Is there any place for alimentary probiotics, prebiotics or synbiotics, for patients with inflammatory bowel disease?

Prebiotics, Probiotics, Synbiotics, Paraprobiotics and Postbiotic Compounds in IBD

The increasing incidence of inflammatory bowel diseases (IBD) and the increasing severity of the course of these diseases create the need for developing new methods of therapy. The gut microbiome is extensively studied as a factor influencing the development and course of IBD. The composition of intestinal microbiota can be relatively easily modified by diet (i.e., prebiotics, mainly dietary fibers) and bacterial supplementation using beneficial bacteria strains called probiotics. Additionally, the effects of the improved microbiome could be enhanced or gained by using paraprobiotics (non-viable, inactivated bacteria or their components) and/or postbiotics (products of bacterial metabolism or equal synthetic products that beneficially modulate immunological response and inflammation). This study summarizes the recent works on prebiotics, probiotics, synbiotics (products merging pre- and probiotics), paraprobiotics and postbiotics in IBD.

The New Proactive Approach and Precision Medicine in Crohn's Disease

The proactive approach to Crohn's disease (CD) management advocates moving toward algorithmic tight-control scenarios that are designed for each CD phenotype to guide remission induction, maintenance therapy, active monitoring, and multidisciplinary care to manage the complexities of each inflammatory bowel disease (IBD) patient. This requires accurate initial clinical, laboratory, radiological, endoscopic, and/or tissue diagnosis for proper phenotypic stratification of each CD patient. A substantial proportion of patients in symptomatic remission have been reported to demonstrate evidence of active disease, with elevated fecal calprotectin(FC) and C-reactive protein (CRP) levels as a hallmark for mucosal inflammation. Active mucosal inflammation, and elevated CRP and fecal calprotectin (FC) have been shown to be good predictors of clinical relapse, disease progression, and complications in IBD patients. The next frontier of treatment is personalized medicine or precision medicine to help solve the problem of IBD heterogeneity and variable responses to treatment. Personalized medicine has the potential to increase the efficacy and/or reduce potential adverse effects of treatment for each CD phenotype. However, there is currently an unmet need for better elucidation of the inflammatory biopathways and genetic signatures of each IBD phenotype, so personalized medicine can specifically target the underlying cause of the disease and provide maximal efficacy to each patient.

Rebuilding the Gut Microbiota Ecosystem

A microbial ecosystem in which bacteria no longer live in a mutualistic association is called dysbiotic. Gut microbiota dysbiosis is a condition related with the pathogenesis of intestinal illnesses (irritable bowel syndrome, celiac disease, and inflammatory bowel disease) and extra-intestinal illnesses (obesity, metabolic disorder, cardiovascular syndrome, allergy, and asthma). Dysbiosis status has been related to various important pathologies, and many therapeutic strategies aimed at restoring the balance of the intestinal ecosystem have been implemented. These strategies include the administration of probiotics, prebiotics, and synbiotics; phage therapy; fecal transplantation; bacterial consortium transplantation; and a still poorly investigated approach based on predatory bacteria. This review discusses the various aspects of these strategies to counteract intestinal dysbiosis.

Probiotics for inflammatory bowel diseases: a promising adjuvant treatment

Inflammatory bowel diseases (IBD) encompass ulcerative colitis (UC), Crohn's disease (CD) and indeterminate colitis (IC), characterising chronic inflammation in the gastrointestinal tract, associated with changes in the immune system and in the intestinal microbiota. Thus, probiotics may offer an alternative or adjuvant approach to conventional therapy. The present review aims to summarise the mechanisms of action of probiotics in IBD and their therapeutic effects. Most of the studies suggest that probiotics are effective in the treatment of UC, especially when several strains are concomitantly administered. Species of Lactobacillus and Bifidobacterium genres are the most commonly used, and some studies even indicate that it is possible to replace medical therapy with probiotic supplementation. Regarding CD, the results of clinical trials are controversial and do not support the use of probiotics in this disease. In conclusion, probiotic supplementation is a promising adjuvant treatment in UC, but not in CD.

The potential role of fecal microbiota transplantation in the treatment of inflammatory Bowel disease

Inflammatory bowel disease (IBD) is a chronic inflammatory disorder of an unknown etiology. Its pathogenesis involves an interplay of infectious, genetic, environmental, and immunological factors. The current therapeutic options have various limitations in terms of cost, side effect profile, and the development of drug resistance and dependence. Therefore, there is a need to develop future therapeutic options which are safe and effective to control the inflammatory process. This review focuses in a method for the administration of fecal matters (which contains a mixture of various commensals) from a healthy donor to the inflamed colon called fecal microbiota transplantation (FMT) aiming to correct the underlying dysbiosis in the gut as one of the major driving force for the inflammatory process. IBD patients have reduced number of protective (e.g., clostridia and bacteroids) and increased number of pathogenic (e.g., adhesive invasive E. coli and mycobacterium avium paratuberculosis) commensals, and this method is aimed to shift these changes in the gut. Recent studies from animal models and clinical trials suggest promising effects of this method in treating patients with IBD, but more studies are urgently needed to confirm its efficacy and safety, since the etiology of this chronic inflammatory disease is not fully understood and caution should be taken when transplanting fecal matters between individuals which might transfer other infectious organisms and diseases.

Fine-tuning of the mucosal barrier and metabolic systems using the diet-microbial metabolite axis

The human intestinal microbiota has profound effects on human physiology, including the development and maintenance of the host immune and metabolic systems. Under physiological conditions, the intestinal microbiota maintains a symbiotic relationship with the host. Abnormalities in the host-microbe relationship, however, have been implicated in multiple disorders such as inflammatory bowel diseases (IBDs), metabolic syndrome, and autoimmune diseases. There is a close correlation between dietary factors and the microbial composition in the gut. Long-term dietary habits influence the composition of the gut microbial community and consequently alter microbial metabolic activity. The diet-microbiota axis plays a vital role in the regulation of the host immune system, at least partly through altering microbial metabolism. In this review, we will describe the current findings regarding how dietary factors and microbial metabolites regulate the host immune system.

Targeting the Microbiome in Inflammatory Bowel Disease: Critical Evaluation of Current Concepts and Moving to New Horizons

Microorganisms present in the intestine possess proinflammatory or anti-inflammatory activities which may modulate inflammatory bowel disease (IBD). The concepts followed by researchers in trying to target the microbiota in IBD were to decrease pathogens or pathobionts, or only the microbial load, and more recently, to favor growth and persistence of favorable microorganisms. We review, here, those concepts and critically analyze the clinical data (especially randomized controlled trials) obtained using antibiotics and probiotics. We eventually present and criticize the rational and data obtained so far following new research strategies including the use of new probiotics, genetically modified organisms and fecal transplantation.

Th17 Cells as Potential Probiotic Therapeutic Targets in Inflammatory Bowel Diseases

Inflammatory bowel diseases (IBD) are characterized by wasting and chronic intestinal inflammation triggered by various cytokine-mediated pathways. In recent years, it was shown that T helper 17 (Th17) cells are involved in the pathogenesis of IBD, which makes them an attractive therapeutic target. Th17 cells preferentially produce interleukin (IL)-17A–F as signature cytokines. The role of the interplay between host genetics and intestinal microbiota in the pathogenesis of IBD was demonstrated. Probiotics are live microorganisms that when orally ingested in adequate amounts, confer a health benefit to the host by modulating the enteric flora or by stimulating the local immune system. Several studies indicated the effectiveness of probiotics in preventing and treating IBD (ulcerative colitis, and Crohn’s disease). Furthermore, there is mounting evidence of probiotics selectively targeting the Th17 lineage in the prevention and management of inflammatory and autoimmune diseases such as IBD. This review highlights critical roles of Th17 cells in the pathogenesis of IBD and the rationale for using probiotics as a novel therapeutic approach for IBD through manipulation of Th17 cells. The potential molecular mechanisms by which probiotics modulate Th17 cells differentiation and production are also discussed.

Small molecule immunomodulins from cultures of the human microbiome member Lactobacillus plantarum

Lactobacillus plantarum strains are noted for their presence in the human gastrointestinal tract and are distinguished for their immunomodulatory actions and therapeutic applications. Despite the uncertainty in the underlining molecular mechanisms, recent evidence suggests that L. plantarum secretes immunomodulatory agents that alter immunological signaling cascades. Elaboration of these metabolic products from L. plantarum strain WCFS1 was demonstrated previously to correlate with the mid-log-stationary transition, perhaps consistent with secondary metabolite expression. Here, we present the metabolomic shifts revealed by principal component analysis that correspond to the mid-log-stationary transition of L. plantarum, and identify pyroglutamic (pyro) dipeptides within this transition as correlative with the immunomodulatory actions. Four of these (pyro-phenylalanine, pyro-leucine, pyro-isoleucine, pyro-tryptophan) were characterized and the two dominant members, pyro-phenylalanine and pyro-tryptophan, were directly interrogated for immunomodulatory activity through in vivo administration using C57BL/6 mice. Administration of these compounds resulted in decreased production of pro-inflammatory cytokine interferon (IFN)-gamma, which is of noted importance in gastrointestinal immune homeostasis.

Investigation of inpatient probiotic use at an academic medical center

OBJECTIVES

Despite the widespread use of probiotics, there are limited data regarding their safety. The aims of this study were to characterize inpatient probiotic use and to determine the incidence of probiotic-related bloodstream infections due to Lactobacillus acidophilus/Lactobacillus bulgaricus.

METHODS

This study was a two-part retrospective study conducted at a large academic medical center. The first part was the characterization of probiotic use during 2007-2008, which included the type of prescribing provider, choice of probiotic prescribed, indications for use, and presence of potential risk factors for probiotic infection among recipients; the second part was the determination of the incidence of probiotic-related bloodstream infections due to L. acidophilus/L. bulgaricus for September 2000-August 2008.

RESULTS

Probiotic use was uncommon (0.4%). Ninety-six percent of patients received Lactobacillus-based compounds. Use was common in patients at theoretical risk for probiotic infection. The maximum estimated incidence of probiotic-related bacteremia due to L. acidophilus/L. bulgaricus during the 8-year period was 0.2%.

CONCLUSIONS

L. acidophilus/L. bulgaricus probiotic use at our institution appeared to be associated with a minimal risk of probiotic-related infection, even though it was used at a high frequency among inpatients who could be considered at high theoretical risk for probiotic-related bloodstream infection.

Genotoxicity of Escherichia coli Nissle 1917 strain cannot be dissociated from its probiotic activity

Oral administration of the probiotic bacterium Escherichia coli Nissle 1917 improves chronic inflammatory bowel diseases, but the molecular basis for this therapeutic efficacy is unknown. E. coli Nissle 1917 harbors a cluster of genes coding for the biosynthesis of hybrid nonribosomal peptide-polyketide(s). This biosynthetic pathway confers the ability for bacteria to induce DNA double strand breaks in eukaryotic cells. Here we reveal that inactivation of the clbA gene within this genomic island abrogated the ability for the strain to induce DNA damage and chromosomal abnormalities in non-transformed cultured rat intestinal epithelial cells but is required for the probiotic activity of E. coli Nissle 1917. Thus, evaluation of colitis severity induced in rodent fed with E. coli Nissle 1917 or an isogenic non-genotoxic mutant demonstrated the need for a functional biosynthetic pathway both in the amelioration of the disease and in the modulation of cytokine expression. Feeding rodents with a complemented strain for which genotoxicity was restored confirmed that this biosynthetic pathway contributes to the health benefits of the probiotic by modulating its immunomodulatory properties. Our data provide additional evidence for the benefit of this currently used probiotic in colitis but remind us that an efficient probiotic may also have side effects as any other medication.

Nutritional and probiotic supplementation in colitis models

In vitro and animals models have long been used to study human diseases and identify novel therapeutic approaches that can be applied to combat these conditions. Ulcerative colitis and Crohn's disease are the two main entities of inflammatory bowel disease (IBD). There is an intricate relationship between IBD features in human patients, in vitro and animal colitis models, mechanisms and possible therapeutic approaches in these models, and strategies that can be extrapolated and applied in humans. Malnutrition, particularly protein-energy malnutrition and vitamin and micronutrient deficiencies, as well as dysregulation of the intestinal microbiota, are common features of IBD. Based on these observations, dietary supplementation with essential nutrients known to be in short supply in the diet in IBD patients and with other molecules believed to provide beneficial anti-inflammatory effects, as well as with probiotic organisms that stimulate immune functions and resistance to infection has been tested in colitis models. Here we review current knowledge on nutritional and probiotic supplementation in in vitro and animal colitis models. While some of these strategies require further fine-tuning before they can be applied in human IBD patients, their intended purpose is to prevent, delay or treat disease symptoms in a non-pharmaceutical manner.

Effects of a Lactobacillus reuteri BR11 mutant deficient in the cystine-transport system in a rat model of inflammatory bowel disease

BACKGROUND

Inflammatory bowel disease (IBD) is a chronic inflammatory disorder of the gastrointestinal tract associated with altered composition of the gut microbiota. Lactobacillus reuteri BR11 (BR11) has recently been reported to reduce the severity of experimental IBD because of its probiotic properties possibly attributed to a mechanism of thiol production via its unique cysteine/cystine-transport system.

AIM

We compared BR11 and a BR11 mutant deficient in the cystine-uptake system (PNG201), for their capacity to reduce the severity of experimental colitis.

METHODS

Male Sprague-Dawley rats (n = 8 per group) were gavaged (1 ml/day) with skim milk, BR11 or PNG201 (1 × 10(9) CFU/ml) for 12 days. Rats consumed either water or 2% dextran sulfate sodium in drinking water from days 6 to 12 to induce colitis. Metabolism data, disease activity index, intestinal mucin profile, and histological analyses were assessed and compared by ANOVA.

RESULTS

Assessed histologically, DSS administration resulted in significant colonic deterioration, including loss of crypt area and increased damage severity. BR11 administration only partially alleviated the DSS effects, with a minor improvement in crypt area (P < 0.05). Administration of the PNG201 mutant strain to colitic animals failed to achieve significance (P > 0.05) against the DSS control for any of the end-points. However, the mutant strain induced significantly greater (P < 0.05) histological severity compared with BR11-treated colitic animals, indicative of possible exacerbation of colitis.

CONCLUSIONS

The cystine-uptake system only minimally affects the biological effects of BR11, as evidenced by histological and macroscopic colitic changes.

Lessons from probiotic-host interaction studies in murine models of experimental colitis

In inflammatory bowel diseases (IBD), it is known that besides genetic and environmental factors (e.g. diet, drugs, stress), the microbiota play an important role in the pathogenesis. Patients with IBD have an altered microbiota (dysbiosis) and therefore, probiotics, defined as 'live micro-organisms that when administered in adequate amounts can confer a health benefit on the host', have been suggested as nutritional supplements to restore these imbalances. The best response on probiotics among the different types of IBD appears to be in the case of ulcerative colitis. Although probiotics show promise in IBD in both clinical and animal studies, further mechanistic studies are necessary to optimize the use of probiotics as supporting therapy in IBD. Murine models of experimental colitis have been used for decades to study this pathology, and these models have been proven useful to search for new therapeutic approaches. The purpose of this review is to summarize probiotic-host interaction studies in murine models of experimental colitis and to evaluate how these models can further help in understanding these complex interactions. Unraveling the molecular mechanisms behind the beneficial effects will assist in better and possibly more efficient probiotic formulations.

Lactobacillus paracasei reduces intestinal inflammation in adoptive transfer mouse model of experimental colitis

Studies showed that specific probiotics provide therapeutic benefits in inflammatory bowel disease. In vitro evidence suggested that Lactobacillus paracasei also called ST11 (CNCM I-2116) is a potent strain with immune modulation properties. However, little is known about its capacity to alleviate inflammatory symptoms in vivo In this context, the main objective of this study was to investigate the role of ST11 on intestinal inflammation using the adoptive transfer mouse model of experimental colitis. Rag2^−/− recipient mice were fed with ST11 (10⁹ CFU/day)a month prior toinduce colitis by adoptive transfer of naive T cells. One month later, in clear contrast to nonfed mice, weight loss was significantly reduced by 50% in ST11-fed mice. Further analysis of colon specimens revealed a significant reduction neutrophil infiltration and mucosal expression of IL1β, IL-6, and IL12 proinflammatory cytokines, whereas no consistent differences in expression of antibacterial peptides or tight junction proteins were observed between PBS and ST11-fed mice. All together, our results demonstrate that oral administration of ST11 was safe and had a significant preventive effect on colitis. We conclude that probiotics such as Lactobacillus paracasei harbor worthwhile in vivo immunomodulatory properties to prevent intestinal inflammation by nutritional approaches.

Oral administration of Parabacteroides distasonis antigens attenuates experimental murine colitis through modulation of immunity and microbiota composition

Commensal bacteria have been shown to modulate the host mucosal immune system. Here, we report that oral treatment of BALB/c mice with components from the commensal, Parabacteroides distasonis, significantly reduces the severity of intestinal inflammation in murine models of acute and chronic colitis induced by dextran sulphate sodium (DSS). The membranous fraction of P. distasonis (mPd) prevented DSS-induced increases in several proinflammatory cytokines, increased mPd-specific serum antibodies and stabilized the intestinal microbial ecology. The anti-colitic effect of oral mPd was not observed in severe combined immunodeficient mice and probably involved induction of specific antibody responses and stabilization of the intestinal microbiota. Our results suggest that specific bacterial components derived from the commensal bacterium, P. distasonis, may be useful in the development of new therapeutic strategies for chronic inflammatory disorders such as inflammatory bowel disease.

Regulation of the polymeric immunoglobulin receptor in intestinal epithelial cells by Enterobacteriaceae: implications for mucosal homeostasis

The commensal microbiota of the human colon profoundly impacts host gene expression and mucosal homeostasis. Secretory IgA antibodies, which influence the composition of the intestinal microbiota and provide immunity against pathogens, are transported across intestinal epithelial cells (IEC) by the polymeric immunoglobulin receptor (pIgR). To compare the effects of different colonic bacteria on pIgR expression, the human IEC line HT-29 was stimulated with various species representing the 4 major phyla of colonic bacteria. Only bacteria from the family Enterobacteriaceae (phylum Proteobacteria) induced expression of pIgR and other target genes of bacterial pattern recognition receptors. HT-29 cells responded to purified ligands for Toll-like receptor (TLR)4 but not TLR2. Expression of pIgR and transport of IgA were significantly reduced in colons of mice deficient in the TLR adaptor MyD88, consistent with a role for TLR signaling in the regulation of pIgR by colonic bacteria. Induction of pIgR expression in HT-29 cells required NF-kappaB signaling but not MAPK signaling, in contrast to the requirement for both NF-kappaB and MAPK signaling for induction of pro-inflammatory genes. These results suggest that commensal Enterobacteriaceae may promote intestinal homeostasis by enhancing pIgR expression in IEC.

Probiotic yeasts: Anti-inflammatory potential of various non-pathogenic strains in experimental colitis in mice

AIM: To evaluate the in vitro immunomodulation capacity of various non-pathogenic yeast strains and to investigate the ability of some of these food grade yeasts to prevent experimental colitis in mice.

METHODS: In vitro immunomodulation was assessed by measuring cytokines [interleukin (IL)-12p70, IL-10, tumor necrosis factor and interferon γ] released by human peripheral blood mononuclear cells after 24 h stimulation with 6 live yeast strains (Saccharomyces ssp.) and with bacterial reference strains. A murine model of acute 2-4-6-trinitrobenzene sulfonic acid (TNBS)-colitis was next used to evaluate the distinct prophylactic protective capacities of three yeast strains compared with the performance of prednisolone treatment.

RESULTS: The six yeast strains all showed similar non-discriminating anti-inflammatory potential when tested on immunocompetent cells in vitro. However, although they exhibited similar colonization patterns in vivo, some yeast strains showed significant anti-inflammatory activities in the TNBS-induced colitis model, whereas others had weaker or no preventive effect at all, as evidenced by colitis markers (body-weight loss, macroscopic and histological scores, myeloperoxidase activities and blood inflammatory markers).

CONCLUSION: A careful selection of strains is required among the biodiversity of yeasts for specific clinical studies, including applications in inflammatory bowel disease and other therapeutic uses.

Clinical trial: probiotic treatment of acute distal ulcerative colitis with rectally administered Escherichia coli Nissle 1917 (EcN)

BACKGROUND

Probiotics are effective in inflammatory bowel diseases. Clinical effectiveness and dose dependency of E. coli Nissle (EcN) enemas were investigated in ulcerative colitis (UC).

METHODS

In a double-blind study, 90 patients with moderate distal activity in UC were randomly assigned to treatment with either 40, 20, or 10 ml enemas (N = 24, 23, 23) containing 10E8 EcN/ml or placebo (N = 20). The study medication was taken once daily for at least 2 weeks. After 2, 4 and/or 8 weeks the clinical DAI was assessed together with tolerance to treatment. Patients who reached clinical DAI <or= 2 within that time were regarded as responders.

RESULTS

According to ITT analysis the number of responders was not significantly higher in the EcN group than in the placebo group (p = 0.4430, 2-sided). However, the Jonckheere-Terpstra rank correlation for dose-dependent efficacy indicated a significant correlation of per-protocol responder rates (p = 0.0446, 2-sided). Time to remission was shortest with EcN 40 ml, followed by EcN 20 ml. The number of adverse events did not differ notably.

CONCLUSION

In contrast to ITT analysis, efficacy of rectal EcN application was significant in PP and points to EcN as a well tolerated treatment alternative in moderate distal UC.

TRIAL REGISTRATION

German Clinical Trials Register DRK00000234.

Current level of consensus on probiotic science--report of an expert meeting--London, 23 November 2009

The present paper summarizes the consensus views of a group of 9 European clinicians and scientists on the current state of scientific knowledge on probiotics, covering those areas where there is substantial evidence for beneficial effects and those where the evidence base is poor or inconsistent. There was general agreement that probiotic effects were species and often strain specific. The experts agreed that some probiotics were effective in reducing the incidence and duration of rotavirus diarrhoea in infants, antibiotic-associated diarrhoea in adults and, for certain probiotics, Clostridium difficile infections. Some probiotics are associated with symptomatic improvements in irritable bowel syndrome and alleviation of digestive discomfort. Probiotics can reduce the frequency and severity of necrotizing enterocolitis in premature infants and have been shown to regulate intestinal immunity. Several other clinical effects of probiotics, including their role in inflammatory bowel disease, atopic dermatitis, respiratory or genito-urinary infections or H.pylori adjuvant treatment were thought promising but inconsistent.

Bacteria Coated by Polyphenols Acquire Potent Oxidant-Scavenging Capacities

Several microbial species, including probiotic lactic acid bacteria, have the ability to irreversibly bind a large variety of polyphenols (flavonoids) and anthocyanidins found in many colored fruits and vegetables and to enhance their total oxidant-scavenging capacities (TOSC). The binding of flavonoids to microbial surfaces was further increased by the cationic polyelectrolytes ligands poly-L-histidine, chlorhexidine and Copaxone®. This phenomenon was confirmed visually, by the FRAP, DPPH, cyclic voltammetry, Folin-Ciocalteu as well as by luminol-dependent chemiluminescence techniques employed to assay TOSC. The possibility is considered that clinically, microbial cells in the oral cavity and in the gastro intestinal tract, complexed with antioxidant polyphenols from nutrients and with cationic ligands, might increase the protection of mammalian cells against damage induced by excessive generation of reactive oxygen species during infections and inflammation.