Use of probiotics in the treatment of inflammatory bowel disease

Microbial Modulation in Inflammatory Bowel Diseases

Gut dysbiosis is one of prominent features in inflammatory bowel diseases (IBDs) which are of an unknown etiology. Although the cause-and-effect relationship between IBD and gut dysbiosis remains to be elucidated, one area of research has focused on the management of IBD by modulating and correcting gut dysbiosis. The use of antibiotics, probiotics either with or without prebiotics, and fecal microbiota transplantation from healthy donors are representative methods for modulating the intestinal microbiota ecosystem. The gut microbiota is not a simple assembly of bacteria, fungi, and viruses, but a complex organ-like community system composed of numerous kinds of microorganisms. Thus, studies on specific changes in the gut microbiota depending on which treatment option is applied are very limited. Here, we review previous studies on microbial modulation as a therapeutic option for IBD and its significance in the pathogenesis of IBD.

Unraveling enterohemorrhagic Escherichia coli infection: the promising role of dietary compounds and probiotics in bacterial elimination and host innate immunity boosting

The innate immune system has developed sophisticated strategies to defense against infections. Host cells utilize the recognition machineries such as toll-like receptors and nucleotide binding and oligomerization domain-like receptors to identify the pathogens and alert immune system. However, some pathogens have developed tactics to evade host defenses, including manipulation of host inflammatory response, interference with cell death pathway, and highjack of phagocytosis signaling for a better survival and colonization in host. Enterohemorrhagic Escherichia coli (EHEC) is a notorious foodborne pathogen that causes severe tissue damages and gastrointestinal diseases, which has been reported to disturb host immune responses. Diverse bioactive compounds such as flavonoids, phenolic acids, alkaloids, saccharides, and terpenoids derived from food varieties and probiotics have been discovered and investigated for their capability of combating bacterial infections. Some of them serve as novel antimicrobial agents and act as immune boosters that harness host immune system. In this review, we will discuss how EHEC, specifically E. coli O157:H7, hijacks the host immune system and interferes with host signaling pathway; and highlight the promising role of food-derived bioactive compounds and probiotics in harnessing host innate immunity and eliminating E. coli O157:H7 infection with multiple strategies.

Postbiotic-Enabled Targeting of the Host-Microbiota-Pathogen Interface: Hints of Antibiotic Decline?

Mismanagement of bacterial infection therapies has undermined the reliability and efficacy of antibiotic treatments, producing a profound crisis of the antibiotic drug market. It is by now clear that tackling deadly infections demands novel strategies not only based on the mere toxicity of anti-infective compounds. Host-directed therapies have been the first example as novel treatments with alternate success. Nevertheless, recent advances in the human microbiome research have provided evidence that compounds produced by the microbial metabolism, namely postbiotics, can have significant impact on human health. Such compounds target the host-microbe-pathogen interface rescuing biotic and immune unbalances as well as inflammation, thus providing novel therapeutic opportunities. This work discusses critically, through literature review and personal contributions, these novel nonantibiotic treatment strategies for infectious disease management and resistance prevention, which could represent a paradigm change rocking the foundation of current antibiotic therapy tenets.

Effect of combined consumption of Lactobacillus brevis KB290 and β-carotene on minor diarrhoea-predominant irritable bowel syndrome-like symptoms in healthy subjects: a randomised, double-blind, placebo-controlled, parallel-group trial

People with non-pathological diarrhoea-predominant irritable bowel syndrome (IBS-D)-like symptoms are present at a significant level even in healthy populations, but established prophylaxis is lacking. Previously, we have found that co-administration of Lactobacillus brevis KB290 (KB290) and β-carotene (βC) attenuated murine colitis (potential cause of IBS-D-like symptoms) significantly. Here, we investigated the effect of KB290 and βC on minor IBS-D-like symptoms in healthy volunteers. After a 4-week run-in period, subjects received a KB290 + βC or placebo capsule for 12 weeks, followed by a 4-week washout period. The KB290 + βC group showed a significant improvement in intensity of abdominal pain and stool frequency compared with the placebo group. The KB290 + βC group showed a significantly higher serum concentration of anti-inflammatory cytokine, interleukin-10, compared with the placebo group. In conclusion, we demonstrated that consumption of KB290 + βC improves minor IBS-D-like symptoms and inflammatory status in healthy volunteers. (UMIN000018002).

Sulphate-reducing bacteria from ulcerative colitis patients induce apoptosis of gastrointestinal epithelial cells

The human microbiome consists of a multitude of bacterial genera and species which continuously interact with one another and their host establishing a metabolic equilibrium. The dysbiosis can lead to the development of pathology, such as inflammatory bowel diseases. Sulfide-producing prokaryotes, including sulphate-reducing bacteria (SRB) constituting different genera, including the Desulfovibrio, are commonly detected within the human microbiome recovered from fecal material or colonic biopsy samples. It has been proposed that SRB likely contribute to colonic pathology, for example ulcerative colitis (UC). The interaction of SRB with the human colon and intestinal epithelial cell lines has been investigated using Desulfovibrio indonesiensis as a model mono-culture and in a co-culture with E. coli isolate, and with SRB consortia from human biopsy samples. We find that D. indonesiensis, whether as a mono- or co-culture, was internalized and induced apoptosis in colon epithelial cells. This effect was enhanced in the presence of E. coli. The SRB combination obtained through enrichment of biopsies from UC patients induced apoptosis of a human intestinal epithelial cell line. This response was not observed in SRB enrichments from healthy (non-UC) controls. Importantly, apoptosis was detected in epithelial cells from UC patients and was not seen in epithelial cells of healthy donors. Furthermore, the antibody raised against exopolysaccharides (EPS) of D. indonesiensis cross reacted with the SRB population from UC patients but not with the SRB combination from non-UC controls. This study reinforces a correlation between the presence of sulphate-reducing bacteria and an inflammatory response in UC sufferers.

Clinical Uses of Probiotics

Probiotics are live nonpathogenic microorganisms. Many of these microorganisms are part of the normal human gut flora, where they live in a symbiotic relationship. Probiotics have been used to treat gastrointestinal (GI) and non-GI medical conditions. However, the data supporting their use are often conflicting, especially for non-GI-associated illnesses. The strongest evidence supporting the use of probiotics is related to the treatment of acute diarrhea and pouchitis. Atopic eczema in children and genitourinary infections are the only non-GI-related medical conditions where probiotics may have some beneficial effects. Product selection and dosing are not the same in all conditions, and the beneficial effects of each probiotic strain cannot be generalized.The purpose of this article is to provide most recent information about probiotics and its uses. In contrast with previously published reviews on probiotics, we also discuss the composition of various products (Table 1), indications for their use (Table 2), product selection, and dosing of probiotics.Probiotics are safe and appear to exert some beneficial effects in GI-related illnesses. The use of probiotics in non-GI illnesses is not sufficiently supported by current data.

The anti-inflammatory effects of a high-frequency oligodeoxynucleotide from the genomic DNA of Lactobacillus casei

Genomic DNA has been identified as an anti-inflammatory component of Lactobacillus species, the effects of which are mediated through toll-like receptor (TLR) 9. In this study, we identified 14 novel anti-inflammatory oligodeoxynucleotide (ODN) from the genomic DNA of Lactobacillus casei by measuring their effects on the secretion of interleukin (IL)-8 (CXCL8) in the human epithelial colorectal adenocarcinoma cell line Caco-2 cells. The ODN TTTTGCCG strongly decreased IL-8 secretion. In the genomic DNA of Lactobacillus species, the frequency of TTTTGCCG was highest in the genomic DNA of L. casei and similar among strains of L. casei. Decreases in inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2 expressions in macrophage-like differentiated THP-1 cells confirmed the anti-inflammatory effect of TTTTGCCG. Furthermore, oral administration of TTTTGCCG ameliorated dextran sodium sulfate (DSS)-induced murine colitis and DSS-induced increased expression of inflammatory factor mRNAs, such as macrophage inflammatory protein (MIP)-2 (CXCL2), iNOS, and COX-2. The anti-inflammatory effect of TTTTGCCG was mainly regulated by an increase in heat shock protein (Hsp) 70 expression in the epithelium. TLR9 and Hsp90 may primarily mediate the anti-inflammatory effect of TTTTGCCG on Hsp70 signaling.

Microbiota and radiation-induced bowel toxicity: lessons from inflammatory bowel disease for the radiation oncologist

New gastrointestinal symptoms are frequent after pelvic radiotherapy and can greatly affect the quality of life of cancer survivors. The effect of radiation on the intestinal microbiota, and the clinical implications of a modified microbial balance after radiotherapy are now beginning to emerge. In this Personal View, we show the importance of the microbiota for intestinal homoeostasis, and discuss the similarity between inflammatory bowel disease, which has been extensively researched, and radiation-induced gastrointestinal toxicity. By use of microbiota profiles for risk assessment and manipulation of the intestinal flora for prevention and treatment of radiation, enteropathy could become a reality and would be of substantial relevance to the increasing numbers of long-term cancer survivors.

Differences in TLR9-dependent inhibitory effects of H(2)O(2)-induced IL-8 secretion and NF-kappa B/I kappa B-alpha system activation by genomic DNA from five Lactobacillus species

Lactic acid bacteria (LAB) show anti-inflammatory effects, and their genomic DNA was identified as one of the anti-inflammatory components. Despite the differences in anti-inflammatory effects between live LAB dependent not only on genus but also species, this effect has not been compared at the genomic DNA level. We compared the anti-inflammatory effects of the genomic DNA from five Lactobacillus species-Lactobacillus acidophilus, Lactobacillus casei, Lactobacillus gasseri, Lactobacillus plantarum, and Lactobacillus reuteri-using Caco-2 cells. To evaluate anti-inflammatory effects, decreases in H(2)O(2)-induced IL-8 secretion and inhibition of H(2)O(2)-induced NF-κB/IκB-α system activation were examined. All LAB genomic DNAs dose-dependently decreased H(2)O(2)-induced IL-8 secretion and inhibited H(2)O(2)-induced NF-κB/IκB-α system activation. Comparison of these effects between Lactobacillus species showed that the anti-inflammatory effects of L. acidophilus genomic DNA are lower than those of the other species. Furthermore, suppression of Toll-like receptor 9 (TLR9), a specific receptor of bacterial DNA, expression by RNAi abolished the decrease of H(2)O(2)-induced IL-8 secretion and inhibition of H(2)O(2)-induced NF-κB/IκB-α system activation by LAB genomic DNA. Our results demonstrated that the anti-inflammatory effects of genomic DNA differ between Lactobacillus species and TLR9 is one of the major pathways responsible for the anti-inflammatory effect of LAB genomic DNA.

Probiotic Bifidobacterium breve induces IL-10-producing Tr1 cells in the colon

Specific intestinal microbiota has been shown to induce Foxp3(+) regulatory T cell development. However, it remains unclear how development of another regulatory T cell subset, Tr1 cells, is regulated in the intestine. Here, we analyzed the role of two probiotic strains of intestinal bacteria, Lactobacillus casei and Bifidobacterium breve in T cell development in the intestine. B. breve, but not L. casei, induced development of IL-10-producing Tr1 cells that express cMaf, IL-21, and Ahr in the large intestine. Intestinal CD103(+) dendritic cells (DCs) mediated B. breve-induced development of IL-10-producing T cells. CD103(+) DCs from Il10(-/-), Tlr2(-/-), and Myd88(-/-) mice showed defective B. breve-induced Tr1 cell development. B. breve-treated CD103(+) DCs failed to induce IL-10 production from co-cultured Il27ra(-/-) T cells. B. breve treatment of Tlr2(-/-) mice did not increase IL-10-producing T cells in the colonic lamina propria. Thus, B. breve activates intestinal CD103(+) DCs to produce IL-10 and IL-27 via the TLR2/MyD88 pathway thereby inducing IL-10-producing Tr1 cells in the large intestine. Oral B. breve administration ameliorated colitis in immunocompromised mice given naïve CD4(+) T cells from wild-type mice, but not Il10(-/-) mice. These findings demonstrate that B. breve prevents intestinal inflammation through the induction of intestinal IL-10-producing Tr1 cells.

A meta-analysis of probiotic efficacy for gastrointestinal diseases

Background

Meta-analyses on the effects of probiotics on specific gastrointestinal diseases have generally shown positive effects on disease prevention and treatment; however, the relative efficacy of probiotic use for treatment and prevention across different gastrointestinal diseases, with differing etiology and mechanisms of action, has not been addressed.

Methods/Principal Findings

We included randomized controlled trials in humans that used a specified probiotic in the treatment or prevention of Pouchitis, Infectious diarrhea, Irritable Bowel Syndrome, Helicobacter pylori, Clostridium difficile Disease, Antibiotic Associated Diarrhea, Traveler's Diarrhea, or Necrotizing Enterocolitis. Random effects models were used to evaluate efficacy as pooled relative risks across the eight diseases as well as across probiotic species, single vs. multiple species, patient ages, dosages, and length of treatment. Probiotics had a positive significant effect across all eight gastrointestinal diseases with a relative risk of 0.58 (95% (CI) 0.51–0.65). Six of the eight diseases: Pouchitis, Infectious diarrhea, Irritable Bowel Syndrome, Helicobacter pylori, Clostridium difficile Disease, and Antibiotic Associated Diarrhea, showed positive significant effects. Traveler's Diarrhea and Necrotizing Enterocolitis did not show significant effects of probiotcs. Of the 11 species and species mixtures, all showed positive significant effects except for Lactobacillus acidophilus, Lactobacillus plantarum, and Bifidobacterium infantis. Across all diseases and probiotic species, positive significant effects of probiotics were observed for all age groups, single vs. multiple species, and treatment lengths.

Conclusions/Significance

Probiotics are generally beneficial in treatment and prevention of gastrointestinal diseases. Efficacy was not observed for Traveler's Diarrhea or Necrotizing Enterocolitis or for the probiotic species L. acidophilus, L. plantarum, and B. infantis. When choosing to use probiotics in the treatment or prevention of gastrointestinal disease, the type of disease and probiotic species (strain) are the most important factors to take into consideration.

Toll-like receptor 2 monoclonal antibody or/and Toll-like receptor 4 monoclonal antibody increase counts of Lactobacilli and Bifidobacteria in dextran sulfate sodium-induced colitis in mice

BACKGROUND AND AIM

The accurate pathogenesis of ulcerative colitis (UC) is not yet well understood. Recently, Toll-like receptor 2 (TLR2), TLR4 and gut microbial flora have been proved as playing important roles in the process of UC. This study was to evaluate the effect of TLR2 and TLR4 monoclonal antibodies on gut microbial flora in dextran sulfate sodium (DSS)-induced colitis in a mouse model.

METHODS

We evaluated the effects of the TLR2 and TLR4 monoclonal antibodies on the development of DSS-induced colitis. Clinical symptoms were evaluated by the disease activity index (DAI), while tissue samples were evaluated by histological scoring (HS). Meanwhile, the mucosal mRNA expressions of TLR2, TLR4, interferon-γ (IFN-γ), interleukin-4 (IL-4) and IL-17 were analyzed by Realtime polymerase chain reaction (PCR). The mucosal protein TRAF6, TAB1, P-IKK, P-P38α mitogen-activated protein kinase (MAPL) and c-jun expressions of the TLR2 and TLR4 signaling pathways were analyzed using Western blot. The mucosal nuclear factor kappa B (NF-κB) was analyzed using electrophoretic mobility shift assay. Fecal samples were obtained directly from the cecum for microbiological studies.

RESULTS

Expressions of TLR2 and TLR4 in colonic epithelial cells on DSS-induced colitis were much higher than normal ones. After the treatment with TLR2mAb and TLR4mAb, DAI and HS were decreased significantly. The UC model group showed a conspicuous increase of Escherichia coli and decreases of Lactobacillus spp. and Bifidobacterium spp. After being treated with TLR2mAb or/and TLR4mAb, Lactobacillus spp. and Bifidobacterium spp. increased to the normal level.

CONCLUSIONS

TLR2mAb and TLR4mAb can suppress the development of DSS-induced colitis and increase counts of Lactobacilli and Bifidobacteria.

Enteric commensal bacteria induce extracellular signal-regulated kinase pathway signaling via formyl peptide receptor-dependent redox modulation of dual specific phosphatase 3

The normal microbial occupants of the mammalian intestine are crucial for maintaining gut homeostasis, yet the mechanisms by which intestinal cells perceive and respond to the microbiota are largely unknown. Intestinal epithelial contact with commensal bacteria and/or their products has been shown to activate noninflammatory signaling pathways, such as extracellular signal-related kinase (ERK), thus influencing homeostatic processes. We previously demonstrated that commensal bacteria stimulate ERK pathway activity via interaction with formyl peptide receptors (FPRs). In the current study, we expand on these findings and show that commensal bacteria initiate ERK signaling through rapid FPR-dependent reactive oxygen species (ROS) generation and subsequent modulation of MAP kinase phosphatase redox status. ROS generation induced by the commensal bacteria Lactobacillus rhamnosus GG and the FPR peptide ligand, N-formyl-Met-Leu-Phe, was abolished in the presence of selective inhibitors for G protein-coupled signaling and FPR ligand interaction. In addition, pretreatment of cells with inhibitors of ROS generation attenuated commensal bacteria-induced ERK signaling, indicating that ROS generation is required for ERK pathway activation. Bacterial colonization also led to oxidative inactivation of the redox-sensitive and ERK-specific phosphatase, DUSP3/VHR, and consequent stimulation of ERK pathway signaling. Together, these data demonstrate that commensal bacteria and their products activate ROS signaling in an FPR-dependent manner and define a mechanism by which cellular ROS influences the ERK pathway through a redox-sensitive regulatory circuit.

Review article: faecal transplantation therapy for gastrointestinal disease

BACKGROUND

Evidence is emerging regarding the relationship between a dysbiosis of the human gut microbiota and a number of gastrointestinal diseases as well as diseases beyond the gut. Probiotics have been investigated in many gastrointestinal disease states, with variable and often modest outcomes. Faecal transplantation is an alternative approach to manipulate the gut microbiota.

AIM

To review the use of faecal transplantation therapy for the management of gastrointestinal disorders.

METHODS

Available articles on faecal transplantation in the management of gastrointestinal disorders were identified using a Pubmed search and bibliographies of review articles on the subject were collated.

RESULTS

A total of 239 patients who had undergone faecal transplantation were reported. Seventeen of 22 studies of faecal transplantation were in fulminant or refractory Clostridium difficile. Studies of faecal transplantation are heterogeneous regarding the patients, donors, screening, methods of administration and definition of response. Faecal transplantation for C. difficile has been demonstrated to be effective in 145/166 (87%) patients. Small numbers of patients are reported to have undergone successful faecal transplantation for irritable bowel syndrome and inflammatory bowel disease.

CONCLUSIONS

Faecal transplantation has been reported with good outcomes for fulminant and refractory C. difficile. No adverse effects of faecal transplantation have been reported. However, there are no level 1 data of faecal transplantation and reports to date may suffer from reporting bias of positive outcomes and under-reporting of adverse effects. This therapy holds great promise, where a dysbiosis of the gut microbiota is responsible for disease and further studies are necessary to explore this potential.

Cellular and molecular mechanisms in the two major forms of inflammatory bowel disease

The factors involved in the pathogenesis of Crohn's disease and ulcerative colitis, the two major types of inflammatory bowel disease (IBD) are summarized. Intestinal antigens composed of bacterial flora along with antigen presentation and impaired mucosal barrier have an important role in the initiation of IBD. The bacterial community may be modified by the use of antibiotics and probiotics. The dentritic cells recognize the antigens by cell surface Toll like receptor and the cytoplasmic CARD/NOD system. The balance between Th1/Th2/Th17 cell populations being the source of a variety of cytokines regulates the inflammatory mechanisms and the clearance of microbes. The intracellular killing and digestion, including autophagy, are important in the protection against microbes and their toxins. The homing process determines the location and distribution of the immune cells along the gut. All these players are potential targets of pharmacological manipulation of disease status.

The intestinal microbiota in health and disease: the influence of microbial products on immune cell homeostasis

PURPOSE OF REVIEW

A vast and diverse array of microbes colonizes the mammalian gastrointestinal tract. These microorganisms are integral in shaping the development and function of the immune system. Metagenomic sequencing analysis has revealed alterations in intestinal microbiota in patients suffering from chronic inflammatory diseases, including inflammatory bowel disease and asthma. This review will discuss the mechanisms through which the innate immune system recognizes and responds to the intestinal microbiota as well as the effect of specific microbiota-derived signals on immune cell homeostasis.

RECENT FINDINGS

Recent studies in murine model systems have demonstrated that manipulation of the intestinal microbiota can alter mammalian immune cell homeostasis. Specific microbial signals have been identified that can impact immune cell function both within the intestinal tract and in peripheral tissues. These microbiota-derived signals can either have an immunoregulatory effect, creating an immune state that is refractory to inflammation, or conversely, act as an adjuvant, aiding in the propagation of an immune response.

SUMMARY

Associations between alterations in the microbiota and human disease implicate intestinal microbial signals in shaping immune responses. These signals are recognized by innate immune cells and influence the ability of these cells to modulate both the local and systemic immune response.

Prevention of TNBS-induced colitis by different Lactobacillus and Bifidobacterium strains is associated with an expansion of gammadeltaT and regulatory T cells of intestinal intraepithelial lymphocytes

BACKGROUND

Probiotics may protect against inflammatory bowel disease through regulation of lamina propria lymphocytes (LPLs) function. Data are lacking on possible involvement of intraepithelial lymphocytes (IELs). The aim of this study was to investigate whether different probiotic mixtures prevented gut inflammatory disease and the role of both IELs and LPLs.

METHODS

BALB/c mice received 2 probiotic mixtures orally for 3 weeks, as Mix1 (Lactobacillus acidophilus and Bifidobacterium longum), or Mix2 (Lactobacillus plantarum, Streptococcus thermophilus, and Bifidobacterium animalis subsp. lactis). Colitis was induced by intrarectal administration of trinitrobenzene sulfonic acid (TNBS). Probiotics in stools were analyzed by real-time polymerase chain reaction (PCR). Colon subpopulations of IELs and LPLs were assayed by flow cytometry. Serum cytokines were measured by cytometric bead array (CBA).

RESULTS

All probiotics colonized the intestine. The 2 mixtures prevented the TNBS-induced intestinal damage, and Mix1 was the most effective. The Mix1 protection was associated with a reduction in CD4(+) cells of IELs and LPLs, an increase in gammadeltaT cells of IELs, and a decrease in gammadeltaT cells of LPLs. An expansion of T regulatory (Treg) cells of IELs was induced by Mix1 and Mix2. Both probiotic mixtures inhibited tumor necrosis factor (TNF)-alpha and monocyte chemotactic protein (MCP)-1 production and upregulated interleukin (IL)-10. In addition, Mix1 prevented the TNBS-induced increase of IL-12 and interferon (IFN)-gamma.

CONCLUSIONS

The 2 probiotic mixtures were able to prevent the TNBS-induced colitis; the L. acidophilus and B. longum mixture was the most effective. Other than an involvement of LPLs, our results report a novel importance of the IELs population in probiotic protection.

In vitroActivation of Mononuclear Cells by Two Probiotics:Lactobacillus paracaseiI 1688,Lactobacillus salivariusI 1794, and their Mixture (PSMIX)

BACKGROUND

Most studies on probiotics have described their effects on the human immune system after ingestion of LAB, but little is known about their effect on in vitro stimulation of human immune cells.

AIM OF THE STUDY

Evaluate the "in vitro" activity of Lactobacillus paracasei (I 1688), Lactobacillus salivarius (I 1794), and a commercial mix of the two (PSMIX, Proge Farm), on immune cells from healthy individuals.

MATERIALS

Two probiotic strains, Lactobacillus salivarius (I 1794; Proge Farm, Italy) and Lactobacillus paracasei (I 1688; Proge Farm, Italy), which are contained in the functional food ENTEROBACILLI, were evaluated for their ability to stimulate peripheral blood mononuclear cells and modulate surface phenotype and cytokine production.

RESULTS

All subjects responded to the bacteria, with different levels of response. The cell populations that showed a significant percent increase were CD4+/CD25+ cells (T-helper activated regulatory cells), CD8+/CD25+ (T-suppressor/cytotoxic activated cells), and CD16+/CD56+ (NK cells) (p<0.05). IL-12 and IFN-gamma in vitro production significantly increased with exposure to probiotics (p<0.05 for both).

CONCLUSIONS

This study provides the first evidence that Lactobacillus paracasei and Lactobacillus salivarius are capable of inducing a specific immune response that may be useful in the clinical setting for improving innate and adaptive immune responses.

The role of probiotics and antibiotics in regulating mucosal inflammation

Antibiotic and probiotic agents have increasingly moved in the focus of basic and clinical research as well as clinical trials for IBD therapy. Both approaches modulate the intestinal flora, the former through eradication or reduction, the latter through establishment or increase of luminal bacteria. Although clinical trials provide proof of principle that both approaches can be therapeutically successfull, we just start to understand the mechanims and may get a first feeling for the potential and limitations of these "microbial" therapies. As basic research sets out to dissect the field using extensive efforts and new technologies, a more detailed exploration of the genetic, immune and microbial factors that govern the life-long crosstalk between host and intestinal flora is already opening new insight into general aspects of human immunology, immune regulation, IBD pathogenesis and therapy.

Mechanisms of action of probiotics: recent advances

The intestinal microbiota plays a fundamental role in maintaining immune homeostasis. In controlled clinical trials probiotic bacteria have demonstrated a benefit in treating gastrointestinal diseases, including infectious diarrhea in children, recurrent Clostridium difficile-induced infection, and some inflammatory bowel diseases. This evidence has led to the proof of principle that probiotic bacteria can be used as a therapeutic strategy to ameliorate human diseases. The precise mechanisms influencing the crosstalk between the microbe and the host remain unclear but there is growing evidence to suggest that the functioning of the immune system at both a systemic and a mucosal level can be modulated by bacteria in the gut. Recent compelling evidence has demonstrated that manipulating the microbiota can influence the host. Several new mechanisms by which probiotics exert their beneficial effects have been identified and it is now clear that significant differences exist between different probiotic bacterial species and strains; organisms need to be selected in a more rational manner to treat disease. Mechanisms contributing to altered immune function in vivo induced by probiotic bacteria may include modulation of the microbiota itself, improved barrier function with consequent reduction in immune exposure to microbiota, and direct effects of bacteria on different epithelial and immune cell types. These effects are discussed with an emphasis on those organisms that have been used to treat human inflammatory bowel diseases in controlled clinical trials.

Effects of monocolonization with Escherichia coli strains O6K13 and Nissle 1917 on the development of experimentally induced acute and chronic intestinal inflammation in germ-free immunocompetent and immunodeficient mice

Germ-free immunocompetent (BALB/c) and immunodeficient (SCID) mice were colonized either by E. coli O6K13 or by E. coli strain Nissle 1917 and intestinal inflammation was induced by administering 2.5% dextran sulfate sodium (DSS) in drinking water. Controls were germ-free mice which demonstrated only mild inflammatory changes after induction of an acute intestinal inflammation with DSS as compared with conventional mice in which acute colitis of the colon mucosa similar to human ulcerative colitis is elicited. In mice monocolonized with the nonpathogenic E. coli Nissle 1917 the inflammatory disease did not develop (damage grade 0) while animals monocolonized with uropathogenic E. coli O6K13 exhibited inflammatory changes similar to those elicited in conventionally reared mice (damage grade 3). In the chronic inflammation model, immunocompetent BALB/c mice monocolonized with E. coli Nissle 1917 showed no conspicuous inflammatory changes of the colon mucosa whereas those monocolonized with E. coli O6K13 developed colon inflammation associated with marked infiltration of inflammatory cells. In contrast to germ-free immunodeficient SCID mice that died after application of DSS, the colon mucosa of SCID mice monoassociated with E. coli Nissle 1917 exhibited only moderate inflammatory changes which were less pronounced than changes of colon mucosa of SCID mice monoassociated with E. coli O6K13.

Effects of Lactobacillus rhamnosus GG on the cell growth and polyamine metabolism in HGC-27 human gastric cancer cells

Previous in vivo studies have suggested that lactobacilli can exert anti-proliferative effects on the gastric epithelium. However, few data are available on their mechanisms of action. The aim of this study was to investigate the effects of increasing concentrations of Lactobacillus rhamnosus strain GG (L. GG) homogenate on cell growth and proliferation [by 3-(4,5 di-methylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, [(3)H]-thymidine incorporation and polyamine biosynthesis] and apoptosis processes (by Bax/Bcl-2 mRNA expression) in HGC-27 human gastric cancer cells. To verify which bacterial fraction was involved in the antiproliferative and proapoptotic effects, the cytoplasm and cell wall extracts were tested separately. HGC-27 cells were sensitive to the apoptotic induction and growth inhibition by increased concentrations of bacterial homogenate. HGC-27 cells were resistant to the bacterial cell wall fractions, whereas increasing cytoplasm fraction concentrations induced evident antiproliferative and proapoptotic actions. These data suggest that cytoplasm extracts could be responsible for L. GG action on HGC-27 cell proliferation.

Helminth infection enhances disease in a murine TH2 model of colitis

BACKGROUND & AIMS

There is convincing evidence from animal and human studies that infection with parasitic helminths can alleviate the histopathology and symptoms of colitis. Here the ability of the rat tapeworm Hymenolepis diminuta to affect the course of oxazolone-induced colitis (a TH2 model) was assessed.

METHODS

Mice were infected with H diminuta and 8 days later they received oxazolone (3 mg in 50% EtOH, intrarectal). On autopsy (3 or 7 days postoxazolone), disease severity was assessed by macroscopic clinical scores, histologic damage scores, myeloperoxidase and eosinophil peroxidase activity, and cytokine synthesis.

RESULTS

As gauged by all markers of gut function, infection with H diminuta caused a significant exacerbation of oxazolone-induced colitis. Indeed, while mice receiving oxazolone only began to recover approximately 3-4 days posttreatment, the cotreated group continued to deteriorate. Helminth infection, independent of oxazolone administration, enhanced IL-4, IL-5, IL-10, and IL-13 production from in vitro stimulated immune cells and evoked increases in colonic eosinophil peroxidase of cotreated mice. Finally, while knockout of natural killer (NK) and NK-T cells by administration of a neutralizing NK1.1 antibody reduced the inflammation in oxazolone and oxazolone + H diminuta-treated animals, mice in the latter group still displayed significant colitis.

CONCLUSIONS

We have shown that H diminuta infection is beneficial in other models of colitis. The current data is presented as a caveat to the position that parasitic helminths in general can be considered as a therapy for heterogeneous inflammatory disorders without careful analysis of the immunologic basis of the condition.

Dysbiosis in pouchitis: evidence of unique microfloral patterns in pouch inflammation

BACKGROUND & AIMS

Pouch inflammation after surgery for ulcerative colitis can significantly alter quality of life and thus ideally should be prevented. Dysbiosis or altered microflora is suspected to be the key pathogenic factor for pouchitis. However, dysbiosis in pouchitis has not been characterized carefully because of a lack of available sensitive microbiological technology suitable for in vivo studies in human beings. Thus, the aims of our study were as follows: (1) to show the use of the length heterogeneity polymerase chain reaction (LH-PCR) technique for studying microflora in human beings, and (2) to use the technique to characterize the microfloral patterns in the ileal pouch of patients with pouchitis.

METHODS

Microfloral patterns initially were assessed using a 16S ribosomal RNA technique (LH-PCR) to determine the qualitative changes in the luminal and mucosal intestinal flora. We subsequently cloned and sequenced the LH-PCR amplification products from the community 16S ribosomal RNA found in patients with pouchitis and in control pouch to identify the microbial species involved in pouchitis.

RESULTS

We have shown unique microfloral patterns in pouchitis. Through cloning and sequencing of the LH-PCR amplicons, we have shown the persistence of Fusobacter and Enteric species associated with the disease state and the absence of specific bacteria such as Streptococcus species in the inflamed pouch.

CONCLUSIONS

We have shown that the LH-PCR technique is suitable for studying microflora in human beings. By using this technique and the clone sequences, we have shown dysbiosis in the microbial biofilm adherent to the mucosa in pouchitis. Our data provide direct evidence of the role of bacteria in the pathogenesis of pouchitis.

Correlation between in vitro and in vivo immunomodulatory properties of lactic acid bacteria

AIM: To investigate the correlation between the in vitro immune profile of probiotic strains and their ability to prevent experimental colitis in mice.

METHODS: in vitro immunomodulation was assessed by measuring interleukin (IL)-12p70, IL-10, tumor necrosis factor alpha (TNFα) and interferon γ (IFNγ) release by human peripheral blood mononuclear cells (PBMCs) after 24 h stimulation with 13 live bacterial strains. A murine model of acute TNBS-colitis was next used to evaluate the prophylactic protective capacity of the same set of strains.

RESULTS: A strain-specific in vivo protection was observed. The strains displaying an in vitro capacity to induce higher levels of the anti-inflammatory cytokine IL-10 and lower levels of the inflammatory cytokine IL-12, offered the best protection in the in vivo colitis model. In contrast, strains leading to a low IL-10/IL-12 cytokine ratio could not significantly attenuate colitis symptoms.

CONCLUSION: These results show that we could predict the in vivo protective capacity of the studied lactic acid bacteria (LAB) based on the cytokine profile we established in vitro. The PBMC-based assay we used may thus serve as a useful primary indicator to narrow down the number of candidate strains to be tested in murine models for their anti-inflammatory potential.

Anti-inflammatory potential of the probiotic dietary supplement Lactibiane Tolérance: In vitro and in vivo considerations

BACKGROUND & AIMS

Probiotics are live microorganisms which when administered in adequate amounts confer a health benefit on the host. In inflammatory bowel disease (IBD), where major modifications of the intestinal microflora have been reported, there is an increasing interest in modulating the flora with probiotic products. This work addresses the anti-inflammatory potential of Lactibiane Tolérance, a probiotic dietary supplement (mixture of four strains) using in vitro and in vivo approaches.

METHODS

Comparison of the four individual strains and the commercial product reconstituted from them was conducted by in vitro tests (cytokine release after 24h stimulation of human peripheral blood mononuclear cells (PBMC)). The potential immunomodulatory characteristics of Lactibiane Tolérance were determined in vivo in an acute mice model of 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis. Assessment of colitis included blinded histological and macroscopic scores.

RESULTS

We showed that Lactibiane Tolérance has anti-inflammatory properties in vitro by stimulating IL-10 production and in vivo by conferring a significant protective effect in the TNBS-induced colitis model (more than 50% decrease of colitis symptoms, P<0.01).

CONCLUSIONS

These results demonstrate that a probiotic dietary supplement, Lactibiane Tolérance, can significantly prevent the initial injury of TNBS and could stimulate the initiation of clinical trials in IBD.

Homeostatic effects of TLR9 signaling in experimental colitis

The commensal microflora of the intestinal tract confer multiple health benefits to the host, including amelioration of inflammatory bowel disease (IBD). Yet, the exact mechanisms by which it ameliorates experimental colitis in animals and human IBD are largely unknown. We tested whether the attenuation of experimental colitis by probiotic bacteria is mediated by toll-like receptor (TLR) signaling. The severity of colitis was attenuated by delivery of nonviable, gamma-irradiated, or by viable probiotics, but not by heat-killed probiotics, in wild-type mice in mice deficient in TLR2 or TLR4. In contrast we did not observe any inhibition of experimental colitis by probiotics, in mice deficient in MyD88 or TLR9. Furthermore, administration of probiotic DNA ameliorated the severity of experimental colitis, whereas methylated probiotic DNA, calf thymus DNA, and Dnase-treated probiotics had no effect. In subsequent studies, we identified that TLR9-induced type 1 IFN mediates the anti-inflammatory effects in experimental colitis. The addition of neutralization antibodies to type 1 IFN abolished the anti-inflammatory effects, whereas the administration of recombinant IFN-beta mimicked the anti-inflammatory effects induced by TLR9 agonists. Taken together, these results indicate that the protective effects of probiotics are mainly mediated by their own DNA rather than by their metabolites or their ability to colonize the colon. These findings underscore the diverse effects of indigenous microbial TLR ligands in intestinal homeostasis and intestinal inflammation and suggest that strategies, that modulate type 1 IFN may be of therapeutic value for intestinal inflammatory conditions.

Selecting lactic acid bacteria for their safety and functionality by use of a mouse colitis model

Studies showed that specific probiotics might provide therapeutic benefits in inflammatory bowel disease. However, a rigorous screening of new probiotics is needed to study possible adverse interactions with the host, particularly when intended for administration to individuals with certain health risks. In this context, the objective of this study was to investigate the role of three lactobacilli (LAB) on intestinal inflammation and bacterial translocation using variations of the mouse model of 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced acute colitis. We first compared the in vitro ability of LAB to survive gastrointestinal tract (GIT) conditions and their ability to persist in the GIT of mice following daily oral administration. As a control, we included a nonprobiotic Lactobacillus paracasei strain, previously isolated from an endocarditis patient. Feeding high doses of LAB strains to healthy and to TNBS-treated mice did not induce any detrimental effect or abnormal translocation of the bacteria. Oral administration of Lactobacillus salivarius Ls-33 had a significant preventive effect on colitis in mice, while Lactobacillus plantarum Lp-115 and Lactobacillus acidophilus NCFM did not. None of the three selected LAB strains translocated to extraintestinal organs of TNBS-treated mice. In contrast, L. paracasei exacerbated colitis under severe inflammatory conditions and translocated to extraintestinal organs. This study showed that evaluations of the safety and functionality of new probiotics are recommended. We conclude that not all lactobacilli have similar effects on intestinal inflammation and that selected probiotics such as L. salivarius Ls-33 may be considered in the prevention or treatment of intestinal inflammation.

VSL#3 probiotic mixture: a review of its use in chronic inflammatory bowel diseases

VSL#3 (VSL#3) is a high-concentration probiotic preparation of eight live freeze-dried bacterial species that are normal components of the human gastrointestinal microflora, including four strains of lactobacilli (Lactobacillus casei, L. plantarum, L. acidophilus and L. delbrueckii subsp. bulgaricus), three strains of bifidobacteria (Bifidobacterium longum, B. breve and B. infantis) and Streptococcus salivarius subsp. thermophilus. Data from noncomparative trials suggest that VSL#3 has clinical potential in the treatment of active mild to moderate ulcerative colitis and as maintenance therapy for patients with ulcerative colitis in remission. In addition, a randomised, open-label, multicentre trial showed that VSL#3 in combination with low-dose balsalazide (a prodrug of mesalazine [mesalamine; 5-aminosalicylic acid]) was more effective than standard doses of basalazide or mesalazine monotherapy in the treatment of acute mild to moderate ulcerative colitis. Randomised, double-blind, placebo-controlled studies have shown VSL#3 is effective in preventing the onset of acute pouchitis in patients with newly formed surgical pouches, and in maintaining remission following antibacterial treatment of acute pouchitis in patients with a history of refractory or recurrent pouchitis. Treatment guidelines from the US and the UK include VSL#3 as a therapeutic option for the prevention of pouchitis relapse in patients with chronic pouchitis. In general, VSL#3 was well tolerated in clinical trials. Large, well designed, controlled confirmatory clinical trials will further determine the place of VSL#3 in the treatment of ulcerative colitis.

Review article: prebiotics in the gastrointestinal tract

BACKGROUND

Prebiotics are short-chain carbohydrates that alter the composition, or metabolism, of the gut microbiota in a beneficial manner. It is therefore expected that prebiotics will improve health in a way similar to probiotics, whilst at the same time being cheaper, and carrying less risk and being easier to incorporate into the diet than probiotics.

AIM

To review published evidence for prebiotic effects on gut function and human health.

METHODS

We searched the Science Citation Index with the terms prebiotic, microbiota, gut bacteria, large intestine, mucosa, bowel habit, constipation, diarrhoea, inflammatory bowel disease, Crohn's disease, ulcerative colitis, pouchitis, calcium and cancer, focussing principally on studies in humans and reports in the English language. Search of the Cochrane Library did not identify any clinical study or meta-analysis on this topic.

RESULTS

Three prebiotics, oligofructose, galacto-oligosaccharides and lactulose, clearly alter the balance of the large bowel microbiota by increasing bifidobacteria and Lactobacillus numbers. These carbohydrates are fermented and give rise to short-chain fatty acid and intestinal gas; however, effects on bowel habit are relatively small. Randomized-controlled trials of their effect in a clinical context are few, although animal studies show anti-inflammatory effects in inflammatory bowel disease, while calcium absorption is increased.

CONCLUSIONS

It is still early days for prebiotics, but they offer the potential to modify the gut microbial balance in such a way as to bring direct health benefits cheaply and safely.

Evaluation of immunomodulation by Lactobacillus casei Shirota: immune function, autoimmunity and gene expression

Lactic acid bacteria are claimed to have immunomodulating effects. Stimulation as well as suppression of T helper (Th)1 mediated immune responses, have been described for various strains. Experiments involving Lactobacillus casei Shirota (LcS) detected mainly enhancement of innate immune responses and promotion of Th1 mediated immune reactivity. To confirm and further investigate modulation of Th1 responses and development of autoimmune disease by LcS, the consequences of oral administration of LcS were assessed in several experiments. The effect of LcS varied between the different models. No modulation was found in the mitogen-induced cell proliferation and cytokine release assays in mesenteric lymph nodes of Wistar rats. LcS inhibited the Th1 mediated immune response in an adapted murine Local Lymph Node Assay (LLNA) in BALB/c mice, whereas experimental autoimmune encephalomyelitis (EAE) in Lewis rats was aggravated. These varying effects on Th1 responses indicate that beneficial as well as harmful effects on immune related disorders could occur after LcS consumption. Since microarray analysis is suggested to be more sensitive and predictive than functional tests, gene expression profiling was included as an alternative endpoint in the testing of immunomodulation. The detected gene expression profiles did not reflect the effects of LcS on the immune system. Microarray analysis may therefore have no more predictive value than immune function assays when investigating immunomodulation by probiotics. To gain further insight into effects of probiotics on immune function, experiments including cytokine assays and gene expression analysis combined with disease models could be useful.

Probiotics and their potential health claims

Many studies have attempted to identify specific positive health effects of probiotics. One of the challenges in generalizing health effects of probiotics is that different strains exert disparate effects on human health. As a result, the efficacy of one strain or species cannot necessarily be inferred from another. The objective of this review is to examine the current scientific literature that could be used as the basis for potential health claims. More specifically, this paper will review existing evidence of different probiotic strains to prevent and treat diarrhea, treat irritable bowel syndrome (IBS), treat inflammatory bowel disease, and prevent colon cancer. The strongest evidence is related to the use of Lactobacillus rhamnosus GG in the prevention and treatment of rotavirus-associated diarrhea. Further examination of the literature also shows promise in the treatment of some forms of IBS with probiotics. Future studies that use consistent supplementation regimes will allow more definitive conclusions to be drawn on the effects of probiotics on IBS, inflammatory bowel disease, and colon cancer.

Recommendations for improved use of the murine TNBS-induced colitis model in evaluating anti-inflammatory properties of lactic acid bacteria: technical and microbiological aspects

Probiotic bacteria have been shown to exert promising beneficial effects in different types of intestinal disorders, including chronic inflammation. In this context, animal models of inflammatory bowel disease are useful in studying the possible prophylactic role of candidate probiotic strains. This study aimed at evaluating the critical technological and microbiological parameters as well as the robustness of the murine trinitrobenzene sulfonic acid (TNBS)-induced model of colitis, after intragastric administration of lactic acid bacteria (LAB) preparations. A standardized methodology was applied to assess the protective effect achieved by various bacterial concentrations and culture conditions of the reference strain Lactobacillus plantarum NCIMB 8826. Not only was protection found to vary in function in different levels of colitis, but also repeated experiments showed a clear bacterial dose-dependent attenuation of colitis. The physiological stage of bacteria was shown to impact as well, with substantial, mild, or reduced improvement of inflammatory scores for exponentially growing, stationary-phase, or killed bacteria, respectively. A recombinant strain, secreting murine interleukin-10 (IL-10) and previously reported to successfully treat colitis in two different models of murine colitis (dextran sulfate sodium [DSS] and IL-10-deficient mice), was used to validate the final experimental conditions. In conclusion, we identified and optimized some of the key parameters that need to be controlled in order to ensure reliable comparison of results generated over a long period of time or independent experiments. The recommendations for an improved model presented here will prove to be helpful for reproducible, independent comparison of the anti-inflammatory potential of wild-type or recombinant candidate probiotic strains, whether administered as pure cultures or as blends.

Probiotics: a practical review of their role in specific clinical scenarios

The use of probiotics (live viable microbial organisms) in the treatment of specific diseases has evolved into an extremely valuable option yet to be optimally used in clinical medicine. Probiotics have been shown to have immunomodulating properties and enhance the mucosal barrier. This review will briefly discuss the use of probiotics in inflammatory bowel disease, pancreatitis, liver transplantation, and various uses in diarrhea. When using probiotics, one must be cautious of the sometime overzealous claims that are commonly made when dealing with medical foods. As we begin to appreciate the degree of complexity that our indigenous microbial population has on health, it is only then that we can begin to understand the importance in disease. In the arena of probiotics, numerous fundamental questions remain unanswered.

Pathophysiological role of Toll-like receptor 5 engagement by bacterial flagellin in colonic inflammation

Commensal and enteroinvasive microbes in the human gut release bacterial flagellin, a specific microbial ligand of Toll-like receptor 5 (TLR5). However, the pathophysiological role of bacterial flagellin in gastrointestinal inflammation has not been determined. Here we evaluated the role of bacterial flagellin using native human colonic mucosa and the mouse colitis model of dextran sulfate sodium (DSS). We demonstrate that, in intact human colonic mucosa, the flagellin/TLR5 response occurs only after exposure to the basolateral, not the apical, surface, implying a basolaterally polarized TLR5 response in human colonic mucosa. In this context, flagellin exposure to injured colonic mucosa due to DSS administration in mice resulted in a TLR5-associated response evaluated by in vivo activation of mitogen-activated protein kinase/extracellular signal-related kinase 1/2 (MEK1/2) and elevated IL-6, TNF-alpha, and keratinocyte-derived chemokine production, whereas intact colonic mucosa did not respond to flagellin. Moreover, flagellin exposure to injured mouse colon in vivo, but not to intact colon, also significantly aggravated colonic inflammation, increased mouse mortality, and enhanced histopathological damage in the colonic mucosa. However, the TLR2-specific agonist, peptidoglycan or lipoteichoic acid, did not cause an inflammatory response in intact or DSS-injured mouse colon. Furthermore, intracolonic flagellin administration in mice causes severe apoptosis in colonic epithelium disrupted by DSS administration. These data suggest that intracolonic flagellin via TLR5 engagement is able to elicit inflammatory responses in disrupted colon, whereas the normal colon is not responsive to bacterial flagellin. These results demonstrate that bacterial flagellin plays an important role in the development and progress of colitis.

Effects of dietary fiber on inflammatory bowel disease

The chronic idiopathic inflammatory bowel diseases (IBDs), namely Crohn's disease and ulcerative colitis, appear to be derived from an inappropriate reaction towards a luminal agent, most probably driven by the intestinal microflora, which upregulates the synthesis and release of different pro-inflammatory mediators, thus contributing to tissue damage that characterizes these intestinal conditions. Several studies have reported that IBD is associated with impairment in short-chain fatty acid (SCFA) production, mainly acetate, propionate, and butyrate. They are produced in the large bowel by anaerobic bacterial fermentation of undigested dietary carbohydrates and fiber polysaccharides, with butyrate being considered as the major fuel source for colonocytes. These SCFAs have been proposed to play a key role in the maintenance of colonic homeostasis. Therefore, it is reasonable to consider therapeutic approaches that increase colonic SCFA production, as it can be achieved by administration of dietary fiber to IBD patients. Unfortunately, there is quite limited documentation of efficacy of dietary fiber in properly designed trials. This review discusses the rationale, available evidence for the use of dietary fiber and its mechanisms of action in the treatment and prevention of IBDs.

Probiotic therapy in the prevention of pouchitis onset: decreased interleukin-1beta, interleukin-8, and interferon-gamma gene expression

BACKGROUND

Probiotic therapy has been shown to prevent the onset of pouchitis and to improve the quality of life in ulcerative colitis patients who required ileal pouch anal anastomosis. Pouchitis has been associated with elevated levels of proinflammatory cytokines and chemokines.

METHODS

In this retrospective analysis of archived endoscopic samples from responding patients enrolled in the above-mentioned trial, we were interested in studying mucosal gene expression of the pleiotropic proinflammatory cytokines (interleukin-1beta, interleukin-6), TH1 cytokines (interferon-gamma, tumor necrosis factor-alpha, interleukin-12), regulatory cytokines (interleukin-10, transforming growth factor-beta), and the chemokine interleukin-8. In addition to assessment of cytokine gene expression, the presence of polymorphonuclear cells in the mucosal tissue was evaluated.

RESULTS

Data show that patients who were treated with probiotics had significant lower mucosal mRNA expression levels of interleukin-1beta, interleukin-8, and interferon-gamma compared with placebo-treated patients. In addition, a lower number of polymorphonuclear cells was present in the tissue of patients within the probiotic group compared with the number of polymorphonuclear cells in the tissue of patients receiving placebo and patients having an episode of pouchitis.

CONCLUSIONS

These data suggest that probiotic treatment regulates the mucosal immune response by reducing mucosal levels of neutrophil-chemoattractant IL-8 and tissue influx of polymorphonuclear cells, and may further act by inhibition of T-cell activation, by reinforcement of barrier function and by a tight control of the potent pro-inflammatory cytokine IL-1beta.

Drug treatment of ulcerative colitis: unfractionated heparin, low molecular weight heparins and beyond

Ulcerative colitis (UC) is characterised by chronic inflammation of the colon of unknown aetiology. Medical treatment of UC is complex and sometimes unsatisfactory. A total of 75% of patients experience relapses during the course of their illness and 20 - 25% require a colostomy. Recent years have witnessed a paradigm shift in the way UC is medically treated. The focus has now shifted to newer forms of therapy along with the older established drugs such as sulfasalazine and corticosteroids. Unfractionated heparin and low molecular weight heparins have been tested for their efficacy in patients with UC with conflicting results in various studies. Immunosuppressive and immune-based therapies, drugs modifying biological responses, prebiotics, probiotics, symbiotics, melatonin and topical butyrate have all been tested with variable success. The current review delineates the recent therapeutic alternatives in UC with main emphasis on heparins.

Bacillus clausii probiotic strains: antimicrobial and immunomodulatory activities

The clinical benefits observed with probiotic use are mainly attributed to the antimicrobial substances produced by probiotic strains and to their immunomodulatory effects. Currently, the best-documented probiotic bacteria used in human therapy are lactic acid bacteria. In contrast, studies aiming to characterize the mechanisms responsible for the probiotic beneficial effects of Bacillus are rare. The current work seeks to contribute to such characterization by evaluating the antimicrobial and immunomodulatory activities of probiotic B. clausii strains. B. clausii strains release antimicrobial substances in the medium. Moreover, the release of these antimicrobial substances was observed during stationary growth phase and coincided with sporulation. These substances were active against Gram-positive bacteria, in particular against Staphylococcus aureus, Enterococcus faecium, and Clostridium difficile. The antimicrobial activity was resistant to subtilisin, proteinase K, and chymotrypsin treatment, whereas it was sensitive to pronase treatment. The evaluation of the immunomodulatory properties of probiotic B. clausii strains was performed in vitro on Swiss and C57 Bl/6j murine cells. The authors demonstrate that these strains, in their vegetative forms, are able to induce NOS II synthetase activity, IFN-gamma production, and CD4 T-cell proliferation.

Unravelling the complex genetics of inflammatory bowel disease

The rapid pace of progress in molecular genetics over the past 15 years--since the seminal description of the polymerase chain reaction--has led to the identification of the genes involved in many single gene disorders. These successes in the laboratory have already led directly to clinical applications in diagnosis, pharmacogenetics, and the development of new therapies. Progress in unravelling the genetics of complex diseases has been less straightforward. However, real excitement has followed the identification of the NOD 2/CARD 15 gene as an important determinant of susceptibility to Crohn's disease.(1,)(2) Not only has this finding provided a proof of principle for the technique of genome-wide scanning in complex disorders, but the discovery also has given real insight into the primary pathophysiology involved in chronic inflammatory bowel disease. The background to this discovery and its implications form the basis for the present article.