Probiotics in the management of inflammatory bowel disease: a systematic review of intervention studies in adult patients

Live Combined Bacillus subtilis and Enterococcus faecium Ameliorate Murine Experimental Colitis by Immunosuppression

Live combined Bacillus subtilis and Enterococcus faecium ameliorate murine experimental colitis by immunosuppression manifested by downregulation of TLRs, macrophages, Th1, and Th2 but upregulation of Tregs.

Intestinal microbiota, probiotics and prebiotics in inflammatory bowel disease

It has been presumed that aberrant immune response to intestinal microorganisms in genetically predisposed individuals may play a major role in the pathogenesis of the inflammatory bowel disease, and there is a good deal of evidence supporting this hypothesis. Commensal enteric bacteria probably play a central role in pathogenesis, providing continuous antigenic stimulation that causes chronic intestinal injury. A strong biologic rationale supports the use of probiotics and prebiotics for inflammatory bowel disease therapy. Many probiotic strains exhibit anti-inflammatory properties through their effects on different immune cells, pro-inflammatory cytokine secretion depression, and the induction of anti-inflammatory cytokines. There is very strong evidence supporting the use of multispecies probiotic VSL#3 for the prevention or recurrence of postoperative pouchitis in patients. For treatment of active ulcerative colitis, as well as for maintenance therapy, the clinical evidence of efficacy is strongest for VSL#3 and Escherichia coli Nissle 1917. Moreover, some prebiotics, such as germinated barley foodstuff, Psyllium or oligofructose-enriched inulin, might provide some benefit in patients with active ulcerative colitis or ulcerative colitis in remission. The results of clinical trials in the treatment of active Crohn’s disease or the maintenance of its remission with probiotics and prebiotics are disappointing and do not support their use in this disease. The only exception is weak evidence of advantageous use of Saccharomyces boulardii concomitantly with medical therapy in maintenance treatment.

The probiotic mixture VSL#3 mediates both pro- and anti-inflammatory responses in bone marrow-derived dendritic cells from C57BL/6 and BALB/c mice

Probiotic bacteria express a wide range of molecular structures that bind to receptors on innate immune cells and mediate health-promoting effects in the host. We have recently demonstrated in a colitis model that favourable effects of the probiotic mixture VSL#3 may in part be due to the suppression of intestinal chemokine expression. To obtain more insights into the underlying mechanisms, in the present study, we analysed the modulation of bone marrow-derived dendritic cells (BM-DC) from BALB/c (T helper (Th)2 biased) v. C57BL/6 (Th1 biased) mice. Our findings showed that VSL#3 differed from pure Toll-like receptor (TLR) ligands by inducing the production of various cytokines, including IL-12 p70 subunit (IL-12p70), IL-23 and IL-10. Dedicated TLR arrays were employed to profile mRNA from BM-DC cultured with lipopolysaccharide (LPS), VSL#3, or a combination of both. This approach led to the identification of (1) a cluster of genes that were up- or down-regulated, irrespective of the stimulus, (2) a cluster of genes that were synergistically up-regulated by LPS and VSL#3 in BM-DC from C57BL/6 mice, but not in those from BALB/c mice, and (3) a cluster of LPS-induced genes that were suppressed by VSL#3, in particular chemokine genes. These data show that this probiotic mixture has both pro- and anti-inflammatory effects on BM-DC and suggest that their immune-modulating properties in vivo may depend on the genetic background of the host.

Are probiotics or prebiotics useful in pediatric irritable bowel syndrome or inflammatory bowel disease?

Treatment options for irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD) are notoriously either inadequate (IBS) or loaded with potentially serious side effects and risks (IBD). In recent years, a growing interest in effective and safer alternatives has focused on the potential role of probiotics and their metabolic substrates, prebiotics. It is in fact conceivable that the microbiome might be targeted by providing the metabolic fuel needed for the growth and expansion of beneficial microorganisms (prebiotics) or by administering to the host such microorganisms (probiotics). This review presents a concise update on currently available data, with a special emphasis on children. Data for prebiotics in IBS are scarce. Low doses have shown a beneficial effect, while high doses are counterproductive. On the contrary, several controlled trials of probiotics have yielded encouraging results. A meta-analysis including nine randomized clinical trials in children showed an improvement in abdominal pain for Lactobacillus GG, Lactobacillus reuteri DSM 17938, and the probiotic mixture VSL#3. The patients most benefiting from probiotics were those with predominant diarrhea or with a post-infectious IBS. In IBD, the use of prebiotics has been tested only rarely and in small scale clinical trials, with mixed results. As for probiotics, data in humans from about three dozens clinical trials offer mixed outcomes. So far, none of the tested probiotics has proven successful in Crohn’s disease, while in ulcerative colitis a recent meta-analysis on 12 clinical trials (1 of them in children) showed efficacy for the probiotic mixture VSL#3 in contributing to induce and to maintain remission. It is evident that this is a rapidly evolving and promising field; more data are very likely to yield a better understanding on what strains should be used in different specific clinical settings and in what doses.

Intestinal dysbiosis: novel mechanisms by which gut microbes trigger and prevent disease

New research has identified specific intestinal colonizing microbes that can have significant influence on health and disease. Evidence is reviewed supporting an association between Fusobacterium nucleatum and colon cancer and for a protective role of Faecalibacterium prausnitzii in inflammatory bowel disease, of Escherichia coli Nissle 1917 in acute intestinal inflammation, of Bifidobacterium infantis in neonatal necrotizing enterocolitis, and of Akkermansia muciniphila in obesity and diabetes. These novel bacteria are clinically relevant and present opportunities for more focused diagnosis of colon cancer and prevention of common diseases.

Ulcerative colitis as a polymicrobial infection characterized by sustained broken mucus barrier

To reduce medication for patients with ulcerative colitis (UC), we need to establish the etiology of UC. The intestinal microbiota of patients with inflammatory bowel disease (IBD) has been shown to differ from that of healthy controls and abundant data indicate that it changes in both composition and localization. Small intestinal bacterial overgrowth is significantly higher in IBD patients compared with controls. Probiotics have been investigated for their capacity to reduce the severity of UC. The luminal surfaces of the gastrointestinal tract are covered by a mucus layer. This normally acts as a barrier that does not allow bacteria to reach the epithelial cells and thus limits the direct contact between the host and the bacteria. The mucus layer in the colon comprises an inner layer that is firmly adherent to the intestinal mucosa, and an outer layer that can be washed off with minimal rinsing. Some bacteria can dissolve the protective inner mucus layer. Defects in renewal and formation of the inner mucus layer allow bacteria to reach the epithelium and have implications for the causes of colitis. In this review, important elements of UC pathology are thought to be the intestinal bacteria, gut mucus, and the mucosa-associated immune system.

Modulating the microbiota in inflammatory bowel diseases: prebiotics, probiotics or faecal transplantation?

Crohn's disease (CD) and ulcerative colitis (UC) are the two major phenotypes of inflammatory bowel diseases (IBD) which constitute a spectrum of chronic, debilitating diseases characterised by a relapsing inflammation of the intestinal mucosal lining. Evidence from a variety of disciplines implicates the intestinal microbiota in the pathogenesis of idiopathic IBD and their complications, including pouchitis. Many studies have reported a dysbiosis in IBD, characterised by a decrease in diversity, a decreased abundance of some dominant commensal members (such as Clostridium IV and XIVa) and an increase in detrimental bacteria (such as sulphate reducing bacteria and Escherichia coli). Therapies such as prebiotics and probiotics aim to selectively manipulate the intestinal microbiota and have been evaluated as an attractive therapeutic option with few side effects. The multispecies product VSL#3 was found effective in preventing and maintaining remission in pouchitis, whereas both VSL#3 and E. coli Nissle were effective in maintaining remission in UC. A more drastic approach to restore the composition of the microbiota and correct the underlying imbalance is a faecal microbiota transplantation (FMT). FMT has been successfully applied to treat patients with even recalcitrant Clostridium difficile infection. Particularly in UC, the majority of studies suggest that FMT may be an effective treatment option although the evidence is still limited. It is anticipated that our increasing knowledge on the composition and function of the intestinal microbiota components will allow in the future for a better selection of highly performing bacteria with specific functions required for specific benefits.

Preliminary evaluation of probiotic properties of Lactobacillus strains isolated from Sardinian dairy products

Twenty-three Lactobacillus strains of dairy origin were evaluated for some functional properties relevant to their use as probiotics. A preliminary subtractive screening based on the abilities to inhibit the growth of microbial pathogens and hydrolyze conjugated bile salts was applied, and six strains were selected for further characterization including survival under gastrointestinal environmental conditions, adhesion to gut epithelial tissue, enzymatic activity, and some safety properties. All selected strains maintained elevated cell numbers under conditions simulating passage through the human gastrointestinal tract, well comparable to the values obtained for the probiotic strain Lactobacillus rhamnosus GG, and were able to adhere to Caco-2 cells to various extents (from 3 to 20%). All strains exhibited high aminopeptidase, and absent or very low proteolytic and strong β-galactosidase activities; none was found to be haemolytic or to produce biogenic amines and all were susceptible to tetracycline, chloramphenicol, erythromycin, ampicillin, and amoxicillin/clavulanic acid. Our results indicate that the Lactobacillus strains analyzed could be considered appropriate probiotic candidates, due to resistance to GIT simulated conditions, antimicrobial activity, adhesion to Caco-2 cell-line, and absence of undesirable properties. They could be used as adjunct cultures for contributing to the quality and health related functional properties of dairy products.

Exploring & exploiting our 'other self' - does the microbiota hold the key to the future therapy in Crohn's?

Inflammatory bowel diseases (IBD) with its two major forms Crohn's disease (CD) and ulcerative colitis (UC) are chronic relapsing disorders leading to inflammation of the gastrointestinal tract. Although the precise aetiology of IBD remains unclear, several factors are believed to contribute to disease pathogenesis. Among these, the role of the intestinal microbiota has become more and more appreciated. Evidence from experimental and clinical studies strongly suggests that chronic intestinal inflammation results from a dysregulated immune response towards components of the microbiota in genetically susceptible hosts. The growing perception of the microbiota as a major driver of disease pathogenesis raises the question, if the intestinal microbiota can be used as a therapeutic target in CD. Based on what we know about host microbiota interactions in health and disease, the objective of this review is to address the question if the microbiota holds the key to the future therapy in CD.

Autoinducer-2 plays a crucial role in gut colonization and probiotic functionality of Bifidobacterium breve UCC2003

In the present study we show that luxS of Bifidobacterium breve UCC2003 is involved in the production of the interspecies signaling molecule autoinducer-2 (AI-2), and that this gene is essential for gastrointestinal colonization of a murine host, while it is also involved in providing protection against Salmonella infection in Caenorhabditis elegans. We demonstrate that a B. breve luxS-insertion mutant is significantly more susceptible to iron chelators than the WT strain and that this sensitivity can be partially reverted in the presence of the AI-2 precursor DPD. Furthermore, we show that several genes of an iron starvation-induced gene cluster, which are downregulated in the luxS-insertion mutant and which encodes a presumed iron-uptake system, are transcriptionally upregulated under in vivo conditions. Mutation of two genes of this cluster in B. breve UCC2003 renders the derived mutant strains sensitive to iron chelators while deficient in their ability to confer gut pathogen protection to Salmonella-infected nematodes. Since a functional luxS gene is present in all tested members of the genus Bifidobacterium, we conclude that bifidobacteria operate a LuxS-mediated system for gut colonization and pathogen protection that is correlated with iron acquisition.

Transport proteins promoting Escherichia coli pathogenesis

Escherichia coli is a genetically diverse species infecting hundreds of millions of people worldwide annually. We examined seven well-characterized E. coli pathogens causing urinary tract infections, gastroenteritis, pyelonephritis and haemorrhagic colitis. Their transport proteins were identified and compared with each other and a non-pathogenic E. coli K12 strain to identify transport proteins related to pathogenesis. Each pathogen possesses a unique set of protein secretion systems for export to the cell surface or for injecting effector proteins into host cells. Pathogens have increased numbers of iron siderophore receptors and ABC iron uptake transporters, but the numbers and types of low-affinity secondary iron carriers were uniform in all strains. The presence of outer membrane iron complex receptors and high-affinity ABC iron uptake systems correlated, suggesting co-evolution. Each pathovar encodes a different set of pore-forming toxins and virulence-related outer membrane proteins lacking in K12. Intracellular pathogens proved to have a characteristically distinctive set of nutrient uptake porters, different from those of extracellular pathogens. The results presented in this report provide information about transport systems relevant to various types of E. coli pathogenesis that can be exploited in future basic and applied studies.

Restoring the gut microbiome for the treatment of inflammatory bowel diseases

Fecal microbiota transplantation (FMT) is considered to be a highly successful therapy for recurrent and refractory Clostridium difficile infection (CDI) based on recent clinical trials. The pathogenesis of inflammatory bowel diseases (IBD) is thought to be due in part to perturbations in the gut microflora that disrupt homeostasis. FMT restores essential components of the microflora which could reverse the inflammatory processes observed in IBD. Case reports and series for the treatment of IBD by FMT have shown promise with regards to treatment success and safety despite the limitations of the reporting. Future studies will determine the optimal delivery and preparation of stool as well as the conditions under which the recipient will derive maximal benefit. The long term consequences of FMT with regards to infection, cancer, auto-immune, and metabolic diseases are not known and will require continued regulation and study. Despite these limitations, FMT may be beneficial for the treatment of ulcerative colitis and Crohn’s disease, particularly those with concurrent CDI or with pouchitis.

Impact of complementary and alternative medicine on the quality of life in inflammatory bowel disease: results from a French national survey

BACKGROUND

Complementary and alternative medicines (CAM) are widely used by patients with inflammatory bowel disease (IBD). Few data have been published on the impact of CAM on the quality of life (QOL).

AIMS

The aim of the study was to describe CAM use in French patients with IBD, identify characteristics associated with CAM use, and assess the impact of CAM on the QOL.

METHODS

We conducted an internet survey on CAM through the French IBD patient's association website. Patients had to answer a questionnaire (LimeSurvey application) about sociodemography, IBD treatment, CAM type, socioeconomic data, and QOL using the Short IBD Questionnaire (SIBDQ). Patients noted the impact of CAM on their symptoms and on their QOL on a scale of 0-100. CAM users and nonusers were compared by univariate and multivariate analyses.

RESULTS

A total of 936 IBD patients responded and 767 (82.4%) filled up the whole questionnaire: 503 reported CAM use and 172 had never used. The types of CAM reported were diet-based (30.7%), body-based (25.1%), homeopathic or traditional medicine (19.6%), naturopathy (15.2%), and mind-body medicine (9.1%). The gastroenterologist was aware of CAM use in only 46% of patients. CAM users were more likely to have ulcerative colitis [odds ratio (OR)=1.78, P=0.018], clinical remission (OR=1.42, P=0.06), high level of education (OR=1.51, P=0.02), poor observance (OR=1.81, P=0.017), or to have terminated conventional treatment (OR=2.03, P=0.003). CAM users tend to have higher rates of SIBDQ scores, greater than 50 (OR=1.57, P=0.06). Improvement in symptoms and QOL was reported with all CAM types except mind medicine.

CONCLUSION

CAM use is widespread among IBD patients. CAM users report improvement in symptoms and QOL, but they tend to stop their conventional treatment. Better information about CAM might improve adherence to conventional treatment.

Interactions between the intestinal microbiota and innate lymphoid cells

The mammalian intestine must manage to contain 100 trillion intestinal bacteria without inducing inappropriate immune responses to these microorganisms. The effects of the immune system on intestinal microorganisms are numerous and well-characterized, and recent research has determined that the microbiota influences the intestinal immune system as well. In this review, we first discuss the intestinal immune system and its role in containing and maintaining tolerance to commensal organisms. We next introduce a category of immune cells, the innate lymphoid cells, and describe their classification and function in intestinal immunology. Finally, we discuss the effects of the intestinal microbiota on innate lymphoid cells.

Effect of probiotics on inducing remission and maintaining therapy in ulcerative colitis, Crohn's disease, and pouchitis: meta-analysis of randomized controlled trials

BACKGROUND

Whether probiotics are beneficial at all stages of treatment in inflammatory bowel disease or superior to placebo remains controversial.

METHODS

Two reviewers independently selected randomized controlled trials comparing probiotics with controls in inflammatory bowel disease and extracted data related to remission/response rates, relapse rates, and adverse events. Subanalyses were also performed.

RESULTS

Twenty-three randomized controlled trials with a total of 1763 participants met the inclusion criteria. From the meta-analysis, probiotics significantly increase the remission rates in patients with active ulcerative colitis (UC) (P = 0.01, risk ratio [RR] = 1.51). The remission rates were significantly higher in patients with active UC treated with probiotics than placebo (P < 0.0001, RR = 1.80). Unfortunately, subgroup analysis found that only VSL#3 significantly increased the remission rates compared with controls in patients with active UC (P = 0.004, RR = 1.74). Interestingly, VSL#3 (P < 0.00001, RR = 0.18) also significantly reduced the clinical relapse rates for maintaining remission in patients with pouchitis. No significantly different adverse events were detected between probiotics and controls in the treatment of UC (P = 0.94, RR = 0.99) or CD (P = 0.33, RR = 0.87).

CONCLUSIONS

Administration of probiotics results in additional benefit in inducing remission of patients with UC. VSL#3 are beneficial for maintaining remission in patients with pouchitis. And, probiotics can provide the similar effect as 5-aminosalicylic acid on maintaining remission of UC, although no additional adverse events presented.

The role of probiotics and prebiotics in inducing gut immunity

The gut immune system is influenced by many factors, including dietary components and commensal bacteria. Nutrients that affect gut immunity and strategies that restore a healthy gut microbial community by affecting the microbial composition are being developed as new therapeutic approaches to treat several inflammatory diseases. Although probiotics (live microorganisms) and prebiotics (food components) have shown promise as treatments for several diseases in both clinical and animal studies, an understanding of the molecular mechanisms behind the direct and indirect effects on the gut immune response will facilitate better and possibly more efficient therapy for diseases. In this review, we will first describe the concept of prebiotics, probiotics, and symbiotics and cover the most recently well-established scientific findings regarding the direct and indirect mechanisms by which these dietary approaches can influence gut immunity. Emphasis will be placed on the relationship of diet, the microbiota, and the gut immune system. Second, we will highlight recent results from our group, which suggest a new dietary manipulation that includes the use of nutrient products (organic selenium and Lithothamnium muelleri) and probiotics (Saccharomyces boulardii UFMG 905 and Bifidobacterium sp.) that can stimulate and manipulate the gut immune response, inducing intestinal homeostasis. Furthermore, the purpose of this review is to discuss and translate all of this knowledge into therapeutic strategies and into treatment for extra-intestinal compartment pathologies. We will conclude by discussing perspectives and molecular advances regarding the use of prebiotics or probiotics as new therapeutic strategies that manipulate the microbial composition and the gut immune responses of the host.

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.

Probiotics

Ample research has described multiple biological activities of probiotics in animals and in humans. Probiotics interfere with local and systemic immune reactions and thus exert an influence on the barrier function of the intestinal mucosa. Therefore, attempting inflammatory bowel disease treatment with probiotics seems reasonable. In fact, a growing number of trials have studied the therapeutic effects in ulcerative colitis and Crohn's disease. Promising results have been found and in some, indications such as maintenance of remission of ulcerative colitis and pouchitis guidelines recommend therapy with probiotics already today. However, many open questions still remain and the urgent need for high-quality trials requires much more research in the future.

Novel treatment options for ulcerative colitis

The approved treatment options for patients with ulcerative colitis (UC) are currently limited to mesalamine or immunosuppressants. Patients who do not respond to mesalamine-based therapy can be treated with immunomodulators or anti-TNF antibody therapy. Failure or adverse reactions to these medications leaves the patient with little choice other than colectomy. However, novel insights into the pathogenic drivers of UC have led to new developments in drugs that promise clinical efficacy via modulation of targeted pathways. Given the impending expansion of therapeutic options for patients with UC, clinicians and researchers should be familiar with these mechanisms of action. In addition, the typical 'step-up' treatment paradigm for UC will likely need to be reshaped to allow for a more personalized approach to treating UC.

Review article: the association of diet with onset and relapse in patients with inflammatory bowel disease

BACKGROUND

The role of diet in inflammatory bowel disease (IBD) is supported by migration studies and increasing incidences in line with Westernisation.

AIM

To give a complete overview of studies associating habitual diet with the onset or relapses in ulcerative colitis (UC) or Crohn's disease (CD).

METHODS

A structured search in Pubmed, the Cochrane Library and EMBASE was performed using defined key words, including only full text papers in English language.

RESULTS

Forty-one studies were identified, investigating onset (n = 35), relapses (n = 5) or both (n = 1). Several studies reported high intake of sugar or sugar-containing foods (n = 7 UC, n = 12 CD), and low intake of fruits and/or vegetables (n = 5 UC, n = 10 CD) to be associated with an increased onset risk. However, these findings could not be confirmed by similar or higher numbers of other studies. A possible protective role was found for grain-derived products in CD onset, but results were inconsistent for dietary fibre in UC and CD and grain-derived products in UC. No definite conclusions could be drawn for unsaturated fatty acids (UFA), protein and energy intake due to limited and/or inconsistent results. Six studies reported on diet and relapse risk, of which only two (n = 1 UC, n = 1 CD) had a prospective follow-up.

CONCLUSIONS

The current evidence is not sufficient to draw firm conclusions on the role of specific food components or nutrients in the aetiology of IBD. Furthermore, large prospective studies into the role of habitual diet as a trigger of relapses are needed, to identify new therapeutic or preventive targets.

Lactobacillus acidophilus alleviates platelet-activating factor-induced inflammatory responses in human intestinal epithelial cells

Probiotics have been used as alternative prevention and therapy modalities in intestinal inflammatory disorders including inflammatory bowel diseases (IBD) and necrotizing enterocolitis (NEC). Pathophysiology of IBD and NEC includes the production of diverse lipid mediators, including platelet-activating factor (PAF) that mediate inflammatory responses in the disease. PAF is known to activate NF-κB, however, the mechanisms of PAF-induced inflammation are not fully defined. We have recently described a novel PAF-triggered pathway of NF-κB activation and IL-8 production in intestinal epithelial cells (IECs), requiring the pivotal role of the adaptor protein Bcl10 and its interactions with CARMA3 and MALT1. The current studies examined the potential role of the probiotic Lactobacillus acidophilus in reversing the PAF-induced, Bcl10-dependent NF-κB activation and IL-8 production in IECs. PAF treatment (5 µM×24 h) of NCM460 and Caco-2 cells significantly increased nuclear p65 NF-κB levels and IL-8 secretion (2-3-fold, P<0.05), compared to control, which were blocked by pretreatment of the cells for 6 h with L. acidophilus (LA) or its culture supernatant (CS), followed by continued treatments with PAF for 24 h. LA-CS also attenuated PAF-induced increase in Bcl10 mRNA and protein levels and Bcl10 promoter activity. LA-CS did not alter PAF-induced interaction of Bcl10 with CARMA3, but attenuated Bcl10 interaction with MALT1 and also PAF-induced ubiquitination of IKKγ. Efficacy of bacteria-free CS of LA in counteracting PAF-induced inflammatory cascade suggests that soluble factor(s) in the CS of LA mediate these effects. These results define a novel mechanism by which probiotics counteract PAF-induced inflammation in IECs.

Systematic review: the efficacy of herbal therapy in inflammatory bowel disease

BACKGROUND

Complementary and alternative medicine (CAM), particularly herbal therapy, is widely used by patients with inflammatory bowel disease (IBD) but controlled data are limited.

AIM

To systematically review the literature on the efficacy of herbal therapy in the treatment of ulcerative colitis (UC) and Crohn's disease (CD).

METHODS

Publications in English and non-English literatures (MEDLINE, EMBASE, EBM Reviews, AMED, Global Health) were searched from 1947 to 2013 for controlled clinical studies of herbal therapy in IBD. Outcome measures included response and remission rates.

RESULTS

Twenty-one randomised controlled trials (14 UC; 7 CD) including a total of 1484 subjects (mean age 41, 50% female) were analysed. In UC, aloe vera gel, Triticum aestivum (wheat grass juice), Andrographis paniculata extract (HMPL-004) and topical Xilei-san were superior to placebo in inducing remission or response, and curcumin was superior to placebo in maintaining remission; Boswellia serrata gum resin and Plantago ovata seeds were as effective as mesalazine, whereas Oenothera biennis (evening primrose oil) had similar relapse rates as omega-3 fatty acids in the treatment of UC. In CD, Artemisia absinthium (wormwood) and Tripterygium wilfordii were superior to placebo in inducing remission, and preventing clinical recurrence of post-operative CD respectively.

CONCLUSIONS

Randomised controlled trials of herbal therapy for the treatment of IBD show encouraging results but studies remain limited and heterogenous. Larger controlled studies with stricter endpoints and better-defined patient groups are required to obtain more conclusive results on the use of CAM therapies in IBD.

Relevance of commensal microbiota in the treatment and prevention of inflammatory bowel disease

Commensal microbiota that reside primarily in the gut of mammals influence the hosts' health to a great extent. Shaping of host immunity locally, a vital component of this influence, can have pro-inflammatory, anti-inflammatory, or neutral outcomes, presumably depending on the composition of the microbiota in an individual and type of molecules expressed in the individual members of the microbiota. Thus, these microbial species can be thought of as a reservoir of molecules that can be used to improve or worsen the condition of patients suffering from immunity or inflammation-driven pathologies like inflammatory bowel disease. In the current review, we elaborate, based on the literature available from murine models of disease and clinical case studies, the need to identify individual members of commensal microbiota that can precipitate or resolve inflammatory bowel disease. Therapeutic approaches could entail enrichment of members of microbiota (or molecules from these microbes), which induces expansion or enhancement of function of regulatory T cells or tolerogenic dendritic cells and reduce members that cause inflammation either directly or indirectly by influencing metabolic and other host molecules. Efficiency of bacteria-driven therapy would potentially be enhanced as we refine our approaches from the use of complete feces as done in fecal transplantation to utilization of microbiota-derived molecules as exemplified by the capsular polysaccharide A from the human gut commensal Bacteroides fragilis. We also highlight the advantages and disadvantages of each approach, defining a natural alternative to the current chemical-based immunosuppressive regimen for patients with inflammatory bowel disease.

Pathobiology and potential therapeutic value of intestinal short-chain fatty acids in gut inflammation and obesity

BACKGROUND

The lumen of the gastrointestinal tract contains many substances produced from the breakdown of foodstuffs, from salivary, esophageal, intestinal, hepatic, and pancreatic secretions, and from sloughed cells present in the gastrointestinal lumen. Although these substances were traditionally regarded as waste products, there is increasing realization that many can be biologically active, either as signalling compounds or as nutrients. For example, proteins are broken down into amino acids, which are then sensed by nutrient receptors. The gut microbiome, which is at highest abundance in the ileocecum, has powerful metabolic activity, digesting and breaking down unabsorbed carbohydrates, proteins, and other ingested nutrients into phenols, amines, volatile organic compounds, methane, carbon dioxide, hydrogen, and hydrogen sulfide into volatile fatty acids, also called short-chain fatty acids (SCFAs).

CONCLUSION

These latter substances are the topic of this review. In this review, we will briefly discuss recent advances in the understanding SCFA production, signalling, and absorption, followed by a detailed description and discussion of trials of SCFAs, probiotics, and prebiotics in the treatment of gastrointestinal disease, in particular ulcerative colitis (UC), pouchitis, short bowel syndrome, and obesity.

Probiotic modulation of dendritic cell function is influenced by ageing

Dendritic cells (DCs) are critical for the generation of T-cell responses. DC function may be modulated by probiotics, which confer health benefits in immunocompromised individuals, such as the elderly. This study investigated the effects of four probiotics, Bifidobacterium longum bv. infantis CCUG 52486, B. longum SP 07/3, Lactobacillus rhamnosus GG (L.GG) and L. casei Shirota (LcS), on DC function in an allogeneic mixed leucocyte reaction (MLR) model, using DCs and T-cells from young and older donors in different combinations. All four probiotics enhanced expression of CD40, CD80 and CCR7 on both young and older DCs, but enhanced cytokine production (TGF-β, TNF-α) by old DCs only. LcS induced IL-12 and IFNγ production by DC to a greater degree than other strains, while B. longum bv. infantis CCUG 52486 favoured IL-10 production. Stimulation of young T cells in an allogeneic MLR with DC was enhanced by probiotic pretreatment of old DCs, which demonstrated greater activation (CD25) than untreated controls. However, pretreatment of young or old DCs with LPS or probiotics failed to enhance the proliferation of T-cells derived from older donors. In conclusion, this study demonstrates that ageing increases the responsiveness of DCs to probiotics, but this is not sufficient to overcome the impact of immunosenescence in the MLR.

Mechanisms and effectiveness of prebiotics in modifying the gastrointestinal microbiota for the management of digestive disorders

The gastrointestinal microbiota is a complex ecosystem with each human individual hosting at least 160 different bacterial strains. Our understanding of its role is rapidly expanding as a result of the molecular microbiological techniques that can accurately characterise its composition and 'omics' technologies that measure its metabolic activity. Since 1995, extensive research has investigated the prebiotic concept, which describes how supplementation of some non-digestible oligosaccharides can stimulate the growth and/or activity of specific genera including bifidobacteria. However, the vast majority of studies are in healthy human subjects, with few undertaken in patients with disorders relevant to clinical nutrition. Marked alterations of the luminal microbiota have been demonstrated in patients with digestive disorders, highlighting mechanisms through which they might be involved in their pathogenesis, including higher clostridia in patients who develop diarrhoea during enteral nutrition and the influence of bifidobacteria on intestinal dendritic cell phenotype in Crohn's disease. The impact of prebiotics on the intestinal microbiota of healthy people has not been consistently replicated in patients with digestive disorders. For example, a number of studies show that inulin/oligofructose do not increase bifidobacteria in enteral nutrition and Crohn's disease. Indeed, in Crohn's disease and irritable bowel syndrome there is evidence that some prebiotics in high doses worsen functional symptoms. Unlike healthy human subjects, patients experience a number of issues that may alter their gastrointestinal microbiota (disease, antibiotics and inflammation) and the use of microbiota modifying therapies, such as prebiotics, do not always elicit the same effects in patients as they do in healthy people.

Probiotics in the management of irritable bowel syndrome and inflammatory bowel disease

PURPOSE OF REVIEW

There is direct evidence that the pathogenesis of inflammatory bowel disease (IBD) involves the gastrointestinal microbiota and some evidence that the microbiota might also play a similar role in irritable bowel syndrome (IBS). The aim of this article is to review the emerging evidence for the mechanisms and effectiveness of probiotics in the management of these disorders.

RECENT FINDINGS

The composition of the gastrointestinal microbiota is strongly influenced by factors including age, diet and disease. Probiotics may be effective through their impact on the host gastrointestinal microbiota and promotion of mucosal immunoregulation. Probiotics are considered to be well tolerated, although the quality of studies and health claims has been variable. There are many short-term studies demonstrating the effectiveness of probiotics in IBS, although recommendations should be made for specific strains and for specific symptoms. Within IBD, a number of trials have shown the benefits of a range of probiotics in pouchitis and in ulcerative colitis, although current evidence in Crohn's disease is less promising.

SUMMARY

Clearly, some probiotics have considerable potential in the management of IBS and IBD; however, the benefits are strain specific. High-quality trials of probiotics in gastrointestinal disorders as well as laboratory investigations of their mechanism of action are required in order to understand who responds and why.

Influence of fermented milk products, prebiotics and probiotics on microbiota composition and health

The gut microbiota is a highly diverse and relative stabile ecosystem increasingly recognized for its impact on human health. The homeostasis of microbes and the host is also referred to as eubiosis. In contrast, deviation from the normal composition, defined as dysbiosis, is often associated with localized diseases such as inflammatory bowel disease or colonic cancer, but also with systemic diseases like metabolic syndrome and allergic diseases. Modulating a gut microbiota dysbiosis with nutritional concepts may contribute to improving health status, reducing diseases or disease symptoms or supporting already established treatments. The gut microbiota can be modulated by different nutritional concepts, varying from specific food ingredients to complex diets or by the ingestion of particular live microorganisms. To underpin the importance of bacteria in the gut, we describe molecular mechanisms involved in the crosstalk between gut bacteria and the human host, and review the impact of different nutritional concepts such as pre-, pro- and synbiotics on the gastrointestinal ecosystem and their potential health benefits. The aim of this review is to provide examples of potential nutritional concepts that target the gut microbiota to support human physiology and potentially health outcomes.

The hookworm pharmacopoeia for inflammatory diseases

In the developed world, declining prevalence of parasitic infections correlates with increased incidence of allergic and autoimmune disorders. Current treatments for these chronic inflammatory conditions have little to no effect on their prevalence and are referred to as "controllers" rather than cures. There has been limited success in therapeutically targeting allergic and autoimmune pathways, leaving an unmet need for development of effective anti-inflammatories. We discuss the benefit of hookworm infections and the parasite's ability to condition the immune system to prevent allergic asthma and inflammatory bowel diseases. We then examine the immunomodulatory properties of selected hookworm-derived proteins in these two models of inflammation. While hookworm protein therapy has yet to be fully exploited, the identification of these proteins and the mechanisms by which they skew the immune system will provide new avenues for controlling and optimally reversing key pathological processes important in allergic and inflammatory bowel diseases.

Indian Society of Gastroenterology consensus on ulcerative colitis

In 2010, the Indian Society of Gastroenterology's Task Force on Inflammatory Bowel Diseases undertook an exercise to produce consensus statements on ulcerative colitis. This consensus, produced through a modified Delphi process, reflects our current understanding of the definition, diagnostic work up, treatment and complications of ulcerative colitis. The consensus statements are intended to serve as a reference point for teaching, clinical practice, and research in India.

Amelioration of dextran sodium sulfate-induced colitis in mice by Rhodobacter sphaeroides extract

Bacteria can produce some compounds in response to their environment. These compounds are widely used in cosmetic and pharmaceutical applications. Some probiotics have immunomodulatory activities and modulate the symptoms of several diseases. Autoimmune diseases represent a complex group of conditions that are thought to be mediated through the development of autoreactive immunoresponses. Inflammatory bowel disease (IBD) is common autoimmune disease that affects many individuals worldwide. Previously, we found that the extracts of Rhodobacter sphaeroides (Lycogen) inhibited nitric oxide production and inducible nitric-oxide synthase expression in activated macrophages. In this study, the effect of Lycogen™, a potent anti-inflammatory agent, was evaluated in mice with dextran sodium sulfate (DSS)-induced colitis. Oral administration of Lycogen™ reduced the expressions of proinflammatory cytokines (tumor necrosis factor-α and interleukin-1β) in female BABL/c mice. In addition, the increased number of bacterial flora in the colon induced by DSS was amelirated by Lycogen™. The histological score of intestinal inflammation in 5% DSS-treated mice after oral administration of Lycogen™ was lower than that of control mice. Meanwhile, Lycogen™ dramatically prolonged the survival of mice with severe colitis. These findings identified that Lycogen™ is an anti-inflammatory agent with the capacity to ameliorate DSS-induced colitis.

Biodiversity and functional genomics in the human microbiome

Over the course of our lives, humans are colonized by a tremendous diversity of commensal microbes, which comprise the human microbiome. The collective genetic potential (metagenome) of the human microbiome is orders of magnitude more than the human genome, and it profoundly affects human health and disease in ways we are only beginning to understand. Advances in computing and high-throughput sequencing have enabled population-level surveys such as MetaHIT and the recently released Human Microbiome Project, detailed investigations of the microbiome in human disease, and mechanistic studies employing gnotobiotic model organisms. The resulting knowledge of human microbiome composition, function, and range of variation across multiple body sites has begun to assemble a rich picture of commensal host-microbe and microbe-microbe interactions as well as their roles in human health and disease and their potential as diagnostic and therapeutic tools.

Microbial regulation of allergic responses to food

The incidence of food allergy in developed countries is rising at a rate that cannot be attributed to genetic variation alone. In this review, we discuss the environmental factors that may contribute to the increasing prevalence of potentially fatal anaphylactic responses to food. Decreased exposure to enteric infections due to advances in vaccination and sanitation, along with the adoption of high-fat (Western) diets, antibiotic use, Cesarean birth, and formula feeding of infants, have all been implicated in altering the enteric microbiome away from its ancestral state. This collection of resident commensal microbes performs many important physiological functions and plays a central role in the development of the immune system. We hypothesize that alterations in the microbiome interfere with immune system maturation, resulting in impairment of IgA production, reduced abundance of regulatory T cells, and Th2-skewing of baseline immune responses which drive aberrant responses to innocuous (food) antigens.