Butyrate from bacterial fermentation of germinated barley foodstuff preserves intestinal barrier function in experimental colitis in the rat model

Gut Microbial Metabolite Butyrate and Its Therapeutic Role in Inflammatory Bowel Disease: A Literature Review

Background and objective: Inflammatory bowel disease (IBD), including Crohn's disease and ulcerative colitis, is a chronic inflammatory disorder characterized by aberrant immune responses and compromised barrier function in the gastrointestinal tract. IBD is associated with altered gut microbiota and their metabolites in the colon. Butyrate, a gut microbial metabolite, plays a crucial role in regulating immune function, epithelial barrier function, and intestinal homeostasis. In this review, we aim to present an overview of butyrate synthesis and metabolism and the mechanism of action of butyrate in maintaining intestinal homeostasis and to discuss the therapeutic implications of butyrate in IBD. Methods: We searched the literature up to March 2023 through PubMed, Web of Science, and other sources using search terms such as butyrate, inflammation, IBD, Crohn's disease, and ulcerative colitis. Clinical studies in patients and preclinical studies in rodent models of IBD were included in the summary of the therapeutic implications of butyrate. Results: Research in the last two decades has shown the beneficial effects of butyrate on gut immune function and epithelial barrier function. Most of the preclinical and clinical studies have shown the positive effect of butyrate oral supplements in reducing inflammation and maintaining remission in colitis animal models and IBD patients. However, butyrate enema showed mixed effects. Butyrogenic diets, including germinated barley foodstuff and oat bran, are found to increase fecal butyrate concentrations and reduce the disease activity index in both animal models and IBD patients. Conclusions: The current literature suggests that butyrate is a potential add-on therapy to reduce inflammation and maintain IBD remission. Further clinical studies are needed to determine if butyrate administration alone is an effective therapeutic treatment for IBD.

Dietary fat promotes antibiotic-induced Clostridioides difficile mortality in mice

Clostridioides difficile infection (CDI) is the leading cause of hospital-acquired diarrhea, and emerging evidence has linked dietary components with CDI pathogenesis, suggesting that dietary modulation may be an effective strategy for prevention. Here, we show that mice fed a high-fat/low-fiber “Western-type” diet (WD) had dramatically increased mortality in a murine model of antibiotic-induced CDI compared to a low-fat/low-fiber (LF/LF) diet and standard mouse chow controls. We found that the WD had a pro- C. difficile bile acid composition that was driven in part by higher levels of primary bile acids that are produced to digest fat, and a lower level of secondary bile acids that are produced by the gut microbiome. This lack of secondary bile acids was associated with a greater disturbance to the gut microbiome with antibiotics in both the WD and LF/LF diet compared to mouse chow. Mice fed the WD also had the highest level of toxin TcdA just prior to the onset of mortality, but not of TcdB or increased inflammation. These findings indicate that dietary intervention to decrease fat may complement previously proposed dietary intervention strategies to prevent CDI in high-risk individuals.

The Application of Metabolomics to Probiotic and Prebiotic Interventions in Human Clinical Studies

There is an ever-increasing appreciation for our gut microbiota that plays a crucial role in the maintenance of health, as well as the development of disease. Probiotics are live bacteria that are consumed to increase the population of beneficial bacteria and prebiotics are dietary substrates intended to promote the propagation of beneficial bacteria. In order to optimize the use of probiotics and prebiotics, a more complete biochemical understanding of the impact that these treatments have on the community and functioning of the gut microbiota is required. Nucleic acid sequencing methods can provide highly detailed information on the composition of the microbial communities but provide less information on the actual function. As bacteria impart much of their influence on the host through the production of metabolites, there is much to be learned by the application of metabolomics. The focus of this review is on the use of metabolomics in the study of probiotic and prebiotic treatments in the context of human clinical trials. Assessment of the current state of this research will help guide the design of future studies to further elucidate the biochemical mechanism by which probiotics and prebiotics function and pave the way toward more personalized applications.

Potential Synergies of β-Hydroxybutyrate and Butyrate on the Modulation of Metabolism, Inflammation, Cognition, and General Health

The low-carbohydrate high-fat diet (LCHFD), also known as the ketogenic diet, has cycled in and out of popularity for decades as a therapeutic program to treat metabolic syndrome, weight mismanagement, and drug-resistant disorders as complex as epilepsy, cancer, dementia, and depression. Despite the benefits of this diet, health care professionals still question its safety due to the elevated serum ketones it induces and the limited dietary fiber. To compound the controversy, patient compliance with the program is poor due to the restrictive nature of the diet and symptoms related to energy deficit and gastrointestinal adversity during the introductory and energy substrate transition phase of the diet. The studies presented here demonstrate safety and efficacy of the diet including the scientific support and rationale for the administration of exogenous ketone bodies and ketone sources as a complement to the restrictive dietary protocol or as an alternative to the diet. This review also highlights the synergy provided by exogenous ketone, β-hydroxybutyrate (BHB), accompanied by the short chain fatty acid, butyrate (BA) in the context of cellular and physiological outcomes. More work is needed to unveil the molecular mechanisms by which this program provides health benefits.

Complementary Therapies in Inflammatory Bowel Diseases

Inflammatory bowel diseases (IBDs) often take a chronic debilitating course. Given the chronicity of IBD, the limitations of the available medications, their potential side effects, and the impact of the disease on patients' quality of life, it is not surprising IBD patients are ranked among the highest users of complementary and alternative medicine (CAM). Since CAM has become very popular in real-life practice of Western Communities, caregivers must gain more knowledge about these therapies, their mechanism of action, benefits, and risks. This article reviews and discusses up-to-date scientific and clinical data regarding the most prevalent herbal CAM therapies.

Cardiorespiratory fitness as a predictor of intestinal microbial diversity and distinct metagenomic functions

BACKGROUND

Reduced microbial diversity in human intestines has been implicated in various conditions such as diabetes, colorectal cancer, and inflammatory bowel disease. The role of physical fitness in the context of human intestinal microbiota is currently not known. We used high-throughput sequencing to analyze fecal microbiota of 39 healthy participants with similar age, BMI, and diets but with varying cardiorespiratory fitness levels. Fecal short-chain fatty acids were analyzed using gas chromatography.

RESULTS

We showed that peak oxygen uptake (VO2peak), the gold standard measure of cardiorespiratory fitness, can account for more than 20 % of the variation in taxonomic richness, after accounting for all other factors, including diet. While VO2peak did not explain variation in beta diversity, it did play a significant role in explaining variation in the microbiomes' predicted metagenomic functions, aligning positively with genes related to bacterial chemotaxis, motility, and fatty acid biosynthesis. These predicted functions were supported by measured increases in production of fecal butyrate, a short-chain fatty acid associated with improved gut health, amongst physically fit participants. We also identified increased abundances of key butyrate-producing taxa (Clostridiales, Roseburia, Lachnospiraceae, and Erysipelotrichaceae) amongst these individuals, which likely contributed to the observed increases in butyrate levels.

CONCLUSIONS

Results from this study show that cardiorespiratory fitness is correlated with increased microbial diversity in healthy humans and that the associated changes are anchored around a set of functional cores rather than specific taxa. The microbial profiles of fit individuals favor the production of butyrate. As increased microbiota diversity and butyrate production is associated with overall host health, our findings warrant the use of exercise prescription as an adjuvant therapy in combating dysbiosis-associated diseases.

Antibiotic Treatment Affects Intestinal Permeability and Gut Microbial Composition in Wistar Rats Dependent on Antibiotic Class

Antibiotics are frequently administered orally to treat bacterial infections not necessarily related to the gastrointestinal system. This has adverse effects on the commensal gut microbial community, as it disrupts the intricate balance between specific bacterial groups within this ecosystem, potentially leading to dysbiosis. We hypothesized that modulation of community composition and function induced by antibiotics affects intestinal integrity depending on the antibiotic administered. To address this a total of 60 Wistar rats (housed in pairs with 6 cages per group) were dosed by oral gavage with either amoxicillin (AMX), cefotaxime (CTX), vancomycin (VAN), metronidazole (MTZ), or water (CON) daily for 10-11 days. Bacterial composition, alpha diversity and caecum short chain fatty acid levels were significantly affected by AMX, CTX and VAN, and varied among antibiotic treatments. A general decrease in diversity and an increase in the relative abundance of Proteobacteria was observed for all three antibiotics. Additionally, the relative abundance of Bifidobacteriaceae was increased in the CTX group and both Lactobacillaceae and Verrucomicrobiaceae were increased in the VAN group compared to the CON group. No changes in microbiota composition or function were observed following MTZ treatment. Intestinal permeability to 4 kDa FITC-dextran decreased after CTX and VAN treatment and increased following MTZ treatment. Plasma haptoglobin levels were increased by both AMX and CTX but no changes in expression of host tight junction genes were found in any treatment group. A strong correlation between the level of caecal succinate, the relative abundance of Clostridiaceae 1 family in the caecum, and the level of acute phase protein haptoglobin in blood plasma was observed. In conclusion, antibiotic-induced changes in microbiota may be linked to alterations in intestinal permeability, although the specific interactions remain to be elucidated as changes in permeability did not always result from major changes in microbiota and vice versa.

Plant-derived polysaccharide supplements inhibit dextran sulfate sodium-induced colitis in the rat

Several plant-derived polysaccharides have been shown to have anti-inflammatory activity in animal models. Ambrotose complex and Advanced Ambrotose are dietary supplements that include aloe vera gel, arabinogalactan, fucoidan, and rice starch, all of which have shown such activity. This study was designed to evaluate these formulations against dextran sulfate sodium (DSS)-induced colitis in rats and to confirm their short-term safety after 14 days of daily dosing. Rats were dosed daily orally with vehicle, Ambrotose or Advanced Ambrotose. On day six groups of rats received tap water or 5% Dextran Sulfate sodium. Ambrotose and Advanced Ambrotose significantly lowered the disease scores and partially prevented the shortening of colon length. An increase in monocyte count was induced by dextran sulfate sodium and inhibited by Ambrotose and Advanced Ambrotose. There were no observable adverse effects after 14-day daily doses. The mechanism of action of the formulations against DSS-induced colitis may be related to its effect on monocyte count.

Supplementation with galactooligosaccharides and inulin increases bacterial translocation in artificially reared newborn rats

Supplementation of formulas with prebiotics enhances the growth of lactate producing bacteria, and fecal lactate, and acetate levels in infants. High concentrations of organic acids in intestinal lumen have, however, been shown to impair the intestinal barrier function. To determine whether stimulating the colonic microbiotal metabolism with prebiotics would impair the neonatal intestinal barrier function, artificially reared rats were fed milk formula with or without a mixture of galactooligosaccharides/inulin (GOS/Inulin, 88/12; 5.6 g/L) from the 7th d of life (d7) until weaning (d20). At d18, GOS/inulin supplementation had increased the concentrations of acetate and lactate in colonic lumen. Although neither ileum-associated microbiota nor colonic permeability (assessed in Ussing chambers), nor the expression of tight junction claudin-2 and claudin-3 mRNA were altered, GOS/inulin supplementation was associated with increased bacterial translocation (BT) toward spleen. None of these effects persisted at d40. We conclude that GOS/inulin supplementation may increase BT in an immature gut. The balance between the potential infectious risk of BT vs. its putative beneficial effect on the maturation of neonatal immune system clearly warrants further study.

Necrotizing enterocolitis: A multifactorial disease with no cure

Necrotizing enterocolitis is an inflammatory bowel disease of neonates with significant morbidity and mortality in preterm infants. Due to the multifactorial nature of the disease and limitations in disease models, early diagnosis remains challenging and the pathogenesis elusive. Although preterm birth, hypoxic-ischemic events, formula feeding, and abnormal bacteria colonization are established risk factors, the role of genetics and vasoactive/inflammatory mediators is unclear. Consequently, treatments do not target the specific underlying disease processes and are symptomatic and surgically invasive. Breast-feeding is the most effective preventative measure. Recent advances in the prevention of necrotizing enterocolitis have focused on bioactive nutrients and trophic factors in human milk. Development of new disease models including the aspect of prematurity that consistently predisposes neonates to the disease with multiple risk factors will improve our understanding of the pathogenesis and lead to discovery of innovative therapeutics.

LKM512 yogurt consumption improves the intestinal environment and induces the T-helper type 1 cytokine in adult patients with intractable atopic dermatitis

BACKGROUND

In atopic dermatitis (AD) patients, the intestinal mucosal barrier function is weakened, permiting frequent invasion by antigens. Polyamines and short-chain fatty acids (SCFA) produced by intestinal bacteria are involved in the promotion of intestinal mucosal barrier functions.

AIM

Our aim was to investigate the effect of pro-biotic yogurt containing Bifidobacterium animalis subsp. lactis LKM512 (LKM512 yogurt) on subjective symptoms, intestinal microbiota, intestinal bacterial metabolites (polyamines and SCFA), and T-helper type 1 (Th1)/Th2 balance in intractable AD patients.

METHODS

In a double-blind, placebo-controlled, crossover study, LKM512 yogurt was given for 4 weeks to 10 adult AD patients who were diagnosed with moderate AD (four males and six females; average age, 22.1 years). The subjective symptoms were recorded after each intervention. The dynamics of fecal microbiota were analysed by the terminal-restriction fragment length polymorphism method. The effects of LKM512 yogurt on fecal polyamines, SCFA, and serum cytokines were evaluated.

RESULTS

Scores of itch and burning tended to improve to a greater extent by LKM512 yogurt consumption than by placebo consumption. LKM512 yogurt (P<0.005) and placebo consumption (P<0.05) significantly increased the serum IFN-gamma concentration by six- and threefold, respectively. Fecal microbiota was altered dynamically by LKM512 yogurt consumption, in particular, the bacterial species and phylotypes of Bifidobacterium, Clostridium cluster IV and subcluster XIVa were increased in number. In addition, fecal spermidine concentration was significantly (P<0.05) increased, while fecal butyrate also tended to be increased by LKM512 yogurt consumption.

CONCLUSION

We conclude that LKM512 yogurt consumption may be effective against intractable adult-type AD and this effect depends on the recovery of the intestinal mucosal barrier function and the induction of the Th1-type cytokine by polyamines and SCFA, particularly, butyrate, produced by the altered intestinal microbiota.

Therapeutic approaches targeting intestinal microflora in inflammatory bowel disease

Inflammatory bowel diseases, ulcerative colitis, and Crohn’s disease, are chronic intestinal disorders of unknown etiology in which in genetically susceptible individuals, the mucosal immune system shows an aberrant response towards commensal bacteria. The gastrointestinal tract has developed ingenious mechanisms to coexist with its autologous microflora, but rapidly responds to invading pathogens and then returns to homeostasis with its commensal bacteria after the pathogenic infection is cleared. In case of disruption of this tightly-regulated homeostasis, chronic intestinal inflammation may be induced. Previous studies showed that some commensal bacteria are detrimental while others have either no influence or have a protective action. In addition, each host has a genetically determined response to detrimental and protective bacterial species. These suggest that therapeutic manipulation of imbalance of microflora can influence health and disease. This review focuses on new insights into the role of commensal bacteria in gut health and disease, and presents recent findings in innate and adaptive immune interactions. Therapeutic approaches to modulate balance of intestinal microflora and their potential mechanisms of action are also discussed.

Short-chain fatty acids modulate gene expression for vascular endothelial cell adhesion molecules

OBJECTIVE

Leukocyte infiltration into the intestinal wall is central to the pathogenesis of tissue injury that occurs in patients with a variety of inflammatory bowel diseases. Migration of leukocytes from the intestinal circulation into bowel tissues is mediated by chemotactic substances and adhesion molecules (i.e., intercellular adhesion molecule-1 [ICAM-1] and E-selectin) on the surface of endothelial cells lining blood vessels. Short-chain fatty acids (SCFAs) derived from dietary fiber decrease inflammatory responses in colon cells. However, the effect of SCFAs on vascular adhesion molecules is unknown. We investigated the effects of SCFAs on vascular endothelial cell adhesion molecule expression.

METHODS

We assessed the effect of physiologically relevant concentrations of butyrate on expression of ICAM-1 protein and mRNA in cultures of human umbilical vein endothelial cells. We also assessed the effect of butyrate on levels of HLA-DR, E-selectin, vascular cell adhesion molecule-1, and endoglin. In additional experiments, we evaluated the effect of butyrate on ICAM-1 mRNA stability and the effect of valerate, isobutyrate, and propionate on ICAM-1 expression. The effect of butyrate on ICAM-1 expression was compared with that of trichostatin A, a specific inhibitor of histone deacetylase. Data were evaluated with Student's t tests or Tukey's multiple comparison tests, with P < 0.05 considered statistically significant.

RESULTS

Butyrate concentrations of 2.5 to 5 mM significantly increased endothelial expressions of ICAM-1 protein and mRNA. The effect of butyrate (5 mM) on ICAM-1 expression was time dependent, with significant increases in levels occurring after 16 h of incubation. Butyrate (5 mM) also increased expression of E-selectin but not of HLA-DR, vascular cell adhesion molecule-1, or endoglin. Isobutyrate had little effect on ICAM-1 expression, whereas valerate and propionate significantly increased expression of ICAM-1 but were weaker stimulants compared with butyrate. Butyrate (5 mM) did not alter stability of ICAM-1 mRNA. The effect of butyrate (5 mM) was comparable to that of trichostatin A. The stimulatory effect of butyrate on ICAM-1 expression was reversed after 48 h of butyrate withdrawal.

CONCLUSIONS

Butyrate increases vascular endothelial expressions of ICAM-1 and E-selectin. We speculate that butyrate-induced effects on vascular adhesion molecules modulate gut inflammation. The role of SCFAs and fiber in the pathogenesis and modulation of gut inflammation in vivo requires further study.

HDAC inhibition prevents NF-kappa B activation by suppressing proteasome activity: down-regulation of proteasome subunit expression stabilizes I kappa B alpha

The short chain fatty acid (SCFA) butyrate (BA) and other histone deacetylase (HDAC) inhibitors can rapidly induce cell cycle arrest and differentation of colon cancer cell lines. We found that butyrate and the specific HDAC inhibitor trichostatin A (TSA) can reprogram the NF-(kappa)B response in colon cancer cells. Specifically, TNF-alpha activation is suppressed in butyrate-differentiated cells, whereas IL-1beta activation is largely unaffected. To gain insight into the relationship between butyrate-induced differentiation and NF-(kappa)B regulation, we determined the impact of butyrate on proteasome activity and subunit expression. Interestingly, butyrate and TSA reduced the cellular proteasome activity in colon cancer cell lines. The drop in proteasome activity results from the reduced expression of the catalytic beta-type subunits of the proteasome at both the protein and mRNA level. The selective impact of HDAC inhibitors on TNF-alpha-induced NF-(kappa)B activation appears to relate to the fact that the TNF-alpha-induced activation of NF-(kappa)B is mediated by the proteasome, whereas NF-kappaB activation by IL-1beta is largely proteasome-independent. These findings indicate that cellular differentation status and/or proliferative capacity can significantly impact proteasome activity and selectively alter NF-(kappa)B responses in colon cancer cells. This information may be useful for the further development and targeting of HDAC inhibitors as anti-neoplastic and anti-inflammatory agents.

Luminal bacterial flora determines physiological expression of intestinal epithelial cytoprotective heat shock proteins 25 and 72

Heat shock proteins (HSP) 25 and 72 are expressed normally by surface colonocytes but not by small intestinal enterocytes. We hypothesized that luminal commensal microflora maintain the observed colonocyte HSP expression. The ability of the small intestine to respond to bacteria and their products and modulate HSPs has not been determined. The effects of luminal bacterial flora in surgically created midjejunal self-filling (SFL) vs. self-emptying (SEL) small-bowel blind loops on epithelial HSP expression were studied. HSP25 and HSP72 expression were assessed by immunoblot and immunohistochemistry. SFL were chronically colonized, whereas SEL contained levels of bacteria normal for the proximal small intestine. SFL creation significantly increased HSP25 and HSP72 expression relative to corresponding sections from SEL. Metronidazole treatment, which primarily affects anaerobic bacteria as well as a diet lacking fermentable fiber, significantly decreased SFL HSP expression. Small bowel incubation with butyrate ex vivo induced a sustained and significant upregulation of HSP25 and altered HSP72 expression, confirming the role of short-chain fatty acids. To determine whether HSPs induction altered responses to an injury, effects of the oxidant, monochloramine, on epithelial resistance and short-circuit current (I(sc)) responses to carbachol and glucose were compared. Increased SFL HSP expression was associated with protection against oxidant-induced decreases in transmural resistance and I(sc) responses to glucose, but not secretory responses to carbachol. In conclusion, luminal microflora and their metabolic byproducts direct expression of HSPs in gut epithelial cells, an effect that contributes to preservation of epithelial cell viability under conditions of stress.

Gene expression profile of butyrate-inhibited vascular smooth muscle cell proliferation

Excessive proliferation of vascular smooth muscle cells (VSMCs) is a critical element in the development of several vascular pathologies, particularly in atherosclerosis and in restenosis due to angioplasty. We have shown that butyrate, a powerful antiproliferative agent, a strong promoter of cell differentiation and an inducer of apoptosis inhibits VSMC proliferation at physiological concentrations with no cytotoxicity. In the present study, we have used cDNA array technology to unravel the molecular basis of the antiproliferative effect of butyrate on VSMCs. To assess the involvement of gene expression in butyrate-inhibited VSMC proliferation, proliferating VSMCs were exposed to 5 mmol/l butyrate 1 through 5 days after plating. Expression profiles of 1.176 genes representing different functional classes in untreated control and butyrate treated VSMCs were compared. A total of 111 genes exhibiting moderate (2.0-5.0 fold) to strong (> 5.0 fold) differential expression were identified. Analysis of these genes indicates that butyrate treatment mainly alters the expression of four different functional classes of genes, which include: 43 genes implicated in cell growth and differentiation, 13 genes related to stress response, 11 genes associated with vascular function and 8 genes normally present in neuronal cells. Examination of differentially expressed cell growth and differentiation related genes indicate that butyrate-inhibited VSMC proliferation appears to involve down-regulation of genes that encode several positive regulators of cell growth and up-regulation of some negative regulators of growth or differentiation inducers. Some of the down-regulated genes include proliferating cell nuclear antigen (PCNA), retinoblastoma susceptibility related protein p130 (pRb), cell division control protein 2 homolog (cdc2), cyclin B1, cell division control protein 20 homolog (p55cdc), high mobility group (HMG) 1 and 2 and several others. Whereas the up-regulated genes include cyclin D1, p21WAF1, p141NK4B/p15INK5B, Clusterin, inhibitor of DNA binding 1 (ID1) and others. On the other hand, butyrate-responsive stress-related genes include some of the members of heat shock protein (HSP), glutathione-s-transferase (GST), glutathione peroxidase (GSH-PXs) and cytochrome P450 (CYP) families. Additionally, several genes related to vascular and neuronal function are also responsive to butyrate treatment. Although involvement of genes that encode stress response, vascular and neuronal functional proteins in cell proliferation is not clear, cDNA expression array data appear to suggest that they may play a role in the regulation of cell proliferation. However, cDNA expression profiles indicate that butyrate-inhibited VSMC proliferation involves combined action of a proportionally large number of both positive and negative regulators of growth, which ultimately causes growth arrest of VSMCs. Furthermore, these butyrate-induced differential gene expression changes are not only consistent with the antiproliferative effect of butyrate but are also in agreement with the roles that these gene products play in cell proliferation.

Restoration of the integrity of rat caeco-colonic mucosa by resistant starch, but not by fructo-oligosaccharides, in dextran sulfate sodium-induced experimental colitis

Butyrate is recognised as efficient in healing colonic inflammation, but cannot be used as a long-term treatment. Dietary fibre that produces a high-butyrate level when fermented represents a promising alternative. We hypothesised that different types of dietary fibre do not have the same efficiency of healing and that this could be correlated to their fermentation characteristics. We compared short-chain fructo-oligosaccharides (FOS) and type 3 resistant starch (RS) in a previously described dextran sulfate sodium (DSS)-induced colitis model. Seventy-two Sprague-Dawley rats received water (control rats) or DSS (50 g DSS/l for 7 d then 30 g DSS/l for 7 (day 7) or 14 (day 14) d). The rats were fed a basal diet (BD), or a FOS or RS diet creating six groups: BD-control, BD-DSS, FOS-control, FOS-DSS, RS-control and RS-DSS. Caeco-colonic inflammatory injuries were assessed macroscopically and histologically. Short-chain fatty acids (SCFA) were quantified in caeco-colon, portal vein and abdominal aorta. At days 7 and 14, caecal and distal macroscopic and histological observations were improved in RS-DSS compared with BD-DSS and also with FOS-DSS rats. Caeco-colonic SCFA were reduced in FOS-DSS and RS-DSS groups compared with healthy controls. The amount of butyrate was higher in the caecum of the RS-DSS rats than in the BD-DSS and FOS-DSS rats, whereas distal butyrate was higher in FOS-DSS rats. Partially explained by higher luminal levels of SCFA, especially butyrate, the healing effect of RS confirms the involvement of some types of dietary fibre in inflammatory bowel disease. Moreover, the ineffectiveness of FOS underlines the importance of the type of dietary substrate.

A new prebiotic from germinated barley for nutraceutical treatment of ulcerative colitis

A germinated barley foodstuff (GBF) containing glutamine-rich protein and hemicellulose-rich fiber was made from brewer's spent grain, by physical isolation. Our previous studies demonstrated that GBF supported maintenance of epithelial cell populations, facilitated epithelial repair, and suppressed epithelial nuclear factor kappaB-DNA-binding activity through generating increased short-chain fatty acid (especially butyrate) production by luminal microflora, which includes Bifidobacterium and Eubacterium, thereby preventing experimental colonic injury. The fiber fraction also modulates stool water content because of its high water-holding capacity. The patients with mild to moderate active ulcerative colitis who had been unresponsive to or intolerant of standard treatment received 20-30 g GBF, feeding daily in a non-randomized, open-label fashion. At 4 weeks, this treatment resulted in a significant clinical and endoscopic improvement. The improvement was associated with an increase in stool butyrate concentrations. These results indicate that GBF feeding is a potentially new, attractive prebiotic treatment in patients with ulcerative colitis. The potency of GBF on modulating microflora, as well as the high water-holding capacity, may play an important role in treatment and prolongation of remission in ulcerative colitis.

Butyrate suppression of colonocyte NF-kappa B activation and cellular proteasome activity

Butyrate is derived from the microbial metabolism of dietary fiber in the colon where it plays an important role in linking colonocyte turnover and differentiation to luminal content. In addition, butyrate appears to have both anti-inflammatory and cancer chemopreventive activities. Using confocal microscopy and cell fractionation studies, butyrate pretreatment of a human colon cell line (HT-29 cells) inhibited the tumor necrosis factor-alpha (TNF-alpha)-induced nuclear translocation of the proinflammatory transcription factor NF-kappaB. Butyrate inhibited NF-kappaB DNA binding within 30 min of TNF-alpha stimulation, consistent with an inhibition of nuclear translocation. IkappaB.NF-kappaB complexes extracted from butyrate-treated cells were relatively resistant to in vitro dissociation by deoxycholate, suggesting a change in cellular IkappaB composition. Butyrate treatment increased p100 expression, an IkappaB that was not degraded upon TNF-alpha treatment. Butyrate also reduced the extent of TNF-alpha-induced IkappaB-alpha degradation and enhanced the presence of ubiquitin-conjugated IkappaB-alpha. The suppression of IkappaB-alpha degradation corresponded with a reduction in cellular proteasome activity as determined by in vitro proteasome assays and the increased presence of ubiquitin-conjugated proteins. The butyrate suppression of IkappaB-alpha degradation and proteasome activity may derive from its ability to inhibit histone deacetylases since the specific deacetylase inhibitor trichostatin A had similar effects. These results suggest a potential mechanism for the anti-inflammatory activity of butyrate and demonstrate the interplay between short chain fatty acids and cellular proteasome activity.

Dietary fiber fraction of germinated barley foodstuff attenuated mucosal damage and diarrhea, and accelerated the repair of the colonic mucosa in an experimental colitis

BACKGROUND AND AIMS

Germinated barley foodstuff (GBF) contains protein and insoluble dietary fiber. We have previously shown in ulcerative colitis patients and a colitis model that GBF feeding attenuates mucosal damage by increasing luminal butyrate levels. However, the detailed mechanism remains unclear because of its heterogeneous nature. The present study was carried out to: (i) evaluate the active ingredient in GBF; and (ii) examine its effect on the repair process in colonic inflammation by using a dextran sulfate sodium (DSS) colitis model.

METHODS

Colitis was induced by feeding a diet containing 0.5-3.5% DSS to male Sprague-Dawley rats. (i) Active ingredient: GBF was fractionated enzymatically into fiber- and protein-rich fractions. Each fraction was administered to DSS-colitis rats. Clinical signs, cecal short chain fatty acid concentrations and serum alpha1-acid glycoprotein (AAG) levels were determined. (ii) Effect on mucosal repair: GBF with or without salazosulfapyridine (SASP), or SASP alone was administered to rats after the onset of colitis. Seven days after initial treatment, the number of epithelial cells in HE sections was evaluated morphologically in a blind fashion and serum AAG was determined.

RESULTS

(i) Germinate barley foodstuff and GBF-fiber significantly attenuated the clinical signs of colitis and decreased serum AAG levels, with a significant increase in cecal butyrate production, while GBF-protein did not. (ii) Treatment with GBF alone and GBF plus SASP significantly accelerated colonic epithelial repair and improved clinical signs.

CONCLUSIONS

These findings suggest that the fiber fraction of GBF may effectively enhance luminal butyrate production, and thereby accelerate colonic epithelial repair in colitis.

The dietary combination of germinated barley foodstuff plus Clostridium butyricum suppresses the dextran sulfate sodium-induced experimental colitis in rats

BACKGROUND

Recent studies have suggested that dietary fiber exerts a therapeutic effect on IBD patients. The aim of this study was to evaluate the effects of a dietary combination of germinated barley foodstuff (GBF), derived from the aleurone and scutellum fraction of germinated barley, plus Clostridium butyricum against dextran sulfate sodium (DSS)-induced experimental colitis in rats.

METHODS

Sprague-Dawley rats were fed a 3% DSS diet containing GBF only, GBF plus C. butyricum, cellulose only (control) or cellulose plus C. butyricum for 8 days. The mucosal damage (macroscopic and microscopic inflammation) and fecal short-chain fatty acid (SCFA) levels were then determined.

RESULTS

The combination of GBF plus C. butyricum most effectively prevented bloody diarrhea and mucosal damage. The GBF-only diet also showed some preventive effects. With respect to fecal SCFAs, the combination of GBF plus C. butyricum most effectively increased the fecal SCFA level.

CONCLUSION

The dietary combination of GBF plus C. butyricum most effectively suppressed DSS-induced experimental colitis in rats. These effects may be closely associated with its high activity to increase SCFA levels in the gut lumen. The potential clinical efficacy of GBF in IBD patients is also discussed.

Germinated barley foodstuffs attenuate colonic mucosal damage and mucosal nuclear factor kappa B activity in a spontaneous colitis model

BACKGROUND

Germinated barley foodstuffs (GBF), which are derived from brewer's spent grain and are a highly safe food substance, increased butyrate production in the lower intestine and prevented mucosal damage and bloody diarrhoea in an acute experimental colitis model. As human histocompatibility leucocyte antigen (HLA)-B27 transgenic rats develop spontaneous and chronic intestinal inflammation resembling ulcerative colitis, we investigated the mechanisms underlying the preventive effects of GBF against a spontaneous and chronic colitis model. Specifically, the production of bacterial butyrate and the regulation of proinflammatory cytokine production were examined.

METHODS

A GBF diet and a cellulose (CE) diet were fed to HLA-B27 transgenic rats for 13 weeks. The presence of faecal occult blood, colonic mucosal protein, DNA and RNA content, colonic myeloperoxidase activity, nuclear factor kappa B (NFkappaB) DNA binding activity, the depth of the crypts and serum inflammatory parameters were then evaluated. Butyrate production in the caecal contents was also determined.

RESULTS

Feeding GBF significantly increased bacterial butyrate production and simultaneously attenuated the presence of faecal occult blood and colonic mucosal hyperplasia. Colonic mucosal NFkappaB-DNA binding activity and the production of interleukin-8 were also suppressed by the butyrate produced from GBF.

CONCLUSIONS

Germinated barley foodstuffs feeding promotes bacterial butyrate production and attenuated inflammation in both spontaneous and chronic colitis in HLA-B27 transgenic rats.