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

Probiotic potential of Lacticaseibacillus rhamnosus VHProbi M15 on sucralfate-induced constipation in mice

The main objective of this study was to investigate the potential probiotic properties of Lacticaseibacillus rhamnosus VHProbi®M15 (M15). This study examined the effects of M15 on sucralfate-induced constipation in a mouse model. The BALB/c mice were randomly divided into four groups: the normal group (NOR) was without any treatment, while the constipation (CON), phenolphthalein (PHE), and probiotic (PRO) treatment groups were fed with sucralfate until the appearance of constipation symptoms. Afterward, the NOR and CON groups were given 1 ml saline orally every day until the end of the experiment; the PHE and PRO groups were given phenolphthalein or M15 suspension in 1 ml orally, respectively. Compared with the CON group, the fecal water content and intestinal peristalsis improved in the PRO group. Here, intake of M15 effectively attenuated sucralfate-induced constipation, recuperated colonic epithelial integrity, and increased serum levels of gastrointestinal excitatory neurotransmitters (motilin, gastrin, substance P). Analysis of the intestinal microbiota of mice by 16S rRNA metagenomic revealed an increase in the relative abundance of Bacteroides and a decrease in Sclerotinia, Verrucosa and Proteus in the PRO group. Compared with the CON group, the constipation-induced intestinal microecological changes were partially recovered in the PHE and PRO groups. These results demonstrate that M15 enhanced gastrointestinal transit and alleviated in mice with sucralfate-induced constipation.

Native and Engineered Probiotics: Promising Agents against Related Systemic and Intestinal Diseases

Intestinal homeostasis is a dynamic balance involving the interaction between the host intestinal mucosa, immune barrier, intestinal microecology, nutrients, and metabolites. Once homeostasis is out of balance, it will increase the risk of intestinal diseases and is also closely associated with some systemic diseases. Probiotics (Escherichia coli Nissle 1917, Akkermansia muciniphila, Clostridium butyricum, lactic acid bacteria and Bifidobacterium spp.), maintaining the gut homeostasis through direct interaction with the intestine, can also exist as a specific agent to prevent, alleviate, or cure intestinal-related diseases. With genetic engineering technology advancing, probiotics can also show targeted therapeutic properties. The aims of this review are to summarize the roles of potential native and engineered probiotics in oncology, inflammatory bowel disease, and obesity, discussing the therapeutic applications of these probiotics.

Mechanistic basis and preliminary practice of butyric acid and butyrate sodium to mitigate gut inflammatory diseases: a comprehensive review

A key event featured in the early stage of chronic gut inflammatory diseases is the disordered recruitment and excess accumulation of immune cells in the gut lamina propria. This process is followed by the over-secretion of pro-inflammatory factors and the prolonged overactive inflammatory responses. Growing evidence has suggested that gut inflammatory diseases may be mitigated by butyric acid (BA) or butyrate sodium (NaB). Laboratory studies show that BA and NaB can enhance gut innate immune function through G-protein-mediated signaling pathways while mitigating the overactive inflammatory responses by inhibiting histone deacetylase. The regulatory effects may occur in both epithelial enterocytes and the immune cells in the lamina propria. Prior to further clinical trials, comprehensive literature reviews and rigid examination concerning the underlying mechanism are necessary. To this end, we collected and reviewed 197 published reports regarding the mechanisms, bioactivities, and clinical effects of BA and NaB to modulate gut inflammatory diseases. Our review found insufficient evidence to guarantee the safety of clinical practice of BA and NaB, either by anal enema or oral administration of capsule or tablet. The safety of clinical use of BA and NaB should be further evaluated. Alternatively, dietary patterns rich in "fruits, vegetables and beans" may be an effective and safe approach to prevent gut inflammatory disease, which elevates gut microbiota-dependent production of BA. Our review provides a comprehensive reference to future clinical trials of BA and NaB to treat gut inflammatory diseases.

Barley-based probiotic food mixture: health effects and future prospects

Consumers around the globe are increasingly aware of the relation between nutrition and health. In this sense, food products that can improve gastrointestinal health such as probiotics, prebiotics and synbiotics are the most important segment within functional foods. Cereals are the potential substrates for probiotic products as they contain nutrients easily assimilated by probiotics and serve as the transporters of Lactobacilli through the severe conditions of gastrointestinal tract. Barley is one of the important substrates for the probiotic formulation because of its high phenolic compounds, β-glucans and tocols. The purpose of this review is to examine recent information regarding barley-based probiotic foods with a specific focus on the potential benefits of barley as a substrate for probiotic microorganisms in the development of dairy and nondairy based food products, and to study the effects of food matrices containing barley β-glucans on the growth and features of Lactobacillus strains after fermentation.

The effects of resistant starches on inflammatory bowel disease in preclinical and clinical settings: a systematic review and meta-analysis

Background

Inflammatory bowel disease (IBD) is a debilitating chronic disease with limited treatment options. Resistant starches may represent a novel treatment for IBD. However, its efficacy and safety remain unclear. Our objective was to perform a systematic review to summarize the preclinical and clinical effects of resistant starch, which may help guide future studies.

Methods

Medline, EMBASE, and the Cochrane Central Register were searched. Included studies investigated the use of resistant starch therapy in in vivo animal models of IBD or human patients with IBD. Articles were screened, and data extracted, independently and in duplicate. The primary outcomes were clinical remission (clinical) and bowel mucosal damage (preclinical).

Results

21 preclinical (n = 989 animals) and seven clinical (n = 164 patients) studies met eligibility. Preclinically, resistant starch was associated with a significant reduction in bowel mucosal damage compared to placebo (standardized mean difference − 1.83, 95% CI − 2.45 to − 1.20). Clinically, five studies reported data on clinical remission but clinical and methodological heterogeneity precluded pooling. In all five, a positive effect was seen in patients who consumed resistant starch supplemented diets. The majority of studies in both the preclinical and clinical settings were at a high or unclear risk of bias due to poor methodological reporting.

Conclusions

Our review demonstrates that resistant starch is associated with reduced histology damage in animal studies, and improvements in clinical remission in IBD patients. These results need to be tempered by the risk of bias of included studies. Rigorously designed preclinical and clinical studies are warranted.

Trial registration

The review protocols were registered on PROSPERO (preclinical: CRD42019130896; clinical: CRD42019129513).

Nondigestible carbohydrates, butyrate, and butyrate-producing bacteria

Nondigestible carbohydrates (NDCs) are fermentation substrates in the colon after escaping digestion in the upper gastrointestinal tract. Among NDCs, resistant starch is not hydrolyzed by pancreatic amylases but can be degraded by enzymes produced by large intestinal bacteria, including clostridia, bacteroides, and bifidobacteria. Nonstarch polysaccharides, such as pectin, guar gum, alginate, arabinoxylan, and inulin fructans, and nondigestible oligosaccharides and their derivatives, can also be fermented by beneficial bacteria in the large intestine. Butyrate is one of the most important metabolites produced through gastrointestinal microbial fermentation and functions as a major energy source for colonocytes by directly affecting the growth and differentiation of colonocytes. Moreover, butyrate has various physiological effects, including enhancement of intestinal barrier function and mucosal immunity. In this review, several representative NDCs are introduced, and their chemical components, structures, and physiological functions, including promotion of the proliferation of butyrate-producing bacteria and enhancement of butyrate production, are discussed. We also describe the strategies for achieving directional accumulation of colonic butyrate based on endogenous generation mechanisms.

Effect of Dietary Fiber and Metabolites on Mast Cell Activation and Mast Cell-Associated Diseases

Many mast cell-associated diseases, including allergies and asthma, have seen a strong increase in prevalence during the past decades, especially in Western(ized) countries. It has been suggested that a Western diet may contribute to the prevalence and manifestation of allergies and asthma through reduced intake of dietary fiber and the subsequent production of their metabolites. Indeed, dietary fiber and its metabolites have been shown to positively influence the development of immune disorders via changes in microbiota composition and the regulation of B- and T-cell activation. However, the effects of these dietary components on the activation of mast cells, key effector cells of the inflammatory response in allergies and asthma, remain poorly characterized. Due to their location in the gut and vascularized tissues, mast cells are exposed to high concentrations of dietary fiber and/or its metabolites. Here, we provide a focused overview of current findings regarding the direct effects of dietary fiber and its various metabolites on the regulation of mast cell activity and the pathophysiology of mast cell-associated diseases.

Prebiotics and synbiotics in ulcerative colitis

BACKGROUND

Ulcerative colitis (UC) is a chronic inflammatory disease of the colon with unclear pathogenesis. A dysbiotic intestinal microbiota is regarded as a key component in the disease process and there has been significant interest in developing new treatments which target the microbiota.

AIM

To give an overview of the studies to date investigating prebiotics and synbiotics for the treatment of UC.

METHODS

A literature search of PubMed and related search engines was carried out using the terms "ulcerative colitis" in combination with "prebiotic", "synbiotic" or "dietary fibre".

RESULTS

In total 17 studies on humans examining the effect of prebiotics in UC were found. Five major groups could be distinguished. Fructo-oligosaccharides were tried in six studies (mean 35 patients included, range 9-121). One study found a clinical response while two demonstrated indirect evidence of an effect. Germinated barley foodstuff was used in 8 studies (mean 38 patients, range 10-63). One study found an endoscopic response, while four noted a clinical response and two some indirect effects. Galacto-oligosaccharides, lactulose and resveratrol were used in one study each (mean 48 patients, range 41-52). One study found an endoscopic response and one a clinical response.

CONCLUSION

There is yet inadequate evidence - especially in humans - to support any particular prebiotic in the clinical management of UC. However, due to the bulk of evidence supporting the effect of the microbiota on colonic inflammation, there is enough potential to justify further high-quality clinical trials investigating this subject.

Prebiotics: A Potential Treatment Strategy for the Chemotherapy-damaged Gut?

Mucositis, characterized by ulcerative lesions along the alimentary tract, is a common consequence of many chemotherapy regimens. Chemotherapy negatively disrupts the intestinal microbiota, resulting in increased numbers of potentially pathogenic bacteria, such as Clostridia and Enterobacteriaceae, and decreased numbers of "beneficial" bacteria, such as Lactobacilli and Bifidobacteria. Agents capable of restoring homeostasis in the bowel microbiota could, therefore, be applicable to mucositis. Prebiotics are indigestible compounds, commonly oligosaccharides, that seek to reverse chemotherapy-induced intestinal dysbiosis through selective colonization of the intestinal microbiota by probiotic bacteria. In addition, evidence is emerging that certain prebiotics contribute to nutrient digestibility and absorption, modulate intestinal barrier function through effects on mucin expression, and also modify mucosal immune responses, possibly via inflammasome-mediated processes. This review examines the known mechanisms of prebiotic action, and explores their potential for reducing the severity of chemotherapy-induced mucositis in the intestine.

Intestinal health functions of colonic microbial metabolites: a review

This review tries to find a scientific answer on the following two questions: (1) to what extent do we understand the specific role of colonic microbial metabolites, especially short-chain fatty acids (SCFA), in maintaining the health status and prevention of diseases of the colon and the host; (2) to what extent can we influence or even control the formation of colonic microbial metabolites which are beneficial for the health status. The review focuses on the following topics: energy source, intestinal motility, defence barrier, oxidative stress with special attention for antiinflammatory and anti-carcinogen functions, and satiety. Also the risk of overproduction of SCFA is discussed. Reviewing the literature as present today, it can be concluded that physiological levels of SCFA are vital for the health and well-being of the host and that the presence of carbohydrates (dietary fibre, prebiotics) is essential to favour the metabolic activity in the direction of carbohydrate fermentation. For optimal motor activity of the ileum and colon, to regulate the physiological intestinal mobility, steadily fermentable dietary fibres or prebiotics are crucial. The formation of SCFA, especially propionate and butyrate, up to high physiological levels in the colon, much likely also contributes to the defence mechanisms of the intestinal wall. No final answer can be given yet about the role of SCFA in anti-inflammation and anti-carcinogenicity, but recently published research shows possible mechanisms in this field. The intake of prebiotics or specific dietary fibres promotes the formation of SCFA within the physiological range, and more or less specifically increases the levels of propionate and butyrate. In this way, they provide benefit to the host, especially the natural regulation of the digestive system.

The effect of dietary prebiotics and probiotics on body weight, large intestine indices, and fecal bile acid profile in wild type and IL10-/- mice

Previous studies have suggested roles of probiotics and prebiotics on body weight management and intestinal function. Here, the effects of a dietary prebiotic, inulin (50 mg/g diet), and probiotic, Bfidobacterium animalis subsp. lactis (Bb12) (final dose verified at 10⁵ colony forming unit (cfu)/g diet, comparable to human consumption), were determined separately and in combination in mice using cellulose-based AIN-93G diets under conditions allowed for the growth of commensal bacteria. Continuous consumption of Bb12 and/or inulin did not affect food intake or body, liver, and spleen weights of young and adult mice. Fecal bile acid profiles were determined by nanoESI-MS/MS tandem mass spectrometry. In the presence of inulin, more bacterial deconjugation of taurine from primary bile acids was observed along with an increased cecal weight. Consumption of inulin in the absence or presence of Bb12 also increased the villus cell height in the proximal colon along with a trend of higher bile acid sulfation by intestinal cells. Feeding Bb12 alone at the physiological dose did not affect bile acid deconjugation and had little effect on other intestinal indices. Although interleukin (IL)10-null mice are susceptible to enterocolitis, they maintained the same body weight as the wild type mice under our specific pathogen-free housing condition and showed no signs of inflammation. Nevertheless, they had smaller cecum suggesting a mildly compromised intestinal development even before the disease manifestation. Our results are consistent with the notion that dietary factors such as prebiotics play important roles in the growth of intestinal microbiota and may impact on the intestinal health. In addition, fecal bile acid profiling could potentially be a non-invasive tool in monitoring the intestinal environment.

The interplay between fiber and the intestinal microbiome in the inflammatory response

Fiber intake is critical for optimal health. This review covers the anti-inflammatory roles of fibers using results from human epidemiological observations, clinical trials, and animal studies. Fiber has body weight-related anti-inflammatory activity. With its lower energy density, a diet high in fiber has been linked to lower body weight, alleviating obesity-induced chronic inflammation evidenced by reduced amounts of inflammatory markers in human and animal studies. Body weight-unrelated anti-inflammatory activity of fiber has also been extensively studied in animal models in which the type and amount of fiber intake can be closely monitored. Fermentable fructose-, glucose-, and galactose-based fibers as well as mixed fibers have shown systemic and local intestinal anti-inflammatory activities when plasma inflammatory markers and tissue inflammation were examined. Similar anti-inflammatory activities have also been demonstrated in some human studies that controlled total fiber intake. The anti-inflammatory activities of synbiotics (probiotics plus fiber) were reviewed as well, but there was no convincing evidence indicating higher efficacy of synbiotics compared with that of fiber alone. Adverse effects have not been observed with the amount of fiber intake or supplementation used in studies, although patients with Crohn's disease may be more sensitive to inulin intake. Several possible mechanisms that may mediate the body weight-unrelated anti-inflammatory activity of fibers are discussed based on the in vitro and in vivo evidence. Fermentable fibers are known to affect the intestinal microbiome. The immunomodulatory role of the intestinal microbiome and/or microbial metabolites could contribute to the systemic and local anti-inflammatory activities of fibers.

Protective effect of Clostridium tyrobutyricum in acute dextran sodium sulphate-induced colitis: differential regulation of tumour necrosis factor-α and interleukin-18 in BALB/c and severe combined immunodeficiency mice

One of the promising approaches in the therapy of ulcerative colitis is administration of butyrate, an energy source for colonocytes, into the lumen of the colon. This study investigates the effect of butyrate producing bacterium Clostridium tyrobutyricum on dextran sodium sulphate (DSS)-induced colitis in mice. Immunocompetent BALB/c and immunodeficient severe combined immunodeficiency (SCID) mice reared in specific-pathogen-free (SPF) conditions were treated intrarectally with C. tyrobutyricum 1 week prior to the induction of DSS colitis and during oral DSS treatment. Administration of DSS without C. tyrobutyricum treatment led to an appearance of clinical symptoms - bleeding, rectal prolapses and colitis-induced increase in the antigen CD11b, a marker of infiltrating inflammatory cells in the lamina propria. The severity of colitis was similar in BALB/c and SCID mice as judged by the histological damage score and colon shortening after 7 days of DSS treatment. Both strains of mice also showed a similar reduction in tight junction (TJ) protein zonula occludens (ZO)-1 expression and of MUC-2 mucin depression. Highly elevated levels of cytokine tumour necrosis factor (TNF)-α in the colon of SCID mice and of interleukin (IL)-18 in BALB/c mice were observed. Intrarectal administration of C. tyrobutyricum prevented appearance of clinical symptoms of DSS-colitis, restored normal MUC-2 production, unaltered expression of TJ protein ZO-1 and decreased levels of TNF-α and IL-18 in the descending colon of SCID and BALB/c mice, respectively. Some of these features can be ascribed to the increased production of butyrate in the lumen of the colon and its role in protection of barrier functions and regulation of IL-18 expression.

New prebiotics from rice bran ameliorate inflammation in murine colitis models through the modulation of intestinal homeostasis and the mucosal immune system

BACKGROUND

Enzyme-treated rice fiber (ERF) is a recently developed prebiotic product made from rice bran by heat-resistant amylase, protease and hemicellulase treatment. Although the detailed mechanism of inflammatory bowel disease (IBD) is still unclear, the role of the resident luminal bacteria and its interaction on the mucosal barrier seem to be an important factor in the development of IBD and its chronicity. With the objective of manipulating the intestinal microbiota in IBD, this study was carried out to evaluate the effects of ERF on IBD with using experimental colitis models.

METHODS

Three colitis models were used and they were induced by the oral administration of dextran sodium sulfate in male Sprague-Dawley rats or BALB/c mice and transferring CD4+ CD45RB(high) T cells to female SCID mice, sequentially their CD4+ T cells were retransferred to new SCID mice. The evaluation included the measurement of body weight, spleen weight, colon length, histological examination, serum and mucosal cytokine (tumor necrosis factor-alpha (TNF-α), an interferon-gamma (IFN-γ), interleukin-12 p70 (IL-12p70), IL-1β, IL-6, IL-4) analysis, mucosal serotonin (5HT), and organic acid production and a microbiota analysis of the cecal contents. The characteristics of T cell surface markers including CD4, CD69, CD45RB of spleen and mesenteric lymph nodes (MLN) were also analyzed. In addition, the effects of ERF on the change in the induction of dendritic cells (DCs) were evaluated.

RESULTS

The preventive effect of ERF on colitis was significantly superior to that of raw material rice bran or control group. An overexpression of inflammatory cytokine production was attenuated by ERF treatment, which was accompanied with a decrease in both the colonic mucosal damage and 5HT production. Furthermore, ERF significantly attenuated the T cell activation (CD4+CD69+) of spleen and MLN, and this characteristic was inherited by the retransferred mice. ERF significantly suppressed the growth of Clostiridium, and increased short-chain fatty acids (acetate, propionate and butyrate) content in colitis. The relatively hydrophilic fraction of ERF (ethanol-methanol soluble fraction) is therefore considered to have a potent ability to attenuate the induction of DCs.

CONCLUSION

A new prebiotic, ERF, reduced inflammation by modulating the colonic environment and regulating immune cell differentiation. Although a more detailed study is required, this study showed the promising anti-inflammatory effects of an adjunctive prebiotic treatment for IBD.

Lactic acid fermentation of germinated barley fiber and proliferative function of colonic epithelial cells in loperamide-induced rats

To develop a functional food from the dietary fiber fraction of germinated barley (Hordeum vulgare L.) (GBF), lactic acid fermentation was attempted using Lactobacillus acidophilus, Streptococcus thermophilus, and Bifidobacterium bifidus. The quality characteristics of the lactic acid-fermented product and its effect on gastrointestinal function in an animal model were examined. The anaerobic fermentation of 1% and 2% GBF yielded lactic acid bacteria at 8.9 +/- 1.0 x 10(8) and 1.6 +/- 0.2 x 10(9) colony-forming units/mL, and it was considered acceptable for consumption by sensory assessment. To determine the effect on gastrointestinal function, Sprague-Dawley rats were fed with three types of diets: a normal chow diet and chow diets supplemented with 10% lactic acid bacteria or a yogurt fermented with 2% GBF (GBFY). The rats fed GBFY for 6 weeks gained less body weight, excreted more fecal mass, and had improved gastrointestinal transit as examined with barium sulfate. The effect of GBFY on colonic epithelial proliferation was investigated through loperamide (LPM)-induced constipation in rats. The rats fed with GBFY for 6 weeks were intraperitoneally administered LPM twice daily for 7 days. GBFY supplementation decreased fecal excretion and moisture content in feces and depleted goblet cells as observed by hematoxylin and eosin stain. However, the rats supplemented with GBFY prior to the LPM administration had enhanced bowel movement, mucin secretion, and production of short-chain fatty acids compared with values for the LPM-alone group. Immunohistochemistry revealed that the GBFY supplement increased the numbers of nuclei stained positively for Ki-67 and extended from the base to the middle zone of crypts. These results indicate that GBFY alleviates constipation via the proliferation of the colonic crypts in LPM-administered rats.

Daily intake of high dietary fiber slows accelerated colonic transit induced by restrain stress in rats

BACKGROUND

Stress and central corticotropin releasing factor (CRF) are contributing factors to the pathogenesis of irritable bowel syndrome (IBS). It has been shown that restraint stress and central CRF stimulate colonic motility in rats. Short-chain fatty acids (SCFAs) are produced by bacterial fermentation from dietary fibers. It is controversial whether daily intake of dietary fiber is beneficial for patients with diarrhea-predominant IBS. We studied whether dietary fiber intake affects colonic transit and motility stimulated by restraint stress and central CRF in rats.

METHODS

Corn starch is digested almost completely in the small intestine, while potato starch shows substantial resistance to alpha-amylase and its consumption leads to stimulation of large-bowel fermentation. Four weeks after a corn starch, potato starch, or usual diet (rat chow), colonic transit and motility stimulated by restraint stress and intracisternal (ic) injection of CRF were studied. Fecal concentration of SCFAs in the cecum was measured by high-performance liquid chromatography (HPLC).

RESULTS

Four-week treatment with potato starch diet significantly increased cecal concentrations of SCFAs, compared to treatment with corn starch diet. Accelerated colonic transit induced by stress and ic injection of CRF (1 microg) were significantly attenuated in rats receiving potato starch diet compared to rats receiving corn starch diet. The incidence of unformed stool (diarrhea) induced by stress and CRF was also reduced in rats receiving potato starch diet compared to rats receiving corn starch diet and usual diet.

CONCLUSION

It is suggested that daily intake of a high-fiber diet may prevent stress- and CRF-induced acceleration of colonic transit and diarrhea. This study may contribute to treatment for the patients of diarrhea-predominant IBS.

Review article: the role of butyrate on colonic function

BACKGROUND

Butyrate, a short-chain fatty acid, is a main end-product of intestinal microbial fermentation of mainly dietary fibre. Butyrate is an important energy source for intestinal epithelial cells and plays a role in the maintenance of colonic homeostasis.

AIM

To provide an overview on the present knowledge of the bioactivity of butyrate, emphasizing effects and possible mechanisms of action in relation to human colonic function.

METHODS

A PubMed search was performed to select relevant publications using the search terms: 'butyrate, short-chain fatty acid, fibre, colon, inflammation, carcinogenesis, barrier, oxidative stress, permeability and satiety'.

RESULTS

Butyrate exerts potent effects on a variety of colonic mucosal functions such as inhibition of inflammation and carcinogenesis, reinforcing various components of the colonic defence barrier and decreasing oxidative stress. In addition, butyrate may promote satiety. Two important mechanisms include the inhibition of nuclear factor kappa B activation and histone deacetylation. However, the observed effects of butyrate largely depend on concentrations and models used and human data are still limited.

CONCLUSION

Although most studies point towards beneficial effects of butyrate, more human in vivo studies are needed to contribute to our current understanding of butyrate-mediated effects on colonic function in health and disease.

Insulin-like growth factor binding protein-3 inhibits colitis-induced carcinogenesis

PURPOSE

Chronic inflammation in the setting of inflammatory bowel disease is thought to result in altered epithelial cell growth regulation and ultimately carcinogenesis. This loss in cell growth regulation may be partially caused by a decrease in circulating intact insulin-like growth factor binding protein-3 (IFGB-3) as a result of chronic inflammation. This study evaluates the effect of IFGB-3 on carcinogenesis in the setting of colitis.

METHODS

A previously described animal model for colitis-induced carcinogenesis was used. Colitis was induced in both wild-type and IFGB-3 transgenic CD1 mice with a one-week oral exposure to dextran sodium sulfate (2 percent in drinking water). All mice received a single intraperitoneal administration (10 mg/kg body weight) of a genotoxic colonic carcinogen, azoxymethane. At Week 20, the animals were killed and their colons were excised. The colons were examined by a pathologist under blinded conditions. Criteria assessed included the severity of colitis, number of aberrant crypt foci per mouse colon, incidence of colonic adenomas, and mean size of colonic adenomas.

RESULTS

A total of 20 mice (10 in each group) were included in the study. The severity of colitis was not significantly different between the two groups (mean colitis score wild-type = 13.2; IFGB-3 transgenic = 11; P = not significant). The average number of aberrant crypt foci per colon was significantly lower in the IFGB-3 transgenic mice compared with the wild-type mice (1.5 +/- 1.4 vs. 4.5 +/- 2.7, respectively; P < 0.0001). The number of adenomas per colon was significantly lower in IFGB-3 transgenic group (1.2 +/- 1.8) compared with the wild-type mice (3.7 +/- 2.7; P = 0.005). In addition the average size of adenomas was significantly smaller in IFGB-3 transgenic mice (1.4 +/- 1.3 mm) compared with the wild-type mice (2.6 +/- 2 mm; P = 0.013).

CONCLUSIONS

IFGB-3 significantly reduces the development of colonic tumors and precursor lesions in the setting of induced murine colitis. It is possible that the loss of IFGB-3 as a result of chronic inflammation may be associated with an increased rate of carcinogenesis in the inflammatory bowel disease setting. Although further studies are necessary, in theory, inhibiting the depletion of IFGB-3 or replacement of IFGB-3 may serve as a novel treatment strategy to prevent the development of colitis-induced carcinogenesis.

Effect of oral administration of Butyrivibrio fibrisolvens MDT-1 on experimental enterocolitis in mice

Butyrivibrio fibrisolvens MDT-1, a butyrate-producing strain, was evaluated for use as a probiotic to prevent enterocolitis. Oral administration of the MDT-1 strain (10(9) CFU/dose) alleviated the symptoms of colitis (including body weight loss, diarrhea, bloody stool, organic disorder, and mucosal damage) that are induced in mice drinking water that contains 3.0% dextran sulfate sodium. In addition, myeloperoxidase (MPO) activity levels in colonic tissue were reduced, suggesting that MDT-1 mitigates bowel inflammation. The addition of MDT-1 culture supernatant inhibited the growth of nine clinical isolates of Campylobacter jejuni and Campylobacter coli that could potentially cause enterocolitis. Infection of mice with C. coli 11580-3, one of the isolates inhibited by MDT-1 in vitro, resulted in diarrhea, mucosal damage, increased MPO activity levels in colonic tissue, increased numbers of C. coli in the cecum, and decreased body weight gain. However, administration of MDT-1 to mice, prior to and during C. coli infection, reduced these effects. These results suggest that Campylobacter-induced enterocolitis can be alleviated by using B. fibrisolvens as a probiotic.

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.

Effect of Clostridium butyricum on fecal flora in Helicobacter pylori eradication therapy

AIM

To investigate the effect of probiotic bacterium, Clostridium butyricum MIYAIRI 588 strain (CBM) on the changes of the fecal flora in Helicobacter pylori (H. pylori) treatment.

METHODS

Thirty-five patients with gastric or duodenal ulcers positive for H. pylori were randomized either to 1 wk amoxicillin, clarithromycin, lansoprazole (Group 1) or to the same regimen supplemented with CBM 7 d ahead of the triple therapy (Group 2). Stool samples were collected before and 2, 4, 7, 15, and 22 d after the starting eradication therapy, and were examined intestinal flora. Patients were required to keep a diary record of their condition.

RESULTS

Obligate anaerobes decreased significantly on d 2, 4, 8 and 15 in Group 1. On the other hand, they did not decrease significantly in Group 2. The Escherichia coli was dominant bacterium in Enterobacteriaceae, but that was replaced by other species such as Klebsiella and Enterobacter after eradication in Group 1. The change was suppressed in Group 2. Abdominal symptoms were less frequent in Group 2 than in Group 1.

CONCLUSION

The combined use of CBM reduced the changes in the intestinal flora and decreased the incidence of gastrointestinal side effects.

Oral administration of butyrivibrio fibrisolvens, a butyrate-producing bacterium, decreases the formation of aberrant crypt foci in the colon and rectum of mice

Butyrivibrio fibrisolvens, a butyrate-producing ruminal bacterium, was evaluated for use as a probiotic to prevent colorectal cancer. Oral administration to Jcl:ICR mice of a new strain of B. fibrisolvens (MDT-1) that produces butyrate at a high rate (10(9) cfu/dose) increased the rate of butyrate production by fecal microbes, suggesting that MDT-1 can grow in the gut. The number of colorectal aberrant crypt foci (ACF), putative preneoplastic lesions induced by 1,2-dimethylhydrazine, was reduced after MDT-1 administration (10(9) cfu/dose, 3 times/wk for 4 wk). The number of aberrant crypts (ACs), number of foci having 3 or 4 ACs per focus, and the percentage of mice having 3 or 4 ACs per focus were also reduced, suggesting that the progress of lesions was suppressed by MDT-1. Interestingly, the MDT-1 cell homogenate did not have a similar beneficial effect. MDT-1 had low beta-glucuronidase activity, and administration of MDT-1 reduced the beta-glucuronidase activity in the colorectal contents. The numbers of natural killer (NK) and NKT cells in the spleen were markedly enhanced in response to MDT-1. Decreased beta-glucuronidase activity and increased numbers of NK and NKT cells and butyrate production may explain in part why MDT-1 administration suppressed ACF formation. These results suggest that colorectal cancer may be prevented or suppressed by the utilization of MDT-1 as a probiotic. Administration of MDT-1 had no harmful effect on the health of mice at least for 3 mo.

Nonpathogenic Escherichia coli strain Nissle1917 prevents murine acute and chronic colitis

BACKGROUND

Nonpathogenic Escherichia coli strain Nissle1917 has been used as a probiotics in human inflammatory bowel disease; however, there are few reports examining its therapeutic effect on animal colitis models, and its therapeutic mechanisms remain unknown. The aim of this study was to elucidate the therapeutic effect and mechanism of Nissle1917 using murine acute and chronic colitis models.

METHODS

Two models were used. (1) Acute model: colitis was induced by administration of 1.3% dextran sodium sulfate for 7 days. Nissle1917 or phosphate-buffered saline were orally administered for 10 days. Mice were killed at day 10, and the colonic lesions were assessed macro- and microscopically. (2) Chronic model: IL-10 mice were treated with Nissle1917 or phosphate-buffered saline for 8 weeks. After 8 weeks of treatment, mice were killed to assess the colonic lesions macro- and microscopically. In the acute dextran sodium sulfate colitis model, viable, heat-killed, or genomic DNA of Nissle1917 was orally administered for 10 days, and the therapeutic effect was assessed.

RESULTS

In the acute model, Nissle1917 ameliorated body weight loss, disease activity index, and macro- and microscopic damage. In the chronic model, it also suppressed the mucosal inflammatory findings and histologic damages. Moreover, heat-killed Nissle1917 or its genomic DNA alone also ameliorated the acute DSS colitis and viable bacteria macro- and microscopically.

CONCLUSIONS

Nonpathogenic E. coli strain Nissle1917 prevents both acute and chronic colitis, and its anti-inflammatory effect is exhibited not only by viable bacteria but also by heat-killed bacteria or its DNA.

Effects of the soluble fibre pectin on intestinal cell proliferation, fecal short chain fatty acid production and microbial population

AIM

Although pectin, a dietary fibre, has been suggested to possess some trophic effects on the intestine, the mechanisms involved remain unclear. This study aimed to evaluate the effects of pectin on rat intestinal cell proliferation and the intraluminal environment.

METHODS

Control and pectin-fed rats were given a fibre-free elemental diet (ED) and an ED containing 2.5% pectin, respectively. On the 15th day, the length, weight and number of Ki-67-positive cells from each intestinal segment, and the short chain fatty acids (SCFAs) and microbial population in the caecum were measured. Plasma glucagon-like peptide-2 (GLP-2) concentration and GLP-2 receptor (GLP-2R) mRNA levels in the epithelium were also determined.

RESULTS

Pectin supplementation resulted in significant increases in the length, weight, and number of Ki-67-positive cells in the ileum, caecum and colon. Although pectin supplementation did not affect the caecal microbial flora that produced SCFAs, the caecal SCFA content was significantly increased. Pectin supplementation also induced an increase in the plasma GLP-2 concentration, but did not affect the GLP-2R mRNA levels in the small intestine.

CONCLUSIONS

The increases in the caecal SCFAs and plasma GLP-2 levels induced by pectin supplementation may cause mucosal proliferation in the lower intestinal tract.

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.

Dietary fiber down-regulates colonic tumor necrosis factor alpha and nitric oxide production in trinitrobenzenesulfonic acid-induced colitic rats

Previous studies have revealed the beneficial effects exerted by dietary fiber in human inflammatory bowel disease, which were associated with an increased production of SCFA in distal colon. The aim of the present study was to elucidate the probable mechanisms involved in the beneficial effects of a fiber-supplemented diet (5% Plantago ovata seeds) in the trinitrobenzenesulfonic acid (TNBS) model of rat colitis, with special attention to its effects on the production of some of the mediators involved in the inflammatory response, such as tumor necrosis factor alpha (TNFalpha) and nitric oxide (NO). Rats were fed the fiber-supplemented diet for 2 wk before TNBS colitis induction and thereafter until colonic evaluation 1 wk later. The results obtained showed that dietary fiber supplementation facilitated recovery from intestinal insult as evidenced both histologically, by a preservation of intestinal cytoarchitecture, and biochemically, by a significant reduction in colonic myeloperoxidase activity and by restoration of colonic glutathione levels. This intestinal anti-inflammatory effect was associated with lower TNFalpha levels and lower NO synthase activity in the inflamed colon, showing significant differences when compared with nontreated colitic rats. Moreover, the intestinal contents from fiber-treated colitic rats showed a significantly higher production of SCFA, mainly butyrate and propionate. We conclude that the increased production of these SCFA may contribute to recovery of damaged colonic mucosa because they constitute substrates for the colonocyte and, additionally, that they can inhibit the production of proinflammatory mediators, such as TNFalpha and NO.

Probiotics and Functional Foods in Gastrointestinal Disorders

Probiotics are live microbial food supplements that benefit the host animal by improving intestinal microbial balance. When they are fed in yogurts, they can fall into the category of functional foods. Functional foods include these probiotics, prebiotics, and, to a certain extent, dietary fiber. Prebiotics are nondigestible food ingredients or supplements that alter the intestinal flora and stimulate the growth of healthy bacteria. Dietary fibers are part of plant foods that are nonstarch polysaccharides and are poorly digested or not digested by human enzymes. The physiologic process in which probiotics and functional foods affect the intestinal flora is through the balance of the intestinal microecology. This review looks at the four major components of intestinal microecology and describes the probiotics in use today and their clinical relevance. Although probiotics hold great promise and appear to be useful in some settings, more clinical study is needed to firmly establish the relevance of probiotic therapy.

Germinated barley foodstuff exhibits different adsorption properties for hydrophilic versus hydrophobic bile acids

BACKGROUND/AIMS

Germinated barley foodstuff (GBF), a type of dietary fiber, exhibits therapeutic effects in ulcerative colitis (UC) patients. However, the precise mechanisms responsible for these effects are still under investigation. On the other hand, it has been suggested that bile salts in the gut lumen play an important role in the integrity of the intestinal mucosa. The aim of the present study was to investigate the ability of GBF to adsorb bile salts in vitro.

METHODS

The binding capacities of GBF, enzymatically digested GBF (GBF-fiber), and alpha-cellulose for unconjugated and conjugated bile salts were measured using Langmuir's method. The morphology of these fibers was observed by light and fluorescence microscopy.

RESULTS

GBF adsorbed bile salts very strongly, especially hydrophobic bile salts. Even after enzymatic digestion, the GBF fiber still exhibited strong binding capacity, whereas alpha-cellulose exhibited very low binding capacity. Microscopically, GBF consists mainly of aleurone, a lattice-like cell wall with cytoplasm enclosed. After enzymatic digestion, the cytoplasm was also digested.

CONCLUSION

GBF possesses a great capacity to adsorb bile salts. This may be part of the mechanism for the therapeutic effects of GBF in UC patients.

Predominance of caecal injury in a new dextran sulphate sodium treatment in rats: histopathological and fermentative characteristics

OBJECTIVES

Cyclic administrations of dextran sulphate sodium (DSS) alternating with distilled water usually induce chronic colitis after a few weeks. In order to obtain stable chronic colitis (without recovery or relapse) in a few days, a new continuous DSS treatment was tested and characterized. Short-chain fatty acids (SCFAs), which remain poorly documented in experimental colitis, were also investigated.

METHODS

Thirty-six Sprague-Dawley rats were treated with 5% DSS for 7 days (DI) followed by 3% DSS for 7 days (DM) or 14 days (DF). Control rats received only water. Inflammatory injuries in the caecum and the colon were assessed by macroscopic (colon length, caecum weight, damages score) and histological parameters. SCFAs (acetate, propionate, butyrate) were quantified individually in caecal, proximal and distal contents.

RESULTS

Macroscopic and histological observations revealed that this continuous DSS treatment induced acute inflammation (DI) followed rapidly by chronic active colitis. The latter was uncommonly predominant in the caecum and the distal colon, and was also associated with some fermentative disturbances. Caecal SCFA concentrations decreased with DSS at DI and DM. The molar ratio of caecal butyrate increased with DSS. Acetate decreased in the colon while propionate increased.

CONCLUSION

This new DSS treatment is able to induce in a few days stable chronic inflammation with caecal and distal predominant injuries, and mild fermentative caeco-colonic alterations. This model could contribute to the study of potential anti-inflammatory effects of prebiotics.

Probiotics and functional foods in gastrointestinal disorders

Probiotics are live microbial food supplements that benefit the host animal by improving intestinal microbial balance. When they are fed in yogurts, they can fall into the category of functional foods. Functional foods include these probiotics, prebiotics, and, to a certain extent, dietary fiber. Prebiotics are nondigestible food ingredients or supplements that alter the intestinal flora and stimulate the growth of healthy bacteria. Dietary fibers are part of plant foods that are nonstarch polysaccharides and are poorly digested or not digested by human enzymes. The physiologic process in which probiotics and functional foods affect the intestinal flora is through the balance of the intestinal microecology. This review looks at the four major components of intestinal microecology and describes the probiotics in use today and their clinical relevance. Although probiotics hold great promise and appear to be useful in some settings, more clinical study is needed to firmly establish the relevance of probiotic therapy.