Butyrate Levels Research Articles

Partially hydrolyzed guar gum increased colonic mucus layer in mice via succinate-mediated MUC2 production

Colonic mucus layers protect intestinal tissues against intestinal bacteria. We investigated the effects of dietary fiber and its metabolites on mucus production in the colonic mucosa. Mice were fed a partially hydrolyzed guar gum (PHGG)-containing diet and a fiber-free diet (FFD). The colon mucus layer, fecal short-chain fatty acid (SCFA) levels, and gut microbiota were evaluated. Mucin 2 (MUC2) expression was assessed in SCFA-treated LS174T cells. The role of AKT in MUC2 production was investigated. The mucus layer in the colonic epithelium was significantly increased in the PHGG group compared with that in the FFD group. In the PHGG group, an increase in Bacteroidetes in the stool was observed, and fecal acetate, butyrate, propionate, and succinate levels were significantly increased. However, MUC2 production was significantly increased only in succinate-stimulated LS174T cells. The succinate-induced MUC2 production was associated with AKT phosphorylation. Succinate mediated the PHGG-induced increase in the colon mucus layer.

Early life gut microbiota sustains liver-resident natural killer cells maturation via the butyrate-IL-18 axis

Liver-resident natural killer cells, a unique lymphocyte subset in liver, develop locally and play multifaceted immunological roles. However, the mechanisms for the maintenance of liver-resident natural killer cell homeostasis remain unclear. Here we show that early-life antibiotic treatment blunt functional maturation of liver-resident natural killer cells even at adulthood, which is dependent on the durative microbiota dysbiosis. Mechanistically, early-life antibiotic treatment significantly decreases butyrate level in liver, and subsequently led to defective liver-resident natural killer cell maturation in a cell-extrinsic manner. Specifically, loss of butyrate impairs IL-18 production in Kupffer cells and hepatocytes through acting on the receptor GPR109A. Disrupted IL-18/IL-18R signaling in turn suppresses the mitochondrial activity and the functional maturation of liver-resident natural killer cells. Strikingly, dietary supplementation of experimentally or clinically used Clostridium butyricum restores the impaired liver-resident natural killer cell maturation and function induced by early-life antibiotic treatment. Our findings collectively unmask a regulatory network of gut-liver axis, highlighting the importance of the early-life microbiota in the development of tissue-resident immune cells.

Metabolic Difference Analysis of Clostridium cellulovorans Grown on Glucose and Cellulose

As an anaerobic butyrate-producing bacterium, Clostridium cellulovorans can secrete a variety of extracellular enzymes to degrade plant-based cellulose. However, with glucose as the carbon source, it still secretes a large amount of protein in the broth. The metabolism and regulation are obscure and need to be further studied. Hence, in this study, C. cellulovorans was used to conduct fed-batch fermentation of glucose and microcrystalline at pH 7.0 to produce a higher level of butyrate in the bioreactor. It produced 16.8 mM lactate, 22.3 mM acetate, and 132.7 mM butyrate in 72 h during glucose fermentation. In contrast, it produced only 11.5 mM acetate and 93.9 mM butyrate and took 192 h to complete the fermentation with cellulose as the carbon source. Furthermore, there was no lactate detected in the broth. The analysis of carbon source balance and redox balance showed that 57% of the glucose was consumed to form acids in glucose fermentation, while only 47% of the cellulose was used for acid generation in the cellulose fermentation. Meanwhile, a large amount of protein was detected in the fermentation broth in both glucose (0.9 ± 0.1 g/L) and cellulose (1.1 ± 0.2 g/L) fermentation. These results showed that protein was also a main product. C. cellulovorans metabolized glucose to generate intermediate metabolites and reducing powers (NADH and Fdred), then protein and acid synthesis consumed this reducing power to maintain the carbon source balance and redox balance in the cell metabolism. The results of comparative transcriptomics and comparative proteomics also supported the above conclusion. The method of studying the protein during Clostridium species fermentation provides a new perspective for further study on metabolic regulation.

Polyphenols and pectin enriched golden kiwifruit (Actinidia chinensis) alleviates high fructose-induced glucolipid disorders and hepatic oxidative damage in rats: in association with improvement of fatty acids metabolism

This study aimed to investigate the protective effects of fleshes from two Actinidia chinensis (ACF), pericarps from two A. chinensis (ACP), and fleshes with pericarps from two A. chinensis (ACFP) on high fructose (HF)-instigated dyslipidemia, hepatic steatosis, oxidative stress, insulin resistance, and fatty acid metabolism disorders in rats. In general, the above abnormalities were improved after 10 weeks intervention of ACF, ACP, and ACFP. Especially, ACFP considerably ameliorated HF-induced abnormal changes in body weight gain, serum TC, TG, LDL-C and HDL-C levels, as well as serum and hepatic SFAs, MUFAs and PUFAs contents. ACFP also alleviated HF-induced hyperglycemia and hyperinsulinemia, stabilized HF-caused increase in hepatic MDA and serum ALT, AST levels, and restored HF-declined hepatic T-SOD and GSH-Px activities. Besides, histopathology of the liver further endorsed the protective effects of ACFP on hepatocellular injury. Moreover, ACFP increased HF-dropped acetic, propionic and butyric acid levels. Overall, ACFP employs more efficacious protective effects against HF-induced metabolic disorders and liver damage than ACF and ACP. This study delivers a scientific foundation for developing kiwifruit (counting peel)-based dietary supplements for those with glucolipid-metabolic disorders and liver damage.

The pharmacological mechanism of Xiaoyaosan polysaccharide reveals improvement of CUMS-induced depression-like behavior by carbon source-triggered butyrate-producing bacteria.

Here, regulatory effects of Xiaoyaosan polysaccharide on entire intestinal flora and butyrate-producing bacteria were investigated to reveal their pharmacological mechanism serving as bacterial-derived carbon sources for regulating intestinal microecology during the treatment of chronic unpredictable mild stress (CUMS)-induced depression in rats. The effects were measured by analyzing depression-like behavior, intestinal flora, butyrate-producing bacteria diversity, and fecal butyrate content. After intervention, CUMS rats exhibited alleviated depression and increased body weight, sugar water consumption rate, and performance index in the open-field test (OFT). The abundance of dominant phyla, such as Firmicutes and Bacteroidetes, and dominant genera, such as Lactobacillus and Muribaculaceae, was regulated to restore the diversity and abundance of the entire intestinal flora to a healthy level. The polysaccharide enriched the diversity of butyrate-producing bacteria, increased the abundance of the butyrate-producing bacteria Roseburia sp. and Eubacterium sp., reduced the abundance of Clostridium sp., increased the distribution of Anaerostipes sp., Mediterraneibacter sp., and Flavonifractor sp., and subsequently increased the content of butyrate in the intestine. These findings suggest that the Xiaoyaosan polysaccharide alleviates unpredictable mild stress-induced depression-like chronic behavior in rats by regulating the composition and abundance of the entire intestinal flora, restoring the diversity of butyrate-producing bacteria, and increasing the butyrate levels.

Microbiota-gut-adipose axis: butyrate-mediated the improvement effect on inflammatory response and fatty acid oxidation dysregulation attenuates obesity in sleep-restricted mice

BackgroundInsufficient sleep was considered as a substantial cause of obesity. The present study further explored the mechanism whereby sleep restriction (SR)-mediated intestinal dysbiosis induced metabolic disorder and ultimately lead to obesity in mice and the improvement effect of butyrate exerting on it. MethodsA continuous 3 months SR mouse model with or without butyrate supplementation and fecal microbiota transplantation to explore the key role of intestinal microbiota in butyrate improving inflammatory response in inguinal white adipose tissue (iWAT) and fatty acid oxidation dysfunction in brown adipose tissue (BAT), further ameliorating SR-induced obesity. ResultsSR-mediated gut microbiota dysbiosis (down-regulation in butyrate level and up-regulation in LPS level) induced intestinal permeability increase and inflammatory response in iWAT and fatty acid oxidation dysfunction in BAT, ultimately resulting in obesity. Further, we demonstrated butyrate ameliorated gut microbiota homeostasis, suppressed inflammatory response via GPR43/LPS/TLR4/MyD88/GSK-3β/β-catenin loop in iWAT and restored fatty acid oxidation function via HDAC3/PPARα/PGC-1α/UCP1/Calpain1 pathway in BAT, ultimately reversing SR-induced obesity. ConclusionsWe revealed that gut dysbiosis is a key factor for SR-induced obesity and provided a better understanding of the effects of butyrate. We further expected that reversing SR-induced obesity by improving microbiota–gut–adipose axis disorder could be a possible treatment for metabolic diseases.

A264 ORAL IRON SUPPLEMENTATION SHAPES THE RECOVERY OF GUT THE MICROBIOTA AND PROMOTES CARCINOGENESIS IN THE APCMIN/+ MOUSE MODEL

Abstract Background Colorectal cancer (CRC) induces anemia in a large proportion of patients and is usually treated with oral iron supplementation. Surgery, the main treatment for CRC, is routinely accompanied by prophylactic antibiotics to avoid infection. Moreover, the concomitance of oral iron supplementation and antibiotics treatment is highly prevalent in general population. However, the combined effect of antibiotics and high luminal iron concentration in the gut on the microbiota and intestinal homeostasis remains unknown. Purpose This study sought to identify possible deleterious effects of the recovery from antibiotics exposure of the gut microbiota under oral iron supplementation. Method In order to assess the effects of luminal iron on the recovery of the gut microbiota, WT mice were subjected to antibiotic treatment with different concentrations of dietary iron. Then, to explore potential deleterious effects of this setup on CRC promotion and progression mediated by the human CRC gut microbiota, CRC model ApcMin/+ mice were subjected to antibiotics prior to gavage with fecal samples from anemic CRC patients, then fed different concentrations of dietary iron. The composition of the gut microbiota and its recovery after these interventions were assessed in stool samples by 16S rRNA. Gut microbiota functions were inferred by using the PICRUSt2, and short chain fatty acid (SCFA) concentration in feces were assessed by liquid-chromatography mass spectrometry. CRC progression and promotion were assessed by tumour counts and immunohistochemistry. Result(s) Recovery from antibiotics under high luminal iron concentration shifted the gut microbiota toward a Bacteroidetes phylum-dominant composition. Three bacterial species characterized as CRC initiators were significantly more abundant. Nitrogen, pentose phosphate, cyanoamino acid metabolisms were higher after recovery under oral iron supplementation. Antibiotic exposure induced a long-term increase in SCFAs linked to gut inflammation, propionate and succinate. For mice under high luminal iron concentration, they showed a lack of recovery in baseline levels of butyrate, a SCFA that inhibits cancer cell proliferation in the gut. In addition, an increase in CRC burden and progression were found in ApcMin/+ mice receiving fecal sample from patients and oral iron supplementation. Conclusion(s) Gut microbiota recovery from antibiotic exposure under oral iron supplementation is frequent in CRC patients, but is also common in the general population. This study identifies possible deleterious effects of the concomitance of these two disruptive agents of the gut microbiota on the CRC progression. Please acknowledge all funding agencies by checking the applicable boxes below Other Please indicate your source of funding; NSERC, ICM Disclosure of Interest None Declared

Exploiting Underutilised crops

Exploiting Underutilised crops

Potential benefits of a blend of essential oils on metabolism, digestibility, organ development and gene expression of dairy calves

The objective of this study was to evaluate blood cells and metabolites, insulin-like growth factor-1 (IGF-1), digestibility, internal organs weight and histology, gene expression, and spleen cell proliferation of pre-weaned bull calves supplemented with a blend of essential oils in milk replacer (MR). Sixteen newborn Holstein × Gyr crossbred dairy bull calves, with body weight at birth of 33.3 ± 3.7 kg, were housed in individual sand bedded pens, blocked by genetic composition, and randomly assigned to 1 of 2 treatments in a randomized complete block design: Control (CON, n = 8) and blend of essential oils supplementation (BEO, n = 8, 1 g/day/calf, Apex Calf, Adisseo, China). The commercial blend was composed by plant extracts derived from anise, cinnamon, garlic, rosemary, and thyme. Animals were fed 5 L of MR/day reconstituted at 15% (dry matter basis), divided into two equal meals. Water and starter were provided ad libitum. ß-hydroxybutyrate, urea, and glucose were evaluated weekly, IGF-1 was evaluated biweekly, and total blood cell count was performed every four weeks until the end of the trial at eight weeks of age. Feed samples were collected three times a week and polled for weekly analysis. Apparent total nutrient digestibility was determined from d 56 to 60 of age. On d 60 ± 1, animals were euthanized for organ weight, histology, spleen cell proliferation, and intestinal gene expression analysis. Data were analyzed independently using linear mixed models using the REML method in the nlme package in R for continuous outcomes. A non-parametric test was used for ordered categorical outcomes using the Artools package in R. There were no differences between groups for blood evaluations, digestibility, gene expression, and a spleen cell proliferation assay. However, BEO calves presented a heavier pancreas, heavier intestines, bigger ileum villi, and higher cecum butyrate levels (P < 0.05), demonstrating that the EO supplementation helped intestinal development and symbiotic bacteria. It was also observed in CON animals’ heavier respiratory tract and a higher eosinophil count (P < 0.05). Therefore, the organs where eosinophils are more active had a better response for BEO animals. No differences were found in the intestinal gene expression in the immune context. These results demonstrate that supplementing essential oils in MR could contribute to gut development and immune function. However, more research is needed to understand its impact on body development and define the best dosage and route of administration.

Jaboticaba (Myrciaria cauliflora) Fruit Extract Suppressed Aberrant Crypt Formation in 1,2-Dimetylhydrazine-Induced Rats.

Early intervention can significantly improve the colorectal cancer survival rate. Foods rich in phenolic compounds, such as jaboticaba (Myrciaria cauliflora), may prevent tumorigenesis. We investigated the effectivity of jaboticaba whole fruit ethanolic extract (FEX) in suppressing aberrant crypt foci (ACF), the earliest lesion of colorectal cancer (CRC), in 1,2-dimethylhydrazine (DMH)-induced rats and the underlying mechanisms related to the gut microbiota composition and short chain fatty acid (SCFA). This study was approved by the Institutional Animal Care and Use Committee (IACUC) of Providence University (Trial Registration Number 20180419A01, registration date: 22 December 2018). The FEX contains gallic acid and an especially high ellagic acid concentration of 54.41 ± 1.80 and 209.79 ± 2.49mg/100g FEX. The highest total ACF number (150.00 ± 43.86) was recorded in the DMH control (D) group. After 56 days of oral FEX treatment, the total ACF number in the low FEX dosage (DL) group was significantly lower compared to the D group (p < 0.05). The large-sized ACF (> 5 foci), which has a higher probability of progressing to later stage, was significantly decreased in the high FEX dosage (DH) group. The 16s rDNA metagenomic sequencing of the cecal material revealed that the CRC biomarker Lachnoclostridium was significantly suppressed in the DH group (p < 0.05), whereas some SCFA-producing taxa and the cecal butyrate concentration were significantly elevated in the DL and DH groups (p < 0.05). This study demonstrated the potential of jaboticaba whole fruit in CRC prevention, especially in the initial stage, by shifting gut microbiota composition and improving cecal butyrate level.

Butyrate Properties in Immune-Related Diseases: Friend or Foe?

Butyrate is a short-chain fatty acid (SCFA) created within the intestinal lumen by bacterial fermentation of largely undigested dietary carbohydrates. Its beneficial effects on cellular energy metabolism and intestinal homeostasis have garnered significant attention among SCFAs. Butyrate also has systemic effects and is known to regulate the immune system. Most of the butyrate and other SCFAs are produced in the human colon, through the fermentation of dietary fiber or resistant starch. However, the modern diet often lacks sufficient intake of fermentable dietary fiber, which can lead to low butyrate levels in the colon. To increase butyrate levels, it is helpful to incorporate fiber sources into meals and drinks that rely on slow bacterial fermentation. Butyrate is well known for its anti-inflammatory properties and has a range of immune system-related properties. As an agonist for GPR41, GPR43, or GPR109A, butyrate may have anti-inflammatory effects through these receptors’ signaling pathways. Butyrate also serves as an epigenetic regulator, responding to environmental or pharmacological changes by inhibiting HDAC, up-regulating miR-7a-5p, and promoting histone butyrylation and autophagy processes. This review discusses the importance of butyrate in regulating immunological homeostasis and the inflammatory response. It also addresses experimental models and human studies investigating the therapeutic potential of butyrate supplementation in immune-related conditions linked to butyrate depletion. Specifically, it covers the role of butyrate in some immune-related diseases such as systemic lupus erythematosus, atopic dermatitis, psoriasis, human immunodeficiency virus, cancer, and several other special conditions.

Dimethyl itaconate ameliorates cognitive impairment induced by a high-fat diet via the gut-brain axis in mice

BackgroundGut homeostasis, including intestinal immunity and microbiome, is essential for cognitive function via the gut-brain axis. This axis is altered in high-fat diet (HFD)-induced cognitive impairment and is closely associated with neurodegenerative diseases. Dimethyl itaconate (DI) is an itaconate derivative and has recently attracted extensive interest due to its anti-inflammatory effect. This study investigated whether intraperitoneal administration of DI improves the gut-brain axis and prevents cognitive deficits in HF diet-fed mice.ResultsDI effectively attenuated HFD-induced cognitive decline in behavioral tests of object location, novel object recognition, and nesting building, concurrent with the improvement of hippocampal RNA transcription profiles of genes associated with cognition and synaptic plasticity. In agreement, DI reduced the damage of synaptic ultrastructure and deficit of proteins (BDNF, SYN, and PSD95), the microglial activation, and neuroinflammation in the HFD-fed mice. In the colon, DI significantly lowered macrophage infiltration and the expression of pro-inflammatory cytokines (TNF-α, IL-1β, IL-6) in mice on the HF diet, while upregulating the expression of immune homeostasis-related cytokines (IL-22, IL-23) and antimicrobial peptide Reg3γ. Moreover, DI alleviated HFD-induced gut barrier impairments, including elevation of colonic mucus thickness and expression of tight junction proteins (zonula occludens-1, occludin). Notably, HFD-induced microbiome alteration was improved by DI supplementation, characterized by the increase of propionate- and butyrate-producing bacteria. Correspondingly, DI increased the levels of propionate and butyrate in the serum of HFD mice. Intriguingly, fecal microbiome transplantation from DI-treated HF mice facilitated cognitive variables compared with HF mice, including higher cognitive indexes in behavior tests and optimization of hippocampal synaptic ultrastructure. These results highlight the gut microbiota is necessary for the effects of DI in improving cognitive impairment.ConclusionsThe present study provides the first evidence that DI improves cognition and brain function with significant beneficial effects via the gut-brain axis, suggesting that DI may serve as a novel drug for treating obesity-associated neurodegenerative diseases.4a9KXDauVpoNKT93MadQdFVideo

Steering the product spectrum in high-pressure anaerobic processes: CO2 partial pressure as a novel tool in biorefinery concepts

BackgroundElevated CO2 partial pressure (pCO2) has been proposed as a potential steering parameter for selective carboxylate production in mixed culture fermentation. It is anticipated that intermediate product spectrum and production rates, as well as changes in the microbial community, are (in)directly influenced by elevated pCO2. However, it remains unclear how pCO2 interacts with other operational conditions, namely substrate specificity, substrate-to-biomass (S/X) ratio and the presence of an additional electron donor, and what effect pCO2 has on the exact composition of fermentation products. Here, we investigated possible steering effects of elevated pCO2 combined with (1) mixed substrate (glycerol/glucose) provision; (2) subsequent increments in substrate concentration to increase the S/X ratio; and (3) formate as an additional electron donor.ResultsMetabolite predominance, e.g., propionate vs. butyrate/acetate, and cell density, depended on interaction effects between pCO2–S/X ratio and pCO2–formate. Individual substrate consumption rates were negatively impacted by the interaction effect between pCO2–S/X ratio and were not re-established after lowering the S/X ratio and adding formate. The product spectrum was influenced by the microbial community composition, which in turn, was modified by substrate type and the interaction effect between pCO2–formate. High propionate and butyrate levels strongly correlated with Negativicutes and Clostridia predominance, respectively. After subsequent pressurized fermentation phases, the interaction effect between pCO2–formate enabled a shift from propionate towards succinate production when mixed substrate was provided.ConclusionsOverall, interaction effects between elevated pCO2, substrate specificity, high S/X ratio and availability of reducing equivalents from formate, rather than an isolated pCO2 effect, modified the proportionality of propionate, butyrate and acetate in pressurized mixed substrate fermentations at the expense of reduced consumption rates and increased lag-phases. The interaction effect between elevated pCO2 and formate was beneficial for succinate production and biomass growth with a glycerol/glucose mixture as the substrate. The positive effect may be attributed to the availability of extra reducing equivalents, likely enhanced carbon fixating activity and hindered propionate conversion due to increased concentration of undissociated carboxylic acids.

Impact of multiple different high-fat diets on metabolism, inflammatory markers, dysbiosis, and liver histology: study on NASH rat model induced diet

Background: The spectrum of non-alcoholic fatty liver disease (NAFLD), known as non-alcoholic steatohepatitis (NASH), can lead to advanced liver disease. It is known that a variety of diets play a significant role in the development of NAFLD/NASH. The goal of this study was to determine the most appropriate composition of diet to induce NASH in an animal model. Methods: This research used Rattus norvegicus strain Wistar (n=27), which were divided into four groups and given each diet for 12 weeks: normal diet (ND, n=7), high-fat diet (HFD, n=6), western diet (WD, n=7) and high-fat-high-fructose diet (HFHFD, n=7). Subjects were documented for body weight. Blood samples were taken for biochemical analysis: low-density lipoprotein (LDL), triglyceride, alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), hepatic lipase, tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and lipopolysaccharide (LPS). Feces were taken for short-chain fatty acid (SCFA) analysis. Liver histology was analyzed using NAS (NAFLD activity score). The comparison test was carried out using the one-way ANOVA or Kruskal–Wallis test. Results: The highest average body weight was in the WD group (346.14 g). Liver enzymes, LDL, triglyceride, propionic acid, and acetic acid in each group were not significantly different. TNF-α, IL-6, and hepatic lipase were significant (p = 0.000; p = 0.000; p = 0.004) and the highest was in the HFD group. Butyrate level was significant (p = 0.021) and the least was in the HFHFD group (4.77 mMol/g). Only WD and HFHFD had an NAS ≥ 5 (14% and 14%). The highest percentage of borderline NAS was found in WD (57%). Conclusions: The HFD group showed significant liver inflammation but did not produce NASH histologically, whereas the WD and HFHFD groups had the potential to develop NASH because the diets affected metabolic and inflammatory parameters as well as liver histology.

Yeast Cell Wall Compounds on The Formation of Fermentation Products and Fecal Microbiota in Cats: An In Vivo and In Vitro Approach.

The effects of yeast cell wall compounds (YCWs) being added to cat food on hindgut fermentation metabolites and fecal microbiota were assessed in in vivo Experiment 1 (Exp. 1) and in vitro Experiments 2 and 3 (Exp. 2 and 3). In Exp. 1, the cats' diets were supplemented with two dietary concentrations (46.2 and 92.4 ppm) of YCWs (YCW-15 and YCW-30, respectively), and a negative control diet with no compound in three groups (six cats per group) was used to assess the fecal score, pH, digestibility, fermentation products, and microbiota. In Exp. 2, feces from the cats that were not supplemented with YCWs (control) were used as an inoculum. A blend of pectin, amino acids, and cellulose was used as a substrate, and the YCW compound was added at two levels (5 and 10 mg). In Exp. 3, feces from cats fed YCWs were used as an inoculum to test three different substrates (pectin, amino acids, and cellulose). In Exp. 2 and 3, the gas production, pH, and fermentation products (ammonia, SCFAs, and BCFAs) were assessed. YCW-30 resulted in a higher digestibility coefficient of the crude protein, organic matter (OM) (p < 0.05), and energy of the diet (p < 0.10). Regarding the fermentation products, YCW-15 showed a trend toward higher concentrations of propionate, acetate, lactate, ammonia, isobutyrate, and valerate, while YCW-30 showed a trend (p < 0.10) toward higher levels of butyrate and pH values. The bacteroidia class and the genus Prevotella were increased by using YCW-30 and the control. At the gender level, decreased (p < 0.01) Megasphaera was observed with YCW inclusion. The microbiota differed (p < 0.01) among the groups in their Shannon indexes. For beta diversity, YCW-30 showed higher indexes (p = 0.008) than the control. The microbiota metabolic profile differed in the pathway CENTFERM-PWY; it was more expressed in YCW-30 compared to the control. In Exp. 2, the YCWs showed a higher ratio (p = 0.006) of the fermentation products in the treatments with additives with a trend towards a high dose of the additive (10 mg). In Exp. 3, the effects of the substrates (p < 0.001), but not of the YCWs, on the fermentation products were observed, perhaps due to the low dietary concentrations we used. However, the marked responses of the fermentation products to the substrates validated the methodology. We could conclude that the YCWs, even at low dietary concentrations, affected fecal SCFA production, reduced the fecal pH, and modulated the fecal microbiota in the cats. These responses were more pronounced under in vitro conditions.

Type I Diabetes Pathoetiology and Pathophysiology: Roles of the Gut Microbiome, Pancreatic Cellular Interactions, and the 'Bystander' Activation of Memory CD8+ T Cells.

Type 1 diabetes mellitus (T1DM) arises from the failure of pancreatic β-cells to produce adequate insulin, usually as a consequence of extensive pancreatic β-cell destruction. T1DM is classed as an immune-mediated condition. However, the processes that drive pancreatic β-cell apoptosis remain to be determined, resulting in a failure to prevent ongoing cellular destruction. Alteration in mitochondrial function is clearly the major pathophysiological process underpinning pancreatic β-cell loss in T1DM. As with many medical conditions, there is a growing interest in T1DM as to the role of the gut microbiome, including the interactions of gut bacteria with Candida albicans fungal infection. Gut dysbiosis and gut permeability are intimately associated with raised levels of circulating lipopolysaccharide and suppressed butyrate levels, which can act to dysregulate immune responses and systemic mitochondrial function. This manuscript reviews broad bodies of data on T1DM pathophysiology, highlighting the importance of alterations in the mitochondrial melatonergic pathway of pancreatic β-cells in driving mitochondrial dysfunction. The suppression of mitochondrial melatonin makes pancreatic β-cells susceptible to oxidative stress and dysfunctional mitophagy, partly mediated by the loss of melatonin's induction of PTEN-induced kinase 1 (PINK1), thereby suppressing mitophagy and increasing autoimmune associated major histocompatibility complex (MHC)-1. The immediate precursor to melatonin, N-acetylserotonin (NAS), is a brain-derived neurotrophic factor (BDNF) mimic, via the activation of the BDNF receptor, TrkB. As both the full-length and truncated TrkB play powerful roles in pancreatic β-cell function and survival, NAS is another important aspect of the melatonergic pathway relevant to pancreatic β-cell destruction in T1DM. The incorporation of the mitochondrial melatonergic pathway in T1DM pathophysiology integrates wide bodies of previously disparate data on pancreatic intercellular processes. The suppression of Akkermansia muciniphila, Lactobacillus johnsonii, butyrate, and the shikimate pathway-including by bacteriophages-contributes to not only pancreatic β-cell apoptosis, but also to the bystander activation of CD8+ T cells, which increases their effector function and prevents their deselection in the thymus. The gut microbiome is therefore a significant determinant of the mitochondrial dysfunction driving pancreatic β-cell loss as well as 'autoimmune' effects derived from cytotoxic CD8+ T cells. This has significant future research and treatment implications.

In Vitro Fermentation of Edible Mushrooms: Effects on Faecal Microbiota Characteristics of Autistic and Neurotypical Children

Children with autism spectrum disorder (ASD) often suffer gastrointestinal disturbances consistent with gut microbiota (GM) alterations. Treatment with pro/prebiotics may potentially alleviate gut symptoms, but the evidence for prebiotics is scarce. This study aims to evaluate the effects of edible mushrooms (Pleurotus, Basidiomycota) and prebiotic compounds on GM composition and metabolite production in vitro, using faecal samples from autistic and non-autistic children. Specific microbial populations were enumerated after 24 h of fermentation by quantitative PCR, and the metabolic production was determined by gas chromatography. Higher levels of Prevotella spp. and Bifidobacterium spp. were measured in neurotypical children compared to ASD children. A total of 24 h fermentation of Pleurotus eryngii and P. ostreatus mushroom powder increased the levels of Bifidobacterium, while known prebiotics increased the levels of total bacteria and Bacteroides in both groups. Only P. eryngii mushrooms resulted in significantly elevated levels of total bacteria Bacteroides and Feacalibacterium prausnitzii compared to the negative control (NC) in the ASD group. Both mushrooms induced elevated levels of butyrate after 24 h of fermentation, while short-chain fructooligosaccharides induced increased levels of acetate in the ASD group, compared to NC. Overall, this study highlights the positive effect of edible mushrooms on the GM and metabolic activity of children with ASD.

Anxiolytic- and antidepressant-like effects of Bacillus coagulans Unique IS-2 mediate via reshaping of microbiome gut-brain axis in rats.

Due to the rising cases of treatment-refractory affective disorders, the discovery of newer therapeutic approaches is needed. In recent times, probiotics have garnered notable attention in managing stress-related disorders. Herein, we examined the effect of Bacillus coagulans Unique IS-2® probiotic on anxiety- and depression-like phenotypes employing maternal separation (MS) and chronic-unpredictable mild stress (CUMS) model in rats. Both male and female Sprague-Dawley rats were subjected to MS+CUMS. Probiotic treatment was provided for 6 weeks via drinking water. Anxiety- and depression-like phenotypes were assessed using sucrose-preference test (SPT), forced-swimming test (FST), elevated-plus maze test (EPM), and open-field test (OFT). Blood, brain, intestine, and fecal samples were obtained for biochemical and molecular studies. Stress-exposed rats drank less sucrose solution, showed increased passivity, and explored less in open-arms in SPT, FST, and EPM, respectively. These stress-generated neurobehavioral aberrations were alleviated by 6-week of Bacillus coagulans Unique IS-2 treatment. The overall locomotor activity in OFT remained unchanged. The decreased levels of BDNF and serotonin and increased levels of C-reactive protein, TNF-α, IL-1β, and dopamine, in the hippocampus and/or frontal cortex of stress-exposed rats were reversed following probiotic treatment. Administration of probiotic also restored the systemic levels of L-tryptophan, L-kynurenine, kynurenic-acid, and 3-hydroxyanthranilic acid, villi/crypt ratio, goblet-cell count, Firmicutes to Bacteroides ratio, and levels of acetate, propionate, and butyrate in fecal samples. These results indicate remodeling of the microbiome gut-brain axis in Bacillus coagulans Unique IS-2 recipient rats. However, protein levels of doublecortin, GFAP, and zona occludens in the hippocampus and occludin-immunoreactivity in the intestine remained unchanged. No prominent sex-specific changes were noted. Anxiolytic- and antidepressant-like effects of Bacillus coagulans Unique IS-2 in MS+CUMS rat model may be mediated via reshaping the microbiome gut-brain axis.

Microbiota-derived metabolites in colorectal cancer patients in preoperative period.

Short-chain fatty acids (SCFAs) are microbial derived metabolites, which have multiple beneficial properties. The amount of SCFAs depends on several factors, such as age, diet (mainly intake of dietary fiber), and overall health condition. The normal proportion between SCFAs is 3:1:1 for acetate, proprionate and butyrate, respectively. In colorectal cancer (CRC) patients, microbiota alterations have been shown. Consequently, metabolome within the gut might change to a large extent. Therefore, the aim of this study was to analyse the content of SCFAs and the proportion between SCFAs in the stool obtained from CRC patients in preoperative period. This study included 15 patients with CRC in preoperative period. The stool samples were taken and stored at -80°C in the Fahrenheit Biobank BBMRI.pl, Medical University of Gdansk, Poland. The analysis of SCFAs from stool samples was conducted by means of gas chromatography. This study included mainly males (66.67%, n=10). In all patients, there was abnormal proportion between SCFAs. The extremely higher concentration of butyrate was noted in 2 samples (13.33%) compared to the rest of patients. However, based on normal proportion between SCFAs, the results <1 for butyrate were noted in 93.33% of patients. SCFAs pool is altered in CRC patients, among others characterized by low level of butyrate. It should be considered to administer butyrate supplementation to CRC patients especially prior to surgery to support an appropriate preparation to this treatment.

Characterization and in vitro digestion of rice starch/konjac glucomannan complex prepared by screw extrusion and its impact on gut microbiota

In this paper, we prepared a series of rice starch complexed with various konjac glucomannan (KGM) contents under screw extrusion. The complex's multiscale structures, rheological and thermal properties, and in vitro digestion were explored. The complex's effects on short-chain fatty acids production and gut microbiota composition were further investigated using in vitro human fecal fermentation. Multi-scale structural analysis indicated that short-ordered degree, single/double helix structure contents, and crystallinity of the rice starch increased with an increased concentration of KGM. Rheology and differential scanning calorimeter analysis indicated that KGM enhanced the viscoelasticity of rice starch paste and the thermal stability of rice starch. In vitro digestion data revealed that as KGM concentrations increased, both slowly digested component (SDC) and resistant component (RC) contents increased. This phenomenon was ascribed to the complexation of KGM with rice starch assisted by screw extrusion. Further, the high RC content of the complex contributed to the yield of butyrate level, corresponding to the growth in Actinobacteria at the phylum level, and Megasphaera and Bifidobacterium at the genus level in the cultures. Overall, this research will be critical in determining the physicochemical properties and fecal fermentation behaviors of the rice starch–KGM complex and creating starchy foods with specific health benefits. • Rice starch/Konjac glucomannan (KGM) complex was prepared by screw extrusion. • KGM improved the functional properties of the rice starch during screw extrusion. • Rice starch-KGM complexes presented a slow fermentation rate and similar SCFAs yields. • The complex altered the metabolome, and the changes correlated with those in gut microbiota.