151
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Nadal I, Donant E, Ribes-Koninckx C, Calabuig M, Sanz Y. Imbalance in the composition of the duodenal microbiota of children with coeliac disease. J Med Microbiol 2008; 56:1669-1674. [PMID: 18033837 DOI: 10.1099/jmm.0.47410-0] [Citation(s) in RCA: 272] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Coeliac disease (CD) is the most common immune-mediated enteropathy characterized by chronic inflammation of the small intestinal mucosa. The ingestion of gluten is responsible for the symptoms of CD, but other environmental factors are also thought to play a role in this disorder. In this study, the composition of the duodenal microbiota of coeliac children with active disease, symptom-free CD patients on a gluten-free diet and control children was determined. Bacteriological analyses of duodenal biopsy specimens were carried out by fluorescent in situ hybridization coupled with flow cytometry. The proportions of total bacteria and Gram-negative bacteria were significantly higher in CD patients with active disease than in symptom-free CD patients and controls. Bacteroides and Escherichia coli groups were significantly more abundant in CD patients with active disease than in controls, whilst these bacterial deviations were normalized in symptom-free CD patients. The ratio of Lactobacillus--Bifidobacterium to Bacteroides--E. coli was significantly reduced in coeliac patients with either active or inactive disease compared with controls. The differences in Atopobium, Eubacterium rectale--Clostridium coccoides, Clostridium histolyticum, Clostridium lituseburense, sulphate-reducing bacteria and Faecalibacterium prausnitzii populations among the three groups of children were less relevant. Overall, the higher incidence of Gram-negative and potentially pro-inflammatory bacteria in the duodenal microbiota of coeliac children was linked to the symptomatic presentation of the disease and could favour the pathological process of the disorder.
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Affiliation(s)
- Inmaculada Nadal
- Instituto de Agroquímica y Tecnología de Alimentos (Consejo Superior de Investigaciones Cientificas), Apartado 73, 46100 Burjassot, Valencia, Spain
| | - Esther Donant
- Hospital Universitario La Fe, Avenida Campanar 21, 40009 Valencia, Spain
| | | | - Miguel Calabuig
- Hospital General Universitario, Avenida Tres Cruces s/n, 46014 Valencia, Spain
| | - Yolanda Sanz
- Instituto de Agroquímica y Tecnología de Alimentos (Consejo Superior de Investigaciones Cientificas), Apartado 73, 46100 Burjassot, Valencia, Spain
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152
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Mitsuyama K, Sata M. Gut microflora: a new target for therapeutic approaches in inflammatory bowel disease. Expert Opin Ther Targets 2008; 12:301-12. [DOI: 10.1517/14728222.12.3.301] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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153
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Sartor RB. Microbial influences in inflammatory bowel diseases. Gastroenterology 2008; 134:577-94. [PMID: 18242222 DOI: 10.1053/j.gastro.2007.11.059] [Citation(s) in RCA: 1331] [Impact Index Per Article: 83.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2007] [Accepted: 11/28/2007] [Indexed: 02/07/2023]
Abstract
The predominantly anaerobic microbiota of the distal ileum and colon contain an extraordinarily complex variety of metabolically active bacteria and fungi that intimately interact with the host's epithelial cells and mucosal immune system. Crohn's disease, ulcerative colitis, and pouchitis are the result of continuous microbial antigenic stimulation of pathogenic immune responses as a consequence of host genetic defects in mucosal barrier function, innate bacterial killing, or immunoregulation. Altered microbial composition and function in inflammatory bowel diseases result in increased immune stimulation, epithelial dysfunction, or enhanced mucosal permeability. Although traditional pathogens probably are not responsible for these disorders, increased virulence of commensal bacterial species, particularly Escherichia coli, enhance their mucosal attachment, invasion, and intracellular persistence, thereby stimulating pathogenic immune responses. Host genetic polymorphisms most likely interact with functional bacterial changes to stimulate aggressive immune responses that lead to chronic tissue injury. Identification of these host and microbial alterations in individual patients should lead to selective targeted interventions that correct underlying abnormalities and induce sustained and predictable therapeutic responses.
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Affiliation(s)
- R Balfour Sartor
- Department of Medicine, Center for Gastrointestinal Biology and Disease, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
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154
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Abstract
PURPOSE OF REVIEW To highlight the evidence supporting the role of altered commensal gut flora in human disease. While the contribution of the indigenous gut microbial community is widely recognized, only recently has there been evidence pointing to indigenous flora in disease. RECENT FINDINGS This review discusses recent evidence pointing to the role of altered commensal gut flora in such common conditions as irritable bowel syndrome and inflammatory bowel disease. Recent studies document the intricate relationship between the vast population of microbes that live in our gut and the human host. Since increased intestinal permeability and immune activation are consequences of an altered host-gut microbial relationship, what are the clinical effects of this shift in relationship? SUMMARY We focus on the example of an abnormal expansion of gut microbial flora into the small bowel or small intestinal bacterial overgrowth and discuss the effects of bacterial overgrowth on the human host in acute pancreatitis, bacterial gastroenteritis, irritable bowel syndrome, inflammatory bowel disease, hepatic encephalopathy, and fibromyalgia and burn injury. The identification of the underlying role of altered commensal gut microbiota in these and other human diseases could lead to novel diagnostic and therapeutic strategies that would improve clinical outcome.
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155
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Abstract
PURPOSE OF REVIEW Sanitation, antibiotics and vaccines have done more to extend life expectancy than any other medical innovation. Concern exists, however, about the link between hygiene and increased incidence of immune-mediated disorders. RECENT FINDINGS Studies confirm higher prevalence of asthma and allergic diseases in urban areas and developed countries rather than rural areas and developing countries. There is an inverse association between family size and disease. The debate over whether infection precipitates or prevents immune dysregulation remains a contentious one. Our knowledge about the microbial composition of the intestinal ecosystem is expanding rapidly with the introduction of molecular techniques. Differences in gut bacteria between health and atopy or inflammatory bowel disease are repeatedly reported. Recent data in inflammatory bowel disease suggest reduced species diversity and temporal instability of the gut microecosystem. The gut is a major site for induction of regulatory T cells, which secrete immunosuppressive cytokines. Not only infections, but also some commensals induce regulatory pathways, which seem to be functionally deficient in multiple sclerosis, allergies and inflammatory bowel disease. SUMMARY Changes in lifestyle leading to decreased exposure to certain nonpathogenic species that are important for the development of immunoregulatory mechanisms are probably associated with increased incidence of some immune-mediated diseases, such as allergies and inflammatory bowel disease.
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Affiliation(s)
- Francisco Guarner
- Digestive System Research Unit, Ciberehd, University Hospital Vall d'Hebron, Barcelona, Spain.
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156
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Abstract
Over the past few years, none of the numerous conditions that are grouped under the broad designation of 'chronic inflammatory or autoimmune disorders' has undergone as much scientific and clinical progress as the two main forms of inflammatory bowel disease (IBD), Crohn's disease (CD) and ulcerative colitis (UC). Progress has occurred in all major areas relevant to IBD pathogenesis, which include the external environment, genetics, microbial factors, and the immune system. This review presents an update on the specific major advances that have occurred in each of these four areas, briefly discusses the therapeutic implications of the observed progress, and points out the additional work that needs to be accomplished in the next few years to reach a full understanding of IBD etiopathogenesis.
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Affiliation(s)
- Franco Scaldaferri
- Department of Gastroenterology and Hepatology, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA
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157
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Cabré E, A Gassull M. Probiotics for preventing relapse or recurrence in Crohn's disease involving the ileum: Are there reasons for failure? J Crohns Colitis 2007; 1:47-52. [PMID: 21172184 DOI: 10.1016/j.crohns.2007.06.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2007] [Accepted: 06/29/2007] [Indexed: 02/08/2023]
Abstract
In contrast to ulcerative colitis and pouchitis, benefits of probiotic therapy in preventing recurrence/relapse in Crohn's disease (mostly involving the ileum) are far from being proven. The lack of response in this setting does not seem attributable to a lower relevance of dysbiosis in ileal Crohn's disease, since this - or at least the presence of increased mucosal amounts of potentially pathogen bacteria - has been proven to occur in the ileum of Crohn's disease patients. Available data indicate that whereas in ulcerative colitis (and to a lesser extent in colonic Crohn's disease) the innate immune response is enhanced, it is constitutively depressed in ileal Crohn's disease. Therefore, attempts to modify the composition of intestinal microflora in colonic IBD or pouchitis by means of probiotics do make sense. In contrast, supplying additional bacteria (even being probiotics) to an ileum with decreased antibacterial defence does not seem reasonable. In fact, the presence of intestinal contents has been reported to be related to postoperative recurrence in ileo-caecal Crohn's disease, and antibiotic treatment in effective to prevent its development.
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Affiliation(s)
- Eduard Cabré
- Department of Gastroenterology, Hospital Universitari Germans Trias i Pujol, Carretera del Canyet s/n 08916 Badalona, Catalonia, Spain
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158
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Latella G, Fiocchi C, Caprilli R. Late-breaking news from the "4th International Meeting on Inflammatory Bowel Diseases" Capri, 2006. Inflamm Bowel Dis 2007; 13:1031-50. [PMID: 17309072 DOI: 10.1002/ibd.20127] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
At the "4th International Meeting on Inflammatory Bowel Diseases: on the Way to New Therapies," Capri, 2006, genetics, bacteria-host interactions, immunomodulation, and tissue response were discussed deeply in order to understand, rationalize, and develop novel therapies. About genetics, the importance of a better understanding of the nature of known loci and of the putative associations was stressed. It was confirmed that genotype-phenotype associations in inflammatory bowel disease (IBD) have important clinical and therapeutic implications. The importance of the search for dominant bacterial antigens in chronic immune-mediated intestinal inflammation emerged, as well as knowledge of cellular and molecular mechanisms of bacterial-host interactions. It was discussed how innate and adaptive immunity signaling events can perpetuate chronic inflammation. Signal transduction pathways provide an intracellular mechanism by which cells respond and adapt to environmental stress. The identification of these signals have led to a greater understanding of the pathogenesis of IBD and pointed to potential therapeutic targets. It was shown that immune homeostasis is lost in IBD, resulting in a complex tissue response involving the action of immune and nonimmune cells. The nonimmune tissue response in IBD could be regarded as a new target for control of chronic intestinal inflammation. The changing role of biotherapy in IBD was widely discussed and in particular the anti-TNF-alpha monoclonal antibodies. Granulocyte-colony stimulating factor (GM-CSF) and stem cells therapies were also discussed. The risk-to-benefit ratio of the novel therapies was analyzed in detail. Finally, future directions for basic science and the unmet needs for clinical practice were presented.
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Affiliation(s)
- Giovanni Latella
- Department of Internal Medicine, GI Unit, University of L'Aquila, L'Aquila, Italy
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159
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Andoh A, Sakata S, Koizumi Y, Mitsuyama K, Fujiyama Y, Benno Y. Terminal restriction fragment length polymorphism analysis of the diversity of fecal microbiota in patients with ulcerative colitis. Inflamm Bowel Dis 2007; 13:955-62. [PMID: 17455205 DOI: 10.1002/ibd.20151] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND Terminal restriction fragment length polymorphism (T-RFLP) analysis is a powerful tool to assess the diversity of complexed microbiota. This permits rapid comparison of microbiota from many samples. In this study, we performed T-RFLP analysis of the fecal microbiota from patients with ulcerative colitis (UC). METHODS Forty-four patients with UC (23 women and 21 men, median age 25 years) and 46 healthy individuals (25 women and 21 men, median age 34 years) were enrolled in this study. DNA was extracted from their stool samples, and the 16S rRNA genes were amplified by PCR. The PCR products were then digested with HhaI and/or MspI restriction enzymes, and the length of the T-RF was determined. RESULTS The fecal microbial communities were classified in 8 clusters. Almost all the healthy individuals (39 of 46) were included in cluster I, and most of the UC patients could be divided into the other 7 clusters, indicating that fecal bacterial communities are different between healthy individuals and active UC patients. Some T-RFs, derived from the unclassified bacteria, Ruminococcus, Eubacterium, Fusobacterium, gammaproteobacteria, unclassified Bacteroides, and unclassified Lactobacillus, were detected in the UC patients, but not in the healthy individuals. The T-RFLP patterns were also different between the active patients and inactive (remission) patients. The T-RF derived from the unclassified bacteria, Ruminococcus and Eubacterium, and the T-RFs derived from the unclassified bacteria, Eubacterium, and Fusobacterium were predominantly detected in the active patients not the inactive patients. In contrast, the T-RFs derived from Lactobacillus and unclassified Lactobacillus were more predominant in the inactive (remission) patients. In 4 patients with proctitis, the pattern of fecal microbial diversity was very similar. CONCLUSIONS T-RFLP analyses showed that the diversity of fecal microbiota in patients with UC was different from that in healthy individuals. Unclassified bacteria, as well as known bacteria, can contribute to alterations in the bacterial diversity of UC patients.
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Affiliation(s)
- Akira Andoh
- Department of Internal Medicine, Shiga University of Medical Science, Otsu, Japan.
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160
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Sepehri S, Kotlowski R, Bernstein CN, Krause DO. Microbial diversity of inflamed and noninflamed gut biopsy tissues in inflammatory bowel disease. Inflamm Bowel Dis 2007; 13:675-83. [PMID: 17262808 DOI: 10.1002/ibd.20101] [Citation(s) in RCA: 175] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
BACKGROUND Inflammatory bowel disease (IBD) is a chronic gastrointestinal condition without any known cause or cure. An imbalance in normal gut biota has been identified as an important factor in the inflammatory process. METHODS Fifty-eight biopsies from Crohn's disease (CD, n = 10), ulcerative colitis (UC, n = 15), and healthy controls (n = 16) were taken from a population-based case-control study. Automated ribosomal intergenic spacer analysis (ARISA) and terminal restriction fragment length polymorphisms (T-RFLP) were used as molecular tools to investigate the intestinal microbiota in these biopsies. RESULTS ARISA and T-RFLP data did not allow a high level of clustering based on disease designation. However, if clustering was done based on the inflammation criteria, the majority of biopsies grouped either into inflamed or noninflamed groups. We conducted statistical analyses using incidence-based species richness and diversity as well as the similarity measures. These indices suggested that the noninflamed tissues form an intermediate population between controls and inflamed tissue for both CD and UC. Of particular interest was that species richness increased from control to noninflamed tissue, and then declined in fully inflamed tissue. CONCLUSIONS We hypothesize that there is a recruitment phase in which potentially pathogenic bacteria colonize tissue, and once the inflammation sets in, a decline in diversity occurs that may be a byproduct of the inflammatory process. Furthermore, we suspect that a better knowledge of the microbial species in the noninflamed tissue, thus before inflammation sets in, holds the clues to the microbial pathogenesis of IBD.
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Affiliation(s)
- Shadi Sepehri
- Department of Medical Microbiology and Infectious Diseases, Winnipeg, Manitoba, Canada
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161
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Tannock GW. What immunologists should know about bacterial communities of the human bowel. Semin Immunol 2007; 19:94-105. [PMID: 17035042 DOI: 10.1016/j.smim.2006.09.001] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2006] [Accepted: 09/05/2006] [Indexed: 12/20/2022]
Abstract
The human bowel is home to a bacterial community of much complexity. This article summarizes current bacteriological knowledge of the community and highlights topics of potential interest to innovative immunologists. The role of the bacterial community in the development and regulation of the immune system of neonates seems likely to be a particularly important area of future research.
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Affiliation(s)
- Gerald W Tannock
- Department of Microbiology and Immunology, University of Otago, P.O. Box 56, 720 Cumberland Street, Dunedin, New Zealand.
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162
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Abstract
Two broad hypotheses have arisen regarding the fundamental nature of the pathogenesis of inflammatory bowel diseases (IBDs, which include ulcerative colitis and Crohn disease). The first contends that primary dysregulation of the mucosal immune system leads to excessive immunologic responses to normal microflora. The second suggests that changes in the composition of gut microflora and/or deranged epithelial barrier function elicits pathologic responses from the normal mucosal immune system. Here we examine these hypotheses and conclude that IBD is indeed characterized by an abnormal mucosal immune response but that microbial factors and epithelial cell abnormalities can facilitate this response.
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Affiliation(s)
- Warren Strober
- Mucosal Immunity Section, Laboratory of Host Defenses, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD 20892, USA.
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