Maltodextrin, Modern Stressor of the Intestinal Environment

Inflammation-Associated Stem Cells in Gastrointestinal Cancers: Their Utility as Prognostic Biomarkers and Therapeutic Targets

Stem cells are critical for the development and homeostasis of the gastrointestinal (GI) tract. Inflammatory molecules are known to regulate the activity of stem cells. A comprehensive review specifically describing the role of inflammatory molecules in the regulation of stem cells within the GI tract and in GI cancers (GICs) is not available. This review focuses on understanding the role of inflammatory molecules and stem cells in maintaining homeostasis of the GI tract. We further discuss how inflammatory conditions contribute to the transformation of stem cells into tumor-initiating cells. We also describe the molecular mechanisms of inflammation and stem cell-driven progression and metastasis of GICs. Furthermore, we report on studies describing the prognostic value of cancer stem cells and the clinical trials evaluating their therapeutic utility. This review provides a detailed overview on the role of inflammatory molecules and stem cells in maintaining GI tract homeostasis and their implications for GI-related malignancies.

Development of Novel High and Low Emulsifier Diets Based upon Emulsifier Distribution in the Australian Food Supply for Intervention Studies in Crohn's Disease

BACKGROUND

The aims of this study were to develop and evaluate a high/low-emulsifier diet and compare emulsifier content with preclinical studies that have associated Crohn's disease with emulsifiers.

METHODS

Supermarkets were audited with a seven-day high- (HED) and low-emulsifier diet (LED) meal plan developed. The emulsifier content of food was sought from food manufacturers, compared to acceptable daily intake (ADI), and doses were provided in trials. Nutritional composition analysis was completed. Healthy adults ate these diets for seven days in a randomized single-blinded cross-over feeding study to assess palatability, tolerability, satiety, food variety, dietary adherence, blinding and the ease of following the meal plan via visual analogue scale.

RESULTS

A database of 1680 foods was created. There was no difference in nutritional content between the HED and LED, except HED had a higher ultra-processed food content (p < 0.001). The HED contained 41 emulsifiers, with 53% of the products able to be quantified for emulsifiers (2.8 g/d), which did not exceed the ADI, was similar to that in observational studies, and was exceeded by doses used in experimental studies. In ten participants, diets were rated similarly in palatability-HED mean 62 (5% CI 37-86) mm vs. LED 68 (54-82) mm-in tolerability-HED 41 (20-61) mm vs. LED 55 (37-73) mm-and in satiety HED 57 (32-81) mm vs. LED 49 (24-73) mm. The combined diets were easy to follow (82 (67-97) mm) with good variety (65 (47-81)) and excellent adherence.

CONCLUSION

Nutritionally well-matched HED and LED were successfully developed, palatable and well tolerated.

Different Approaches to Ergogenic, Pre-, and Probiotic Supplementation in Sports with Different Metabolism Characteristics: A Mini Review

Sport disciplines with different metabolic characteristics require different dietary approaches. Bodybuilders or sprinters ("anaerobic" athletes) need a high-protein diet (HPD) in order to activate muscle protein synthesis after exercise-induced muscle damage and use nitric oxide enhancers (such as citrulline and nitrates) to increase vasodilatation, whereas endurance athletes, such as runners or cyclists ("aerobic" athletes), prefer a high-carbohydrate diet (HCHD), which aims to restore the intramuscular glycogen, and supplements containing buffering agents (such as sodium bicarbonate and beta-alanine). In both cases, nutrient absorption, neurotransmitter and immune cell production and muscle recovery depend on gut bacteria and their metabolites. However, there is still insufficient data on the impact of an HPD or HCHD in addition to supplements on "anaerobic" and "aerobic" athletes' gut microbiota and how this impact could be affected by nutritional interventions such as pre- and probiotic therapy. Additionally, little is known about the role of probiotics in the ergogenic effects of supplements. Based on the results of our previous research on an HPD in amateur bodybuilders and an HCHD in amateur cyclists, we reviewed human and animal studies on the effects of popular supplements on gut homeostasis and sport performance.

Encapsulating Calendula arvensis (Vaill.) L. Florets: UHPLC-HRMS Insights into Bioactive Compounds Preservation and Oral Bioaccessibility

Wild edible plants, once consumed in times of famine or for health purposes, today represent an interesting dietary supplement, aimed at enriching local dishes and/or formulating healthy nutraceutical products. In fact, the broad content of different, and diversely bioactive, specialized metabolites therein suggests new scenarios of use which, in order to be as functional as possible, must maximize the bioactivity of these compounds while preserving their chemistry. In this context, based on a recent investigation on the metabolic profile of the organs of Calendula arvensis that highlighted that florets are abundant in flavonol glycosides and triterpene saponins, the freeze-drying encapsulation of their alcoholic extract (FE) into maltodextrin (MD) was investigated. FE-MD chemical composition was evaluated using Fourier Transform InfraRed spectroscopy (FTIR), while ultra-high performance liquid chromatography coupled with high-resolution tandem mass spectrometry (UHPLC-HRMS/MS) techniques were employed to unravel FE compound preservation also during in vitro simulated digestion. The establishment of H-bonds between FE compounds and MD hydroxyl groups was in line with FE-MD biocompatibility in Caco-2 cells, while in vitro digestion mostly affected structural integrity and/or diversity. Flavonol compounds underwent deglycosylation and demethylation, while deacylation, beyond oxidation, involved triterpene saponins, which massively preserve their aglycone core.

Raising the Alarm: Environmental Factors in the Onset and Maintenance of Chronic (Low-Grade) Inflammation in the Gastrointestinal Tract

Chronic inflammatory disease of the gastrointestinal (GI) tract is defined by several pathophysiological characteristics, such as dysbiosis of the microbiota, epithelial barrier hyperpermeability, systemic dissemination of endotoxins and chronic inflammation. In addition to well-reported environmental factors in non-communicable disease, such as smoking, diet, and exercise, humans are frequently exposed to myriads more environmental factors, from pesticides to food additives. Such factors are ubiquitous across both our diet and indoor/outdoor environments. A major route of human exposure to these factors is ingestion, which frequently occurs due to their intentional addition (intentional food additives) and/or unintentional contamination (unintentional food contaminants) of food products-often linked to environmental pollution. Understanding how this persistent, diverse exposure impacts GI health is of paramount importance, as deterioration of the GI barrier is proposed to be the first step towards systemic inflammation and chronic disease. Therefore, we aim to evaluate the impact of ingestion of environmental factors on inflammatory processes in the GI tract. In this review, we highlight human exposure to intentional food additives (e.g. emulsifiers, bulking agents) and unintentional food contaminants (e.g. persistent organic pollutants, pesticides, microplastics), then present evidence for their association with chronic disease, modification of the GI microbiota, increased permeability of the GI barrier, systemic dissemination of endotoxins, local (and distal) pro-inflammatory signalling, and induction of oxidative stress and/or endoplasmic reticulum stress. We also propose a link to NLRP3-inflammasome activation. These findings highlight the contribution of common environmental factors towards deterioration of GI health and the induction of pathophysiology associated with onset and maintenance of chronic inflammation in the GI tract.

Artificial Sweeteners: History and New Concepts on Inflammation

Since the introduction of artificial sweeteners (AS) to the North American market in the 1950s, a growing number of epidemiological and animal studies have suggested that AS may induce changes in gut bacteria and gut wall immune reactivity, which could negatively affect individuals with or susceptible to chronic inflammatory conditions such as inflammatory bowel disease (IBD), a disorder that has been growing exponentially in westernized countries. This review summarizes the history of current FDA-approved AS and their chemical composition, metabolism, and bacterial utilization, and provides a scoping overview of the disease mechanisms associated with the induction or prevention of inflammation in IBD. We provide a general outlook on areas that have been both largely and scarcely studied, emerging concepts using silica, and describe the effects of AS on acute and chronic forms of intestinal inflammation.

Ingestion of probiotic (Lactobacillus helveticus and Bifidobacterium longum) alters intestinal microbial structure and behavioral expression following social defeat stress

Social stress exacerbates anxious and depressive behaviors in humans. Similarly, anxiety- and depressive-like behaviors are triggered by social stress in a variety of non-human animals. Here, we tested whether oral administration of the putative anxiolytic probiotic strains Lactobacillus helveticus R0052 and Bifidobacterium longum R0175 reduces the striking increase in anxiety-like behavior and changes in gut microbiota observed following social defeat stress in Syrian hamsters. We administered the probiotic at two different doses for 21 days, and 16S rRNA gene amplicon sequencing revealed a shift in microbial structure following probiotic administration at both doses, independently of stress. Probiotic administration at either dose increased anti-inflammatory cytokines IL-4, IL-5, and IL-10 compared to placebo. Surprisingly, probiotic administration at the low dose, equivalent to the one used in humans, significantly increased social avoidance and decreased social interaction. This behavioral change was associated with a reduction in microbial richness in this group. Together, these results demonstrate that probiotic administration alters gut microbial composition and may promote an anti-inflammatory profile but that these changes may not promote reductions in behavioral responses to social stress.

Probiotic consumption relieved human stress and anxiety symptoms possibly via modulating the neuroactive potential of the gut microbiota

Stress has been shown to disturb the balance of human intestinal microbiota and subsequently causes mental health problems like anxiety and depression. Our previous study showed that ingesting the probiotic strain, Lactobacillus (L.) plantarum P-8, for 12 weeks could alleviate stress and anxiety of stressed adults. The current study was a follow-up work aiming to investigate the functional role of the gut metagenomes in the observed beneficial effects. The fecal metagenomes of the probiotic (n = 43) and placebo (n = 36) receivers were analyzed in depth. The gut microbiomes of the placebo group at weeks 0 and 12 showed a significantly greater Aitchison distance (P < 0.001) compared with the probiotic group. Meanwhile, the Shannon diversity index of the placebo group (P < 0.05) but not the probiotic group decreased significantly at week 12. Additionally, significantly more species-level genome bins (SGBs) of Bifidobacterium adolescentis, Bifidobacterium longum, and Fecalibacterium prausnitzii (P < 0.01) were identified in the fecal metagenomes of the probiotic group, while the abundances of SGBs representing the species Roseburia faecis and Fusicatenibacter saccharivorans decreased significantly (P < 0.05). Furthermore, the 12-week probiotic supplementation enhanced the diversity of neurotransmitter-synthesizing/consuming SGBs and the levels of some predicted microbial neuroactive metabolites (e.g., short-chain fatty acids, gamma-aminobutyric acid, arachidonic acid, and sphingomyelin). Our results showed a potential link between probiotic-induced gut microbiota modulation and stress/anxiety alleviation in stressed adults, supporting that the gut-brain axis was involved in relieving stress-related symptoms. The beneficial effect relied not only on microbial diversity changes but more importantly gut metagenome modulations at the SGB and functional gene levels.

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Stress and anxiety are related to gut dysbiosis.

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Ingesting Lactobacillus plantarum P-8 (P-8) improved stress/anxiety symptoms.

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Symptoms were relieved by modulating gut microbiota and neuroactive potential.

Effects of dietary fibre intake in chemotherapy-induced mucositis in murine model

Mucositis is an inflammation of the gastrointestinal mucosa resulting from high doses of radio/chemotherapy treatment and may lead to interruption of antineoplasic therapy. Soluble fibres, like pectin, increase SCFA production, which play a role in gut homoeostasis and inflammation suppression. Due to the properties of pectin, the aim of the present study was to evaluate the effect of a high-fibre (HF) diet on chemotherapy-induced mucositis in a murine model. C57/BL6 mice received control (AIN93M), HF, low/zero fibre (LF) diets for 10 d prior to mucositis challenging with irinotecan (75 mg/kg), or they were treated with acetate added to drinking water 5 d prior to and during the mucositis induction. Mice that received the HF diet showed decreased immune cells influx and improved histopathological parameters in the intestine, compared with mice that received the normal diet. Furthermore, the HF diet decreased intestinal permeability induced in the mucositis model when compared with the control group. This effect was not observed for acetate alone, which did not improve gut permeability. For instance, mice that received the LF diet had worsened gut permeability, compared with mice that received the normal diet and mucositis. The effects of the HF and LF diets were shown to modulate the intestinal microbiota, in which the LF diet increased the levels of Enterobacteriaceae, a group associated with gut inflammation, whereas the HF diet decreased this group and increased Lactobacillus and Bifidobacterium (SCFA producers) levels. In conclusion, the results demonstrated the importance of dietary fibre intake in the modulation of gut microbiota composition and homoeostasis maintenance during mucositis in this model.

Relative abundance of the Prevotella genus within the human gut microbiota of elderly volunteers determines the inter-individual responses to dietary supplementation with wheat bran arabinoxylan-oligosaccharides

BACKGROUND

The human colon is colonised by a dense microbial community whose species composition and metabolism are linked to health and disease. The main energy sources for colonic bacteria are dietary polysaccharides and oligosaccharides. These play a major role in modulating gut microbial composition and metabolism, which in turn can impact on health outcomes.

RESULTS

We investigated the influence of wheat bran arabinoxylan oligosaccharides (AXOS) and maltodextrin supplements in modulating the composition of the colonic microbiota and metabolites in healthy adults over the age of 60. Male and female volunteers, (n = 21, mean BMI 25.2 ± 0.7 kg/m2) participated in the double-blind, cross over supplement study. Faecal samples were collected for analysis of microbiota, short chain fatty acids levels and calprotectin. Blood samples were collected to measure glucose, cholesterol and triglycerides levels. There was no change in these markers nor in calprotectin levels in response to the supplements. Both supplements were well-tolerated by the volunteers. Microbiota analysis across the whole volunteer cohort revealed a significant increase in the proportional abundance of faecal Bifidobacterium species (P ≤ 0.01) in response to AXOS, but not maltodextrin, supplementation. There was considerable inter-individual variation in the other bacterial taxa that responded, with a clear stratification of volunteers as either Prevotella-plus (n = 8; > 0.1% proportional abundance) or Prevotella-minus (n = 13; ≤0.1% proportional abundance) subjects founded on baseline sample profiles. There was a significant increase in the proportional abundance of both faecal Bifidobacterium (P ≤ 0.01) and Prevotella species (P ≤ 0.01) in Prevotella-plus volunteers during AXOS supplementation, while Prevotella and Bacteroides relative abundances showed an inverse relationship. Proportional abundance of 26 OTUs, including bifidobacteria and Anaerostipes hadrus, differed significantly between baseline samples of Prevotella-plus compared to Prevotella-minus individuals.

CONCLUSIONS

The wheat bran AXOS supplementation was bifidogenic and resulted in changes in human gut microbiota composition that depended on the initial microbiota profile, specifically the presence or absence of Prevotella spp. as a major component of the microbiota. Our data therefore suggest that initial profiling of individuals through gut microbiota analysis should be considered important when contemplating nutritional interventions that rely on prebiotics.

TRIAL REGISTRATION

Clinical trial registration number: NCT02693782 . Registered 29 February 2016 - Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT02693782?term=NCT02693782&rank=1.

Randomised Double-Blind Placebo-Controlled Trial of Inulin with Metronidazole in Non-Alcoholic Fatty Liver Disease (NAFLD)

Background: Non-alcoholic fatty liver disease (NAFLD) can be ameliorated by weight loss although difficult to maintain. Emerging evidence indicates that prebiotics and antibiotics improve NAFLD. Aim: To determine whether inulin supplementation after brief metronidazole therapy is effective in reducing alanine aminotransferase (ALT) and maintaining weight loss achieved through a very-low-calorie diet (VLCD) among people with NAFLD. Methods: Sixty-two people with NAFLD commenced 4-week VLCD using Optifast meal replacements (600 kcal/day). Sixty were then randomised into a 12-week double-blind, placebo-controlled, parallel three-arm trial: (1) 400 mg metronidazole twice daily in Week 1 then inulin 4 g twice daily OR (2) placebo twice daily in week one then inulin OR (3) placebo-placebo. Main outcomes were ALT and body weight at 12 weeks. Fecal microbiota changes were also evaluated. Results: Mean body mass index (BMI) and ALT reduced after VLCD by 2.4 kg/m² and 11 U/L, respectively. ALT further decreased after metronidazole-inulin compared to after placebo-placebo (mean ALT change -19.6 vs. -0.2 U/L, respectively; p = 0.026); however, weight loss maintenance did not differ. VLCD treatment decreased the ratio of Firmicutes/Bacteroidetes (p = 0.002). Conclusion: Brief metronidazole followed by inulin supplementation can reduce ALT beyond that achieved after VLCD in patients with NAFLD.

Allicin Modifies the Composition and Function of the Gut Microbiota in Alcoholic Hepatic Steatosis Mice

The intestinal microbiome plays an important role in the pathogenesis of liver diseases. Alcohol intake induces gut microbiota dysbiosis and alters its function. This study investigated the antibiotic effect of allicin in mice with hepatic steatosis. Male C57BL/6 mice were administered an ethanol diet supplemented with allicin (5 and 20 mg/(kg bw day)) for 4 weeks. Allicin modified the gut microbiota composition. Cecal microbiota exhibited a positive correlation with alcohol and hepatic triacylglycerol, but were suppressed with allicin. Ethanol diet with 5 mg of allicin induced a lower intestinal permeability compared to the ethanol diet alone. Allicin mediated the lipopolysaccharide (LPS)-CD14-toll-like receptor 4 (TLR4)-induced hepatic inflammation pathway by reducing LPS, CD14, TLR4, and pro-inflammatory cytokines-tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6. However, hepatic inflammation primarily resulted from alcohol toxicity rather than LPS production in the gut. The prediction of functional profiles from metagenomic 16S ribosomal RNA (rRNA) data revealed different functional profiles in each group. The predicted aldehyde dehydrogenase tended to increase in alcoholic mice administered allicin. The predicted LPS-related pathway and LPS biosynthesis protein results exhibited a similar trend as plasma LPS levels. Thus, alcohol and allicin intake shapes the gut microbiota and its functional profile and improves the CD14-TLR4 pathway to alleviate inflammation in the liver.

Food additives: Assessing the impact of exposure to permitted emulsifiers on bowel and metabolic health - introducing the FADiets study

Emulsifiers are common components of processed foods consumed as part of a Western diet. Emerging in vitro cell-line culture, mouse model and human intestinal tissue explant studies have all suggested that very low concentrations of the food emulsifier polysorbate 80 may cause bacterial translocation across the intestinal epithelium, intestinal inflammation and metabolic syndrome. This raises the possibility that dietary emulsifiers might be factors in conditions such as coronary artery disease, type 2 diabetes and Crohn's disease. The potential mechanism behind the observed effects of this emulsifier is uncertain but may be mediated via changes in the gut microbiota or by increased bacterial translocation, or both. It is also unknown whether these effects are generalisable across all emulsifiers and detergents, including perhaps the natural emulsifier lecithin or even conjugated bile acids, particularly if the latter escape reabsorption and pass through to the distal ileum or colon. A major objective of the Medical Research Council (MRC)-funded Mechanistic Nutrition in Health (MECNUT) Emulsifier project is therefore to investigate the underlying mechanisms and effects of a range of synthetic and natural emulsifiers and detergents in vitro and in vivo, and to determine the effects of a commonly consumed emulsifier (soya lecithin) on gut and metabolic health through a controlled dietary intervention study in healthy human volunteers - the FADiets study. This report provides an overview of the relevant literature, discussing the impact of emulsifiers and other additives on intestinal and metabolic health, and gives an overview of the studies being undertaken as part of the MECNUT Emulsifier project.