probiotic bacteria as adjuvants in vaccine trials led to their use as nonparenteral live mucosal vaccine vectors. Yet, interactions between these vectors, the host and the microbiome are poorly understood. This study evaluates impact of three probiotic, Lactobacillus acidophilus, vector strains, and their interactions with the host's immune response, on the gut microbiome. One strain expressed the membrane proximal external region from HIV-1 (MPER). The other two expressed MPER and either secreted interleukin-1ß (IL-1ß) or expressed the surface flagellin subunit C (FliC) as adjuvants. We also used MPER with rice bran as prebiotic supplement. We observed a strain dependent, differential effect suggesting that MPER and IL-1β induced a shift of the microbiome while FliC had minimal impact. Joint probiotic and prebiotic use resulted in a compound effect, highlighting a potential synbiotic approach to impact efficacy of vaccination. Careful consideration of constitutive adjuvants and use of prebiotics is needed depending on whether or not to target microbiome modulation to improve vaccine efficacy. No clear associations were observed between total or MPER-specific IgA and the microbiome suggesting a role for other immune mechanisms or a need to focus on IgA-bound, resident microbiota, most affected by an immune response.

Gut microbiota combined with metabolomics reveals the metabolic profile of the normal aging process and the anti-aging effect of FuFang Zhenshu TiaoZhi(FTZ) in mice

The aging process is accompanied by changes in the gut microbiota and metabolites. This study aimed to reveal the relationship between gut microbiota and the metabolome at different ages, as well as the anti-aging effect of FTZ, which is an effective clinical prescription for the treatment of hyperlipidemia and diabetes.

METHODS

In the present study, mice were randomly divided into different age and FTZ treatment groups. The aging-relevant behavioral phenotype the levels of blood glucose, cholesterol, triglycerides, low density lipoprotein cholesterol, free fatty acids, high density lipoprotein-cholesterol and cytokine TNF-α,IL-6, IL-8 in the serum were measured. Changes of serum metabolties were analyzed by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-Q-TOF/MS). Gut microbiota were identified using 16S rDNA sequencing.

RESULTS

Our results indicated that with age, the aging-relevant behavioral phenotype appeared, glucose and lipid metabolism disordered, secretion levels of cytokine TNF-α, IL-6 and IL-8 increased.The Firmicutes/Bacteroidetes ratio changed with age, first increasing and then decreasing, and the microbial diversity and the community richness of the aging mice were improved by FTZ. The abundance of opportunistic bacteria decreased (Lactobacillus murinus, Erysipelatoclostridium), while the levels of protective bacteria such as Butyricimonas, Clostridium and Akkermansia increased. Metabolic analysis identified 24 potential biomarkers and 10 key pathways involving arachidonic acid metabolism, phospholipid metabolism, fatty acid metabolism, taurine and hypotaurine metabolism. Correlation analysis between the gut microbiota and biomarkers suggested that the relative abundance of protective bacteria was negatively correlated with the levels of leukotriene E4, 20-HETE and arachidonic acid, which was different from protective bacteria.

CONCLUSION

Shifts of gut microbiota and metabolomic profiles were observed in the mice during the normal aging process, and treatment with FTZ moderately corrected the aging, which may be mediated via interference with arachidonic acid metabolism, sphingolipid metabolism, glycerophospholipid metabolism, taurine and hypotaurine metabolism and gut microbiota in mice.

Effects of Land Transport Stress on Variations in Ruminal Microbe Diversity and Immune Functions in Different Breeds of Cattle

Simple Summary

Anti-stress is an emergent research point to current cattle industry. Land transport stress, a negative off-site fattening mode, causing a serious problems to beef cattle production, such as nutrition-metabolism, hormone secretion levels, and immune competence are imbalanced. In this paper we compared among Simmental Crossbred Cattle (SC), Native Yellow Cattle (NY), and Cattle Yak (CY) about ruminal microbe diversity and immune functions before and after transportation. The results showing that transport stress leads to increase secretion of hormone, both pro-inflammatory cytokines and rumen lipopolysaccharide. Meanwhile, the ruminal microbiota OTUs, Chao1, and Shannon were also changed, and Prevotella1 in NY group was higher than other groups before transport; after transport Firmicutes and Lactobacillus were increased than other groups in CY. The rumen microbiota also related with serum cytokine. Under transport stress, rumen microbiota affect the secretion of hormone levels and immune functions and breed factors affect the performance of stress resistance.

Abstract

The intensity and specialization of beef cattle production make off-site fattening, and introduce new breeds need transportation to achieve the goals. The present study was aimed to investigate effects of land transport stress on hormones levels, microbial fermentation, microbial composition, immunity and correlation among them among Simmental Crossbred Cattle (SC), Native Yellow Cattle (NY), and Cattle Yak (CY). High-throughput sequencing was used to investigate the rumen microbial diversity. After transport stress cortisol (COR), adrenocorticotropic hormone (ACTH) and pro-inflammatory cytokines IL-6, TNF-α, and IL-1β were increased (p < 0.05) in all groups. Rumen lipopolysaccharide (LPS) was increased (p < 0.05) in SC and CY groups. Total volatile fatty acids were increased (p < 0.05) in all groups. The ruminal microbiota about OTUs, Chao1, and Shannon in SC and CY groups were higher than before transport. Prevotella1 in NY group was higher (p < 0.05) than other groups before transport; after transport Firmicutes and Lactobacillus were increased (p < 0.05) than other groups in CY. Lactobacillus was positively correlated with IL-6 and IL-4. Under transport stress, cattle may suffer from inflammatory response through modulating HPA axis and microbiota metabolite affects the secretion of hormone levels and immune function and breeds factor affect the performance of stress resistance.

Inflammation in gastrointestinal disorders: prevalent socioeconomic factors

Western populations harbor a chronic inflammation pattern that lacks organ cardinal signs (edema, increased temperature, pain, and impaired function), releases increased levels of C-reactive protein, and often runs a creeping clinical course with generalized debilitating disease superimposed on system-specific involvement, mostly including nervous tissue (multiple sclerosis, Parkinson’s syndromes), joints (arthritis), and skin (psoriasis). A finalistic interpretation may apply to the consideration of the gut as the source of inflammation. In fact, these kind of local events as well as the remote manifestations named above, could be conditioned by the microbiome, the huge cell population indwelling the gut which is under growing scrutiny. The role of the gut as a barrier organ justifies lingering submucosal inflammation as a patrolling activity to maintain bodily integrity; the microbiome, launching inflammogenic signals in response to abrupt diet changes, confers to gut inflammation a socioeconomic vector calling for hitherto unrecognized multi-disciplinary interventions.

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Maturation of White Adipose Tissue Function in C57BL/6j Mice From Weaning to Young Adulthood

White adipose tissue (WAT) distribution and WAT mitochondrial function contribute to total body metabolic health throughout life. Nutritional interventions starting in the postweaning period may impact later life WAT health and function. We therefore assessed changes in mitochondrial density and function markers in WAT depots of young mice. Inguinal (ING), epididymal (EPI) and retroperitoneal (RP) WAT of 21, 42 and 98 days old C57BL/6j mice was collected. Mitochondrial density [citrate synthase (CS), mtDNA] and function [subunits of oxidative phosphorylation complexes (OXPHOS)] markers were analyzed, together with gene expression of browning markers (Ucp1, Cidea). mRNA of ING WAT of 21 and 98 old mice was sequenced to further investigate functional changes of the mitochondria and alterations in cell populations. CS levels decreased significantly over time in all depots. ING showed most pronounced changes, including significantly decreased levels of OXPHOS complex I, II, and III subunits and gene expression of Ucp1 (PN21-42 and PN42-98) and Cidea (PN42-98). White adipocyte markers were higher at PN98 in ING WAT. Analyses of RNA sequence data showed that the mitochondrial functional profile changed over time from “growth-supporting” mitochondria focused on ATP production (and dissipation), to more steady-state mitochondria with more diverse functions and higher biosynthesis. Mitochondrial density and energy metabolism markers declined in all three depots over time after weaning. This was most pronounced in ING WAT and associated with reduced browning markers, increased whitening and an altered metabolism. In particular the PN21-42 period may provide a time window to study mitochondrial adaptation and effects of nutritional exposures relevant for later life metabolic health.

A PRDM16-Driven Metabolic Signal from Adipocytes Regulates Precursor Cell Fate

The precursor cells for metabolically beneficial beige adipocytes can alternatively become fibrogenic and contribute to adipose fibrosis. We found that cold exposure or β3-adrenergic agonist treatment of mice decreased the fibrogenic profile of precursor cells and stimulated beige adipocyte differentiation. This fibrogenic-to-adipogenic transition was impaired in aged animals, correlating with reduced adipocyte expression of the transcription factor PRDM16. Genetic loss of Prdm16 mimicked the effect of aging in promoting fibrosis, whereas increasing PRDM16 in aged mice decreased fibrosis and restored beige adipose development. PRDM16-expressing adipose cells secreted the metabolite β-hydroxybutyrate (BHB), which blocked precursor fibrogenesis and facilitated beige adipogenesis. BHB catabolism in precursor cells, mediated by BDH1, was required for beige fat differentiation in vivo. Finally, dietary BHB supplementation in aged animals reduced adipose fibrosis and promoted beige fat formation. Together, our results demonstrate that adipocytes secrete a metabolite signal that controls beige fat remodeling.

The role of the microbiome for human health: from basic science to clinical applications

The 2017 annual symposium organized by the University Medical Center Groningen in The Netherlands focused on the role of the gut microbiome in human health and disease. Experts from academia and industry examined interactions of prebiotics, probiotics, or vitamins with the gut microbiome in health and disease, the development of the microbiome in early-life and the role of the microbiome on the gut–brain axis. The gut microbiota changes dramatically during pregnancy and intrinsic factors (such as stress), in addition to extrinsic factors (such as diet, and drugs) influence the composition and activity of the gut microbiome throughout life. Microbial metabolites, e.g. short-chain fatty acids affect gut–brain signaling and the immune response. The gut microbiota has a regulatory role on anxiety, mood, cognition and pain which is exerted via the gut–brain axis. Ingestion of prebiotics or probiotics has been used to treat a range of conditions including constipation, allergic reactions and infections in infancy, and IBS. Fecal microbiota transplantation (FMT) highly effective for treating recurrent Clostridium difficile infections. The gut microbiome affects virtually all aspects of human health, but the degree of scientific evidence, the models and technologies and the understanding of mechanisms of action vary considerably from one benefit area to the other. For a clinical practice to be broadly accepted, the mode of action, the therapeutic window, and potential side effects need to thoroughly be investigated. This calls for further coordinated state-of-the art research to better understand and document the human gut microbiome’s effects on human health.

Growth performance, lipid metabolism, and health status of grass carp (Ctenopharyngodon idella) fed three different forms of sodium butyrate

Sodium butyrate (SB) can be coated with fatty acid matrix. In this study, the effects of three SB forms, being zero-lipid-coated (SB-A), half-lipid-coated (SB-B), and 2/3 lipid-coated (SB-C) (w/w), on growth, lipid metabolism, and health status of grass carp (Ctenopharyngodon idella) were investigated. The three forms of SB were added to a control diet to form three SB diets, Con., SB-A, SB-B, and SB-C, where the pure SB in each SB diet was kept at the same level (500 mg kg^-1). A total of 216 C. idella (14.10 ± 0.60 g/fish) were allotted into four groups (triplicate per group) and fed the four diets respectively for 56 days, and then fish were sampled and determined. Fish growth was not affected by any of the three forms of SB. Viscerosomatic index, intraperitoneal fat index, and crude lipid of hepatopancreas and muscle were significantly decreased and villus height of intestine and mRNA expression of MyD88 and TLR22 in hepatopancreas were significantly improved in SB diets compared with control (p < 0.05), respectively. MiSeq sequencing of the V3-V4 region of bacterial 16S rRNA gene revealed that SB increased the relative abundances of intestinal healthy bacteria, Fusobacteria and Bacteroides, and the abundances of Cetobacterium decreased in the SB-C group. In conclusion, the present results showed that three forms of SB, without affecting the growth of fish, respectively decreased lipid accumulation and probably have a beneficial effect on health of C. idella.

Metaproteomics reveals potential mechanisms by which dietary resistant starch supplementation attenuates chronic kidney disease progression in rats

BACKGROUND

Resistant starch is a prebiotic metabolized by the gut bacteria. It has been shown to attenuate chronic kidney disease (CKD) progression in rats. Previous studies employed taxonomic analysis using 16S rRNA sequencing and untargeted metabolomics profiling. Here we expand these studies by metaproteomics, gaining new insight into the host-microbiome interaction.

METHODS

Differences between cecum contents in CKD rats fed a diet containing resistant starch with those fed a diet containing digestible starch were examined by comparative metaproteomics analysis. Taxonomic information was obtained using unique protein sequences. Our methodology results in quantitative data covering both host and bacterial proteins.

RESULTS

5,834 proteins were quantified, with 947 proteins originating from the host organism. Taxonomic information derived from metaproteomics data surpassed previous 16S RNA analysis, and reached species resolutions for moderately abundant taxonomic groups. In particular, the Ruminococcaceae family becomes well resolved-with butyrate producers and amylolytic species such as R. bromii clearly visible and significantly higher while fibrolytic species such as R. flavefaciens are significantly lower with resistant starch feeding. The observed changes in protein patterns are consistent with fiber-associated improvement in CKD phenotype. Several known host CKD-associated proteins and biomarkers of impaired kidney function were significantly reduced with resistant starch supplementation. Data are available via ProteomeXchange with identifier PXD008845.

CONCLUSIONS

Metaproteomics analysis of cecum contents of CKD rats with and without resistant starch supplementation reveals changes within gut microbiota at unprecedented resolution, providing both functional and taxonomic information. Proteins and organisms differentially abundant with RS supplementation point toward a shift from mucin degraders to butyrate producers.

Roles of Probiotic Lactobacilli Inclusion in Helping Piglets Establish Healthy Intestinal Inter-environment for Pathogen Defense

The gastrointestinal tract of pigs is densely populated with microorganisms that closely interact with the host and with ingested feed. Gut microbiota benefits the host by providing nutrients from dietary substrates and modulating the development and function of the digestive and immune systems. An optimized gastrointestinal microbiome is crucial for pigs' health, and establishment of the microbiome in piglets is especially important for growth and disease resistance. However, the microbiome in the gastrointestinal tract of piglets is immature and easily influenced by the environment. Supplementing the microbiome of piglets with probiotic bacteria such as Lactobacillus could help create an optimized microbiome by improving the abundance and number of lactobacilli and other indigenous probiotic bacteria. Dominant indigenous probiotic bacteria could improve piglets' growth and immunity through certain cascade signal transduction pathways. The piglet body provides a permissive habitat and nutrients for bacterial colonization and growth. In return, probiotic bacteria produce prebiotics such as short-chain fatty acids and bacteriocins that benefit piglets by enhancing their growth and reducing their risk of enteric infection by pathogens. A comprehensive understanding of the interactions between piglets and members of their gut microbiota will help develop new dietary interventions that can enhance piglets' growth, protect piglets from enteric diseases caused by pathogenic bacteria, and maximize host feed utilization.

Qualitative modelling of the interplay of inflammatory status and butyrate in the human gut: a hypotheses about robust bi-stability

Background

Gut microbiota interacts with the human gut in multiple ways. Microbiota composition is altered in inflamed gut conditions. Likewise, certain microbial fermentation products as well as the lipopolysaccharides of the outer membrane are examples of microbial products with opposing influences on gut epithelium inflammation status. This system of intricate interactions is known to play a core role in human gut inflammatory diseases. Here, we present and analyse a simplified model of bidirectional interaction between the microbiota and the host: in focus is butyrate as an example for a bacterial fermentation product with anti-inflammatory properties.

Results

We build a dynamical model based on an existing model of inflammatory regulation in gut epithelial cells. Our model introduces both butyrate as a bacterial product which counteracts inflammation, as well as bacterial LPS as a pro-inflammatory bacterial product. Moreover, we propose an extension of this model that also includes a feedback interaction towards bacterial composition. The analysis of these dynamical models shows robust bi-stability driven by butyrate concentrations in the gut. The extended model hints towards a further possible enforcement of the observed bi-stability via alteration of gut bacterial composition. A theoretical perspective on the stability of the described switch-like character is discussed.

Conclusions

Interpreting the results of this qualitative model allows formulating hypotheses about the switch-like character of inflammatory regulation in the gut epithelium, involving bacterial products as constitutive parts of the system. We also speculate about possible explanations for observed bimodal distributions in bacterial compositions in the human gut. The switch-like behaviour of the system proved to be mostly independent of parameter choices. Further implications of the qualitative character of our modeling approach for the robustness of the proposed hypotheses are discussed, as well as the pronounced role of butyrate compared to other inflammatory regulators, especially LPS, NF- κB and cytokines.

Electronic supplementary material

The online version of this article (10.1186/s12918-018-0667-6) contains supplementary material, which is available to authorized users.

Disease-Specific Enteric Microbiome Dysbiosis in Inflammatory Bowel Disease

Inflammatory Bowel disease (IBD) is traditionally divided into Crohn's disease (CD) and ulcerative colitis (UC). UC is a relapsing non-transmural inflammatory disease that is restricted to the colon and is characterized by flare-ups of bloody diarrhea. CD is a chronic, segmental localized granulomatous disease that can affect any part of the entire gastrointestinal tract. Ileo-anal pouch is a procedure restoring functionality of the rectum after a colectomy. IBD is a multifactorial disease and flares of IBD are probably triggered by changes in the intestinal microbiota followed by an abnormal immune response. In this study, we aim to analyze the intestinal bacterial diversity in IBD patients during various stages of disease compared with healthy controls. Permission for human experiments and recruitment of participants was obtained from the Ethic Committee for Copenhagen County hospitals (Permission no. KA-03019, Permission no. KA-20060159). Stools from 26 healthy controls, 42 CD, 38 UC and 18 pouch patients were collected. Stool DNA extraction was performed using Qiagen, DNA mini stool kit Denmark. DGGE-PCR amplifying the V2-V3 region of 16S-rDNA gene of the bacteria was amplified by universal primers HDA1 and HDA2. Analysis of DGGE was performed blinded using BioNumerics version 7.5. After normalization, a DGGE gel band matching was performed. The similarities between profiles were calculated with a ranked Pearson correlation coefficient based on the band matching results using band intensities. Simpson's index of diversity and Pielou's species evenness were calculated. Based on the Shannon Diversity Index, UC patients had lower species diversity and bacterial evenness in comparison to healthy persons, p < 0.05. However, only CD and disease pouch patients had lower species diversity compared to those with inactive disease and healthy controls. Well-functioning pouch patients had decreased species evenness in comparison to diseased pouch patients and control group. During the active disease stage in CD and pouch, the patients have a low bacterial diversity in their gut when compared to the inactive stage. In UC patients, a generally low diversity was observed at all stages of the disease compared to healthy controls.

Gut dysbiosis and paediatric Crohn's disease

OBJECTIVES

The main objective of this manuscript is to discuss our present knowledge of the relationships between dysbiosis and paediatric Crohn's disease (CD). The therapeutic role of the methods currently used to re-establish normal gut microbiota composition is also analysed.

METHODS

PubMed was used to search for all of the studies published from January 2008 to June 2018 using the key words: "Crohn's disease" and "gut dysbiosis" or "microbiota" or "microbioma" or "probiotic" and "children" or "paediatric". More than 100 articles were found, but only those published in English or providing evidence-based data were included in the evaluation.

RESULTS

Gut microbiota are primary actors in CD's pathogenesis. The new techniques developed in metagenomics allow us to reveal new details of microbiota composition in healthy subjects and CD patients, and to elucidate the link between microbiota and numerous pathologies, such as obesity, allergies and type 1 diabetes mellitus.

CONCLUSION

Discoveries on the role of gut microbiota could potentially disclose new therapeutic options for CD treatment and improve the existing therapies. Further studies are needed to facilitate the diagnosis and tailor the therapy of a pathology that is an increasing burden on public health.

Sodium butyrate improves antioxidant stability in sub-acute ruminal acidosis in dairy goats

Background

Currently, little is known about the effect of sodium butyrate (NaB) on oxidative stress following grain-induced sub-acute ruminal acidosis in dairy goats. In the present study, 18 lactating dairy goats implanted with a ruminal cannula and permanent indwelling catheters in the portal and hepatic veins were randomly allocated into 3 treatment groups over 20 weeks: low grain (LG, 40% grain; n = 6), high grain (HG, 60% grain; n = 6) and high grain with sodium butyrate (HG + NaB, 60% grain + NaB; n = 6).

Results

When added to the HG diet, NaB increased the mean ruminal pH and reduced the levels of ruminal, portal and hepatic LPS; Additionally, we observed an increase in SOD1, SOD2, SOD3, GPX1 and CAT mRNA expression, increased levels of TSOD and CAT enzyme activity as well as increased total antioxidant capacity (T-AOC) and decreased malondialdehyde (MDA) in both the liver and plasma, while GPx activity increased in the liver of goats fed the HG + NaB diet. The mRNA expression of UGT1A1, NQO1, MGST3, and Nrf2, as well as total Nrf2 protein levels were increased in goats fed the HG + NaB diet.

Conclusions

Our study indicates that sodium butyrate could improve the oxidative status in sub-acute ruminal acidosis through the partial activation of Nrf2-dependent genes.

The surgical treatment of acute and severe diversion colitis mimicking ulcerative colitis: a case report

BACKGROUND

Diversion colitis (DC) is characterized by nonspecific inflammation in the remaining colon or rectum, and loss of the fecal stream plays a major role in the disease's development. Although the majority of patients are asymptomatic, medical and/or surgical treatment is required for those who are symptomatic. There is a particular interest on how to manage patients with acute and severe clinical presentations, but the pathogenesis is not fully understood. We report the rare case of a man with acute and severe DC mimicking ulcerative colitis (UC) with extra-intestinal manifestations that was successfully managed with surgical treatment.

CASE PRESENTATION

A 68-year-old man with a history of laparoscopic intersphincteric resection of the rectum with diverting loop ileostomy for lower rectal cancer suffered from anastomotic stenosis requiring repeated endoscopic dilatation. His loop stoma was not reversed because these treatments were unsuccessful. He denied having a history of inflammatory bowel disease. Twelve years postoperatively, he developed a perineal abscess requiring drainage. Subsequently, he developed a high-grade fever, bloody discharge per anus, and skin ulcers in the right ankle and around the stoma. Because culture tests were negative for bacteria, it was deemed that his acute illness reflected an inflammatory response rather than an infectious disease. Colonoscopy revealed anastomotic stenosis, a colonic fistula, and mucosa that hemorrhaged easily, with lacerations. A pathological examination with biopsy revealed inflammatory infiltration without malignancy. After reviewing the patient's clinical episodes and discussing the case with physicians in multiple specialties, we performed total colectomy with end ileostomy in accordance with the abdominoperineal resection. The postoperative course was uneventful. A resected specimen showed atrophic mucosa with the disappearance of haustra in the distal colon, as well as edematous and dilated mucosa in the proximal colon. The pathological diagnosis was suggestive of UC, including erosion and ulceration in edematous wall, crypt abscess, and inflammatory infiltration into the mucosa. The skin ulcers in the right ankle and around the stoma healed over time.

CONCLUSIONS

DC can eventuate in a long-term period after fecal diversion surgery, possibly with extra-intestinal manifestations mimicking UC. Surgical treatment seems feasible for patients with acute and severe DC.

Effects of dietary sodium butyrate on reproduction in adult breeder roosters

Sodium butyrate (SB) is a novel feed additive in poultry production. This study aimed to evaluate the effects of dietary supplementation of SB on the reproductive performance of the rooster. Three hundred 22-week-old roosters were randomly divided into 2 dietary treatment groups of 6 pen replicates, a basal diet (control) group and a basal diet with SB gruop. The supplementation of SB was carried out through 23 consecutive weeks from 22 to 45 weeks of age. During this period, the live-weight was measured weekly while semen samples were collected every two weeks. Three time-points were chosen for analysis (30, 35 and 45 weeks of age). The results showed that SB improved the semen volume and sperm motility at 30 and 35 weeks of age (P < 0.05), increased the sperm concentration and decreased the abnormal sperm percentage during the whole experimental period (P < 0.05). These improvements were accompanied by increased testosterone levels at 30 and 35 weeks of age (P < 0.05). Moreover, dietary supplementation of SB also increased the enzyme activities of glutathione peroxidase (GPx) at 30 and 35 weeks of age and superoxide dismutase (SOD) at 45 weeks of age in the testes of roosters (P < 0.05). These results suggest that SB may promote testicular growth by increasing the antioxidant capacity and testosterone hormone secretion in adult roosters.

Butyrate decreases its own oxidation in colorectal cancer cells through inhibition of histone deacetylases

Colorectal cancer is characterized by an increase in the utilization of glucose and a diminishment in the oxidation of butyrate, which is a short chain fatty acid. In colorectal cancer cells, butyrate inhibits histone deacetylases to increase the expression of genes that slow the cell cycle and induce apoptosis. Understanding the mechanisms that contribute to the metabolic shift away from butyrate oxidation in cancer cells is important in in understanding the beneficial effects of the molecule toward colorectal cancer. Here, we demonstrate that butyrate decreased its own oxidation in cancerous colonocytes. Butyrate lowered the expression of short chain acyl-CoA dehydrogenase, an enzyme that mediates the oxidation of short-chain fatty acids. Butyrate does not alter short chain acyl-CoA dehydrogenase levels in non-cancerous colonocytes. Trichostatin A, a structurally unrelated inhibitor of histone deacetylases, and propionate also decreased the level of short chain acyl-CoA dehydrogenase, which alluded to inhibition of histone deacetylases as a part of the mechanism. Knockdown of histone deacetylase isoform 1, but not isoform 2 or 3, inhibited the ability of butyrate to decrease short chain acyl-CoA dehydrogenase expression. This work identifies a mechanism by which butyrate selective targets colorectal cancer cells to reduce its own metabolism.

Microbial Fermentation of Starch: Its Impact on the Range of Acceptable Carbohydrate Intake

Starch, a major source of carbohydrates in human nutrition, is extensively hydrolyzed in the gastrointestinal tract of children and adults. A small fraction of the ingested starch reaches the cecum and colon where it is fermented by the gut microbiome into short-chain fatty acids (SCFA) and other products. Recent data in humans and in animal models have demonstrated the extensive effects of short-chain fatty acids on whole body energy metabolism, appetite, insulin resistance, fatty acid oxidation, fat accretion, obesity, and diabetes. Clear discernible effects of SCFA on the rates of production of glucose, its oxidation and uptake in the fasting state were, however, not observed. In the fed state, the effects on glucose metabolism are related to the effects of SCFA on insulin sensitivity, possibly the consequence of their influence on lipid metabolism. The suggested limits of carbohydrate intake were based upon the kinetics and metabolism of glucose in the basal state and on the responses to glucose administration. It is postulated that in healthy subjects, the present data do not suggest any significant impact of microbial fermentation of starch on the range of acceptable intake of carbohydrates.

Microbiome-Mediated Effects of the Mediterranean Diet on Inflammation

The Mediterranean diet pattern is increasingly associated with improved metabolic health. Two mechanisms by which consuming a Mediterranean diet pattern may contribute to improved metabolic health are modulation of the gastrointestinal (GI) microbiota and reduction of metabolic endotoxemia. Metabolic endotoxemia, defined as a 2- to 3-fold increase in circulating levels of bacterial endotoxin, has been proposed as a cause of inflammation during metabolic dysfunction. As the largest source of endotoxins in the human body, the GI microbiota represents a crucial area for research on strategies for reducing endotoxemia. Diets high in saturated fat and low in fiber contribute to metabolic endotoxemia through several mechanisms, including changes in the GI microbiome and bacterial fermentation end products, intestinal physiology and barrier function, and enterohepatic circulation of bile acids. Thus, the Mediterranean diet pattern, rich in unsaturated fats and fiber, may be one dietary strategy to reduce metabolic endotoxemia. Preclinical studies have demonstrated the differential effects of dietary saturated and unsaturated fats on the microbiota and metabolic health, but human studies are lacking. The role of dietary fiber and the GI microbiome in metabolic endotoxemia is underinvestigated. Clinical research on the effects of different types of dietary fat and fiber on the GI microbiota and GI and systemic inflammation is necessary to determine efficacious dietary strategies for reducing metabolic endotoxemia, inflammation, and subsequent metabolic disease.

Fecal microbiota transplantation for managing irritable bowel syndrome

Irritable bowel syndrome (IBS) is a widespread gastrointestinal disorder affecting 11.2% of the world adult population. The intestinal microbiome is thought to play a pivotal role in the pathophysiology of IBS. The composition of the fecal microbiome in IBS patients differs from that in healthy individuals, but the exact bacteria species involved in the development of IBS remain to be determined. There is also an imbalance between useful and harmful bacteria (dysbiosis) in the intestinal microbiome in patients with IBS. Consuming prebiotics, probiotics, or synbiotics has a limited effect on IBS symptoms. In contrast, fecal microbiome transplantation (FMT) in IBS patients reverses the dysbiosis to normobiosis and reduces the IBS symptoms in about 70% of patients, and is not associated with any serious adverse events. Area covered: The available data on the microbiome and FMT in IBS regarding the efficacy of FMT in managing IBS were found using a PubMed search of these topics. Expert commentary: FMT is a promising tool for managing irritable syndrome. It appears to be effective, easy, and inexpensive procedure. However, more controlled studies involving larger cohorts of IBS are needed before FMT can be used as a routine procedure in the clinic.

The lectin-like oxidized LDL receptor-1: a new potential molecular target in colorectal cancer

The identification of new biomarkers and targets for tailored therapy in human colorectal cancer (CRC) onset and progression is an interesting challenge. CRC tissue produces an excess of ox-LDL, suggesting a close correlation between lipid dysfunction and malignant transformation. Lectin-like oxidized LDL receptor-1 (LOX-1) is involved in several mechanisms closely linked to tumorigenesis. Here we report a tumor specific LOX-1 overexpression in human colon cancers: LOX-1 results strongly increased in the 72% of carcinomas (P<0.001), and strongly overexpressed in 90% of highly aggressive and metastatic tumours (P<0.001), as compared to normal mucosa. Moreover LOX-1 results modulated since the early stage of the disease (adenomas vs normal mucosa; P<0.001) suggesting an involvement in tumor insurgence and progression. The in vitro knockdown of LOX-1 in DLD-1 and HCT-8 colon cancer cells by siRNA and anti-LOX-1 antibody triggers to an impaired proliferation rate and affects the maintenance of cell growth and tumorigenicity. The wound-healing assay reveals an evident impairment in closing the scratch. Lastly knockdown of LOX-1 delineates a specific pattern of volatile compounds characterized by the presence of a butyrate derivative, suggesting a potential role of LOX-1 in tumor-specific epigenetic regulation in neoplastic cells. The role of LOX-1 as a novel biomarker and molecular target represents a concrete opportunity to improve current therapeutic strategies for CRC. In addition, the innovative application of a technology focused to the identification of LOX-1 driven volatiles specific to colorectal cancer provides a promising diagnostic tool for CRC screening and for monitoring the response to therapy.